CN116615620A - Connection element system for establishing a pipe connection, pipe connection comprising such a connection element system and method for establishing such a pipe connection - Google Patents

Abstract

The invention relates to a connection element system (1) for establishing a tube connection (11) between a connection element (2) and a plastic tube, a plastic composite tube or a metal plastic composite tube, the connection element system (1) comprising a connection element (2) fitted with a compression sleeve (3), and the compression sleeve (3), the connection element (2) comprising at least one support body (6) provided with a plurality of circumferential outer ribs (5, 5a, 5b, 5 c) for pushing up a tube end (7), wherein the connection element system (1) according to the invention is characterized in that the connection element system (1) further comprises a retaining element (4), the retaining element (4) being interengaged with the connection element (2) and the compression sleeve (3). The invention also relates to a pipe connection (11) between a pipe end (7) of a plastic pipe, a plastic composite pipe or a metal plastic composite pipe and a connecting element (2) comprising a connecting element system (1) according to the invention and to a method for establishing a pipe connection (11) according to the invention.

Description

Connection element system for establishing a pipe connection, pipe connection comprising such a connection element system and method for establishing such a pipe connection

Technical Field

The invention relates to a connecting element system for establishing a riser connection between a connecting element and a plastic pipe, a plastic composite pipe or a metal plastic composite pipe, comprising a connecting element fitted with a compression sleeve, and a compression sleeve, the connecting element comprising at least one support body provided with a plurality of circumferential outer ribs for pushing up the pipe ends. The invention also relates to a pipe connection comprising such a system of connecting elements, and to a method of establishing such a pipe connection.

Background

Connection elements for double-set connections and pipe connections comprising such connection elements are known from the prior art, for example from DE 10 2016 117 480 A1. A tube connection is disclosed which comprises a support body, an inner sleeve or extrusion sleeve and an axially pushed-up outer sleeve. In order to bring the compression yoke of the compression tool required for pushing the jacket against the compression sleeve, the compression sleeve has a compression flange which is of one-piece construction with the compression sleeve. This gives the press jacket uneven radial deformation after pushing on the jacket. This in turn results in a greater displacement inclination of the jacket during installation of such pipe connections in the pipe system, which requires additional fastening of the jacket to the support body. In addition, uneven radial deformation of the jacket deteriorates the sealing performance of such pipe connections. Furthermore, the press jacket is rigidly fastened to the support body. The rigid connection makes it difficult for the tube ends to be pushed into the accommodation space between the support body and the inner sleeve. This is especially the case when the pipe ends are constructed in an extremely oval shape, which may be the case especially after severing the pipe connection, or when there is a significant eccentricity of the pipe.

Disclosure of Invention

Against this background, it is an object of the present invention to provide a connection element system for a riser connection, which connection element system overcomes the disadvantages of the prior art. In particular, the connecting element system according to the invention causes a long-term sealed pipe connection in the pipe connection formed thereby. Furthermore, in particular in the case of extreme ellipses or eccentricities, the pipe ends should be able to be easily pushed between the support body and the pressing or inner jacket.

This and other objects are achieved according to the invention by a connection element system for riser connection having the features of claim 1, by a pipe connection having the features of claim 6 and by a method for riser connection having the features of claim 10. Preferred embodiments of the connecting element system according to the invention, the pipe connection according to the invention and the method according to the invention are described in the dependent claims, respectively.

In contrast to the rigid locking methods of the prior art, the invention proposes a flexible connection between the compression sleeve and the connecting element by means of a retaining element as a separate component, which engages with the connecting element and the compression sleeve. The compression sleeve is thereby preassembled on the connecting element, which simplifies the production of the tube connection. Since the press jacket is constructed as a separate component which is not in contact with the medium flowing through the pipe connection according to the invention at any point during use of the pipe connection according to the invention, a more cost-effective and/or less chemically resistant material can be used as material for the press jacket. By using the holding element as a separate component, the compression sleeve has a certain mobility with respect to the central axis of the connecting element. This simplifies the insertability of the tube, since possible tube eccentricities can be compensated for. In addition to providing better sealing throughout the length of the support, the movability of the compression sleeve relative to the central axis also places the compression sleeve and the outer sleeve in equilibrium, thereby preventing axial relative movement of the outer sleeve.

The invention therefore provides a connection element system for establishing a riser connection between a connection element and a plastic pipe, a plastic composite pipe or a metal plastic composite pipe, the connection element system comprising a connection element fitted with a compression sleeve, and a compression sleeve, the connection element comprising at least one support body provided with a plurality of circumferential outer ribs for pushing up the pipe ends, wherein the connection element system according to the invention is characterized in that the connection element system further comprises a retaining element, which retaining element interengages with the connection element and the compression sleeve. The invention also provides a pipe connection between a pipe end of a plastic pipe, a plastic composite pipe or a metal plastic composite pipe and a connecting element, wherein the pipe connection comprises: the end part of the plastic pipe, the plastic composite pipe or the metal plastic composite pipe; the connecting element system according to the invention, wherein the support body of the connecting element is introduced into the tube end; a compression sleeve and an outer sleeve mounted to the compression sleeve to secure the tube ends to the support body of the connection element. Finally, the invention also relates to a method for establishing a pipe connection according to the invention, wherein the method comprises the following steps: pushing the outer sleeve onto the plastic pipe, the plastic composite pipe or the metal plastic composite pipe; introducing a support body of the connecting element into the tube end; and axially pushing the jacket over the tube end of the support body in which the connecting element is inserted.

As used herein, the term "fitting the connecting element with the compression sleeve" means pre-fixing or pre-mounting the compression sleeve on the connecting element, whereby the worker only has to hold the component in his hand at the installation site.

With the connecting element system according to the invention, it may be advantageous if the connecting element has an engagement groove and the holding element has at least one connecting element-side engagement element which engages into the engagement groove of the connecting element. The engagement element on the connecting element side of the holding element can move unimpeded into the engagement groove even during the pressing operation. Due to the circular shape of the connecting element and the holding element, even a small entry depth of the engaging element on the connecting element side in the engaging groove is sufficient, whereby a simple assembly is ensured. It may also be advantageous for the engagement groove to be formed in a raised portion on the connecting element, which raised portion forms an axial termination of the support body. Thus, the engagement groove can be integrated into the connecting element in a simple manner.

It has also proved to be advantageous if the holding element has a press-sleeve-side engagement element which engages with one another in the co-operating receptacle of the press sleeve. In the preassembled state of the connecting element system according to the invention, the compression sleeve is thereby connected to the connecting element via the retaining element in a relatively movable manner. This makes a decisive contribution to the easy introduction of the pipe ends even in the event of severe pipe ends being eccentric, thereby simplifying the installation of the pipe connection.

It is also advantageous if the connecting-element-side engagement element is formed as a plurality of individual elements arranged along the inner circumference of the holding element. Each element is preferably configured as a single spring element. Thereby, the engagement element on the side of the connection element engages resiliently on the connection element, which gives the connection a certain flexibility. This also enables a simpler assembly of the connecting element system according to the invention. Furthermore, the design with the spring element enables a defined movability of the holding element and the inner sleeve. Finally, the spring element also makes it possible to better compensate for possible manufacturing fluctuations by means of the connecting element system according to the invention.

It is also advantageous if the engagement groove of the connecting element has a groove slope. By means of such a groove slope, it is possible to avoid the holding element being pushed too far onto the connecting element during assembly. Furthermore, the groove inclination makes it possible to prevent the holding element from being pushed away from the support body even during operation, since, during radial compression of the inner sleeve or, for example, during operation, due to thermal expansion, a change in the length of the inner sleeve can occur, which can affect the holding element.

It is also advantageous if the compression sleeve is composed of an elastically deformable polymer material. Thereby further improving the stability of the pipe connection according to the invention.

In a preferred embodiment of the invention, the connecting element system according to the invention further comprises an outer sleeve for fastening the compression sleeve on the support body of the connecting element. The press sleeve is fastened to the support body by means of the outer sleeve and the pipe ends are pressed into the circumferential outer ribs of the support body. The tightness of the pipe connection according to the invention is thereby ensured. Furthermore, the press sleeve is pressed in the direction of the support body, so that the press sleeve loses contact with the holding element and no longer contacts the holding element in the completed pipe connection according to the invention.

It will be appreciated that where there are a plurality of supports on the connecting element, each support of the connecting element may be assigned a squeeze jacket which is indirectly connected to the connecting element via the retaining element. In a preferred embodiment of the invention, each support body of the connecting element is connected to the compression sleeve via a holding element according to the invention.

With regard to the pipe connection according to the invention, it is advantageous if the holding element is not in contact with the press jacket and/or the outer jacket. The holding element can thus use any suitable material, in particular a material which accompanies a chemical reaction when in contact with the press jacket and/or with the outer jacket during connection of the tube according to the invention.

In a preferred embodiment of the pipe connection according to the invention, the contactless connection between the jacket and the holding element is advantageous if the side of the engagement element facing away from the support body on the press jacket side extends at least in sections essentially parallel to the introduction slope of the jacket.

