WO1996002320B1 - Hydrogen torch - Google Patents

Abstract

A hydrogen torch comprising concentric inner (1) and outer (3) fluid delivery tubes, wherein: a) the outer tube (3) comprises silica, and b) the inner tube (1) comprises silicon carbide.

Claims

AMENDED CLAIMS[received by the International Bureau on 2 October 1996 (02.10.96); original claims 1-87 replaced by amended claims 1-24 (5 pages)]

1. A hydrogen torch comprising inner and outer fluid delivery tubes, a third fluid delivery tube, a hydrogen source having a hydrogen supply line extending therefrom, and an oxygen source having an oxygen supply line extending therefrom, wherein: a) the outer tube comprises a first material and has an inlet in fluid connection with one of the supply lines, b) the inner tube comprises a second material and has a first end and a second end, and c) the third tube is in fluid connection with the first end of the inner tube and has an inlet in fluid connection with the remaining supply line.

2. The hydrogen torch of claim 1 wherein the third tube is silica.

3. The hydrogen torch of claim 1 wherein the first end of the inner tube has a ball shape.

4. The hydrogen torch of claim 1 wherein the fluid connection is accomplished by a reverse ball joint connection.

5. The hydrogen torch of claim 4 wherein the outer tube has a first and a second end, the first end of the outer tube forming a sealing connection with the first end of the inner tube, and the second end of the outer tube adapted

to form a fluid connection with a process tube.

6. The torch of claim 1 wherein the outer tube comprises

fused silica.

7. The torch of claim 1 wherein the inner tube comprises

silicon carbide.

8. The torch of claim 1 wherein the inner tube consists essentially of silicon carbide.

9. The torch of claim 1 wherein the outer tube is fused

silica and the inner tube comprises silicon carbide.

10. The hydrogen torch of claim 1 wherein the inner tube is a

drain cast silicon carbide ceramic tube having an outer

diameter of between 4 mm and 20 mm, a wall thickness of

between 0.75 mm and 3 mm, a room temperature flexural strength of at least 250 MPa, and a wall thickness variation of less than 0.2 mm/m.

11. A reverse ball joint connection comprising:

a) a first component comprising:

i) a first tube having a first end, and

ii) a first hollow hemispherical projection opening

outwardly from the first end, and

b) a second component comprising: i) a second tube having a first end, and

ii) a second hollow hemispherical projection opening

outwardly from the first end of the second tube,

said second tube having a larger diameter than and essentially

concentric with the first tube, the first tube being fitted

within the second tube such that the convex surface of the

first projection forms a seal with the concave surface of the

second projection.

12. The reverse ball joint connection of claim 11 wherein the

first and second components are made from different

materials.

13. The reverse ball joint connection of claim 11 wherein the

first component comprises silicon carbide.

14. The reverse ball joint connection of claim 11 wherein the second component comprises silica.

15. The reverse ball joint connection of claim 13 wherein the

first component consists essentially of siliconized

silicon carbide.

16. The reverse ball joint connection of claim 15 wherein the

second component consists essentially of silica.

17. The reverse ball joint connection of claim 11 wherein the

first component consists essentially of siliconized silicon

2 1 carbide and the second component consists essentially of

silica.

18. A drain cast silicon carbide ceramic tube having an outer

diameter of between 4 mm and 20 mm, a wall thickness of

between 0.75 mm and 3 mm, a wall thickness variation of less

than 0.2 mm/m, and a room temperature flexural strength of at

least 250 MPa.

19. The tube of claim 18 having a bimodal SiC grain

distribution comprising a fine fraction of between about 2

urn and about 3 urn and a coarse fraction of about 60 urn.

20. The tube of claims 18 wherein the silicon carbide consists

essentially of recrystallized silicon carbide.

21. A cast, unfired silicon carbide body having an average pore size of about 0.4 urn.

22. A process comprising the steps of:

a) preparing a plaster mold,

b) coating the mold with a casting retardant,

c) filling the coated mold with a silicon carbide slip having a bimodal grain size distribution,

d) dewatering the slip through the mold to produce a

casting having a thickness of between about 0.75 and

about 3 mm.

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23. The process of claim 22 wherein the casting retardant is selected from the group consisting of ammonium alginate, sodium alginate and polyacrylate acid.

24. The process of claim 22 wherein the casting retardant is ammonium alginate.

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