US4792433A
Expired / Lapsed
US
⏱️ 0.0 years remaining
CO gas detecting device and circuit for driving the same
Assignee: Toshiba Corp
•
Filing: 1986-09-04
•
Granted: 1988-12-20
•
Expires: 2006-09-04
Abstract
Abstract Disclosed is a CO gas detecting device which comprises a CO gas sensor provided with a gas sensitive member made of SnO 2 , ZnO, Fe 2 O 3 or the like, a pair of electrodes provided on said gas sensitive member, and a catalyst layer comprising at least one kind of catalyst metals of Pt, Pd and Rh and at least one kind of carriers of Al 2 O 3 , ZrO 2 and SiO 2 , provided on said gas sensitive member; and a reference sensor substantially without sensitivity to CO gas provided with a gas sensitive member similar to the above gas sensitive member, a pair of electrodes provided on said gas sensitive member and a catalyst layer comprising Ag and at least one kind of carriers of Al 2 O 3 , ZrO 2 and SiO 2 , provided on said gas sensitive member. Also disclosed is a circuit for driving the device.
Inventors
- 👤 Masaki Katsura
- 👤 Masayuki Shiratori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:06
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0031; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N33/0036; G01N33/004
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
252 words
A CO gas detecting device comprising: a CO gas sensor provided with a gas sensitive member comprising an oxide semiconductor whose resistance value is changed when contacted with a reducing gas, a pair of electrodes provided on said gas sensitive member, and a catalyst layer comprising one or more catalyst metals selected from the group consisting of Pt, Pd and Rh and at least one carrier selected from the group consisting of Al 2 O 3 , ZrO 2 and SiO 2 , provided on said gas sensitive member; and a reference sensor substantially without sensitivity to CO gas provided with a gas sensitive member comprising an oxide semiconductor whose resistance value is changed when contacted with a reducing gas, a pair of electrodes provided on said gas sensitive member, and an insulative catalyst layer comprising Ag and at least one carrier selected from the group consisting of Al 2 O 3 , ZrO 2 and SiO 2 , provided on said gas sensitive member wherein said catalyst layers of each of said sensors comprise said catalyst metals in an amount of from about 0.05 to 20 wt. % based on the catalyst carrier in a thick film of from 10 to 50 μm and from about 1 to 90 wt. % based on the catalyst carrier in a thin film of from about 5 to 1000 nm, such that the amounts of said catalyst metals are below levels at which the electroconductivity of said layers hampers measurement of said resistance value.
Claim 2
Dependent Claim
252 words
A CO gas detecting device comprising: a CO gas sensor provided with a gas sensitive member comprising an oxide semiconductor whose resistance value is changed when contacted with a reducing gas, a pair of electrodes provided on said gas sensitive member, and a catalyst layer comprising one or more catalyst metals selected from the group consisting of Pt, Pd and Rh and at least one carrier selected from the group consisting of Al 2 O 3 , ZrO 2 and SiO 2 , provided on said gas sensitive member; and a reference sensor substantially without sensitivity to CO gas provided with a gas sensitive member comprising an oxide semiconductor whose resistance value is changed when contacted with a reducing gas, a pair of electrodes provided on said gas sensitive member, and an insulative catalyst layer comprising Ag and at least one carrier selected from the group consisting of Al 2 O 3 , ZrO 2 and SiO 2 , provided on said gas sensitive member wherein said catalyst layers of each of said sensors comprise said catalyst metals in an amount of from about 0.05 to 20 wt. % based on the catalyst carrier in a thick film of from 10 to 50 μm and from about 1 to 90 wt. % based on the catalyst carrier in a thin film of from about 5 to 1000 nm, such that the amounts of said catalyst metals are below levels at which the electroconductivity of said layers hampers measurement of said resistance value.
Claim 3
Dependent Claim
43 words
The CO gas detecting device according to claim 1, wherein the oxide semiconductor used in each of said gas sensitive members comprises at least one oxide semiconductor selected from the group consisting of SnO 2 , ZnO and Fe 2 O 3 .
