Patent US3560737A successfully refreshed from Google Patents.
US3560737A
Expired / Lapsed
US
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Combustion products detector using a radioactive source and detector
Assignee: Honeywell Inc
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Filing: 1967-08-02
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Granted: 1971-02-02
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Expires: 1987-08-02
Abstract
Abstract A combustion detector of the ionization chamber type having a pair of spaced anode and cathode electrodes wherein the anode carries a radioactive source of beta particles for causing an ionization current in the interelectrode space. The electrodes are supported and positioned to provide an interelectrode space large enough to prevent most of the beta particles, emitted at the one electrode, from traversing the interelectrode space and reaching the other electrode while allowing some of the particles to do so. An electrostatic shield is provided by means of a third electrode surrounding the first two electrodes.
Inventors
- 👤 John D Skildum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:24
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/62; G01N27/64; G01N27/66; G08; G08B; G08B17/00; G08B17/10; G08B17/11; G08B17/113
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
11 words
Apparatus as in claim 1 wherein said radioactive source is Ni63.
Claim 2
Dependent Claim
45 words
Apparatus as in claim 1 wherein: said anode is in the form of a pin, said radioactive source is a coating on said anode, said cathode is in the form of a cylinder, and said supporting means supports said pin substantially coaxially inside said cylinder.
Claim 3
Dependent Claim
27 words
Apparatus as in claim 3 wherein: said radioactive source is Ni63; and said interelectrode space is greater than about 1 cm and less than about 5.3 cm.
Claim 4
Dependent Claim
13 words
Apparatus as in claim 4 wherein said interelectrode space is about 3 cm.
Claim 5
Dependent Claim
29 words
Apparatus as in claim 3: including a shielding electrode means; and wherein said support means supports said pin anode and said cylindrical cathode substantially coaxially within said shielding electrode.
Claim 6
Dependent Claim
42 words
Apparatus as in claim 6 and further including an electrical conductive housing for enclosing electrical circuitry to be operatively connected to said electrodes, said housing being electrically connected to said shielding electrode whereby the interior of said housing is substantially shielded electrically.
Claim 7
Dependent Claim
63 words
Apparatus as in claim 5 and further including voltage source means and interconnecting circuit means for operatively applying a voltage to said three electrodes whereby said shielding electrode is maintained at a reference potential, said anode is maintained negative with respect to said reference and positive with respect to said cathode, and said cathode is maintained substantially negative with respect to said reference.
Claim 8
Dependent Claim
118 words
Apparatus as in claim 5 wherein: the radius of said pin anode is greater than about 2 mm. and less than about 4.5 mm.; the radius of said cylindrical cathode is greater than about 1 cm. and less than about 5.3 cm.; said radioactive source is between about 0.05 mC and about 1.5 mC of Ni63; said shielding electrode is in the form of a cylinder having a radius greater than the radius of said cylindrical cathode and less than double the radius of said cylindrical cathode; and whereby said apparatus is adapted for substantially stable operation at about current saturation in air with an applied voltage between said anode and cathode of less than about 30 volts.
Claim 9
Dependent Claim
16 words
Apparatus as in claim 7 wherein the radius of said cylindrical cathode is about 3 cm.
Claim 10
Independent Claim
120 words
An apparatus for detecting products of combustion of the type where unidirectional potential is impressed across the electrodes comprising: an anode in pin shape having a radius from about 2 mm to about 4.5 mm, said anode having a coating of Ni63 for a radioactive source of a strength of 0.05 mC to 1.6 mC; a cathode in generally cylindrical form having a radius of from about 1 cm. up to about 5.3 cm.; means supporting said anode substantially coaxially inside said cathode; and said anode and said cathode adapted to be connected to a unidirectional potential whereby said apparatus is adapted to operate substantially at an applied voltage between the anode and cathode of less than about 30 volts.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |