| 摘要 |
<p>PCT No. PCT/AU93/00289 Sec. 371 Date Feb. 3, 1995 Sec. 102(e) Date Feb. 3, 1995 PCT Filed Jun. 17, 1993 PCT Pub. No. WO93/25833 PCT Pub. Date Dec. 23, 1993Pump (1) includes a pneumatic valve assembly (98) having a chamber (105) which is supplied by compressed air via an inlet pipe. Included within chamber (105) is a valve (109) with a chamber (111) divided into two separate compartments (112,113) by a pliant diaphragm (114). Diaphragm (114) is biased toward compartment (112) by a spring (115) and supports a plunger (116) which extends from chamber (111) and includes a frusto conical end (117) for selectively engaging seat face (99) and preventing air flow between chambers (105,90). Two air bleed passageways (119,120) respectively extend from chamber (90) and compartment (113) to atmosphere for allowing a gradual return to atmospheric pressure therein when the supply of compressed air is discontinued. A further bleed passageway (121) extends through diaphragm (114) to ensure a gradual equalization of pressure in compartments (112,113) such that the diaphragm will return to its original biased position. An aperture (125) extends between compartment (112) and chamber (91) and is selectively closed by a switch mechanism (126) to prevent fluid flow therethrough. Switch mechanism (126) selectively opens valve assembly (98) in response to liquid filling sump (6) and raising float (42) to an operative position. This allows compressed air to pressurize sump (6) and evacuate fluid from sump (6) via outlet pipe (22).</p> |
