US3925022A
Expired / Lapsed
US
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Detecting apparatus
Assignee: Marsland Engineering Ltd
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Filing: 1974-09-26
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Granted: 1975-12-09
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Expires: 1994-09-26
Abstract
Abstract The apparatus comprises a collector assembly having a passage filled with a solid adsorbant which is capable of adsorbing the specific vapour together with other vapours in the atmospheric sample and which is also capable of being readily heated to desorb the adsorbed vapours. The outlet of the passage of the collector assembly is connectable to a partition column, which separates the desorbed vapours. The partition column is connected to a detector, which detects the specific vapour among the vapours separated by the partition column. The collector assembly is movable between a sampling position where the passage is communicated with the atmosphere and unconnected to the partition column, and an analyzing position where the passage is connected to the partition column and unconnected to the atmosphere. The apparatus also includes means to draw the atmospheric sample over the adsorbant when the collector assembly is in the sampling position, heating means for heating the adsorbant when the collector assembly is moved to the analyzing position and a carrier gas source connectable to the inlet of the collector assembly to provide a flow of a carrier gas so that the carrier gas carries the vapours desorbed from the adsorbant to the partition column for separation and the separated vapours to the detector for detection of the specific vapour. The apparatus is useful for detection of hazardous or toxic materials or substances being used for illegal purposes, such as explosives and narcotics, which emit their vapours.
Inventors
- 👤 Lane Crawford Showalter
- 👤 John Leslie Brokenshire
- 👤 Geoffrey Brian Watts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:14
CPC Classifications
G; G01; G01N; G01N30/00; G01N30/02; G01N30/88; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0036; G01N33/0045
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
238 words
AN APARATUS FOR DETECTING A TRACE OF A SPECIFIC VAPOR IN AN ATMOSPHERIC SAMPLE; COMPRISING A. A COLLECTOR ASSEMBLY HAVING AN INLET AND AN OUTLET AND A PASSAGE EXTENDING FROM THE INLET TO THE OUTLET, THE PASSAGE BEING FILLED WITH A SOLID ABSORBANT WHICH IS CAPABLE OF ABSORBING THE SPECIFIC VAPOR AND TOGETHER WITH OTHER VAPORS IN THE ATMOSPHERIC SAMPLE AND WHICH IS CAPABLE OF BEING READLY HEATED TO DESORB THE ABSORBED VAPORS, B. HEATING MEANS FOR HEATING THE ABSORBANT TO DESORB THE ABSORBED VAPOURS, C. A PARTITION COLUMN CONNECTABLE TO THE OUTLET OF THE PASSTAGE FOR SEPARATING THE DESORBED VAPOURS, D. A DETECTOR CONNECTED TO THE PARTITION COLUMN FOR DETECTING THE SPECIFIC VAPOUR AMONG THE SEPARATED VAPOURS, E. A CARRIER GAS SOURCE CONNECTABLE TO THE INLET OF THE PASSAGE TO PROVIDE A FLOW OF A CARRIER GAS SO THAT THE CARRIER GAS PASSES THE DESORBED VAPOURS TO THE PARTITION COLUMN FOR SEPARATION AND THE SEPARATED VAPOURS TO THE DETECTOR FOR DETECTION OF THE SPECIFIC VAPOUR, F. SAID COLLECTOR ASSEMBLY BEING MOVABLE BETWEEN A SAMPLING POSITION WHERE THE PASSAGE IS COMMUNICATED WITH THE ATMOSPHERE WHILE DISCONNECTED TO THE PARTITION COLUMN AND THE CARRIER GAS SOURCE, AND AN ANALYZING POSITION WHERE THE PASSAGE IS CONNECTED TO THE PARTITION COLUMN AND THE CARRIER GAS SOURCE WHILE DISCONNECTED TO THE ATMOSPHERE, AND G. MEANS TO DRAW THE ATMOSPHERE SAMPLE OVER THE ABSORBANT WHEN THE COLLECTOR ASSEMBLY IS IN THE SAMPLING POSITION.
