US3900815A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Element for detection of combustible gases and smoke
Assignee: Individual
•
Filing: 1973-09-19
•
Granted: 1975-08-19
•
Expires: 1993-09-19
Abstract
Abstract A gas sensing element including a semiconductor material which changes its electroconductivity when it adsorbs a gas. In manufacture of the element, the semiconductor material is mixed with a material such as stearic acid which evaporates, sublimates or burns away when heated and produces a number of pores therein. When the mixture is applied to a suitable supporting material between a pair of electrodes and then heat-treated, the resultant gas sensing element has an improved rate of change of electroconductivity.
Inventors
- 👤 Naoyoshi Taguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:01
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
32 words
A GAS SENSING ELEMENT COMPRISING A PROUS BODY THAT INCLUDES A POWDERED TIN OXIDE SEMICONDUCTOR AND AT LEAST TWO ELECTRODES SECURED TO SAID BODY FOR THE PASSAGE OF AN ELECTRIC CURRENT THERETHROUGH.
Claim 2
Dependent Claim
32 words
A GAS SENSING ELEMENT COMPRISING A PROUS BODY THAT INCLUDES A POWDERED TIN OXIDE SEMICONDUCTOR AND AT LEAST TWO ELECTRODES SECURED TO SAID BODY FOR THE PASSAGE OF AN ELECTRIC CURRENT THERETHROUGH.
Claim 3
Dependent Claim
53 words
A gas sensing element as claimed in claim 1 wherein said Tin oxide is present in admixture with at least one organic material selected from wax, sugar, polyvinyl alcohol, resin, starch and stearic acid, and the porosity of the body of said gas sensing element is induced by volatilization of said organic material.
Claim 4
Dependent Claim
13 words
The gas element of claim 2 wherein said resin is an acrylic resin.
Claim 5
Dependent Claim
63 words
A gas sensing element comprising a porous body which includes a powdered tin oxide semiconductor and at least two electrodes secured to said body for the passage of an electric current therethrough, said tin oxide is present in admixture with an organic material, said porosity of said body is induced by volatilization of said organic material and said organic material is stearic acid.
Claim 6
Dependent Claim
63 words
A gas sensing element comprising a porous body which includes a powdered tin oxide semiconductor and at least two electrodes secured to said body for the passage of an electric current therethrough, said tin oxide is present in admixture with an organic material, said porosity of said body is induced by volatilization of said organic material and said organic material is stearic acid.
Claim 7
Dependent Claim
27 words
The gas element of claim 4 wherein said stearic acid is present in a proportion of 25 percent to 50 percent by weight of said tin oxide.
Claim 8
Dependent Claim
18 words
The gas element according to claim 5 wherein said mixture is heated at a temperature of about 700*C.
Claim 9
Dependent Claim
17 words
The gas element according to claim 6 wherein said mixture is heated in the presence of air.
References Cited (Backward Citations)
US3142811A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |