| 摘要 |
<p>PURPOSE:To close a valve at a gentle speed and prevent a water hammer, by holding a position of valve opening with liquid itself, releasing the holding liquid to a passage at automatically closing of the valve and forming said passage to a small dismeter. CONSTITUTION:The numeral 67 is a cylindrical valve unit of H-shaped longitudinal section, liquid-tightly slidably fitted between a cup-shaped unit 37 and valve seat 57 secured to a housing, and can be lifted by a control rod 74 against a spring 80. Now the valve unit 67 is manually lifted, if water is supplied from a supply port 17, the water partially passes from a suction part 83 through a passage 81, and is filled in a valve unit lower chamber 73 to hold the valve unit to a lifted state. If a level of water comes to a level L1, water from a suction part 84 also passes a passage 82 to enter a valve unit upper chamber 72, and water pressures in the upper and lower chambers are balanced, then the valve unit 67 is depressed only by action of resilient force of the spring 80, here the water from the lower chmber 73 is discharged only through the passage 81 of small diameter, in this way, the valve unit can be returned at a gentle speed.</p> |
