JPH07353B2 - Method of manufacturing a power supply conduit consisting of at least two concentric metal tubes insulated from each other - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention comprises at least two mutually insulated concentric metal tubes, in particular for electrically driven submersible pumps; Of the first metal tube is inserted into the second outer metal tube, and the second outer metal tube is fused onto the inner first metal tube by a drawing die.

BACKGROUND OF THE INVENTION A power supply conduit has been proposed which consists of three concentric metal tubes electrically insulated by a synthetic resin layer for the supply of electrical energy and a coolant or lubricant to a submersible pump. Three
The two concentric tubes form a three-phase conductor for the supply of electrical energy to the submersible pump, while the inner space of the inner tube serves as a supply duct for the coolant or lubricant. This feed conduit is inserted inside a somewhat larger diameter pipe, the space between the feed conduit and the larger diameter pipe having a ring-shaped cross section serving as a coolant or lubricant return duct.

This kind of power supply conduit is subject to a series of requirements which heretofore could not be solved with complete sufficiency. Since this feed conduit is intended for rigid tubing, this tubing must be connected to extend its length depending on the point of use. Moreover, the position of the tubes must always be the same at least at the end of each individual feed conduit section in order to achieve an electrical connection of the individual feed conduit sections without problems. In order to avoid axial movement of the individual power supply conduit sections during the electrical connection work and also after the installation of the power supply conduit, it is usually arranged in a vertical position in one power supply conduit-friction between the metal tube and the plastic. Coupling is required.

SUMMARY OF THE INVENTION The present invention allows for economical processing of tubes and dimensional retention with respect to tube position and wall thickness and ensures frictional engagement between individual tubes through electrically insulating layers. The object of the invention is to provide a method for manufacturing a rigid pipe system.

SUMMARY OF THE INVENTION The object of the invention is to provide at least two mutually isolated elements as claimed in claim 1, in particular for electrically driven submersible pumps. Consists of concentric metal tubes, wherein the inner first metal tube is fitted into the outer second metal tube and the outer second metal tube is fused onto the inner first metal tube by means of a drawing die. In the method for manufacturing a power supply conduit, the inner first metal pipe is coated with a synthetic resin layer on the outer periphery thereof before the outer second metal pipe is fitted onto the inner first metal pipe. And before fitting the outer second metal tube onto the inner first metal tube, the inner first metal tube is coated on its outer periphery with a synthetic resin layer by extrusion. Characteristic,
This is solved by the method of manufacturing the power supply conduit.

The fitting of the second metal tube by cold drawing may be performed. The reason is that the synthetic resin layer is not damaged by high temperature. It is also important that the synthetic resin layer be slightly deformed, which results in a tight bond between the two metal tubes.

According to a particularly advantageous design according to the invention, after fitting the second metal tube, the second metal tube is likewise coated with a synthetic resin and the composite tube thus produced is fitted into the third metal tube, and A third metal tube is bonded onto the synthetic resin layer of the second metal tube.
In this way, the object provided with three electrically insulated metal tubes as electrical conductors is obtained.

The coalescence is carried out in an advantageous manner by drawing the tube through a drawing die, the mandrel in the region of the drawing die supporting the inner tube inwardly during the coalescence. The mandrel helps prevent deformation of the inner tube, as a large amount of force is required to achieve a frictional bond between the coalesced tubes and the synthetic resin layer.

The synthetic resin layer is coated in an advantageous manner by extrusion in order to obtain a uniform thickness of the synthetic resin layer between the tubes. A particularly economical processing is achieved when a plurality of metal tubes are joined together at their end faces and conveyed, the extruder coating a synthetic resin layer on the tube surface. After cooling or hardening of the synthetic resin, the tubes are separated at the connection points and each individual tube is fitted into a metal tube of larger diameter, the metal tubes being fused onto the synthetic resin layer, the inner layer being Inwardly supported by a mandrel. Such connecting pipes are connected to each other at their end faces and conveyed, and the extruder forms a synthetic resin layer on the second metal pipe. After cooling or hardening of this synthetic resin layer, the connecting pipes are separated at the connecting points, and the individual connecting pipes are fitted into the metal pipes which are bonded onto the synthetic resin layer, the inner pipe being supported by the mandrel. It

The metal pipes or connecting pipes coated with synthetic resin are inserted with little play, if necessary with the addition of lubricating oil. A play or diameter difference of approximately 1 mm is preferred. The surface of the synthetic resin layer is reasonably lubricated to improve the slippage,
The inner edge of each outer tube, which is preferably paraffin oil-coated, is chamfered prior to insertion of the synthetic resin-coated metal tube or connecting tube so that the synthetic resin layer is not damaged during insertion.

(Example) The present invention will be described in detail based on an illustrated example.

The feed conduit 1 is arranged vertically inside the tube 2. A duct 3 is used for supplying a coolant or a lubricant to a submersible pump (not shown), while a space 4 having a ring-shaped cross section between the power supply conduit 1 and the pipe 2 is provided for returning the coolant or the lubricant. used.

The power supply conduit 1 comprises three concentric copper tubes 5, 6 and 7 as conductors for the supply of electrical energy to a submersible pump, between which electrical power is provided by synthetic resin layers 8 and 9 preferably made of polyethylene. Electrically isolated. Copper tubes 5, 6
And 7 carry three-phase rotating currents. The copper tubes 5, 6 and 7 and the polyethylene layers 8 and 9 frictionally engage each other, so that axial movement of the copper tubes 5, 6 and 7 is avoided even in the vertical arrangement. Seamless drawn tubes are used for the copper tubes 5, 6 and 7.

The inner pipe 5 is, for example, 19x1.5 mm, that is, outer diameter 19 mm, wall thickness 1.5 mm
Is. Polyethylene layer 8 that touches the tube and the mirror
Has a wall thickness of 1.5 mm. The middle copper tube 6 is 25mm x 1.5mm,
That is, the outer diameter is 25 mm and the wall thickness is 1.5 mm. The polyethylene layer 9 in contact with the boundary has a wall thickness of 1.5 mm. The outer copper tube 7 has a size of 31 × 1.5 mm, that is, an outer diameter of 31 mm and a wall thickness of 1.5 mm. For the above dimensions, the wall thickness of the copper tubes 5, 6 and 7 can be reduced from the inner one to the outer one, but the cross sections of the copper tubes 5, 6 and 7 are the same. In some cases, it may be advantageous to coat the copper tube 7 with another synthetic resin layer.

For the production of the power supply conduit 1, firstly a plurality of copper tubes 5 are connected to one another at connection points 10 known per se and are usually guided through an extruder 11 which forms a polyethylene layer 8 on the copper tubes 5. The pipe 5a is separated by the separation device 12 at the connection point 10.

In the next processing step, the polyethylene-layered conduit 5a is fitted into the copper tube 6. To facilitate the joining of tubes 5a and 6, the outer surface of tubes 5a can be coated with a lubricant, such as paraffin oil. The inner edge of the end face of the tube 6 should be chamfered so that the surface of the polyethylene layer 8 is not damaged during insertion.

After the tubes 5a and 6 have moved relative to each other, the tube 6 fits snugly onto the tube 5a. The polyethylene layer 8 is then slightly deformed. In order to prevent the inner tube 5 from being deformed by the deformation force, the inner tube 5 is supported by a mandrel 14 in the area of the drawing die 13 in the mandrel 15 or other known manner. The connecting pipes are connected to each other by connecting points known per se and the extruder 16 coats the polyethylene layer 9. The tube with the polyethylene layer 9 is designated by 6a.

At the connecting point, the separating device 17 divides the connecting pipe 6a into individual lengths. Each individual tube 6a is introduced into another copper tube 7 and the same measures should be taken when joining tubes 5a and 6 with the addition of lubricating oil, chamfering or selection of the diameter ratio.
The connecting pipe consisting of the pipe 6a and the pipe 7 is introduced into another drawing die 18, the pipe 7 is tightly fitted on the polyethylene layer 9 of the pipe 6a, and the mandrel 19 supports the inner pipe 5.

In the subsequent processing, the individual lengths of the power supply conduit 1 are realigned on the end faces, i.e. the drawing flash is removed and the extraction end is cut, for example to a length of 6 m.

The power supply conduit 1 produced by the method according to the invention is characterized by the frictional engagement of the individual copper tubes 5, 6 and 7 with the polyethylene layers 8 and 9 and the precisely concentric arrangement of these layers.

[Brief description of drawings]

FIG. 1 is a power supply conduit in an assembled state, and FIGS.
FIG. 5 is a diagram showing a manufacturing process of the power supply conduit. Reference numeral 5 ... Copper tube 6 ... Copper tube 7 ... Copper tube 8 ... Polyethylene layer 9 ... Polyethylene layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Franz-Josef Holtorf Federal Republic of Germany Osnaburiyutsk Amed Wingstrasse 51 (56) References JP-A-51-105964 (JP, A) JP-A-SHO 52-133586 (JP, A) JP-B-45-22036 (JP, B1) JP-B-44-13057 (JP, B1)

Claims (4)

[Claims] 1. At least two mutually insulated concentric metal tubes, wherein an inner first metal tube is fitted into an outer second metal tube and an outer second metal tube is provided by a drawing die. A method for manufacturing a power supply conduit for an electrically driven submersible pump, which is fused onto an inner first metal tube, comprising: an outer second onto the inner first metal tube (5). Metal tube (6)
A method for manufacturing a power supply conduit, characterized in that the inner first metal tube (5) is covered with a synthetic resin layer (8) on its outer periphery by extrusion molding before the fitting. 2. After fusion of the outer second metal tube (6), the outer second metal tube (6) is likewise coated with a synthetic resin layer (9) and is produced in this way. The connecting pipe is fitted into the third metal pipe (7), and the third metal pipe (7) is attached onto the synthetic resin layer (9) of the outer second metal pipe (6).
The method according to claim 1. 3. A large number of metal pipes (5) are connected to each other at their end faces and conveyed, a synthetic resin layer (8) is coated on the surface of the metal pipe by extrusion molding, and after the synthetic resin is hardened, each metal pipe is formed. (5) is separated at the connection point (10) and each individual pipe (5a)
Is fitted into a metal tube (6) of larger diameter, the metal tube (6) being glued onto the synthetic resin layer (8), the metal tube (5) being supported on its inner side by a mandrel (14). The plurality of pipes are connected to each other at their end faces and conveyed, and another extruder (16) coats another synthetic resin layer (9) on the outer second metal pipe (6), Each tube (6a) separated at the connection point after curing of the synthetic resin layer (9) is fitted into a metal tube (7) of larger diameter which is fused onto the synthetic resin layer (9), 3. A method according to claim 1 or 2, characterized in that the inner tube is supported on its inner side by a mandrel (19). 4. The inner edge of each outer pipe (6) is chamfered before fitting a synthetic resin-coated metal pipe (5) or composite pipe.
A method according to any one of claims 1 to 3.