It is also preferred that the outer jacket is configured for axially sliding up the sliding sleeve of the compression jacket. The resulting slip joint is highly airtight and has a high degree of joint reliability. Sliding the sliding sleeve over the compression sleeve causes expansion of the sliding sleeve, whereby the sliding sleeve applies a radially inwardly directed force to the compression sleeve. This force is transmitted to the tube, pressing the tube against the support body provided with the surrounding outer rib, thereby forming a permanently tight connection between the tube and the connecting element. Preferably, the extrusion coating comprises at least one cylindrical section. The cylindrical section causes a reduction in the inclination of the press jacket with respect to the axial relative movement (for example due to temperature change stresses). The at least one cylindrical section preferably extends overall over a large part of the length of the press jacket, preferably over at least 60% of the length of the press jacket, particularly preferably over at least 75% of the length of the press jacket. Alternatively or additionally, the compression sleeve may comprise axial slits and/or contours by which the ring stiffness of the compression sleeve is reduced and sliding the sliding sleeve up the compression sleeve is facilitated and the force transmission of the sliding sleeve onto the tube end is also improved. The press sleeve may have an inner surface structure or contour on its inner surface, which is adapted to prevent possible axial relative movements of the press sleeve on the tube, for example due to temperature change stresses. The outer surface of the compression sleeve may also have a surface structure or profile which is adapted to prevent possible axial relative movement of the jacket, for example due to temperature variations. Alternatively or additionally, the outer surface of the compression sleeve may have a surface structure or surface profile adapted to improve the pushability of the outer sleeve (e.g. reduction of compression forces, reduction of noise during establishment of the connection). In order to achieve this surface property, the inner surface of the jacket and/or the outer surface of the extrusion jacket may have an average roughness value Ra in the range of 1 μm up to half the average wall thickness of the jacket and/or an average roughness depth Rz in the range of 5 μm up to half the average wall thickness of the jacket and/or a plurality of visible irregularities, the depth of which should not exceed half the average wall thickness of the jacket. The term "average roughness value" or "average roughness" of a surface (indicated by the symbolization "Ra") as used herein means the arithmetic average of the numerical deviations of all measurement points on the surface from the center line of the surface, and the term "average roughness depth" of the surface (indicated by the symbolization "Rz") as used herein means the roughness depth according to DIN EN ISO 4287/4288. For the surface properties of the inner and outer surfaces of the extrusion sleeve and the inner surface of the outer jacket reference should be made to DE 10 2015 122 345 A1, which is explicitly referred to. The press jacket can also comprise at its outer side, for example, at least one rib, in particular triangular or rectangular. In addition to this, the outer surface of the compression sleeve may be provided with a coating in order to improve the sliding-on properties of the sliding sleeve (e.g. reduction of compression forces, reduction of noise during establishment of the connection).

It is also advantageous that the tube ends have an inner diameter that is substantially equal to or widened from the conventional inner diameter (i.e., the inner diameter that the tube has over substantially its entire tube length after extrusion). But preferably the tube ends have a diameter that is substantially equal compared to the conventional inner diameter of the tube. As used herein, the term "substantially equal inner diameter compared to conventional inner diameter" means that the inner diameter of the tube end is not widened by a separate expansion process using a so-called expansion tool. It is very convenient here for the inner diameter of the tube end to be slightly increased, for example by a maximum of approximately 5%, relative to the conventional inner diameter by the insertion of the support body of the connecting element or for the tube end to be compressed in the tube connection according to the invention by the action of the sliding sleeve on the axial slide, so that the inner diameter of the tube end is slightly reduced, for example by a maximum of approximately 10%, relative to the conventional inner diameter. In the case of a pipe connection according to the invention, the pipe ends of which have an inner diameter that is substantially equal to the conventional inner diameter, the production process thereof is significantly simplified, since the step of expanding the pipe ends is dispensed with. If the pipe end has a widened inner diameter compared to the conventional inner diameter, the pipe connection according to the invention has a better tightness and connection reliability due to the memory of the pipe material.

Preferred materials for the connecting element according to the invention are polymeric materials such as polypropylene and glass-fibre reinforced polypropylene, polyamide and glass-fibre reinforced polyamide; heat resistant thermoplastics such as polyphenylene sulfone (PPSU), polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PSU), polyphenylene sulfide (PPS), acrylonitrile butadiene styrene copolymer (ABS), polyoxymethylene (POM) and polyester carbonate (PESC) and copolymers and blends of these polymers, wherein these polymeric materials may also be fiber reinforced, in particular glass fiber reinforced; and metallic materials, such as brass, in particularTin zinc cast bronze and stainless steel. Heat-resistant thermoplastics, such as, in particular, polyphenylene sulfone and polyvinylidene fluoride, are particularly preferred for producing the connecting element according to the invention. As used hereinThe term "heat resistant thermoplastic" is used to refer to the heat distortion resistance and heat stability of the material set and to the thermoplastic polymer material having a heat distortion resistance at a temperature of at least 150 ℃. The upper temperature limit at which such heat resistant plastics can be used is related to the materials used, wherein the upper limit of availability of such polymeric materials is 260 ℃.

