Pipeline with concentric pipes

Abstract

 A pipeline intended for laying in the ground comprises a perforated outer pipe (25) and a perforated inner pipe (27) located inside the outer pipe (25), which inner pipe (27) is provided with a filter material (12) on the outside. The inner pipe (27) is ribbed with annular depressions and ridges (10) and the filter material (12) comprises a mat (12) wound around the inner pipe (27). The outer pipe (25) is made up of a number of pipe sections (7,8) which are joined to one another by means of a sleeve connector (20,22).

Description

[0001] The invention relates to the field of pipelines, such as drainage pipelines, which are intended to be laid in the ground. Pipelines of this type are widely used for draining areas in relation to control of the groundwater level. They are also used for the clean-up of polluted soil and the isolation of dumps and industrial sites. Yet further applications relate to degassing, aeration and injection of sites.

[0002] Various techniques are employed for laying these pipelines. According to a first possibility, a trench is excavated in the soil, the pipeline subsequently being laid in said trench. Finally, the trench is filled.

[0003] Another possibility is to bore a horizontal hole, into which the pipeline is subsequently pulled. The advantage of this technique is that the surface of the ground concerned is not affected. Consequently it is possible also to lay pipelines in soils which are not accessible from above, such as, for example, is the case with built-up areas or dumps.

[0004] Since with the latter technique the pipeline has to be pulled through the hole, the surface of said pipeline must be fairly smooth. Moreover, any couplings must virtually not protrude, since otherwise the pipeline could become stuck. This restriction with regard to the surface of the pipeline therefore has the disadvantage that certain pipelines cannot be processed. This is in particular the case with drainage pipelines which have a mat of filter material wound around the outside.

[0005] The aim of the invention is, therefore, to provide a pipeline which does not have this disadvantage. Said aim is achieved by means of a pipeline, intended to be laid in the ground, comprising a perforated outer pipe and a perforated inner pipe which is located inside the outer pipe and is provided with a filter material on the outside.

[0006] According to the invention, the following procedure can be employed when laying the pipeline according to the invention in the ground: boring a hole in the ground, placing the outer pipe in the hole and placing the inner pipe in the outer pipe. Since the outer pipe can be smooth, the latter can be pulled into the hole without problems. The outer pipe installed in this way then provides an excellent guide for fitting the inner pipe, even if the latter is wound round with filter material.

[0007] Preferably, the inner pipe is ribbed with annular depressions and ridges and the filter material comprises a mat wound around the inner pipe.

[0008] The inner pipe can be made up of a number of pipe sections, which are joined to one another by means of internal expansion connectors. Preferably, the expansion elements are ribbed correspondingly to the inner pipe sections. Said expansion elements can consist of a sleeve provided with a longitudinal cut, such that in the state of rest the outer diameter of the sleeve is greater than the inner diameter of the pipe sections.

[0009] The outer pipe can also be made up of a number of pipe sections which are joined to one another by means of a sleeve connector. Said sleeve connector can have two concentric sleeve sections which can be placed inside one another and which interact with one another by means of barb-shaped teeth.

[0010] The invention also relates to an outer and inner pipe for use in the pipeline according to the invention.

[0011] The invention will now be explained in more detail with reference to the figures.

[0012] Figure 1 shows a side view, partially in cross-section, of an expansion element according to the invention.

[0013] Figure 2 shows a compressed expansion element and two pipe ends.

[0014] Figure 3 shows a pipeline, wound round with filter material, made up by means of expansion elements according to Figures 1 and 2.

[0015] Figures 4 and 5 show a tool for compressing the expansion element.

[0016] Figure 6 shows a cross-section along VII-VII in Figure 3.

[0017] Figure 7 shows part of an outer pipe with sleeve connector.

[0018] Figure 8 shows a longitudinal section of a made-up inner and outer pipe according to the invention.

[0019] The expansion element 1 shown in Figure 1 has a mid section 2 with a smooth surface and two end sections 3, 4 provided with ribs on the outside. The expansion element is cylindrical, but has a longitudinal opening 5 of a certain width.

[0020] The jaws 6, indicated by broken lines, of tongs can engage on the smooth mid section 2 of the expansion element 1 (see Figures 4, 5) in order to pinch the expansion element 1 together.

[0021] In this position, the expansion element 1 can be slid into the open ends of the pipe sections 7, 8, which are shown in part.

