Features
Linear Motion in Washdown: Select the right components for food-processing equipment Featured
Written by PEM Staff Monday, 08 April 2013
A washdown environment is one that utilizes, either by hand or by automatic means, cleaning with water, chemicals or a mixture of these. This washdown process can be as simple as a cloth and bucket or use of a hose to spray clean — or it can be under sophisticated high-pressure, controlled systems. The goal of these washdown operations is to eliminate bacteria and other microorganisms that can cause and spread disease. In recent years, examples of incidents such as e-coli breakouts and mad cow disease have rightfully led to greater scrutiny on processing equipment that may contain areas where unwanted bacteria can develop.
MATERIALS
One key to successful linear motion design for a washdown environment is the choice of the materials used for the bearing, shaft or rail, and seal components. To achieve the requirements needed for corrosion resistance, proper standard and regulation compliance, and machine performance requires the right selection of materials.
Stainless steel is typically the preferred material for general use in direct food contact areas because of its corrosion resistance and durability. However, there are variations in stainless steel grades mostly in the levels of chromium and nickel.
• 300 Series: the most widely accepted material for food grade and medical applications. It is relatively soft, cannot be hardened and is also non-magnetic. Each of the grades (303, 304 and 316) can have different types that have slightly different formulations with varying strengths and weakness based on the addition to the mixtures.
• 400 Series: the most widely available and most used in industry is the 440, which can be heat treated and hardened. It is often used for cutlery, linear shafting and in applications requiring good wear resistance. It can be hardened up to approximately RC58; however, due to added carbon in its makeup, 440 will oxidize under washdown conditions.
Stainless steels do not rust with a red colored oxide on the surface the way that “rust” is normally observed. If these types of particles appear on a stainless surface, it is most likely due to iron particulate that has contaminated that surface or is coming from fillers within the bearing. To cleanse that surface, a solution of 10-per-cent nitric acid and two-per-cent hydrofluoric acid at room temperature can be effective.
Aluminum can be used in some areas of a washdown environment where weight is a concern. However, be aware that bare aluminum will have poor corrosion resistance and is susceptible to pitting and cracking. In washdown conditions, aluminum MUST be coated for protection. Often anodizing, ceramic coating, or other types of coatings with PTFE or other fillers are used, but may not provide the resistance or life that stainless steel offers. In more caustic chemical washdown environments, stainless steel is the preferred material.
Electroless nickel coatings have become increasingly popular because of their corrosion and wear resistance combined with a smooth polished appearance. Some forms include a PTFE infusion to aid in non- sticking properties. Most forms of this coating are FDA compliant as well.
Non-metal materials like plastics, polymers and fillers tend not to have the corrosion resistance and durability of metal surfaces over time and are thus not used as often as major components in food and pharmaceutical equipment. However, due to cost, weight, manufacturability, etc., they are increasingly being used “under the hood”, inside of mechanical drive components, guides, bearings, fasteners and more. Many solid plastics, such as injection molded bearing inserts, can present drawbacks in washdown applications in that most will absorb liquid, causing the component to swell and increasing the potential for binding and failure.
Also, be aware that each of the standards organizations covered earlier has extensive information on a variety of plastic materials that are acceptable.
COMPONENTS
Linear motion components offer their own unique challenges when being designed for washdown applications. Rotating components need to be mounted and sealed within a limited area, but because the moving component of a bearing, slide or actuator system travels in a linear fashion, the space needing to be sealed or cleaned will be far greater; often up to several feet. Below are some tips on how to minimize areas of potential bacteria buildup and maximize cleanability.
Bearings
There are two basic types to be aware of when considering plain bearings. When using plastic inserts, be aware of moisture absorption that will lead to the bearing material swelling. This can result in binding issues. If the inside diameter is increased to deal with the swelling, it can often cause loose tolerances and inaccuracies in the system.
It is best to avoid open-ended bearings with grooves or inserts in areas that may be susceptible to bacteria buildup. These two-piece type bearings will allow the microscopic bacteria to seat in the crevices, grooves, and to hide between the outer shell of the bearing and the plastic bearing insert. One- piece bonded bearings eliminate this potential for bacteria collection.
The same principle is true for recirculating ball bearing type products, such as roundway linear ball bearings and profile rails. They provide advantages, such as low friction and tight tolerances, and are often available in stainless steel materials with FDA compliant lubrication. However, they can present disadvantages in that they require grease lubrication to be used due to the metal-to-metal contact. This lubrication picks up material from the food items being processed and can then become trapped inside of the multiple crevices and cavities around the balls and in the raceways of the bearing. This can potentially be a breeding ground for unwanted bacteria.
The best solution for most applications is to utilize a one-piece bonded bearing. The bearing materials, are PTFE based, self-lubricating and require no external lubrication that can collect potentially contaminated material. In addition, there are no grooves, crevices, or space between liner and bearing shell where residue can become lodged allowing bacteria to grow. The bearing material and outer shell are bonded together creating a true one-piece bearing.
In vertical applications such as those found on in-line and carousel bottle filling machines, it is advisable to utilize a bearing that is sealed at the top end. This eliminates contamination and the majority of fluid in the filling and washdown process from penetrating the bearing ID. Yet it allows the liquids that do get into the bearing system to easily flow through and exit at the bottom of the assembly.
Another area of potential concern in this type of configuration is that the many multiple component sub-assemblies utilizing a parallel shaft design can experience bearing binding problems due to misalignment. In addition, these multiple components are also susceptible to bacteria buildup around the connectors and joints. Newer technology that incorporates dual rail load capacities and functionality into a single rail design can eliminate potential areas of contamination collection.
Rail Design/Selection
It is best to avoid as much component assembly as possible in a washdown environment. Traditional methods for linear assemblies utilize a shaft and support rail bolted together, which are then bolted to a mounting plate or carriage. Each of these connection points creates a joint, crack, or crevice and a potential location where liquids can penetrate or where bacteria can begin to cling and buildup over time.
New technology in linear motion has created slide assemblies that eliminate the need for traditional multiple components and connectors. Unique two-piece slide systems are an ideal solution for washdown environments. In addition, these new style linear motion components are designed with smoothly curved edges that do not have recesses where buildup can occur.
Fasteners
When possible, avoid mounting connectors from the washdown side. They protrude and create another area where contamination can collect. It is best to bring the connector up through the bottom of the rail to be mounted. If necessary and connectors enter the washdown area, use a domed nut for easier cleaning.
COMPONENT LOCATION
Particularly in food grade applications, it is important to consider the location where the linear motion device is to be mounted in relation to the food being processed. When components that are not compliant or that do not meet other regulations for food contact, are used over the open food path or in a position where it could potentially come into contact with the food items being processed, risk can be eliminated by installing a stainless steel shield or cover over the components.
When constructing shields and other covers, it is important to give consideration as to how the panels and plates are to be connected or welded together. Small collection points for moisture and the potential for corrosion and bacteria buildup are the result of leaving the irregular surface of a weld exposed to the splash area. Whenever possible, the best-case scenario is to radius all corners.
Another tactic used to help in the management of moisture and fluids around linear motion components is to add weep holes, drainage channels, slots, or other porting features designed to channel the moisture away from potential pooling areas.
This is an edited article based on the PBC Linear whitepaper, “Linear Motion Design for Washdown Applications.” For more information, visit www.pbclinear.com.
MATERIALS
One key to successful linear motion design for a washdown environment is the choice of the materials used for the bearing, shaft or rail, and seal components. To achieve the requirements needed for corrosion resistance, proper standard and regulation compliance, and machine performance requires the right selection of materials.
Stainless steel is typically the preferred material for general use in direct food contact areas because of its corrosion resistance and durability. However, there are variations in stainless steel grades mostly in the levels of chromium and nickel.
• 300 Series: the most widely accepted material for food grade and medical applications. It is relatively soft, cannot be hardened and is also non-magnetic. Each of the grades (303, 304 and 316) can have different types that have slightly different formulations with varying strengths and weakness based on the addition to the mixtures.
• 400 Series: the most widely available and most used in industry is the 440, which can be heat treated and hardened. It is often used for cutlery, linear shafting and in applications requiring good wear resistance. It can be hardened up to approximately RC58; however, due to added carbon in its makeup, 440 will oxidize under washdown conditions.
Stainless steels do not rust with a red colored oxide on the surface the way that “rust” is normally observed. If these types of particles appear on a stainless surface, it is most likely due to iron particulate that has contaminated that surface or is coming from fillers within the bearing. To cleanse that surface, a solution of 10-per-cent nitric acid and two-per-cent hydrofluoric acid at room temperature can be effective.
Aluminum can be used in some areas of a washdown environment where weight is a concern. However, be aware that bare aluminum will have poor corrosion resistance and is susceptible to pitting and cracking. In washdown conditions, aluminum MUST be coated for protection. Often anodizing, ceramic coating, or other types of coatings with PTFE or other fillers are used, but may not provide the resistance or life that stainless steel offers. In more caustic chemical washdown environments, stainless steel is the preferred material.
Electroless nickel coatings have become increasingly popular because of their corrosion and wear resistance combined with a smooth polished appearance. Some forms include a PTFE infusion to aid in non- sticking properties. Most forms of this coating are FDA compliant as well.
Non-metal materials like plastics, polymers and fillers tend not to have the corrosion resistance and durability of metal surfaces over time and are thus not used as often as major components in food and pharmaceutical equipment. However, due to cost, weight, manufacturability, etc., they are increasingly being used “under the hood”, inside of mechanical drive components, guides, bearings, fasteners and more. Many solid plastics, such as injection molded bearing inserts, can present drawbacks in washdown applications in that most will absorb liquid, causing the component to swell and increasing the potential for binding and failure.