According to the invention, use is made of all-plastic tubes preferably composed of polyethylene (PE, in particular PE 100 and PE-RT (polyethylene with higher heat resistance)), crosslinked polyethylene (PE-X, in particular PE-Xa, PE-Xb and PE-Xc), polypropylene (in particular atactic polypropylene PP-R) and Polybutene (PB); and plastic composite pipes and metal plastic composite pipes (MKV-pipes) preferably having a layer composed of polyethylene (PE, in particular PE 100 and PE-RT), crosslinked polyethylene (PE-X, in particular PE-Xa, PE-Xb and PE-Xc), polypropylene (in particular atactic polypropylene PP-R) and/or Polybutylene (PB) are used as plastic pipes. A layer composed of an ethylene-vinyl alcohol copolymer (EVOH) may additionally be present as an oxygen barrier layer. The metal plastic composite pipe (MKV-pipe) according to the invention preferably comprises a layer consisting of polyethylene (PE, in particular PE 100 and PE-RT), crosslinked polyethylene (PE-X, in particular PE-Xa, PE-Xb and PE-Xc), polypropylene (in particular atactic polypropylene PP-R) and/or Polybutylene (PB) and at least one layer consisting of metal, preferably aluminum. The metal layers are preferably butt welded. In the case of plastic composite pipes and MKV pipes, adhesion promoter layers may be introduced between the individual layers. According to the invention, all the tubes of the tube connection according to the invention may be identically constructed or one or more of the tubes may have different tube structures. Furthermore, the tube according to the invention may also be fibre-reinforced. The fiber reinforcement of the pipe may be present in a single or all of the pipe, over the entire pipe length or only locally. With regard to the pipe-connected plastic pipe or metal-plastic composite pipe according to the invention, it is particularly preferred that at least one layer of the respective pipe comprises crosslinked polyethylene (in particular PE-Xa, PE-Xb and PE-Xc). The material "crosslinked polyethylene" is a material having shape memory or so-called "memory effect". The memory effect is that the crosslinked polyethylene tries to return again to its original shape after its outer geometry has changed. When expanding a tube, this causes the tube comprising PE-X to try again after expansion to reach the tube inner diameter before expansion. Since the support body of the connecting element is inserted into the expanded pipe end after expansion, the memory effect when using a pipe comprising at least one layer with crosslinked polyethylene causes a particularly high tightness of the pipe connection according to the invention.

The connecting element may be a threaded molding or an unthreaded molding, i.e. an unthreaded connecting element. This includes, in particular, couplings without threads, coupling angles, multiple distributors, tees, wall angles, system transitions, angled transitions, respectively. The term "thread molding" thus relates to a connecting element having at least one thread molding. This includes, in particular, couplings, coupling angles, multiple distributors, tees, wall angles, system transitions, transitions and angled transitions, each having at least one internal thread and/or external thread.

According to the invention, the material described for the connecting element of the pipe connection according to the invention is preferably suitable as material for the holding element, the outer jacket and/or the compression jacket. Heat-resistant plastics, in particular polyphenylsulfone, polyvinylidene fluoride, polypropylene, polyamide (PA) and Polyoxymethylene (POM), are particularly preferred as materials for the outer jacket and/or extrusion jacket. Crosslinked polyethylenes (in particular PE-Xa, PE-Xb and PE-Xc) are also particularly preferred as materials for the outer jacket and/or the extrusion jacket. For the holding element, materials with a higher stiffness, such as polyoxymethylene, in particular with glass fibers, are particularly preferred; polyamides, in particular with glass fibers; polypropylene with glass fibers; polyvinylidene fluoride (PVDF); polyphenylsulfone (PPSU), and the like.

It is particularly preferred that the material of the connecting element has a higher stiffness than the material of the extrusion sleeve, the outer jacket and the tube. It is also preferred that the material of the extrusion coating has a higher stiffness than the material of the outer coating and the tube. It is also preferred that the material of the jacket has a higher stiffness than the material of the tube.

With the method according to the invention for establishing a pipe connection, it is preferred that the press sleeve is pressed onto the pipe end while the jacket is pushed axially onto the pipe end, so that the joint element on the press sleeve side has no contact point with the press sleeve. The jacket is pushed axially onto the tube end by pushing the jacket up against the squeeze jacket. Thus ensuring that there is no contact point between the compression sleeve and the retaining element. In this way uneven radial deformations are avoided, whereby the tendency of the jacket to migrate over the press jacket during operation of the pipe connection according to the invention is minimized. Furthermore, this also results in no contact between the jacket and the holding element in the finished connection, i.e. the jacket does not rest on the holding element.

It is also advantageous to push the jacket axially onto the tube end by using a pressing tool with at least two pressing yokes, wherein during the pushing-up one pressing yoke rests against the holding element. Thus, a reliable abutment against the compression yoke is ensured, so that the compression flange on the connecting element can be omitted. The jacket is pushed axially onto the tube end by pushing the jacket onto the compression jacket. This reduces the cycle time in the production of the connecting element, which effectively reduces the production costs of the connecting element. Furthermore, a material which is different from and possibly cheaper than the connecting element, for example, has a high stiffness but does not meet the high requirements for long-term heat resistance or creep properties which are imposed on the material of the connecting element in the preferred embodiment of the invention, can be used for the holding element.

It is also advantageous if in the pipe connection according to the invention the outer diameter of the holding element corresponds substantially to the outer diameter of the jacket. By this measure it is ensured that the compression yoke of the compression tool used in forming the pipe connection according to the invention can be applied not only to the holding element but also to the jacket, whereby errors in forming the pipe connection according to the invention can be prevented.

The pipe connection according to the invention is used in particular in lines and connection systems in potable water installations, in sprinkler installations, in heating element attachment devices, in concrete core return devices and in surface heating and/or surface cooling systems.

The tube connection and its individual components according to the invention can also be manufactured in a line-by-line manner or in a layer-by-layer manner by a manufacturing method employing a line-construction or a layer-construction, for example 3D printing. But preferably the tube is manufactured by extrusion. It is also preferred that the connecting element, the outer jacket and/or the compression jacket are manufactured by means of injection molding.

Drawings

The present invention will be described in detail below with reference to embodiments shown in the drawings. Here, it is shown that:

FIG. 1 illustrates a partial cross-sectional view of a connection element system according to an embodiment of the present invention;

fig. 2 shows a partial cross-sectional view of the embodiment according to fig. 1 of the connecting element system according to the invention with an inserted pipe end;

fig. 3 shows a partial cross-sectional view of an embodiment of a pipe connection according to the invention comprising the connection element system according to the invention shown in fig. 1 and 2; and

fig. 4 shows an enlarged detail of fig. 3.

Detailed Description

In fig. 1, an embodiment of a connecting element system 1 according to the invention is shown in a partial cross-sectional view. In the embodiment shown in fig. 1, the connecting element system 1 according to the invention comprises a connecting element 2, a compression sleeve 3 and a holding element 4. The holding element 4 is mutually engaged with the connecting element 2 and the pressing sleeve 3. The compression sleeve 3 is thereby preassembled on the connecting element 2 via the retaining element 4.

The connecting element 2 comprises a support body 6 provided with circumferential outer ribs 5, 5a, 5b, 5c for introduction into a pipe end 7 (fig. 2). The support body 6 has a raised portion 9 on the side opposite the open end 8 of the support body 6, in which a joint 10 is provided. The elevation 9 forms here a termination of the support body 6 of the connecting element 2. In the embodiment shown in fig. 1, the elevation 9 is not sufficiently high in construction to act as a pressing flange for the pressing yoke 19, 19a of the abutment tool when the pipe connection 11 (fig. 2) according to the invention is established. In this embodiment the elevation is not a circumferential compression flange. In an alternative embodiment of the invention, however, the elevation 9 can be constructed with a suitable height and with a suitable material strength, whereby a pressing tool can be applied to the elevation when establishing the pipe connection according to the invention.

In the embodiment of the invention shown in fig. 1, the circumferential outer ribs 5, 5a, 5b, 5c are configured in a zigzag manner. The angle by which the circumferential outer rib 5 closest to the open end 8 of the support body 6 is inclined with respect to the central axis 18 of the support body 6 is smaller than the angle by which the circumferential outer rib 5a adjacent to this outer rib 5 is inclined with respect to the central axis 18. The inclination angle increases continuously from the outer rib 5 to the surrounding outer rib 5c from the open end 8 of the support body 6. The eccentricity of the tube end 7, which occurs, for example, by cutting off the tube, is thereby reduced by the circumferential outer ribs 5, 5a, 5b, 5c having different inclination angles, when being pushed onto the support body 6 of the connecting element 2, which results in a simple insertion of the support body 6 into the tube end 7.

