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US4485665A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detection of toxic vapors
Assignee: Department of National Defence
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Filing: 1976-03-01
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Granted: 1984-12-04
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Expires: 1996-03-01
Abstract
Abstract An improved apparatus is provided for detecting the presence of small concentrations of one gas, e.g. a poisonous or other noxious gas, in another gas, e.g. air. The gaseous mixture, e.g. contaminated air is caused to contact a colorimetric detector, e.g., an enzyme, supported on or in a support surface. The improvement involves having a sampling head for the vapor detection apparatus including (a) a detection chamber; (b) an opening permitting the insertion of a vapor detector into the detection chamber; (c) an inlet to the detection chamber, such inlet including a critical orifice directed towards the detection chamber; (d) an outlet from the detection chamber; (e) an interrelated coordination of the orifice diameter and the pressure drop across the orifice to cause a gas to pass through the critical orifice at a jet stream velocity approaching the velocity of sound, at that temperature (f) a vapor detector adapted to be positioned in the detection chamber via the opening (b), and (g) an air by-pass interconnecting the inlet and the outlet such that, in operation most of the air stream is directed from the critical orifice against, but not through the detector, and through the air by-pass through the outlet.
Inventors
- 👤 J. James Norman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:51
CPC Classifications
G; G01; G01N; G01N1/00; G01N1/02; G01N1/22; G01N1/24; G01N2001/242; G01N2001/244; Y; Y10; Y10T; Y10T436/00; Y10T436/25; Y10T436/25875
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
157 words
In a vapour detection apparatus, a sampling head having a main body portion including: (a) a detection chamber; (b) means for the insertion of a vapour detector into the detection chamber; (c) inlet means to the detection chamber, said inlet means including a critical orifice directed towards the detection chamber; (d) outlet means from the detection chamber; (e) means for causing a gas to pass through the critical orifice at a jet stream velocity approaching the velocity of sound in that gas at that temperature by co-ordinating the orifice diameter and the pressure drop across the orifice; (f) a vapour detector adapted to be positioned in said chamber via said insertion means; and (g) an air by-pass means interconnecting said inlet means and said outlet means, such that in operation most of the air stream is directed from said critical orifice, against but not through the detector, and through the air by-pass means to said outlet means.
Claim 2
Dependent Claim
157 words
In a vapour detection apparatus, a sampling head having a main body portion including: (a) a detection chamber; (b) means for the insertion of a vapour detector into the detection chamber; (c) inlet means to the detection chamber, said inlet means including a critical orifice directed towards the detection chamber; (d) outlet means from the detection chamber; (e) means for causing a gas to pass through the critical orifice at a jet stream velocity approaching the velocity of sound in that gas at that temperature by co-ordinating the orifice diameter and the pressure drop across the orifice; (f) a vapour detector adapted to be positioned in said chamber via said insertion means; and (g) an air by-pass means interconnecting said inlet means and said outlet means, such that in operation most of the air stream is directed from said critical orifice, against but not through the detector, and through the air by-pass means to said outlet means.
Claim 3
Dependent Claim
23 words
The vapour detection apparatus of claim 1 wherein the critical orifice is provided in a separate nozzle secured into the main body portion.
Claim 4
Dependent Claim
25 words
The vapour detection apparatus of claim 2 wherein the means (b) for insertion of a vapour detector is a slot communicating with the detection chamber.
Claim 5
Dependent Claim
48 words
The vapour detection apparatus of claim 2 wherein the gas is air, and wherein the means (e) for causing the air to pass through the critical orifice is a suction pump, to which the outlet means (d) is connected by detachable fitting means on the main body portion.
Claim 6
Dependent Claim
25 words
The vapour detection apparatus of claim 4 including a one-way flap valve associated with the outlet means (d) to permit air to flow outwardly only.
Claim 7
Dependent Claim
28 words
The vapour detection apparatus of claim 1 wherein the gas is air and wherein the critical orifice is intergral with the air inlet means to the detection chamber.
Claim 8
Dependent Claim
37 words
The vapour detection apparatus of claim 6 wherein the main body is provided as two hingedly connected parts with the air inlet means (c) in one part, and the air outlet means (d) in the other part.
Claim 9
Dependent Claim
29 words
The vapour detection apparatus of claim 7 wherein the means (b) for the insertion of the vapour detector is a recess between the two parts of the main body.
Claim 10
Dependent Claim
19 words
The vapour detection apparatus of claim 7 including gasket means disposed between the two parts of the main body.
