CN116615620A - Connection element system for producing a pipe connection, pipe connection comprising the same and method for producing 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 pipe connections, pipe comprising the connection element system Connections and methods of establishing such pipe connections

technical field

The invention relates to a connecting element system for establishing a pipe connection between a connecting element and a plastic pipe, a plastic composite pipe or a metal-plastic composite pipe, the connecting element system comprising a connecting element fitted with an extrusion sleeve, and an extrusion sleeve, the The connecting element comprises at least one support body provided with a plurality of surrounding outer ribs for pushing on the pipe end. The invention also relates to a pipe connection comprising such a connecting element system, and to a method for producing such a pipe connection.

Background technique

A connecting element for a double-socket connection and a pipe connection comprising this connecting element are known from the prior art, for example from DE 10 2016 117 480 A1. Therein a pipe connection is disclosed which comprises a support body, an inner sleeve or extrusion sleeve and an outer sleeve which is pushed on axially. In order to bring the pressing yoke of the pressing tool, which is required for pushing on the sleeve, against the pressing sleeve, the pressing sleeve has a pressing flange formed in one piece with the pressing sleeve. This causes the extrusion sleeve to have uneven radial deformation after being pushed on the outer sleeve. This in turn results in a greater displacement of the sleeve during installation of such a pipe connection in the pipeline system, which requires an additional fastening of the sleeve to the support body. Furthermore, the non-uniform radial deformation of the sleeve impairs the tightness of such pipe connections. Furthermore, the extrusion sleeve is rigidly fastened to the support body. The rigid connection makes it difficult for the tube end to be pushed into the receiving space between the support body and the inner sleeve. This is the case in particular when the tube ends are of extremely oval configuration, which can be the case in particular after cutting off the tube connections, or when there is a considerable eccentricity of the tubes.

Contents of the invention

Against this background, the object of the present invention is to provide a connecting element system for establishing pipe connections which overcomes the disadvantages of the prior art. In particular, the connecting element system according to the invention leads to a long-term tight pipe connection in the pipe connection formed therefrom. In addition, especially in the case of extreme ellipse or eccentricity, it should be easy to push the tube end between the support body and the extrusion sleeve or the inner sleeve.

According to the invention, this and other objects are achieved by a connecting element system for establishing a pipe connection having the features of claim 1 , by a pipe connection having the features of claim 6 and by a system for establishing pipe connections having the features of claim 10 The connected method is implemented. Preferred embodiments of the connection element system according to the invention, the pipe connection according to the invention and the method according to the invention are each described in the dependent claims.

In contrast to the rigid locking methods of the prior art, the invention proposes a flexible connection between the compression sleeve and the connection element by means of a retaining element as a separate component, which engages the connection element and the compression sleeve. The press sleeve is thus preassembled on the connecting element, which simplifies the production of the pipe connection. Since the extrusion sleeve is designed as a separate component which is not at any point in contact with the medium flowing through the tube connection according to the invention during use of the tube connection according to the invention, it is possible to use more cost-effective and/or Or less chemically resistant material as extrusion sleeve material. By having the retaining element as a separate component, the compression sleeve has a certain movability relative to the central axis of the connecting element. This simplifies the insertability of the tube, since possible eccentricities of the tube can be compensated. Furthermore, besides providing a better tightness over the entire length of the support body, the movability of the extrusion sleeve with respect to the central axis also brings the extrusion sleeve and the casing into equilibrium, thereby preventing axial relative movement of the casing .

Therefore, the present invention consists in providing a connecting element system for establishing a pipe connection between a connecting element and a plastic pipe, a plastic composite pipe or a metal-plastic composite pipe, the connecting element system comprising a connecting element fitted with an extrusion sleeve, and an extrusion The connecting element comprises at least one support body provided with a plurality of surrounding outer ribs for pushing on the end of the pipe, wherein the connecting element system according to the invention is characterized in that the connecting element system also comprises a retaining element, the retaining element and The connection element and the extrusion sleeve engage each other. 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: a pipe end of a plastic pipe, a plastic composite pipe or a metal-plastic composite pipe; according to The connection element system of the invention, wherein the support body of the connection element is introduced into the pipe end; an extrusion sleeve and an outer sleeve, the sleeve is mounted on the extrusion sleeve to fasten the pipe end on the support body of the connection element. Finally, the invention also relates to a method for producing a pipe connection according to the invention, wherein the method comprises the steps of: pushing the outer sleeve onto a plastic pipe, a plastic composite pipe or a metal-plastic composite pipe; introducing the support body of the connecting element into the pipe end and pushing the sleeve axially over the end of the tube of the support in which the connecting element is inserted.