[0022] This causes the pipe sections to come into contact with the smooth mid section 2, after which the jaws 6 are removed and the expansion element 1 is able to expand in such a way that its ribs 9 engage in the inner grooves formed by the ribs 10 of the pipe sections 7, 8. The width of the longitudinal opening 5 must then be minimal.

[0023] In any event, longitudinal opening 5 must be so small that the expansion connector cannot be compressed as a consequence of tensile forces on the joint in such a way that said expansion connector element becomes loose. The various features can be seen more clearly in the cross-section in Figure 3.

[0024] The pipe sections 7, 8 have filter openings 11, through which water is able to seep to the inside.

[0025] In order to prevent the filter openings 11 from becoming clogged, a layer of filter material 12, known per se, is wound around the finished pipe, consisting of the pipe sections 7, 8. The layer of filter material 12 is held in place by means of spirally wound wires 13.

[0026] Figure 4 shows the expansion element 1 in the expanded state, as well as tongs 14 with jaws 6 ready to engage on the expansion element 1.

[0027] In Figure 5 the expansion element has been pinched together by the tongs 14, one edge 15 of the longitudinal cut in the expansion element 1 being held anchored in the nose 17 on one of the jaws 6.

[0028] Figure 6 shows the cross-section through expansion element 1, pipe section 7 and filter layer 12. The outer pipe of the pipeline according to the invention is shown in Figure 7. Said pipe is made up of a number of pipe sections 18, 19, on the ends of which sleeve sections 20 with internal toothing 21 and sleeve sections 22 with external toothing 23 are fixed.

[0029] The pipe sections 18, 19 are provided with slits 24, through which groundwater is able to seep to the inside. Other openings, such as circular holes or other perforations, could also be made.

[0030] In view of the fact that the outer surface of the pipe as made up from the pipe sections 18, 19 is smooth and also in view of the smooth outer surface of the sleeve sections 20, 22, said pipe and sleeve sections can easily be slid into a pre-bored hole in the ground.

[0031] Figure 8 shows the situation where the pipe, which is indicated in its entirety by 25 and is made up of pipe sections 18, 19, is in the ground 26.

[0032] The inner pipe 27 is located inside the pipe 25, as is shown in Figure 3. In view of the smooth internal surface of the pipe 25, the pipe 27 can easily be inserted as the filter layer 12 on the outside of the inner pipe 27 slides over the internal surface of pipe 25 without too great a friction.

Claims

1. Pipeline, intended to be laid in the ground, comprising a perforated outer pipe (25) and a perforated inner pipe (27) which is located inside the outer pipe (25) and is provided with a filter material (12) on the outside.

2. Pipeline according to Claim 1, wherein the inner pipe (27) is ribbed with annular depressions and ridges (10) and the filter material comprises a mat (12) wound around the inner pipe.

3. Pipeline according to Claim 2, wherein the inner pipe (27) is made up of a number of pipe sections (7, 8), which are joined to one another by means of internal expansion elements (1).

4. Pipeline according to Claim 3, wherein the expansion elements (1) are ribbed correspondingly to the inner pipe sections (7, 8).

5. Pipeline according to Claim 4, wherein the expansion elements consist of a sleeve (1) provided with a longitudinal cut (5), such that in the state of rest the outer diameter of the sleeve (1) is greater than the inner diameter of the pipe sections (7, 8).

6. Pipeline according to one of the preceding claims, wherein the outer pipe (25) is made up of a number of pipe sections (18, 19) which are joined to one another by means of a sleeve connector (20, 22).

7. Pipeline according to Claim 6, wherein the sleeve connector has two concentric sleeve elements (20, 22) which can be placed inside one another and which interact with one another by means of barb-shaped teeth (21, 23).

8. Pipeline according to one of the preceding claims, wherein the outer pipe (25) has a smooth outer surface.

9. Method for laying a pipeline according to one of the preceding claims in the ground, comprising boring a hole, placing the outer pipe (25) in the hole and placing the inner pipe (27) in the outer pipe (25).

10. Perforated pipe (25) for use in a pipeline according to one of Claims 1-8, made up of a number of pipe sections (18, 19) which are joined to one another by means of a sleeve connector (20, 22).

11. Perforated pipe (27), provided with annular depressions and ridges (10), for use in a pipeline according to one of Claims 1-8, made up of a number of pipe sections (7, 8) which are joined to one another by internal expansion elements (1).

Drawing