Knowledge: how to evaluate compressed air leakage?

Compressed air is one of the most widely used power sources in the industrial field. Because it has many advantages, such as safety, pollution-free, good regulation performance and convenient transportation, it is more and more widely used in the field of modernization and automatic power. Compressed air is also an expensive energy source. Continuously reducing the overall operating cost of compressed air is an important topic for factory managers of every air compressor brand.

Compressed air leakage is almost a common energy waste in factories. The average leakage of compressed air accounts for 30% of the total compressed air, which means that tens of thousands of electricity bills are leaked every year. Some leaks are very obvious. They not only make a lot of noise, but also can be found by touch and vision. Some leaks are very hidden. In addition to small and hard to hear sounds, "hidden" leaks often occur in the environment with large background noise in the workplace. All the above leaks constitute the leakage source in the whole system.

Leakage usually occurs in the following parts:

1. Pipe joint and quick plug joint;

2. Pressure regulator (FRL);

3. Frequently open condensate drain valve;

4. Broken hose and broken pipe.

For a normal system, it is difficult to avoid leakage. According to the relevant investigation results of the U.S. Department of energy (DOE) and the author's long-term experience, leakage exists in every system, and nearly 60% of factories have not taken any measures for the leakage in the air system.

Of course, it is almost impossible for an air compressor brand to completely eliminate the leakage. What we can do is to control the leakage of compressed air within a reasonable range. This "reasonable" scope and the scale of the plant are closely related to the old and new:

For new systems (less than 1 year) or small plants, the leakage rate shall be controlled between 5% and 7%

For systems or medium-sized plants with 2 ~ 5 years, the leakage rate is between 7% and 10%

For systems or large plants older than 10 years, the leakage rate is between 10% and 12%

Leakage not only directly leads to the waste of energy, but also indirectly leads to the increased risk of plant shutdown. When the leakage intensifies, the pressure of the whole compressed air system will drop. If you want to maintain the pressure of the air system, you must start additional compressors, which will further increase the power cost of the whole plant. In some factories, there are a large number of intermittent discharge devices, such as electronic blowdown valves. These valves basically discharge condensate or other waste liquid at fixed time intervals. During the discharge time, when the waste liquid has been discharged, a large amount of compressed air will leave the compressed air system. At a certain time, there may be multiple discharge valves venting at the same time. At this time, the pressure of the whole system will suddenly drop, or even exceed the minimum pressure acceptable to the system, resulting in the shutdown of the whole system. This is a typical operation accident.