PUMP CYLINDER-PISTON UNIT Russian patent published in 2001 - IPC

FIELD: mechanical engineering; pumps. SUBSTANCE: pump cylinder-piston unit has piston with core and rubber cup arranged in cylinder and second on rod. Core accommodates heat exchanger closed by distant bushing with ring outer bead. Channel to deliver liquid to heat exchanger is made in rod and in wall of distant bushing. Support side of cup is provided with increased hardness rubber ring. Modulus of elasticity of cup surface layer exceeds that of its core. Screw multistart grooves are made on outer surface of cup. Grooves begin behind front sealing edge. End gets into ring groove on support side of cup before increased hardness ring. Screw grooves communicate with heat exchanger, and ring groove, with rod space of cylinder. EFFECT: increased service life and reduced heat stress of unit. 4 cl, 2 dwg