Welding torch system for use in welding or cutting operations, welding torch for use in such a welding torch system and method for welding using such a welding torch system or such a welding torch

Patent metadata

Field	Value
Publication number	US-9802266-B2
Application number	US-201514636901-A
Country	US
Kind code	B2
Filing date	Mar 3, 2015
Priority date	Mar 3, 2015
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

Welding torch system for use in welding or cutting operations during which fume is created. The welding torch system has a welding torch comprising a contact tip holder and a coaxial nozzle comprising an inner shield gas conduit having a shield gas outlet for supplying a shield gas. The inner shield gas conduit surrounds the contact tip holder. An outer shell at least partly surrounds said inner shield gas conduit. The welding torch system further comprises a shield gas generator and supply unit for supplying shield gas through the shield gas outlet and a fume extracting assembly for extracting fume and ambient air. The welding torch system is arranged for—during operation—supplying shield gas through the shield gas outlet at a velocity between about 1.5 m/s and 10 m/s. By operating the fume extracting assembly to generate a flow of between 10 and 100 m 3 /h, preferably a flow of about 55 m 3 /h a reduction in the area of 90%-95% of hazardous fumes can then be realized. A welding torch for use in such a system has an inner shield gas conduit having an end portion with an inner surface of which the diameter decreases towards the shield gas outlet. In a method for welding the shield gas is supplied through the shield gas outlet at a velocity between about 1.5 m/s and 10 m/s.

First claim

The invention claimed is:

1. Welding torch system for use in welding or cutting operations during which fume is created, said welding torch system including a welding torch comprising:
a contact tip holder having formed therein a longitudinal passageway with a head end through which can be supplied welding wire having a free end forming a contact tip;
a coaxial nozzle comprising an inner shield gas conduit having a shield gas outlet for supplying a shield gas, said inner shield gas conduit surrounding said contact tip holder, an outer shell at least partly surrounding said inner shield gas conduit, said outer shell having a head end, wherein between an inner surface of said outer shell and an outer surface of said inner shield gas conduit a fume extracting passageway is formed and wherein a plurality of openings is provided in a distal end of the outer shell for extracting ambient air and fume into the coaxial nozzle;
said welding torch system further comprising:
a shield gas generator and supply unit operatively connectable to the inner shield gas conduit for—during operation—supplying shield gas through the shield gas outlet; and
a fume extracting assembly operatively connectable to the fume extracting passageway for—during operation—extracting fume and ambient air;
wherein the welding torch system is arranged for—during operation—supplying shield gas through the shield gas outlet at a velocity between about 1.5 m/s and 10 m/s;
and wherein the outer shell is provided with a number of longitudinally extending slots, each slot communicating with the fume extracting passageway, which slots are distributed evenly in circumferential direction of the outer shell.

2. Welding torch system according to claim 1 , wherein the inner shield gas conduit has an end portion having an inner surface of which the diameter decreases towards the shield gas outlet.

3. Welding torch system according to claim 2 , wherein the inner surface of the end portion is configured for—during operation—generating an undisturbed flow of shield gas.

4. Welding torch system according to claim 1 , wherein the shield gas outlet has a diameter between 8 and 12 mm.

5. Welding torch system according to claim 1 , wherein the contact tip holder has a conical end portion having an outer surface with a diameter which decreases towards the head end.

6. Welding torch system according to claim 2 , wherein the distance between the outer surface of the conical end portion of the contact tip holder and the inner surface of the conical end portion of the inner shield gas conduit is uniform in longitudinal direction.

7. Welding torch system according to claim 1 , wherein the distance in longitudinal direction between the head end of the contact tip holder and a plane defined by the shield gas outlet of the inner shield gas conduit is less than 5 mm.

8. Welding torch system according to claim 1 , wherein the inner surface of the distal end of the outer shell has a diameter which decreases towards the head end of the distal end of the outer shell and wherein the slots extend from the portion of the outer shell where the inner surface has the largest diameter up to an operating distance from the distal end of the head end of the outer shell.

