WO1990012242A1

WO1990012242A1 - Method and pipe element for the relining of sewers

Info

Publication number: WO1990012242A1
Application number: PCT/GB1990/000521
Authority: WO
Inventors: Nigel Rice
Original assignee: Nigel Rice
Priority date: 1989-04-06
Filing date: 1990-04-06
Publication date: 1990-10-18
Also published as: GB8907746D0

Abstract

A method of relining an existing sewer comprises the steps of (i) introducing a flexible tubular waterproof membrane into the sewer or the like, (ii) introducing a pipe element (1) into the tubular membrane so as to fit circumferentially round the internal wall of the sewer, the pipe element having first and second opposite ends (9, 11) slidingly located one within the other so that the peripheral length of the pipe element (1) can be varied, and (iii) hydraulically expanding the pipe element, for instance by injecting grout through hole (6), until it is restrained by the internal wall of the sewer. The pipe element (1) may comprise two or more segments (1, 2) with a number of sliding joints. In its compressed state the element can be carried through an already relined section of sewer so that operation can be carried out under the protection of the relined section.

Description

Method and pipe element for the relining of sewers. This invention relates to the renovation of existing sewers or like underground pipes.

It is known to renovate sewers by relining them. The functions of the liner are fourfold, namely, to provide structural support, to provide a watertight seal (to prevent the infiltration and ex-filtration of liquids and also the ingress of tree roots), to provide chemical and corrosion resistance and to afford a smooth hydraulic flow to the contents. In sewers of sufficient dimensions that a man may enter to undertake such renovation work known techniques of renovation are disadvantageous in that:- (i) In order to prepare or affix the new liner a man may be required to work in an unrenovated portion of the old sewer, ahead of the new liner, which portion may be structurally unstable and hence hazardous, (ii) If the liner is used as permanent formwork to support the injection of grout, then the liner usually has to be internally braced or supported during the grouting process.

(iii) Applied coatings such as Guniting, ferro- cement or sprayed polymeric materials have difficulty in accommodating the design loadings experienced in U- shaped, rectangular or square section sewers.

In my International patent application publication No.WO 89/04435 there is disclosed a method of providing the waterproofing function of the liner by the use of a tubular membrane drawn into the sewer and the structural function by means of short pipe elements inserted into this membrane. The resulting void between the pipe elements and the existing sewer is filled with grout.

In the present invention, a tubular membrane is, as before, employed to provide the waterproofing function. However the structural pipe element which provides the three remaining functions is initially smaller than the internal size of the sewer, but is expanded, for example, by pressure injecting grout into the pipe element. This method allows work to advance with the operator protected beneath the new structural liner consisting of the waterproof membrane and the pipe elements. The void between the liner and the sewer wall can be greatly reduced, or eliminated, and the liner can be designed for any shape.

According to one aspect of the present invention there is provided a method of relining an existing sewer or the like which method comprises the steps of (i) introducing a flexible tubular waterproof membrane into the sewer or the like,

(ii) introducing into the tubular membrane a pipe element configured to fit round the internal wall of the sewer and having first and second opposite ends slidingly located one within the other so that the length of the pipe element around its periphery can be varied, and

(iii) hydraulically expanding the pipe element until it is restrained by the internal wall of the sewer. Steps (i) to (iii) are repeated to give the desired length of relining.

According to another aspect of the present invention there is provided a pipe element for use in relining an existing sewer, having the form of an open- ended tube confijju ed to fit round the internal wall of the sewer, the first and second ends of the tube being slidably located one within the other. The pipe element may comprise two or more segments each in the form of an open-ended tube and having first and second opposite ends wherein the first end of each segment and the second end of the adjacent segment are located one within the other and at least one of the ends of each segment is slidable with respect to the end of the adjacent segment.

In a preferred embodiment the pipe element includes first and second segments wherein said first end of the pipe element is constituted by a first end of the first segment and said second end of the pipe element is constituted by a second end of the second segment. In this case, the second end of the first segment and the first end of the second segment are similarly slidingly located, or are fixedly located, one within the other.

If desired, the pipe element may include more than two segments in which case said first end of the pipe element is constituted by a first end of one of the segments and said second end of the pipe element is constituted by a second end of one of the second segments with the adjacent ends of all segments being either fixedly or slidingly located one within the other.

Preferably, each of the segments is in the form of an open-ended tube of, for example, substantially rectangular cross-section. In this case the expansion of the pipe element can be achieved by introducing, for example, grout into the tube.

In an embodiment of the invention the pipe segments may be reinforced by integral reinforcing ribs. In another embodiment of the invention pipe segments may be reinforced by reinforcing bars.

In a further embodiment of the invention, the join between adjacent segments may be rendered fluid tight by means of an 0-ring. In another embodiment of the invention segments may be constructed of a translucent material. For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which : Figure'1 is a view of one embodiment of a pipe element of the invention as applied to a circular sewer, and

Figure 2 is an exploded view of another embodiment of a pipe element of the invention as applied to a U- shaped sewer.

Referring now to Figure 1 the pipe element 13 comprises first and second extruded segments 1,2 in the form of open ended tubes and preferably formed of uPVC. Segment 1 has a first end 9 and a second end 10 and segment 2 has a first end 12 and a second end 11.

