CONNECTING ELEMENT AS WELL AS THIS COMPREHENSIVE PIPE CONNECTION

Description

[0001] The present invention relates to a connecting element for producing a pipe connection between the connecting element and a plastic pipe or a metal-plastic composite pipe, wherein the connecting element has at least one support body provided with several circumferential external ribs for sliding a pipe end onto it, wherein the at least one support body has a central axis and an open end, and at least two circumferential external ribs are inclined at an acute angle to the central axis. Furthermore, the present invention relates to a pipe connection between an end of a solid plastic pipe or a plastic composite pipe and a connecting element, wherein the pipe connection comprises an end of a solid plastic pipe or a plastic composite pipe and such a connecting element.

[0002] Such connecting elements and this comprehensive pipe connection are known from the prior art. The pipe end is fixed to the connecting element by means of a fixing sleeve arranged above the pipe end, through which the pipe end is pressed against the outer contour of the support body, which is provided with circumferential external ribs. Depending on the method of application of the fixing sleeve used, different types of connection techniques are distinguished. In sliding sleeve connections, which are also referred to as axial press connections, the support body of the connecting element is inserted into a flared or unflared pipe end, and a sliding sleeve located on the outside of the pipe end is pushed axially onto the pipe end with the inserted support body of the connecting element by means of a special sliding tool. Such an axial press system with a sliding sleeve is described, for example, in DE 101 30 858 A1.In radial press fittings, the press sleeve is first pushed onto the plastic pipe to be joined. Then, the support body, which can be made of metal or a plastic material, is inserted into the pipe end. The press sleeve is positioned over the support sleeve on the pipe end and finally pressed radially onto the pipe end using appropriate pressing tools, thereby deforming it mechanically and irreversibly. The support body can be made of metal, for example, dezincification-resistant brass or stainless steel, or of a hydrolysis-resistant polymer material such as polysulfone (PSU), polyethersulfone (PES), or polyphenylsulfone (PPSU).

[0003] Especially with mechanical pipe connections where the pipe end to be attached to the support body is not flared, the dimensions of the individual components must be coordinated. In particular, the outer diameter of the connector and the inner diameter of the pipe must be selected so that the connector can be easily inserted into the pipe end, but does not fall out of the pipe under its own weight. Furthermore, cutting, especially of metal-plastic composite pipes, can create a burr that further complicates the insertion of a connector into the cut pipe end. Additionally, cutting the pipe can also negatively affect the insertion of the connector into the pipe end, as any ovality of the pipe can be further exacerbated by the action of pipe shears.For these reasons, it is usually necessary to calibrate the pipe with a special tool before inserting the connecting element or sliding it onto the support body of the connecting element, so that the ovality of the pipe is reduced and, if necessary, any burr that may be present is also removed by chamfering the pipe end.

[0004] Such connecting elements and this comprehensive pipe connection are known, for example, from DE 10 2010 053 006 A1, EP 1 953 441 A2, ES 2 302 653 A1, WO 2007 / 045033 A1 and DE 20 2015 106 955 U1.

[0005] Against this background, the object of the present invention is to provide a connecting element and a pipe connection comprising it that overcome the disadvantages of the prior art. In particular, the connecting element according to the invention should be easier to insert into a pipe end, thereby potentially eliminating the need for pipe calibration.

[0006] These and other problems are solved according to the present invention by a connecting element with the features of claim 1 and a pipe connection with the features of claim 12. Preferred embodiments of the connecting element and the pipe connection according to the invention are described in the dependent claims.

[0007] According to the present invention, it has been found that circumferential outer ribs inclined at an acute angle to the central axis of the support body have a positive effect on the insertion of the support body into a pipe end. This effect is particularly pronounced at very shallow angles of inclination. However, due to the length of the circumferential outer ribs resulting from these very shallow angles of inclination, the radial force transmitted by the fixing sleeve is distributed over a larger area, which can impair the stability of the resulting pipe connection. This can be counteracted by having the support body of the connecting element include at least one further circumferential outer rib with a steeper angle of inclination. With such circumferential outer ribs at a steeper angle of inclination, the radial force transmitted by the fixing sleeve acts over a smaller area, thereby improving the stability of the pipe connection.Furthermore, the ovality of the pipe end, which can occur, for example, when the pipe is cut to length, can be reduced by circumferential external ribs with varying angles of inclination when sliding the end onto the support body of the connecting element. Even a burr that may be present on the pipe end, caused by the cutting tool when the pipe is cut, hardly affects the insertion of the support body with such circumferential external ribs into the pipe end. Therefore, the additional step of pipe calibration becomes unnecessary when using such a connecting element.

[0008] Accordingly, the present invention lies in providing a connecting element for producing a pipe connection between the connecting element and a plastic pipe or a metal-plastic composite pipe, wherein the connecting element has at least one support body provided with several circumferential outer ribs for sliding on a pipe end, wherein the at least one support body has a central axis and an open end, and at least two circumferential outer ribs are inclined at an acute angle to the central axis, wherein the connecting element is characterized according to the invention in that the acute angle at which the circumferential outer rib is inclined to the central axis differs from the acute angle at which at least one of the circumferential outer ribs, which is further apart from the open end than the first-mentioned circumferential outer rib, is inclined to the central axis, wherein the acute angles,the respective outer rib is inclined towards the central axis, increasing steadily from the open end. Furthermore, the present invention relates to a pipe connection between an end of a solid plastic pipe or a plastic composite pipe and a connecting element, which comprises a pipe end of a solid plastic pipe or a plastic composite pipe and a connecting element according to the invention.

[0009] With regard to the connecting element according to the invention, it can be advantageous if the acute angle at which the circumferential outer rib is inclined to the central axis is smaller than the acute angle at which at least one of the circumferential outer ribs, which is further away from the open end than the first circumferential outer rib, is inclined to the central axis. This contributes to a greater reduction in the ovality of the cut-off pipe end. For this purpose, it is particularly preferred if the angle of inclination of the circumferential outer ribs increases starting from the open end of the support body.

[0010] It can also prove helpful if the difference between the acute angle at which the circumferential outer rib is inclined to the central axis and the acute angle at which at least one of the circumferential outer ribs, which is further away from the open end than the circumferential outer rib, is inclined to the central axis, lies in a range of 3° to 20°, preferably in a range of 5° to 15°, and particularly preferably in a range of 8° to 12°. At inclination angles in these ranges, a balanced relationship is achieved between the ease of insertion of the support body of the connecting element according to the invention and the stability of the pipe connection.

[0011] It can also be advantageous if the support body comprises at least one circumferential outer rib with a substantially rectangular cross-section. Such circumferential outer ribs with a substantially rectangular cross-section are less susceptible to drop impact damage. Since such rectangular ribs can negatively affect the slideability of the pipe end, it is preferred if, on the side facing the open end of the support body and / or on the side facing away from the open end of the support body, at least one circumferential outer rib with a substantially rectangular cross-section is arranged, inclined at an acute angle to the central axis. In this context, it is particularly preferred if the circumferential outer ribs with a substantially rectangular cross-section have a smaller outer diameter than the outer ribs inclined at an acute angle to the central axis.This ensures that the pipe can be easily slid onto the support body of the connecting element according to the invention, with the reduced diameter of the circumferential outer ribs, which have a substantially rectangular cross-section, guaranteeing a sealing effect on all circumferential outer ribs when pressed in. It is particularly preferred that the inclined circumferential outer ribs have a steep angle of inclination, preferably in the range of 15° to 50°. This allows the inclined circumferential outer ribs to engage deeply into the pipe material and ensure a high degree of tightness of the resulting pipe connection. In further preferred embodiments, a circumferential outer rib with a substantially rectangular cross-section is the outer rib furthest from the open end of the support body.In particularly preferred embodiments, the circumferential outer ribs with a substantially rectangular cross-section can also be the circumferential outer ribs furthest from the open end of the support body. In this case, the circumferential outer ribs can also have the same outer diameter as the inclined circumferential outer ribs. When the support body is inserted into the pipe end, any burr that may occur is already leveled by the inclined circumferential outer ribs, so that the insertion of the support body into the pipe end is no longer impeded.

[0012] It can also be advantageous if the connecting element further comprises at least one circumferential collar. Such a circumferential collar serves as a point of engagement for a pressing tool when creating the pipe connection according to the invention.

[0013] It can also be advantageous if the connecting element is designed as a polymer component or a metallic component. It has proven particularly beneficial if the polymer material of the connecting element is selected from the group consisting of polypropylene (PP), polyamides, polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PSU), polyphenylsulfone (PPSU), polyphenylene sulfide (PPS), polyvinyl chloride (PVC), polyoxymethylene (POM), acrylonitrile butadiene styrene copolymer (ABS), and polyester carbonate (PESC), as well as copolymers and blends of these polymers, each also in fiber-reinforced form. Alternatively, metallic materials such as brass, especially Ecobrass®, red brass, and stainless steel can also be used.

[0014] With regard to the pipe connection according to the invention, it may be preferred if the pipe connection is designed as an axial press connection with a sliding sleeve. The high stability of the connecting element according to the invention is particularly suitable for such an axial press connection, in the manufacture of which high axial forces act, especially on the circumferential collar. In axial press systems where the pipe end is not expanded before the insertion of the support body, it is particularly advantageous that any burr formed when cutting the pipe is leveled out again by the circumferential outer ribs with different angles of inclination.

[0015] According to the present invention, the plastic pipes used are solid plastic pipes, preferably made of polyethylene (PE, in particular PE 100 and PE-RT), cross-linked polyethylene (PE-X, in particular PE-Xa, PE-Xb and PE-Xc), polypropylene (in particular statistical polypropylene PP-R) and polybutylene (PB); as well as composite plastic pipes, preferably with layers of polyethylene (PE, in particular PE 100 and PE-RT), cross-linked polyethylene (PE-X, in particular PE-Xa, PE-Xb and PE-Xc), polypropylene (in particular statistical polypropylene PP-R), and / or polybutylene (PB). An additional layer of ethylene-vinyl alcohol copolymer (EVOH) can be present as an oxygen barrier.Metal-plastic composite pipes (MKV pipes) according to the present invention preferably comprise layers of polyethylene (PE, in particular PE 100 and PE-RT), cross-linked polyethylene (PE-X, in particular PE-Xa, PE-Xb and PE-Xc), polypropylene (in particular static polypropylene PP-R) and / or polybutylene (PB) and at least one layer of metals, preferably aluminum. The metal layer is preferably butt-welded. In the case of plastic composite pipes and MKV pipes, adhesion promoter layers may be incorporated between individual layers. According to the present invention, all pipes of a pipe connection according to the invention may have an identical structure, or one or more of the pipes may have different pipe structures. Furthermore, the pipes according to the present invention may also be fiber-reinforced. The fiber reinforcement of the pipes may be present in individual or all pipes, over the entire pipe length or only in sections.With regard to the plastic pipe or the metal-plastic composite pipe of the pipe connection according to the invention, it is particularly preferred that at least one layer of the respective pipe comprises cross-linked polyethylene (in particular PE-Xa, PE-Xb and PE-Xc). The material "cross-linked polyethylene" is a material that possesses a shape memory or a so-called "memory effect". This memory effect lies in the fact that the cross-linked polyethylene, after a change in its external geometry, attempts to return to its original shape. When pipes are expanded, this means that a PE-X-encompassing pipe, after expansion, attempts to regain its original inner diameter.Since a support body of a connecting element is inserted into the expanded pipe end after the expansion, the memory effect when using a pipe that comprises at least one layer of cross-linked polyethylene leads to a particularly high tightness of the pipe connection according to the invention.

[0016] The connecting element according to the invention can be a threaded component or a threadless component, i.e., a connecting element that does not have a thread. This includes, in particular, connectors, elbows, manifolds, tees, wall tees, wall elbows, system transitions, adapters, and angled adapters, each of which does not have a thread. Accordingly, the term "threaded component" refers to a connecting element that has at least one threaded component. This includes, in particular, connectors, elbows, manifolds, tees, wall tees, wall elbows, system transitions, adapters, and angled adapters, each of which has at least one internal and / or external thread.

[0017] According to the invention, suitable materials for the sliding sleeve include preferably polymeric materials such as polypropylene and glass fiber-reinforced polypropylene, polyamides and glass fiber-reinforced polyamides, temperature-resistant thermoplastics such as polyphenylsulfone (PPSU), polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PSU), polyphenylene sulfide (PPS), acrylonitrile butadiene styrene copolymer (ABS), and polyester carbonate (PESC), as well as copolymers and blends of these polymers, wherein these polymer materials can also be fiber-reinforced, in particular glass fiber-reinforced, and metallic materials such as brass, in particular Ecobrass®, red brass, and stainless steel. Temperature-resistant plastics, and in particular polyphenylsulfone and polyvinylidene fluoride, are especially preferred as materials for the sliding sleeve. Cross-linked polyethylene (in particular PE-Xa, PE-Xb, and PE-Xc) is also particularly preferred as a material for the sliding sleeve.

[0018] The pipe connection according to the present invention is used in particular in piping and connection systems in drinking water installations, in sprinkler systems, in radiator connections, in concrete core activation systems and in surface heating and / or surface cooling systems.

[0019] The pipe connection arrangement according to the invention, as well as individual parts thereof, in particular the connecting element according to the invention, can be manufactured, for example, line by line or layer by layer using a line-by-line or layer-by-layer manufacturing process (e.g., 3D printing). Preferably, however, the connecting element according to the invention is manufactured using an injection molding process.

[0020] The invention will now be explained in detail with reference to the embodiments illustrated in the figures. These figures show: Fig. 1 a cross-sectional view of a connecting element according to an embodiment of the present invention; Fig. 2 a cross-sectional view of a connecting element according to a further embodiment of the present invention; and Fig. 3 a cross-sectional view of a pipe connection according to an embodiment of the present invention.

[0021] In Fig. 1 A connecting element 1 according to the invention for producing a pipe connection between the connecting element 1 and a plastic pipe or a metal-plastic composite pipe according to an embodiment of the present invention is shown in a cross-sectional view. The connecting element 1 according to the invention is a connector with two support bodies 2, 2a. The connecting element 1 is shown in the Fig. 1 The embodiment shown is designed as a one-piece plastic component made of glass fiber reinforced polyphenylsulfone (PPSU). The structure of the connecting element 1 according to the invention is described below with reference to the one shown in Fig. 1 left support body 2 is described in detail, whereby it is understood that these descriptions apply to the one in Fig. 1 The right support body 2a and any further support bodies that may be present in other embodiments apply accordingly. In the Fig. 1 In the embodiment shown, the support body 2 has four circumferential outer ribs 3, 3a, 3b, 3c. On their inner surface, the support body 2 has a substantially cylindrical inner surface with a common central axis 4. The support body 2 is terminated by a circumferential collar 5. The two support bodies 2, 2a are connected to each other via a connecting area 6. Furthermore, the two support bodies 2, 2a together with the connecting area 6 form a connecting channel 7 through which a medium can flow during operation of the connecting element 1 according to the invention.

[0022] The four circumferential outer ribs 3, 3a, 3b, 3c have a sawtooth cross-section. The side of the circumferential outer ribs 3, 3a, 3b, 3c facing the open end 8 is inclined at an acute angle 9, 9a, 9b, 9c to the central axis 4. The side of the circumferential outer ribs 3, 3a, 3b, 3c facing away from the open end 8 forms a right angle with the central axis 4, with the transitions to the side facing the open end 8 and to the base region of the support body 2, 2a being rounded. The acute angle 9 of the circumferential outer rib 3 is 7°, the acute angle 9a of the circumferential outer rib 3a is 15°, the acute angle 9b of the circumferential outer rib 3b is 20°, and the acute angle 9c of the circumferential outer rib 3a is 30°. Thus, the acute angles 9, 9a, 9b, 9c, at which the respective outer rib 3, 3a, 3b, 3c is inclined to the central axis 4, increase continuously from the open end 5.This significantly reduces the ovality that arises when the pipe is cut to length and the pipe end is pushed onto the support body 2, 2a of the connecting element 1 according to the invention. This eliminates the need for the additional step of pipe calibration when using a connecting element 1 according to the invention.

[0023] The ends of identical or different plastic pipes or metal-plastic composite pipes can be connected to the two support bodies 2, 2a in a pipe connection according to the invention.