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

With regard to the connecting element system according to the invention, it can be advantageous if the connecting element has an engaging groove and the holding element has at least one connecting element-side engaging element which engages in the engaging groove of the connecting element. Even during the pressing process, the engaging element on the connecting element side of the retaining element can move unhindered into the engaging groove. Due to the circular shape of the connecting element and the retaining element, even a small penetration depth of the engaging element on the connecting element side in the engaging groove is sufficient, thereby ensuring simple assembly. It can also be advantageous here if the engagement groove is formed in a rise on the connecting element, which rise forms the axial end of the support body. Thus, the engagement groove can be integrated into the connecting element in a simple manner.

It has also proven to be advantageous if the retaining element has an engagement element on the press sleeve side, which engages with a cooperating receptacle of the press sleeve. Thus, in the preassembled state of the connecting element system according to the invention, the compression sleeve is connected to the connecting element via the retaining element in a relatively movable manner. This contributes decisively to the easy insertion of the tube end even when the tube end is heavily eccentric, thereby simplifying the installation of the tube connection.

It is also advantageous if the joining element on the connecting element side is formed as a plurality of individual elements arranged along the inner circumference of the holding element. The individual elements are preferably designed as individual spring elements. As a result, the coupling element on the connecting element side engages elastically on the connecting element, which imparts a certain flexibility to the connection. This also enables simpler assembly of the connecting element system according to the invention. Furthermore, the design with the spring element enables a defined movability of the retaining element as well as of the inner sleeve. Finally, the spring element also enables better compensation of possible manufacturing fluctuations by the connecting element system according to the invention.

It is also advantageous if the engagement groove of the connecting element has a groove slope. Such a groove bevel prevents the retaining element from being pushed too far onto the connecting element during assembly. Furthermore, the slope of the groove prevents the retaining element from being pushed away from the support body even during operation, since a change in length of the inner sleeve can occur during radial compression of the inner sleeve or due to thermal expansion, for example, during operation. will affect the holding element.

It is also advantageous if the squeeze sleeve consists of an elastically deformable polymer material. This further increases the stability of the pipe connection according to the invention.

In a preferred embodiment of the invention, the connection element system according to the invention also comprises a sleeve for fastening the compression sleeve to the support body of the connection element. Via the sleeve, the compression sleeve is fastened to the support body and the tube end is pressed into the surrounding outer rib of the support body. This ensures the tightness of the pipe connection according to the invention. Furthermore, the compression sleeve is pressed in the direction of the support body, so that the compression sleeve loses contact with the retaining element and no longer touches the retaining element in the finished constructed pipe connection according to the invention.

It is understood that, when several supports are present on the connecting element, a compression sleeve can be assigned to each support of the connecting element, which is indirectly connected to the connecting element via the holding element. In a preferred embodiment of the invention, according to the invention, each support body of the connection element is connected to the compression sleeve via a retaining element.

With regard to the pipe connection according to the invention, it is advantageous if the retaining element does not come into contact with the extrusion sleeve and/or the outer sleeve. Any suitable material can thus be used for the retaining element, in particular a material that is accompanied by a chemical reaction during contact with the extrusion sleeve and/or with the outer sleeve during use of the tube connection according to the invention.

In a preferred embodiment of the pipe connection according to the invention, the non-contact between the outer sleeve and the retaining element is advantageous if the side of the engagement element on the press sleeve side facing away from the support body is at least partially substantially parallel to the outer sleeve The lead-in slope extends.

It is also preferred that the sleeve is configured as a sliding sleeve for sliding axially on the extrusion sleeve. The resulting slip-on connection is highly leak-tight and has a high degree of connection reliability. Sliding the sliding sleeve onto the extrusion sleeve causes an expansion of the sliding sleeve, whereby the sliding sleeve exerts a radially inwardly directed force on the extrusion sleeve. This force is transmitted to the tube, which presses the tube onto the support body provided with the surrounding outer ribs, thereby forming a permanently tight connection between the tube and the connecting element. Preferably, the squeeze sleeve comprises at least one cylindrical section. The cylindrical section brings about a reduction in the inclination of the extrusion sleeve with respect to axial relative movements (for example due to temperature-varying stresses). The at least one cylindrical section preferably extends generally over the majority of the length of the extrusion sleeve, preferably over at least 60% of the length of the extrusion sleeve, particularly preferably over at least 75% of the length of the extrusion sleeve. Alternatively or additionally, the extrusion sleeve may comprise axial slits and/or contours, by which the ring stiffness of the extrusion sleeve is reduced and the sliding sleeve is facilitated and also improved Force transmission to the pipe end. On its inner surface, the extrusion sleeve can have an inner surface structure or contour, which is suitable for preventing possible axial relative movements of the extrusion sleeve on the tube, for example due to stresses caused by temperature changes. The outer surface of the extrusion sleeve can also have a surface structure or contour that is suitable for preventing possible axial relative movements of the sleeve due to stress, for example due to temperature changes. Alternatively or additionally, the outer surface of the squeeze sleeve can have a surface structure or a surface profile which is suitable for improving the push-on properties of the sleeve (eg reduction of pressing force, reduction of noise during connection establishment). In order to achieve this surface property, the inner surface of the jacket and/or the outer surface of the extrusion jacket can have an average roughness value Ra in the range of 1 μm up to half the average wall thickness of the jacket and/or at 5 μm up to the average wall thickness of the jacket The average roughness depth Rz and/or multiple visible asperities in the range of half the thickness, the depth of the asperities should not exceed half the average wall thickness of the casing. The term "mean roughness value" or "average roughness" (shown by the symbol "Ra") of a surface as used herein means the arithmetic mean 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 (shown by the symbol "Rz") as used herein means the roughness depth according to DIN EN ISO 4287/4288. With regard to the surface properties of the inner and outer surfaces of the extrusion sleeve and the inner surface of the jacket, reference should be made to DE 10 2015 122 345 A1, to which reference is expressly made. The extrusion sleeve can also comprise, for example, at least one rib on its outer side, in particular triangular or rectangular. In addition, the outer surface of the extrusion sleeve can be provided with a coating in order to improve the slideability of the sliding sleeve (for example, reduction of pressing forces, reduction of noise during connection production).

It is also advantageous if the tube ends have a substantially equal internal diameter or a widened compared to the conventional internal diameter (ie the internal diameter that the tube has substantially over its entire tube length after extrusion). Inner diameter. It is however preferred that the tube ends have a substantially equal diameter compared to the normal inner diameter of the tube. As used therein, the term "substantially equal inner diameter compared to the conventional inner diameter" means that the inner diameter of the tube end has not been widened by a separate expansion process using a so-called expansion tool. It is very expedient here if the inner diameter of the pipe end is slightly increased by pushing in the support body of the connecting element relative to the conventional inner diameter, for example by a maximum of approximately 5%, or the pipe end is passed through in the pipe connection according to the invention. The effect of the sliding sleeve on the axial slide is compressed so that the inner diameter of the tube end is reduced slightly, for example by up to about 10%, relative to the normal inner diameter. In the case of the pipe connection according to the invention, the pipe ends having a substantially equal inner diameter compared to conventional inner diameters, the production method thereof is considerably simplified, since the step of expanding the pipe ends is omitted. If the pipe ends have an inner diameter that is widened compared to the conventional inner diameter, the pipe connection according to the invention has better sealing and connection reliability due to the memory properties of the pipe material.

Preferred materials for the connecting elements according to the invention are polymeric materials such as polypropylene and glass-fiber-reinforced polypropylene, polyamide and glass-fiber-reinforced polyamide; heat-resistant thermoplastics such as polyphenylsulfone (PPSU), polyamide Vinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PSU), polyphenylene sulfide (PPS), acrylonitrile butadiene styrene (ABS), polyoxymethylene (POM) and polyester Carbonate (PESC) and copolymers and blends of these polymers, wherein these polymer materials can also be reinforced with fibers, especially with glass fibers; and metal materials, such as brass, especially Tin-zinc cast bronze and stainless steel. Heat-resistant thermoplastics, such as especially polyphenylsulfone and polyvinylidene fluoride, are particularly preferred for producing the connecting element according to the invention. The term "heat-resistant thermoplastic" as used herein refers to the heat deformation resistance and heat stability of this group of materials and refers to thermoplastic polymer materials having a heat deformation resistance at a temperature of at least 150°C. The upper temperature limit at which such heat-resistant plastics can be used is related to the material used, where the upper limit of usability of this polymeric material is 260°C.

Use according to the invention preferably made of polyethylene (PE, especially PE 100 and PE-RT (polyethylene with higher heat resistance)), cross-linked polyethylene (PE-X, especially PE-Xa, PE-Xb and PE-Xc), polypropylene (especially random polypropylene PP-R) and polybutylene (PB); Layers of crosslinked polyethylene (PE-X, especially PE-Xa, PE-Xb and PE-Xc), polypropylene (especially random polypropylene PP-R) and/or polybutylene (PB) Plastic composite pipes and metal plastic composite pipes (MKV pipes) are used as plastic pipes. A layer of ethylene-vinyl alcohol copolymer (EVOH) may additionally be present as oxygen barrier layer. According to the invention the metal-plastic composite pipe (MKV-pipe) preferably consists of polyethylene (PE, especially PE 100 and PE-RT), crosslinked polyethylene (PE-X, especially PE-Xa, PE-Xb and PE -Xc), a layer of polypropylene (in particular atactic polypropylene PP-R) and/or polybutene (PB) and at least one layer of metal, preferably aluminum. The metal layers are preferably butt welded. In the case of plastic composite pipes and MKV pipes, layers of adhesion promoters can be introduced between the individual layers. According to the invention, all tubes of a tube connection according to the invention can be constructed identically or one or more of them can have a different tube structure. Furthermore, the pipe according to the invention can also be fiber-reinforced. The fiber reinforcement of the pipes can be present in individual or all pipes, over the entire pipe length or only in sections. 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 "cross-linked polyethylene" is a material with shape memory or the so-called "memory effect". This memory effect consists in the fact that crosslinked polyethylene tries to return to its original shape again after a change in its external geometry. When dilating the tube, this causes the tube comprising PE-X to try again after dilation to reach the inner diameter of the tube before dilation. Since the support body of the connecting element is inserted into the expanded pipe end after expansion, the memory effect leads to a particularly high sealing of the pipe connection according to the invention when using pipes comprising at least one layer of cross-linked polyethylene sex.

The connecting element can be a threaded molding or a non-threaded molding, ie a connecting element without a thread. This includes in particular couplings without thread, coupling corners, multiple distributors, T-pieces, wall T-pieces, wall corners, system transitions, transition pieces, angled transition pieces, respectively. The term "thread molding" thus relates to a connecting element having at least one thread molding. This includes in particular couplings, coupling corners, multiple distributors, T-pieces, wall T-pieces, wall corners, system transitions, transition pieces and angled transitions each with at least one internal and/or external thread pieces.

According to the invention, preferably the materials described for the connection element of the pipe connection according to the invention are suitable as materials for the retaining element, outer sleeve and/or extrusion sleeve. Heat-resistant plastics and especially polyphenylsulfone, polyvinylidene fluoride, polypropylene, polyamide (PA) and polyoxymethylene (POM) are particularly preferred as material for the jacket and/or extrusion sleeve. Crosslinked polyethylenes (especially PE-Xa, PE-Xb and PE-Xc) are also particularly preferred as material for the jacket and/or extrusion sleeve. For the holding element, materials with higher stiffness are particularly preferred, such as polyoxymethylene, especially with glass fibers; polyamide, especially with glass fibers; polypropylene with glass fibers; polyvinylidene fluoride (PVDF); Polyphenylsulfone (PPSU) and so on.

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

With regard to the method of establishing a pipe connection according to the invention, it is preferred that, when the sleeve is pushed axially onto the pipe end, the extrusion sleeve is pressed onto the pipe end so that the engagement element on the side of the extrusion sleeve is in contact with the extrusion sleeve. The sleeve has no contact points. By pushing the outer sleeve onto the extrusion sleeve, the outer sleeve is thereby pushed axially onto the tube end. It is thus ensured that there are no contact points between the compression sleeve and the holding element. In this way, uneven radial deformations are avoided, whereby the tendency of the sleeve to migrate over the extrusion sleeve during the pipe connection work according to the invention is minimized. Furthermore, this also results in no contact between the outer sleeve and the holding element in the completed connection, ie the outer sleeve does not bear against the holding element.

