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Mouth alcohol tester

  • US 8,756,974 B2
  • Filed: 03/22/2012
  • Issued: 06/24/2014
  • Est. Priority Date: 07/05/2007
  • Status: Active Grant
First Claim
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1. A breath alcohol tester, comprising:

  • a breath manifold designed to accept breath from a human subject, said breath including an early breath followed by a later breath;

    a flow restriction, wherein an action of said breath in said breath manifold against said flow restriction creates a positive pressure in said breath manifold;

    a fuel cell; and

    a sampling system, the sampling system comprising an electrochemical volume-displacement device;

    wherein said manifold is configured to use said positive pressure in said manifold to force at least a portion of said early breath into said fuel cell via backpressure without said sampling system sampling said early breath;

    wherein the amount of alcohol forced into said fuel cell by said early breath is measured by said fuel cell as a first value;

    wherein at least a portion of said later breath is displaced by said sampling system and provided to said fuel cell;

    wherein the amount of alcohol in the portion at said later breath displaced by said sampling system is measured by said fuel cell as a second value; and

    wherein if a ratio of said first value to said second value is above a predetermined threshold said breath alcohol tester disregards said second value.

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