WO1991014898A1

WO1991014898A1 - Preinsulated socket pipe element

Info

Publication number: WO1991014898A1
Application number: PCT/FI1991/000079
Authority: WO
Inventors: Stefan Lindvall
Original assignee: Oy Muotekno Ab
Priority date: 1990-03-28
Filing date: 1991-03-25
Publication date: 1991-10-03
Also published as: FI84295C; FI84295B; FI901561A; FI901561A0

Abstract

The present invention is related to a preinsulated socket pipe element, which has a flow pipe (2) provided with at least one socketed end (1), an insulation layer (3) of hard foamed plastic as well as an outer protective cover (4), and a conduit (5) drawn mainly axially through the insulation layer (3) in the vicinity of the flow pipe (2) for a cable (6), whereby the protective cover (4) and the insulation layer (3) at the socketed end (1) terminate exactly on the end level of the flow pipe (2) and at the non-socketed end (7) as a uniform radial surface mainly at a distance corresponding to the length of the socket joint from the end of the flow pipe. The invention is mainly characterized in that the insulation layer (3) of the socketed end (1) has a circular groove (8) surrounding the flow pipe (2), the width and depth of the groove corresponding at least to the cross-section of the cable conduit (5).

Description

Preinsulated socket pipe element

The present invention is related to a preinsulated socket pipe element, which has a flow pipe provided with at least one socketed end, an insulation layer of hard foamed plas¬ tic as well as an outer protective cover, and a conduit drawn mainly axially through the insulation layer in the vicinity of the flow pipe for a cable, whereby the protec¬ tive cover and the insulation layer at the socketed end terminate exactly on the end level of the flow pipe and at the non-socketed end as a uniform radial surface mainly at a distance corresponding to the length of the socket joint from the end of the flow pipe.

Preinsulated socket pipe elements designed for light muni¬ cipal engineering prevent water and drain pipes installed on frost susceptible ground from freezing. Owing to this, it is not necessary to install the pipe under the frost limit, whereby earth excavating or ground breaking can be reduced by about 50-75%.

Either a pipe heating cable or a moisture/leakage alarm cable can be threaded through a cable conduit in the socket pipe element. A pipe heating cable is used for example if the pipeline is drawn totally above the ground or only slightly excavated through the ground or if it must be ensured that the pipeline remains in a molten state even during the most severe wintertime. In industrial areas and also in other places where insulated pipelines are used for transporting materials dangerous for the environment or where the pipeline is drawn through a moisture sensitive area, a moisture or leakage alarm cable can be threaded through the cable conduit of socket pipe elements, the current carrying capacity of which cable changes when it comes into contact with the material led through the flow pipe or with external liquid or water penetrated through a damaged shield extension. Owing to the cable conduit, the installation or changing of the pipe heating cable or alarm cable can be performed during the usage without having to excavate the pipes to view along long distances.

When two preinsulated socket pipe elements are joined together, an elastic ring of polyethylene cellular plastic is first threaded around the bare non-socketed end of the flow pipe, and after this, this non-socketed end is pushed into the socketed end of another socket pipe element, whereby the joint is complete. If the pipe is provided with a heating or alarm cable, this can be readily installed in connection with the joining-together of the socket pipe elements.

When two straight preinsulated socket pipe elements are joined together, there are no problems whatsoever to fit the cable conduits in the insulation layer of the elements together, but immediately when a branch or angle piece must be joined to the pipeline, it is not possible to know for certain beforehand the final position of the branch or angle piece. If the angle or branch piece is intended to deviate or branch to the right and the pipeline in the place concerned turns or branches in fact to the left, the cable conduit of the angle or branch piece does not fit together with the cable conduit of the previous plastic pipe element. Because of this, different branch or angle pieces must be manufactured for example for a pipeline branching or turning to the right, to the left, upwards or downwards, which makes the storage maintenance and the making of orders more difficult.

The object of the present invention is to eliminate even this problem, which has been achieved by means of a prein¬ sulated socket pipe element, characterized in that the insulation layer of the socketed end has a circular groove surrounding the flow pipe, the width and depth of which groove correspond to at least the cross-section of the cable conduit. Owing to this groove, the socket pipe ele¬ ments to be joined together can be turned in connection with the installation with respect to each other into a position required by the ground without the cable conduits preventing this from occurring. The pipe heating or alarm cable installed in the cable conduit is namely placed in connection with the turning in the circular groove located at the socketed end. At the same time, it is also not necessary to use more than one branch, T- or angle piece for one pipe size.

The remaining characteristics of the present invention are given in the enclosed claims.

The invention is next explained in more detail with refe¬ rence to the accompanying drawing, in which

Fig. 1 shows a straight preinsulated socket pipe element according to the invention as a side view,

Fig. la is an end view of the socketed end of the socket pipe element of Fig. 1,

Fig. 2 shows a branch piece according to the invention,

Fig. 3 shows a center section of the branch piece of Fig. 2,

Fig. 4 shows an angle piece according to the invention, and

Fig. 5 shows the connection of two socket pipe elements.

