| 摘要 |
PCT No. PCT/SE91/00410 Sec. 371 Date Dec. 7, 1992 Sec. 102(e) Date Dec. 7, 1992 PCT Filed Jun. 7, 1991 PCT Pub. No. WO91/19098 PCT Pub. Date Dec. 12, 1991.A positive displacement pump, particularly a liquid metering or batching pump, includes a fluid inlet, a pump chamber of variable volume, an outlet through which fluid leaves the pump chamber, a driven injection member for repetitive displacement of fluid from the pump chamber, and a valve which functions to open and close a flow passage connecting the inlet with the pump chamber. The flow passage is formed by a gap which extends around at least the major part of the circumference of the pump chamber and which can be open to a height which varies from a smallest value at the ends of the gap to a largest value at a location between the circumferential ends of the gap. The valve includes a valve member which extends along the flow passage and which is pivotally mounted on a pivot adjacent the circumferential ends of the passage. |
