TECHNOLOGY NEWS:
Production line for stainless steel micro tubes with optical fibres
Stainless steel micro tubes with optical fibres are integrated into a number of different end products such as Optical Ground Wires (OPGW) and fibre optic submarine cable.
The optical fibres must be protected from external forces and harsh environmental conditions. Laser-welded, hermetically-sealed stainless steel micro tubes are ideal to meet these requirements. Nexans Deutschland has developed a universal welding machine – UNIWEMA – for the continuous production of longitudinally welded tubes.
The UNIWEMA 5L is the smallest type
and is capable of producing continuous butt welded stainless steel micro tubes with 1.0 to 5.5mm outer diameter in lengths of up to 50km containing up to 60 fibres embedded in thixotropic gel of approved quality. For the production of Fibre in the Steel Tube (FIST), a stainless steel strip is prepared and formed into a tube. During the forming process the optical fibres, welding gas and gel are introduced. The opposite strip edges are welded by a laser welding technique. The gel does not interfere with the welding area due a specially designed formula which Nexans is patenting and the welding heat does not affect the fibres. The weld seam quality is tested in-line by an eddy current testing device.
Two split clamp caterpillar capstan units, located downstream from the welding station, pull the micro tube through the machine. Two drawing dies located behind each capstan unit reduce the micro tube into the requested final diameter.
Because of different elongation charac-teristics of the steel tube and the fibres,
the design of the final cable requires an excess length of the fibres in the tube.
Nexans has developed special equipment which ensures that the percentage of excess length of the fibres is in accordance to the percentage of temporary elongation of the micro tube. In this set-up excess length in the range of 0.2 to 0.7 % can be reliably obtained. Finally the micro tube is spooled via dancer control onto a take-up.
Company: |
Nexans Deutschland Industries GmbH & Co KG |
Country: |
Germany |
Fax: |
+49 511 676-3777 |
Email: |
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Website: |