Looking into the future of production technology3 steps to energy efficiency in pneumatic systems.
Pneumatic systems are considered to be inherently inefficient, so little is done to improve them. However, this article will show how these systems can be optimized to not only improve energy efficiency, but also enhance productivity and lengthen the life of the machine.
The good news is while there are many sources of inefficiencies in pneumatic systems, implementing these strategies can reduce energy consumption by as much as 35%.
Options for improving efficiency:
- Find and fix leaks
- Correct compressor operation
- Optimize component sizes
Find and fix leaks
Just because leaks are very common in pneumatics systems, it doesn’t mean they can’t be remedied. The U.S. Dept. of Energy statistics indicate the average manufacturing plant experiences compressed air leakage in the range of 30% to 35%.
Fortunately, many of these leaks can be fixed or even prevented. Of the many points between the compressor and the load where leaks occur, valves and seals are two main areas for improvement. Deteriorated seals should be the first area to examine. It’s also important to understand the nature of leaks to select the best valve for the job.
Certain spool valves with negative lap with metal seals have inherent internal leakage that is constant while air is supplied to the valve. Simply installing valves with soft seals can significantly lower leakage.
Nonetheless, it’s important to note that spool and metal sleeve valve air consumption doesn’t vary during operation. On the other hand, a soft seal produces hundreds of times more leakage than the lapped spool-and-sleeve valve during an open crossover when the valve shifts. Therefore, total air leakage can be optimized by selecting the right type of valve for the application.
Environmental conditions, such as temperature, moisture content. and lubrication, all contribute to the leakage rate of a seal. Pneumatic systems in areas with high contamination risk can benefit significantly from an investment in resilient seals like Viton, Teflon, or polyurethane.
Correct compressor operation
After fixing leaks, compressors are the next biggest area for improvement. The U.S. Dept. of Energy reported in a 2012 study that manufacturers spend over $5 billion each year on energy for compressed air systems. This shouldn’t be surprising since they form the backbone of the pneumatic system.
Manufacturers that optimize their compressed air supply systems have been able to reduce their compressed air energy consumption in the range of 20% to 35%.
Optimize component sizes
It’s important to take the time upfront 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 over sizing the cylinders more than necessary. Some over sizing 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.