It is also advantageous if the sleeve is pushed axially onto the tube end by using a pressing tool with at least two pressing yokes, one pressing yoke resting against the holding element during the pushing on. A secure contact with the pressure yoke is thus ensured, so that a pressure flange on the connecting element can be dispensed with. In this case, the outer sleeve is pushed axially onto the tube end by pushing the outer sleeve onto the extrusion sleeve. As a result, cycle times can be reduced during the production of the connecting element, which effectively reduces the production costs of the connecting element. In addition, a different and possibly cheaper material can be used for the holding element than the connecting element, which material, for example, has high stiffness but does not meet the high requirements for long-term heat resistance or creep behavior, wherein in a preferred embodiment of the invention These requirements are imposed on the material of the connecting elements in the manner.

It is also advantageous if, in the pipe connection according to the invention, the outer diameter of the retaining element substantially corresponds to the outer diameter of the sleeve. This measure ensures that the compression yoke of the compression tool used when forming the pipe connection according to the invention can be applied not only to the holding element, but also to the jacket, thereby preventing error.

The pipe connection according to the invention finds particular application in piping and connection systems in potable water installations, in sprinkler installations, in heating element attachments, in concrete core return installations and in surface heating and/or surface cooling systems.

The pipe connection according to the invention and its individual components can also be produced row-by-row or layer-by-layer by manufacturing methods using row or layer construction, such as 3D printing. Preferably, however, the tube is produced by extrusion. It is also preferred to produce the connecting element, the sleeve and/or the extrusion sleeve by means of injection moulding.

Description of drawings

The present invention shall be described in detail below with reference to the embodiments shown in the accompanying drawings. Shown here:

Figure 1 shows a partial cross-sectional view of a connecting element system according to an embodiment of the 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 inserted pipe ends;

Figure 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 Figures 1 and 2; and

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

Detailed ways

In FIG. 1 , an embodiment of a connecting element system 1 according to the invention is shown in partial cross-section. 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 retaining element 4 . The retaining element 4 engages with the connecting element 2 and the compression sleeve 3 . The compression sleeve 3 is thus preassembled on the connecting element 2 via the retaining element 4 .

The connecting element 2 comprises a support body 6 provided with a surrounding outer rib 5, 5a, 5b, 5c for introduction into a pipe end 7 (Fig. 2). The support body 6 has, on the side opposite the open end 8 of the support body 6 , a rise 9 in which a joint seam 10 is provided. The elevation 9 here forms the termination of the support body 6 of the connecting element 2 . In the embodiment shown in FIG. 1 , the elevation 9 is not configured high enough to act as a pressing against the pressing yokes 19 , 19 a of the tool when producing the pipe connection 11 according to the invention ( FIG. 2 ). flange. In this embodiment the elevation is not a surrounding pressure flange. In an alternative embodiment of the invention, however, the elevation 9 can be constructed with a suitable height and a suitable material strength, so that a pressing tool can be applied to the elevation when producing the pipe connection according to the invention.

In the embodiment of the invention shown in FIG. 1 , the surrounding outer ribs 5 , 5 a , 5 b , 5 c are designed in a zigzag shape. The surrounding outer rib 5 closest to the open end 8 of the support body 6 is inclined relative to the central axis 18 of the support body 6 at a smaller angle than the circumferential outer rib 5a adjacent to this outer rib 5 relative to the central axis 18. Angle. The angle of inclination increases continuously starting from the open end 8 of the support body 6 from the outer rib 5 to the surrounding outer rib 5 c. As a result, the eccentricity of the tube end 7 , which occurs, for example, through a cut-off tube, is reduced by the surrounding outer ribs 5 , 5 a , 5 b , 5 c with different inclination angles when pushed onto the support body 6 of the connecting element 2 , which enables the support The body 6 is simply inserted into the tube end 7 .

In the embodiment shown in FIG. 1 , connecting element 2 is a component made of brass, in particular dezincification-resistant brass. In alternative embodiments of the connection element 2 other metallic materials can also be used, such as Tin-zinc cast bronzes (especially preferably tin-zinc cast bronzes as described in WO 2017/167441 A2) and stainless steel; or plastic materials such as for example polypropylene, glass fiber reinforced polypropylene, polyamide, glass fiber reinforced polyamide, Polyvinylidene fluoride (PVDF), polyethersulfone (PES), polyphenylsulfone (PPSU), polysulfone (PSU), polyphenylene sulfide (PPS), acrylonitrile butadiene styrene copolymer (ABS) and Polyester carbonate (PESC) and copolymers and blends of these polymers, where these polymer materials can also be reinforced with fibres, especially with glass fibres. In the case of metallic materials, casting methods such as sand casting and die casting, forging methods such as hot forging, and turning methods can be used.

The extrusion sleeve 3 has essentially the shape of a hollow cylinder. A receptacle 12 is formed on the outer surface of the extrusion sleeve (the surface of the support body 6 facing away from the connection element 2 ). In the embodiment shown in FIG. 1 , the receptacle 12 is located at the end of the extrusion sleeve 3 facing away from the open end 8 of the connecting element 2 . In an alternative embodiment, the receptacle 12 is also arranged displaceably in the axial direction in the direction of the center of the extrusion sleeve 3 . The compression sleeve 3 has an insertion aid 13 configured as a bevel. In the embodiment shown, the extrusion sleeve 3 is designed overall as an injection part made of PVDF. The extrusion sleeve 3 can have longitudinal grooves in the axial direction which contribute to the deformability of the extrusion sleeve 3 in the radial direction.

The connection between the connection element 2 and the compression sleeve 3 takes place via the retaining element 4 which is designed as a separate component. In the embodiment shown in FIG. 1 it is an annular component made of polyoxymethylene (POM) produced by injection molding. On its side facing the connecting element 2 , the holding element 4 has a connecting element-side engagement element 14 which in the embodiment shown in FIG. 1 points radially inwards in the direction of the connecting element 2 . . In this embodiment, the engaging elements 14 on the connecting element side are designed as engaging projections. In the embodiment of the invention shown in FIG. 1 , the joining element 14 on the connecting element side is designed circumferentially. As an alternative thereto, it is also conceivable to involve a plurality of connecting element-side joining elements 14 which are arranged distributed, in particular evenly distributed, around the inner circumference of the connecting element 2 . In a particularly preferred embodiment, the joining element 14 on the connecting element side can also have a certain degree of elasticity. As a result, the connection-side engagement element 14 engages elastically on the connection element 2 , which confers a certain flexibility on the connection 11 according to the invention.

The connecting element-side engaging element 14 engages in the engaging groove 10 of the support body 6 of the connecting element 2 . The material thickness of the joining element 14 on the connecting element side is slightly smaller than the distance between the groove bridges of the joining groove 9 . The connecting element-side engaging element 14 of the holding element 4 can thus engage in the engaging groove 10 of the connecting element 2 and be guided there so as to move in the radial direction. Due to the circular shape of the connection between the connecting element 2 and the holding element 4 , a small penetration depth of the engaging element 14 on the connecting element side into the engaging groove 10 is sufficient, thereby ensuring simple assembly. Furthermore, the compression sleeve 3 can 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. In addition, the movability of the coupling element 14 on the connecting element side in the coupling groove 10 ensures that the pipe connection 11 according to the invention is in the compressed state and that the compression is ensured by the connection of the retaining element 4 to the compression sleeve 3 to be described later. Uniform radial deformation of the pressure sleeve 3 over the entire longitudinal axis. In addition to a better seal over the entire length of the support body, this brings the extrusion sleeve 3 and the outer sleeve 15 into equilibrium, thereby preventing axial relative movements of the outer sleeve 15 ( FIG. 2 ).

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

In this way, the connecting element 2 and the compression sleeve 3 are assembled via the retaining element 4 and can be provided as a common component at the installation site.