9. Welding torch system according to claim 8 , wherein the operating distance is at least 3 mm.

10. Welding torch system according to claim 1 , wherein the fume extracting assembly is arranged for—during operation—generating a flow of between 10 and 100 m 3 /h.

11. Welding torch system according to claim 8 , wherein the fume extracting assembly is arranged for—during operation—generating a flow with such a value and the operating distance is chosen such for—during operation—creating a circumferential lee zone around the distal end of the outer shell in which no extraction force is exerted on fume.

12. Welding torch system according to claim 1 , wherein the welding torch system is arranged for—during operation—reducing hazardous fumes by at least 90%-95%.

13. Welding torch for use in a welding torch system according to claim 1 , wherein the welding torch comprises:
a contact tip holder having formed therein a longitudinal passageway with a head end through which can be supplied welding wire having a free end forming a contact tip;
a coaxial nozzle comprising an inner shield gas conduit having a shield gas outlet for supplying a shield gas, said inner shield gas conduit surrounding said contact tip holder, an outer shell at least partly surrounding said inner shield gas conduit, said outer shell having a head end, wherein between an inner surface of said outer shell and an outer surface of said inner shield gas conduit a fume extracting passageway is formed and wherein a plurality of openings are provided in a distal end of the outer shell for extracting ambient air and fume into the coaxial nozzle;
wherein the inner shield gas conduit has an end portion having an inner surface of which the diameter decreases towards the shield gas outlet.

14. Welding torch according to claim 13 , wherein the shield gas outlet has a diameter between 8 and 12 mm.

15. Welding torch according to claim 13 , wherein the outer shell is provided with a number of longitudinally extending slots, each slot communicating with the fume extracting passageway, which slots are distributed evenly in circumferential direction of the outer shell.

16. Welding torch according to claim 15 , wherein the inner surface of the distal end of the outer shell has a diameter which decreases towards the head end of the distal end of the outer shell and wherein the slots extend from the portion of the outer shell where the inner surface has the largest diameter up to an operating distance from the distal end of the head end of the outer shell.

17. Welding torch according to claim 16 , wherein the operating distance (OD) is at least 3 mm.

18. Method for welding using a welding torch system according to claim 1 , wherein the method comprises during welding the steps of:
supplying shield gas through the shield gas outlet by operating the shield gas generator and supply unit; and
extracting fume and ambient air by operating the fume extracting assembly;
wherein the shield gas is supplied through the shield gas outlet at a velocity between about 1.5 m/s and 10 m/s, and
wherein the outer shell is provided with a number of longitudinally extending slots, each slot communicating with the fume extracting passageway, which slots are distributed evenly in circumferential direction of the outer shell, wherein the inner surface of the distal end of the outer shell has a diameter which decreases towards the head end of the distal end of the outer shell and wherein the slots extend from the portion of the outer shell where the inner surface has the largest diameter up to an operating distance from the distal end of the head end of the outer shell, and wherein by operating the fume extracting assembly a flow is generated with such a value and the operating distance is chosen to be at least 3 mm such that a circumferential lee zone is created around the distal end of the outer shell in which no extraction force is exerted on fume.

19. Method for welding according to claim 18 , wherein a flow of between 10 and 100 m 3 /h is generated by operating the fume extracting assembly.

20. Method for welding according to claim 18 , wherein the amount of hazardous fumes is reduced by at least 90%-95%.

Assignees

• Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno

Inventors

• Moons Andreas Mattheus Maria
• Henquet Ellemieke Mary-Rose
• Knoll Bastiaan

Classifications

• B23K9/295

  using consumable wire electrodes · CPC title

• B23K9/173 Primary

  and of a consumable electrode · CPC title

• B23K9/325

  Devices for supplying or evacuating shielding gas · CPC title