Also, be aware that each of the standards organizations covered earlier has extensive information on a variety of plastic materials that are acceptable.
COMPONENTS
Linear motion components offer their own unique challenges when being designed for washdown applications. Rotating components need to be mounted and sealed within a limited area, but because the moving component of a bearing, slide or actuator system travels in a linear fashion, the space needing to be sealed or cleaned will be far greater; often up to several feet. Below are some tips on how to minimize areas of potential bacteria buildup and maximize cleanability.
Bearings
There are two basic types to be aware of when considering plain bearings. When using plastic inserts, be aware of moisture absorption that will lead to the bearing material swelling. This can result in binding issues. If the inside diameter is increased to deal with the swelling, it can often cause loose tolerances and inaccuracies in the system.
It is best to avoid open-ended bearings with grooves or inserts in areas that may be susceptible to bacteria buildup. These two-piece type bearings will allow the microscopic bacteria to seat in the crevices, grooves, and to hide between the outer shell of the bearing and the plastic bearing insert. One- piece bonded bearings eliminate this potential for bacteria collection.
The same principle is true for recirculating ball bearing type products, such as roundway linear ball bearings and profile rails. They provide advantages, such as low friction and tight tolerances, and are often available in stainless steel materials with FDA compliant lubrication. However, they can present disadvantages in that they require grease lubrication to be used due to the metal-to-metal contact. This lubrication picks up material from the food items being processed and can then become trapped inside of the multiple crevices and cavities around the balls and in the raceways of the bearing. This can potentially be a breeding ground for unwanted bacteria.
The best solution for most applications is to utilize a one-piece bonded bearing. The bearing materials, are PTFE based, self-lubricating and require no external lubrication that can collect potentially contaminated material. In addition, there are no grooves, crevices, or space between liner and bearing shell where residue can become lodged allowing bacteria to grow. The bearing material and outer shell are bonded together creating a true one-piece bearing.
In vertical applications such as those found on in-line and carousel bottle filling machines, it is advisable to utilize a bearing that is sealed at the top end. This eliminates contamination and the majority of fluid in the filling and washdown process from penetrating the bearing ID. Yet it allows the liquids that do get into the bearing system to easily flow through and exit at the bottom of the assembly.
Another area of potential concern in this type of configuration is that the many multiple component sub-assemblies utilizing a parallel shaft design can experience bearing binding problems due to misalignment. In addition, these multiple components are also susceptible to bacteria buildup around the connectors and joints. Newer technology that incorporates dual rail load capacities and functionality into a single rail design can eliminate potential areas of contamination collection.
Rail Design/Selection
It is best to avoid as much component assembly as possible in a washdown environment. Traditional methods for linear assemblies utilize a shaft and support rail bolted together, which are then bolted to a mounting plate or carriage. Each of these connection points creates a joint, crack, or crevice and a potential location where liquids can penetrate or where bacteria can begin to cling and buildup over time.
New technology in linear motion has created slide assemblies that eliminate the need for traditional multiple components and connectors. Unique two-piece slide systems are an ideal solution for washdown environments. In addition, these new style linear motion components are designed with smoothly curved edges that do not have recesses where buildup can occur.
Fasteners
When possible, avoid mounting connectors from the washdown side. They protrude and create another area where contamination can collect. It is best to bring the connector up through the bottom of the rail to be mounted. If necessary and connectors enter the washdown area, use a domed nut for easier cleaning.
COMPONENT LOCATION
Particularly in food grade applications, it is important to consider the location where the linear motion device is to be mounted in relation to the food being processed. When components that are not compliant or that do not meet other regulations for food contact, are used over the open food path or in a position where it could potentially come into contact with the food items being processed, risk can be eliminated by installing a stainless steel shield or cover over the components.
When constructing shields and other covers, it is important to give consideration as to how the panels and plates are to be connected or welded together. Small collection points for moisture and the potential for corrosion and bacteria buildup are the result of leaving the irregular surface of a weld exposed to the splash area. Whenever possible, the best-case scenario is to radius all corners.
Another tactic used to help in the management of moisture and fluids around linear motion components is to add weep holes, drainage channels, slots, or other porting features designed to channel the moisture away from potential pooling areas.
This is an edited article based on the PBC Linear whitepaper, “Linear Motion Design for Washdown Applications.” For more information, visit www.pbclinear.com.
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Features
Maximizing steam turbine/compressor performance with precise torque monitoring at the coupling
Written by PEM Staff Wednesday, 13 March 2013
All turbo machinery is subject to degradation that, over time, will affect the system’s efficiency and operational performance. Precise monitoring of turbo machinery performance with continuous torque-monitoring systems can be used to identify gradual efficiency loss, allowing a more focused maintenance scope to be developed to return the system to its optimum operation and efficiency.
Torque monitoring based on heat balance, energy balance, and other methods utilize numerous parameters such as pressure, temperature, flow rate, gas composition, etc., which require precise instrumentation to properly measure with low uncertainty. However, phase displacement technology can be used to accurately measure torque directly at the coupling to within one per cent of full-scale torque, a combination of all electrical and mechanical sources of error. This accuracy provides the lowest amount of uncertainty when computing efficiency, compared to alternative methods.
A system of this type was recently installed on a cracked-gas compressor train at Qenos Olefins in Australia to determine the causes of a power limitation. The Kop-Flex Powerlign system utilizes phase displacement technology for long-term reliability, eliminating need for re-calibration. Two rings with pickup teeth are installed on a torsionally soft spacer, and are intermeshed at a central location. Two monopole sensors 180 degrees apart are mounted on the coupling guard. As the coupling rotates, the ferromagnetic teeth create an AC voltage waveform in the sensor coil, which is digitally processed using known calibration parameters. Because of the intermeshed pickup teeth, the system is referred to as a single channel phase displacement system, producing two independent torque measurements. The Powerlign system will output torque, power, speed and temperature, which can be easily integrated with any DCS system.
At the Olefins plant the operating cycle of the steam-driven, cracked-gas compressor train is seven to eight years. During this cycle the plant reaches production limitations because this compressor train encounters a power limit. To determine the cause of the power limit as “turbine fouling” or “compressor fouling” or a combination of both was not confidently possible with the instrumentation installed. The cause had long been the subject of an engineering debate between the Machinery group, Process Engineering group and Operations department. One option to add more power by upgrading the turbine power rating from 7.5 MW to 9 MW was investigated. This required a capital investment of $2 million. The plant elected to defer this investment and instead installed a torque meter at the major eight-year shutdown.
The installation involved replacing the existing coupling spacer and flexible halves with a “drop-in” torque meter and integral flexible elements. The torque meter assembly was dynamically balanced to API standards so it was not necessary for the user to return any coupling components for the retrofit. The coupling guard was modified so that the two variable-reluctance sensors could be installed, completing the mechanical installation.
On restarting the plant and having completed a number of compressor efficiency improvements, the torque meter clearly showed the 7.5 MW turbine did not require an uprate and that the major power losses were coming from the compressor. The torque meter also allowed online tuning of the seal gas system of the compressor to establish the lowest power draw from the recycles that the seal system introduces. An additional 200 KW of power was reduced from the turbine load with the manual adjustments made on the seal gas system.
The torque meter is now being used to monitor turbine steam fouling issues and process related compressor fouling so that the corrective online washing can be activated as soon as issues arise.
The historical data collected from the torque meter will also provide a baseline of mechanical loading through the drive drain of the cracked-gas compressor over time. This data will be used to determine if increases in the maximum continuous operating speed rating of the compressor and the turbine can be accomplished at minimal costs. This would achieve increases in the operating envelope of the compressor.
The value of the torque meter has justified the installation of a second system for the Olefins plant’s second steam cracking plant turbine/compressor train in October 2012.
This is an edited article provided by Emerson Industrial Automation. For more information, visit www.emersonindustrial.com.
Torque monitoring based on heat balance, energy balance, and other methods utilize numerous parameters such as pressure, temperature, flow rate, gas composition, etc., which require precise instrumentation to properly measure with low uncertainty. However, phase displacement technology can be used to accurately measure torque directly at the coupling to within one per cent of full-scale torque, a combination of all electrical and mechanical sources of error. This accuracy provides the lowest amount of uncertainty when computing efficiency, compared to alternative methods.
A system of this type was recently installed on a cracked-gas compressor train at Qenos Olefins in Australia to determine the causes of a power limitation. The Kop-Flex Powerlign system utilizes phase displacement technology for long-term reliability, eliminating need for re-calibration. Two rings with pickup teeth are installed on a torsionally soft spacer, and are intermeshed at a central location. Two monopole sensors 180 degrees apart are mounted on the coupling guard. As the coupling rotates, the ferromagnetic teeth create an AC voltage waveform in the sensor coil, which is digitally processed using known calibration parameters. Because of the intermeshed pickup teeth, the system is referred to as a single channel phase displacement system, producing two independent torque measurements. The Powerlign system will output torque, power, speed and temperature, which can be easily integrated with any DCS system.
At the Olefins plant the operating cycle of the steam-driven, cracked-gas compressor train is seven to eight years. During this cycle the plant reaches production limitations because this compressor train encounters a power limit. To determine the cause of the power limit as “turbine fouling” or “compressor fouling” or a combination of both was not confidently possible with the instrumentation installed. The cause had long been the subject of an engineering debate between the Machinery group, Process Engineering group and Operations department. One option to add more power by upgrading the turbine power rating from 7.5 MW to 9 MW was investigated. This required a capital investment of $2 million. The plant elected to defer this investment and instead installed a torque meter at the major eight-year shutdown.
The installation involved replacing the existing coupling spacer and flexible halves with a “drop-in” torque meter and integral flexible elements. The torque meter assembly was dynamically balanced to API standards so it was not necessary for the user to return any coupling components for the retrofit. The coupling guard was modified so that the two variable-reluctance sensors could be installed, completing the mechanical installation.
On restarting the plant and having completed a number of compressor efficiency improvements, the torque meter clearly showed the 7.5 MW turbine did not require an uprate and that the major power losses were coming from the compressor. The torque meter also allowed online tuning of the seal gas system of the compressor to establish the lowest power draw from the recycles that the seal system introduces. An additional 200 KW of power was reduced from the turbine load with the manual adjustments made on the seal gas system.
The torque meter is now being used to monitor turbine steam fouling issues and process related compressor fouling so that the corrective online washing can be activated as soon as issues arise.
The historical data collected from the torque meter will also provide a baseline of mechanical loading through the drive drain of the cracked-gas compressor over time. This data will be used to determine if increases in the maximum continuous operating speed rating of the compressor and the turbine can be accomplished at minimal costs. This would achieve increases in the operating envelope of the compressor.
The value of the torque meter has justified the installation of a second system for the Olefins plant’s second steam cracking plant turbine/compressor train in October 2012.
This is an edited article provided by Emerson Industrial Automation. For more information, visit www.emersonindustrial.com.
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Features
Sorting it Out: Low-friction conveyor components carry benefits in distribution centres
Written by PEM Staff Monday, 10 December 2012
Motion Industries’ two new Canadian distribution centres have no bottling lines, but that didn’t stop the company from adopting a conveyor solution widely used in the bottling industry, where the system’s low-friction components have proven to reduce operating costs. Designed by a Montreal-based original equipment manufacturer (OEM), the new flattop conveyors use System Plast chain and Browning gear drives from Power Transmission Solutions, a division of Emerson Industrial Automation.
The ultra-low-friction conveyor has delivered a range of advantages, including low noise, compactness and low energy use. According to Tom Sawyer, Motion’s distribution centre director, the conveyor is much quieter than a roller conveyor and it has proven reliable, conveying totes without the drift that can occur on a gravity roller conveyor. He says it also demonstrates the plastic chain’s advantages beyond a washdown environment.
Motion Industries Canada opened its two new distribution centres in August 2011, one in Edmonton and another in Montreal, replacing its single centre in Montreal and nearly quadrupling its size to 100,000 square feet. Both facilities have a conventional layout, with shipping and receiving on opposite ends of the building, and shelved inventory in the centre. The shelves branch off at right angles to the shipping conveyor, which runs down the centre of the layout to a 90-degree turn and then to a 180-degree turn leading to five shipping lanes, each for a specific Canadian province.
“Our two [centres] serve our 70 branches in Canada, and we also ship some product directly to customers,” Sawyer explained. “We pick 2,000 to 2,400 lines per day for our branches, and each line may consist of many pieces of a specific product. Our warehouse management software consolidates orders from the branches so our pickers, using RF scanners, can efficiently pick in the same zone for multiple accounts. The product is regrouped in shipment, and a given branch may have several hundred lines going to it every day. We also pick about 200 orders per day for direct shipment to customers.”
Motion’s prior distribution centre used two-level gravity and powered roller conveyor. In the new centre, Motion looked for ways to reduce noise, eliminate maintenance and improve safety.
Motion teamed with a Quebec OEM to design its conveyors. It was decided that the best product for the application was the flattop System Plast conveyor, using XPG chain and Nolu S wear strips. This combination has a coefficient of friction of just 0.16, reducing energy consumption about 25 per cent, compared to standard acetal chain and UHMW-PE wear strips. The XPG chain is also rated for 607 pounds, adequate for the 50-pound maximum tote weight handled at Motion’s facilities.
“This type of belt proved ideal for a compact system layout,” Sawyer explained. “For example, we did a 180-degree turn in a six-foot radius, measured on the outside of the conveyor. This is almost impossible with roller conveyor without transfer tables or pushers. Each of our systems includes a section of about 40 feet of accumulation conveyor with a cleverly designed surface that minimizes load and energy use. We use the accumulation section to spot check our totes for picking accuracy.” Automatic sorting to the shipping lanes is planned for 2012, using scanners and pushers, with manual sortation being used in the short term.
The new conveyor systems use six Browning 575-volt premium efficiency gear motors, with the gearboxes assembled on site at Motion’s DC, which is home to the company’s largest assembly shop in North America. End caps on the motors and bearings protect the rotating shafts. The conveyor requires no compressed air in its accumulation zones and reduces maintenance with the elimination of belt-driven rollers.
“We’ve been surprised by the low noise level of this system, which enhances the workplace, and the conveyor has proven highly reliable,” Sawyer added. “The totes are more secure on the chain than on rollers, much less likely to drift. The chain will actually realign totes slightly, and it easily transports them 175 feet to the first turn.”
This is an edited article provided by Emerson Industrial Automation. For more information, visit www.emersonindustrial.com.
The ultra-low-friction conveyor has delivered a range of advantages, including low noise, compactness and low energy use. According to Tom Sawyer, Motion’s distribution centre director, the conveyor is much quieter than a roller conveyor and it has proven reliable, conveying totes without the drift that can occur on a gravity roller conveyor. He says it also demonstrates the plastic chain’s advantages beyond a washdown environment.
Motion Industries Canada opened its two new distribution centres in August 2011, one in Edmonton and another in Montreal, replacing its single centre in Montreal and nearly quadrupling its size to 100,000 square feet. Both facilities have a conventional layout, with shipping and receiving on opposite ends of the building, and shelved inventory in the centre. The shelves branch off at right angles to the shipping conveyor, which runs down the centre of the layout to a 90-degree turn and then to a 180-degree turn leading to five shipping lanes, each for a specific Canadian province.
“Our two [centres] serve our 70 branches in Canada, and we also ship some product directly to customers,” Sawyer explained. “We pick 2,000 to 2,400 lines per day for our branches, and each line may consist of many pieces of a specific product. Our warehouse management software consolidates orders from the branches so our pickers, using RF scanners, can efficiently pick in the same zone for multiple accounts. The product is regrouped in shipment, and a given branch may have several hundred lines going to it every day. We also pick about 200 orders per day for direct shipment to customers.”
Motion’s prior distribution centre used two-level gravity and powered roller conveyor. In the new centre, Motion looked for ways to reduce noise, eliminate maintenance and improve safety.
Motion teamed with a Quebec OEM to design its conveyors. It was decided that the best product for the application was the flattop System Plast conveyor, using XPG chain and Nolu S wear strips. This combination has a coefficient of friction of just 0.16, reducing energy consumption about 25 per cent, compared to standard acetal chain and UHMW-PE wear strips. The XPG chain is also rated for 607 pounds, adequate for the 50-pound maximum tote weight handled at Motion’s facilities.
“This type of belt proved ideal for a compact system layout,” Sawyer explained. “For example, we did a 180-degree turn in a six-foot radius, measured on the outside of the conveyor. This is almost impossible with roller conveyor without transfer tables or pushers. Each of our systems includes a section of about 40 feet of accumulation conveyor with a cleverly designed surface that minimizes load and energy use. We use the accumulation section to spot check our totes for picking accuracy.” Automatic sorting to the shipping lanes is planned for 2012, using scanners and pushers, with manual sortation being used in the short term.
The new conveyor systems use six Browning 575-volt premium efficiency gear motors, with the gearboxes assembled on site at Motion’s DC, which is home to the company’s largest assembly shop in North America. End caps on the motors and bearings protect the rotating shafts. The conveyor requires no compressed air in its accumulation zones and reduces maintenance with the elimination of belt-driven rollers.
“We’ve been surprised by the low noise level of this system, which enhances the workplace, and the conveyor has proven highly reliable,” Sawyer added. “The totes are more secure on the chain than on rollers, much less likely to drift. The chain will actually realign totes slightly, and it easily transports them 175 feet to the first turn.”
This is an edited article provided by Emerson Industrial Automation. For more information, visit www.emersonindustrial.com.
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Smooth Moves: Conveyor drive system maintenance for heavy-duty material handing
Written by David Keech Tuesday, 09 October 2012
Maintaining the power transmission components of a high capacity, high-power bulk material handing conveyor belt requires treating it as system. This system includes a motor that creates the torque to drive the conveyor, a gearbox to reduce the speed and increases the torque, and a conveyor pulley assembly that transmits the torque to the conveyor belt. These components are connected with high-speed and low-speed couplings.
Replacing components is costly and time consuming, but by scheduling machine downtime to properly maintain each piece of the system, a user can increase the effective long-term life of machinery. Bearings, seals and gears are wear components. This means they will fail — it’s just a matter of when.
Inspecting and observing components should always be included in the preventative maintenance guidelines for a conveyor system. Monitoring lubrication, temperature, noise, vibration, wear and alignment will help uncover potential problems prior to failure.
Routine vibration measurements of the entire equipment train should be taken at regular intervals so that problems can be found well in advance of a component failure. The foundation and equipment base should be checked regularly for movement or looseness.
Motor
The majority of motor failures can be divided into two categories: bearings and windings.
More motors fail due to bearing problems than for any other reason. The leading cause of bearing failures relate to a variety of issues surrounding lubrication. Antifriction bearings should be re-lubricated on a regular basis. The lubrication schedule depends greatly on the motor’s operating environment and service conditions. While failures may occur due to lack of lubrication, bearings may also fail due to grease contaminated by water or other materials.
The second most common cause of motor failures is stator-winding failures. To insure long motor life, it is important the motor operate within the temperature class of its insulation system and be kept clean and free of particle build up on the frame surface, air inlet and fans.
