Method for the continuous production of optical fibre waveguide sensors mounted in a perforated metal hollow profile

Patent metadata

Field	Value
Publication number	US-2021199910-A1
Application number	US-202017111607-A
Country	US
Kind code	A1
Filing date	Dec 4, 2020
Priority date	Dec 5, 2019
Publication date	Jul 1, 2021
Grant date	—

Abstract

A method (100) for the continuous production of a thin-walled, perforated metal hollow profile with one or more fibre waveguides mounted therein. The method includes supplying (102) of a flat metal strip at a first supply rate to a deforming device, which continuously deforms the metal strip into a metal hollow profile with a slot running in a longitudinal direction. Two opposite edges of the metal strip deformed into the metal hollow profile that lie flush against one another in a contact region extending in the longitudinal direction of the metal hollow profile are continuously welded to one another (110), drawn off from the welding region and perforated. The method according to the invention comprises furthermore positioning a protective tube reaching into the welded metal hollow profile on the draw-off side to beyond the perforation point and supplying (111) one or more fibre waveguides from one or more fibre unwinders via the protective tube, such that the fibre waveguide or waveguides are introduced into the perforated metal hollow profile from the guide or protective tube downstream of the perforation point in the drawing-off direction. The perforated metal hollow profile with the fibre waveguide or fibre waveguides mounted therein is received in a receiving unit (124).

First claim

1 . A method for the continuous production of a thin-walled, perforated metal hollow profile with one or more optical fibre waveguides mounted therein, comprising:
supplying a flat metal strip at a first supply rate to a deforming device, continuously deforming the supplied flat metal strip into a metal hollow profile with a slot running in a longitudinal direction, wherein two opposite edges of the metal strip deformed into the metal hollow profile lie flush against one another in a contact region extending in the longitudinal direction of the metal hollow profile and are continuously welded to one another in a welding device, drawing off the welded metal hollow profile from the welding region,
said method furthermore comprising:
perforating the welded metal hollow profile using a drilling device arranged at a perforation point beyond the welding device on the draw-off side,
positioning a guide or protective tube running through under the welding region and reaching into the welded metal hollow profile on the draw-off side to beyond the perforation point,
supplying one or more optical fibre waveguides from one or more fibre unwinders via the guide or protective tube, such that the optical fibre waveguide or waveguides are introduced into the perforated metal hollow profile from the guide or protective tube downstream of the perforation point in the drawing-off direction, and
receiving the perforated metal hollow profile with the fibre waveguide or fibre waveguides mounted therein in a receiving unit.

2 . The method according to claim 1 , furthermore comprising:
reducing the cross-sectional dimensions of the welded metal hollow profile to a desired end size before the perforating.

3 . The method according to claim 1 , wherein the guide or protective tube protrudes into the metal hollow profile beyond the perforation point by a certain first length and is withdrawn from the metal hollow profile by a certain second length and/or is axially turned by a specified angle after a specified number of drilled holes.

4 . The method according to claim 1 , wherein the perforating comprises the drilling of holes into a wall of the metal hollow profile by means of a laser.

5 . The method according to claim 1 , furthermore comprising:
introducing a filler gel for embedding the fibre waveguide or waveguides in the filler gel within the metal hollow profile.

6 . The method according to claim 1 , wherein the optical fibre waveguide or waveguides is/are introduced into the perforated metal hollow profile with an excess length, further comprising:
elastic stretching of the perforated metal hollow profile by introducing a tensile force to the perforated metal hollow profile, introducing the optical fibre waveguide or waveguides and possibly the filler gel into the stretched metal hollow profile, and ending of the elastic stretching after the introduction of the optical fibre waveguide or waveguides and before the reception in the receiving unit.

7 . The method according to claim 6 , further comprising:
continuously determining the lengths of the optical fibre waveguide or waveguides supplied in the unstretched state and of the metal hollow profile taken away after ending the elastic stretching, with the optical fibre waveguide or waveguides introduced therein, and determining control or controlled variables for controlling one or more process parameters from the non-exhaustive list comprising the supply rate of the strip, power of the welding device, temperature and throughflow quantity of the filler gel per unit of time, feed rate after the welding and tensile force for the elastic stretching, in order to set an excess length of the optical fibre waveguides received in the metal hollow profile.

8 . The method according to claim 1 , wherein the welding is performed by means of a laser welding device.

9 . A device for the continuous production of thin-walled, perforated metal hollow profiles with one or more optical fibre waveguides mounted therein, comprising:
a supplying unit configured for supplying a flat metal strip, a deforming unit, which deforms the flat metal strip into the metal hollow profile and around the supplied fibre waveguide such that the opposite edges of the flat metal strip abut flush against one another in a butt-jointed manner, guide means between which the edges are held so as to lie flush against one another, a welding device, which welds together the edges lying flush against one another between the guide means,
wherein the device furthermore comprises
a drilling device arranged beyond the welding device on the draw-off side for perforating the welded metal hollow profile,
a supplying device with one or more fibre unwinders, from which optical fibre waveguides are unwound and are introduced via a guide or protective tube through under the welding device and the drilling device into the welded metal hollow profile, wherein the guide or protective tube runs through under the welding region and reaches to beyond the perforation point in the welded metal hollow profile, and
a receiving unit, which receives the perforated metal hollow profile with the optical fibre waveguide or optical fibre waveguides embedded therein.

10 . The device according to claim 9 , furthermore comprising:
a device for reducing the cross-sectional dimensions of the welded metal hollow profile arranged between the welding device and the drilling device.

11 . The device according to claim 9 , wherein the guide or protective tube is mounted in an axially displaceable and/or rotatable manner, and can be turned by a certain angle and/or can be withdrawn by a certain distance from the metal hollow profile by means of a drive after a specified number of drilled holes.

12 . The device according to claim 9 , wherein, at the wavelength of a laser of the drilling device used for the perforating, the material of the guide or protective tube has a lower energy absorption or a greater reflectivity than the material of the metal hollow profile.

13 . The device according to claim 9 , further comprising:
a gel filling unit, from which a filler gel can be introduced into the welded metal hollow profile via an annular gap set at a distance from an outlet opening for the fibre waveguide or waveguides.

14 . The device according to claim 13 , wherein the gel filling unit has a heatable reservoir, a heatable filling hose and/or a heatable filling head.

15 . The device according to claim 9 , further comprising:
a device for elastically stretching the perforated metal hollow profile, wherein the fibre waveguide or waveguides is/are introduced into the stretched metal hollow profile in the unstretched state, and wherein the elastic stretching is ended before the metal hollow profile is sent to the receiving device.

Assignees

• Nexans

Inventors

• Egerer Ralf
• Dinkel Steven
• Lange Nico
• Petersen Olaf

Classifications

• G02B6/4488 Primary

  using metallic tubes · CPC title

• G02B6/4484

  with desired surplus length between fibres and protection features · CPC title

• B23K26/21 Primary

  by welding · CPC title

• B23K9/167

  and of a non-consumable electrode · CPC title

• B23K9/173

  and of a consumable electrode · CPC title