Flow gap gas distribution adapter for an electrochemical gas sensor

• US 6,793,786 B2
• Filed: 03/28/2002
• Issued: 09/21/2004
• Est. Priority Date: 07/13/2001
• Status: Active Grant

• Current Assignee: Dragerwerk AG
• Original Assignee: Dragerwerk AG
• Inventors: Kiesele, Herbert, Mett, Frank, Kunz, Rainer, Kühn, Uwe
• Primary Examiner(s): Olsen, Kaj K.
• Application Number:
  US10/109,477
• Publication Number:
  US 20030010635A1
• Time in Patent Office: 908 Days
• Field of Search: 204/409, 204/415, 205/782, 205/782.5, 205/783
• US Class Current: 204/409
• CPC Class Codes: G01N 27/404 Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid , e.g. Clark-type oxygen sensors
• 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

Abstract

An adapter (1) and electrochemical gas sensor (2) is provided with an electrochemical gas sensor housing (14) accommodating an electrolyte (13), with at least one measuring electrode (12) arranged therein and with a membrane (11), which screens the measuring electrode (12) from a measured gas and is permeable to the measured gas.

The measuring sensitivity of an electrochemical gas sensor is increased by the adapter (1) having a gas-impermeable surface (15) extending in parallel to and at a spaced location from the membrane (11). The adapter (1) and the membrane (11) form a flow gap (10) for the measured gas delivered by a pump. The adapter (1) may be plugged onto the electrochemical sensor (2) at its outer edge (1a). The measured gas enters through a central opening (17), expands in the flow gap (10) radially to the outside and leaves same via the ring-shaped gap (16).

Claims

1. An adapter and an electrochemical gas sensor, comprising:

an electrochemical gas sensor housing accommodating an electrolyte;

a measuring electrode arranged in the housing in contact with the electrolyte;

a membrane that screens the measuring electrode and the electrolyte from the measured gas and is permeable to the measured gas for mass exchange between the electrolyte and the measured gas;

an adapter with a gas-impermeable surface, the adapter and the electrochemical gas sensor housing forming an inlet for feeding in a measured gas to the side of the membrane located opposite the measuring electrode, the adapter and the housing forming an outlet for removing the measured gas from the side of the membrane located opposite the measuring electrode, the adapter gas-impermeable surface extending in parallel to and at a spaced location from the membrane between the inlet and the outlet for the measured gas, the adapter and the membrane cooperating to form a flow gap for the measured gas, wherein the flow gap has a rotationally symmetrical design with the membrane shaped as an outer cylinder jacket formed around an axis of rotation and with the gas-impermeable surface shaped as an inner cylinder jacket and arranged coaxially with the outer cylinder jacket.

2. An adapter and an electrochemical gas sensor in accordance with claim 1, wherein a gas-impermeable outer cylinder bottom extending at right angles to the axis of rotation limits the outer cylinder jacket and an inner cylinder bottom which is extending at right angles to the axis of rotation and has a central hole and limits the inner cylinder jacket as an inlet or outlet for the measured gas, wherein the inner cylinder bottom and the outer cylinder bottom are arranged at spaced locations from one another.

3. An adapter and an electrochemical gas sensor, comprising:

an electrochemical gas sensor housing accommodating an electrolyte;

a measuring electrode arranged in the housing in contact with the electrolyte;

a membrane that screens the measuring electrode and the electrolyte from the measured gas and is permeable to the measured gas for mass exchange between the electrolyte and the measured gas;

an adapter with a gas-impermeable surface, the adapter and the electrochemical gas sensor housing forming an inlet for feeding in a measured gas to the side of the membrane located opposite the measuring electrode, the adapter and the housing forming an outlet for removing the measured gas from the side of the membrane located opposite the measuring electrode, the adapter gas-impermeable surface extending in parallel to and at a spaced location from the membrane between the inlet and the outlet for the measured gas, the adapter and the membrane cooperating to form a flow gap for the measured gas, wherein the flow gap has a rotationally symmetrical design with the gas-impermeable surface formed as an outer cylinder jacket around the axis of rotation and with the membrane formed as an inner cylinder jacket and arranged coaxially with the outer cylinder jacket.

4. An adapter and an electrochemical gas sensor in accordance with claim 3, wherein a gas-impermeable outer cylinder bottom extending at right angles to the axis of rotation limits the outer cylinder jacket and an inner cylinder bottom extending at right angles to the axis of rotation and limiting the inner cylinder jacket, wherein the inner cylinder bottom and the outer cylinder bottom are arranged at spaced locations from one another.

5. An adapter and an electrochemical gas sensor in accordance with claim 3, wherein the adapter is detachably connected to the housing of the electrochemical gas sensor by a plug connection.

6. An adapter and an electrochemical gas sensor in accordance with claim 3, wherein the adapter is firmly connected to the electrochemical gas sensor housing and is manufactured in one piece as part of the electrochemical gas sensor housing.

7. An adapter and an electrochemical gas sensor in accordance with claim 3, wherein the flow gap has a gap width of at most 2.5 mm.