The preinsulated socket pipe element according to the invention comprises a flow pipe 2 provided with at least one socketed end 1 and made of plastic or metal, an insula- tion layer 3 of hard foamed plastic, like polyurethane or phenol, as well as an external protective cover 4. The protective cover 4 may be made of plastic, such as thermal¬ ly stabilized PEH-plastic or metal. The insulation layer 3 can preferably be a blind-cell and preferably a freon-free polyurethane foam. Such an insulation layer 3 has excellent insulation properties and it is mechanically rigid and simultaneously prevents the absorption of water into the insulation. Through the insulation layer 3, exactly in the vicinity of the flow pipe 2 is arranged an axially directed conduit 5 for a cable 6. This cable may be either a pipe heating cable or a moisture/leakage alarm cable. At the socketed end 1 of the socket pipe element, the insulation layer 3 and the protective cover 4 end on exactly the end level of the flow pipe 2, and at the non-socketed end 7, the insulation layer 3 and the protective cover 4 end as a uniform radial surface mainly at a distance corresponding to the length of the socket joint from the end of the flow pipe 2. The socket pipe element according to the invention is characterized in that the insulation layer 3 of its socketed end 1 has a circular groove 8 surrounding the flow pipe 2, the witdh and depth of the groove corresponding at least to the cross-section of the cable conduit 5, at which groove 8 the cable conduit 5 ends.

Owing to the groove 8, the socket pipe elements can be arbitrarily turned in connection with the joining-together around their axes without the fact that the cable 6 drawn through the cable conduit 5 prevents this. Because of this, only a T-piece of one type, an angle piece of one type and a branch piece of one type are needed for one pipe dimensi¬ on, whereby stocking is essentially facilitated.

The socket pipe element may be a straight pipe, whose one end 1 is socketed, as shown in Fig. 1 and la, a T-piece, whose all ends are socketed, as shown in Fig. 2 and 3, a branch piece having two socketed ends 1 and one non-socke- ted end 7, not shown, a pipe bend, whose one end 1 is socketed and whose other end 7 is non-socketed, as shown in Fig. 4, or whose both ends 1 are socketed, or possibly a shrink piece, whose one end 1 is socketed and whose other end 7 is non-socketed.

The principle of the joining-together of the socket pipe elements is shown in Fig. 5. When the cable 6 is drawn through the cable conduit 5 of the socket pipe element, whose non-socketed end 7 in turn joins the next socket pipe element to the socketed end 1, the cable is threaded through a flexible ring 9 made of PE cellular plastic, which ring is then pushed into the end of the bare flow pipe 2 of the non-socketed end 7. There is preferably inside the flexible ring 9 a small notch for the cable 6. The cable 6 is then threaded into the cable conduit 5 of the next socket pipe element from the socketed end 1 of the element, after which both elements are pushed together so that the bare flow pipe 2 of the non-socketed end 7 is pushed into the socketed end 1 of the next element, whereby the flexible ring 9 forms a sealing between the insulation layer of two elements. The connected elements can then be turned around their axis into the desired position, whereby the cable 6 slides in the cable conduit 6 and in the groove 8 to the desired extent and it does not thus prevent the mutual turning movement of the elements.

The inventive socket pipe elements can preferably be utili¬ zed for example in new constructions of light municipal engineering, in water and drain networks of industrial areas, in bridge constructions, as temporary pipelines, in pipe networks of holiday resorts and in the renewal of old pipes.

Claims

Claims :

1. A preinsulated socket pipe element having a flow pipe (2) provided with at least one socketed end (1), an insula- tion layer (3) of hard foamed plastic, as well as an outer protective cover (4), and a conduit (5) drawn mainly axial- ly through the insulation layer (3) in the vicinity of the flow pipe (2) for a cable (6), whereby the protective cover (4) and the insulation layer (3) at the socketed end (1) terminate exactly on the end level of the flow pipe (2) and at the non-socketed end (7) as a uniform radial surface mainly at a distance corresponding to the length of the socket joint from the end of the flow pipe, c h a r a c ¬ t e r i z e d in that the insulation layer (3) of the socketed end (1) has a circular groove (8) surrounding the flow pipe (2), the width and depth of the groove correspon¬ ding at least to the cross-section of the cable conduit (5).

2. A socket pipe element according to Claim 1, c h a ¬ r a c t e r i z e d in that the socket pipe element is a straight pipe having one socketed end (1).

3. A socket pipe element according to Claim 1, c h a - r a c t e r i z e d in that the socket pipe element is a T-piece having all ends (1) socketed.

4. A socket pipe element according to Claim 1, c h a ¬ r a c t e r i z e d in that the socket pipe element is a pipe bend having one end (1) socketed.

5. A socket pipe element according to Claim 1, c h a ¬ r a c t e r i z e d in that the socket pipe element is a pipe bend having both ends (1) socketed.

6. A socket pipe element according to Claim 1, c h a ¬ r a c t e r i z e d in that the socket pipe element is a branch piece having two socketed ends (1) and one non- socketed end (7).