Chemical agent detection

• US 7,941,288 B2
• Filed: 09/26/2006
• Issued: 05/10/2011
• Est. Priority Date: 05/11/2004
• Status: Active Grant

• Current Assignee: Leidos, Inc. (Leidos Holdings, Inc.)
• Original Assignee: Science Applications International Corporation
• Inventors: Rose, David, Ha, James, Haupt, Steven Gerald
• Primary Examiner(s): Bullock; In Suk
• Assistant Examiner(s): EOM, ROBERT J
• Application Number:
  US11/526,715
• Publication Number:
  US 20070161111A1
• Time in Patent Office: 1,687 Days
• Field of Search: 73/232, 73/233.4, 422/83, 422/98, 702/85, 702/87, 702/88, 702/100, 702/104
• US Class Current: 702/87
• CPC Class Codes: G01N 27/00 Investigating or analysing materials by the use of electric, electrochemical, or magnetic means G01N3/00 – G01N25/00 take precedence; measurement or testing of electric or magnetic variables or of electric or magnetic properties of materials G01R
• CPC Class Codes: G01N 33/0036 Specially adapted to detect a particular component all the other sub-groups of G01N33/0004 take precedence
• CPC Class Codes: Y10T 436/11 Automated chemical analysis

Abstract

A chemical agent detector with a a lesser demand sensor, a greater demand sensor, an inlet; and a manifold; and methods associated therewith. The manifold is positioned between the inlet and the sensors, and includes a first intake associated with the lesser demand sensor, a second intake associated with a greater demand sensor, and at least one restrictor. The first intake is placed closer to the inlet than the second intake, and the second intake is isolated from the inlet by at least one restrictor within the manifold. The intakes and restrictor are sized and positioned such that the ratio between: the conductance of the path from the inlet to the greater demand sensor to the conductance of the path between the sensors effectively isolates the lesser demand sensor from the effects of the greater demand sensor.

Claims

1. A method for mitigating desensitization of a first sensor in a chemical agent detection system comprising a plurality of sensors, including at least one first sensor operative to adjust its baseline to compensate for changes in ambient levels of a chemical agent and at least one second sensor not operative to so compensate, said method comprising:

determining a first sensor prior baseline and a second sensor prior baseline;

exposing the chemical agent detection system, including the first and second sensors, to an environment that may contain the chemical agent for sensing by the at least one first and second sensors;

adjusting the first sensor to a second baseline compensating for changes in ambient levels of the chemical agent;

indicating by the second sensor the presence of the chemical agent, wherein the first sensor does not indicate the presence of the chemical agent at the second baseline;

upon indication by the second sensor of the presence of the chemical agent, feeding this indication through a feedback mechanism to the at least one first sensor; and

adjusting the first sensor back to the first sensor prior baseline to mitigate false desensitization of the at least one first sensor.

2. The method of claim 1 further comprising the step of supplying the plurality of sensors with air from one inlet source.

3. The method of claim 2 further comprising the step of balancing the flow and volumetric demands of the plurality of sensors.