US3817629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tubular sample cell having radially extending flanges at the ends of the cell for flameless atomic absorption
Assignee: Individual
•
Filing: 1973-04-20
•
Granted: 1974-06-18
•
Expires: 1993-04-20
Abstract
Abstract This is a tubular cell for atomizing samples in flameless atomic absorption spectroscopy of the type in which electric current is passed through the tubular cell to generate the heat for vaporizing the sample therein. The improvement comprises the use of radially extending flanges at the ends of the tube which are in both physical and electrical contact with the tube, and the electric current is supplied to the outer rim of the flanges. This construction reduces the tendency of the ends of the tube to be cooler than the center of the tube, since the flanges themselves generate heat and also their relative thinness inhibits large heat losses from the ends of the tube to the relatively massive electrodes which supply the electric current. The flanges may be shaped in various ways and may include cut-out portions to further increase current density therein and to reduce further their heat conductivity.
Inventors
- 👤 W Witte
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:49
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/71; G01N21/74
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
106 words
A tubular cell for vaporizing the sample for flameless atomic absorption by means of electric current heating, comprising: a hollow tube; generally disc-shaped flanges at and in physical contact with the ends of said tube so that said flanges extend from said ends in a substantially radial direction; contact means at the outer rim of said flanges for receiving electric current; said flanges having dimensions, particularly with respect to their thickness and thickness distribution, such that the amount of heat produced in them by such electric current is large compared to the heat lost by conduction so that cooling of the tube ends is substantially prevented.
Claim 2
Dependent Claim
106 words
A tubular cell for vaporizing the sample for flameless atomic absorption by means of electric current heating, comprising: a hollow tube; generally disc-shaped flanges at and in physical contact with the ends of said tube so that said flanges extend from said ends in a substantially radial direction; contact means at the outer rim of said flanges for receiving electric current; said flanges having dimensions, particularly with respect to their thickness and thickness distribution, such that the amount of heat produced in them by such electric current is large compared to the heat lost by conduction so that cooling of the tube ends is substantially prevented.
Claim 3
Dependent Claim
28 words
A tubular cell as claimed in claim 1, in which: said flanges are integral with said tube, so that said flanges and tube are a single integral unit.
Claim 4
Dependent Claim
33 words
A tubular cell as claimed in claim 1, in which: said flanges and said tube are mechanically separate components which contact each other at the tube ends at mutually mating contct faces (4).
Claim 5
Dependent Claim
18 words
A tubular cell as claimed in claim 3, in which: said contact faces (4) are conical in form.
Claim 6
Dependent Claim
17 words
A tube cell as claimed in claim 3 in which: said contact faces (4) are spherical surfaces.
Claim 7
Dependent Claim
23 words
A tubular cell as claimed in claim 1, in which: said contact means (3) at the outer rim of said flanges are conical.
Claim 8
Dependent Claim
24 words
A tubular cell as claimed in claim 1, in which: said contact means (3) at the outer rim of said flanges are spherical surfaces.
Claim 9
Dependent Claim
24 words
A tubular cell as claimed in claim 1, in which: said flanges have a constant thickness at least except for the outer rim thereof.
Claim 10
Dependent Claim
36 words
A tubular cell as claimed in claim 1, in which: said contact means comprise thickened portions of the outer rim portion of said flanges, so as to increase the contact area of said contact means (3).
Claim 11
Dependent Claim
24 words
A tubular cell as claimed in claim 1, in which: said flanges are planar in form and are arranged prependicularly to the tube axis.
Claim 12
Dependent Claim
32 words
A tubular cell as claimed in claim 1, in which: said flanges are inclined relative to the axis of the tube, so as to present a conical surface at said tube ends.
Claim 13
Dependent Claim
33 words
A tubular cell as claimed in claim 1, in which: said flanges extend from the tube ends initially towards the tube center so as to surround at least partially said sample tube (1).
Claim 14
Dependent Claim
36 words
A tubular cell as claimed in claim 1, in which: said sample tube (1) has at its ends short inwardly extending secondary flanges to increase the quantity of sample which may be held within said tube.
Claim 15
Dependent Claim
22 words
A tubular cell as claimed in claim 1, in which: said tube (1) and said flanges (2) are both made of graphite.
Claim 16
Dependent Claim
19 words
A tubular cell as claimed in claim 1, in which: said tube (1) has a cross-bore for sample introduction.
Claim 17
Dependent Claim
33 words
A tubular cell as claimed in claim 1, in which: a housing substantially surrounds said tube (1) and said flanges (2), so that the tubular cell is operated in a protective gas volume.
Claim 18
Dependent Claim
27 words
A tubular cell as claimed in claim 16, further comprising: means for introducing into said housing a forced protective gas flow which is passed through said tube.
Claim 19
Dependent Claim
24 words
A tubular cell as claimed in claim 1, in which: means are provided for closing off said tube ends by protective gas flow curtains.
Claim 20
Dependent Claim
24 words
A tubular cell as claimed in claim 1, in which: said flanges are cut away at their rims so as to provide recesses (30).
Claim 21
Dependent Claim
26 words
A tubular cell as claimed in claim 1, in which: said flanges are perforated at a small plurality of positions so as to provide apertures (32).
Claim 22
Dependent Claim
27 words
A tubular cell as claimed in claim 1, in which: said flanges are perforated by a plurality of circular shape apertures so as to provide bores (34).
Claim 23
Dependent Claim
43 words
A tubular cell as claimed in claim 1, in which: said flanges are relieved in some symmetrical manner so as to provide some type of apertures; and said two flanges are rotated with respect to each other so as to misalign said apertures.
Claim 24
Dependent Claim
21 words
A tubular cell as claimed in claim 1, in which: said flanges contain a plurality of small holes in sieve-like manner.
Claim 25
Dependent Claim
43 words
A tubular cell as claimed in claim 23, in which: at least one of the size and respective distance between said holes varies in a radial direction along each flange in order to obtain a favorable electric current density distribution across said flanges.
References Cited (Backward Citations)
US3671129A
Cited
US3702219A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |