US3926209A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and inlet control system for controlling a gas flow sample to an evacuated chamber
Assignee: University of Colorado Boulder
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Filing: 1974-09-23
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Granted: 1975-12-16
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Expires: 1994-09-23
Abstract
Abstract A method and inlet control system for controlling a gas flow sample to an evacuated chamber such as found in a mass spectrometer, is disclosed. The system utilizes a short inlet passage having an effective opening determined by a tapered diamond or steel tip needle adjacent to the inlet passage. The needle is positionally adjusted with respect to the inlet passage by being mounted on a piezoelectric crystal which is flexed by coupling thereto an electric potential derived by sensing the ions at the ionization chamber of a mass spectrometer, for example, and developing therefrom an electric signal indicative of the total pressure within the ionization chamber. The signal coupled to the piezoelectric crystal is preferably a pulse-width modulated signal with the needle maintaining the inlet passage closed except during the time that the piezoelectric crystal is flexed due to a received pulse. A vacuum pump, and a quadrupole filter, both of which are relatively small, are also disclosed, so that a mass spectrometer system, for example, is sufficiently compact so as to be useful, in conjunction with a respiratory valve, for the analysis of respiratory gases. The method for controlling a gas sample flow to a mass spectrometer, for example, comprises providing an inlet for a gas sample into the ionization chamber of the mass spectrometer, monitoring the pressure within the ionization chamber and developing an electrical signal indicative thereof, and utilizing the developed electrical signal to control the flow of gas sample through the inlet to maintain a substantially constant pressure within the ionization chamber.
Inventors
- 👤 Ingvar E Sodal
- 👤 Lars Hoivik
- 👤 Alexander J Micco
- 👤 John V Weil
- 👤 Norman W Baer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:33
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/02; H01J49/04; H01J49/0495; H01J49/10; H01J49/14; H01J49/147; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7758; Y10T137/7761
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
A servo-controlled inlet system for an evacuated chamber, said system comprising: an inlet passage opening into the interior of an evacuated chamber and through which gas may be introduced into said chamber; valve means at said inlet passage for controlling the effective opening through which gas may be introduced into said passage; valve positioning means connected with said valve means to position the same; sensing means for sensing the pressure within said evacuated chamber and developing an electrical signal indicative thereof; and signal processing means including control amplifier means for receiving said signal from said sensing means and responsive thereto producing a pulsewidth modulated control signal that is coupled to said valve positioning means to control the same whereby said valve means is automatically adjusted in position dependent upon sensed pressure.
Claim 2
Dependent Claim
131 words
A servo-controlled inlet system for an evacuated chamber, said system comprising: an inlet passage opening into the interior of an evacuated chamber and through which gas may be introduced into said chamber; valve means at said inlet passage for controlling the effective opening through which gas may be introduced into said passage; valve positioning means connected with said valve means to position the same; sensing means for sensing the pressure within said evacuated chamber and developing an electrical signal indicative thereof; and signal processing means including control amplifier means for receiving said signal from said sensing means and responsive thereto producing a pulsewidth modulated control signal that is coupled to said valve positioning means to control the same whereby said valve means is automatically adjusted in position dependent upon sensed pressure.
Claim 3
Dependent Claim
32 words
The system of claim 1 wherein said valve positioning meanS includes a piezoelectric crystal connected with said valve means whereby said valve means is positionally controlled by the flexing of said crystal.
Claim 4
Dependent Claim
143 words
An inlet control system for an evacuated chamber, said system comprising: an inlet passage opening into the interior of said evacuated chamber to introduce gas samples therethrough; valve means including a needle valve one end of which is tapered and positionally adjustable adjacent to said inlet passage to control the effective opening through said passage; a piezoelectric crystal; means connecting the center portion of said piezoelectric crystal with said needle valve so that the positioning of said valve is controlled by the amount of flexing of said crystal; sensing means within the evacuated chamber for developing an electrical signal that is indicative of the pressure within said evacuated chamber; and signal processing means connected to receive said electrical signal from said sensing means and producing an output that is coupled to said piezoelectric crystal to control the amount of flexing of said crystal.