In the embodiment shown in fig. 1, the connecting element 2 is a component made of brass, in particular dezincification-resistant brass. Other metallic materials, such as, for example, may also be used in alternative embodiments of the connecting element 2Tin-zinc cast bronzes (particularly preferably the tin-zinc cast bronzes described in WO 2017/167441 A2) and stainless steel; or plastic materials such as, for example, polypropylene, glass-fibre-reinforced polypropylene, polyamide, glass-fibre-reinforced polyamide, polyvinylidene fluoride (PVDF), polyethersulfone (PES), polyphenylsulfone (PPSU), polysulphone (PSU), polyphenylene sulphide (PPS), acrylonitrile butadiene styrene copolymers (ABS) and polyester carbonates (PESC) and copolymers and blends of these polymers, it also being possible for these polymer materials to be fibre-reinforced, in particular glass-fibre-reinforced. In the case of a metal material, casting methods such as sand casting and hard die casting, forging methods such as hot forging, and turning methods can be used.

The squeeze jacket 3 has a substantially hollow cylindrical shape. A receptacle 12 is formed on the outer surface of the compression sleeve (surface facing away from the support body 6 of the connecting element 2). In the embodiment shown in fig. 1, the receptacle 12 is located at the end of the compression sleeve 3 facing away from the open end 8 of the connecting element 2. In an alternative embodiment, the receptacle 12 is also arranged so as to be movable in the axial direction in the direction of the middle of the compression sleeve 3. The compression sleeve 3 has an insertion aid 13 configured as an inclined portion. The extrusion coating 3 in the illustrated embodiment is generally formed as an injection component of PVDF. The compression sleeve 3 may have longitudinal grooves in the axial direction, which facilitate deformability of the compression sleeve 3 in the radial direction.

The connection between the connecting element 2 and the compression sleeve 3 is achieved via a holding element 4 which is constructed as a separate component. In the embodiment shown in fig. 1, the ring-shaped component is made of Polyoxymethylene (POM) by injection. The holding element 4 has on its side facing the connecting element 2 a connecting element-side engagement element 14 which in the embodiment shown in fig. 1 is directed radially inwards in the direction of the connecting element 2. The coupling element 14 on the coupling element side is configured as an engagement projection in this embodiment. In the embodiment of the invention shown in fig. 1, the connecting-element-side joining element 14 is configured circumferentially. Alternatively, it is also conceivable to provide a plurality of connecting-element-side joining elements 14 which are distributed, in particular uniformly distributed, around the inner circumference of the connecting element 2. In a particularly preferred embodiment, the connecting-element-side engagement element 14 can also have a certain degree of elasticity. The connection-side engagement element 14 is thereby resiliently engaged on the connection element 2, which gives the connection 11 according to the invention a certain flexibility.

The coupling element-side engagement element 14 engages into the engagement groove 10 of the support body 6 of the coupling element 2. The material thickness of the connecting element 14 on the connecting element side is slightly smaller than the distance between the groove connecting bridges of the connecting groove 9. The connecting-element-side engagement element 14 of the holding element 4 is thus engageable in the engagement groove 10 of the connecting element 2 and is guided in a movable manner in the radial direction. A small penetration depth of the joining element 14 on the circular-shaped joining element side in the joining groove 10 is sufficient on the basis of the connection between the joining element 2 and the holding element 4, thereby ensuring a simple assembly. The compression sleeve 3 can furthermore be moved perpendicular to the central axis 18 of the connecting element 2. This simplifies the insertability of the tube end 7 (fig. 2) since possible eccentricities of the tube can be compensated for. In addition, the movability of the coupling element-side coupling element 14 in the coupling groove 10 ensures that the tubular connection 11 according to the invention in the compressed state and the connection of the holding element 4 to be described later to the compression sleeve 3 ensure uniform radial deformation of the compression sleeve 3 over the entire longitudinal axis. This, in addition to a better seal over the entire support body length, also brings the squeeze jacket 3 and the outer jacket 15 in equilibrium, thereby preventing axial relative movement of the outer jacket 15 (fig. 2).

The holding element 4 has a press-jacket-side engagement element 16 in the direction of the press jacket 3. In the embodiment shown in fig. 1, the compression sleeve-side engagement element 16 is configured as a circumferential engagement element. In an alternative embodiment, the compression sleeve-side engagement element 16 can also be formed in multiple pieces, wherein the individual elements are arranged circumferentially, in particular uniformly, around the circumference of the holding element 4. The press-sleeve-side engagement element 16 engages with the receptacle 12 of the press sleeve 3. In the embodiment of the invention shown in fig. 1, the press-sleeve-side engagement element 16 is designed as a circumferentially locking element, which locks with the receptacle 12 of the press sleeve 3. The jacket-side engagement element 16 is in direct contact with the jacket 3.

In this way, the connecting element 2 and the pressing sleeve 3 are assembled via the holding element 4 and can be supplied as a common component to the installation site.

