In this article, we will explore some of the ways they do just that. Among the measures vibration analysts use to help the environment include reducing secondary damage and improving the life of rotating machinery (which ensures that resources are not wasted); reducing machine failures that may lead to environmental damage; lowering vibration levels and improving balance and alignment to reduce energy consumption; monitoring pumps, turbines and other equipment to ensure they are running at peak efficiency; and monitoring wind turbines to ensure continued supply of renewable energy. Of course, if vibration analysts also perform oil analysis, motor circuit analysis and other condition-monitoring tasks, they can contribute even more environmental benefits.
Reducing Secondary Damage
When a bearing fails, additional damage can be done to the machine; shafts, seals, impellors and other components also may be damaged and therefore need to be replaced. While this results in a longer period of downtime (and potentially overtime labor) and a larger repair bill, it also results in waste. The energy and resources required to manufacture and transport those components have been wasted. The vibration analyst plays a key role in minimizing the secondary damage. Early and accurate diagnosis and the provision of clear, actionable information ensure that the replacement can be managed in the most cost-effective manner.
Normally when we discuss improvements to reliability, the focus is on reducing downtime (and overtime hours and parts inventory) and improving safety. But from an environmental point of view, improving reliability results in less waste because fewer parts are being replaced over the lifetime of the machine. Although your plant may have a recycling program, there is no doubt that having a bearing remain in service for 10 or more years is far better for the environment than using multiple bearings during the same period.
The vibration analyst is responsible for detecting the bearing fault and ensuring that the bearing does not fail catastrophically. But the most cost-effective and environmentally responsible activity that a vibration analyst can perform is to ensure that the bearing does not develop the fault in the first place. These activities include:
Making sure the machine is precision aligned and balanced.
Ensuring belt tension is set correctly and machines are not resonating.
Checking that machines are lubricated correctly.
Making sure that bearings are installed (and stored and transported) correctly.
Ensuring that the plant has an effective acceptance testing program.
As a separate, but definitely related issue, the vibration analyst should attempt to influence the design, engineering and purchasing process. For example, if new equipment is designed to be reliable and high efficiencmotors that are rated correctly for the application are purchased, then reliability will be improved and the environment will benefit.
In addition, the vibration analyst should play a key role in the root cause failure analysis process. When a problem develops, such as in a bearing, rotor, or any other component, the vibration analyst should be part of the team that determines why the fault developed and what can be done to ensure it does not happen again.
If the reliability of a machine is improved and the vibration analyst is utilizing all of the tools correctly, then machine failures should be reduced drastically. If a pump fails and toxic material is leaked into a stream, the environmental consequences are obvious. Pumps in the petrochemical, sewage/waste water, pulp/paper and other industries clearly represent a risk. Fires that start as a result of failure also impact the environment.
The Sayano-Shushenskaya hydroelectric power station accident1 in 2009 represents one of the more extreme examples. Increasing vibration levels were not acted upon and ensuing failures resulted in tragic loss of life and substantial environmental damage. The environmental impact was four-fold: massive amounts of water rushing down the river; 39 tons of transformer oil contaminating the river; destruction of 390 tons of cultivated trout in riverside fisheries; and the need to power smelters and other facilities with diesel generators due to the lack of power supply from the 6400 MW hydroelectric power station.
High Vibration Amplitude: Unbalance and Misalignment
There is some debate about this topic in certain forums,2 although I personally do not understand why. If a machine is properly balanced and aligned and is running with "low" vibration readings, it is reasonable to conclude that the bulk of energy consumed is being used for the intended purpose: pumping the fluid, compressing the air, moving air, etc. However, if the vibration amplitude is increased due to unbalance or misalignment, the motor has to do more work.
In the following case study, a belt-driven fan used in the production of breakfast cereal was determined to be out of balance. After balancing the machine, the current draw was reduced by 5 amps. The motor was a 75 HP US Motor operating at a nominal speed of 1800 RPM. If you know what you pay per kilowatt hour and the voltage of the motor, you can readily determine what those 5 amps are costing you, day-in and day-out.