There are several simple tests that can be performed to detect and prevent premature failure of a motor winding. First, motor current can be measured to determine if a motor is overloaded. Measurement of voltage imbalance is the second test. Voltage imbalance between phases may increase motor temperature and cause the motor to exceed rated temperature. The third test uses non-contact infrared pyrometers to help identify potential motor temperature problems by identifying abnormal hot spots, bearing problems, air flow and cooling problems. You can also perform an insulation resistance test. Motor insulation systems may deteriorate because of contamination, mechanical movement, cracking, attack by solvents, mechanical impact, or many other factors.
Technology today also offers the mine engineer sophisticated tools that evaluate the health of a running motor. There are tools available that evaluate the current signature and vibration of a motor concurrently to provide a comprehensive evaluation of motor health. This type of analysis can be performed as a routine survey throughout the mine, or these monitors can be installed on specific critical machines for continuous monitoring. These tools allow the easy transmission of motor data back to motor engineers who can perform a detailed analysis of the data collected from anywhere in the world.
Gearbox
The gearbox is a key component of the conveyor drive and one of the most expensive. Proper lubrication is critical to maintain long-term performance. The oil has two main purposes: it keeps the components from wearing and also keeps them cool.
An oil-sampling program is an effective way to monitor the health of a gearbox. Periodic oil analysis indicates if water is getting into the oil, if the oil is breaking down, or if there is gear or bearing wear. Sampling also can be used to establish oil-change intervals based on the actual condition of the lubricant. When inspecting the gearbox, check for leaks at the shaft seals.
Temperature monitoring is another useful tool. After establishing a baseline, subsequent readings can be used as comparisons, and the data can be trended. A rise in temperature or localized hot spots can indicate problems with the gears or bearings.
A person’s ears are also a useful preventative-maintenance tool. Abnormal sounds are often the first indicator that something is wrong with the gearbox. Vibration readings can be a good indicator of gearbox health, and this analysis can help detect coupling misalignment, improper foundation support (soft foot), and gear or bearing damage. Take a baseline reading with the gearbox installed and connected to the conveyor. Like temperature measurement, trends can help tell what is happening inside the gearbox.
Conveyor Pulley Bearings
Routine maintenance and proper lubrication will ensure a bearing’s maximum life span. The bearings on a conveyor pulley normally run at low speeds and should be filled 100-per-cent full of grease before they leave the factory. This helps prevent water from getting into the bearings during shipping and storage. This fill also helps keep contaminates out during operation.
Effective lubrication is critical to prevent premature bearing failure. If the bearing is not re-lubricated properly then its life is essentially only as good as the service life of the grease. Therefore, re-lubricating the bearing at predetermined intervals is recommended. Most instruction manuals list re-lubrication intervals based upon speed and hours of operation. However, these are typically general recommendations and don’t reflect how temperature and environment may impact the bearing. The manufacturer will be able to supply more detailed recommendations.
When it is time to re-lubricate the bearings, it is important to use with the proper type of lubricant. Not all lubricants, whether grease or oil, are compatible. Contamination, including dirt, dust, moisture, etc., will wreak havoc on a bearing once it has penetrated the seal cavity. It is best to lubricate just before shutdown, especially in moist or humid environments.
Noise and audible vibrations are other easy characteristics to identify. When bearings begin to show audible signs of noise and vibration there is something wrong and a scheduled inspection is due. Vibration is a key characteristic growing in popularity to identify bearing trends and predict failure. Accelerometers can be used to measure vibration on the equipment. Bearing frequencies that correlate with vibration measurements might identify inconsistencies on the raceways or rollers; signs of on setting fatigue failure. Routine measurements should be recorded for future comparisons.
Conveyor Pulley
The pulley needs to be monitored for rim or lagging wear. Typically a pulley is not designed with additional material added for wear. So if the pulley in use on a conveyor is not lagged, and the user is experiencing rim wear, lagging should be applied. However, lagging wear also needs to be monitored because uneven wear can cause problems with belt tracking.
On the drive pulley you can monitor the wear by looking at the depth of the grooves. The grooves are there to allow water and other material that gets between the pulley and the belt to move to the edge of the pulley and out from under the belt. When the grooves are almost gone, or you start to have problems with the belt slipping, it is time to replace the lagging. On non-drive pulleys, the lagging should be replaced before it has worn down to the rim.
The pulley may also be monitored for noise and vibration, which can detect cracks in the rim or end disc.
Couplings
Metallic, grid or gear couplings are most commonly used on large conveyor drives. They require grease lubrication, which should be monitored and changed normally every six to 12 months. Particles found in the grease would indicate the coupling is wearing, typically caused by misalignment. Vibration monitoring of the gearbox can also help determine if there is a problem with misalignment.
Instead of focusing on one or two components of a conveyor system, creating a maintenance program that encompasses the entire system will lead to longer effective life of machinery. Inspecting, observing and caring for the system as a whole will help prevent unplanned downtime and increase productivity.
David Keech is a mining industry engineer with Baldor Electric, a member of the ABB Group. For more information, visit www.blador.com.
Replacing components is costly and time consuming, but by scheduling machine downtime to properly maintain each piece of the system, a user can increase the effective long-term life of machinery. Bearings, seals and gears are wear components. This means they will fail — it’s just a matter of when.
Inspecting and observing components should always be included in the preventative maintenance guidelines for a conveyor system. Monitoring lubrication, temperature, noise, vibration, wear and alignment will help uncover potential problems prior to failure.
Routine vibration measurements of the entire equipment train should be taken at regular intervals so that problems can be found well in advance of a component failure. The foundation and equipment base should be checked regularly for movement or looseness.
Motor
The majority of motor failures can be divided into two categories: bearings and windings.
More motors fail due to bearing problems than for any other reason. The leading cause of bearing failures relate to a variety of issues surrounding lubrication. Antifriction bearings should be re-lubricated on a regular basis. The lubrication schedule depends greatly on the motor’s operating environment and service conditions. While failures may occur due to lack of lubrication, bearings may also fail due to grease contaminated by water or other materials.
The second most common cause of motor failures is stator-winding failures. To insure long motor life, it is important the motor operate within the temperature class of its insulation system and be kept clean and free of particle build up on the frame surface, air inlet and fans.
There are several simple tests that can be performed to detect and prevent premature failure of a motor winding. First, motor current can be measured to determine if a motor is overloaded. Measurement of voltage imbalance is the second test. Voltage imbalance between phases may increase motor temperature and cause the motor to exceed rated temperature. The third test uses non-contact infrared pyrometers to help identify potential motor temperature problems by identifying abnormal hot spots, bearing problems, air flow and cooling problems. You can also perform an insulation resistance test. Motor insulation systems may deteriorate because of contamination, mechanical movement, cracking, attack by solvents, mechanical impact, or many other factors.
Technology today also offers the mine engineer sophisticated tools that evaluate the health of a running motor. There are tools available that evaluate the current signature and vibration of a motor concurrently to provide a comprehensive evaluation of motor health. This type of analysis can be performed as a routine survey throughout the mine, or these monitors can be installed on specific critical machines for continuous monitoring. These tools allow the easy transmission of motor data back to motor engineers who can perform a detailed analysis of the data collected from anywhere in the world.
Gearbox
The gearbox is a key component of the conveyor drive and one of the most expensive. Proper lubrication is critical to maintain long-term performance. The oil has two main purposes: it keeps the components from wearing and also keeps them cool.
An oil-sampling program is an effective way to monitor the health of a gearbox. Periodic oil analysis indicates if water is getting into the oil, if the oil is breaking down, or if there is gear or bearing wear. Sampling also can be used to establish oil-change intervals based on the actual condition of the lubricant. When inspecting the gearbox, check for leaks at the shaft seals.
Temperature monitoring is another useful tool. After establishing a baseline, subsequent readings can be used as comparisons, and the data can be trended. A rise in temperature or localized hot spots can indicate problems with the gears or bearings.
A person’s ears are also a useful preventative-maintenance tool. Abnormal sounds are often the first indicator that something is wrong with the gearbox. Vibration readings can be a good indicator of gearbox health, and this analysis can help detect coupling misalignment, improper foundation support (soft foot), and gear or bearing damage. Take a baseline reading with the gearbox installed and connected to the conveyor. Like temperature measurement, trends can help tell what is happening inside the gearbox.
Conveyor Pulley Bearings
Routine maintenance and proper lubrication will ensure a bearing’s maximum life span. The bearings on a conveyor pulley normally run at low speeds and should be filled 100-per-cent full of grease before they leave the factory. This helps prevent water from getting into the bearings during shipping and storage. This fill also helps keep contaminates out during operation.
Effective lubrication is critical to prevent premature bearing failure. If the bearing is not re-lubricated properly then its life is essentially only as good as the service life of the grease. Therefore, re-lubricating the bearing at predetermined intervals is recommended. Most instruction manuals list re-lubrication intervals based upon speed and hours of operation. However, these are typically general recommendations and don’t reflect how temperature and environment may impact the bearing. The manufacturer will be able to supply more detailed recommendations.
When it is time to re-lubricate the bearings, it is important to use with the proper type of lubricant. Not all lubricants, whether grease or oil, are compatible. Contamination, including dirt, dust, moisture, etc., will wreak havoc on a bearing once it has penetrated the seal cavity. It is best to lubricate just before shutdown, especially in moist or humid environments.
Noise and audible vibrations are other easy characteristics to identify. When bearings begin to show audible signs of noise and vibration there is something wrong and a scheduled inspection is due. Vibration is a key characteristic growing in popularity to identify bearing trends and predict failure. Accelerometers can be used to measure vibration on the equipment. Bearing frequencies that correlate with vibration measurements might identify inconsistencies on the raceways or rollers; signs of on setting fatigue failure. Routine measurements should be recorded for future comparisons.
Conveyor Pulley
The pulley needs to be monitored for rim or lagging wear. Typically a pulley is not designed with additional material added for wear. So if the pulley in use on a conveyor is not lagged, and the user is experiencing rim wear, lagging should be applied. However, lagging wear also needs to be monitored because uneven wear can cause problems with belt tracking.
