FI64451B - ELECTRIC INSULATION ROERFOG MELLAN ETT PLASTROER OCH TVAO AVETTA OEVERLAPPADE METALLROER - Google Patents

Description

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Patent- och registerstyrelsen 'Anseiun utltgd ech utUkrHtm publicend 29.07.83 (32) (33) (31) Pursued privilege —Begird prlorltet 25.0U. 73

Austria-Österrike (AT) A 3693/73 (71) (72) Walter Schwarz, Engerthstrasse 237 B, Wien 2, Austria-Österrike (AT) (7l) Berggren Oy Ab (5M Electrically insulating pipe connection between a plastic pipe and two metal pipes fixed by it This invention relates to an electrically insulating pipe joint between a pipe of reinforced plastic and two metal pipes overlapping it, having at least one shoulder extending around the pipe, on which the end of the pipe of reinforced plastic is shouldered, on the shoulder of a pipe of reinforced plastic. gripped, wound, pressed or cast.

By reinforced plastic is meant herein a plastic that improves all of the desired properties compared to the same unreinforced plastic.

To achieve this improvement, the plastic contains reinforcing and / or filler additives, which usually consist of powders, short and continuous fibers, fluff, mats, Kars gauze and fabrics which, for example, have a multiplied modulus of elasticity, higher tensile and compressive strength, good adhesion and resistance to plastic and all its components. Such reinforcing agents are preferably glass fibers, ceramic fibers, asbestos fibers, synthetic fibers, sisal, metal bars, monocrystalline fibers and carbon fibers. Of the synthetic fibers, polyamide and polyester fibers are of particular value, which are added to the plastic as reinforcement 2 64451 as grooves, staple fibers and fabrics.

Plastics include resin-hardener combinations of polyester resins, epoxy resins, phenolic resins, melamine resins, silicone resins, hydrocarbon resins, vinyl ester resins, acrylate resins, etc., with additional modifiers and modifiers to improve certain properties.

Tubes made of reinforced plastic are already known and are used in many different areas. Due to their good mechanical and chemical properties, they have often been used alongside pipes made of other materials such as steel and iron, ceramics, concrete and glass, especially after the successful production of plastic pipes with relatively uniform good properties and sizes ranging from the largest up to diameters.

It was precisely with large diameter pipes, 1-2 m and more, that pipe connections were difficult and expensive, especially when the pipe connections also had to be made pressure-resistant.

In addition, there has so far been almost no technically and economically feasible proposal for the connection of pipes of different materials with a large nominal size.

The object from which the present invention is based is therefore, above all, to create a connection for large-diameter pipes which is not only tight but also pressure-resistant, although the proposal according to the invention is of course also available for small pipes.

It is a further object of the invention to provide a connection for pipes made of different raw materials, for example steel and plastic, and of various plastics which have no or only low affinity.

The invention further relates to the task of how a pipe joint is to be formed when it must be gas-tight, liquid-tight and pressure-resistant without mechanical accessories such as flanges, sealing plates, cages, screw-in fittings or the like.

In order to solve this problem, a pipe connection according to the definition given at the outset is suitable, which is characterized in that a plurality of annular projections and radial grooves are arranged in a stepwise manner on the ends thickened with respect to the wall of the metal pipes.

Adhesives for improving the adhesion between the reinforced plastic and the metal are known and the adhesive layer between the two pipe ends can be, for example, an epoxy resin.

It is clear that a pipe connection according to the invention in an embodiment in which two metal pipes, for example two steel pipes are connected together, occurs twice, both joints being formed symmetrically of a pipe piece of reinforced plastic against the transverse intermediate surface.

A pipe piece made of reinforced plastic, which in this case can also be called a connecting piece, because it forms a pipe connection at both ends, is made of an electrically insulating material. When two metal pipes are connected to each other, this arrangement forms an electrically insulating pipe connection.

Electrically insulating pipe connections are known per se, for example Austrian Patent Publication No. 302 7 ^ 8. As described therein, they are intentionally made to be placed in a pipeline, usually by connecting two metal lugs to a coupling piece of electrically insulating material by means of pipe joints. The outer ends of these nets are then welded to the pipeline at the construction site.

Certain embodiments of the invention provide a further improvement to a pipe joint or insulation joint, which consists of a mirror image duplication of the pipe joint and allows mass production of pipe couplings characterized by having little or no. no expansion of length at all with the greatest possible pressure resistance.

According to the invention, this object is achieved essentially in that a plurality of fixed rings and radial grooves are arranged stepwise in connection with each other on both wall-reinforced or coiled wall-reinforced metal pipe ends.

Although the pipe joint according to the invention can be manufactured in any known manner in a winding machine, a certain method of operation has proved to be particularly time-saving. In addition, it can be used to inextricably produce very strong, electrically insulating pipe connections for pipes with a large diameter, for example 1000-24000 mm.

The manufacturing method according to the invention is essentially based on the fact that the plastic pipe is cross-wound with a winding angle of less than 90 ° and in the region of the radial grooves is additionally provided with a winding angle of about 90 °.

In carrying out the method, the winding geometry to be kept within the private work steps can be included in an automatically controlled winding program in a known manner. Thus, by keeping constant other parameters that can affect the machine's winding result, it is possible to automatically produce very strong joints with only radial expansion and no longitudinal expansion and thus, after the joint is built into the pipeline, at least partially equalize the expansion oscillations .

It is expedient to proceed in such a way that each layer of plastic pipe, which always extends into two grooves equally high from the inner surface of the metal tube end, is cross-wound and only then the two grooves in the laminate shell are completely filled by winding at an angle of about 90 °. Although it is also possible, for example, in cross-linking, after each forward and return winding of the machine to be toggled to slightly fill both grooves, a faster and better result is obtained with the above method of operation. We have further found that a pipe joint with the highest strength can be made, which can withstand e.g. an internal pressure of 100 at 2000 mm with ice with 6-fold certainty when the inner and outer layers in a three-layer wound plastic pipe are wound at a flatter angle than the middle layer.

5 64451

Inside each laminate shell, the sections marked as layers may have a defined structure with the supply, return and flow windings.

Improved strengths are obtained when, within each winding layer, the forward and return windings are performed at winding angles of + 60 ° and resp. -60 ° and then the subsequent flow winding terminating the layer is carried out at an angle of about 0.6 °, i.e. as a radial winding.

However, it is also possible to construct private winding cover layers from a cross winding in which the forward winding is continuously repeated at an angle of about + 86 ° and the return winding at an angle of about -H °.

By correspondingly shaping the pipe ends, the plastic pipe can be manufactured in such a way that at least a certain winding of the winding layer is constructed between the circumferential pins by a zig-zag winding and a radial winding placed on top of this zig-zag winding.

The pipe connection according to the invention is suitable for numerous embodiments which are adapted to the specific purpose which the pipe line in each case serves. However, all embodiments share the above advantages.

Figure 1 shows an electrically insulating pipe connection formed of a pipe joint or two mirror-shaped pipe joints in partial longitudinal section. Fig. 2 shows an end view of the metal pipes connected by interconnection along the line II-II in Fig. 1 without a winding and a sealing ring, while Fig. 1 shows a longitudinal section along radial line I in Fig. 2. Fig. 3 shows a partial section

According to Figures 1 and 2, the ends 2 of the two metal pipes to be connected to each other are thickened and mirror-shaped. Each end of the tube has two annular projections 3 and three radial grooves 5, each of which preferably has a trapezoidal cross-section. In series production, it is advantageous when the cross-sections of the different radial grooves 5 are made similar to one another.

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An additional manufacturing advantage is obtained; ' at the time when the outer wall of the radial groove 5 immediately changes to the inner wall of the annular projection 3, which annular projection 3 likewise preferably has a trapezoidal cross-section.

However, the grooves 5 and the ring projections 3 can be made of a different cross-section with their straws not shown in detail in Figures 1 and 3.

Each annular projection 3 is preferably provided with radial cuts 15, which enables better power transmission in a three-axis tensioned pipe connection through a plastic pipe made of reinforced plastic. The ring projection 3 may have protrusions 19 in the radial direction, e.g. pins or pins, but also recesses, e.g. grooves, spiral, transverse or longitudinal grooves or radial and longitudinal grooves with perforated strips, as a result of which additional anchoring of different laminate layers of plastic pipe can be provided. in winding. The use of pins and pins is included in the prior art.

In a particular embodiment according to the drawing, the area between the inner surface of the plastic tube 1, preferably made in a certain way, as described in more detail below, and the closest edge surfaces of the metal tube ends 2 is filled with a seal consisting of at least one leak stop layer 8 and a prefabricated connection is coated with a protective layer 18. The connecting piece 10 may be made of any suitable material. Preferably it is a fiber-reinforced plastic. The leak stop layer 8 is constructed of windings, films, cardboard gauze, mats, fabrics and resin layers.

The end collars of the two metal tube ends 2 closest to each other may have a groove 16 in which a sealing ring 11 is placed, which is pressed against the protective layer 18 of the connecting piece 10.

The plastic tube 1 can be partially surrounded on its outer side by protective tubes 9, which in particular cover the area of the radial grooves. In the area of the protective tubes and on the same surface as their outer surface, there may be a protective layer 14 of soft elastic and electrically insulating castings val33 S 3.3. ·

Finally, the entire pipe connection is provided with a layer (not shown) wrapped with insulating tape and with a covering groove on the outer surface of the pipe.

