Photoionization detector lamp and its method of manufacture

Patent metadata

Field	Value
Publication number	US-12405246-B2
Application number	US-202318317180-A
Country	US
Kind code	B2
Filing date	May 15, 2023
Priority date	Jun 1, 2022
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

Embodiments are provided for ultraviolet lamps for use in photoionization detectors and methods of manufacturing same. An example method of manufacturing an ultraviolet lamp includes providing a glass tube, the glass tube defining a first end; applying a mixed powder coating composition onto an edge surface of the first end of the glass tube, the mixed powder coating composition comprising indium powder and glass powder; applying a glass powder coating composition over the mixed powder coating composition; attaching a crystal window to the edge surface of the first end of the glass tube; and heating the glass tube and the crystal window to seal the crystal window to the glass tube.

First claim

What is claimed is:

1. A method of manufacturing a vacuum ultraviolet lamp, the method comprising:
providing a glass tube, the glass tube defining a first end;
applying a mixed powder coating composition onto an edge surface of the first end of the glass tube, the mixed powder coating composition comprising indium powder and glass powder;
applying a glass powder coating composition over the mixed powder coating composition;
attaching a crystal window to the edge surface of the first end of the glass tube; and
heating the glass tube and the crystal window to seal the crystal window to the glass tube.

2. The method of claim 1 , wherein the crystal window and the glass tube have different coefficients of thermal expansion (CTE).

3. The method of claim 2 , wherein the crystal window comprises lithium fluoride.

4. The method of claim 1 , wherein heating the glass tube and the crystal window comprises heating the glass tube and the crystal window in a heating chamber above about 400° C.

5. The method of claim 4 , wherein heating the glass tube and the crystal window comprises heating the glass tube and the crystal window for at least 30 minutes.

6. The method of claim 1 , further comprising applying a coating of glue at an external interface of the glass tube and the crystal window.

7. The method of claim 6 , wherein the glue is UV glue.

8. The method of claim 1 , wherein the glass tube defines a second end opposite the first end, the method further comprising:
attaching a vacuum system to the second end of the glass tube;
filling the glass tube with a low pressure gas; and
melting the second end of the glass tube such that the low pressure gas is sealed within the glass tube.

9. A vacuum ultraviolet lamp comprising:
a glass tube, the glass tube defining a first end;
a crystal window sealed to the first end of the glass tube, wherein sealing the crystal window to the first end of the glass tube comprises:
applying a mixed powder coating composition onto an edge surface of the first end of the glass tube, the mixed powder coating composition comprising indium powder and glass powder;
applying a glass powder coating composition over the mixed powder coating composition;
attaching the crystal window to the edge surface of the first end of the glass tube; and
heating the glass tube and the crystal window to seal the crystal window to the glass tube.

10. The vacuum ultraviolet lamp of claim 9 , wherein the crystal window and the glass tube have different coefficients of thermal expansion (CTE).

11. The vacuum ultraviolet lamp of claim 10 , wherein the crystal window comprises lithium fluoride.

12. The vacuum ultraviolet lamp of claim 9 , wherein heating the glass tube and the crystal window comprises heating the glass tube and the crystal window in a heating chamber above about 400° C.

13. The vacuum ultraviolet lamp of claim 12 , wherein heating the glass tube and the crystal window comprises heating the glass tube and the crystal window for at least 30 minutes.

14. The vacuum ultraviolet lamp of claim 9 , further comprising at least one fill gas sealed within the glass tube and crystal window.

15. A photoionization detector comprising:
two electrodes; and
a vacuum ultraviolet lamp comprising:
a glass tube, the glass tube defining a first end;
a crystal window sealed to the first end of the glass tube, wherein sealing the crystal window to the first end of the glass tube comprises:
applying a mixed powder coating composition onto an edge surface of the first end of the glass tube, the mixed powder coating composition comprising indium powder and glass powder;
applying a glass powder coating composition over the mixed powder coating composition;
attaching the crystal window to the edge surface of the first end of the glass tube; and
heating the glass tube and the crystal window to seal the crystal window to the glass tube.

16. The photoionization detector of claim 15 , wherein the crystal window and the glass tube of the vacuum ultraviolet lamp have different coefficients of thermal expansion (CTE).

17. The photoionization detector of claim 16 , wherein the crystal window of the vacuum ultraviolet lamp comprises lithium fluoride.

18. The photoionization detector of claim 15 , wherein the vacuum ultraviolet lamp is filled with a low pressure fill gas.

19. The photoionization detector of claim 15 , wherein the two electrodes are disposed proximate to the crystal window of the vacuum ultraviolet lamp.

20. The photoionization detector of claim 15 , wherein the photoionization detector is exposed to a sample gaseous substance and the vacuum ultraviolet lamp emits photon energy to ionize a target analyte in the sample gaseous substance.

Assignees

• Honeywell Int Inc

Inventors

• Huang Chuang
• Wang Qingling

Classifications

• G01N2030/642

  photoionisation detectors · CPC title

• G01N30/64

  Electrical detectors · CPC title

• H01J61/302

  characterised by the material of the vessel · CPC title

• H01J9/266

  specially adapted for gas-discharge lamps · CPC title

• H01J61/361

  Seals between parts of vessel · CPC title