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Ambulatory infusion pump

  • US 4,900,305 A
  • Filed: 06/27/1988
  • Issued: 02/13/1990
  • Est. Priority Date: 06/27/1988
  • Status: Expired due to Fees
First Claim
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1. A pulsed liquid injection device comprising:

  • liquid storage container for storing liquid under a pressure greater than that required for making an injection;

    a liquid metering chamber, having a predetermined capacity, for storing liquid under a pressure which is greater than that for making an injection but lower than the pressure in said first storage container;

    liquid dispensing means;

    a first liquid flow path between said storage container and said metering chamber;

    a second liquid flow path between said metering chamber and said liquid dispensing means;

    first valve means in said first liquid flow path movable between a first operating position in which said first liquid flow path is blocked and a second operating position which said first liquid flow path is open;

    second valve means in said second liquid flow path movable between a first operating position in which said second liquid flow path is blocked and a second operating position in which said second liquid flow path is open;

    timing means arranged, repeatedly at predetermined intervals, to (a) open said first valve means for just sufficient time to permit said liquid to flow into and fill said metering chamber and then return said first valve means to its first operating position, and subsequentially (b) open said second valve means for at least sufficient time to permit a predetermined volume of said liquid in said metering chamber to flow to said liquid dispensing means and then return said second valve means to its first operating position; and

    means intermediate said first and second valve means arranged to block said second liquid flow path in the event that liquid in excess of said predetermined capacity of said metering chamber is delivered thereto.

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