On the drive pulley you can monitor the wear by looking at the depth of the grooves. The grooves are there to allow water and other material that gets between the pulley and the belt to move to the edge of the pulley and out from under the belt. When the grooves are almost gone, or you start to have problems with the belt slipping, it is time to replace the lagging. On non-drive pulleys, the lagging should be replaced before it has worn down to the rim.
The pulley may also be monitored for noise and vibration, which can detect cracks in the rim or end disc.
Couplings
Metallic, grid or gear couplings are most commonly used on large conveyor drives. They require grease lubrication, which should be monitored and changed normally every six to 12 months. Particles found in the grease would indicate the coupling is wearing, typically caused by misalignment. Vibration monitoring of the gearbox can also help determine if there is a problem with misalignment.
Instead of focusing on one or two components of a conveyor system, creating a maintenance program that encompasses the entire system will lead to longer effective life of machinery. Inspecting, observing and caring for the system as a whole will help prevent unplanned downtime and increase productivity.
David Keech is a mining industry engineer with Baldor Electric, a member of the ABB Group. For more information, visit www.blador.com.
Meet Their Maker: How to ensure a motor’s energy efficiency
Written by David Steen Thursday, 30 August 2012
Since the creation of the first industrial electric motors, manufacturers have been developing technology to produce better motors that use the least amount of energy possible. While perhaps increasing the efficiency of electric motors is not a relatively new phenomenon, the last several decades of technological advancements in motors as well as manufacturing methods have vastly improved their efficiency. As the energy crisis of the 1970s peaked, the manufacturing sector began looking for better ways to save energy. What it discovered was that electric motors were consuming the lion’s share of electricity in industrial facilities. While the news of the day reported about oil shortages and compact-car development, electric motor manufacturers were quietly getting better at producing motors that consumed less electricity.
When these high efficiency and premium efficient motors entered the marketplace, organizations such as NEMA (National Electrical Manufacturers Association) and CEE (Consortium for Energy Efficiency) worked with manufacturers to develop standard levels of efficiency. These standards were later adopted by the U.S.’s Department of Energy (DOE) as the benchmark for the Energy Policy Act of 1992 (EPAct), which went into effect October 1997. This law mandated that general-purpose TEFC (totally enclosed fan cooled) and ODP (open drip proof) motors, one to 200 horsepower (HP), were required to meet the energy efficient table as defined by NEMA MG 1, Table 12-11.
Both the U.S. and Canada require motors to be tested for efficiency in a certified lab using specific test procedures, such as IEEE 112 Method B or CSA 390. Most NEMA members have their test labs certified. Although the IEC test method IEC 60034-2-1 has been harmonized with the IEEE and CSA methods, the E.U. does not require a certified test lab.
The most recent energy law, which broadened the scope of EPAct in the United States, was the Energy Independence and Security Act of 2007 (EISA). This new law went into effect on Dec. 19, 2010. The Canadian version of this law, enacted by Natural Resources Canada (NRCan), went into effect on April 12, 2012. These new laws brought the original one-to-200 HP, 2-4-6 pole motors from the energy efficient levels of table 12-11 up to the premium efficient levels of Table 12-12. A second group of motors was also added under this new legislation, which includes U-frame motors, close-coupled pump motors, footless motors, and eight-pole motors, to name a few.
Understanding the laws and which motors are required to meet them is most of the battle. When one has developed a familiarity with these laws and what they mean, including the motor efficiency tables, it’s a matter of checking this information against the motor manufacturer’s nameplate to identify a motor’s efficiency. It is important to note that if a motor was purchased and installed prior to the implementation of the energy law, the motor only had to meet the requirements of any law in place during the time of installation. If an old motor were to fail, it can be repaired — but one must count the cost and decide if it would be more beneficial to invest the money toward a new, efficient motor. Additionally, if one has a motor in stock that was built prior the energy bill, the motor is also good to use as long as it was in the country prior to the energy bill implementation.
The energy efficiency laws in the U.S. and Canada are for both motors sold in commerce and motors embedded in machinery. If a company is importing a machine using covered electrical motors, those motors must be compliant with the laws. Identifying and understanding the information on motor nameplates can be a bit tricky, especially given the fact all motor nameplates do not always look the same. Two of the main things to look for are the NEMA nominal efficiency and the Certified Compliant (CC) mark for the U.S. and an NRCan mark for Canada. As other countries adopt Minimum Efficiency Performance Standards (MEPS), specific approvals and markings may be required.
The NEMA nominal efficiency is the nominal efficiency as defined by the NEMA tables for a particular motor enclosure, size and speed. This efficiency is expressed in a percentage. For instance, if a motor’s efficiency is labeled as 91-per-cent efficient, then that means the motor will convert 91 per cent of the electrical energy into mechanical energy, resulting in nine per cent of losses due to heat and other factors. For each NEMA nominal efficiency in the tables there is a NEMA guaranteed minimum efficiency based on a 10-per-cent variance in losses as shown in table 12-10. The CC mark is the number provided to each motor manufacturer after their motor line has been approved by the DOE. If this number is not present on the motor, it could be because that particular motor is exempt from law, was built prior to the law, or has not been properly submitted to the DOE for approval. Another distinguishable feature to look for on motor nameplates is the NEMA Premium logo. Although this logo is a registered trademark of NEMA, motor manufacturers can receive the license from NEMA to use this logo on their nameplates and marketing materials. One of the requirements of NEMA Premium usage is for the manufacturer to annually submit their line of motors for efficiency testing to a certified third-party lab facility.
If questions or concerns arise related to identifying the proper motor for an application, especially in regards to efficiency, one should contact their local motor sales representative. Any reputable manufacturer should be more than happy to back up their motor line with whatever data is necessary to demonstrate their performance. As the old saying goes, if something sounds too good to be true, it probably is.
David Steen is a product manager for small/medium AC motors with Baldor, member of the ABB Group. For more information, visit www.baldor.com.
When these high efficiency and premium efficient motors entered the marketplace, organizations such as NEMA (National Electrical Manufacturers Association) and CEE (Consortium for Energy Efficiency) worked with manufacturers to develop standard levels of efficiency. These standards were later adopted by the U.S.’s Department of Energy (DOE) as the benchmark for the Energy Policy Act of 1992 (EPAct), which went into effect October 1997. This law mandated that general-purpose TEFC (totally enclosed fan cooled) and ODP (open drip proof) motors, one to 200 horsepower (HP), were required to meet the energy efficient table as defined by NEMA MG 1, Table 12-11.
Both the U.S. and Canada require motors to be tested for efficiency in a certified lab using specific test procedures, such as IEEE 112 Method B or CSA 390. Most NEMA members have their test labs certified. Although the IEC test method IEC 60034-2-1 has been harmonized with the IEEE and CSA methods, the E.U. does not require a certified test lab.
The most recent energy law, which broadened the scope of EPAct in the United States, was the Energy Independence and Security Act of 2007 (EISA). This new law went into effect on Dec. 19, 2010. The Canadian version of this law, enacted by Natural Resources Canada (NRCan), went into effect on April 12, 2012. These new laws brought the original one-to-200 HP, 2-4-6 pole motors from the energy efficient levels of table 12-11 up to the premium efficient levels of Table 12-12. A second group of motors was also added under this new legislation, which includes U-frame motors, close-coupled pump motors, footless motors, and eight-pole motors, to name a few.
Understanding the laws and which motors are required to meet them is most of the battle. When one has developed a familiarity with these laws and what they mean, including the motor efficiency tables, it’s a matter of checking this information against the motor manufacturer’s nameplate to identify a motor’s efficiency. It is important to note that if a motor was purchased and installed prior to the implementation of the energy law, the motor only had to meet the requirements of any law in place during the time of installation. If an old motor were to fail, it can be repaired — but one must count the cost and decide if it would be more beneficial to invest the money toward a new, efficient motor. Additionally, if one has a motor in stock that was built prior the energy bill, the motor is also good to use as long as it was in the country prior to the energy bill implementation.
The energy efficiency laws in the U.S. and Canada are for both motors sold in commerce and motors embedded in machinery. If a company is importing a machine using covered electrical motors, those motors must be compliant with the laws. Identifying and understanding the information on motor nameplates can be a bit tricky, especially given the fact all motor nameplates do not always look the same. Two of the main things to look for are the NEMA nominal efficiency and the Certified Compliant (CC) mark for the U.S. and an NRCan mark for Canada. As other countries adopt Minimum Efficiency Performance Standards (MEPS), specific approvals and markings may be required.
The NEMA nominal efficiency is the nominal efficiency as defined by the NEMA tables for a particular motor enclosure, size and speed. This efficiency is expressed in a percentage. For instance, if a motor’s efficiency is labeled as 91-per-cent efficient, then that means the motor will convert 91 per cent of the electrical energy into mechanical energy, resulting in nine per cent of losses due to heat and other factors. For each NEMA nominal efficiency in the tables there is a NEMA guaranteed minimum efficiency based on a 10-per-cent variance in losses as shown in table 12-10. The CC mark is the number provided to each motor manufacturer after their motor line has been approved by the DOE. If this number is not present on the motor, it could be because that particular motor is exempt from law, was built prior to the law, or has not been properly submitted to the DOE for approval. Another distinguishable feature to look for on motor nameplates is the NEMA Premium logo. Although this logo is a registered trademark of NEMA, motor manufacturers can receive the license from NEMA to use this logo on their nameplates and marketing materials. One of the requirements of NEMA Premium usage is for the manufacturer to annually submit their line of motors for efficiency testing to a certified third-party lab facility.
