US3790800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiation detection system with fail safe feature
Assignee: Honeywell Inc
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Filing: 1972-12-27
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Granted: 1974-02-05
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Expires: 1992-12-27
Abstract
Abstract An internal ionization radiation sensor operates to discharge a capacitor in the presence of incident radiation. The recharging current is sensed by a threshold output device. In one embodiment, the threshold output device is prevented from receiving the additional current necessary to be triggered if the radiation sensor fails in the runaway mode. The additional current to trigger the threshold output device is supplied from a second capacitor which is prevented from charging by a runaway radiation sensor.
Inventors
- 👤 L Linner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:14
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/18
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
173 words
An ultraviolet detection system employing a radiation sensor operating through internal gas ionization comprising: a radiation sensor discharge circuit having a supply capacitor joined in parallel across a series arrangement of said radiation sensor and a first current limiting means, said supply capacitor having first and second terminals at which it is so joined, whereby said radiation sensor, upon breakdown initiated by received radiation, discharges said supply capacitor through said first current limiting means, said radiation sensor discharge circuit to be connected to external components selectively at one of said first and second terminals; second current limiting means connected in series with said radiation sensor discharge circuit; current detection means connected in series with said radiation sensor discharge circuit and having a first current threshold value which currents through said current detection means must exceed for an output to be initiated therefrom; and connection means adapted to connect said radiation sensor discharge circuit, said second current limiting means and said current detection means connected as said above to a source of direct current.
Claim 2
Dependent Claim
173 words
An ultraviolet detection system employing a radiation sensor operating through internal gas ionization comprising: a radiation sensor discharge circuit having a supply capacitor joined in parallel across a series arrangement of said radiation sensor and a first current limiting means, said supply capacitor having first and second terminals at which it is so joined, whereby said radiation sensor, upon breakdown initiated by received radiation, discharges said supply capacitor through said first current limiting means, said radiation sensor discharge circuit to be connected to external components selectively at one of said first and second terminals; second current limiting means connected in series with said radiation sensor discharge circuit; current detection means connected in series with said radiation sensor discharge circuit and having a first current threshold value which currents through said current detection means must exceed for an output to be initiated therefrom; and connection means adapted to connect said radiation sensor discharge circuit, said second current limiting means and said current detection means connected as said above to a source of direct current.
Claim 3
Dependent Claim
189 words
The system of claim 1 wherein: said first and second current limiting means limit current passing through said current detection means such that said first current threshold value cannot be reached but that a lesser second current threshold value can be exceeded, said current detection means operating such that said output can be maintained by currents exceeding said second current threshold value; said current detection means is immediately connected to a selected one of said first and second terminals; and a protective triggering circuit is connected in parallel across said radiation sensor discharge circuit and said current detection means connected as said, said protective triggering circuit having a triggering capacitor joined in series with a parallel arrangement of a third current limiting means and a voltage threshold means, said trigger capacitor so joined at a third terminal thereof and said voltage threshold means having a voLtage threshold value which voltages across said voltage threshold means must exceed before appreciable current can be conducted therethrough, whereby sufficient current can be supplied to said current detection means to exceed said first current threshold value when said triggering capacitor becomes sufficiently charged.
Claim 4
Dependent Claim
24 words
The system of claim 2 wherein rectifying means is connected between said selected one of said first and second terminals and said third terminal.
Claim 5
Dependent Claim
30 words
The system of claim 3 wherein reflector means are employed to increase incident radiation reaching said radiation sensor by reflecting incident radiation intercepted in an area to said radiation sensor.
Claim 6
Dependent Claim
16 words
The system of claim 3 wherein said first, second and third current limiting means are resistors.
Claim 7
Dependent Claim
13 words
The system of claim 3 wherein said current detection means is a relay.
Claim 8
Dependent Claim
14 words
The system of claim 3 wherein said voltage threshold means is a neon tube.
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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |