Two-pipe system

Abstract

FIELD: pipelines.SUBSTANCE: two-pipe system with a primary pipeline carrying a medium and a secondary pipeline that is arranged around the primary pipeline for protection, comprising pipes and fittings of the primary pipeline, wherein the pipes and fittings of the primary pipeline are connected together and the pipes and fittings of the surrounding secondary pipeline, wherein the pipes of the secondary pipeline are made in the form of solid plastic pipes, and the fittings of the secondary pipeline are made in the form of half-shells, characterized in that the half-shells of the fittings and the adjacent pipes of the secondary pipeline are connected to each other by means of electrofusion couplings, or in that the half-shells of the fittings of the secondary pipeline and the adjacent fittings consisting of half-shells are connected to each other by means of electrofusion couplings, wherein at least one half-shell of the fitting has a seal extending along a branching plane that runs parallel to the axis, wherein the seal in the area of the electrofusion coupling forms a connection between the material and the half-shells of the fitting part or the half-shells and the electrofusion coupling.EFFECT: two-pipe system provides a high degree of flexibility in the configuration of the two-pipe system without the need to store a large number of different parts and provides easy access to the inner pipe and reliable connection technology.10 cl, 8 dwg

Description

[0001] The invention relates to a two-pipe system and a method for installing a system with a primary pipeline that conducts a carrier and a secondary pipeline that is located around the primary pipeline for protection, containing pipes and fittings for the primary pipeline, wherein the pipes and fittings for the primary pipeline are connected to each other and to the pipes and fittings of the surrounding secondary pipeline, wherein the pipes are made in the form of solid plastic pipes, and the fittings are made in the form of semi-shells.

[0002] Two-pipe systems are either required by law or installed by end users to prevent the unexpected release of hazardous chemicals into the environment or to prevent harm to personnel. Two-pipe systems are also used, in particular, to protect expensive systems (machines, information technology infrastructure). The secondary pipeline consists of a protective pipe that encloses the primary pipe internally or fluid-carrying. Secondary containment systems can be designed for either underground or aboveground installation, pressurized, or as a drainage system, and typically have some kind of leak detection system. Existing systems are connected via simultaneous or cascade welding. Connection technology varies significantly across continents.However, particularly in Europe, connections are increasingly being made using a thermal welding process (in the case of polyolefins).

[0003] The prior art teaches that prefabricated fittings are manufactured with an internal and external fitting element, which are then connected to the internal and external pipes in each case. Due to the large number of internal and external pipe diameters and various fitting elements, such as tees, elbows, and so on, which must be prefabricated, high inventory levels are required, which is currently undesirable. Secondary protective pipes are manufactured in a similar manner, with a smaller internal / primary pipe inserted into a larger external / protective pipe and equipped with a centering element. Connecting the pipes to the fittings in this case is the most challenging task. Existing systems require a significant number of simultaneous connections for installation.Typical adhesive bonded joints are made by first applying a base coat to both surfaces being fitted together. Cementite is then applied to both surfaces, and the fitted parts are then quickly joined with a quarter-turn twist. The parts are then held firmly for thirty seconds to a minute until the cementite sets. It should be understood that this method is even more challenging when attempting to create an internal and external joint simultaneously. To ensure full insertion of the coupling, twice as many surfaces must be prepared, and the internal pipe must be secured to the protective pipe. Furthermore, when performing a simultaneous joint, the internal joint is made "blind."Additional disadvantages of existing systems include the lack of ability to check the internal connection during pressure testing and the difficulty of locating and repairing a faulty connection if a leak occurs.

[0004] The object of the invention is to provide a two-pipe system and an associated method for installing it, which provides a high degree of flexibility in the configuration of the two-pipe system without the need to store a large number of different parts and provides easy access to the inner pipe and reliable connection technology.

[0005] According to the invention, this objective is achieved in that the half-shells of the fitting part and the adjacent pipes of the secondary pipeline are connected to each other by means of electrofusion couplings, and in that the electrofusion coupling, which is temporarily placed on the outer diameter of the pipe of the secondary pipeline, is partially pushed onto the fitting part, consisting of two half-shells, and welded, or in that the half-shells of the fitting parts and the adjacent fitting parts, consisting of half-shells, are connected to each other by means of electrofusion couplings.

[0006] A two-pipe system according to the invention with a primary pipeline carrying a medium and a secondary pipeline located around the primary pipeline for protection comprises pipes and fittings for the primary pipeline, wherein the pipes and fittings for the primary pipeline are preferably connected to each other by welding or by establishing an adhesive bond. The pipes and fittings for the primary pipeline are preferably made of plastic, but primary pipelines made of metal, which are surrounded by a secondary pipeline made of plastic, are also possible. Furthermore, the two-pipe system according to the invention comprises pipes and fittings for the surrounding secondary pipeline, wherein the pipes are made in the form of solid plastic pipes, and the fittings are made in the form of semi-shells.The half-shells of the fitting parts and the adjacent secondary pipeline pipes are connected to each other using electrofusion couplings. Similarly, the fitting parts adjacent to the fitting part are also connected to each other using electrofusion couplings.

[0007] It has been shown that an advantage is achieved if electrofusion couplings are designed as one-piece hollow cylindrical couplings. This allows the use of standard electrofusion couplings, which are temporarily slid onto the secondary pipeline pipe during assembly and, prior to welding, are preferably partially slid onto the fitting piece and then welded to the pipe and the fitting piece. The electrofusion couplings preferably have two heating elements, preferably heating wires, located on either side of the coupling and welded to the fitting piece and the secondary pipeline pipe.

[0008] Preferably, the half-shells are formed by a separation plane running through the center of the part for axial adjustment. In other words, the two half-shells are preferably symmetrical.

[0009] It is an advantage if the secondary pipeline fitting parts do not have heating elements, i.e. the half-shells do not have any heating elements.

[0010] As an additional advantageous embodiment, it has been shown that at least one half-shell of the secondary pipeline fitting component has a seal extending along the separation plane, wherein the seal in the area of ​​the electrofusion coupling or in the connecting portion creates a material connection with the half-shells of the fitting component after the electrofusion coupling is fixedly mounted on the secondary pipeline and welded. The seal extends along the edge or wall of the half-shell in the separation plane. The separation plane extends along the axis of the fitting component and divides this fitting component into two symmetrical half-shells. The seal preferably extends along the center of the edge.It has been shown that it is preferable for the seal to be placed in the region of the connecting part of the half-shells on the outer rim of the edge in such a way that the seal has direct contact with the electrofusion coupling and is connected to it by the connecting material when heated.

[0011] An advantage is achieved when the pipes and fittings of the primary pipeline are joined using electric welding. As a result, the same welding method can be used on both the primary and secondary pipelines. However, other joining methods, such as adhesive bonding or butt welding, are also possible for the primary pipeline.

[0012] Preferably, the primary piping system fitting parts are made of electric welded fitting parts.

[0013] The fittings are preferably made in the form of a tee, branch, and / or curved section. In other words, the tee, branch, and / or curved section of the secondary pipeline are formed as semi-shells and are welded together during assembly using an electrofusion coupling.

[0014] It is advantageous if the half-shells of the fitting part in each case have a connecting portion on the connection side, wherein the outside diameter of the connecting portions preferably corresponds to the outside diameter of the pipe. The connecting portions of the fitting part have an outside diameter smaller than the center region of the fitting part. As a result, the fitting part or the half-shell have a shoulder against which the electrofusion coupling rests during assembly, thereby specifying the exact position of the electrofusion coupling, or allowing the installer to determine how far the electrofusion coupling must be pushed onto the fitting part to ensure its proper installation. In the embodiment in which two fitting parts are welded together, it is advantageous if the fitting parts have markings on their connecting portions that indicate to the installer whether the electrofusion coupling is in the correct position.

[0015] It has been shown that an advantage is achieved when spacers are located in the fitting parts, whereby the spacers ensure a concentric arrangement of the primary and secondary pipelines. The primary and secondary pipelines are concentrically spaced apart using spacers. Furthermore, the spacer serves to axially position the fitting part relative to the primary pipeline.

[0016] The pipes are also preferably provided with spacer elements, and these spacer elements do not necessarily have to be identical to the elements of the fitting part.

[0017] As a preferred embodiment, the secondary pipeline fitting has at least one clamp, which clamp serves to temporarily secure the half-shells to the primary pipeline. This facilitates sliding the electrofusion coupling onto the secondary pipeline fitting. The clamp can be pre-attached to the half-shell as a separate component or molded into it during injection molding.