If questions or concerns arise related to identifying the proper motor for an application, especially in regards to efficiency, one should contact their local motor sales representative. Any reputable manufacturer should be more than happy to back up their motor line with whatever data is necessary to demonstrate their performance. As the old saying goes, if something sounds too good to be true, it probably is.
David Steen is a product manager for small/medium AC motors with Baldor, member of the ABB Group. For more information, visit www.baldor.com.
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Cut Costs Not Corners: Lubricants have significant impact on energy, labour and equipment costs
Written by Kimberly Eldridge Tuesday, 22 May 2012
How important can the right lubricant be to your company’s bottom line? More than you might think. Because lubricants typically make up only one percent of a company’s total operating costs, many lubrication programs do not receive the attention they deserve. However, the surprising truth is that the lubricants a company chooses can have a significant impact on high-visibility and high-value line items such as energy, labour and equipment costs.
Price versus cost
Identifying the true cost of your lubricant program is the first step in optimizing your plan to positively impact your bottom line. When analyzing your current lubrication program consider how much lubricant you’re using, how often you relubricate, and how much time that relubrication takes. If you already have a handle on these numbers you’re well ahead of the game. If you don’t, take some time to establish a baseline so that when considering alternative products you can conduct an “apples to apples” comparison. By tracking these variables you will come to realize that the true cost of your program includes much more than the price per kilo or price per liter of your lubricants.
Now that you have a firm grasp on the true cost of your company’s lubrication program, the next step is to evaluate where savings are possible. Let’s take a more in-depth look at the factors involved.
Increased productivity
Facilities are constantly pushed to increase productivity while reducing maintenance and operating expenses. Any time your equipment is idle, you’re losing productivity. While some maintenance, including lubrication, can be completed while your line is in operation, some has to be conducted during downtime. This is not a huge inconvenience if you have regularly scheduled downtime that coincides with your relubrication schedule. However, if you have to bring a machine down once a shift specifically to relubricate, that’s money taken away from the bottom line every shift. What if you were using a lubricant that extended that relubrication interval to once a month?
Reducing maintenance costs
If your plant is like most, there is probably a wish list of maintenance projects just waiting for the manpower and time to get them done. While even the best lubricant can’t create time, an optimized lubrication program can help free-up resources to accomplish those tasks. If your lubrication specialist is able to extend relubrication intervals through the use of synthetic, newer-generation products, you can do more with the same staff and with the same time. In our case study, the facility had the potential of reallocating almost 1,500 man-hours annually.
Used-lubricant disposal is also a variable in calculating the costs of your lubrication program. Extended lubrication intervals impact these figures. If you’re using less lubricant, you’re disposing of less lubricant — another savings to the bottom line. And don’t forget your spare parts inventory. Proper lubrication can help your machinery and its components last longer which means less money spent on repairs or rebuilds. Your equipment is a major investment and should be maintained accordingly.
Another factor to consider is how much energy a company can save by utilizing highly efficient gear oils. The right lubricant can reduce the coefficient of friction resulting in less power loss. In other words, the right lubricant requires less energy, leaving you with a lower energy bill at the end of the month.
Lubricants on your line affect your bottom line
In order to avoid the pitfalls of purchasing lubricants based solely on price, evaluate your current program and then request a comparative cost benefit analysis from a supplier. Simple calculations can reveal significant savings that aren’t always evident in the initial cost of a lubricant. n
Kimberly Eldridge is a North American market manager with Klüber Lubrication. For more information, visit www.klueber.com.
Price versus cost
Identifying the true cost of your lubricant program is the first step in optimizing your plan to positively impact your bottom line. When analyzing your current lubrication program consider how much lubricant you’re using, how often you relubricate, and how much time that relubrication takes. If you already have a handle on these numbers you’re well ahead of the game. If you don’t, take some time to establish a baseline so that when considering alternative products you can conduct an “apples to apples” comparison. By tracking these variables you will come to realize that the true cost of your program includes much more than the price per kilo or price per liter of your lubricants.
Now that you have a firm grasp on the true cost of your company’s lubrication program, the next step is to evaluate where savings are possible. Let’s take a more in-depth look at the factors involved.
Increased productivity
Facilities are constantly pushed to increase productivity while reducing maintenance and operating expenses. Any time your equipment is idle, you’re losing productivity. While some maintenance, including lubrication, can be completed while your line is in operation, some has to be conducted during downtime. This is not a huge inconvenience if you have regularly scheduled downtime that coincides with your relubrication schedule. However, if you have to bring a machine down once a shift specifically to relubricate, that’s money taken away from the bottom line every shift. What if you were using a lubricant that extended that relubrication interval to once a month?
Reducing maintenance costs
If your plant is like most, there is probably a wish list of maintenance projects just waiting for the manpower and time to get them done. While even the best lubricant can’t create time, an optimized lubrication program can help free-up resources to accomplish those tasks. If your lubrication specialist is able to extend relubrication intervals through the use of synthetic, newer-generation products, you can do more with the same staff and with the same time. In our case study, the facility had the potential of reallocating almost 1,500 man-hours annually.
Used-lubricant disposal is also a variable in calculating the costs of your lubrication program. Extended lubrication intervals impact these figures. If you’re using less lubricant, you’re disposing of less lubricant — another savings to the bottom line. And don’t forget your spare parts inventory. Proper lubrication can help your machinery and its components last longer which means less money spent on repairs or rebuilds. Your equipment is a major investment and should be maintained accordingly.
Another factor to consider is how much energy a company can save by utilizing highly efficient gear oils. The right lubricant can reduce the coefficient of friction resulting in less power loss. In other words, the right lubricant requires less energy, leaving you with a lower energy bill at the end of the month.
Lubricants on your line affect your bottom line
In order to avoid the pitfalls of purchasing lubricants based solely on price, evaluate your current program and then request a comparative cost benefit analysis from a supplier. Simple calculations can reveal significant savings that aren’t always evident in the initial cost of a lubricant. n
Kimberly Eldridge is a North American market manager with Klüber Lubrication. For more information, visit www.klueber.com.
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Bearing Uptime: Use sight, sound and touch to monitor bearing performance
Written by Galen Burdeshaw Tuesday, 27 March 2012
Bearings are critical components of machines and with proper performance monitoring, imminent failures can be identified and corrected. However, without a monitoring program in place, and subsequent corrective actions taken, a single bearing failure can result in full machine shutdown and countless hours of lost production.
Bearing monitoring is guided by three main senses: sight, sound and touch. Basic monitoring is conducted through elemental observations. However, many highly sensitive tools are available that amplify these observations so they are more noticeable, recordable, and include basic logic to assist with warning identification.
Visual Monitoring
Monitoring bearings visually through classical methods include observing lubricant condition, corrosion, and deterioration. Mounted bearings that are lubricated properly will purge grease from their seals. The condition of the grease upon purging can indicate improper relubrication intervals and/or contamination. Dark, cakey or milky grease are visual signs that relubrication intervals and procedures may be improved.
Evidence of corrosion is a valuable monitoring tool as well. High levels of corrosion can degrade material strength and performance. Deterioration of the surface, seals, or obvious physical dimensional characteristics should also warrant further investigation. These observations are often signals of wear, heat and other abnormal performance prior to total bearing failure.
Several monitoring tools commonly available to leverage visual observations include site gauges for oil lubricated bearings, and thermal imaging guns. Bearings that are lubricated by oil rather than grease are often fitted with site gauges, which will give an indication of the presence of oil and the quantity of oil available to the bearing. These gauges are practical and inexpensive.
Audible Monitoring
Traditionally, audible monitoring is one of the most common methods of monitoring machinery because odd noises are obvious indicators of improper operation, even to the untrained user. It is conducted quickly through an operator’s daily routines. After all, if a bearing within the machine doesn’t sound well it usually isn’t well.
The main problems with bystander audible observations is that (1) it usually identifies the later stages of bearing failure, when planning downtime for bearing replacement is impractical and (2) when audible feedback of a single bearing is masked by the overall noise of its environment. That’s when instruments such as stethoscopes (with amplification) and decibel level meters are advantageous. Both tools are available with a wide range of features that include quantified readings and recording features so bearing performance can be trended. These tools are also more useful at identifying improper operation at a less threatening stage of failure.
Bearings should run quiet and smooth; anything different will likely reflect a flaw or a problem with the bearing itself. Noises such as grinding or banging should be investigated quickly. These noises may indicate complete bearing failure and continued use may lead to catastrophic failure and/or damage to neighboring equipment. Bearing noises such as light clicking and squealing may indicate looseness, faults or skidding and should be inspected for cause and remedy.
Audible evaluation is not as sensitive as other monitoring techniques. It is primarily a method of identifying a failure more so than identifying poor performance. Additionally, audible monitoring in the early stages of failure is more noticeable at higher operating speeds than lower speeds.
Physical (Touch) Monitoring
Monitoring bearings by touch, and then trending the observations against historical performance is by far the most useful and accurate means for assessing bearing condition and predicting bearing failure. The touch method can be used to monitor temperature, vibration, and lubrication.
Operating temperature is the most practical and beneficial monitoring method for bearings because expensive tools are not required and is appropriate to all types of applications; slow to high speeds, light to heavy loads. For example, the average threshold of pain for humans is approximately 130°F. If it is difficult to maintain hand-to-bearing contact for several seconds then the temperature is likely above 130°F. Furthermore, water droplets placed on a bearing housing that quickly boil will indicate that the bearing temperature will have easily exceeded 212°F.
There are also many useful tools available to measure and monitor bearing temperatures. The most common include thermocouples and resistance temperature detectors (RTDs), both of which can be permanently mounted to locations on the bearing housing for continuous real-time monitoring. Temperature switches are also available that can be utilized for warning and/or shutdown at dangerous operating temperatures. Many bearing manufacturers offer various permanently mounted sensors pre-installed in bearing housings in areas that will most accurately reflect the true bearing temperature, rather than the housing skin temperature.
