The suction cavity includes a suction valve and a forcing valve.

A controlled or regulated pressure valve (24) is allocated to said positive displacement circulation pump (18) on the delivery side.

The outlet check valve is disposed within the piston.

The discharge reed valve contains an immobilized section, an intermediate section, and a valve section.

Each of the passages has at least one outlet check valve (5; 7).

The disclosed compressor is provided with a discharge chamber, a compression chamber, a partition, and a discharge reed valve.

A valve control mechanism is disposed in the housing and connected to the crankshaft, the inlet valve and the outlet valve.

An outlet valve (12) and a flush water valve (17) are attached to the water chamber (1).

A space is formed between the movable part of the spring reed and the opening/closing part of the discharge reed, and both are not adsorbed each other, thus preventing a delay in closing of the discharge reed.

Either the inlet or the outlet valve is a passive valve controlled by a pressure differential across the valve generated by the displacement pump, and the other of the inlet and the outlet valve is an active valve controllable by an actuator.

Preferably, said component has a radial pressure valve (81) relative to the centre axis and a valve seat body (70).

Contact zones (a, b, c) are available between the suction valve (6, 26, 26') and the feed valve (17, 21, 23).

A reciprocating pump comprises a cylinder, an inlet check valve, a piston, an outlet check valve and a purge circuit.

The purge circuit extends across the inlet check valve and the outlet check valve to fluidly couple the first end and the second end.

  Further provided is a gasket which withstands the cyclic stress of a discharge valve.