SE465914B - PROCEDURES FOR PREPARING AN ELECTRIC SUPPLY PIPE CONSISTING OF AATMINSTONE INSULATED INSULATED, CONCENTRIC SINGLE CONDUCTORS IN THE FORM OF METAL PIPES - Google Patents

Description

465 914 10 15 20 25 30 35 .com such a process for the production of a 2 lig is placed vertically - it is absolutely required that the metal pipes are force-bonded to the adjacent plastic layers.

The object of the present invention is to provide a pipe system which enables economical production while meeting the requirements for the position and wall thickness of the pipes and which ensures a force-tight connection between the individual pipes while maintaining the electrically insulating layer. The object is achieved in the initially stated method according to the invention in that an electrically insulating plastic layer is first extruded on a first, seamlessly drawn copper pipe, that the coated copper pipe is inserted into a second, seamlessly drawn copper pipe with a larger inner diameter and that the second the copper pipe is then firmly shrunk on the plastic layer of the first copper pipe.

It is essential that the plastic layer is deformed to a small extent, so that a solid connection is obtained between the two pipes.

According to a particularly advantageous embodiment of the invention, the second metal tube is also coated with plastic, after this second metal tube has been tightened or crimped, and the composite or dressing tube thus obtained is inserted into a third metal tube, whereupon it is firmly applied to the plastic layer of the second metal tube. In this way an object is obtained with three mutually electrically insulated metal pipes, which can be used as electrical conductors.

The tightening or crimping is advantageously achieved by pulling the tube through a drawing matrix, whereby during the drawing the inner tube is supported by an M held in the area of the drawing matrix. When large forces are required to obtain the force-bonded connection between the pipe to be applied and the plastic layer, a deformation of the inner pipe is counteracted by means of the mandrel. 10 15 20 25 30 35 465 914 3 In order for the plastic layer present between the pipes to be evenly thick, this layer is advantageously applied by extrusion.

A particularly economical production is obtained if a plurality of metal pipes are interconnected at the ends and these pipes are fed through an extrusion machine, which applies a plastic layer to the pipe surface. After cooling and curing the plastic, the pipes are separated at the connection points and each separated pipe is inserted into a metal pipe and the metal pipe is pulled down on the plastic layer, whereby the inner pipe is supported by means of a mandrel. The dressing tubes thus produced are reconnected to each other at the ends and fed through an additional extrusion machine, which creates an additional plastic layer on the second tube. After cooling and hardening of this plastic layer, the dressing pipes are cut at the connection points and each cut dressing pipe is inserted into a metal pipe, which is applied to the plastic layer of the dressing pipe, the inner pipe also being supported by a mandrel in this case.

The plastic-coated metal pipe or dressing pipe is inserted into the larger metal pipe with light play and possibly using lubricant. It is essential that the outer diameter of the plastic layer and the inner diameter of the larger tube do not differ significantly from each other, so that no major difficulties arise in the subsequent tightening of the outer tube. A clearance or a diameter difference of about 1 mm is therefore preferred. To improve the sliding, it is convenient to coat the upper surface of the plastic layer with a lubricant, preferably with a paraffin-type oil. In order to avoid damage to the plastic layer during insertion, the inner edge of the present outer tube is preferably broken before the insertion of the plastic-coated metal tube or the dressing tube.

The invention is described in more detail with reference to the exemplary embodiment shown in Figs. 1-5. 465 914 10 15 20 25 30 35 4 Fig. 1 shows the supply line in built-in condition.

Figures 2-5 show measures in the procedure for the production of the supply line.

The supply line 1 is arranged in a pipe 2 with a vertical position. For the supply of an underwater pump (not shown) with lubricant or coolant, there is a channel 3, while the annulus 4 between the supply line 1 and the pipe 2 serves for the return of the coolant or lubricant.

In addition, the supply line 1 serves to supply the underwater pump with electrical energy.

For this purpose there are three concentric copper pipes 5, 6 and 7, which are electrically insulating against each other by means of plastic layers 8 and 9, preferably of polyethylene.

The copper conductors 5, 6 and 7 transmit the three phases of the three-phase current. The copper pipes 5, 6 and 7 and the polyethylene layers 8 and 9 are forcibly connected to each other, so that when arranged vertically no longitudinal axial displacement of the pipes 5, 6 and 7 is obtained. The copper pipes 5, 6 and 7 are seamless drawn pipes.

For example, the inner tube has a dimension of 19x1, 5, ie 19 mm outer diameter and 1.5 mm wall thickness. The adjacent polyethylene layer 8 has a wall thickness of 1.5 mm. The centrally located copper pipe 6 then has the dimension 25xl, 5. The adjacent polyethylene layer 9 also has a wall thickness of 1.5 mm. For the outer copper pipe 7, a dimension of 3lxl, 5 mm is then obtained.

