PILOT-CONTROLLED CHECK VALVE Russian patent published in 1999 - IPC

FIELD: mechanical engineering; lifting mechanism and processing equipment. SUBSTANCE: pilot-controlled check valve has housing accommodating shutoff valve, controlled piston with rod and partition enclosing the rod and forming, together with piston and rod, a rod space. Shutoff valve and housing form above-valve space communicating with outlet channel, and undervalve space. Bore is made in piston with rod past piston side to install spring-loaded plunger for limited displacement. Spring-loaded plunger has longitudinal hole and forms chamber in rod from side opposite to piston which is placed in communication with undervalve space through holes made in rod. Bore at piston side is stopped by plug. Other chamber is formed between plunger and plug. This chamber communicates with rod space through corresponding holes made in rod. Supply channel communicates with this rod space. EFFECT: reduced time taken for lowering loads of different weight, increased capacity of equipment, reduced mass-and-dimensional parameters of hydraulic system. 4 cl, 1 dwg