Between the support body 6 and the press sleeve 3, a cavity 17 is formed, which serves to accommodate the pipe end 7 of the plastic pipe or metal-plastic composite pipe. The cavity 17 is delimited in the axial direction by the holding element 4. Fig. 2 shows in partial cross-section an embodiment of a tube connection 11 according to the invention with the connecting element system 1 according to the invention shown in fig. 1 before the outer jacket 15 is mounted on the compression sleeve 3, in fig. 2 the tube end 7 of the all-plastic tube being introduced into the cavity 17 between the support body 6 and the compression sleeve 3. The connecting-element-side engagement element 14 can move unimpeded in the engagement groove 10 even during the pressing operation.

The outer sleeve, which in the embodiment shown is configured as a sliding sleeve, serves to fasten the pipe end 7 to the support body 6. According to the embodiment shown in fig. 2, the outer sleeve 15 is a sleeve made of polyvinylidene fluoride (PVDF) having a constant cross section over substantially its entire length and having lead-in bevels 20, 20a at only two ends, respectively. Alternatively, the jacket 15 can also be composed of other materials, in particular advantageously of crosslinked polyethylene (in particular PE-Xa, PE-Xb or PE-Xc). The outer jacket 15 in this embodiment has an inner surface with an average roughness value Ra in the range of 4 μm. The outer sleeve 15 with a higher roughness of the inner surface shows a smaller tendency of the outer sleeve 15 to move relatively over the pipe end 7, in particular under temperature-varying stresses.

To produce the pipe connection 11 according to the invention, the jacket 14 is first pushed onto the pipe end 7 of the plastic pipe. For this purpose, a pressing or pushing tool having two pressing yokes 19, 19a that can be moved axially relative to one another is used. For the pushing-on process, one pressing yoke 19 is attached to the side of the holding element 4 facing away from the tube end 7, while the other pressing yoke 19a is attached to the side of the outer sleeve 15 facing away from the tube end 7. The compression yokes 19, 19a are then moved towards each other, whereby the outer sleeve 15, which is configured as a sliding sleeve, is slid in the axial direction up against the compression sleeve 3 to secure the pipe end 7 on the support body 6.

The compression sleeve 3 is compressed by pushing the outer sleeve 15 and the material of the tube end 7 is pressed onto the support body 6 of the connecting element 2. The serrated circumferential outer ribs 5, 5a, 5b, 5c of the support body 6 are thereby machined into the material of the pipe end 7, as a result of which the tightness of the pipe connection 11 according to the invention is achieved.

By compressing the press sleeve 3 when the outer sleeve 15 is pushed up, the contact between the press sleeve-side engagement element 16 and the receptacle 12 of the press sleeve 3 is released, as can be seen from the enlarged detail view according to fig. 4. Likewise, the holding element 4 does not touch the outer sleeve 15. It is helpful for this to be the case that the side of the holding element 4 facing the jacket 15 is substantially parallel to the lead-in chamfer 20 of the jacket 15. For this purpose, it is also possible to use lower quality materials for the press jacket 3.

The resulting pipe connection 11 according to the invention is shown in fig. 3 in a partial cross-sectional view. In the embodiment shown in fig. 3, the pipe end 7 has a substantially constant cross section. In alternative embodiments, the expanded pipe end 7 can also be used in the pipe connection 11 according to the invention. For this purpose, after the sleeve 15 has been pushed onto the pipe end 7, an expansion tool is introduced into the pipe end 7 and the pipe end 7 is expanded by means of the expansion tool. A corresponding process is then carried out to produce the pipe connection 11 according to the invention without the expanded pipe end 7. However, such a tube connection 11 according to the invention is preferred according to the invention without an expanded tube end 7 according to the invention. In this embodiment, the expanded pipe end 7 is introduced into the cavity 17 between the support body 6 and the compression sleeve 3.

The further pipe ends 7 can be coupled to the optionally present further support body 6 of the connecting element 2 in the manner described in order to produce a further pipe connection 11 according to the invention. The further tube end can have the same tube structure as the tube of the tube end 7 of the support body 6, but can also have a different structure than the tube of the tube end 7 of the support body 6.

In an alternative embodiment of the invention, the outer jacket 15 can also be configured as a radial extrusion jacket.

According to the illustrated embodiment of the invention, the tube of the tube end 7 is an all-plastic tube composed of cross-linked polyethylene (PE-X, in particular PE-Xa, PE-Xb or PE-Xc). Instead of this, all plastic tubes made of other materials, as well as plastic composite tubes and metal plastic composite tubes, may also be used in other embodiments of the invention. Preferably, however, the layer facing the net diameter of the tube in the case of plastic composite tubes and metal plastic composite tubes is a layer composed of crosslinked polyethylene (PE-X), in particular PE-Xa, PE-Xb or PE-Xc.

