Flammable-gas sensor

• US 4,913,792 A
• Filed: 01/05/1989
• Issued: 04/03/1990
• Est. Priority Date: 07/28/1987
• Status: Expired due to Fees

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Sato, Satoru, Nagata, Yasuhiro, Furuya, Kiyoshi
• Primary Examiner(s): Kaplan, G. L.
• Application Number:
  US07/295,599
• Time in Patent Office: 453 Days
• Field of Search: 204/424, 204/425, 204/426, 204/412, 204/431, 204/432, 357/25
• US Class Current: 204/412
• CPC Class Codes: G01N 27/4045 for gases other than oxygen
• CPC Class Codes: G01N 27/4141 specially adapted for gases

Abstract

At the surface of an insulating substrate there are provided a working electrode and an counter electrode with a set space from the working electrode and a gas-permeable, proton-conductive film with which the surfaces of the electrodes are overlaid in such a manner as to form an integrated whole with the electrodes. By applying a set voltage between the two electrodes, flammable gas which has permeated the gas-permeable, proton conductive film is made to undergo oxidation and reduction at a surface of the working electrode, and protons which have been produced thereby move toward the counter electrode in the gas-permeable, proton-conductive film, so that the concentration of the flammable gas can be measured. A reference electrode can be provided for the purpose of stabilizing potential of the working electrode. A mechanism which is described above can be applied to a gas sensor of field-effect transistor type.

Claims

1. A flammable-gas sensor comprising:

an insulating substrate,

a working electrode provided at the surface of said insulating substrate,

a counter electrode provided at a surface of said insulating substrate and positioned with a set gap from said working electrode, and

a gas permeable, proton-conductive film which covers said working electrode and counter electrode and forms an integrated whole with said working electrode and counter electrode,

wherein said counter electrode is larger in area than said working electrode by a factor of 10 or more.

2. A flammable-gas sensor comprising:

an insulating substrate,

a working electrode provided at a surface of said insulating substrate,

a counter electrode provided at the surface of said insulating substrate and positioned with a set gap from said working electrode,

a reference electrode provided at the surface of said insulating substrate and positioned with set gaps from said working electrode and counter electrode, and

a gas permeable, proton-conductive film which covers said working electrode, counter electrode and reference electrode and forms an integrated whole with said working electrode, counter electrode and reference electrode,

wherein said reference electrode and counter electrode form coaxial circles with said working electrode at the center.

3. A flammable-gas sensor comprising:

an insulating substrate,

a working electrode provided at a surface of said insulating substrate,

a counter electrode provided at the surface of said insulating substrate and positioned with a set gap from said working electrode,

a reference electrode provided at the surface of said insulating substrate and positioned with set gaps from said working electrode and counter electrode, and

a gas permeable, proton-conductive film which covers said working electrode, counter electrode and reference electrode and forms an integrated whole with said working electrode, counter electrode and reference electrode,

wherein said reference electrode is positioned between said working electrode and counter electrode.