| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress the occurrence of abnormal rise of pressure, abnormal reduction in pressure, and reverse flow in a flow passage in a forced opening and closing check valve used in a reciprocating pump. <P>SOLUTION: The valve elements 26 of forced opening and closing check valves 22 and 24 are driven by an actuator 36 including a stem 56 to openably control the flow passage. The stem 56 and the valve elements 26 are engaged with each other through a clearance d. Except when the stem 56 is at the end of the range of a play, the valve element 26 does not receive restriction by the actuator and its movement is allowed. Since the valve element 26 is brought into a state where its movement is allowed near a boundary between the discharge and suction strokes of the reciprocating pump, the valve element 26 can be moved according to the rise in pressure and a reduction in pressure, and the abnormal rise in pressure, abnormal reduction in pressure, and the reverse flow can be prevented from occurring. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
