| 摘要 |
<p>A pneumatic pump (50) comprises two coaxial cylindrical pumping chambers (60, 62), each enclosing a piston (54, 56) connected to the other through a partition (58) by a tube (64), thereby forming a monolithic piston assembly that is driven axially by a common electrical actuator (68) providing reciprocating motion. The volume in the bottom chamber is selected as needed to provide the desired pressure in the left ventricle (34) of an artificial heart (30) driven by the pump (50). The diameter of the tube (64) connecting the pistons (54, 56) is selected such that the stroke volume of the top chamber (60) is reduced with respect to that of the bottom chamber (62) as needed to match the reduced pressure requirements of the right ventricle (32) of the artificial heart. Check valves (74, 76, 78, 80) are used in each chamber to ensure venting of excess pressure during the blood ejection phase and to limit the vacuum during the fill phase.</p> |
