Because pneumatic systems are prevalent throughout manufacturing facilities and account for a large share of a plant's power costs, it is extremely important that they run efficiently. Unfortunately, many users have the mind-set that pneumatic systems are inherently inefficient, therefore overlooking opportunities for energy savings. And by optimizing these systems, many companies can reduce their compressed-air energy consumption by anywhere from 20 to 35%.
Leaks are common and expensive in pneumatics systems. Statistics from the U.S. Department of Energy show the average manufacturing plant loses 30 to 35% of its compressed air due to leakage. The good news is many leaks can be prevented or repaired.
After fixing leaks, compressors are the next biggest area for improvement. Manufacturers that optimize their compressed air supply systems have seen significant reductions in their energy consumption. The Dept. of Energy offers guidelines for determining the cost of compressed air in a plant, as well as tips on how to reduce compressor energy usage.
Use the shortest tubing/plumbing lengths possible to reduce energy consumption as well as cycle times. Typically, tubing between control valves and cylinders should be less than 10-ft long. Longer lengths require more pressure so that force, speed, and positioning capabilities aren't compromised.
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Another way to conserve energy is by supplying the correct pressure for an actuator's return stroke. Most applications only move a load in one direction. However, many machines inefficiently use the same pressure for both the working and return strokes. Reducing pressure for the retract stroke can conserve compressed air (energy) especially in high duty-cycle applications, and may also minimize wear and tear on pneumatic and related components. Another way to optimize efficiency of the return stoke is through the use of gravity or spring-return cylinders.
It's important to take the time up-front to correctly size the pneumatic system's components because each component's size affects other parts of the system. Buying smaller control valves may save money on the purchase price, but they will be more expensive over time. Smaller control valves will require the air compressor to work harder simply to get the proper pressure to the actuators, creating a long-term demand for more energy.
Another common problem comes from oversizing the cylinders more than necessary. Some oversizing is necessary to compensate for pressure fluctuations and air losses; however, components that are far too large account for one of the biggest energy losses in a pneumatics system.
Self explanatory, but often overlooked. Consider automating the process where possible: use solenoid operated dump valves to remove air from idle machinery or parts of the plant - under PLC control, based on time of day or other production criteria.