Seal for gas chromatography

• US 20070089603A1
• Filed: 10/21/2005
• Published: 04/26/2007
• Est. Priority Date: 10/21/2005
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Norman, Wesley, Klee, Matthew, Emmons, William
• Granted Patent: US 7,384,457 B2
• Time in Patent Office: Days
• US Class Current: 95/82
• CPC Class Codes: G01N 2030/185 specially adapted to seal the inlet
• CPC Class Codes: G01N 30/18 using a septum or microsyringe

Abstract

A seal forming a fluid tight connection between a gas chromatography column and a sample inlet assembly is disclosed. The seal is formed by a metal injection molding process. The seal has a first surface adapted for sealing with the sample inlet assembly and a second surface adapted for sealing with the column. The seal has an aperture extending between the first and second surfaces. A method of sealing a connection between a gas chromatography sample inlet assembly and a gas chromatography column is also disclosed. The method includes providing a seal as described above, compressing the first surface of the seal against an end of the inlet assembly, positioning the column in fluid communication with the aperture, and engaging the column with the second surface.

Claims

1. A seal forming a fluid tight connection between a gas chromatography column and a sample inlet assembly, said sample inlet assembly comprising a conduit, said seal comprising:

a plate formed from metal powder using a metal injection molding process, said plate having a first surface on one side adapted for sealing engagement with said conduit, said plate having a second surface on an opposite side adapted for sealing engagement with said column; and

an aperture extending through said plate between said first and second surfaces, said aperture positioned to provide fluid communication between said column and said sample inlet assembly.

2. A seal according to claim 1, wherein said aperture is sized to receive said column.

3. A seal according to claim 1, wherein said column includes a ferrule attached thereto, said second surface having a shape adapted for sealing engagement with said ferrule.

4. A seal according to claim 1, wherein said metal powder comprises stainless steel.

5. A seal according to claim 1, wherein said plate is coated with a material selected from the group consisting of silica, nickel, nickel alloy, stainless steel alloy, gold and tantalum.

6. A seal according to claim 1, wherein said first surface has a surface finish having no irregularities larger than 0.4 microns deep.

7. A seal according to claim 1, wherein said first surface has a hardness between 60 and 80 on the Rockwell B scale.

8. A seal according to claim 1, wherein said conduit comprises an outer shell surrounding a liner, said liner having a bore therethrough, a space being positioned between said shell and said liner, said seal further comprising a depression positioned within said first surface, said depression extending from said bore of said liner to said space between said liner and said outer shell and providing fluid communication therebetween.

9. A seal according to claim 8, wherein said depression comprises a groove.

10. A seal according to claim 1, wherein said conduit comprises an outer shell surrounding a liner, said liner having a bore therethrough, a first space being positioned between said shell and said liner, said seal further comprising a projection extending outwardly from said first surface, said projection engaging an end of said liner and defining a second space between said liner and said first surface, said second space providing fluid communication between said bore and said first space.

11. A seal according to claim 10, wherein said projection comprises a rib.

12. A gas chromatography sample inlet assembly connectable to a gas chromatography column, said inlet assembly comprising:

a shell having a shell bore;

a liner having a liner bore, said liner being positioned within said shell bore, a first space being positioned between said liner and said shell;

an injector port in fluid communication with said liner bore;

a vent port in fluid communication with said first space between said liner and said shell;

a plate formed from metal powder using a metal injection molding process, said plate having a first surface on one side adapted for sealing engagement with an end of said shell, said plate having a second surface on an opposite side adapted for sealing engagement with an end of said column;

a second space positioned between said liner and said plate, said second space providing fluid communication between said liner bore and said first space; and

an aperture extending through said plate between said first and second surfaces, said aperture sized to receive said end of said column therein and provide fluid communication between said column and said liner bore.

13. An inlet assembly according to claim 12, wherein said column includes a ferrule attached thereto, said second surface having a shape adapted for sealing engagement with said ferrule.

14. An inlet assembly according to claim 12, wherein said metal powder comprises stainless steel.

15. An inlet assembly according to claim 12, wherein said plate is coated with a material selected from the group consisting of silica, nickel, nickel alloy, stainless steel alloy, gold and tantalum.

16. An inlet assembly according to claim 12, wherein said first surface has a surface finish having no irregularities larger than 0.4 microns deep.

17. An inlet assembly according to claim 12, wherein said first surface has a hardness between 60 and 80 on the Rockwell B scale.

18. An inlet assembly according to claim 12, wherein said seal comprises a depression positioned within said first surface, said depression extending from said liner bore to said first space and providing fluid communication therebetween.

19. An inlet assembly according to claim 18, wherein said depression comprises a groove.

20. An inlet assembly according to claim 12, wherein said seal comprises a projection extending outwardly from said first surface, said projection engaging an end of said liner and defining a second space between said liner and said first surface, said second space providing fluid communication between said liner bore and said first space.

21. An inlet assembly according to claim 20, wherein said projection comprises a rib.

22. A method of sealing a connection between a gas chromatography sample inlet assembly and a gas chromatography column, said inlet assembly having a conduit, said method comprising:

providing a seal made from metal powder using a metal injection molding process, said seal comprising a plate having a first surface on one side adapted for sealing engagement with an end of said conduit and a second surface on an opposite side adapted for sealing engagement with said column, said plate having an aperture extending therethrough between said first and second surfaces providing fluid communication between said conduit and said column;

compressing said first surface of said seal against said end of said conduit;

positioning said column in fluid communication with said aperture;

engaging said column with said second surface.