US3893769A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Graphite tube furnace
Assignee: International Standard Electric Corp
•
Filing: 1974-05-30
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Granted: 1975-07-08
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Expires: 1994-05-30
Abstract
Abstract Apparatus for vaporizing samples for analysis by the use of a spectrophotometer. A carbon tube is electrically heated to vaporize the sample. The tube is conveniently held by electrode spring finger contacts. A transparent envelope encompasses the tube and has an inlet arrangement that facilitates flushing with argon.
Inventors
- 👤 John Frederick Woolley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:58
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/71; G01N21/74; F; F27; F27B; F27B17/00; F27B17/02
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
120 words
A graphite tube furnace for atomic absorption spectroscopy, said furnace comprising: a support; a pair of electrically conductive heat sinks fixed to said support; a hollow ferrule threaded into each of said heat sinks; a hollow tapered bushing mounted inside each respective ferrule; a graphite tube having both ends open and having the said ends thereof mounted inside respective ferrules, each of said bushings being slotted and having spring fingers clamping respective graphite tube ends, each heat sink having a tapered hole cooperating with the taper of respective bushings, said ferrules, bushings and graphite tube forming an assembly defining a hollow, unobstructed path extending completely therethrough through which light can pass in the direction of the axis of the tube.
Claim 2
Dependent Claim
120 words
A graphite tube furnace for atomic absorption spectroscopy, said furnace comprising: a support; a pair of electrically conductive heat sinks fixed to said support; a hollow ferrule threaded into each of said heat sinks; a hollow tapered bushing mounted inside each respective ferrule; a graphite tube having both ends open and having the said ends thereof mounted inside respective ferrules, each of said bushings being slotted and having spring fingers clamping respective graphite tube ends, each heat sink having a tapered hole cooperating with the taper of respective bushings, said ferrules, bushings and graphite tube forming an assembly defining a hollow, unobstructed path extending completely therethrough through which light can pass in the direction of the axis of the tube.
Claim 3
Dependent Claim
59 words
A graphite tube furnace as claimed in claim 1, wherein a tubular envelope is provided and mounted between said heat sinks around said graphite tube, said envelope being provided in its side wall with an inlet tube which is substantially tangential to said envelope, said envelope being provided with an outlet tube which is substantially radial of the envelope.
Claim 4
Dependent Claim
83 words
A graphite tube furnace as claimed in claim 2, wherein the inlet and outlet tubes have axes that lie in a common plane normal to the axis of said envelope. 4. A graphite tube furnace as claimed in claim 3, wherein the inlet and outlet tubes are located relative to each other in a manner such that the path of a gas entering said inlet tube is circumferential inside said envelope and extends around inside said envelope over approximately five-eighths of a circle.
Claim 5
Dependent Claim
16 words
A graphite tube furnace as claimed in claim 4, wherein said envelope is made of silica.
Claim 6
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 5, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 7
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 5, wherein said heat sinks have means to permit them to be water cooled.
Claim 8
Dependent Claim
16 words
A graphite tube furnace as claimed in claim 2, wherein said envelope is made of silica.
Claim 9
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 8, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 10
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 8, wherein said heat sinks have means to permit them to be water cooled.
Claim 11
Dependent Claim
16 words
A graphite tube furnace as claimed in claim 3, wherein said envelope is made of silica.
Claim 12
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 11, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 13
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 11, wherein said heat sinks have means to permit them to be water cooled.
Claim 14
Dependent Claim
17 words
A graphite tube furnace as claimed in claim 2, wherein said envelope is made of transparent glass.
Claim 15
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 14, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 16
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 14, wherein said heat sinks have means to permit them to be water cooled.
Claim 17
Dependent Claim
17 words
A graphite tube furnace as claimed in claim 3, wherein said envelope is made of transparent glass.
Claim 18
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 17, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 19
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 17, wherein said heat sinks have means to permit them to be water cooled.
Claim 20
Dependent Claim
17 words
A graphite tube furnace as claimed in claim 4, wherein said envelope is made of transparent glass.
Claim 21
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 20, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 22
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 20, wherein said heat sinks have means to permit them to be water cooled.
Claim 23
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 1, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 24
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 1, wherein said heat sinks have means to permit them to be water cooled.
Claim 25
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 2, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 26
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 2, wherein said heat sinks have means to permit them to be water cooled.
Claim 27
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 3, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 28
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 3, wherein said heat sinks have means to permit them to be water cooled.
Claim 29
Dependent Claim
21 words
A graphite tube furnace as claimed in claim 4, wherein said graphite tube contains a central region of reduced wall thickness.
Claim 30
Dependent Claim
22 words
A graphite tube furnace as claimed in claim 4, wherein said heat sinks have means to permit them to be water cooled.
References Cited (Backward Citations)
US3671129A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-07 | 1979-01-06 | 1979-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-07 | 1983-01-06 | 1983-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-07 | 1987-01-06 | 1987-07-08 | $7700.00 | Window Closed / Lapsed |