# US 5,702,671 A · Gas chromatography transfer line

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- Number: US 5,702,671 A
- Document ID: US5702671A
- Status: Granted
- Kind: A
- Application number: 08/664,310
- Filed: 1996-06-11
- Granted: 1997-12-30
- Earliest claimed: 1995-06-12
- Inventors: Eberhard Gerstel
- Web page: https://patentgrep.com/patent/US5702671A

## CPC

- G01N 30/30: of temperature
- G01N 30/16: Injection (G01N30/24 takes precedence)
- G01N 2030/025: {Gas chromatography}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

The invention relates to a gas chromatography transfer line, having a glass tube (12), a steel tube (13) enclosing this glass tube and a heating coil (17) enclosing the steel tube, in which a tube (15) made of a material with high thermal conductivity is arranged between the steel tube (13) and the heating coil (17), the tube (15) being provided with a series of bores (16) in the axial and in the circumferential direction and being soldered to the heating coil (17) and to the steel tube (13), the solder (20) filling the bores (16) and intermediate spaces between the steel tube (13) and the tube (15).

## Claims

### Claim 1

A gas chromatography transfer line with an entry end and an exit end, comprising:
a first tube constructed of glass;
a second tube constructed of steel enclosing said first tube;
a heating coil enclosing said second tube;
a third tube constructed of a material with a thermal conductivity higher than that of the second tube;
said third tube having an axial and a circumferential direction and
being arranged between said second tube and said heating coil so as to provide interstices between said second tube and said third tube,
the third tube being provided with a series of bores spaced apart in said axial and in said circumferential direction and
the third tube being soldered by a solder to said heating coil and to said second tube;
wherein said solder fills said bores and said interstices between said second tube and said third tube.

### Claim 2 (depends on 1)

The transfer line of claim 1, wherein said third tube is made of copper, brass, gold or silver or an alloy thereof.

### Claim 3 (depends on 1)

The transfer line of claim 1, wherein the solder is a copper or silver solder.

### Claim 4 (depends on 1)

The transfer line of claim 1, wherein said heating coil is wound more narrowly adjacent to said entry and exit ends than therebetween.

### Claim 5 (depends on 1)

The transfer line of claim 1, wherein adjacent to said entry end said second tube protrudes from said third tube and from said heating coil and has a region with reduced wall thickness.

### Claim 6 (depends on 5)

The transfer line of claim 5, wherein said region is protected against damages by protecting means.

### Claim 7 (depends on 6)

The transfer line of claim 6, wherein said protecting means comprises a support plate.

### Claim 8 (depends on 7)

The transfer line of claim 7, wherein a sampling head for applying a sample to the transfer line is provided, said sampling head being fastened on a support means, said support plate of said protecting means being fastened to said support means.

### Claim 9 (depends on 1)

The transfer line of claim 1, wherein an outer protective tube is provided enclosing said heating coil.

### Claim 10 (depends on 1)

The transfer line of claim 1, wherein a metallic adaptor means is provided at said exit end.