Plasma arc cutting system, including retaining caps, and other consumables, and related operational methods

Patent metadata

Field	Value
Publication number	US-10492286-B2
Application number	US-201715484196-A
Country	US
Kind code	B2
Filing date	Apr 11, 2017
Priority date	Apr 11, 2016
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

The invention features an inner cap for a liquid-cooled plasma arc torch. The inner cap includes a body having a longitudinal axis, a first end, and a second end. The first end includes an annular portion disposed proximate a torch tip. A liquid passage is formed within the body, is shaped to convey a liquid therethrough, and has a first set of ports formed in the annular portion. A gas passage is formed within the body, is shaped to convey a gas therethrough, and includes a second set of ports formed in the annular portion. The annular portion is configured such that subsets of ports in the first set of ports direct the liquid in a radial direction with respect to the longitudinal axis and alternate, in a rotational direction about the longitudinal axis, with subsets of ports in the second set of ports.

First claim

What is claimed is:

1. An inner cap for a liquid-cooled plasma arc torch, the inner cap comprising:
a substantially hollow body having a longitudinal axis, a first end, and a second end, the first end including an annular portion configured to be disposed proximate a torch tip of the plasma arc torch;
a liquid passage formed within the body and shaped to convey a liquid therethrough, the liquid passage including a first set of fluid exit ports formed in the annular portion; and
a gas passage formed within the body and shaped to convey a gas therethrough, the gas passage including a second set of fluid exit ports formed in the annular portion,
wherein the annular portion is configured such that subsets of ports in the first set of fluid exit ports direct the liquid out of the inner cap in a radial direction with respect to the longitudinal axis and alternate, in a rotational direction about the longitudinal axis, with subsets of ports in the second set of fluid exit ports that direct the gas out of the inner cap in a direction substantially parallel with the longitudinal axis,
wherein the first and second sets of fluid exit ports are spaced circumferentially around the annular portion and are positioned perpendicular or substantially perpendicular to each other to create a cross-flow of liquid and gas in the annular portion during operation of the torch.

2. The inner cap of claim 1 wherein the first set of ports is interleaved with the second set of ports to create a cross-flow of liquid and gas in the annular portion during operation of the plasma torch.

3. The inner cap of claim 1 wherein each port in the first set of ports is perpendicular or substantially perpendicular to a corresponding port in the second set of ports.

4. The inner cap of claim 1 wherein the first set of ports is oriented perpendicular to the longitudinal axis and the second set of ports is oriented parallel to the longitudinal axis.

5. The inner cap of claim 1 further including a plenum region formed at least partially within the body.

6. The inner cap of claim 5 further including a channel formed in the body and configured to transport fluid between an interior surface of the plenum region and an exterior surface of a nozzle of the plasma arc torch during operation of the plasma arc torch.

7. The inner cap of claim 6 wherein the channel extends circumferentially about the plenum region.

8. The inner cap of claim 1 wherein the inner cap is electrically insulative.

9. The inner cap of claim 1 wherein at least one of the first and second sets of ports includes slots in the body.

10. The inner cap of claim 1 wherein the gas passage is configured to transport a shield gas and the liquid passage is configured to transport a consumable coolant.

11. The inner cap of claim 1 further including a third set of ports aligned with the first set of ports to form a set of liquid passageways through the inner cap.

12. The inner cap of claim 1 wherein the first end includes a tapered portion adjacent to the annular portion.

13. The inner cap of claim 1 wherein the first end includes a neck portion.

14. The inner cap of claim 1 wherein the gas passage includes a first set of pathways fluidly connected to an interior region of the inner cap and the liquid passage includes a second set of pathways fluidly connected to interior and exterior regions of the inner cap.

15. The inner cap of claim 1 wherein the inner cap includes an outer portion and an inner portion, the outer portion at least substantially enclosing the inner portion.

16. The inner cap of claim 15 further comprising a snap feature configured to secure the outer portion to the inner portion.

17. The inner cap of claim 15 wherein the outer portion is formed of plastic and the inner portion is formed of a metal or metal alloy.

18. The inner cap of claim 1 wherein the first set of holes includes between five and nine holes and the second set of holes includes between six and eighteen holes.

19. The inner cap of claim 1 wherein a ratio of flow area between the second set of holes and a set of metering holes in the first end of the inner cap is at least 2:1.

20. The inner cap of claim 1 wherein the inner cap is symmetrical in the rotational direction.

21. An inner cap for a liquid-cooled plasma arc torch, the inner cap comprising:
an inner component having an interior surface and an exterior surface, the inner component defining a longitudinal axis of the inner cap;
an outer component circumferentially disposed around the inner component, the outer component having an interior surface, an exterior surface, and an annular region, the annular region extending beyond the inner component along the longitudinal axis toward a torch end of the inner cap;
a set of radial liquid passageways formed in the annular region of the outer component and oriented perpendicularly to the longitudinal direction, the set of radial liquid passageways configured to pass a liquid coolant from a nozzle of the plasma arc torch out of the inner cap, through a first set of fluid exit ports of the radial liquid passageways, to a shield of the plasma arc torch; and
a gas channel formed within the inner cap, the gas channel comprising:
a first portion of the gas channel defined, at least in part, by a portion of the exterior surface of the inner component and a portion of the interior surface of the outer component; and
a second portion of the gas channel defined within the annular region of the outer component, the second portion including a set of axial gas passageways configured to pass the gas out of the inner cap, through a second set of fluid exit ports of the axial gas passageways, to the shield of the plasma arc torch,
wherein, in the annular region, subsets of passageways in the set of liquid passageways and the set of gas passageways alternate in a rotational direction about the longitudinal axis to create a cross-flow of liquid and gas during operation of the plasma arc torch, and
wherein the first and second sets of fluid exit ports are spaced circumferentially around the annular portion and are positioned perpendicular or substantially perpendicular to each other.

Assignees

• Hypertherm Inc

Inventors

• Peters John
• Currier Brian J

Classifications

• B23K37/003

  Cooling means for welding or cutting · CPC title

• H05H1/28 Primary

  Cooling arrangements · CPC title

• B23K10/00

  Welding or cutting by means of a plasma · CPC title

• H05H1/3405

  Arrangements for stabilising or constricting the arc, e.g. by an additional gas flow · CPC title

• B23K10/006

  Control circuits therefor · CPC title