Figure 3 shows in longitudinal section a part of the performance filter as a reduction piece when moving from a larger pipe to a smaller one, in which embodiment the pipe end 2 with the larger inner diameter is thickened towards the pipe axis and the smaller pipe end is thickened away from the pipe axis.

The reinforced plastic tube 1 can be wound in any known manner, after both metal tube ends 2 and a seal consisting of a prefabricated connecting piece 10 on which a protective layer 18 and a leakage preventing layer 8 are placed are placed in a receiving device of a winding machine (not shown).

It may be advantageous to first provide the winding cover layer with an adhesive layer, whereby the adhesive may be the same resin or a combination of several resins compatible with each other with which the reinforcing fibers of the plastic tube are bonded.

As already mentioned above, winding with reinforcing fibers impregnated with a thermoplastic resin and having a volume fraction of the plastic tube, calculated as resin-free, preferably of more than 60% by volume, is carried out with only circumferential expansion but no axial expansion in the pipe joint shown in the drawings. when the pipe joint is subjected to internal pressure caused by the fluid flowing through it.

Radial, axial and tangential stresses are present in the pressurized pipe section. To receive these forces, the fibers are wound on the winding layers in a specified orientation. In this case, with the given winding geometry used, the plastic tube has a certain fibrous structure, preferably in the form of an isotensoid, which enables these stresses to be received as tensile forces, whereby most preferably all fibers reach their strength limits simultaneously;

According to a particularly valuable embodiment, the individual layers are wound in crosslinks at different winding angles, whereby it is possible to achieve a particularly high puncture strength in addition to good bending strength. In an artificial tube wound with three laminate shells,

In the plastic pipe, the reception of radially outward pressure forces can be further improved by placing radially wound layers, about 5-10% of this wall thickness, immediately on top of the leak stop layer 8, calculated on the total wall thickness of the plastic pipe. the second laminate layer and finally most of the top laminate layer are cross-wound, whereby radially wound layers of 2-5% strength are again placed as the top layer and to complete the top laminate shell.

In addition to the preferred method of manufacturing the pipe joint according to the invention by a certain winding method of a plastic pipe, other winding methods connecting unidirectional grooves or reed fabrics to the circumferential layers are possible depending on the nominal pipe size, pressure requirement and the nature and interaction of all loads.

It is to be understood that all of the described private features may be used in arbitrary combinations to form numerous other embodiments of the invention. In particular, insulating pipe joints of the aforementioned quality are within the scope of the invention, in which the embodiments according to the invention are implemented in pairs.

The raw materials mentioned in this description, of which the pipes connected to each other in accordance with the invention may consist, are mentioned by way of example only and it is to be understood that any other known or as yet unknown raw materials may be present instead. Thus, for example, boron fibers can be used in the reinforcement layers, which are known to be made by condensing boron vapor on an extremely thin tungsten wire and have a very high modulus of elasticity. In order for the embodiment of the pipe joint according to the invention to be best suited to the intended use, it is of course also possible to use as a raw material a plastic with various reinforcing agents in suitable percentages.

9 '64451 coated with a protective layer 18. The connecting piece 10 may be made of any suitable material. Preferably it is a fiber-reinforced active ingredient. The leak stop layer 8 is constructed of windings, films, cardboard gauze, mats, fabrics and resin layers.

The end faces of the two metal pipe ends 2 closest to each other may have a groove 16 in which a sealing ring 11 is placed, which is pressed against the protective layer 18 of the connecting piece 10.

The active material tube 1 may be partially surrounded on its outer side by a protective tube 9, which in particular covers the area of the radial grooves. In the region of the protective tubes and on the same surface as their outer surface, there may be a protective layer 14 of soft-elastic and electrically insulating casting compound.

Finally, the entire pipe joint is provided with a layer (not shown) wrapped with insulating tape and with a cover sheet on the outer surface of the pipe.

Fig. 9 shows a longitudinal section of a part of the embodiment when moving from a larger pipe to a smaller one, in which embodiment the thickening of the pipe end 2 with the larger inner diameter takes place towards the pipe axis and the smaller pipe end thickens away from the pipe axis.

The reinforced synthetic pipe 1 can be wound in any known manner, after both metal pipe ends 2 and a seal consisting of a prefabricated connecting piece 10 on which a protective layer 18 and a leakage preventing layer 8 are placed are placed in a receiving device of a winding machine (not shown).

It may be advantageous to first provide the winding cover layer with an adhesive layer, in which case the adhesive may be the same resin or a combination of several resins compatible with each other, with which the reinforcing fibers of the artificial tube are bonded.

