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Infusion control apparatus

  • US 4,509,943 A
  • Filed: 08/03/1982
  • Issued: 04/09/1985
  • Est. Priority Date: 08/10/1981
  • Status: Expired due to Term
First Claim
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1. An apparatus for controlling drop-wise infusion of an infusion liquid through a flow passage, wherein a drop chamber is provided upstream of the flow passage, the apparatus comprising:

  • input means arranged to be operatively associated with the drop chamber for forming an input signal on the basis of a change in a quantity of light received by said input means after the light is passed through falling drops of the infusion liquid in the drop chamber, wherein an absence of said input signal indicates either one of an exhaustion in supply of the infusion liquid or a continuous stream of liquid falling in the drop chamber;

    flow adjusting means arranged to interact with the flow passage for adjusting the flow of infusion liquid in the flow passage;

    drop interval control means coupled to said input means adapted to evaluate the interval between successive falling drops of infusion liquid in the drop chamber in response to said input signal, for producing a control signal operative to establish a drop interval adjustment mode wherein said flow adjusting means adjusts the flow of infusion liquid to bring said interval into correspondence with a set value;

    cut-off means coupled to said drop interval control means and to said flow adjusting means for establishing a liquid cut-off mode wherein the flow of infusion liquid through the flow passage is closed off by said flow adjusting means upon detecting the absence of said input signal over a predetermined period of time, said cut-off means providing a corresponding output to said flow adjusting means; and

    drop count means coupled to said input means and to said cut-off means for detecting said input signal after initiation of said cut-off mode, wherein said drop count means produces a signal to restore said flow adjusting means to operate in said drop interval adjustment mode when said input signal indicates a set number of drops have fallen in the drop chamber after the flow of infusion liquid through the flow passage is closed off by said flow adjusting means in said cut-off mode, so that said flow adjusting means remains in said cut-off mode if the supply of infusion liquid is exhausted, and is restored to said drop interval adjustment mode if said set number of drops fall in the drop chamber after the flow passage is closed off in the absence of said input signal over said predetermined period of time.

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