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IV Pump with back pressure control

  • US 4,322,201 A
  • Filed: 09/21/1979
  • Issued: 03/30/1982
  • Est. Priority Date: 03/09/1979
  • Status: Expired due to Term
First Claim
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1. A volumetric infusion pump for pumping fluid from a reservoir to a patient, the volumetric infusion pump comprising:

  • a pump inlet for connection to the reservoir;

    a pump outlet for connection to the patient;

    rolling diaphragm pumping chamber means connected between the pump inlet and the pump outlet;

    pressure sensing means connected between the rolling diaphragm pumping chamber means and the pump outlet for sensing pressure;

    wherein the pressure sensing means comprises;

    a cylinder;

    a piston movable in the cylinder;

    flexible diaphragm means between the cylinder and the piston defining a pressure sensing chamber; and

    spring bias means for applying a force urging the piston in a direction which reduces the volume of the pressure sensing chamber, and wherein pressure in the pressure sensing chamber applies a force urging the piston in a direction which increases the volume of the pressure sensing chamber; and

    valve means between the pressure sensing means and the pump outlet for controlling fluid pressure in the rolling diaphragm pumping chamber means wherein the valve means restricts a flow passage between the pumping chamber means and the pump outlet to increase pressure in the rolling diaphragm pumping chamber means if the pressure sensed by the pressure sensing means is less than a predetermined level, and wherein the valve means does not restrict the flow passage if the pressure sensed is greater than the predetermined level.

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