Research on Sealing Performance in High Pressure Oil-Free Miniature Air Compressor

High pressure oil-free miniature air compressor has an irreplaceable role in some high demand areas such as cooling, scuba diving and pneumatic catapult due to its remarkable advantages such as compacted size, lightened weight and clean output gas. As the important sealing component in the high pressure oil-free miniature air compressor, piston rings hold the properties such as tiny diameter (less than 10mm), high sealing pressure (up to 410 bar) and high surrounding temperature (up to 500K), which make them distinctive from conventional piston rings. A mathematical model was established to simulate the pressure distribution of the compressor chamber, as well as the gap between the sealing rings. Sensitive parameters were considered to investigate their effects on the sealing performance such as the number and the cut size of the piston rings, the suction and discharge pressure and the rotary speed. The mathematical model was verified by comparing to published experimental research work. These work help to reveal the severe non-uniformity of the pressure distribution of different chambers, which were suggested be the primary cause of the premature failure of the sealing rings, thus improving the sealing performance and the service life of the air compressor.