Dynamic characteristics of suction valves for reciprocating compressor with stepless capacity control system

Abstract

The dynamic characteristics of suction valves for reciprocating compressor with a stepless capacity control system are studied in this article. The self-acting valve model that is applicable for stepless capacity control condition is derived. For the suction valve movement controlled by actuator, a simulation of the hydraulic and mechanical system is conducted. An experimental platform is setup, which is used to test the valve dynamic when it is controlled by actuator. The results from the mathematical model show that the valve impact speeds are influenced by the valve lift, Mach number of the flow in the valve clearance and the initial crank rotation angle of the valve closing process. The simulation results agree well with experimental results. The simulated maximum speed is about 0.53 m/s, and the maximum speed tested by experiment is about 0.58 m/s, both of which are much lower than the speed of the automatic valve (3 m/s). In addition, simulation results show that the maximum speed is at constant when the hydraulic piston stroke increases, which is much different from the automatic valve. It becomes apparent from the aforementioned results that with stepless capacity control system the dynamic characteristics of the suction valve are changed. The valve can be limited at a low speed, and the valve impact speeds to seat and stopper decrease significantly, which would be helpful for extending the life of the valve plate.