[0018] Another advantageous feature is that the spacer element already has the property of providing a certain degree of self-fixation on the primary pipeline, which also achieves the effect of temporarily fixing the part to fit the primary pipeline, so that the installer can more easily push on the electrofusion coupling because it does not need to be held tightly.

[0019] The method for installing a two-pipe system according to the invention includes the following steps:

[0020] welding a subsection of a primary pipeline with at least one fitting part and a pipe, wherein electric welding is preferably used to weld the fitting parts and pipes to the primary pipeline. Welding is performed in subsections to, on the one hand, test the weld and, on the other hand, attach or feed the secondary pipeline pipes in sections. The welding of the subsections of the primary pipeline is performed in such a way that a secondary pipeline pipe can be pushed onto at least one side of the primary pipeline.

[0021] In addition, electrofusion couplings are temporarily placed on the outside diameter of the secondary pipeline pipe, which is to be slid onto the primary pipeline. The secondary pipeline pipe, with the electrofusion coupling or the temporarily placed electrofusion couplings, is then slid onto the primary pipeline pipe, which has already been welded to the component, to ensure proper fit into the subassembly. After installation, the primary pipelines or subassemblies can be pressure tested and any leaks can be detected.

[0022] Next, the secondary pipeline fitting is attached, preferably around the primary pipeline fitting, by joining or connecting the two half-shells together. Naturally, it is also possible to attach a secondary pipeline fitting consisting of two half-shells to the primary pipeline pipe. This is typically done at the support points where the pipeline is secured. To weld the secondary pipeline, the electrofusion coupling, temporarily positioned on the secondary pipeline's outside diameter, is partially slid onto the secondary pipeline fitting consisting of two half-shells and welded. For the welding process, approximately half of the electrofusion coupling is positioned on the pipe's outside diameter and the other half on the fitting.

[0023] Preferably, the electrofusion coupling is pushed onto the connecting part of the secondary pipeline fitting or onto the two half-shells until it stops. Due to the larger cross-section, the stop is preferably located in the central area of ​​the fitting.

[0024] An exemplary embodiment of the invention is described with reference to the figures, and the invention is not limited to the exemplary embodiment. In the figures:

[0025] Fig. 1 shows a detail of a two-pipe system according to the invention with only one half-shell,

[0026] Fig. 2 shows a half-shell of a two-pipe system according to the invention,

[0027] Fig. 2a shows a half-shell of a two-pipe system according to the invention, in which in the area of ​​the connecting parts the seal is located on the outside,

[0028] Fig. 3 shows a part of a two-pipe system according to the invention,

[0029] Fig. 4-6 shows a method according to the invention for the step-by-step installation of a two-pipe system,

[0030] Fig. 7 shows a detail of the two-pipe system according to the invention, shown with only one half-shell with visible clamps and

[0031] Fig. 8 shows two fitting parts joined together using an electrofusion coupling.

[0032] The drawing shown in Fig. 1 shows a three-dimensional view of a partially welded fitting part 7 of a secondary pipeline 3, wherein the upper half-shell is not shown. The electrofusion coupling 9, shown on the right side, is already correctly positioned on the fitting part 7 and welded. However, the left and lower electrofusion coupling 9 still needs to be pushed onto the connecting part 13 of the fitting part 7. The two-pipe system 1 according to the invention has a primary pipeline 2 through which a medium circulates. The primary pipeline 2 contains pipes 4 and fitting parts 5, which are welded together preferably by means of electrofusion couplings 16, while other types of connection are also possible, such as, for example, establishing an adhesive bond and end welding. The primary pipeline 2 is preferably made of plastic, although a metal pipeline is also entirely possible for use as a primary pipeline.

