A plant engineer’s ability to diagnose, detect and monitor equipment condition issues is advancing all the time, thanks to ongoing developments with vibration, thermography (infrared), oil analysis and ultrasound tools, just to name a few.

So once you have all the fancy new tools, do you know how best to take advantage of them?

We’re here to help. Along with the sophistication of the tools available, ways to synthesize and integrate data so that maintenance teams can make immediate use of it and also monitor trend issues over a period of time are also progressing. PEM asked leading technology providers to share the latest in their condition monitoring tech developments, how best to integrate them, and where the future is headed.

Infrared
Over the last few years, infrared cameras have improved significantly in terms of resolution and now come with more options as well, says Paul Frisk, manager of the Infrared Training Center in Burlington, Ont. (the training arm of infrared camera-maker FLIR Canada Ltd.). “Infrared cameras now have the ability to incorporate wireless data from digital clamp meters and other instruments and make that all available at one glance,” he explains. “Some cameras now available immediately generate a single-page report. This summary can be transferred for printing and archiving by download to an office computer or through wifi to a plant’s CMMS system.”

Frisk says the primary value of an infrared camera is in its ability to initially determine whether a device is working properly or not while it’s running. “With some other diagnostic tools, you have to shut down the device, which obviously impacts production,” he notes. However, as with many types of detection and monitoring technology, there are misconceptions about what infrared cameras can provide.

“From watching movies and TV, people think infrared cameras can allow you to see through walls, water, etc., but they only measure released infrared energy,” he explains. “A properly trained thermographer can determine temperatures from infrared readings using conversion factors, knowing the material and so on, but infrared cameras cannot overcome the physics of all materials under all conditions.” He also stresses that infrared images can easily be misinterpreted, and proper training is absolutely necessary.

In addition to using handheld infrared cameras and connecting them with your plant’s CMMS, standalone infrared cameras can send data to the process PLC (programmable logic controller). “Based on the camera’s readings, things like process speed, fans or heat can automatically be adjusted if the material needs to be kept at a certain temperature,” Frisk notes.

With regard to the future of infrared condition monitoring technology, he foresees more improvement in resolution and smaller camera size, along with a continued drop in cost.

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Ultrasound
Ultrasound instruments have changed a great deal over the past decade, according to Alan Bandes, vice president of marketing at UE Systems. Analog detectors, which required manual entry of test results for basic trouble-shooting, have been replaced by software-driven digital systems capable of analyzing trends and reporting on a wide range of operating conditions. Newer models offer things like sound analysis, cameras, non-contact infrared thermometers, and even touch screen controls. “There are a lot of professionals that haven’t looked at ultrasound technology closely and view the instruments as basically leak detectors,” Bandes says. “Others feel, incorrectly, that ultrasound is too subjective, which is often due to experience only with older analog units.”

Bandes says it’s very easy to integrate ultrasound technology into plant processes. “Due to the sophistication of on-board software and external supportive software, users can create routes, establish baseline information and upload and download route data,” he explains. With baselines set, the software can notify personnel with low-level alarms (for example, lubrication starvation) or high alarms (failure) through headphones or other means.

Some instruments provide inspectors with the option of opening up a spectral analysis screen to analyze bearing faults, gear mesh issues and electric emissions while in the field. Recorded sound samples can be played in real-time and viewed with an image of the spectral screen. “This feature is very useful for electrical emissions as well as mechanical operations,” he notes.

Software associated with ultrasound instruments can provide specialized reporting for things like steam traps, valves and bearings. “Regarding leak surveys, downloaded test results can be converted into reports that provide important information for cost analysis and greenhouse gas emissions,” Bandes says. Regarding the future of machine monitoring by ultrasound, he believes “we are only limited by the software we can develop.”

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Oil analysis
More vendors now supply in-plant oil analysis sensors and the means to communicate with those sensors. “It's no longer necessary to rely solely on a lab for analyzing oil samples to determine fluid condition,” says Darren German, Bosch Rexroth national service manager. “In the plant, we can now get real-time results on of oil cleanliness (particle count), water content and temperature when sensors are coupled with a data acquisition device.” These devices can record and track trend parameters in real time for any given time period, but German cautions maintenance teams that monitoring equipment should be considered as a compliment to a bottle sampling program; reports from an oil analysis lab still provide the most oil condition information. The role of monitoring equipment is to provide additional protection between bottle sampling periods, he says. “If, for example, a heat exchanger ruptures and releases water into the oil the day after a bottle sample was taken,” he notes, “this will likely go unnoticed until production stops if there is no oil analysis sensors in place.”

