GB1170827A - Fluid Pump - Google Patents

Abstract

1,170, 827. Flexible chamber pumps. INTERNATIONAL BUSINESS MACHINES CORP. Oct.2, 1967 [Nov.7, 1966], No.44719/67. Heading F1A. A hydraulically-actuated flexible chamber pump, e.g. for blood, comprises a collapsible tubular member 10 mounted in a chamber of actuating liquid cyclically pressurized by a crank-driven piston 22, and connected to an inlet 14 and a check valve-controlled outlet 16, the resistance of the walls of member 10 to collapsing under pressure increasing from the inlet end to the outlet end. When the actuating liquid pressure is increased by piston 22, the inlet end of member 10 collapses first and closes off the inlet. The rest of the member then progressively collapses towards the outlet to discharge its contents via check valve 18. When the actuating liquid pressure is reduced by piston 22, valve 18 closes, and member 10 remains collapsed until the pressure is low enough for the inlet end to open to admit a fresh charge, thereby producing a self-cleaning action. The increasing collapsing resistance may be obtained by tapering the exterior, as shown, or interior of member 10. Alternatively, member 10 may be formed by concentric tubes of different lengths cemented or moulded together, Fig. 2 (not shown), or by an elastic member the modulus of elasticity of which increases from its inlet end to its outlet end, Fig. 3 (not shown). The variation of the modulus of elasticity may be obtained by immersing a member of uniform elasticity in a solvent which will leach out the plasticizer, and then withdrawing the member so that it is subjected to different amounts of leaching along its length. In the embodiment of Figs. 4 to 6 (not shown), the tubular member is subjected to initial deformation by rigid tapered saddles, the degree of deformation decreasing from the inlet end to the outlet end, to provide the required variation of resistance to collapsing. A number of pumping members of different capacities may be mounted in a common actuating chamber.