Artificial heart pumping system powered by a modified stirling cycle engine-compressor having a freely reciprocable displacer piston

Claim 1

In an artificial heart system including at least one fluid actuated artificial ventricle and a fluid-pumping means connected to said ventricle, wherein said pumping means is provided with a pressure input and a pumping fluid output connected to said ventricle, a fluid pressure-operated control system for reciprocating fluid through said pumping means to actuate the ventricle in simulating systole and diastole, and a source of high-pressure working gas for operating the control system; the improvement wherein the source of high-pressure working gas comprises a Stirling cycle engine, said Stirling cycle engine comprising: a cylinder having opposite end portions respectively disposed in hot and cold zones, a source of thermal energy operably associated with the end portion of said cylinder disposed in the hot zone for heating the working gas in the hot zone, a regenerator having opposite ends respectively extending into the opposite end portions of said cylinder within the hot and cold zones, a piston mounted for reciprocation in said cylinder to transfer the working gas between said zones through said regenerator, respective high and low pressure reservoirs of working gas maintained at said high and low pressures, means separately connecting each of said high and low pressure reservoirs to said cylinder at the end portion thereof disposed in the cold zone, a first valve means in said means connecting said high-pressure reservoir to said cylinder, a second valve means in said means connecting said low-pressure reservoir to said cylinder, said piston being positioned in the end portion of said cylinder disposed in the hot zone at the beginning of its stroke and said first and second valve means being closed to prevent communication between the end portion of said cylinder disposed in the cold zone and said high and low pressure reservoirs respectively, said first valve means opening in response to the movement of said piston toward the end portion of said cylinder disposed in the cold zone increasing the pressure of the working gas in said cylinder to a magnitude at least equal to the pressure of the working gas in the high-pressure reservoir for admitting working gas into the high-pressure reservoir from said cylinder until the end of the piston stroke, said piston in its return stroke moving toward the end portion of said cylinder disposed in the hot zone so as to decrease the pressure of the working gas in said cylinder closing said first valve means, and said second valve means opening in response to the continued movement of said piston in its return stroke decreasing the pressure of the working gas in said cylinder to a magnitude no greater than the pressure of the working gas in the lowpressure reservoir for drawing working gas from said lowpressure reservoir into said cylinder, whereby the working gas is pumped from said low-pressure reservoir to said high-pressure reservoir which serves as the source of high-pressure working gas; means communicatively connecting the high-pressure reservoir to said control system for admitting high-pressure working gas thereinto to operate said control system, and means communicatively connecting said control system to the lowpressure reservoir for discharging working gas from said control system to the low-pressure reservoir for subsequent recycling through said Stirling cycle engine.