US3895231A
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: 1973-04-30
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Granted: 1975-07-15
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Expires: 1993-04-30
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
2026-11-03 13:11
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/02; H01J49/04; H01J49/0495; H01J49/10; H01J49/14; H01J49/147
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
127 words
A servo-controlled inlet system for a mass spectrometer, said system comprising: an inlet passage opening into the interior of said mass spectrometer and through which gas may be introduced into said mass spectrometer; valve means at said inlet passage for controlling the effective opening through which gas may be introduced into said passage; valve positioning means including a piezoelectric crystal connected with said valve means whereby said valve means is positionally controlled by the flexing of said crystal; sensing means for sensing the pressure within said spectrometer and developing an electrical signal indicative thereof; and signal processing means for receiving said signal from said sensing means and responsive thereto controlling said valve poSitioning means whereby said valve means is automatically adjusted in position dependent upon sensed pressure.
Claim 2
Dependent Claim
127 words
A servo-controlled inlet system for a mass spectrometer, said system comprising: an inlet passage opening into the interior of said mass spectrometer and through which gas may be introduced into said mass spectrometer; valve means at said inlet passage for controlling the effective opening through which gas may be introduced into said passage; valve positioning means including a piezoelectric crystal connected with said valve means whereby said valve means is positionally controlled by the flexing of said crystal; sensing means for sensing the pressure within said spectrometer and developing an electrical signal indicative thereof; and signal processing means for receiving said signal from said sensing means and responsive thereto controlling said valve poSitioning means whereby said valve means is automatically adjusted in position dependent upon sensed pressure.
Claim 3
Dependent Claim
40 words
The system of claim 1 wherein said inlet passage opens into the ionization chamber of said mass spectrometer, and wherein said sensing means includes an ion sensitive plate for intercepting a portion of the ions developed within said ionization chamber.
Claim 4
Dependent Claim
33 words
The system of claim 1 wherein said signal processing means includes control amplifier means for receiving the output from said sensing means and developing a signal suitable for controlling said valve positioning means.
Claim 5
Dependent Claim
28 words
The system of claim 3 wherein said control amplifier means produces a pulse-width modulated control signal that is coupled to said valve positioning means to control the same.
Claim 6
Dependent Claim
155 words
A servo-controlled inlet system for a mass spectrometer said system comprising: an inlet passage opening into the ionization chamber of said mass spectrometer and through which gas may be introduced thereto; 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 and thereby control the amount of gas flow in said inlet passage; a piezoelectric crystal; means connecting said piezoelectric crystal with said needle valve so that the position of said valve is controlled by the amount of flexing of said crystal; sensing means within the spectrometer for developing an electric signal by ion sensing that is indicative of the pressure within said ionization 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 7
Dependent Claim
155 words
A servo-controlled inlet system for a mass spectrometer said system comprising: an inlet passage opening into the ionization chamber of said mass spectrometer and through which gas may be introduced thereto; 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 and thereby control the amount of gas flow in said inlet passage; a piezoelectric crystal; means connecting said piezoelectric crystal with said needle valve so that the position of said valve is controlled by the amount of flexing of said crystal; sensing means within the spectrometer for developing an electric signal by ion sensing that is indicative of the pressure within said ionization 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 8
Dependent Claim
48 words
The system of claim 5 wherein said piezoelectric crystal 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 9
Dependent Claim
42 words
The system of claim 6 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 10
Dependent Claim
119 words
A mass spectrometer system comprising: ion producing and handling means including an ionization chamber; gas sampling means including an inlet passage opening into said ionization chamber to conduct gas samples thereto, said gas sampling means including a respiratory valve one portion of which communicates with said inlet passage; valve means for determining the effective opening through said inlet passage; sensing means for sensing the pressure within said ionization chamber and developing an electrical signal indicative thereof; and control means including a piezoelectric crystal 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 11
Dependent Claim
119 words
A mass spectrometer system comprising: ion producing and handling means including an ionization chamber; gas sampling means including an inlet passage opening into said ionization chamber to conduct gas samples thereto, said gas sampling means including a respiratory valve one portion of which communicates with said inlet passage; valve means for determining the effective opening through said inlet passage; sensing means for sensing the pressure within said ionization chamber and developing an electrical signal indicative thereof; and control means including a piezoelectric crystal 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 12
Dependent Claim
173 words
A mass spectrometer system comprising: a respiratory valve; an ionization chamber; a vacuum pump connected with said ionization chamber; an inlet passage opening into said ionization chamber from said respiratory valve and through which gas may be introduced into said ionization 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 said piezoelectric crystal with said needle valve so that positioning of said valve is controlled by the amount of flexing of said crystal; focusing plates to focus ions emitted from said ionization chamber; a sensing plate adjacent to said focusing plates to receive a portion of ions emitted from said ionization chamber; a quadrupole filter through wHich said emitted ions are directed by said focusing plates; and signal processing means connected with said sensing plate and with said piezoelectric crystal whereby a signal developed by said sensing plate is utilized to control the amount of flexing of said piezoelectric crystal.
Claim 13
Dependent Claim
173 words
A mass spectrometer system comprising: a respiratory valve; an ionization chamber; a vacuum pump connected with said ionization chamber; an inlet passage opening into said ionization chamber from said respiratory valve and through which gas may be introduced into said ionization 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 said piezoelectric crystal with said needle valve so that positioning of said valve is controlled by the amount of flexing of said crystal; focusing plates to focus ions emitted from said ionization chamber; a sensing plate adjacent to said focusing plates to receive a portion of ions emitted from said ionization chamber; a quadrupole filter through wHich said emitted ions are directed by said focusing plates; and signal processing means connected with said sensing plate and with said piezoelectric crystal whereby a signal developed by said sensing plate is utilized to control the amount of flexing of said piezoelectric crystal.
Claim 14
Dependent Claim
26 words
The system of claim 9 wherein said elements are relatively small so that said system is sufficiently compact to enable close usage and enhance system stability.
Claim 15
Independent Claim
100 words
A method for controlling gas sample flow to a mass spectrometer, said method comprising: providing an inlet for gas sample into the ionization chamber of a mass spectrometer, said inlet having an opening the size of which is dependent upon the amount of flexing of a piezoelectric crystal; monitoring the pressure within the ionization chamber by ion sensing and developing an electrical signal indicative thereof; and utilizing the developed electrical signal to control the flexing of said piezoelectric crystal to thereby control the flow of gas sample through the inlet to maintain a substantially constant pressure within the ionization chamber.
Claim 16
Independent Claim
100 words
A method for controlling gas sample flow to a mass spectrometer, said method comprising: providing an inlet for gas sample into the ionization chamber of a mass spectrometer, said inlet having an opening the size of which is dependent upon the amount of flexing of a piezoelectric crystal; monitoring the pressure within the ionization chamber by ion sensing and developing an electrical signal indicative thereof; and utilizing the developed electrical signal to control the flexing of said piezoelectric crystal to thereby control the flow of gas sample through the inlet to maintain a substantially constant pressure within the ionization chamber.
Claim 17
Dependent Claim
35 words
The method of claim 11 further including providing a respiratory valve from which gas sample is taken through said inlet so that both inspired and expired gas samples may be tested by the mass spectrometer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |