Apparatus and method for dilution and mixing of liquid samples
First Claim
1. An apparatus for automatically diluting an aqueous sample with an aqueous 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 sit 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; and
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 at said stop flow means to prevent sample from flowing through said stop flow junction in absence of diluent but allowing flow through said stop flow junction when diluent is present in said apparatus along with said sample,whereby addition of diluent to said diluent application site means after sample is added to said sample application site means causes hydrostatic pressure at said stop flow junction to exceed said backpressure, whereby said diluent expels sample from said measuring chamber means and causes a fixed ratio of sample to diluent to be delivered to said receiving chamber means.
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Accused Products
Abstract
An apparatus for diluting a sample with a diluent, comprising a fixed volume measuring chamber, a fixed volume receiving chamber and fluid receiving relationship to the measuring chamber, a gas vent in the receiving chamber, a stop flow junction between the measuring chamber and the receiving chamber, a sample application site in fluid donating relationship to the measuring chamber, wherein the vertical height difference between the sample application site and the stop flow junction is insufficient to provide a hydrostatic pressure capable of overcoming backpressure at the stop flow junction when sample is applied to the sample application site, and the diluent application site and fluid donating relationship to the measuring chamber. Sample and diluent are added sequentially to the apparatus of the invention without requiring any intervening operations. Various means are provided for restarting flow, which causes diluent to wash the sample into the receiving chamber, where the two can be mixed.
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Citations
27 Claims
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1. An apparatus for automatically diluting an aqueous sample with an aqueous diluent, comprising:
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housing means containing sample 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 sit 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; and 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 at said stop flow means to prevent sample from flowing through said stop flow junction in absence of diluent but allowing flow through said stop flow junction when diluent is present in said apparatus along with said sample, whereby addition of diluent to said diluent application site means after sample is added to said sample application site means causes hydrostatic pressure at said stop flow junction to exceed said backpressure, whereby said diluent expels sample from said measuring chamber means and causes a fixed ratio of sample to diluent to be delivered to said receiving chamber means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16)
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17. A method for diluting an aqueous sample with an aqueous diluent, comprising:
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adding an unmeasured volume of said sample to sample application site means of a device in which said sample flows by the sum of capillary and gravitational forces to measuring chamber means having a first volume, said measuring chamber means being terminated by a stop flow junction which stops sample flow as a result of backpressure resulting from interaction of said sample with wall means of said device at said stop flow junction; and
thenadding said diluent to diluent application site means of said device, wherein said diluent flows by the sum of capillary and gravitational forces to said measuring chamber means and displaces sample into receiving chamber means having a second volume larger than said first volume when hydrostatic pressure resulting from the presence of diluent in said device exceeds said backpressure, whereby a fixed ratio sample and diluent fills said receiving chamber means. - View Dependent Claims (14, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification