# US 7,608,797 B2 · High velocity thermal spray apparatus

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- Number: US 7,608,797 B2
- Document ID: US7608797B2
- Status: Granted
- Kind: B2
- Application number: 11/158,314
- Filed: 2005-06-21
- Published: 2006-02-23
- Granted: 2009-10-27
- Earliest claimed: 2004-06-22
- Inventors: Vladimir Belashchenko; Andrei Voronetski
- Web page: https://patentgrep.com/patent/US7608797B2

## CPC

- B05B 7/205: {the material to be sprayed being originally a particulate material}
- C23C 4/126: Detonation spraying
- C23C 4/129: Flame spraying
- B05B: SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES (spray-mixers with nozzles B01F25/72; processes for applying liquids or other fluent materials to surfaces by spraying B05D)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

A thermal spray apparatus is provided for thermal spraying a coating onto a substrate. The apparatus include a heating module for providing a stream of heated gas. The heating module is coupled to a forming module for controlling pressure and velocity characteristics of the stream of heated gas generated by the heating module. The thermal spray apparatus further includes a barrel capable of directing the stream of heated gas from the forming module. A powder injection module may be provided for introducing powder material into the stream of heated gas.

## Claims

### Claim 1

A thermal spray apparatus comprising:
a heating module for providing a stream of heated gas;
a forming module coupled to said stream of heated gas, said forming module comprising a first zone having an entrance coupled to said stream of heated gas and an exit coupled to a throat having a constant cross-sectional area, and a second zone having an entrance coupled to said throat and an exit;
a barrel coupled to said exit of said forming module;
a powder injection module comprising at least one powder injector for introducing powder material into said stream of gas; and
a shockwave generator;
where the ratio between the cross-sectional area of the exit of the second zone and the cross-sectional area of the throat =(0.5 to 0.8)2−(1.7+0.1 Pcc/Pa)2, wherein Pcc is absolute pressure in the heating module, and Pa is atmospheric pressure.

### Claim 2 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said shockwave generator is disposed between said forming module and said barrel.

### Claim 3 (depends on 2)

A thermal spray apparatus according to claim 2, wherein said shockwave generator comprises a step defined between said forming module and said barrel, and wherein a cross-sectional area of said barrel is greater than a cross-sectional area of said forming module exit.

### Claim 4 (depends on 3)

A thermal spray apparatus according to claim 3 wherein said cross-sectional area of said barrel is between about 1.05 to about 1.7 times greater than said cross-sectional area of said forming module exit.

### Claim 5 (depends on 1)

A thermal spray apparatus according to claim 1, wherein a portion of said barrel adjacent said forming module defines a converging zone having a cross-sectional area adjacent said forming module that is greater than a cross-sectional area away from said forming module.

### Claim 6 (depends on 5)

A thermal spray apparatus according to claim 5 wherein the length of said converging zone is between about 0.25 to about 2 times the diameter of the said exit of the forming module.

### Claim 7 (depends on 5)

A thermal spray apparatus according to claim 5, wherein said barrel comprises a generally cylindrical region between said forming module and said converging zone.

### Claim 8 (depends on 7)

A thermal spray apparatus according to claim 7, wherein the length of said generally cylindrical region is between about 0.25 to about 1.25 times the diameter of the said exit of the forming module.

### Claim 9 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said barrel comprises a second shockwave generator.

### Claim 10 (depends on 9)

A thermal spray apparatus according to claim 9, wherein said second shockwave generator comprising a stepped region having a downstream cross-sectional area greater than an upstream cross-sectional.

### Claim 11 (depends on 10)

A thermal spray apparatus according to claim 10, wherein said diameter of said downstream region is between about 1.02 to about 1.3 times greater than said diameter of said upstream region.

### Claim 12 (depends on 10)

A thermal spray apparatus according to claim 10, wherein said step is disposed between about 0.05 to about 0.25 times a length of said barrel from an end of said barrel.

### Claim 13 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said barrel comprises an expansion zone, said expansion zone comprising an exit diameter in the range of between about 1.02 to about 1.3 time greater than an entrance diameter of said expansion zone.

### Claim 14 (depends on 13)

A thermal spray apparatus according to claim 13, wherein the length of the barrel expansion zone is in the range of between about 0.05 to about 0.25 of total length of the barrel.

### Claim 15 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said at least one powder injector is oriented radial to said stream of gas.

### Claim 16 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said at least one powder injector is oriented parallel to said stream of gas.

### Claim 17 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said gas stream adjacent to said at least one powder injection has a pressure in the range of between about 0.04 to 0.08 MPa.