Portable thermal imaging tools are also a quick and efficient means to monitor bearing performance. These tools use infrared thermography to visually identify variations in temperature over a broad area. However, the most common portable temperature measurement tool is the infrared thermometer. Although it does not measure temperatures over a broad area, they are inexpensive and easy to use.
Monitoring and trending bearing temperature is important because as a bearing fails, the temperature will continually increase. Trending temperature over time will help identify a failing bearing in the early stages of failure.
Vibration analysis is the most information-rich method available for bearing analysis, and touch can help identify smooth versus rough operation. As safety permits, feel the housing during operation. Rough operation, jostling, or grinding may indicate a bearing problem.
You may also consider vibration measurement instruments to not only identify stages of bearing failure, but also identify overall machine performance and problems. Sensors mounted to the bearing may include permanently mounted or portable magnetic base accelerometers, displacement probes, or velocity pickups. Sensor selection is dependent upon the bearing speed, sensitivity requirements and the application. Although vibration feedback is highly beneficial, proper training is important due to the complexity in data collection and interpretation.
Simple tests can also be conducted on purged grease to detect hard particle contaminants. Upon relubrication, rub some of the freshly purged grease between fingertips. Gritty grease may indicate a need to lubricate more often or wear from a failing bearing.
Many traditional and advanced options are available to monitor and evaluate bearing performance. Leveraging instrumentation to support traditional observations is a valuable practice in support of a predictive maintenance program.
Galen Burdeshaw is Baldor’s customer order engineering manager for DODGE bearings and power transmission components. For more information, visit www.baldor.com.
Bearing monitoring is guided by three main senses: sight, sound and touch. Basic monitoring is conducted through elemental observations. However, many highly sensitive tools are available that amplify these observations so they are more noticeable, recordable, and include basic logic to assist with warning identification.
Visual Monitoring
Monitoring bearings visually through classical methods include observing lubricant condition, corrosion, and deterioration. Mounted bearings that are lubricated properly will purge grease from their seals. The condition of the grease upon purging can indicate improper relubrication intervals and/or contamination. Dark, cakey or milky grease are visual signs that relubrication intervals and procedures may be improved.
Evidence of corrosion is a valuable monitoring tool as well. High levels of corrosion can degrade material strength and performance. Deterioration of the surface, seals, or obvious physical dimensional characteristics should also warrant further investigation. These observations are often signals of wear, heat and other abnormal performance prior to total bearing failure.
Several monitoring tools commonly available to leverage visual observations include site gauges for oil lubricated bearings, and thermal imaging guns. Bearings that are lubricated by oil rather than grease are often fitted with site gauges, which will give an indication of the presence of oil and the quantity of oil available to the bearing. These gauges are practical and inexpensive.
Audible Monitoring
Traditionally, audible monitoring is one of the most common methods of monitoring machinery because odd noises are obvious indicators of improper operation, even to the untrained user. It is conducted quickly through an operator’s daily routines. After all, if a bearing within the machine doesn’t sound well it usually isn’t well.
The main problems with bystander audible observations is that (1) it usually identifies the later stages of bearing failure, when planning downtime for bearing replacement is impractical and (2) when audible feedback of a single bearing is masked by the overall noise of its environment. That’s when instruments such as stethoscopes (with amplification) and decibel level meters are advantageous. Both tools are available with a wide range of features that include quantified readings and recording features so bearing performance can be trended. These tools are also more useful at identifying improper operation at a less threatening stage of failure.
Bearings should run quiet and smooth; anything different will likely reflect a flaw or a problem with the bearing itself. Noises such as grinding or banging should be investigated quickly. These noises may indicate complete bearing failure and continued use may lead to catastrophic failure and/or damage to neighboring equipment. Bearing noises such as light clicking and squealing may indicate looseness, faults or skidding and should be inspected for cause and remedy.
Audible evaluation is not as sensitive as other monitoring techniques. It is primarily a method of identifying a failure more so than identifying poor performance. Additionally, audible monitoring in the early stages of failure is more noticeable at higher operating speeds than lower speeds.
Physical (Touch) Monitoring
Monitoring bearings by touch, and then trending the observations against historical performance is by far the most useful and accurate means for assessing bearing condition and predicting bearing failure. The touch method can be used to monitor temperature, vibration, and lubrication.
Operating temperature is the most practical and beneficial monitoring method for bearings because expensive tools are not required and is appropriate to all types of applications; slow to high speeds, light to heavy loads. For example, the average threshold of pain for humans is approximately 130°F. If it is difficult to maintain hand-to-bearing contact for several seconds then the temperature is likely above 130°F. Furthermore, water droplets placed on a bearing housing that quickly boil will indicate that the bearing temperature will have easily exceeded 212°F.
There are also many useful tools available to measure and monitor bearing temperatures. The most common include thermocouples and resistance temperature detectors (RTDs), both of which can be permanently mounted to locations on the bearing housing for continuous real-time monitoring. Temperature switches are also available that can be utilized for warning and/or shutdown at dangerous operating temperatures. Many bearing manufacturers offer various permanently mounted sensors pre-installed in bearing housings in areas that will most accurately reflect the true bearing temperature, rather than the housing skin temperature.
Portable thermal imaging tools are also a quick and efficient means to monitor bearing performance. These tools use infrared thermography to visually identify variations in temperature over a broad area. However, the most common portable temperature measurement tool is the infrared thermometer. Although it does not measure temperatures over a broad area, they are inexpensive and easy to use.
Monitoring and trending bearing temperature is important because as a bearing fails, the temperature will continually increase. Trending temperature over time will help identify a failing bearing in the early stages of failure.
Vibration analysis is the most information-rich method available for bearing analysis, and touch can help identify smooth versus rough operation. As safety permits, feel the housing during operation. Rough operation, jostling, or grinding may indicate a bearing problem.
You may also consider vibration measurement instruments to not only identify stages of bearing failure, but also identify overall machine performance and problems. Sensors mounted to the bearing may include permanently mounted or portable magnetic base accelerometers, displacement probes, or velocity pickups. Sensor selection is dependent upon the bearing speed, sensitivity requirements and the application. Although vibration feedback is highly beneficial, proper training is important due to the complexity in data collection and interpretation.
Simple tests can also be conducted on purged grease to detect hard particle contaminants. Upon relubrication, rub some of the freshly purged grease between fingertips. Gritty grease may indicate a need to lubricate more often or wear from a failing bearing.
Many traditional and advanced options are available to monitor and evaluate bearing performance. Leveraging instrumentation to support traditional observations is a valuable practice in support of a predictive maintenance program.
Galen Burdeshaw is Baldor’s customer order engineering manager for DODGE bearings and power transmission components. For more information, visit www.baldor.com.
Published in
Features
Live Long to Prosper: Practical tips from bearing experts to maximize service life
Written by NKE Monday, 05 March 2012
Rolling bearings are high-precision machine elements whose service life directly determines the performance of machines. However, the actual service life is determined by many factors. Premature bearing failures cause costly equipment downtime, sometimes even with very serious consequences. Bearing experts provide some simple yet practical tips to optimize bearing performance.
Start with the right choice
Right from the very beginning, design engineers could enhance the bearing service life by selecting the right bearings for the application. Many factors — such as loads, rigidity, bearing life expectation, operating environment, etc. — need to be considered. Renowned bearing manufacturers have years of experience in different industrial applications. Developing bearing solutions with their assistance can contribute to optimal bearing and equipment service life.
Bearings from renowned manufacturers are produced with the latest technology and undergo stringent quality assurance procedures. Nevertheless, to guarantee the optimum bearing service life, special attention should be made in the following aspects: proper storage, careful mounting and dismounting, adequate lubrication and re-lubrication, appropriate condition monitoring, timely maintenance, and sound personnel training.
Appropriate storage
In principal, all bearings should be stored in their original packaging until being mounted. They should be kept in a clean, non-humid environment at a fairly stable room temperature. Rolling bearings should be stored away from dust, water and aggressive chemicals. Vibrations and shocks could permanently damage the bearings mechanically and therefore must be avoided during handling and storage.
Basically all bearings must be stored flat. Particularly larger and thus heavier bearings might be deformed by their own weight if they are left standing vertically for a long period.
Special care should be taken for the storage of pre-greased (sealed or shielded) bearings. Such grease could change in consistence over a long storage period. This could raise the running noise to a certain extent when put in operation for the first time. Therefore the shelf life of such bearings should be controlled by an FIFO-system (First In First Out).
Cleanliness
Cleanliness is paramount when dealing with rolling bearings. The running surfaces and rolling elements usually have a surface finish roughness of tenths of microns (1/10 µm or 0.0001 mm). Such smooth surfaces are very sensitive to damages by contaminants. The lubrication layer between the running surfaces has usually a thickness between 0.2 to 1.0 µm. Impurities with particle size larger than the lubricants could get over rolled by the rolling elements and thus build up localized stresses in the bearing steel and eventually cause premature material fatigue. Normal environment dust has a grain size of up to 10 µm, which could already damage the bearings.
Therefore, a clean, dust-free environment is extremely important for bearing storage and mounting.
Thorough preparation for mounting
Bearings should be mounted and dismounted carefully by means of appropriate tools. Industry experts estimate that improper fitting causes 16 percent of all premature bearing failures.
For volume mounting in the production assembly the conditions are usually strictly controlled, and the suitable equipment is available for bearing installation. However, for maintenance or replacement work, the environments could vary. Therefore, thorough preparation for bearing fitting is necessary in order to ensure the optimum bearing service life. First of all, the relevant documentation, such as drawings, maintenance manuals, specifications, etc., should be carefully studied. All components, such as shafts, distance rings, housings, cups, flanges, etc., must be thoroughly cleaned and protected from contaminants. The conditions of such adjacent components should also be checked carefully.