8. An adapter and electrochemical gas sensor combination, comprising:

an electrochemical gas sensor housing accommodating an electrolyte;

a measuring electrode arranged in said housing;

a membrane that screens the measuring electrode and electrolyte from the measured gas and is permeable to the measured gas; and

an adapter, the adapter and the electrochemical gas sensor housing forming an inlet for feeding in a measured gas to a side of the membrane located opposite the measuring electrode and electrolyte, the adapter and the housing forming an outlet for removing the measured gas from a side of the membrane located opposite the measuring electrode and electrolyte, the adapter having a gas-impermeable surface extending in parallel to and at a spaced location from the membrane between the inlet and the outlet for the measured gas, the adapter and the membrane cooperating to form a flow gap for the measured gas, wherein the flow gap has a radially symmetrical design with the membrane shaped as a circular disk and with the gas-impermeable surface shaped as a circular disk with a central opening as the inlet or outlet for the measured gas.

9. A combination in accordance with claim 8, wherein a ring-shaped gap is provided between the edge of the gas-impermeable surface shaped as a circular disk with a central opening and an adapter housing portion.

10. An adapter and electrochemical gas sensor combination, comprising:

an electrochemical gas sensor housing accommodating an electrolyte;

a measuring electrode arranged in said housing;

a membrane that screens the measuring electrode and electrolyte from the measured gas and is permeable to the measured gas; and

an adapter, the adapter and the electrochemical gas sensor housing forming an inlet for feeding in a measured gas to a side of the membrane located opposite the measuring electrode and electrolyte, the adapter and the housing forming an outlet for removing the measured gas from a side of the membrane located opposite the measuring electrode and electrolyte, the adapter having a gas-impermeable surface extending in parallel to and at a spaced location from the membrane between the inlet and the outlet for the measured gas, the adapter and the membrane cooperating to form a flow gap for the measured gas, wherein the flow gap has a rotationally symmetrical design with the membrane shaped as an outer cylinder jacket formed around an axis of rotation and with the gas-impermeable surface shaped as an inner cylinder jacket and arranged coaxially with the outer cylinder jacket.

11. A combination in accordance with claim 10, wherein a gas-impermeable outer cylinder bottom extending at right angles to the axis of rotation limits the outer cylinder jacket and a inner cylinder bottom extending at right angles to the axis of rotation has a central hole and limits the inner cylinder jacket as an inlet or outlet for the measured gas, wherein the inner cylinder bottom and the outer cylinder bottom are arranged at spaced locations from one another.

12. An adapter and electrochemical gas sensor combination, comprising:

an electrochemical gas sensor housing accommodating an electrolyte;

a measuring electrode arranged in said housing;

a membrane that screens the measuring electrode and electrolyte from the measured gas and is permeable to the measured gas; and

an adapter, the adapter and the electrochemical gas sensor housing forming an inlet for feeding in a measured gas to a side of the membrane located opposite the measuring electrode and electrolyte, the adapter and the housing forming an outlet for removing the measured gas from a side of the membrane located opposite the measuring electrode and electrolyte, the adapter having a gas-impermeable surface extending in parallel to and at a spaced location from the membrane between the inlet and the outlet for the measured gas, the adapter and the membrane cooperating to form a flow gap for the measured gas, wherein the flow gap has a rotationally symmetrical design with the gas-impermeable surface formed as an outer cylinder jacket around the axis of rotation and with the membrane formed as an inner cylinder jacket and arranged coaxially with the outer cylinder jacket.

13. A combination in accordance with claim 12, wherein a gas-impermeable outer cylinder bottom extending at right angles to the axis of rotation limits the outer cylinder jacket and a inner cylinder bottom extending at right angles to the axis of rotation and limiting the inner cylinder jacket, wherein the inner cylinder bottom and the outer cylinder bottom are arranged at spaced locations from one another.

14. A combination in accordance with claim 12, wherein the flow gap has a gap width of at most 2.5 mm.

15. An electrochemical gas sensing system comprising:

an electrochemical gas sensor housing defining an electrolyte space;

electrolyte disposed in said electrolyte space;

a measuring electrode arranged in said electrolyte space;

a membrane closing off said electrolyte space and defining a gas permeable liquid impermeable barrier screening said electrolyte and said measuring electrode with respect to a gas space outside of said electrolyte space;

an adapter, said adapter and the electrochemical gas sensor housing forming an inlet for feeding in a measured gas to the gas space at a side of the membrane located opposite said electrolyte space, the adapter and the housing forming an outlet for removing the measured gas the gas space opposite said electrolyte space, the adapter having a gas-impermeable surface extending in parallel to and at a spaced location from the membrane to form a gas flow gap between the gas inlet and the gas outlet the flow gap having a rotationally symmetrical design with the gas-impermeable surface formed as one of an outer cylinder jacket around the axis of rotation and an inner cylinder jacket arranged coaxially with the outer cylinder jacket and with the membrane formed as the other of the outer cylinder jacket and the inner cylinder jacket; and

a pump connected to one of said gas inlet and said gas outlet for causing measured gas to flow through said gas flow gap.