CONTROLLABLE CHECK VALVE Russian patent published in 2008 - IPC F16K15/18 

FIELD: machine building pipeline valves and fittings.

SUBSTANCE: invention relates to hydraulic automatic control equipment designed to protect systems against inadmissible pressure rise. Proposed controllable check valve has body with inlet and outlet channels and multistep cylindrical inner bore and stop, spool with stepped outer surface and stepped inner space accommodating spring-loaded gate. Inlet and outlet channels are arranged with displacement in diametrically opposite direction relative to axis of multistep cylindrical bore. One of steps of multistep cylindrical bore is provided with conical seat forming variable-section made in form of three-step bore. Spring-loaded stepped bushing is fitted in one steps. Said bushing is provided with axial restriction hole. Hole communicates with valve control space. Other inner step of spool forms variable-section ring restriction hole with conical gate coaxially installed inside and spring-loaded relative to bushing. Gate provided with cylindrical shanks. One of shanks projects beyond end face surface of spool and engages with spring-loaded piston pusher arranged coaxially. Behind-the-piston space of piston has adjusting screw, and it is coupled with valve control space through restrictor. Steps of outer surface of spool are smoothly connected by concave belt. Spool is provided additionally with radial restriction hole. Said hole is located in zone of step forming ring restriction hole and it connects outlet channel with inner space of spool.

EFFECT: improved reliability of process, simplified design of value at provision of stepless change of flow at accompanying loads in main lines.

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