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Electronic pumpcontrol system

  • US 5,190,442 A
  • Filed: 09/06/1991
  • Issued: 03/02/1993
  • Est. Priority Date: 09/06/1991
  • Status: Expired due to Fees
First Claim
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1. In a pumping system which includes a container for liquid, an inlet for the inflow of liquid entering the container, means for ascertaining the liquid level in said container and for generating a first signal corresponding to the current level, a plurality of pumps each having an inlet communicating with the interior of the container and an outlet communicating with a common conduit for liquid being pumped out of the container, and a pump controller for receiving said first signal and for starting and stopping individual pumps,the improvement comprising:

  • pressure sensing means in said conduit for sensing the backpressure against which pumps in operation are pumping and for generating a second signal corresponding to said sensed backpressure, the pump controller receiving said second signal,the provision, operatively connected to the pump controller, of an addressable memory for storing values corresponding to pumping rates vs. backpressure for each of said pumps, along with high and low backpressure values for each pump, andprocessor means operatively connected to the pump controller, the processor means being programmed such that;

    (a) on high backpressure, the pump controller avoids pumpstarts which will not result in a net increase in the total pumping rate;

    (b) on a decrease in backpressure, the pump controller allows more pumps to start when called for, and allows for the starting of more pumps than the minimum necessary, in order to decrease the duration of pumping;

    (c) the pump controller avoids a pumpstart under conditions which, given the stored high and low backpressure values for the respective pump, would result in the pump undergoing rapid on/off cycling;

    (d) the pump controller avoids the starting and stopping of pumps on pressure surges, by delaying any action for a given time period longer than the duration of a typical pressure surge.

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