[0024] In Fig. 2 Another embodiment of the connecting element 1 according to the invention is shown. To avoid repetition, only differences from the one in [reference to be added] are discussed below. Fig. 1 The illustrated embodiment of the connecting element 1 according to the invention is described. The explanations regarding Fig. 1 also apply to the design of the Figur 2 Accordingly. Identical elements are indicated in the illustrations by identical reference symbols.

[0025] In Fig. 2 Another embodiment of the connecting element 1 according to the invention is shown again in a cross-sectional view. The Fig. 2 The connecting element 1 shown according to the invention differs from the one shown in Fig. 1 The illustrated embodiment differs only with regard to the design of the circumferential outer ribs. In the connecting element 1 according to the invention Fig. 2 The circumferential outer rib 3 adjacent to the open end 4 is designed as a sawtooth-shaped outer rib, wherein the acute angle 9 at which the circumferential outer rib 3 is inclined to the central axis 4 is 15°. Two circumferential outer ribs 10, 10a with substantially rectangular cross-sections adjoin this. A further circumferential outer rib 3a is arranged between the circumferential outer rib 10a and the circumferential collar 5, wherein the acute angle 9a at which the circumferential outer rib 3a is inclined to the central axis 4 is, in the embodiment according to Fig. 2 The angle is 20°. The steep inclination of the circumferential outer ribs 3, 3a causes them to engage deeply in the pipe material, resulting in a high degree of tightness in the pipe connection. The circumferential outer ribs 10, 10a have a smaller outer diameter than the circumferential outer ribs 3, 3a, which are inclined at an acute angle to the central axis 4. This ensures that the pipe can be easily slid onto the support body 2, 2a of the connecting element 1 according to the invention. The circumferential outer ribs 10, 10a, with their substantially rectangular cross-section, also make the connecting element 1 according to the invention less susceptible to impact damage. Furthermore, the connecting element 1 is in the Fig. 2 The illustrated embodiment is designed as a one-piece plastic component made of glass fiber reinforced polyphenylsulfone (PPSU).

[0026] Fig. 3 Finally, one shows the connecting element 1 according to the invention. Fig. 1 A comprehensive pipe connection 11, which in the illustrated embodiment is designed as a sliding sleeve connection, is shown in a cross-sectional view, with the connection of a pipe 12 only at the support body 2a. A sliding sleeve 13 is pressed axially onto the expanded end 14 of a plastic pipe 12, which is pushed onto the support body 2a and is pushed almost to the circumferential collar 5a of the support body 2a of the connecting element 1 according to the invention.

[0027] To produce the pipe connection 11 according to the invention, the sliding sleeve 13 is first pushed over the end 14 of the plastic pipe 12. Then, an expanding tool is inserted into the end 14 of the plastic pipe 12, and the end of the plastic pipe 12 is expanded using this tool. Subsequently, the support body 2a of the connecting element 1 according to the invention is inserted into the expanded end 14 of the plastic pipe 12 until the expanded end 14 of the plastic pipe 12 is almost abutting the circumferential collar 5a. Finally, the sliding sleeve 13 is pushed axially onto the expanded end 14 of the plastic pipe 12 with the inserted support body 2a using a suitable sliding tool. In this process, the plastic material of the plastic pipe 12 is pressed into the outer contour of the support body 2a of the connecting element 1 according to the invention.

[0028] In alternative embodiments, the pipe connection 1 according to the invention can also be an axial press connection with a sliding sleeve 13, in which the end 14 of the plastic pipe 12 is not expanded. In the manufacture of the pipe connection 1 according to the invention, the stage of expanding the pipe end 12 is then omitted.

[0029] The present invention has been described in detail with reference to the embodiments of the present invention shown in the figures. It is understood that the present invention is not limited to the embodiments shown, but that the scope of the present invention is defined by the accompanying claims.

