| 摘要 |
<p>PURPOSE:To prevent the increase in the frequencies of starting and stopping operations of an automatic type pump by operating a valve by the displacement of a diaphragm and increasing the fluid resistance in correspondence to the intensity of the pressure. CONSTITUTION:At the time of starting the pump, when the pump is in a forced lift, a positive pressure at the upper part of a diaphragm 41 to give a force in the direction of closing a valve 27, and a fluid resistance between the valve 27 and a valve seat 25 is increased. Therefore, a negative pressure is introduced in the periphery of the valve 27 and in the suction pipe 11. Therefore it limits the increase in the lift quantity and prevents the periods of starting and stopping from being shortened, and therefore the frequencies of starting and stopping operations do not increase.</p> |