Careful mounting and dismounting
Depending on the application, size and type of the bearing, an appropriate mounting method — mechanical, thermal or hydraulic — and tools should be selected. Here are some basic rules for bearing mounting:
Mounting forces should never be applied through rolling elements. This could easily lead to localized overloading in the contact area between the rolling elements and raceways which in turn causes premature bearing failures.
The bearing surfaces should never be hit directly with any hardened tools such as hammers, cotter pin drives, etc. This could cause a breakage or fragmenting of the bearing rings.
The instructions from the respective mounting equipment supplier should always be followed.
About 90 percent of rolling bearings are never removed from the equipment where they are built in. Usually only the larger bearings would be removed as part of the scheduled preventive maintenance programs. Same as mounting a bearing, dismounting should also be thoroughly prepared. During the dismounting, ensure the adjacent components such as the shaft or housing are not damaged. Appropriate methods and tools should be used for dismounting, depending on the bearing type, size and application.
Appropriate lubrication
The lubricant separates the metallic bearing surfaces such as rolling elements, rings, and cages and thereby reduces friction, preserves the metal parts and guards off contaminants and impurities. A wide range of lubricants — including grease, oil, and solid — is available for different operating conditions. The correct selection of lubricant is crucial to ensure optimal bearing and equipment service life.
Bearing lubricants undergo permanent mechanical stressing caused by the over-rolling of rolling elements. Moreover, lubricants change their chemical properties over time, particularly at high operating temperatures and in humid or polluted environments. All these lead to a gradual loss of lubricating quality.
Therefore bearings have to be re-lubricated at regular intervals to ensure maximum service life. The re-lubrication interval depends on operating conditions such as temperatures, running speeds, loads, environment, etc.
Only in case of pre-greased bearings (shielded or sealed bearings), i.e. “greased-for-life” bearings, the bearing service life is determined by the lubricant service life span.
Lubricants must be stored properly according to manufacturers’ instructions. Particular attention must be paid to keep the lubricant clean from any contamination. Prior to each application, the condition of the lubricant should be checked carefully.
Condition monitoring and maintenance
Generally rolling bearings are extremely reliable although they do not have an indefinite life. Like all other important components in the machinery, they should be inspected and maintained regularly. How often the inspections and maintenance should be carried out depends on the importance of the particular application and operating conditions of the individual equipment.
For bearing arrangements with critical functions, it is advisable to incorporate a condition monitoring feature at the design stage. Important parameters of the machine operation such as vibration and noise can be monitored continuously. Preventive measures could be planned before breakdowns.
Training
Practice makes perfect. But proper training provides the basis for the practice. Reputable bearing manufacturers offer various training programs for commercial, technical and workshop staff. Costly human errors can be avoided if maintenance technicians possess fundamental knowledge in handling bearings. Design and product development engineers can maximize the equipment performance and minimize life-cycle costs by optimal design of bearing locations.
Bearings are often critical components in all machines. Proper storage, careful mounting and dismounting, adequate lubrication and re-lubrication, appropriate condition monitoring, timely maintenance and, last but not least, sound personnel training are essential to improve bearing service life, and therefore enhance equipment performance.
This is an edited article provided by NKE, which is distributed in Canada through Global Bear Inc. For more information, visit www.globalbear.ca.
Start with the right choice
Right from the very beginning, design engineers could enhance the bearing service life by selecting the right bearings for the application. Many factors — such as loads, rigidity, bearing life expectation, operating environment, etc. — need to be considered. Renowned bearing manufacturers have years of experience in different industrial applications. Developing bearing solutions with their assistance can contribute to optimal bearing and equipment service life.
Bearings from renowned manufacturers are produced with the latest technology and undergo stringent quality assurance procedures. Nevertheless, to guarantee the optimum bearing service life, special attention should be made in the following aspects: proper storage, careful mounting and dismounting, adequate lubrication and re-lubrication, appropriate condition monitoring, timely maintenance, and sound personnel training.
Appropriate storage
In principal, all bearings should be stored in their original packaging until being mounted. They should be kept in a clean, non-humid environment at a fairly stable room temperature. Rolling bearings should be stored away from dust, water and aggressive chemicals. Vibrations and shocks could permanently damage the bearings mechanically and therefore must be avoided during handling and storage.
Basically all bearings must be stored flat. Particularly larger and thus heavier bearings might be deformed by their own weight if they are left standing vertically for a long period.
Special care should be taken for the storage of pre-greased (sealed or shielded) bearings. Such grease could change in consistence over a long storage period. This could raise the running noise to a certain extent when put in operation for the first time. Therefore the shelf life of such bearings should be controlled by an FIFO-system (First In First Out).
Cleanliness
Cleanliness is paramount when dealing with rolling bearings. The running surfaces and rolling elements usually have a surface finish roughness of tenths of microns (1/10 µm or 0.0001 mm). Such smooth surfaces are very sensitive to damages by contaminants. The lubrication layer between the running surfaces has usually a thickness between 0.2 to 1.0 µm. Impurities with particle size larger than the lubricants could get over rolled by the rolling elements and thus build up localized stresses in the bearing steel and eventually cause premature material fatigue. Normal environment dust has a grain size of up to 10 µm, which could already damage the bearings.
Therefore, a clean, dust-free environment is extremely important for bearing storage and mounting.
Thorough preparation for mounting
Bearings should be mounted and dismounted carefully by means of appropriate tools. Industry experts estimate that improper fitting causes 16 percent of all premature bearing failures.
For volume mounting in the production assembly the conditions are usually strictly controlled, and the suitable equipment is available for bearing installation. However, for maintenance or replacement work, the environments could vary. Therefore, thorough preparation for bearing fitting is necessary in order to ensure the optimum bearing service life. First of all, the relevant documentation, such as drawings, maintenance manuals, specifications, etc., should be carefully studied. All components, such as shafts, distance rings, housings, cups, flanges, etc., must be thoroughly cleaned and protected from contaminants. The conditions of such adjacent components should also be checked carefully.
Careful mounting and dismounting
Depending on the application, size and type of the bearing, an appropriate mounting method — mechanical, thermal or hydraulic — and tools should be selected. Here are some basic rules for bearing mounting:
Mounting forces should never be applied through rolling elements. This could easily lead to localized overloading in the contact area between the rolling elements and raceways which in turn causes premature bearing failures.
The bearing surfaces should never be hit directly with any hardened tools such as hammers, cotter pin drives, etc. This could cause a breakage or fragmenting of the bearing rings.
The instructions from the respective mounting equipment supplier should always be followed.
About 90 percent of rolling bearings are never removed from the equipment where they are built in. Usually only the larger bearings would be removed as part of the scheduled preventive maintenance programs. Same as mounting a bearing, dismounting should also be thoroughly prepared. During the dismounting, ensure the adjacent components such as the shaft or housing are not damaged. Appropriate methods and tools should be used for dismounting, depending on the bearing type, size and application.
Appropriate lubrication
The lubricant separates the metallic bearing surfaces such as rolling elements, rings, and cages and thereby reduces friction, preserves the metal parts and guards off contaminants and impurities. A wide range of lubricants — including grease, oil, and solid — is available for different operating conditions. The correct selection of lubricant is crucial to ensure optimal bearing and equipment service life.
Bearing lubricants undergo permanent mechanical stressing caused by the over-rolling of rolling elements. Moreover, lubricants change their chemical properties over time, particularly at high operating temperatures and in humid or polluted environments. All these lead to a gradual loss of lubricating quality.
Therefore bearings have to be re-lubricated at regular intervals to ensure maximum service life. The re-lubrication interval depends on operating conditions such as temperatures, running speeds, loads, environment, etc.
Only in case of pre-greased bearings (shielded or sealed bearings), i.e. “greased-for-life” bearings, the bearing service life is determined by the lubricant service life span.
Lubricants must be stored properly according to manufacturers’ instructions. Particular attention must be paid to keep the lubricant clean from any contamination. Prior to each application, the condition of the lubricant should be checked carefully.
Condition monitoring and maintenance
Generally rolling bearings are extremely reliable although they do not have an indefinite life. Like all other important components in the machinery, they should be inspected and maintained regularly. How often the inspections and maintenance should be carried out depends on the importance of the particular application and operating conditions of the individual equipment.
For bearing arrangements with critical functions, it is advisable to incorporate a condition monitoring feature at the design stage. Important parameters of the machine operation such as vibration and noise can be monitored continuously. Preventive measures could be planned before breakdowns.
Training
Practice makes perfect. But proper training provides the basis for the practice. Reputable bearing manufacturers offer various training programs for commercial, technical and workshop staff. Costly human errors can be avoided if maintenance technicians possess fundamental knowledge in handling bearings. Design and product development engineers can maximize the equipment performance and minimize life-cycle costs by optimal design of bearing locations.
Bearings are often critical components in all machines. Proper storage, careful mounting and dismounting, adequate lubrication and re-lubrication, appropriate condition monitoring, timely maintenance and, last but not least, sound personnel training are essential to improve bearing service life, and therefore enhance equipment performance.
This is an edited article provided by NKE, which is distributed in Canada through Global Bear Inc. For more information, visit www.globalbear.ca.
As the busiest port on the Canadian side of the Great Lakes-St. Lawrence Seaway navigation system, the Port of Hamilton plays an integral role in supporting trade between Canada and the U.S. as well as overseas destinations. With thousands of jobs dependent on the cargo that is transported in and out of this port, one 12-person maintenance team is responsible for ensuring a variety of buildings, warehouses and infrastructure remain in good working order year-round.Check out the full story in the March/April 2013 issue of PEM.
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