| 摘要 |
<p>A pneumatic pump of the type having a pair of pump chambers (14, 16) each divided by a diaphragm assembly (32) coupled by a main shaft including a housing having a central valve chamber (50). The valve chamber is provided with a pair of internal walls between which a valve body (54) reciprocates. The valve body alternatively connects passageways from the pump chambers to the pump exterior, while pressurized gas supplied to the valve chamber simultaneously pressurizes the other pump chamber. The valve body is mechanically coupled to the diaphragm shaft (30), whereby the pump chambers are pressurized and evacuated on synchronism with diaphragm operation. The valve body is accessible through an aperture in the housing, allowing the body to be replaced without pump disassembly. An integral counter (122), mounted in the pump housing, is also coupled to the diaphragm shaft, and provides a count of the number of shaft reciprocations performed.</p> |