The connecting element 2 may be a threaded molding or an unthreaded molding, i.e. an unthreaded connecting element. This includes, in particular, couplings without threads, coupling angles, multiple distributors, tees, wall angles, system transitions, angled transitions, respectively. The term "thread molding" thus relates to a connecting element having at least one thread molding. This includes, in particular, couplings, coupling angles, multiple distributors, tees, wall angles, system transitions, transitions and angled transitions, each having at least one internal thread and/or external thread.

The present invention is described in detail with reference to the embodiments thereof shown in the drawings. It is to be understood that the invention is not limited to the illustrated embodiments, but is to be obtained from any of the claims.

Claims (15)

1. A connection element system (1) for establishing a pipe connection (11) between a connection element (2) and a plastic pipe, a plastic composite pipe or a metal plastic composite pipe, the connection element system (1) comprising:

a connecting element (2) to be fitted with a squeeze jacket (3), said connecting element (2) comprising at least one support body (6) provided with a plurality of circumferential outer ribs (5, 5a, 5b, 5 c) for pushing up a tube end (7), and

an extrusion sleeve (3),

it is characterized in that the method comprises the steps of,

the connecting element system (1) further comprises a holding element (4), the holding element (4) being interengaged with the connecting element (2) and the compression sleeve (3).

2. The connecting element system (1) according to claim 1, characterized in that the connecting element (2) has an engagement groove (10) and the holding element (4) has at least one connecting element-side engagement element (14), the connecting element-side engagement element (14) engaging into the engagement groove (10) of the connecting element (2).

3. The connecting element system (1) according to claim 2, characterized in that the engagement groove (10) is configured in a raised portion (9) on the connecting element (2), the raised portion (9) forming an axial termination of the support body (6).

4. A connecting element system (1) according to any one of claims 1 to 3, characterized in that the holding element (6) has a press-sleeve-side engagement element (16), the press-sleeve-side engagement element (16) being interengaged with a cooperating receptacle (12) of the press sleeve (3).

5. The connecting element system (1) according to any one of claims 1 to 4, characterized in that the compression sleeve (3) is composed of an elastically deformable polymer material.

6. The connecting element system (1) according to any one of claims 1 to 5, characterized in that the connecting element system (1) further comprises an outer sleeve (15) for fastening the compression sleeve (3) on a support body (6) of the connecting element (2).

7. A pipe connection (11) between a pipe end (7) of a plastic, plastic or metal-plastic composite pipe and a connecting element (2), the pipe connection comprising:

a pipe end (7) of a plastic pipe, a plastic composite pipe or a metal plastic composite pipe;

the connecting element system (1) according to any one of claims 1 to 6, wherein a support body (6) of the connecting element (2) is introduced into the tube end (7);

an extrusion sleeve (3); and

-a jacket (15), said jacket (15) being mounted to said extrusion jacket (3) to secure said pipe end (7) on a support body (6) of said connection element (2).

8. Pipe connection (11) according to claim 7, characterized in that the holding element (4) is not in radial contact with the press jacket (3) and/or the outer jacket (14).

9. Pipe connection (11) according to claim 7 or claim 8, characterized in that the side of the pressing sleeve-side engagement element (16) facing away from the support body (6) extends at least partially essentially parallel to the lead-in bevel (20) of the jacket (15).

10. A pipe connection (11) according to any of claims 7-9, characterized in that the coupling element-side engagement element (14) is configured as a plurality of individual elements arranged along the inner circumference of the holding element (4).

11. A pipe connection (11) according to any of claims 7-10, characterized in that the outer jacket (15) is configured as a sliding sleeve for axially sliding up the press jacket (3).

12. A method for establishing a pipe connection (11) according to any of claims 7 to 11, wherein the method comprises the steps of:

pushing the outer sleeve (15) on a plastic pipe, a plastic composite pipe or a metal plastic composite pipe;

-introducing a support body (6) of the connecting element (2) into the tube end (7);

and

the jacket (15) is pushed axially onto the press sleeve (3), whereby the pipe end (7) is pressed onto the support body (6) of the connecting element (2).

13. A method according to claim 11, characterized in that the press sleeve (3) is pressed onto the pipe end (7) when the jacket (15) is pushed axially onto the pipe end (7), whereby the press sleeve-side engagement element (16) is free from contact points with the press sleeve (3).

14. Method according to claim 12 or 13, characterized in that the jacket (15) is pushed axially onto the tube end (7) by using a pressing tool with at least two pressing yokes (19, 19 a), wherein one pressing yoke (19) is pressed against the holding element (6) during the pushing.

15. Method according to any one of claims 12 to 14, characterized in that in the tube connection (11) the outer diameter of the holding element (4) essentially corresponds to the outer diameter of the jacket (15).