Claims

1. A connecting element (1) for producing a pipe connection (11) between the connecting element (1) and a plastic pipe (12) or a metal-plastic composite pipe (12), wherein the connecting element (1) comprises at least one support body (2, 2a) provided with a plurality of circumferential outer ribs (3, 3a, 3b, 3c) for sliding a pipe end (14) thereonto, wherein the at least one support body (2, 2a) has a central axis (4) and an open end (8), and wherein at least two circumferential outer ribs (3, 3a, 3b, 3c) are inclined at an acute angle (9, 9a, 9b, 9c) relative to the central axis (4), wherein the acute angle (9, 9a, 9b) at which the circumferential outer rib (3, 3a, 3b) is inclined relative to the central axis (4) differs from the acute angle (9a, 9b, 9c) at which at least one of the circumferential outer ribs (3a, 3b, 3c), which is spaced farther from the open end (8) than the circumferential outer rib (3, 3a, 3b), is inclined relative to the central axis (4), and wherein the acute angles (9, 9a, 9b, 9c) at which the respective outer rib (3, 3a, 3b, 3c) is inclined relative to the central axis (4) continuously increase starting from the open end (5).

2. The connecting element (1) according to claim 1, characterized in that the acute angle (9, 9a, 9b) at which the circumferential outer rib (3, 3a, 3b) is inclined relative to the central axis (4) is smaller than the acute angle (9a, 9b, 9c) at which at least one of the circumferential outer ribs (3a, 3b, 3c), which is spaced farther from the open end (8) than the circumferential outer rib (3, 3a, 3b), is inclined relative to the central axis (4).

3. The connecting element (1) according to claim 1 or claim 2, characterized in that the difference between the acute angle (9, 9a, 9b) at which the circumferential outer rib (3, 3a, 3b) is inclined relative to the central axis (4) and the acute angle (9a, 9b, 9c) at which at least one of the circumferential outer ribs (3a, 3b, 3c), which is spaced farther from the open end (8) than the circumferential outer rib (3, 3a, 3b), is inclined relative to the central axis (4), lies within a range of 3° to 20°.

4. The connecting element (1) according to one of the preceding claims, characterized in that the sides of the circumferential outer ribs (3, 3a, 3b, 3c) facing the open end (8) of the support body (2, 2a) are inclined at the acute angle (9, 9a, 9b, 9c) relative to the central axis (4).

5. The connecting element (1) according to one of the preceding claims, characterized in that the support body (2, 2a) comprises at least one circumferential outer rib (10, 10a) having a substantially rectangular cross-section.

6. The connecting element (1) according to claim 5, characterized in that at least one circumferential outer rib (3, 3a, 3b, 3c), which is inclined at an acute angle (9, 9a, 9b, 9c) relative to the central axis (4), is arranged both on the side of the at least one circumferential outer rib (10, 10a) having a substantially rectangular cross-section facing the open end (8) of the support body (2, 2a) and on the side facing away from the open end (8) of the support body (2, 2a).

7. The connecting element (1) according to claim 5 or claim 6, characterized in that a circumferential outer rib (10, 10a) having a substantially rectangular cross-section constitutes the outer rib spaced farthest from the open end (8) of the support body.

8. The connecting element (1) according to one of claims 5 to 7, characterized in that the circumferential outer ribs (10, 10a) having a substantially rectangular cross-section have a smaller outer diameter than the outer ribs (3, 3a, 3b, 3c) which are inclined at an acute angle (9, 9a, 9b, 9c) relative to the central axis (4).

9. The connecting element (1) according to one of the preceding claims, characterized in that it further comprises at least one circumferential collar (5, 5a) which forms the termination of the support body (2, 2a).

10. The connecting element (1) according to one of the preceding claims, characterized in that the connecting element (1) is designed as a polymer component.

11. The connecting element (1) according to one of the preceding claims, characterized in that the polymer material of the connecting element (1) is selected from the group consisting of polypropylene (PP), polyamides, polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PSU), polyphenylsulfone (PPSU), polyphenylene sulfide (PPS), polyvinyl chloride (PVC), polyoxymethylene (POM), acrylonitrile-butadiene-styrene copolymer (ABS), and polyester carbonate (PESC), as well as copolymers and blends of these polymers, each also in fiber-reinforced form.

12. A pipe connection (11) between an end (14) of a plastic pipe (12) or a metal-plastic composite pipe (12) and a connecting element (1), comprising: an end (14) of the plastic pipe (12) or the metal-plastic composite pipe (12); and a connecting element (1) according to one of claims 1 to 11.

13. The pipe connection (12) according to claim 12, characterized in that the pipe connection (12) is designed as an axial press connection with a sliding sleeve (13).