Patent US3089196A successfully refreshed from Google Patents.
Patent US5268745A successfully refreshed from Google Patents.
US5268745A
Expired / Lapsed
US
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Light radiation absorption gas detector
Assignee: Siemens Plessey Controls Ltd
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Filing: 1992-04-24
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Granted: 1993-12-07
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Expires: 2012-04-24
Abstract
Abstract A light radiation absorption gas detector for detecting the presence of a specified gas, comprising a light source, a region containing a gas to be detected through which light from the source is passed, an interference filter having a substantially flat face and a light radiation absorption peak at a wavelength which facilitates detection of the specified gas, a shaft to which the filter is by means of arms secured for rotation so that a perpendicular to the flat face of the filter is at an angle to the axis of the rotation and light detector means responsive to light from the source which has passed through the region and the filter, for detecting predetermined light amplitude variations, wherein light from the source is arranged to be projected towards the filter at an angle offset from the axis of shaft rotation whereby a filter pass band which includes the said wavelength is scanned consequent upon rotation of the filter, thereby to produce amplitude variations of light in the presence within the region of the specified gas, whereby detection of the specified gas by the detector means is facilitated.
Inventors
- 👤 Brian A. Goody
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:26
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/42; G01J3/433; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01J3/12; G01J2003/1226; G01J2003/1243; G01J2003/4332; G01N21/35; G01N21/3504
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
238 words
A light radiation absorption gas detector for detecting the presence of a specified gas, comprising a light source, a region containing a gas to be detected through which a light beam from the source is passed, an interference filter having a substantially flat face and a light radiation absorption peak at a wavelength which facilitates detection of the specified gas, a shaft to which the filter is secured for rotation so that a perpendicular to the flat face of the filter is at an angle to the axis of the rotation, light detector means responsive to light from the source which has passed through the region and the filter for detecting predetermined light amplitude variations, and a light chopper or interrupter interposed between said source and said light detector means, wherein light from the source is directed via first lens means through the region, via second lens means from the region to the filter and via third lens means from the filter to the light detector means, and wherein light from the source is arranged to be projected towards the filter at an angle offset from the axis of shaft rotation whereby a filter pass band which includes the said wavelength is scanned consequent upon rotation of the filter, thereby to produce amplitude variations of light in the presence within the region of the specified gas, whereby detection of the specified gas by the detector means is facilitated.
Claim 2
Dependent Claim
238 words
A light radiation absorption gas detector for detecting the presence of a specified gas, comprising a light source, a region containing a gas to be detected through which a light beam from the source is passed, an interference filter having a substantially flat face and a light radiation absorption peak at a wavelength which facilitates detection of the specified gas, a shaft to which the filter is secured for rotation so that a perpendicular to the flat face of the filter is at an angle to the axis of the rotation, light detector means responsive to light from the source which has passed through the region and the filter for detecting predetermined light amplitude variations, and a light chopper or interrupter interposed between said source and said light detector means, wherein light from the source is directed via first lens means through the region, via second lens means from the region to the filter and via third lens means from the filter to the light detector means, and wherein light from the source is arranged to be projected towards the filter at an angle offset from the axis of shaft rotation whereby a filter pass band which includes the said wavelength is scanned consequent upon rotation of the filter, thereby to produce amplitude variations of light in the presence within the region of the specified gas, whereby detection of the specified gas by the detector means is facilitated.
Claim 3
Dependent Claim
23 words
A gas detector as claimed in claim 1, wherein the light chopper is interposed between the light source and the first lens means.
Claim 4
Dependent Claim
25 words
A gas detector as claimed in claim 1 wherein the filter is supported by arms which interrupt the light beam as the shaft is rotated.
Claim 5
Dependent Claim
24 words
A gas detector as claimed in claim 3 wherein the arms are positioned so as to interrupt the light beam synchronously with the chopper.
Claim 6
Dependent Claim
16 words
A gas detector as claimed in claim 3 wherein there are an even number of arms.
Claim 7
Dependent Claim
28 words
A gas detector as claimed in claim 1 wherein the chopper comprises rotary blades which interrupt the light beam at an even multiple of the shaft rotation rate.
Claim 8
Dependent Claim
56 words
A gas detector as claimed in claim 1, wherein the light detector means comprises an optical detector element effective to detect the light amplitude variations and a signal processor responsive to the said element for detecting electrical signal variations corresponding to the light amplitude variations produced in the presence within the region of the specified gas.
Claim 9
Dependent Claim
25 words
A gas detector as claimed in claim 7, wherein the signal processor is arranged to detect electrical signal variations in the form of amplitude modulation.
Claim 10
Dependent Claim
17 words
A gas detector as claimed in claim 1, further comprising a shaft rotating means comprising a motor.
Claim 11
Dependent Claim
27 words
A gas detector as claimed in claim 3, wherein the said filter is generally circular and supported at its circular peripheral edge by means of the arms.
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) | 1996-12-06 | 1997-06-07 | 1997-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-12-06 | 2001-06-07 | 2001-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-12-06 | 2005-06-07 | 2005-12-07 | $7700.00 | Window Closed / Lapsed |