As mentioned above, the winding of reinforcing fibers impregnated with a thermoplastic resin and having a volume fraction of the synthetic pressure tube, calculated as resin-free, is preferably more than 60% by volume. , is performed in such a way that in the pipe joint shown in the drawings 10 64451 only a circumferential expansion occurs, but not an axial expansion in addition, when the pipe joint is subjected to the internal pressure caused by the fluid flowing through it.

Radial, axial and tangential stresses are present in the pressurized pipe section. To receive these forces, the fibers are wound on the winding layers in a specified orientation. In this case, the specific winding geometry used gives the synthetic tube a specific fibrous structure, preferably in the form of an isotensoid, which allows these stresses to be received as tensile forces, in which case, in the most preferred case, all fibers reach their strength limits simultaneously.

According to a particularly valuable embodiment, the individual layers are wound in crosslinks at different winding angles, whereby it is possible to achieve a particularly high puncture strength in addition to good bending strength. In an artificial tube wound with three laminate shells,

The reception of radially outward compressive forces in the synthetic pipe can be further improved by placing radially wounded layers on top of the inner laminate layer, based on the total wall thickness of the synthetic pipe, immediately on top of the leakage stop layer 8, about 5-10% of this wall thickness. the second laminate layer and finally most of the top laminate layer are cross-wound, whereby radially wound layers of 2-5% strength are again placed as the top layer and to complete the top laminate shell.

In addition to the preferred method of manufacturing the pipe joint according to the invention with a certain winding method of the synthetic pipe, other winding methods connecting unidirectional grooves or reed fabrics to the circumferential layers are possible depending on the nominal pipe size, pressure requirement and the nature and interaction of all loads.

It is to be understood that all of the described private features may be used in arbitrary combinations to form numerous other embodiments of the invention. In particular, insulating pipe joints of the above-mentioned quality are within the scope of the invention, in which the embodiments according to the invention are implemented in pairs.

The raw materials mentioned in this description, of which the pipes connected to each other in accordance with the invention may consist, are mentioned by way of example only and it is to be understood that any other known or as yet unknown raw materials may be present instead. Thus, for example, boron fibers can be used in the reinforcement layers, which are known to be made by condensing boron vapor on an extremely thin tungsten wire and have a very high modulus of elasticity. In order for the embodiment of the pipe joint according to the invention to be optimally suited to the intended use, it is of course also possible to use as raw material an active substance in which the various reinforcing agents are present in suitable percentages. In the case where the pipe connection according to the invention has to be used to connect synthetic pipes, it is advantageous that it is thus possible to use equipment known per se and simply made of fiber-reinforced synthetic material, which has extreme strength compared to other synthetic materials, e.g. PVC. thin wall thicknesses and thus low weight with high dimensional accuracy and puncture resistance.

Claims (11)

12 64451 Claims' An electrically insulating pipe joint between a reinforced plastic pipe and two metal pipes overlapping it, having at least one shoulder extending around the pipe, on which the end of the reinforced plastic pipe (1) is wound, compressed or molded, characterized in that: a plurality of annular projections (3) and radial grooves (5) are arranged in a stepped manner on the ends (2) thickened with respect to the wall of the metal tubes · Pipe connection according to Claim 1, characterized in that there are three ring projections (3) and radial grooves (3). Pipe connection according to Claim 1 or 2, characterized in that each radial groove (5) has a trapezoidal cross-section. Pipe connection according to Claim 1, 2 or 3, characterized in that the outer wall of the radial groove (5) having a trapezoidal cross-section immediately extends into an annular projection (3) which also has a trapezoidal cross-section. Pipe connection according to Claims 1, 2 and 3, characterized in that each annular projection (3) has radial grooves (15). Pipe connection according to Claim 1, 2, 4 or 5, characterized in that the annular projection (3) has projections (19). Pipe connection according to one of Claims 1 to 6, characterized in that the depth of each radial groove (5) measured from the outer edge of the adjacent ring projection (3) is approximately equal to the difference between the outer edges of the two adjacent ring projections (3). Pipe connection according to one of Claims 1 to 4 and 7, characterized in that the upper surface of the wound plastic pipe (1) is covered by a protective pipe (9) in the region of at least one, preferably all, radial grooves 13 644 51 (2) of each metal pipe end. Pipe connection according to Claim 8, characterized in that the plastic pipe (1) has a protective layer (14) of soft-elastic casting in the region between the two protective pipes (9). Pipe fittings according to one of Claims 1 to 9, characterized in that the area between the inner surface of the metal pipe ends (2), the inner surface of the plastic pipe (1) and the closest edge surfaces of the metal pipe ends (2) is filled with a leak stop layer (8). ) and a prefabricated connector (10) coated with a protective layer (18). Pipe connection according to Claim 9, characterized in that each of the closest edge surfaces of the metal pipe end (2) has a groove (16) with a sealing ring (11) which presses against the protective layer (18) of the connecting piece (10). 14 64451