GB936679A - Improvements in or relating to screw pumps - Google Patents

Abstract

936,679. Meshing screw pumps. PNEUMATIKUS ES HIDRAULIKUS GEPEK GYARA. April 22, 1960, No. 14255/60. Class 110 (2). In a reversible intermeshing screw pump for liquids the driving spindle 3 has a load relief piston 5, one annular face G 1 of which communicates with a first sump N 1 in the pump, while a second annular face G 2 bounds a load relief space R, connected by a duct C 1 in the stator to a second sump P 1 , and also through a clearance r, a a space B and a non- return valve S to the sump N 1 . In operation, when the flow is to the left in Fig. 1, the piston face G 1 compensates for the axial load on the spindle 3 and any liquid lost through a piston clearance h is returned to the sump P 1 through the duct C 1 . When the flow is reversed, the piston face G 2 compensates for the axial load by means of pressurized liquid from the sump P 1 , and any liquid passing through the clearance r is returned to the first sump through the valve S to relieve a seal V on the spindle 3 of pressure. In Fig. 3, the pump is incorporated in a liquid rectifier having non-return valves J, K, L, M such that the pump can be operated in either direction of rotation while maintaining a constant direction of flow from a suction port Sz to a pressure port Ny, openings N 2 , P 2 being connected to the sumps N 1 , P 1 respectively.