Bellows Pump

Abstract

A bellows pump including in its pump case ( 5 ) a pair of plastic bellows ( 6 ) that expand and contract to alternatingly execute an output stroke that sends fluid out of pump chambers ( 7 ) defined by the bellows and a suction stroke that supplies fluid to the pump chambers. Metal actuation plates ( 10 ) are provided in the pump case so as to be movable in the axial direction, and these actuation plates are fixedly connected to the bottom walls ( 6 a ) of the bellows in peripheral portions thereof so that the opposed end faces ( 10 c, 6 g ) of the actuation plates and fluid-contact portions ( 6 f ), which are at the center of the bottom walls of the bellows and come into contact with fluid in the pump chambers, are set in a close contact to each other. The close-contact portions are sealed by O-rings ( 15 ).

1 . A bellows pump adapted to cause a plastic bottom-closed cylindrical bellows with aperture portions thereof connected to a pump case to expand and contract in an axial direction thereof, thereby alternating between an output stroke in which fluid is sent from a pump chamber defined by the bellows to an output passage through an output check valve and a suction stroke in which fluid is supplied from a suction passage to the pump chamber through a suction check valve, wherein:
 metal actuation plates are provided in the pump case so as to be movable in an axial direction thereof,   the actuation plates and bottom walls of the bellows are fixedly connected in peripheral portions thereof,   opposed end faces of the actuation plates and the fluid-contact portions are set in a close contact with each other, the fluid-contact portions being central areas of the bottom walls of the bellows and coming into contact with fluid in the pump chamber, and   said close-contact portions are sealed with annular sealing members.   
     
     
         2 . A bellows pump adapted to cause a plastic bottom-closed cylindrical bellows with aperture portions thereof connected to a pump case to expand and contract in an axial direction thereof, thereby alternating between an output stroke in which fluid is sent from a pump chamber defined by the bellows to an output passage through an output check valve and a suction stroke in which fluid is supplied from a suction passage to the pump chamber through a suction check valve, wherein:
 metal actuation plates are provided in the pump case so as to be movable in an axial direction thereof,   the actuation plates and bottom walls of the bellows are fixedly connected in peripheral portions thereof,   sealed spaces are provided between opposed end faces of the actuation plates and central areas of the bottom walls of the bellows, said spaces being sealed by annular sealing members, and   said sealed spaces are filled with incompressible fluid.   
     
     
         3 . The bellows pump according to  claim 1 , wherein
 the annular sealing members O-rings, and   said O-rings are held in engagement with O-ring grooves formed in either one of the bottom walls of the bellows and the actuation plates.   
     
     
         4 . The bellows pump according to  claim 2 , wherein
 the annular sealing members O-rings, and   said O-rings are held in engagement with O-ring grooves formed in either one of the bottom walls of the bellows and the actuation plates.