Portable sensor

• US 6,883,364 B2
• Filed: 08/28/2003
• Issued: 04/26/2005
• Est. Priority Date: 03/20/1998
• Status: Expired due to Fees

• Current Assignee: Smiths Detection - Pasadena Inc. (Smiths Group International Holdings Ltd.)
• Original Assignee: Smiths Detection - Pasadena Inc. (Smiths Group International Holdings Ltd.)
• Inventors: Sunshine, Steven A., Steinthal, M. Gregory, Boehr, Christopher K., Nakayama, Robert K.
• Primary Examiner(s): Garber, Charles
• Application Number:
  US10/652,980
• Publication Number:
  US 20040069046A1
• Time in Patent Office: 607 Days
• Field of Search: 73/232, 73/233, 73/233.4, 73/290.5, 73/310.5
• US Class Current: 73/23.34
• CPC Class Codes: G01N 33/0009 General constructional details of gas analysers, e.g. portable test equipment devices for withdrawing samples in the gaseous state G01N1/22
• CPC Class Codes: G01N 33/0031 comprising two or more sensors, e.g. a sensor array

Abstract

A vapor sensing device that is sufficiently small and lightweight to be handheld, and also modular so as to allow the device to be conveniently adapted for use in sensing the presence and concentration of a wide variety of specified vapors. The device provides these benefits using a sensor module that incorporates a sample chamber and a plurality of sensors located on a chip releasably carried within or adjacent to the sample chamber. Optionally, the sensor module can be configured to be releasably plugged into a receptacle formed in the device. Vapors are directed to pass through the sample chamber, whereupon the sensors provide a distinct combination of electrical signals in response to each. The sensors of the sensor module can take the form of chemically sensitive resistors having resistances that vary according to the identity and concentration of an adjacent vapor. These chemically sensitive resistors can each be connected in series with a reference resistor, between a reference voltage and ground, such that an analog signal is established for each chemically sensitive resistor. The resulting analog signals are supplied to an analog-to-digital converter, to produce corresponding digital signals. These digital signals are appropriately analyzed for vapor identification.

Claims

1. A sensor module configured for use with a sensing apparatus comprising a housing that defines a receptacle, the sensor module comprising:

a casing sized and configured to be received in the receptacle of the sensing apparatus;

a sample chamber;

an inlet port configured to be releasably engageable with a first port connection of the sensing apparatus when the sensor module is received in the receptacle, the inlet port receiving a test sample from the sensing apparatus and directing the test sample to the sample chamber;

an outlet port configured to discharge the test sample from the sample chamber;

at least one sensor located within or adjacent to the sample chamber and configured to provide a distinct response when exposed to one or more analytes located within the sample chamber; and

an electrical connector configured to be releasably engageable with a mating electrical connector of the sensing apparatus when the sensor module is received in the receptacle, the electrical connector transmitting the characteristic signals from the at least one sensor to the sensing apparatus, wherein the sensor module is configured to be received in the receptacle by concurrent engagement of the inlet port, the outlet port, and the electrical connector.

2. The sensor module of claim 1 wherein the outlet port is configured to be releasably engageable with a second port connection of the sensing apparatus when the sensor module is received in the receptacle of the sensing apparatus, the outlet port discharging the test sample from the sample chamber to the sensing apparatus.

3. The sensor module of claim 2 wherein the casing incorporates a rear wall that supports the inlet port, the outlet port, and the electrical connector.

4. The sensor module of claim 1 further comprising:

a substrate to which the plurality of sensors mounts.

5. The sensor module of claim 1 wherein the at least one sensor is arranged in a uniform manner within the sample chamber.

6. The sensor module of claim 1 wherein

each of the at least one sensor is implemented with a chemically sensitive resistor having a resistance that varies in a unique manner when exposed to one or more specified test samples;

and

the sensing apparatus includes an analyzer that detects a set of resistances of the at least one sensor and identifies the test sample based on the detected set of resistances.