Grease lubrication of rolling element bearings is one of the most common lubricated scenarios in industry. The exact
behavior of greases while equipment is in operation is not well understood. This paper will detail studies that provide
insight into the thermal behavior, flow characteristics of the non-newtonian greases, and changes in grease properties in
operating rolling-element bearings.
Infrared technology has seen little use at the level of the family farm, mostly due to the prohibitive high cost relative to the typically modest profit margins. Where farming exists as a hobby or secondary activity, an individual with access to the technology can uncover some of the many applications waiting to be discovered in this field. As technology improves, and the price of cameras decreases, the viability of infrared as a farming tool improves.
This paper outlines a number of examples where an individual with access to infrared technology has utilized it in a family farm setting to highlight some of the potential uses which may someday become normal farming practice. These examples are augmented by research of work being done at land-grant universities and larger agricultural businesses that further show the viability of the technology in farming.
Industrial and commercial building equipment maintenance has not historically been targeted for implementation of PdM programs. The focus instead has been on manufacturing, aerospace and energy industries where production interruption has significant cost implications. As cost-effectiveness becomes more pervasive in corporate culture, even office space and labor activities housed in large facilities are being scrutinized for cost-cutting measures. When the maintenance costs for these facilities are reviewed, PdM can be considered for improving the reliability of the building temperature regulation, and reduction of maintenance repair costs. An optimized program to direct maintenance resources toward a cost effective and pro-active management of the facility can result in reduced operating budgets, and greater occupant satisfaction.
A large majority of the significant rotating machinery in a large building environment are belt-driven air handling units. These machines are often poorly designed or utilized within the facility. As a result, the maintenance staff typically find themselves scrambling to replace belts and bearings, going from one failure to another. Instead of the reactive-mode maintenance, some progressive and critical institutions are adopting predictive and proactive technologies of infrared thermography and vibration analysis. Together, these technologies can be used to identify design and installation problems, that when corrected, significantly reduce maintenance and increase reliability. For critical building use, such as laboratories, research facilities, and other high value non-industrial settings, the cost-benefits of more reliable machinery can contribute significantly to the operational success.
On-line equipment condition monitoring is a critical component of the world-class production and safety histories of many successful nuclear plant operators. From addressing availability and operability concerns of nuclear safety-related equipment to increasing profitability through support system reliability and reduced maintenance costs, Predictive Maintenance programs have increasingly become a vital contribution to the maintenance and operation decisions of nuclear facilities. In recent years, significant advancements have been made in the quality and portability of many of the instruments being used, and software improvements have been made as well. However, the single most influential component of the success of these programs is the impact of a trained and experienced team of personnel putting this technology to work. Changes in the nature of the power generation industry brought on by competition, mergers, and acquisitions, has taken the historically stable personnel environment of power generation and created a very dynamic situation. As a result, many facilities have seen a significant turnover in personnel in key positions, including predictive maintenance personnel. It has become the challenge for many nuclear operators to maintain the consistent contribution of quality data and information from predictive maintenance that has become important in the overall equipment decision process. These challenges can be met through the implementation of quality training to predictive maintenance personnel and regular updating and re-certification of key technology holders. The use of data management tools and services aid in the sharing of information across sites within an operating company, and with experts who can contribute value-added data management and analysis. The overall effectiveness of predictive maintenance programs can be improved through the incorporation of newly developed comprehensive technology training courses. These courses address the use of key technologies such as vibration analysis, infrared thermography, and oil analysis not as singular entities, but as a toolbox resource from which to address overall equipment and plant reliability in a structured program and decision environment.
Infrared imaging of the discharge canal and intake pond of the Peach Bottom Atomic Power Station was initiated to confirm a plant staff suspicion that high water intake temperatures were being influenced by recirculation of discharge flow. To minimize the angle of incidence to the water surface, the inspection was made from the top of the cooling towers. Although there was no evidence of recirculation from the plant discharge to the intake pond, two unexpected inputs of thermal energy were discovered during the inspection. A faulty sluice gate and a damaged cross-around pipe could be seen to be dumping thermal energy into the intake pond. The result was increased temperatures at the intake which threatened plant operation, decreased plant efficiency, and resulted in fewer megawatts available to sell to customers during the critical summer months.
Predictive Maintenance programs have been shown to be an effective and efficient approach to managing facilities maintenance. Cost savings through the reduction of time- based preventive tasks, and the reduction of unanticipated failures can be significant. Several inspection techniques have become standard, and are applicable to a broad range of equipment types and inspection scenarios. IR thermography of fan and compressor equipment presents a significant opportunity for cost saving applications in may facilities. Ventilation systems supply air to and remove air from working spaces, and mitigate environmental conditions for a number or purposes. Removal of hazardous pairs or gases, positive pressure atmosphere, or negative pressure atmosphere are a few examples. Vaneaxial fans are a common equipment type used to achieve this purpose. Both direct drive and belt driven fans are common for these systems. Belt drives present some unique imaging applications, where sheave and belt surface scan be observed. Compressor equipment has normally high operating temperatures, relative to other rotating equipment. The compression of gases is exothermic, and as a result, most compressors rely on an integral cooling process to function properly. Uniformity of temperature distribution on equipment surfaces, function of cooling systems, and verification of proper operation of loading and relief valves provide an overall illustration of equipment health.