The many oil-monitoring systems on the market range in complexity and price. “Some of the data acquisition systems also provide the ability to add a threshold or alarm which will signal the moment the results vary from a ‘baseline normal,’ ” he says. “We suggest that before investing, you should understand what it is that you want to accomplish — what parameters are important to monitor.” He recommends that maintenance groups consult with their engineering groups prior to purchasing a system, as the ability for a machine to communicate with a sensor often already exists within the machine HMI.

German predicts that down the road, the capacity to measure reliable viscosity and TAN (total acid number) will be developed, along with a sensor that can measure the amount of air in hydraulic fluid. “ ‘Smart’ sensors and wireless sensors are often mentioned as coming down the pipe as well,” he says.

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Vibration
Advances over the last few years in sensor, recording, and analysis technology have put vibration analysis within the reach of even small companies, says John Bernet, product and application specialist at Fluke Corp. “Easier measurement procedures (triaxial sensors), combined with vibration diagnosis programs (expert systems) now enable maintenance teams with minimal training and experience to use vibration to evaluate machine health and determine required maintenance,” he notes.

Bernet says vibration can identify problems before other symptoms, such as heat, sound, electrical consumption and lubricant impurities, are detected. “Measuring the vibration of motors, pumps, and other common machines can reveal valuable information about machine health or impending failures,” he notes. “However, instead of focusing on the patterns of the hundreds of faults that vibration analysis can reveal, we should focus on the four most common mechanical faults: imbalance, misalignment, wear, and looseness.” He adds that studies have found that many vibration analysis programs don’t collect all the data needed to make an accurate diagnosis — to diagnose machine condition correctly, vibration data is needed from all three axes of a rotating shaft.

The key to automating vibration analysis, he notes, is to compare new data with data from a similar machine known to be functioning properly. Automated diagnostic programs perform a sophisticated analysis, comparing hundreds of data points with the fault patterns of similar machines to give easy-to-understand results.

Bernet foresees that the benefits of vibration analysis will be expanded to the entire plant in future. “A plant’s reliability team can use high-end analysis programs on the few complex machines, while the maintenance team can use simple diagnostic tools on the basic machines,” he says.  p

Treena Hein is a freelance writer based in Pembroke, Ont.

Introducing the newest member to round out the family: the AS series from Rexroth is now available in a smaller version for lower flows with thread connection G1/4.

With its smallest version, Rexroth has expanded the AS line for compressed air preparation. The system, which provides excellent compressed air quality in a wide variety of applications and work environments, now includes the AS1 series for use in the low flow range.

With a width of 43 mm and connection thread G1/4, the AS1 series is virtually predestined for applications with flow requirements up to 1000 std l/min. Like the larger members of the AS series, the AS1 also stands for reliable, safe, and economical operation on a continuous basis.

These maintenance units not only perform the standard functions of filtering, regulation and lubrication, their modular and compact design further allows for the integration of all specific functions. Precision controllers, distributors, 3/2-way shut-off valves and filling valves round out the product range of maintenance units. This allows an optimum customized solution for each application. Modular construction makes it possible for individual components to be disassembled or subsequent extensions to be carried out as needed, even in the installed state.
www.boschrexroth.ca

The new PGZ Series 1X gerotor pump from Bosch Rexroth represents a pump concept for low-pressure applications in the nominal size range from 20 to 140 ccm. Use in variable-speed drives is assured by a wide speed range from 200 to 3,000 rpm. The new PGZ Series 1X gerotor pump is designed in particular for cooling, filtering and lubricating circuits with low operating pressures up to 15 bar in industrial and mobile applications, such as plastic processing machines, machine tools, presses and wind power plants.
www.boschrexroth.ca

The drive power transmission of production machinery may essentially be achieved via one of three technologies: mechanical, electrical or fluidic. Each technology has distinct advantages and disadvantages; however, it is not necessary to cover each of these in this article.

