| 摘要 |
When regulating the capacity of a rotary screw compressor in a refrigeration and heating pump system and when varying the built-in volume therein, lift valves are used which operate instantaneously and are either open or closed. In order to ensure sufficient pressure on the lift valves to effect closing, the wall of the lift valves is shaped with two different diameters and a sharply defined step therebetween. Upon closing, the sharply defined step is influenced by a pressure which is lower than the pressure influencing the end surfaces of the lift valve. |
