Vacuum driven fluid pump for an aspiration/irrigation instrument

Abstract

A fluid pump 20 used in a lavage instrument 10 that is driven by vacuum pressure is disclosed. Fluid pump 20 includes a fluid housing 30 connected to an external fluid source and a pneumatic cylinder 50 connected to an external vacuum source. A diaphragm 40 is shiftably disposed within fluid housing 30 to define an inner fluid chamber 31. Pneumatic cylinder 50 includes a cylinder casing 60 and a reciprocating piston 70, which defines a vacuum chamber 61. Piston 70 includes a poppet valve 80 and is connected to diaphragm 40 by two push rods 68. Negative pressure within vacuum chamber 61 draws piston 70 forward and compresses a return spring 67. As piston 70 is drawn forward, piston 70 pushes diaphragm 40 forward to expel fluid from fluid chamber 31 through an outlet port 36. Piston 70 is drawn forward until poppet valve 80 is unseated by its engagement with a post 66 which extends longitudinally from casing end wall 44. Unseating poppet valve 80 equalizes the pressure within vacuum chamber 61 and allows return spring 67 to push piston 70 and diaphragm 40 rearward. Fluid is drawn into fluid chamber 31 through an inlet port 34 by the rearward movement of diaphragm 40. During the rearward stroke of piston 70, poppet valve 80 is reseated and vacuum pressure is reestablished within the vacuum chamber.

Dependencies are inferred from the claim text.