For large scale chicken and turkey raising operations, automated 'candling' of eggs for monitoring embryonic development is effective and efficient. Candling is accomplished by the transmission of high intensity light such that it penetrates the translucent egg and gives indications of embryonic position and development. When monitoring the development of other species, however, mixed results are obtained with this technique. For instance, the Emu egg is virtually opaque to transmitted visible light, and thus cannot be candled by traditional means. During the development cycle all avian embryos, and for that mater all egg-laying creatures, exhibit changes in shell surface temperatures that indicate on-going development, or a lack of that development. Additionally, such hazards as bacterial or viral growth within the shell produce atypical thermal signatures. Analysis of the shell surface temperatures may be useful in monitoring the development of these embryos. Further applications of IR thermography in farming of avian species may make it an economically viable monitoring technique.
As today's marketplace becomes more competitive, companies are continually searching for more efficient ways to maintain plant equipment. As a result, predictive maintenance (PDM) techniques are frequently utilized to help reduce maintenance costs and increase equipment reliability. Two PDM technologies that have enjoyed widespread success in many different industries are lubricant analysis and infrared thermography. Lubricant analysis is a very effective technique in the identification of both machine and lubricant deficiencies. Problems such as bearing wear, gear wear, lubricant contamination and degradation are identified utilizing technologies like ferrography and physical properties testing. Infrared thermography has likewise enjoyed much success in various electrical, mechanical, and process applications. High resistance electrical connections, excessive friction, insulation degradation, and roofing deterioration are just a few of the more common problems detectable utilizing infrared thermography. Although each PDM technology has its own distinct area of specialization, the greatest benefits come from the integration of each technology into a comprehensive PDM program. This paper focuses on the interrelationship between lubricant analysis and infrared thermography and successful applications where these two PDM technologies have been used together to identify and solve equipment specific problems.
Justifying the costs of starting and maintaining an in-house IR thermography program is essential in ensuring continued funding and sponsorship. Cost benefit studies, whether brief and general, or strictly formalized, tend to focus on costs associated with projected equipment failure and production downtime. While these numbers can be quite dramatic, their validity rests on acceptance of the predicted failure which is inevitably the subject of some conjecture.
In the Nuclear Power Generation Industry, Emergency Diesel Generators are a critical component in ensuring the ability to safely operate the plant. Relegated to a standby role, this equipment must be immediately available to provide power to important plant equipment needed to safely shutdown the reactor, in the event of a loss of normal off-site sources of power. Consequently, maintenance, operation, and surveillance of these generators is performed under close scrutiny, and any deviations from established parameters can potentially lead to the mandatory shutdown of the reactor, and subsequent loss of power generation revenue. At Peach Bottom Atomic Power Station, Thermographic Inspection has become an integral part of the operation of the Diesel Generators. Generators are operated according to the required surveillance tests, and a Thermographic Inspection is made at least twice a year. Some of the applications include checking for exhaust leaks, generator end bearing and cylinder exhaust temperatures, observing the effects of thermal mixing between crosstied cooling systems, and other mechanical and electrical troubleshooting.
Performing a complete thermographic survey for a utility, process plant, etc. involves looking at hundreds of components. Generally, they are multiple pieces of identical equipment which operate simultaneously, and the redundancy allows for comparative evaluation between these pieces of equipment. When performing this evaluation with thermography, valuable information can be obtained for a predictive maintenance program. Some applications exist where quantitative data is not required to diagnose and recommend appropriate corrective action. In these cases, qualitative techniques may be adequate in providing the needed information. Most applications, however, require assigning values to observed thermal patterns for the purposes of trending, designating severity levels, and assigning priorities. In these cases, comparative thermography can be used to provide the best available data in lieu of ideal thermal measurement capabilities. Changing load considerations, techniques in performing rough emissivity estimates, and the ability to differentiate emissivity differences on energized or rotating equipment give the predictive maintenance engineer the ability to provide useful information under the less—than—ideal circumstances frequently encountered in the field.
Following a series of failures of the lubricated couplings of the Reactor Feedpumps at the Peach Bottom Units 2 and 3, thermographic monitoring of these couplings was initiated. Baseline data was collected for all six feedpumps and a monitoring frequency was established. Data was collected over a three month period, and a trend-to-failure was developed both qualitatively and quantitatively. The motion of the coupling was effectively strobed by the infrared camera to allow the interpretation of heat patterns on the coupling surface. By keeping stored infrared images and comparing them to the as-found condition during coupling inspections, it became possible to identify heat patterns that were characteristic of lubricant degradation of coupling tooth breakage situations. In addition, data was compared to certain operating parameters to help determine root cause for the failures. To accomplish this, real time temperature data was obtained for selected points on the coupling profile during certain transients which presented a comparison to changing parameters. In this way, certain design criteria were more thoroughly analyzed for their applicability to the currently experienced loading of the couplings.
Thermosense XIX: An International Conference on Thermal Sensing and Imaging Diagnostic Applications
22 April 1997 | Orlando, FL, United States
Course Instructor
SC317: Infrared Thermography Applications in Power Generation and Distribution
This course provides attendees with a working knowledge of typical and advanced applications of infrared monitoring in the Power Generation and distribution industry. The course focuses on proven applications, and includes instruction in preparing effective and reliable reports and cost-benefit calculations to achieve and maintain management support for the program.
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