The losses in fluid power/hydraulic energy transmission can typically be classified as either conversion losses or transmission/control losses. Hydraulic-equipment manufacturers have continuously improved the design of their components with an eye toward increasing overall efficiencies; however, improvements in this area tend to follow the law of diminishing returns as componentry achieves ever-higher efficiency levels. Circuit technology has also changed over the years, and devices — such as variable displacement pumps with load sensing and electronic controllers — have helped achieve significant overall system efficiency gains. Below, we’ll discuss how additional efficiency gains can be achieved by combining the advantages of different drive technologies.

Historically, a typical arrangement in most hydraulic systems is a fixed-speed electric motor driving a variable-displacement hydraulic pump, which matches its output to the flow requirements of the system. In recent years, there has been interest in using variable-speed electric drives and fixed-displacement hydraulic pumps to achieve the same end. The advantage of this drive alternative is twofold: there is less energy consumption due to operating the pump and motor at a point where maximized efficiencies are achieved; and noise is reduced due to lower motor-drive speeds. A study is currently underway at a Canadian wood mill to investigate the possible savings that can de derived by using variable-speed electric servo drives and high-efficiency fixed-displacement hydraulic pumps and accumulators to replace systems currently utilizing fixed-speed asynchronous motors and pressure-compensated piston pumps. Currently, the hydraulic system consists of four 75-kW, 1,800-RPM high-efficiency motors driving pressure-compensated axial piston pumps at a pressure level of 150 bar. The machines operate 24 hours per day, five days per week.

Because the work is being performed on an existing system, we needed to benchmark its operation; therefore, data acquisition was installed to record the pressure and flow requirements during normal machine cycles. With this information, it was possible to make models of the system demands and run simulations of various machine cycles to compare operational costs using various drive technologies. When comparing the existing systems to other possible solutions, it was found that a variable-speed pump (VSP) drive offered the highest energy savings.

First, during steady-state production, the following table shows energy consumption comparisons between the original pressure-compensated pumps/fixed-speed electric motors and the new VSP drive.

(Click images to expand.)

The pressure control mode of the operation is accomplished via an algorithm inside the servo control, which adjusts motor speed in relation to the difference between commanded and actual pressure values. Therefore, when the system is not consuming any flow (pressure holding mode), the drives can be operating at nearly zero speed.

While the initial system cost is slightly higher for this new technology, the return on investment can be relatively short when considering the potential energy savings (which can be around 25 percent).

Higher gains can be achieved in systems where the pump is utilized as primary control, whereby it is providing direct control of an actuator. In cases such as these, the electric servo drive can reverse its rotation and consume power back out of the hydraulic system.

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Doug Wilson is the fluid-power training manager with Bosch Rexroth Canada. For more information, visit www.boschrexroth.ca.

Bosch Rexroth Canada, a provider of drive and control solutions, celebrated its 50th anniversary last month.

Originally founded in the Welland, Ont., area in June 1961 as Basic Structure Steel Fabricators Ltd., Bosch Rexroth Canada has since grown to employ more than 300 associates in nine locations across Canada.

“The key to our success over the years has always been the creativity of our people in solving our customers’ problems using innovative technologies,” said company president Thomas Light. “It’s both personally and professionally rewarding to be part of this outstanding tradition.”

The company got its start in hydraulics technologies in the mid 1960s through the development of the “UpPUP” telescopic work platform. The company’s name changed to Basic Hydraulics and Industrial Equipment Ltd. around this time. One of Basic’s staff engineers recommended hydraulic components from the German hydraulics company, G.L. Rexroth GmbH, and in 1968 Basic became Rexroth’s sole authorized Canadian distributor. As Rexroth added new drive and control technologies to its portfolio, Basic adapted also, changing its name to Basic Technologies Corp. to reflect the more comprehensive product portfolio. Rexroth acquired a significant equity stake in the company in 1996, and followed that by acquiring a majority stake in 2001. Following the Rexroth acquisition by Robert Bosch GmbH, the company was renamed Bosch Rexroth Canada Corporation. Today, the company continues its mission of supplying drive and control technologies and system solutions throughout Canada.
www.boschrexroth.ca