BYPASS VALVE Russian patent published in 1998 - IPC

FIELD: hydraulic devices for control of flow rate and pressure of working fluid; hydraulic systems of tractors and other machines for relief mode of hydraulic system. SUBSTANCE: bypass valve has two shut-off members. Outer member is made in form of differential spring-loaded taper valve with stepped cylindrical bore for reduction of pressure losses at idle bypass of working fluid. Inner shut-off member is made in form of spool valve received by bore of outer taper shut-off member; it closes its radial holes and has bead at the end supported by inner bearing surface of outer member and used as support for spring of spool valve. Spool valve is used for bypass of excessive working fluid in control of flow rate, thus ensuring higher pressure differential on throttle valve as compared with outer shut-off member. EFFECT: reliable protection against abnormal rise of pressure; proper control of flow rate through maintenance of constant pressure differential on control throttle valve. 5 cl, 3 dwg