Oil stop valve for helical screw compressor - has bore with orifices through valve piston to achieve rapid closure

摘要

The compressor has oil delivered to it from the sump of the oil separator in the discharge through a stop valve which is operated by the discharge pressure. The valve has an oil inlet (17) and outlet (14) with a valve seat (13) between them on which a differential pressure piston (4) closes. Compressor discharge pressure is admitted (16) to one side of the piston. The piston has an axial bore (5) through it with radial throttling orifices (11) from the bore to the space (6) above the sump side. These allow discharge pressure to build up gradually on the sump side to bring about rapid closure when the compressor stops.