[0033] Furthermore, the two-pipe system 1 according to the invention comprises a secondary pipeline 3, which is located around the primary pipeline system 2. The secondary pipeline 3 serves to protect the environment or to protect personnel from injury due to a leak of medium from the primary pipeline systems 2. The secondary pipeline 3 comprises pipes 6 and fitting parts 7, wherein the fitting parts 7 are made in the form of half-shells 8. The pipes 6 are made in the form of solid plastic pipes and are usually manufactured by an extrusion method. The pipes 6 are pushed over the pipe 4 of the primary pipeline 2, wherein only a subpart of the primary pipeline 2 is installed in order to then install the secondary pipeline 3. Two half-shells 8 of the fitting part 7 of the secondary pipeline 3 are fixed around a corresponding position of the primary pipeline 2. As a rule, this position also corresponds to the position of the fitting part 5 of the primary pipeline 2, as shown in Fig. 1.The half-shells 8 of the fitting parts 7 can also be attached in other positions, for example, where they serve as a support point 18 in which a two-pipe system 1 is attached, which can also be indicated in Fig. 3. For the concentric arrangement of the two pipelines 2, 3, the half-shells 8 have spacer elements 17, on which the fitting parts 5, 7 are concentrically spaced from each other. Additionally, the spacer elements serve for the axial positioning of the half-shells 8. In Fig. 1, the path of the seal 10, which runs along the edge or wall 12 of the half-shell 8, is clearly visible. When welding by means of electrofusion couplings 9 located on the parts 7 for fitting the secondary pipeline 3, the seal 10 is connected by connecting material to the half-shells 8 in the area of ​​the electrofusion couplings 9. In Fig. 2, the half-shell 8 of the part 7 for fitting the secondary pipeline 3 is shown.The connecting parts 13, onto which the electrofusion coupling 9 is pushed for welding the half-shells 8 or the fitting part 7, are clearly visible. The shoulder 15, which is formed due to the smaller diameter of the connecting part 13 relative to the central region 14 of the half-shell 8 or the fitting part 7, creates a stop for the electrofusion coupling 9, due to which the coupling is accordingly in the correct position. In addition, the path of the seal 10 along the edge 12 of the half-shell 8 is in turn clearly visible in Fig. 2. The seal 10 passes in the plane 11 of separation of the two half-shells 8, which form the fitting part 7. An exemplary embodiment, in which the seal 10 passes centrally along the entire edge of the half-shell 8, is shown in Fig. 2. An exemplary embodiment in which the seal 10 is located on the outside in the region of the connecting parts 13 on their outer diameter is shown in Fig.2a, so that when welded to the electrofusion coupling 9, it can be directly connected to it with a connecting material. Fig. 3 shows various fitting parts 7, which are designed in the form of half-shells 8. As an example, a tee is shown at an angle of 90°, while other fitting parts are also possible, such as branch parts, curved parts, or half-shells for fastening points, which are designed in the form of support points 18.

[0034] Figures 4-6 show a step-by-step installation method for a two-pipe system 1 according to the invention. Figure 4 shows a subsection of the primary pipeline 2 that has already been installed, preferably by welding pipes 4 and fitting parts 5, so that the pipe 6 of the secondary pipeline 3 can be pushed onto it. However, the sub-section of the primary pipeline 2 is welded in such a way that at least one side of the primary pipeline 2 remains available for sliding the secondary pipeline 3 onto it. In addition, Fig. 4 shows the preparation of the pipe 6 of the secondary pipeline 3 using an electrofusion coupling 9 temporarily placed on the outer diameter of the pipe 6, and then the pipe 6 and the electrofusion couplings 9 located on both sides of the pipe are pushed onto the sub-section of the primary pipeline 2. Fig. 5 shows how the pipe 6 with the electrofusion couplings 9 located on it is pushed onto the primary pipeline 2. In Fig.6 shows a pipe 6 of a secondary pipeline 2 pushed onto a fitting part 7. Then, electrofusion couplings 9 are pushed onto the connecting part 13 of the fitting part 7 up to the shoulder 15. Then, the electrofusion couplings 9 are welded. As a result, a two-pipe system 1 is formed, as shown in Fig. 3. Fig. 7 shows an open fitting part 7 of a secondary pipeline 3 or a half-shell 8 with a primary pipeline 2 passing through it. Clamps 18 are clearly visible, which are attached to them and which simply attach the half-shells 8 to the primary pipeline 3 for assembly. This provides the advantage of simply temporarily placing the half-shells 8 on the primary pipeline 2, which makes it easier for the installer to fasten the second half-shell and slide the electrofusion coupling 9.

[0035] Figure 8 shows an embodiment in which two fitting parts 7 of a secondary pipeline 3 are directly welded together without a pipe portion between them. Then, an electrofusion coupling 9 is installed in the center of the two connecting parts 13 of the fitting parts, and the axial position of the electrofusion coupling 9 is preferably determined in advance by markings on the fitting parts.