Claim 11
Dependent Claim
42 words
The vapour detection apparatus of claim 6 wherein the means (e) for causing the air to pass through the critical orifice is a suction pump, to which the outlet means (d) is connected by detachable fitting means on the main body portion.
Claim 12
Dependent Claim
25 words
The vapour detection apparatus of claim 10 including a one-way flap valve associated with the outlet means (d) to permit air to flow outwardly only.
Claim 13
Dependent Claim
28 words
The vapour detection apparatus of claim 1, wherein the detection chamber (a) is provided as a recess between the main body portion and a cap detachably secured thereto.
Claim 14
Dependent Claim
42 words
The vapour detection apparatus of claim 12 wherein the detection chamber (a) is provided between the body and a vapour detector disposed between the cap and the body and is sealed by gaskets in contact with the body and the vapour detector.
Claim 15
Dependent Claim
22 words
The vapour detection apparatus of claim 13 wherein the critical orifice is provided in a separate nozzle into the main body portion.
Claim 16
Dependent Claim
42 words
The vapour detection apparatus of claim 14 wherein the means (e) for causing the air to pass through the critical orifice is a suction pump, to which the outlet means (d) is connected by detachable fitting means on the main body portion.
Claim 17
Dependent Claim
25 words
The vapour detection apparatus of claim 15 including a one-way flap valve associated with the outlet means (d) to permit air to flow outwardly only.
Claim 18
Dependent Claim
106 words
A one piece sampling head for a vapour detection apparatus as claimed in claim 1 in which the gas is air and including a generally cylindrical body provided with a sampling chamber; a slotted inlet provided with a self-sustaining vapour detection element disposed in said sampling chamber; an inlet to said sampling chamber; an outlet from said sampling chamber; means for connecting the outlet from said sampling chamber to a pump for drawing air therethrough; and a nozzle disposed in said inlet to said sampling chamber, said nozzle having a critical orifice to accelerate the air passing therethrough to a velocity approaching the velocity of sound.
Claim 19
Dependent Claim
123 words
A two piece sampling head for a vapour detection apparatus as claimed in claim 1, in which the gas is air and including a pair of hinged plates, a sampling chamber recessed in said plates within facing surfaces thereof; a slotted inlet to said sampling chamber, said inlet being provided with a self-sustaining vapour detection element disposed in said sampling chamber; sealing gasket means disposed against one face of said vapour detection element; and inlet nozzle to said sampling chamber, said nozzle having a critical orifice to accelerate the air passing therethrough to a velocity approaching the velocity of sound; and outlet from said sampling chamber; and means for connecting the outlet from said sampling chamber to a pump for drawing air therethrough.
Claim 20
Dependent Claim
136 words
A two piece sampling head for a vapour detector apparatus as claimed in claim 1, in which the gas is air and including a generally cylindrical externally threaded body and an internally threaded cylindrical cap operatively associated therewith, and defining, therebetween, a sampling chamber; a slotted inlet provided with a self-sustaining vapour detection element disposed in said sampling chamber; a pair of O-ring gasket members contacting said vapour detection element to provide an air tight sampling chamber; an inlet to said sampling chamber; an outlet from said sampling chamber; means for connecting the outlet from said sampling chamber to a pump for drawing air therethrough; and a nozzle disposed in said inlet to said sampling chamber, said nozzle having a critical orifice to accelerate the air passing therethrough to a velocity approaching the velocity of sound.
Claim 21
Dependent Claim
90 words
A two piece sampling head for a vapour detection apparatus as claimed in claim 1, in which the gas is air and including a generally cylindrical externally threaded body and an internally threaded cylindrical cap operatively associated therewith, and defining, therebetween, a sampling chamber; a slotted inlet provided with a self-sustaining vapour detection element disposed in said sampling chamber, said vapour detection element comprising a self-sustaining element; an inset aperture formed therethrough; and a bibulous element impregnated with a suitable vapour detection element covering one face of said inset aperture.
Claim 22
Dependent Claim
45 words
The vapour detection apparatus of claim 1, wherein said detector chamber includes a contact channel in which the air stream from the critical orifice is directed against the detector, and a by-pass channel downstream of said detector chamber in fluid communication with said outlet means.
References Cited (Backward Citations)
US2662393A
Cited
US3166938A
Cited
US3507622A
Cited
US3451901A
Cited
US3628915A
Cited
US3699814A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-12-04 | 1988-06-04 | 1988-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-04 | 1992-06-04 | 1992-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-04 | 1996-06-04 | 1996-12-04 | $7700.00 | Window Closed / Lapsed |