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Submersible sump pump

  • US 4,396,353 A
  • Filed: 04/13/1981
  • Issued: 08/02/1983
  • Est. Priority Date: 04/13/1981
  • Status: Expired due to Fees
First Claim
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1. In a submersible sump pump having a motor which drives pumping means mounted in a pumping chamber forming part of the pump housing, the pumping chamber having inlet means through which liquid in the sump surrounding the pump may enter the low pressure zone of the pumping chamber and outlet means through which pumped liquid may leave the high pressure zone of the pumping chamber and pump housing, motor control means for causing the pump to commence operation whenever the liquid level surrounding the pump rises to a predetermined pump-activating level and for causing the pump to thereafter continue operation until the liquid level has fallen to a predetermined pump-deactivating level below said pump-activating level, the improved means for detecting the surrounding liquid level which comprises:

  • pumping chamber inlet means including a sensing chamber comprising first and second portions, said first sensing chamber portion having a sensing chamber inlet located at the pump-deactivating level and communicating with the surrounding sump, said first sensing chamber portion rising from said inlet to an overflow point located at the pump-activating level, said second sensing chamber portion communicating with the upper portion of said first sensing chamber portion above said overflow point whereby liquid rising in said first sensing chamber portion overflows into said second sensing chamber portion only after it rises above said overflow point, said second sensing chamber portion having an outlet into the low pressure zone of the pumping chamber;

    the pump, once activated, being capable of causing liquid to continue to flow through said first and second portions of said sensing chamber to the low pressure zone of the pumping chamber as a result of a siphon action which pulls liquid over said overflow point until the siphon is broken when the level of the surrounding liquid falls below said sensing chamber inlet;

    a liquid level sensing device located in said sensing chamber and capable of sensing the presence or absence of liquid at a predetermined point within said sensing chamber, which predetermined point contains liquid only when a rising liquid level has overflowed said overflow point and thereafter until said siphon action is broken;

    said sensing device being operatively connected to the motor control means to activate the motor and pump only when said sensing device senses that liquid is present at said predetermined point.

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