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Electronic controller for a water purifying unit

  • US 4,851,818 A
  • Filed: 04/01/1988
  • Issued: 07/25/1989
  • Est. Priority Date: 04/01/1988
  • Status: Expired due to Fees
First Claim
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1. An electronic controller for use in a water purifying unit of the type having a tap water inlet, a purified water outlet, reservoir, a filter interposed between the inlet and outlet through which the tap water passes for purification, a first conductivity probe in the tap water for sensing the conductivity of the tap water, and a second conductivity probe in the purified water for sensing the conductivity of the purified water, the electronic controller comprising:

  • electrical pulse means activated by a power signal coupled to the input of the first and second conductivity probes for applying electrical pulses thereto resulting in output signals from each conductivity probe that are indicative of the impurity concentration of the water in which it is immersed;

    amplifying means activated by a power signal coupled to said first and second conductivity probes for amplifying the output signals from each of said conductivity probes by a predetermined gain to provide output signals which are approximately equal when the filter is all right; and

    comparing means activated by a power signal for comparing the output signals from said amplifying means and for generating a signal indicative of a needed filter change when the output signals differ in a first direction and a signal indicative that the filter is ok when the output signals differ in a second direction; and

    power control means for periodically supplying a power signal to said electrical pulse means, said amplifying means and said comparing means.

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