A cavity 17 is formed between the support body 6 and the extrusion sleeve 3 for receiving the tube end 7 of a plastic tube or a metal-plastic composite tube. The cavity 17 is delimited in the axial direction by the holding element 4 . FIG. 2 shows an embodiment of a pipe connection 11 according to the invention with the connection element system 1 according to the invention shown in FIG. In FIG. 2 the tube end 7 of the all-plastic tube is introduced into the cavity 17 between the support body 6 and the extrusion sleeve 3 . The coupling element 14 on the connecting element side can move unhindered in the coupling groove 10 even during the pressing process.

In the illustrated embodiment, a sleeve designed as a slip-on sleeve is used to fasten the pipe end 7 to the support body 6 . According to the embodiment shown in FIG. 2 , the jacket 15 is a sleeve made of polyvinylidene fluoride (PVDF), which has a constant cross-section substantially over its entire length and only at two ends. Each has an introduction bevel 20, 20a. Alternatively, the jacket 15 can also consist of another material, particularly advantageously of cross-linked polyethylene (in particular PE-Xa, PE-Xb or PE-Xc). In this embodiment the jacket 15 has an inner surface with an average roughness value Ra in the range of 4 μm. A jacket 15 with a higher roughness of the inner surface exhibits a tendency for a smaller jacket 15 to move relative to the pipe end 7, especially under temperature changing stresses.

To produce the pipe connection 11 according to the invention, the sleeve 14 is first pushed onto the pipe end 7 of the plastic pipe. For this purpose, a pressing tool or pushing tool is used which has two pressing yokes 19 , 19 a which are axially movable relative to one another. For the push-on process, one pressure yoke 19 is brought into contact with the side of the holding element 4 facing away from the tube end 7 , while the other pressure yoke 19 a is pressed against the side of the jacket 15 facing away from the tube end 7 superior. The compression yokes 19 , 19 a are then moved towards each other, whereby the sleeve 15 , which is designed as a sliding sleeve, is slid onto the compression sleeve 3 in the axial direction in order to fasten the tube end 7 to the support body 6 .

Pushing on the sleeve 15 compresses the extrusion sleeve 3 and presses the material of the pipe end 7 onto the support body 6 of the connecting element 2 . As a result, the serrated circumferential outer ribs 5 , 5 a , 5 b , 5 c of the support body 6 are worked into the material of the pipe end 7 , thereby achieving a tightness of the pipe connection 11 according to the invention.

By compressing the compression sleeve 3 when the sleeve 15 is pushed on, the contact between the coupling element 16 on the compression sleeve side and the receptacle 12 of the compression sleeve 3 is released, as can be seen in the enlarged detail view according to FIG. 4 . Likewise, the retaining element 4 does not touch the jacket 15 either. It is helpful for this if the side of the retaining element 4 facing the sleeve 15 is substantially parallel to the introduction bevel 20 of the sleeve 15 . It is also possible to use a lower quality material for the extrusion sleeve 3 for this purpose.

The pipe connection 11 obtained according to the invention is shown in partial cross section in FIG. 3 . In the embodiment shown in FIG. 3 the tube end 7 has a substantially constant cross section. In an alternative embodiment, an expanded tube end 7 can also be used in the tube connection 11 according to the invention. For this purpose, after the sleeve 15 has been pushed onto the tube end 7 , an expansion tool is introduced into the tube end 7 and the tube end 7 is expanded by means of the expansion tool. The corresponding process for producing the tube connection 11 without the expanded tube end 7 according to the invention then follows. However, such a tube connection 11 according to the invention without an expanded tube end 7 is preferred. In this embodiment, the expanded tube end 7 is introduced into the cavity 17 between the support body 6 and the extrusion sleeve 3 .

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

In an alternative embodiment of the invention, the sleeve 15 can also be designed as a radial extrusion sleeve.

According to the illustrated embodiment of the invention, the tube of the tube end 7 is an all-plastic tube consisting of cross-linked polyethylene (PE-X, especially PE-Xa, PE-Xb or PE-Xc). As an alternative thereto, in other embodiments of the invention, all-plastic pipes made of other materials and plastic- and metal-plastic composite pipes can also be used. Preferably, however, in the case of plastic composite pipes and metal-plastic composite pipes, the layer facing the net diameter of the pipe consists of cross-linked polyethylene (PE-X), especially PE-Xa, PE-Xb or PE-Xc layer.