In a modification of the mentioned dimensions, the wall thickness of the copper pipes 5, 6 and 7 can decrease from the inside and outwards, whereby it should be sought that the pipe cross-section of the pipes 5, 6 and 7 is equal.

Optionally, it may be advantageous to apply an additional plastic layer to the copper pipe 7.

For the production of the supply line 1, a plurality of copper pipes 5 are first interconnected by means of per se known connecting means 10 and they are passed through an extruder 11, which applies the polyethylene layer flf to the copper pipe 5. By means of a coupling device 12 cuts the polyethylene-coated copper pipes 5 in the area of the connecting means 10. The polyethylene-coated copper pipe 5 has the reference numeral 5a.

In a subsequent working step, the polyethylene-coated copper pipe Sa is inserted into a copper pipe 6. The outer diameter of the pipe 5a and the inner diameter of the pipe 6 should not be too different. To facilitate the joining of the pipes 5a and 6, the outer surface of the pipe 5a can be provided with a lubricant layer, for example an oil of paraffin type. In order not to damage the upper surface of the polyethylene layer 8 during insertion, it is suitable to break the inner edge of the end surface of the pipe 6.

After the tubes 5a and 6 have been inserted into each other, this double tube is inserted into a die 13 and the tube 6 is tightened on the tube 5a. Thereby, the polyethylene layer 8 is slightly deformed. In order to prevent the deforming forces from deforming the inner tube 5, this is supported by a mandrel 14, which by means of a mandrel rod 15 or in another known manner is held in the area of the matrix 13. The connecting tubes thus produced are reconnected by means of pipe connectors known per se and guided by an additional extrusion machine 16, which applies the polyethylene layer 9 to the casing. The connecting pipe provided with polyethylene layer 9 has the reference numeral 6a. In the area of the connecting means, the connecting pipe 6a is cut back to single lengths by means of a cutting device 17. Each single length 6a is inserted into a further copper pipe 7, whereby the same lubricant and edge breaking measures shall apply and the same diameter ratio shall prevail 6a and the tube 7 consisting of the connecting tube is inserted into a second matrix 18 and the tube 7 is tightened on the polyethylene layer 9 of the tube 6a, a mandrel 19 providing the support of the inner tube 5.

In a final working step, the individual lengths of the supply line 1 are deburred at the ends, ie the towbars are removed and the tow ends are cut off and cut to a length of, for example, 6 m.

The supply line 1 manufactured according to the method of invention is characterized by a force-bonded connection between the individual copper pipes 5, 6 and 7 and the polyethylene layers 8 and 9 and by a precisely concentric arrangement of these layers.

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Claims (6)

10 15 20 25 30 35 465 914 'PATENT CLAIMS A method of manufacturing an electrical supply line consisting of at least two mutually insulated, concentric single conductors in the form of metal pipes, in particular for electrically driven underwater pumps, characterized in that - on a first, seamlessly drawn copper pipe, a electrically insulating plastic layer, - that the coated copper pipe is inserted into a second, seamlessly drawn copper pipe with a larger inner diameter, and - that the second copper pipe is then firmly crimped onto the plastic layer on the first copper pipe. 2. A method according to claim 1, characterized in that an electrically insulating plastic layer is extruded on the second copper tube and this plastic-coated composite tube is inserted into a third metal tube, and that the metal tube is then firmly shrunk on the plastic layer on the second copper tube. A method according to claim 1 or 2, characterized in that the second and third features, respectively, are drawn for cross-sectional reduction through a drawing die, the inner tube being supported by a mandrel held in the area of the drawing die. 4. A method according to any one of claims 1 to 3, characterized in that a number of metal pipes are connected to each other at the ends and fed through an extrusion machine for applying an electrically insulating plastic layer to the pipe surface, that the pipes after plastic curing that each cut pipe is inserted into a larger diameter metal pipe and that the metal pipe is shrunk on the plastic layer, the inner pipe being supported by a mandrel, that a number of such composite pipes be connected to each other at the ends and fed through the outer pipe. an extruder which applies an additional, electrically insulating plastic layer to the second tube, that the composite tubes after the curing of this plastic layer are cut at the connection points and that each cut composite tube is inserted into a larger metal tube which shrinks on the plastic layer of the composite pipe, whereby the inner pipe is also supported here by means of a mandrel. Method according to one of Claims 1 to 4, characterized in that the metal-coated metal tube or composite tube is inserted into the relevant, larger metal tube with a small play, possibly with the aid of lubricant. Method according to one of Claims 1 to 5, characterized in that the inner edge of the outer pipe in question is broken before the insertion of the plastic-coated plastic-coated metal pipe or composite pipe is inserted.