PLASMA ARC TORCH CUTTING COMPONENT WITH OPTIMIZED WATER COOLING

• US 20090026180A1
• Filed: 08/07/2008
• Published: 01/29/2009
• Est. Priority Date: 02/09/2007
• Status: Active Grant

• Current Assignee: Hypertherm Incorporated
• Original Assignee: Hypertherm Incorporated
• Inventors: Cook, David Jonathan, Yang, Yong
• Granted Patent: US 8,829,385 B2
• Time in Patent Office: Days
• US Class Current: 219/121.490
• CPC Class Codes: B23K 10/00 Welding or cutting by means of a plasma
• CPC Class Codes: H05H 1/34 Details, e.g. electrodes, nozzles
• CPC Class Codes: H05H 1/3436 Hollow cathodes with internal coolant flow
• CPC Class Codes: H05H 1/3442 Cathodes with inserted tip
• CPC Class Codes: H05H 1/3457 Nozzle protection devices

Abstract

A nozzle, retaining cap, or shield for a plasma arc torch that includes a surface defining a conductive contact portion for exchanging heat with an adjacent torch component. The adjacent torch component can be a retaining cap, electrode or nozzle. The surface of the nozzle, retaining cap, or shield can also at least partially define a cooling channel having a curvilinear surface. A sealant portion can be positioned between the conductive contact portion and the cooling channel. The sealant portion can form or create a fluid barrier between the cooling channel and the conductive portion.

Claims

1. A shield for a plasma arc torch comprising:

an exterior surface defining a conductive contact portion for exchanging heat with an adjacent torch component;

a fluid flow path defined, at least in part, by a curvilinear surface; and

a sealing component disposed between the conductive contact portion and the fluid flow path.

2. The shield of claim 1 wherein the sealing component further comprises an elastomeric seal.

3. The shield of claim 1, wherein the fluid flow path forms at least a portion of a toroidal chamber.

4. The shield of claim 1, wherein the fluid flow path comprises at least a portion of a fluid chamber that includes a convex curvilinear portion and a concave curvilinear portion, the convex curvilinear portion promoting fluid flow into the concave curvilinear portion.

5. The shield of claim 1, wherein the contact portion provides axial and radial alignment of the shield to the adjacent torch component.

6. The shield of claim 1, wherein the conductive contact portion includes a layer of a conductive metal or metal oxide disposed thereon.

7. A cooling and sealing structure for coupling and providing heat transfer between a shield and an adjacent torch component for a plasma arc torch, the structure comprising:

a shoulder portion that provides a contact surface between the shield and the adjacent torch component;

a convective cooling channel including a concave curvilinear portion; and

a sealing component positioned between the shoulder portion and the convective cooling channel.

8. The structure of claim 7, wherein the convective cooling channel further comprises a convex curvilinear portion and a tangential connection portion, the tangential connection portion disposed between the convex curvilinear portion and the concave curvilinear portion.

9. The structure of claim 7, wherein the convective cooling channel includes a bulbous portion.

10. The structure of claim 7, wherein the convective cooling channel comprises a toroidal shape.

11. The structure of claim 7, wherein the conductive contact portion, the convective cooling channel, and the sealing component are part of the shield.

12. A cooling and sealing structure for coupling and providing heat transfer between a shield and at least one adjacent plasma torch component, the structure comprising:

means for conductively cooling between the shield and the at least one adjacent torch component;

means for convectively cooling at least a portion of the plasma torch by reducing stagnation of the cooling fluid; and

a sealing means for providing a fluid seal between the conductively cooling means and the convectively cooling means.

13. The cooling and sealing structure of claim 12 wherein the adjacent torch components include at least one of a nozzle or a retaining cap.

14. The cooling and sealing structure of claim 12 wherein the means for conductive cooling, the means for providing convective cooling, and the sealing means are at least partially located on a single plasma torch component.

15. The cooling and sealing structure of claim 12 wherein the means for providing effective convective cooling is defined between adjacent torch components.

16. The cooling and sealing structure of claim 12, wherein the means for conductive cooling also provides at least one of radial or axial alignment between the adjacent torch components.

17. A plasma arc torch comprising:

a torch body connected to a power supply;

an electrode disposed within the torch body;

a shield with an exterior surface defining a conductive contact portion for exchanging heat with an adjacent torch component and a convective cooling structure comprising a concave curvilinear portion that defines at least a portion of a cooling channel.

18. The plasma arc torch of claim 17 further comprising a sealing component dimensioned and configured to provide a fluid seal between the conductive contact portion and the convective cooling structure.

19. The plasma arc torch of claim 17 wherein the sealing component is located on at least one of the torch component or the adjacent torch component.

20. A plasma arc torch system comprising:

a power supply;

a torch body connected to the power supply;

an electrode disposed within the torch body;

a controller that controls the flow of gas to the electrode;

a shield having a substantially hollow body capable of receiving a nozzle, the shield comprising;

a first cooling means for conductive cooling between the shield and an adjacent torch component;

a second cooling means for providing convective cooling of a portion of the plasma torch without stagnation of a cooling fluid flow; and

a sealing means disposed between the first cooling means and the second cooling means to provide a fluid seal.

21. A method of cooling a plasma torch component comprising:

exchanging heat from a shield with an adjacent torch component through a conductive contact portion;

flowing a cooling fluid through a cooling channel having a curvilinear surface, the curvilinear surface configured to prevent fluid stagnation; and

providing a barrier comprising a sealing component between the conductive contact portion and the cooling channel.

22. A method of manufacturing a shield for use with a plasma torch, the shield comprising:

forming a conductive contact surface on the shield for exchanging heat with an adjacent torch component;

creating a cooling channel with a shaped portion having a curvilinear surface; and

forming a sealant groove between the surface and the shaped portion.

23. The method of claim 22 wherein the sealant groove further comprises a sealing component that includes at least one of an o-ring or elastomeric seal.

24. A shield for a plasma arc cutting torch having a substantially hollow body capable of receiving a nozzle, the shield comprising:

an exterior surface that includes a portion having a curvilinear profile that at least partially defines a flow path for a cooling fluid.