| 摘要 |
A pumping system protection device which continuously monitors the rate of flow from a pump, which provide pressurized liquid from a pump to a tank, through a check valve, such as can be used in a water well, for example, to provide water to a pressurized receiving tank. An orifice of selected small size is provided in the flow line means to the check valve and receiving tank. The purpose of this orifice is to bleed the pressure in the flow line whenever the pump stops delivering liquid. The pressure in the flow line at the point of the orifice is monitored by a pressure sensitive switch, which closes a contact when the pressure is below a selected small value. The contact controls power to the pump motor. If there is no liquid flow the contacts open, and power to the pump is cut off. If when the power switch is closed and liquid flows from the pump, the pressure sensitive switch will open its contact and leave the power switch in the closed position. When the flow stops and the pressure drops at the orifice, the pressure sensitive switch closes, which opens the power switch.
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