| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a positive-displacement pump, wherein even when the pressure on the fluid inlet side increases, a fluid is prevented from flowing from a fluid inlet to a fluid outlet via a pump chamber. <P>SOLUTION: In an active valve 4 disposed between the pump chamber 8 and the fluid inlet 6a, a valve element 43 is located on the upstream side from a valve seat 44 in the flow direction of a fluid. The valve element 43 moves between a closing position 43A in which the valve element is brought into contact with the valve seat 44 from the upstream side in the flow direction of the fluid and closes a lower end opening 423a, and an opening position 43B in which the valve element moves away to the upstream side in the flow direction from the closing position 43A and opens the lower end opening 423a. As a result, the force F6 caused by the fluid pressure of the fluid flowing from the fluid inlet 6a into the active valve 4 acts in the direction in which the valve element 43 is moved toward the closing position 43A. Accordingly, when the pressure on the fluid inlet 6a side increases, the valve element 43 is biased to the closing position 43A by the force F6 caused by the fluid pressure of the fluid. Consequently, an inflow-side flow path 9 is not opened. <P>COPYRIGHT: (C)2012,JPO&INPIT |
