Abstract: A pneumatic pump adapted primarily as a left ventricular heart assist device includes a flexible bladder with a rigid housing. A pneumatic driver applies rhymical pulses between the bladder and the housing to repetitively collapse the bladder and establish a pumping action through the bladder, in conjunction with check valves in the inlet and outlet to the bladder. Between the driver and the pump there is provided a pneumatic pulse limiter which includes a flexible diaphragm isolating the driver from the pump. Pulses from the driver are transmitted to the pump only through the flexible diaphragm and the diaphragm is constrained to move only within established limits. Regardless of the magnitude of the pulse from the driver, the maximum pulse applied to the pump cannot exceed that corresponding to the maximum displacement of the diaphragm.Between successive pulses, the portion of the system between the driver and the flexible diaphragm is depressurized.

Abstract: A pneumatic pump adapted primarily as a left ventricular heart assist device includes a flexible bladder with a rigid housing. A pneumatic driver applies rhythmical pulses between the bladder and the housing to repetitively collapse the bladder and establish a pumping action through the bladder, in conjunction with check valves in the inlet and outlet to the bladder. Between the driver and the pump there is provided a pneumatic pulse limiter which includes a flexible diaphragm isolating the driver from the pump. Pulses from the driver are transmitted to the pump only through the flexible diaphragm and the diaphragm is constrained to move only within established limits. Regardless of the magnitude of the pulse from the driver, the maximum pulse applied to the pump cannot exceed that corresponding to the maximum displacement of the diaphragm.Between successive pulses, the portion of the system between the driver and the flexible diaphragm is depressurized.

Abstract: Disclosed is a pumping system using a pneumatically powered, submerged pump for lifting high viscosity oil from a well. The pump includes a flexible, bag-shaped expansible member or "bladder" mounted within a surrounding housing. Pressurized gas is supplied from the well surface to the bladder through a supply line. An inlet check valve permits oil in the formation to flow into the housing when the bladder is collapsed. When the bladder is expanded or displaced by the gas, the oil in the housing is displaced through an outlet check valve into a flow line which extends to the well surface. A submerged control valve channels gas into the bladder to control the bladder expansion. The control valve also functions to permit the gas in the bladder to flow into a vent tube to control bladder deflation.In a modified form of the invention, oil flowing into the housing expands the bladder and gas supplied to the housing collapses the bladder.

Abstract: A pneumatically controlled liquid transfer system for delivering a liquid from a source to a delivery location, said liquid source being provided with a pneumatic cylinder for driving the liquid from said source, a pneumatically operated pinch valve of the make-before-break type and flexible conduit paths leading through the valve to the delivery location. The make-before-break pinch valve comprises a valve shell having two pistons movable laterally therein. The shell has a window. One piston has a yoke, each arm thereof having a passageway, one aligned with the other. A stop extends between the arms of the yoke. One of the flexible conduits is arranged through the window between the first piston and the yoke and the other flexible conduit is arranged also through the window but within the aligned passageways and between the piston and post. The second piston is spring biased to bear against the second conduit to place same in a normally closed condition. The first conduit is normally open.