Claim 4
Dependent Claim
35 words
The CO gas detecting device according to claim 2, wherein the oxide semiconductor further comprises Nb or Sb within the range of from 0.005 to 0.05 in terms of atomic ratio to the oxide semiconductor.
Claim 5
Dependent Claim
20 words
The CO gas detecting device according to claim 1, wherein each of said gas sensitive members is a thin film.
Claim 6
Dependent Claim
27 words
The CO gas detecting device according to claim 4, wherein each of said gas sensitive member has a film thickness of from 100 Å to 1 μm.
Claim 7
Dependent Claim
32 words
The CO gas detecting device according to claim 4, wherein each of said gas sensitive members comprises a SnO 2 thin film or a SnO 2 thin film comprising Nb or Sb.
Claim 8
Dependent Claim
24 words
The CO gas detecting device according to claim 1, wherein the catalyst carrier of said CO gas sensor comprises Al 2 O 3 .
Claim 9
Dependent Claim
22 words
The CO gas detecting device according to claim 1, wherein the catalyst layer of said CO gas sensor comprises a thick film.
Claim 10
Dependent Claim
47 words
The CO gas detecting device according to claim 1, wherein the catalyst metal of said CO gas sensor is a material selected from the group consisting of Pt-Pd, Pd-Rh and Pt-Rh wherein the proportion of Pt/Pd, Rh/Pd and Rh/Pt=0.05 to 1.0, respectively, in terms of atomic ratio.
Claim 11
Dependent Claim
34 words
The CO gas detecting device according to claim 1, the catalyst layer of said CO gas sensor further comprising a moisture protective metal containing 0.05 to 20 wt.% of Ag based on the carrier(s).
Claim 12
Dependent Claim
40 words
The CO gas detecting device according to claim 1, further including another layer comprising at least one carrier of Al 2 O 3 , ZrO 2 and SiO 2 and 0.05 to 20 wt.% of Ag based on the carrier(s).
Claim 13
Dependent Claim
26 words
The CO gas detecting device according to claim 1, wherein the carrier of the catalyst layer of said reference sensor is Al 2 O 3 .
Claim 14
Dependent Claim
21 words
The CO gas detecting device according to claim 1, wherein the catalyst layer of said reference sensor comprises a thick film.
Claim 15
Dependent Claim
153 words
The CO gas detecting device according to claim 1, wherein the CO gas sensor and the reference sensor are secured and suspended within a cut area provided in an insulating supporting plate comprising a glass epoxy resin or Al 2 O 3 and having conductor patterns comprising Cu foil formed on both of front and rear surfaces thereof, by means of lead wires in such a manner that they are respectively located on the faces corresponding to the front surface and the rear surface of the supporting plate or that they are provided in parallel on the same face corresponding to one surface of the supporting plate; said supporting plate being provided with a cut at an area adjacent to and along one side of the plug portion in such a manner that it may be inserted to an external plug socket having a shape corresponding to the sectional shape of the plug.
Claim 16
Dependent Claim
77 words
A circuit for driving the CO gas detecting device of claim 1, which comprises the CO gas sensor connected to a resistance-voltage converting circuit, the reference sensor connected to another resistance-voltage converting circuit which is further connected to an alarm level-setting circuit, a voltage comparison circuit to compare signals from the CO gas sensor and signals from the alarm level-setting circuit, and an alarm circuit to which an alarm signal from the voltage comparison circuit is inputted.
Claim 17
Dependent Claim
26 words
The CO gas detecting device according to claim 1, wherein said CO sensor and said reference sensor have similar sensitivities to reducing gases other than CO.
References Cited (Backward Citations)
US4000089A
Cited
US3961248A
Cited
US4033169A
Cited
DE2636178A1
Cited
DE2746381A1
Cited
US4107019A
Cited
US4259292A
Cited
US4251225A
Cited
US4223550A
Cited
US4193964A
Cited
JPS54134697A
Cited
DE3005528A1
Cited
US4343768A
Cited
EP0046989A2
Cited
GB2086583A
Cited
US4481499A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-20 | 1992-06-20 | 1992-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-20 | 1996-06-20 | 1996-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-20 | 2000-06-20 | 2000-12-20 | $7700.00 | Window Closed / Lapsed |