### Claim 18 (depends on 1)

A thermal spray apparatus according to claim 1, wherein the at least one powder injector is disposed adjacent to said shockwave generator.

### Claim 19 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said entrance of said first zone has a greater cross-sectional area than said exit of said first zone.

### Claim 20 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said forming module further comprises a generally cylindrical region disposed between said exit of said second zone and an exit of said forming module.

### Claim 21 (depends on 20)

A thermal spray apparatus according to claim 20 wherein said cylindrical region comprises a length in the range of between about 0.25 to about 2 times the diameter of said exit of said expansion zone.

### Claim 22 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said barrel comprises an inner sleeve and an outer sleeve, said inner sleeve having a thermal conductivity that is higher than a thermal conductivity of said outer sleeve.

### Claim 23 (depends on 22)

A thermal spray apparatus according to claim 22, wherein said inner sleeve comprises copper and said outer sleeve comprises stainless steel.

### Claim 24 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said heating module comprises a combustion module.

### Claim 25 (depends on 24)

A thermal spray apparatus according to claim 24, further comprising a secondary combustion region comprising a fuel supply and an oxidizer supply.

### Claim 26 (depends on 25)

A thermal spray apparatus according to claim 25, wherein said secondary combustion region is disposed at least partially around said barrel.

### Claim 27 (depends on 26)

A thermal spray apparatus according to claim 26, further comprising a secondary barrel disposed at least partially downstream of said secondary combustion region.

### Claim 28 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said heating module comprises a plasma torch.

### Claim 29 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said heating module comprises a resistive heating module.

### Claim 30 (depends on 1)

A thermal spray apparatus according to claim 1, wherein said powder injection module is configured to introduce a mixture of powder and shot peening media.

### Claim 31 (depends on 1)

A thermal spray apparatus according to claim 1, further comprising an injection nozzle for introducing shot peening media in to said stream of gas.

### Claim 32

A thermal spray apparatus comprising:
a forming module comprising at least two sub-forming blocks, each sub-forming block coupled to a gas stream and each sub-forming block comprising a converging zone having an inlet diameter that is greater than an exit diameter, a throat having a constant cross-sectional area, and an expansion zone having an exit diameter that is greater than an inlet diameter;
a barrel coupled to an exit of each sub-forming block; and
a shockwave generator;
where the ratio between the cross-sectional area of said exit of said expansion zone and the cross-sectional area of the throat =(0.5 to 0.8)2−(1.7+0.1 Pcc/Pa)2, wherein Pcc is absolute pressure in a heating module configured to provide said gas stream, and Pa is atmospheric pressure.

### Claim 33 (depends on 32)

A thermal spray apparatus according to claim 32, wherein a cross-sectional area of said barrel is greater than a cumulative cross-sectional area of said exits of said sub-forming blocks.

### Claim 34 (depends on 33)

A thermal spray apparatus according to claim 33, wherein said cross-sectional area of said barrel is between about 1.05 to about 1.7 times greater than said cumulative cross-sectional area of said exits of said sub-forming blocks.

### Claim 35 (depends on 33)

A thermal spray apparatus according to claim 33, further comprising a powder injector introducing powder material into said gas stream.

### Claim 36

A thermal spray apparatus comprising:
a forming module coupled to a stream of gas, said forming module comprising a converging zone having an entrance and an exit, said entrance having a greater cross-sectional area than said exit; a throat having a constant cross-sectional area, said throat coupled to said exit of said converging zone; and an expansion zone having an entrance and an exit, said entrance having a cross-sectional area smaller than a cross-sectional area of said exit, said entrance of said expansion zone coupled to said throat;
a powder injector introducing a powder material into said stream of gas, said powder injector oriented parallel to an axis of said forming module and disposed at least partially within said forming module, said powder injector having a cross-sectional profile that at least partially defines said cross-sectional areas of at least one of said converging zone, said throat, or said expansion zone; and
a shockwave generator;
where the ratio between the cross-sectional area of said exit of said expansion zone and the cross-sectional area of the throat =(0.5 to 0.8)2−(1.7+0.1 Pcc/Pa)2, wherein Pcc is absolute pressure in a heating module configured to provide said gas stream, and Pa is atmospheric pressure.

### Claim 37 (depends on 36)

A thermal spray apparatus according to claim 36, further comprising at least one passage introducing a gas for influencing a temperature of said gas stream.

### Claim 38 (depends on 37)

A thermal spray apparatus according to claim 37, wherein said gas comprises a non-combustible gas.

### Claim 39 (depends on 37)

A thermal spray apparatus according to claim 37, wherein said gas comprises a combustible gas.