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US 4,357,131 AGranted
Detector for controlling the operation of a suction pump
OwnerGilbert Guillemotinventor
Life of this patent
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OwnerGilbert Guillemotinventor
Estimating the term…
A suction pump has a suction pipe extending into a tank for receiving liquid. A detector, connected to a control circuit for the pump, is arranged to initiate operation of the pump when the liquid in the tank rises above a predetermined level. The detector comprises a hollow member of insulating material connected to the free end of the suction pipe. The member has a transverse dimension which is greater than that of the suction pipe whereby a shoulder is defined which connects the member to the pipe. Two or more electrodes are mounted on the member and the pump is operated when the liquid completes a circuit between the two electrodes. The electrodes are protected by the shoulder from liquid running backwardly within the suction pipe when the pump has stopped. In addition, a time delay means is included in the control circuit to delay restarting of the pump once it has stopped.
In apparatus for pumping liquid from a tank, the apparatus comprising a suction pump having a suction pipe extending into the tank and a control circuit for controlling the operation of the pump, a detector connected to the control circuit and arranged to control the operation of the pump in dependence upon the level of liquid within the tank, the detector comprising an elongate member of insulating material connected to the free end of the suction pipe and extending below an upper level for liquid in the tank, said member being spaced in the transverse direction outwardly of the suction pipe to thereby define a peripheral zone between the suction pipe and said member, and at least first and second spaced electrodes mounted on said member so as to extend inwardly of said member, at least the first electrode not extending beyond said peripheral zone.
Dependencies are inferred from the claim text.