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US 5,689,059 AGranted
Selective gas sensor
AssigneeMotorola, Inc.
InventorsSeajin Oh, Jose Joseph, Neil Adams, Daniel A. Young, Gary K. Mui
Life of this patent
Estimating the term…
Abstract
A selective gas sensor (10) for detecting a particular compound, or group of compounds, such as non-methane hydrocarbons, within a high temperature gas stream (12) includes an oxygen generation system (14) positioned over an oxygen diffusion region (15). The oxygen generation system (14) and the oxygen diffusion region (15) provide oxygen through a medial temperature control zone (20) to a sensing element (16). The temperature and flux of hydrocarbon components within the high temperature gas stream (12) are regulated by components within the high temperature control zone (20) and by an external temperature control zone (22) in thermal contact with the sensing element (16).
Claims17
A selective gas sensor comprising:
- a heat exchanger;
- a mechanical support frame mounted to the heat exchanger;
- a sensing element in thermal contact with the heat exchanger;
- a gas-permeable membrane mounted to the mechanical support frame and positioned over the sensing element, the gas-permeable membrane configured for transporting a measurement gas therethrough, the measurement gas having a characteristic temperature;
- an electrochemical oxygen pump mounted to the mechanical support frame and positioned over the gas-permeable membrane,
- wherein a lower surface of the electrochemical oxygen pump is configured to deliver oxygen to the sensing element, and
- wherein an upper surface of the electrochemical oxygen pump is configured to receive the measurement gas;
- an insulating layer overlying the electrochemical oxygen pump;
- and
- a heating element overlying the insulating layer,
- wherein the heating element maintains the electrochemical oxygen pump at a first temperature, and
- wherein the heat exchanger maintains the sensing element at a second temperature, and
- wherein the second temperature is less than the characteristic temperature of the measurement gas at steady-state conditions and less than the first temperature;
- whereby the selective gas sensor is segregated into a plurality of distinct thermal management zones for optimal heat conduction within each zone.
11 more elements
A selective gas sensor comprising:
- a mechanical support frame having porous wall surfaces for the transport of a measurement gas therethrough;
- a porous, thermally-insulating member spanning the mechanical support frame and defining first and second chambers within the mechanical support frame;
- an electrochemical oxygen pump mounted within the first chamber and configured to provide oxygen gas into the first chamber and into the second chamber through the porous insulating member during operation of the selective gas sensor;
- a thermally conductive body;
- a sensing element positioned within the second chamber and in intimate contact with the thermally conductive body,
- wherein the thermally conductive body forms a portion of an interior surface of the second chamber, and
- wherein the sensing element is configured to detect a selected component of the measurement gas entering the second chamber through the porous insulating member;
- a porous metal cover overlying the mechanical support frame;
- a gas permeable thermal insulator surrounding a lower portion of the mechanical support frame and separating the lower portion of the mechanical support frame from the porous metal cover;
- and
- means for attaching the selective gas sensor to a metal wall surface;
- whereby the selective gas sensor is segregated into a plurality of distinct thermal management zones for optimal heat conduction within each zone.
9 more elements
A selective gas sensor comprising:
- a mechanical support frame having porous wall surfaces for the transport of a measurement gas therethrough, the measurement gas having a characteristic temperature;
- a porous insulating member spanning the mechanical support frame and defining first and second chambers within the mechanical support frame;
- an oxygen pump mounted within the first chamber;
- a sensing element having a lower surface in intimate contact with a thermally conductive body and an upper surface facing the second chamber,
- wherein the thermally conductive body functions to maintain an optimal characteristic temperature of the sensing element below the characteristic temperature of the measurement gas;
- and
- attachment means for securing the selective gas sensor to a wall surface;
- whereby the selective gas sensor is segregated into a plurality of distinct thermal management zones for optimal heat conduction within each zone.
5 more elements
A selective gas sensor comprising:
- a mechanical support frame cooperating with a thermally conductive body to define a cavity and configured for conveying a measurement gas into the cavity, the measurement gas having a characteristic temperature;
- a sensing element mounted to the thermally conductive body and facing the cavity;
- and
- a gas-permeable, thermally-insulating member spanning the mechanical support frame in spaced relationship with the sensing element and controlling a measurement gas flux to the sensing element,
- wherein the thermally conductive body is configured for transporting heat away from the cavity and cooperates with the gas-permeable, thermally-insulating member to maintain an optimal characteristic temperature of the sensing element below the characteristic temperature of the measurement gas;
- whereby the selective gas sensor is segregated into a plurality of distinct thermal management zones for optimal heat conduction within each zone.
3 more elements
Dependencies are inferred from the claim text.