Claim 5
Dependent Claim
143 words
An inlet control system for an evacuated chamber, said system comprising: an inlet passage opening into the interior of said evacuated chamber to introduce gas samples therethrough; valve means including a needle valve one end of which is tapered and positionally adjustable adjacent to said inlet passage to control the effective opening through said passage; a piezoelectric crystal; means connecting the center portion of said piezoelectric crystal with said needle valve so that the positioning of said valve is controlled by the amount of flexing of said crystal; sensing means within the evacuated chamber for developing an electrical signal that is indicative of the pressure within said evacuated chamber; and signal processing means connected to receive said electrical signal from said sensing means and producing an output that is coupled to said piezoelectric crystal to control the amount of flexing of said crystal.
Claim 6
Dependent Claim
53 words
The system of claim 3 wherein said piezoelectric crystal is a bimorph crystal that maintains said needle valve in a position such that said inlet passage is closed except when a predetermined signal is received from said signal processing means to flex said crystal in a manner so as to open said valve.
Claim 7
Dependent Claim
43 words
The system of claim 4 wherein said signal processing means produces a pulse-width modulated signal that is coupled to said piezoelectric crystal so that said crystal maintains said inlet passage closed except during the occurrence of each pulse of said pulse-width modulated signal.
Claim 8
Dependent Claim
103 words
An evacuated chamber system comprising: an evacuatable chambers, gas sampling means including an inlet passage opening into said evacuatable chamber to conduct gas samples thereto; valve means for determining the effective opening through said inlet passage; sensing means for sensing the pressure within said evacuatable chamber and developing an electrical signal indicative thereof; and control means including a bimorph piezoelectric crystal the center portion of which is connected with said valve means, said control means receiving said signal from said sensing means and responsive thereto controlling the flexing of said piezoelectric crystal to thereby positionally control said valve means dependent upon sensed pressure.
Claim 9
Dependent Claim
103 words
An evacuated chamber system comprising: an evacuatable chambers, gas sampling means including an inlet passage opening into said evacuatable chamber to conduct gas samples thereto; valve means for determining the effective opening through said inlet passage; sensing means for sensing the pressure within said evacuatable chamber and developing an electrical signal indicative thereof; and control means including a bimorph piezoelectric crystal the center portion of which is connected with said valve means, said control means receiving said signal from said sensing means and responsive thereto controlling the flexing of said piezoelectric crystal to thereby positionally control said valve means dependent upon sensed pressure.
Claim 10
Dependent Claim
147 words
An evacuated chamber system comprising: an evacuatable chamber; a vacuum pump connected with said evacuatable chamber; an inlet passage opening into said evacuatable chamber and through which gas may be introduced into said evacuatable chamber; valve means including a needle valve one end of which is tapered and positionally adjustable adjacent to said inlet passage to control the effective opening thereof; a piezoelectric crystal; means connecting the center portion of said piezoelectric crystal with said needle valve so that positioning of said valve is controlled by the amount of flexing of said crystal; sensing means within said evacuatable chamber of sensing the pressure within said chamber and developing an electrical signal indicative thereof; and signal processing means connected with said sensing means and with said piezoelectric crystal whereby a signal developed by said sensing means is utilized to control the amount of flexing of said piezoelectric crystal.
Claim 11
Dependent Claim
147 words
An evacuated chamber system comprising: an evacuatable chamber; a vacuum pump connected with said evacuatable chamber; an inlet passage opening into said evacuatable chamber and through which gas may be introduced into said evacuatable chamber; valve means including a needle valve one end of which is tapered and positionally adjustable adjacent to said inlet passage to control the effective opening thereof; a piezoelectric crystal; means connecting the center portion of said piezoelectric crystal with said needle valve so that positioning of said valve is controlled by the amount of flexing of said crystal; sensing means within said evacuatable chamber of sensing the pressure within said chamber and developing an electrical signal indicative thereof; and signal processing means connected with said sensing means and with said piezoelectric crystal whereby a signal developed by said sensing means is utilized to control the amount of flexing of said piezoelectric crystal.
Claim 12
Dependent Claim
25 words
The system of claim 7 wherein said elements are relatively small so that said system is sufficiently compact to enable close useage and enhance stability.
References Cited (Backward Citations)
US3465732A
Cited
US3747634A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-15 | 1979-06-16 | 1979-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-15 | 1983-06-16 | 1983-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-15 | 1987-06-16 | 1987-12-16 | $7700.00 | Window Closed / Lapsed |