Throttle for hydraulic mine roof support - has safety valve in form of movable plunger within piston set by variable spring

摘要

The reducing valve is for hydraulic machines and mechanical equipment, esp. hydraulic mining roof supports. A piston is acted upon on one side by the fluid pressure and on the other side by a spring assembly, whose spring pressure is variable. an integral safety valve is opened or closed by the piston movement. The safety valve (4) is in the form of a movable plunger (20) within the piston (3). There is a stop (6) between the piston (3) and spring assembly (5) and this can be fixed by a set screw (11). The piston has a bore (17), whose top end (18) is in the form of an inclined surface (16) which corresponds with the safety valve seat (13).