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Apparatus and method for dilution and mixing of liquid samples

  • US 4,946,795 A
  • Filed: 08/18/1989
  • Issued: 08/07/1990
  • Est. Priority Date: 08/27/1987
  • Status: Expired due to Term
First Claim
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1. An apparatus for automatically diluting a sample with a diluent, comprising:

  • housing means containingsample application site means for receiving a sample;

    measuring chamber means having a first volume;

    receiving chamber means having a second volume, wherein said second volume is greater than said first volume;

    diluent application site means for receiving a diluent;

    first flow means for delivering a sample from said sample application site means to said measuring chamber means by the sum of capillary and gravitational forces upon addition of sample to said sample application site means;

    second flow means for delivering diluent from said diluent application site means to said measuring chamber means by the sum of capillary and gravitational forces upon addition of diluent to said diluent application site means;

    third flow means for delivering sample and diluent from said measuring chamber means to said receiving chamber means by the sum of capillary and gravitational forces;

    a stop flow junction located in said third flow means and adapted to the surface tension characteristics of the sample so as to provide sufficient back pressure resulting from contact between said sample and wall means of said housing means to prevent sample from flowing through said stop flow junction when sample is present at said stop flow junction;

    whereby addition of diluent to said diluent application site means after sample is added to said application site means and initiation of flow at said stop flow junction cause sample in said measuring chamber means to be delivered by said capillary and gravitational forces to said receiving chamber means along with a portion of said diluent, whereby a fixed ratio of sample to diluent is present in said receiving chamber means.

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