Claim 2
Dependent Claim
238 words
AN APARATUS FOR DETECTING A TRACE OF A SPECIFIC VAPOR IN AN ATMOSPHERIC SAMPLE; COMPRISING A. A COLLECTOR ASSEMBLY HAVING AN INLET AND AN OUTLET AND A PASSAGE EXTENDING FROM THE INLET TO THE OUTLET, THE PASSAGE BEING FILLED WITH A SOLID ABSORBANT WHICH IS CAPABLE OF ABSORBING THE SPECIFIC VAPOR AND TOGETHER WITH OTHER VAPORS IN THE ATMOSPHERIC SAMPLE AND WHICH IS CAPABLE OF BEING READLY HEATED TO DESORB THE ABSORBED VAPORS, B. HEATING MEANS FOR HEATING THE ABSORBANT TO DESORB THE ABSORBED VAPOURS, C. A PARTITION COLUMN CONNECTABLE TO THE OUTLET OF THE PASSTAGE FOR SEPARATING THE DESORBED VAPOURS, D. A DETECTOR CONNECTED TO THE PARTITION COLUMN FOR DETECTING THE SPECIFIC VAPOUR AMONG THE SEPARATED VAPOURS, E. A CARRIER GAS SOURCE CONNECTABLE TO THE INLET OF THE PASSAGE TO PROVIDE A FLOW OF A CARRIER GAS SO THAT THE CARRIER GAS PASSES THE DESORBED VAPOURS TO THE PARTITION COLUMN FOR SEPARATION AND THE SEPARATED VAPOURS TO THE DETECTOR FOR DETECTION OF THE SPECIFIC VAPOUR, F. SAID COLLECTOR ASSEMBLY BEING MOVABLE BETWEEN A SAMPLING POSITION WHERE THE PASSAGE IS COMMUNICATED WITH THE ATMOSPHERE WHILE DISCONNECTED TO THE PARTITION COLUMN AND THE CARRIER GAS SOURCE, AND AN ANALYZING POSITION WHERE THE PASSAGE IS CONNECTED TO THE PARTITION COLUMN AND THE CARRIER GAS SOURCE WHILE DISCONNECTED TO THE ATMOSPHERE, AND G. MEANS TO DRAW THE ATMOSPHERE SAMPLE OVER THE ABSORBANT WHEN THE COLLECTOR ASSEMBLY IS IN THE SAMPLING POSITION.
Claim 3
Dependent Claim
22 words
An apparatus as claimed in claim 1 wherein means are provided for controlling the temperature of the partition column and the detector.
Claim 4
Dependent Claim
53 words
An apparatus as claimed in claim 1 wherein the means to draw the atmospheric sample includes a pump for drawing the sample through the passage filled with the adsorbant and a control circuit for automatically shutting off the pump when the collector assembly is moved from the sampling position to the analyzing position.
Claim 5
Dependent Claim
67 words
An apparatus as claimed in claim 1 wherein the heating means includes a collector heating circuit designed to be automatically turned on when the collector assembly is moved from the sampling posiTion to the analyzing position and programmed to rapidly raise the temperature of the adsorbant to a predetermined level, and maintain it at that level for a predetermined short period of time before automatically shutting down.
Claim 6
Dependent Claim
16 words
An apparatus as claimed in claim 1 wherein the adsorbant is gold wire or nickel wire.
Claim 7
Dependent Claim
23 words
An apparatus as claimed in claim 1 wherein the carrier gas is helium, argon or argon containing about 5% by volume of methane.
Claim 8
Dependent Claim
23 words
An apparatus as claimed in claim 1 which includes means for cooling the adsorbant to a temperature below that of the atmospheric sample.
Claim 9
Dependent Claim
56 words
An apparatus as claimed in claim 1 wherein said collector assembly has an additional passage arranged to communicate with the carrier gas source and the partition column for flow of the carrier gas therethrough when the assembly is in the sampling position and to be disconnected from them when the assembly is in the analyzing position.