Segments 1 and 2 together form a pipe element in the form of a broken ring having a diameter less than the internal diameter of the sewer, a first end constituted by first end -9 of segment 1 and a second end constituted by second end 11 of segment 2. First segment 1 may be internally reinforced with ribs 8. έecond segment 2 is of such dimensions that it can form a telescopic joint with first segment 1, allowing the pipe element to be compressed or expanded. Second segment 2 forms an arc of a circle of such a length that it bridges the gap between the ends 9,10 of the first segment 1, when the pipe element 13 is expanded, and overlaps the ends 9,10 of the first segment 1. Second segment 2 includes a hole 6 through which grout is injected and a valve 7 through which air is bled. Steel reinforcing bars 3 may be formed into arcs and passed into the hollow spaces between the ribs 8 in first segment 1. The number and dimensions of these bars may be varied in accordance with the structural design requirements for any particular sewer or section of sewer. The bar is designed such that one end telescopes into the other. One end, in this case the second end 10, of first segment 1 is fixedly attached to one end 12 of second segment 2. The free end 9 of first segment 1 is fitted with a seal 4. This seal 4 may be a rubber 0-ring, or the like, fitted into a groove or bonded to free end 9. The free end 9 of first segment 1 is adapted to slide into the free end 11 of second segment 2 so that the pipe element 13 forms a complete ring. The peripheral length of the pipe element 13 is reduced by sliding the end 9 of first segment 1 further inside the end 11 of second segment 2. Thus the pipe element 13 may be entered into the sewer through any portion of the sewer that has already been lined. In the use of the pipe element the sewer to be renovated has a tubular membrane drawn into it. This membrane may ideally be kept inflated with high volume, low pressure air.

The first pipe element 13 is then entered into the membrane and positioned in place. Grout is injected through hole 6, air being bled through a suitable valve• 7 or the like. The uPVC of which the first and second segments are formed may be translucent in order that the grout fill may be observed. Once the air has been bled and valve 7 closed, continued application of grout under pressure will cause the first and second segments to slide with respect to one another so that the pipe element extends outwardly until it is restrained by the original sewer wall. Subsequent pipe elements are then carried through the lined portion of the sewer by virtue of their reduced diameter in the compressed state, thus ensuring that the operator is always working within a supported structure. Referring now to Figure 2, the U-shaped pipe element 20 here consists of segments 14, 15, 16 and 17. Segment 15 provides the sides and invert and segment 14 provides the top beam of the pipe element 20. Segments 14 and 15 may be reinforced with steel or other suitable materials. The free ends 18,19 are fitted with a seal. The segments 16,17 are formed into right angles and have free ends 21,22 of such dimensions that they form a telescopic joint with free ends 18,19 respectively of the segments 14,15. The peripheral length of the pipe element 20 thus formed may be reduced by sliding the free ends 18,19 of the segments 14,15 further into the segment 16,17 respectively. Thus the size of the pipe element 20 can be reduced in both width and height.

Either of the segments 16,17 may include a hole 6 and a valve 7 or the like. Thus the pipe element may be outwardly expanded in the same manner as the circular pipe element of Figure 1, by injecting grout under pressure.

Any other shape of sewer may be relined by the use of a pipe-element comprising a combination of appropriately shaped segments.

Sewers of insufficient dimensions for a man to enter may be renovated by means of the invention by the use of remote techniques to install the pipe elements and the grout.

Claims

1. A method of relining an existing sewer or the like which method comprises the steps of (i) introducing a flexible tubular waterproof membrane into the sewer or the like,

(ii) introducing into the tubular membrane a pipe element (1) configured to fit round the internal wall of the sewer and having first and second opposite ends (9,11) slidingly located one within the other so that the length of the pipe element (1) around its periphery can be varied, and

(iii) hydraulically expanding the pipe element (1) until it is restrained by the internal wall of the sewer.

2. A method of relining an existing sewer or the like according to claim 1, wherein the hydraulic expansion of the pipe element is achieved by injecting grout into the pipe element.

3. A pipe element (1) for use in relining an existing sewer, having the form of an open-ended tube configured to fit round the internal wall of the sewer, the first and second ends (9,11) of the tube being slidably located one within the other.

4. A pipe element according to claim 3 and comprising two or more segments (1,2) each in the form of an open-ended tube and having first and second opposite ends (9,10;12,11) wherein the first end (9,12) of each segment and the second end (10,11) of the adjacent segment are located one within the other and at least one of the ends (9,11) of each segment is slidable with respect to the end of the adjacent segmen .

5. A pipe element according to claim 4 and having first and second segments, wherein said first end of the pipe element is constituted by a first end ( ) of the first segment and said second end of the pipe element is constituted by a second end (11) of the second segment.

6. A pipe element according to claim 5, wherein the second end of the first segment and the first end of the second segment are similarly slidingly located, or are fixedly located, one within the other.

7. A pipe element according to claim 4, wherein the pipe element (20) includes more than two segments (14,15,16,17), said first end of the pipe element being constituted by a first end of one of the segments and said second end of the pipe element being constituted by a second end of one of the other segments with the adjacent ends of all segments each being either fixedly or slidingly located one within the other.

8. A pipe element according to any of claims 4 to 7, wherein each of the segments is in the form of an open-ended tube of substantially rectangular cross- section.

9. A pipe element according to any of claims 4 to 8, wherein the pipe segments are reinforced by integral reinforcing ribs (8) and/or reinforcing bars (3).

10. A pipe element according to any of claims 4 to 9, wherein the join between adjacent segments is rendered fluid tight by means of an O-ring (4).

11. A pipe element according to any of claims 4 to 10, wherein at least one of the segments is constructed of a translucent material.

12. A relined sewer comprising an internal wall, a tubular waterproof membrane within the wall, and a series of pipe elements according to any of claims 3 to 11 holding the tubular membrane in place against the wall.