The connecting element 2 can be a threaded molding or a non-threaded molding, ie a connecting element without a thread. This includes in particular couplings without thread, coupling corners, multiple distributors, T-pieces, wall T-pieces, wall corners, system transitions, transition pieces, angled transition pieces, respectively. The term "thread molding" thus relates to a connecting element having at least one thread molding. This includes in particular couplings, coupling corners, multiple distributors, T-pieces, wall T-pieces, wall corners, system transitions, transition pieces and angled transitions each with at least one internal and/or external thread pieces.

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

Claims (15)

1. A connecting element system (1) for establishing a pipe connection (11) between a connecting element (2) and a plastic pipe, a plastic composite pipe or a metal-plastic composite pipe, said connecting element system (1) comprising: A connecting element (2) fitted with a squeeze sleeve (3), said connecting element (2) comprising a plurality of surrounding outer ribs (5, 5a, 5b, 5c) for pushing on the pipe end (7) At least one support (6) of , and Squeeze sleeve (3), It is characterized in that, The connecting element system (1) also comprises a retaining element (4) which interengages with the connecting element (2) and the extrusion sleeve (3). 2. The connecting element system (1) according to claim 1, characterized in that the connecting element (2) has an engaging groove (10) and the holding element (4) has at least one connecting element-side engaging An element (14), the engaging element (14) on the connecting element side engages in the engaging 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 formed in a raised portion (9) on the connecting element (2), the raised A portion (9) forms an axial termination of said support body (6). 4. Connecting element system (1) according to any one of claims 1 to 3, characterized in that the retaining element (6) has an engagement element (16) on the side of a press sleeve, the press sleeve A lateral engagement element (16) engages with a cooperating receptacle (12) of the extrusion sleeve (3). 5 . The connecting element system ( 1 ) according to claim 1 , characterized in that the extrusion sleeve ( 3 ) consists 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 casing (15) for making the extrusion sleeve ( 3) Fastened on the support body (6) of the connection element (2). 7. 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), said pipe connection comprising: Pipe ends (7) of plastic pipes, plastic composite pipes or metal-plastic composite pipes; The connecting element system (1) according to any one of claims 1 to 6, wherein the support body (6) of the connecting element (2) is introduced into the pipe end (7); Squeeze sleeve (3); and an outer sleeve (15) fitted to the extrusion sleeve (3) to fasten the pipe end (7) to the support (6) of the connecting element (2) . 8 . The pipe connection ( 11 ) according to claim 7 , characterized in that the retaining element ( 4 ) has no radial contact with the extrusion sleeve ( 3 ) and/or the outer sleeve ( 14 ). 9. The pipe connection (11) according to claim 7 or claim 8, characterized in that the side of the engagement element (16) on the press sleeve side facing away from the support body (6) is at least partially substantially Runs parallel to the introduction bevel ( 20 ) of the jacket ( 15 ). 10. The pipe connection (11) according to any one of claims 7 to 9, characterized in that the coupling element (14) on the connecting element side is configured as a plurality along the inside of the retaining element (4). A single element arranged around. 11. The pipe connection (11) according to any one of claims 7 to 10, characterized in that the outer sleeve (15) is configured for axially sliding onto the extrusion sleeve (3) slip sleeve. 12. A method for establishing a pipe connection (11) according to any one of claims 7 to 11, wherein said method comprises the steps of: Pushing the overcoat (15) onto the plastic pipe, plastic composite pipe or metal-plastic composite pipe; introducing the support (6) of the connecting element (2) into the pipe end (7); as well as The sleeve ( 15 ) is pushed axially onto the press sleeve ( 3 ), whereby the tube end ( 7 ) is pressed onto the support ( 6 ) of the connecting element ( 2 ). 13. The method according to claim 11, characterized in that the extrusion sleeve (3) is pressed to the on the tube end (7), so that the engagement element (16) on the side of the extrusion sleeve has no contact point with the extrusion sleeve (3). 14. Method according to claim 12 or claim 13, characterized in that the casing (15) is axially pushed onto the The tube end (7), wherein a compression yoke (19) bears against the retaining element (6) during pushing on. 15. The method according to any one of claims 12 to 14, characterized in that, in the pipe connection (11), the outer diameter of the retaining element (4) corresponds substantially to the outer diameter of the outer sleeve (15 ) of the outer diameter.