Claim 10
Dependent Claim
36 words
An apparatus as claimed in claim 8, wherein the heating means is electrically controlled to be automatically turned on and off to heat the adsorbant at a predetermined temperature for a predetermined short period of time.
Claim 11
Dependent Claim
35 words
An apparatus as claimed in claim 9 wherein the heating means includes a collector heating circuit adapted to be turned on when the collector assembly is moved from the sampling position to the analyzing position.
Claim 12
Dependent Claim
31 words
An apparatus as claimed in claim 10 wherein the collector heating circuit is associated also with the detector so that it be turned on when the detector detects the specific vapour.
Claim 13
Dependent Claim
94 words
An apparatus as claimed in claim 11 wherein the detector comprises a chamber having an inlet and an outlet for flow of the separated vapours therethrough from the inlet to the outlet, means to provide free electrons in the chamber, a cathode and an anode in the chamber and means to monitor the current flowing between the electrodes, the monitoring means including timing circuits providing internal timing for indication of the time at which the specific vapor is expected to pass through the chamber and for control of the collector heating and cooling circuit.
Claim 14
Dependent Claim
33 words
An apparatus as claimed in claim 12 wherein the partition column and the detector chamber are enclosed by an oven electrically controlled to maintain the column and the chamber at a predetermined temperature.
Claim 15
Dependent Claim
64 words
An apparatus as claimed in claim 1 wherein the detector comprises a chamber having an inlet and an outlet for flow of the separated vapours therethrough, means to provide free electrons in the chamber, and a cathode and an anode in the chamber for connection to means to apply a DC voltage to the electrodes and to monitor the current flowing between the electrodes.
Claim 16
Dependent Claim
23 words
An apparatus as claimed in claim 3 wherein the means to provide free electron is titanium tritide or Ni63 coated on the cathode.
Claim 17
Dependent Claim
36 words
An apparatus as claimed in claim 14 wherin the means to monitor the current includes timing circuits providing interval timing for indication of the time at which the specific vapour is expected to reach the chamber.
Claim 18
Dependent Claim
70 words
An apparatus according to claim 3 wherein said means to monitor the current flow between the electrodes includes a current to voltage converter amplifier having an input connected to said detector; a buffer amplifier having an input connected to said converter amplifier and a first differentiator circuit connected to said buffer amplifier to thereby produce an output signal corresponding to the first derivative of the current flow between the electrodes.
Claim 19
Dependent Claim
24 words
An apparatus according to claim 17 wherein said input to said converter amplifier is connected to said detector via an RC low pass filter.
Claim 20
Dependent Claim
17 words
An apparatus according to claim 18 wherein said converter amplifier and said buffer amplifier are operational amplifiers.
Claim 21
Dependent Claim
24 words
An apparatus according to claim 19 wherein said first differentiator circuit is comprised of the series connection of a capacitor and an operational amplifier.
Claim 22
Dependent Claim
47 words
An apparatus accOrding to claim 20 wherein said means to monitor further includes a second buffer and a second differentiator circuit respectively connected in series with said first differentiator circuit to thereby produce an output signal corresponding to the second derivative of the current flow between electrodes.
Claim 23
Dependent Claim
20 words
An apparatus according to claim 21 wherein said differentiator circuit consists of a series connected capacitor and an operational amplifier.
Claim 24
Dependent Claim
15 words
An apparatus according to claim 22 wherein said second buffer amplifier is an operational amplifier.
Claim 25
Dependent Claim
74 words
An apparatus according to claim 23, wherein said means to monitor further includes a threshold detector comprising an operational amplifier, said operational amplifier having a first input connected to said second differentiator and a second input connected to a reference voltage, said threshold detector having an output which is a digital signal indicative of the presence of a voltage level at the output of said second differentiator which is higher than said reference level.
Claim 26
Dependent Claim
46 words
An apparatus according to claim 24, wherein at least one capacitor is connected in parallel with said converter amplifier, said buffer amplifier, said first differentiator, said second buffer amplifier and said second differentiator so as to limit the high frequency response of said means for monitoring.
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) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |