Underwater laser processing device including chamber with partitioning wall

• US 5,977,515 A
• Filed: 10/04/1995
• Issued: 11/02/1999
• Est. Priority Date: 10/05/1994
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Matsumoto, Toshimi, Uraki, Keiichi, Satsuta, Toshitaka, Nakamura, Mitsuo, Hayashi, Eisaku, Yamauchi, Hiroshi, Morinaka, Ren, Onuma, Tsutomu, Onuma, Akira, Tamai, Yasumasa
• Primary Examiner(s): MILLS, GREGORY L
• Application Number:
  US08/539,074
• Time in Patent Office: 1,490 Days
• Field of Search: 219/121.6, 219/121.63, 219/121.65, 219/121.67, 219/121.75, 219/121.78, 219/121.79, 219/121.8, 219/121.84, 219/121.86
• US Class Current: 219/121.84
• CPC Class Codes: B23K 26/067 Dividing the beam into multiple beams, e.g. multifocusing
• CPC Class Codes: B23K 26/1224 in vacuum
• CPC Class Codes: B23K 26/1423 the flow carrying an electric current
• CPC Class Codes: B23K 26/146 the fluid stream containing a liquid
• CPC Class Codes: B23K 26/1476 Features inside the nozzle for feeding the fluid stream through the nozzle
• CPC Class Codes: B23K 26/348 in combination with arc heating, e.g. TIG [tungsten inert gas], MIG [metal inert gas] or plasma welding laser beam for starting a welding or cutting arc B23K9/067

Abstract

An underwater laser processing system has a laser torch; a laser torch driving mechanism for changing a laser emission position of the laser torch; and a chamber with one end opened to an external environment, which contains the laser torch; wherein a partitioning wall for preventing permeation of water is provided between a free end of the chamber and the laser torch. The system is used for detecting a sensitized portion and repairing it at one time using a sensitization detecting arrangement. Moreover, it is used for forming an alloying layer by melting a sprayed coating film, and for forming a new surface layer by emitting a laser beam through a solution containing a metal component.

Claims

1. An underwater laser processing system comprising:

a laser torch including a condenser lens;

a laser torch driving mechanism for changing an emission position of said laser torch; and

a laser torch containing chamber for containing said laser torch and said laser torch driving mechanism;

wherein said chamber for containing said laser torch has, at a portion for emitting laser light, a water-tight partitioning plate movable for allowing said laser torch to come in or go out of said chamber for containing said laser torch;

a processing chamber provided at a portion for emitting laser light and processing a structure to be processed in such a manner as to be in contact with said structure to be processed in order not to allow water to flow in said processing chamber; and

said processing chamber is provided integrally with, or independently from, said chamber for containing said laser torch, and is provided with an inert gas injection mechanism, an inert gas exhausting mechanism, and a water discharging mechanism.

2. An underwater laser processing system according to claim 1, wherein said partitioning plate is mounted so as to be moveable, and further including an opening/closing mechanism for moving said partitioning wall to open said chamber.

3. An underwater laser processing system according to claim 2, further including a laser torch driving mechanism for advancing said laser torch toward a surface of a structure to be processed.

4. An underwater laser processing system according to claim 1, wherein part of said partitioning plate is made of a material capable of transmitting a laser beam.

5. An underwater laser processing system according to claim 1, wherein said chamber includes a compartment having a mechanism for preventing permeation of water at said open end of said chamber when said chamber contacts the surface of an underwater structure, and a mechanism for expelling water from a space bounded by said open end, an outer wall of said chamber connected to said open end and said partitioning plate by introducing gas into a space.

6. An underwater laser processing system according to claim 5, wherein said mechanism provided at said open end of said chamber for preventing permeation of water comprises at least one of a skirt mechanism formed of an elastic body having a predetermined flexibility so as to be deformable in accordance with a shape of an underwater structure to be processed, a curtain mechanism for jetting a high pressure shield gas, and a curtain mechanism for jetting high pressure water.

7. An underwater laser processing system according to claim 5, wherein the inner surface of the chamber, which has said mechanism for preventing permeation of water at a portion to be contacted with the surface of an underwater structure and said mechanism for substituting water for gas, has an insulating property.

8. An under waterlaser processing system according to any of claims 1 to 5, wherein at least one of said chambers includes at least one of a water discharging mechanism, a gas injecting mechanism, a gas exhausting mechanism, a dust exhausting mechanism, a gas flow rate monitoring mechanism, a pressure monitoring mechanism, a temperature monitoring mechanism, and a moisture monitoring mechanism.

9. An underwater laser processing system according to any of claims 1 to 5, wherein at least one of said chambers includes at least one of a gas injecting mechanism for drying the interior of said chamber, a side gas shield mechanism for removing evaporated material and fine particles generated from the surface of a target structure upon processing, and a gas injecting mechanism for drying said laser torch.

10. An underwater laser processing system according to any of claims 1 to 5, further including a mechanism for holding laser emitting optics at a temperature in the range of ±

30°

C. on the basis of a temperature of water around said system.

11. An underwater laser processing system according to any of claims 1 to 5, further including a transmission tube for shielding an optical fiber element from water in the range up to a water surface, said optical fiber element being adapted to transmit a laser beam to a main body of said system through the water environment.

12. An underwater laser processing system according to any of claims 1 to 5, wherein said system is used for underwater processing for emitting a laser beam to an underwater structure.

13. An underwater laser processing system according to any of claims 1 to 5, wherein said system is used for surface treatment, said surface treatment comprising the step of forming an alloying layer on the surface of an underwater structure made of a stainless steel, said alloying layer having the following average composition (wt %) in the region of a depth of 20 μ

m from the surface;

0≦

C≦

0.02

0≦

Si≦

1

0≦

Mn≦

2

0≦

P≦

0.045

10.50≦

Ni≦

15

16.5≦

Cr≦

24

2≦

Mo≦

3

0≦

N≦

0.22

0≦

Nb≦

0.5

0≦

Ti≦

0.5

0≦

Zr≦

0.5

0≦

Pt≦

0.5

0≦

Pd≦

0.5

Fe, and inevitable impurities;

balance.

14. An underwater laser processing system according to any of claims 1 to 5, wherein said system is used for surface treatment, said surface treatment comprising the step of forming an alloying layer on the surface of an underwater structure made of a Ni alloy, said an alloying layer having the following average composition (wt %) in the region of a depth of 20 μ

m from the surface;

0≦

C≦

0.03

0≦

Si≦

0.5

0≦

Mn≦

1

0≦

P≦

0.03

5.5≦

Fe≦

10

14≦

Cr≦

17

0≦

Nb≦

0.5

0≦

Ti≦

0.5

0≦

Zr≦

0.5

0≦

Pt≦

0.5

0≦

Pd≦

0.5

Ni and inevitable impurities;

balance.

15. An underwater laser processing system comprising:

a laser torch;

a laser torch driving mechanism for changing a laser emission position of said laser torch;

a chamber with one end opened to an external environment, which chamber contains said laser torch;

a partitioning wall for preventing permeation of water to said laser torch being provided between a free end of said chamber and said laser torch, said partitioning wall including an opening/closing mechanism;

a laser torch driving mechanism provided for advancing said laser torch to a surface of a structure to be processed; and

wherein an inner surface of said chamber has a mechanism for preventing permeation of water at a portion to be contacted with a surface of an underwater structure, a mechanism for substituting water for gas, and has an insulating property.

16. An underwater laser processing system according to claim 15, wherein:

said laser torch including a condenser lens;

said chamber for containing said laser torch and said laser torch driving mechanism;

said chamber for containing said laser torch has, at a portion for emitting laser light, said partitioning wall movable for allowing said laser torch to come in or go out of said chamber for containing said laser torch, or a fixed laser light transmission shielding plate;

a processing chamber provided at a portion for emitting laser light and processing a structure to be processed in such a manner as to be in contact with said structure to be processed in order not to allow water to flow in said processing portion; and

said processing chamber is provided integrally with, or independently from, said chamber for containing said laser torch, and is provided with an inert gas injection mechanism, an inert gas exhausting mechanism, and a water discharging mechanism.