When a machine is misaligned, the motor is fighting against the offset and angle between the shafts - the "bind" that occurs twice per revolution. While the forces related to unbalance and misalignment reduce the life of the machine, they also result in additional energy consumption. There are a few papers that discuss this issue with varying conclusions. 3-6
Vibration and Product Quality
In a number of industries, vibration relates to product quality. Reduced product quality can result in waste and, of course, waste is bad for the environment. Here are a few examples:
Corrugation or "barring" in rolls (or felt) on paper machines (and other similar processes) results in paper that is not a consistent thickness. Rejected paper may be recycled, but the energy consumed in creating the pulp and drying the paper is wasted. Vibration analysis can be used to detect the condition and determine the root cause.
When timber is cut into boards, any vibration on the saw blade results in a cut that is thicker than necessary - which results in waste. The same situation exists in other cutting operations, for example, cutting silicon wafers used in solar collectors.
In general, vibration in a production process can result in poor quality for a variety of reasons. In the printing, biosciences, semiconductor and aerospace industries and in applications where lasers and sensitive optics are involved, vibration must be kept to a minimum. Vibration analysts are involved in reducing vibration, both by taking care of unbalance, misalignment, resonance and other vibration sources, and by designing isolators.
Renewable Energy - Wind Turbine Monitoring
Wind turbines represent a major opportunity to generate energy using a free and clean source of energy. Wind turbines are amazing structures and the drive train (the main bearing, planetary gearbox and generator) are a feat of engineering. But they operate in tough environments; fluctuating load and temperature extremes in a housing (the nacelle) that is vibrating, flexing and resonating. Failure of the gearbox and other components results in very high costs that threaten the viability of wind projects; and when there is a failure, the wind turbine is no longer generating energy.
Vibration analysts will play a key role in ensuring the success of this industry. By detecting faults at an early stage, the wind turbine can continue to operate (possibly generating less energy) until the repair can be scheduled. Given that the majority of wind turbines are in remote locations or out at sea and will require a very expensive crane if there is major damage, the success of the condition monitoring program is vital.
Other Condition Monitoring Technologies
Vibration analysts are often skilled in other technologies that also can result in reduced energy consumption, reduced waste, or less pollution. Here are some examples:
Lube oil is an important resource and disposal of the oil can be hazardous to the environment. When it is replaced on a schedule based purely on days of operation, "perfectly good" lube oil may be wasted. Oil analysis tests can quickly determine the condition of the oil and whether its cleanliness and lubricating properties still meet the requirements.
Voltage unbalance results in current unbalance. Current unbalance results in heating and damage to windings. Heat represents energy loss and damaged windings can result in reduced life and even fires. There are a number of excellent articles and papers7 on the benefits of improving motor efficiency and the cost associated with reducing current draw.
Infrared thermography can detect a number of electrical problems that could cause or be a result of voltage or current unbalance or electric motor faults. An increase in temperature represents wasted energy and results in reduced life.
Performance monitoring can be used to determine if, for example, a pump is being operated at its best operating point (BOP). Incorrect operation of the pump can result in reduced life and inefficient operation - another waste of energy.
Using ultrasound, steam and compressed air leaks can be detected, thus reducing the energy consumed to provide the required amount of steam or air. It is also possible to determine if steam traps are operating correctly.
Whenever you meet a vibration analyst, take the opportunity to thank the person for the great job he or she is doing for your organization and the environment. Analyzing vibration can result in reduced energy consumption, improved product quality (and therefore reduced waste), improved process efficiency and improved reliability.
3. Jesse, Stephen, Hines, Wesley J., Kuropatwinski, James, Edmondson, Andrew and Carley, Thomas G. Motor Shaft Misalignment Versus Efficiency Analysis. Tennessee: The University of Tennessee College of Engineering Maintenance and Reliability Center.
4. Ludeca Inc. Evaluating Energy Consumption on Misaligned Machines. Maintenance Study, 1994.
Jason Tranter is the founder of Mobius Institute and author of iLearnVibration and other training materials and products. Jason has been involved in vibration analysis in the USA and his native Australia since 1984. Before starting Mobius Institute, Jason was involved in vibration consulting and the development of vibration monitoring systems. www.mobiusinstitute.com
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