US5095247A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plasma discharge apparatus with temperature sensing
Assignee: Shimadzu Corp
•
Filing: 1989-08-30
•
Granted: 1992-03-10
•
Expires: 2009-08-30
Abstract
Abstract A plasma discharge apparatus has a first electrode, a counter electrode, and a power source for supplying power to the first and counter electrodes for initiating and sustaining plasma discharge therebetween. An isolated heater is provided for heating only the first electrode. An isolated temperature sensor is provided for sensing the temperature of the first electrode, and a temperature controller is provided, responsive to the output of the temperature sensor, for controlling the heater to control the temperature of the first electrode.
Inventors
- 👤 Shigeki Hanamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:33
CPC Classifications
H; H05; H05H; H05H1/00; H05H1/24; G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/22; H05H1/48
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
99 words
A plasma discharge apparatus, comprising: a first electrode; a counter electrode; a power source for supplying power to said first and counter electrodes for initiating and sustaining a plasma discharge therebetween; isolated heating means for heating only said first electrode; isolated temperature sensing means for sensing only the temperature of said first electrode; and a temperature controlling means, responsive to an output of said isolated temperature sensing means, for controlling said isolated heating means to control the temperature of said first electrode, wherein electron emission from the first electrode is controlled by controlling the temperature of the first electrode.
Claim 2
Dependent Claim
99 words
A plasma discharge apparatus, comprising: a first electrode; a counter electrode; a power source for supplying power to said first and counter electrodes for initiating and sustaining a plasma discharge therebetween; isolated heating means for heating only said first electrode; isolated temperature sensing means for sensing only the temperature of said first electrode; and a temperature controlling means, responsive to an output of said isolated temperature sensing means, for controlling said isolated heating means to control the temperature of said first electrode, wherein electron emission from the first electrode is controlled by controlling the temperature of the first electrode.
Claim 3
Dependent Claim
18 words
The plasma discharge apparatus of claim 1, wherein said first electrode is integrated with said isolated heating means.
Claim 4
Dependent Claim
37 words
The plasma discharge apparatus of claim 1, further comprising a plasma chamber containing said first and counter electrodes, said plasma chamber having an inlet port and an exhaust port for allowing a sample gas to pass therethrough.
Claim 5
Dependent Claim
16 words
The plasma discharge apparatus of claim 1, wherein said isolated temperature sensing means is a thermocouple.
Claim 6
Dependent Claim
14 words
The plasma discharge apparatus of claim 4, wherein said thermocouple is a platinum-platinum/rhodium thermocouple.
Claim 7
Dependent Claim
20 words
The plasma discharge apparatus of claim 4, wherein said temperature controlling means includes a primary amplifier connected to said thermocouple.
Claim 8
Dependent Claim
53 words
The plasma discharge apparatus of claim 6, wherein said temperature controlling means also includes, a temperature setting circuit receiving an output from said primary amplifier, a power amplifier receiving outputs from said temperature setting circuit and said primary amplifier, and a motor driven by said power amplifier for controlling said isolated heating means.
Claim 9
Dependent Claim
26 words
The plasma discharge apparatus of claim 1, wherein said power source includes a step-up transformer for supplying a supply voltage to said first and counter electrodes.
Claim 10
Dependent Claim
16 words
The plasma discharge apparatus of claim 1, wherein said isolated heating means includes a step-down transformer.
Claim 11
Dependent Claim
22 words
The plasma discharge apparatus of claim 2, wherein said isolated heating means includes a step-down transformer connected directly to said first electrode.
Claim 12
Dependent Claim
31 words
The plasma discharge apparatus of claim 1, wherein said isolated electrodes, said power source and said isolated heating means are configured such that helium is usable as a plasma excitation gas.
Claim 13
Dependent Claim
27 words
The plasma discharge apparatus of claim 3, wherein said plasma chamber includes a quartz window to allow spectral emissions from the sample plasma to be transmitted therethrough.
Claim 14
Dependent Claim
23 words
The plasma discharge apparatus of claim 3, wherein said plasma chamber is configured such that the plasma discharge occurs at substantially atmospheric pressure.
Claim 15
Dependent Claim
40 words
The plasma discharge apparatus of claim 3, wherein said exhaust port of said plasma chamber has a size sufficiently small to maintain a flow of gas therefrom which will not allow leakage of atmospheric gas back into said plasma chamber.
Claim 16
Dependent Claim
32 words
The plasma discharge apparatus of claim 14, wherein said exhaust port is sufficiently small such that a velocity of gas exiting said exhaust port is maintained substantially at or above 5 meters/second.
References Cited (Backward Citations)
US4341947A
Cited
US4301391A
Cited
US4479075A
Cited
US4684848A
Cited
US4740730A
Cited
US4877999A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-10 | 1995-09-09 | 1996-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-10 | 1999-09-09 | 2000-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-10 | 2003-09-09 | 2004-03-10 | $7700.00 | Window Closed / Lapsed |