reciprocating compressor, capacity control, pneumatic actuation
The forced actuation of usually self-acting valves inside reciprocating compressors offers the possibility of a step-less capacity control and therewith the opportunity of energy savings. Differently from nowadays typically used electromagnetic actuated grippers for forced opening of the suction valve, the present paper deals with the pneumatically forced opening of the discharge valve. Pressure, which is provided by the compressor itself, is directly applied to the valves sealing elements to apply the opening force. Only few external energy and effort is necessary. The working principle and the numerical observation on the system was presented in former papers. The actual paper deals with the verification of the simulation results presented in a previous publication. For that purpose experimental testing was applied to the valve system components and the whole assembly. Component testing was necessary since only few information were available on some valve parts, however for example their temporal characteristics were crucial for the in-compressor-tests. The integral testing was performed by means of a test compressor. The instrumentation was chosen properly, being able to evaluate valve and overall compressor performance at different operation points. Beside pressures in cylinder, suction and discharge chamber, also the pressure supply for the valve control and the valve lift itself were monitored. Thus it was possible to compare the fundamental characteristics of the valve system to the results received by the simulation.