[0036] List of reference designations

[0037] 1 Two-pipe system

[0038] 2 Primary pipeline

[0039] 3 Secondary pipeline

[0040] 4 Primary pipeline pipes

[0041] 5 Primary Pipe Fitting Parts

[0042] 6 Secondary pipeline pipes

[0043] 7 Secondary Pipe Fitting Parts

[0044] 8 Half-shell

[0045] 9 Electrofusion coupling

[0046] 10 Seal

[0047] 11 Split plane

[0048] 12 Edge / wall of half shell

[0049] 13 Connecting part

[0050] 14 Central Region

[0051] 15 Ledge

[0052] 16 Electrofusion coupling - primary pipeline

[0053] 17 Spacer element

[0054] 18 Clamps.

Claims

1. A two-pipe system (1) with a primary pipeline (2) carrying a medium and a secondary pipeline (3) which is arranged around the primary pipeline (2) for protection, comprising pipes (4) and fittings (5) of the primary pipeline (2), wherein the pipes (4) and fittings (5) of the primary pipeline (2) are connected together, and pipes (6) and fittings (7) of the surrounding secondary pipeline (3), wherein the pipes (6) of the secondary pipeline (3) are made in the form of solid plastic pipes, and the fittings (7) of the secondary pipeline (3) are made in the form of half-shells (8), characterized in that the half-shells (8) of the fittings (7) and the adjacent pipes (6) of the secondary pipeline (3) are connected to each other by means of electrofusion couplings (9), or in that the half-shells (8) of the fittings (7) of the secondary pipeline (3) and the adjoining parts (7) for fitting, consisting of half-shells (8), are connected to each other by means of electrowelded couplings (9),wherein at least one half-shell (8) of the fitting part (7) has a seal (10) extending along the branching plane (11) extending parallel to the axis, wherein the seal (10) in the area of ​​the electrofusion coupling (9) forms a connection with the material of the half-shells (8) of the fitting part (7) or the half-shells (8) and the electrofusion coupling (9)., 2. A two-pipe system (1) according to claim 1, characterized in that the electrofusion couplings (9) are made in the form of solid hollow cylindrical couplings.

3. A two-pipe system (1) according to claim 1, characterized in that the half-shells (8) are formed by a separation plane passing through the center of the part (7) for adjustment along the axis.

4. A two-pipe system (1) according to one of paragraphs 1-3, characterized in that the pipes (4) and parts (5) for fitting the primary pipeline (2) are connected to each other using electric welding.

5. A two-pipe system (1) according to one of paragraphs 1-4, characterized in that the parts (5) for fitting the primary pipeline are made in the form of electrofusion couplings (16).

6. A two-pipe system (1) according to one of paragraphs 1-5, characterized in that the fitting parts (5, 7) are made in the form of a tee, a branch part and / or a curved part.

7. A two-pipe system (1) according to one of claims 1 to 6, characterized in that the half-shells (8) of the fitting part in each case have a connecting part (13) on the connection side, wherein the outer diameter of the connecting parts (13) preferably corresponds to the outer diameter of the pipe (6).

8. A two-pipe system (1) according to one of claims 1-7, characterized in that the spacer elements (17) are located in the parts (7) for adjustment, and the spacer elements (17) ensure a concentric arrangement of the primary pipeline and the secondary pipeline in relation to each other.

9. A two-pipe system (1) according to one of claims 1-8, characterized in that at least one clamp (18) is located in the parts (7) for fitting for temporary fastening of the half-shells (8) to the primary pipeline (2).

10. A method for installing a two-pipe system according to one of paragraphs 1-9, which includes the following steps: welding a sub-part of the primary pipeline (2) to at least one fitting part (5) and to at least one pipe (4), temporary placement of an electric welding coupling (9) on the outer diameter of the pipe (6) of the secondary pipeline (3), which must be pushed onto the primary pipeline (2), sliding the pipe (6) with the electric-welded coupling (9) of the secondary pipeline (3), temporarily placed on it, onto the pipeline part of the sub-part of the primary pipeline (2), welded to the part (5) for fitting, fastening the part (7) for fitting the secondary pipeline (3), preferably around the part (5) for fitting the primary pipeline (2), by joining two half-shells (8), characterized in that the electrofusion coupling (9), which is temporarily placed on the outer diameter of the pipe (6) of the secondary pipeline (3), is partially pushed onto the fitting part (7), consisting of two half-shells (8), and welded.

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