METHOD AND APPARATUS RELATING TO PIPE RENOVATION

Abstract: A mat (1) supporting a renovation tube (2) for the repair of a passage for the purpose of drawing it into the passage is provided with downwardly projecting longitudinal ridges (24, 25) which form, together with the underside of the mat (1) and the adjacent wall (26) of the passage, a chamber (27, 30) which can be pressurised with air to support some of the weight of the tube (2) whilst it is drawn into the passage.

Description: METHOD AND APPARATUS RELATING TO PIPE RENOVATION The present invention invention relates to the renovation of pipes especially underground pipes and particularly sewers. It is known from UK patent No.1501614 to use a carrier to transport a light impervious tube into a cleaned gas main for the purpose of adhering it to the walls under internal pressure to seal leaks. The problems of renovating sewers demand a much more robust solution and it has been proposed in UK Patent Application No. 8712954, later International Application no. 88/00435 to use a carrier with rollers or skids to carry a renovation tube of relatively large thickness and weight, compared with that of patent No 1501614, into a sewer, there to be inflated against the walls of the sewer and the carrier and cured to form a rigid substitute passage. The unit weight of the tube is estimated at nearly 35 pounds per metre for a tube suitable for lining a two foot diameter sewer. The total weight for a two hundred metre length would be in excess of 3 tons. Such loads demand that the friction loads which arise whilst the carrier is being drawn into the sewer be reduced as much as possible. According to the present invention a method of positioning a renovation tube in a passage consists of resting it on a carrier in the form of an elongated mat having at least two spaced downwardly projecting ribs extending continuously along its length to make sliding contact .with the floor of the passage, pressurising the chamber formed between the mat, the ribs and the floor of the passage sufficiently to support a proportion of the weight of the renovation tube carried on the mat, and drawing the mat whilst continuing to pressurise said chamber until all of the required length of mat and renovation tube has been drawn into and positioned, in said passage. Preferably the spaced downwardly extending ribs consist of two primary ribs defining a main pressurising chamber together with at least one secondary pair of such ribs placed outwardly of the primary ribs and defining subsidiary pressurised chambers. According also to the present invention apparatus for positioning a renovation tube in a passage consists of a carrier comprising a mat having at least two spaced downwardly projecting ribs extending continuously along its length and adapted to make sliding contact with the floor of the passage, air supply means including at least one nozzle to deliver air under pressure to the or each chamber defined by said mat, ribs and passage, draught means for gripping . the end of the mat and drawing it into said passage, and sealing means for preventing the leakage of air from the ends of the or each chamber. Preferably the mat may have two spaced ribs defining the edges of a single main chamber or it may have three spaced ribs defining the edges of two main chambers. As a further preference further ribs may be provided, all extending continuously longitudinally as before and each adapted to define an edge of a secondary chamber. The or each of the main chambers is or can be fed by a nozzle of the air supply means and nozzles may be provided for one or more of the secondary chambers. As a further preference the air supply means and draught means are positioned at the sme end of the mat. The invention will now be described by reference to the accompanying drawings of which; Figure 1 is a towing trolley for drawing a mat and renovation tube into a passage, Figure 2a is a cross section of figure 1 on plane I-I, Figure 2b is an enlargement of part of Figure 2a, and Figures 3 & 4 are cross sections of other exemplary form of mat. A mat 1 is to be used for the purpose of transporting a renovation tube 2 into a 200 metre long underground passage such as a sewer so that the tube 2 may be accessible from entry and exit pits at each end of the passage. As a preliminary it is necessary to pass a tow rope through the passage so that apparatus and materials can be pulled from end to end. Having done this a trolley 5, shown in fig.l is positioned at the entry pit. The trolley consists of a frame 6, a pair of plates 7 forming an aperture 8 for receiving the leading edge of the mat 1, a clamp plate 9 having an array of pins 10 positioned to pass through corresponding holes 11 in both plates 1 , a mechanism consisting of a bell crank 12 pivoted on a fulcrum beam 13, at one end and to the clamp plate 9 and at the other end to an operating rod 14 having a handle 15. The trolley 5 is also equipped with a tow ring 17, a pair of wheels 18, a nozzle 19 which is fed by a rigid pipe 20 itself connectible to a flexible air hose through connector 21, and a smooth upper surface 22 equipped with pegs or guides 23. The mat 1 is tough enough, by being reinforced or otherwise to sustain high tensile loads. It also has two primary ribs o r ridges 24 extending downwardly. On each outward side is a secondary rib 25. All the ridges 24/25 extend continuously along the mat 1. Fig.2a shows a primary chamber .27 defined by the wall 26 of the passage, the mat 1 and the two primary ridges 24. The nozzle 19 is shaped to conform in cross section closely to the cross-sectional shape of chamber 27. A secondary chamber 30 whose shape is defined by the wall 26, the. mat 1, one primary rib 24, and one secondary rib 25 is disposed one on each side of the primary chamber 27. As shown in fig 2b a seal 31 shaped to the contour of the passage wall 26, carried by the trolley 5 and pressed against the end of the mat 1 stops leakage of air from the ends of chambers 30. The mat 1, on entering the passage passes over a similar seal which is stationary and is placed in the passage at the entry pit. In operation the mat 1 is predrilled to receive the array of pins 11 and is fitted into the aperture 8. The clamp plate 9 is lowered by the operation of rod 14 and the pins 10 pass through the upper plate 7, mat 1, and the lower plate 7 to secure the mat 1 to the trolley for towing. The leading part of the renovation tube 2 is draped over the smooth upper surface 22 between the guides 23 which prevent it from falling off sideways and may be lightly clamped in position. The remainder of the renovation tube 2 is laid on the mat 1. The tow line from the exit pit is then attached to the tow ring 17 and an air hose, which also extends through the passage to the exit pit, is connected to the connector 21 and the trolley is placed in the passage. The towing operation is then started. Initially the towing load will be low but as more and more mat 1 and tube 2 go into the passage it will increase. Earlier or later the supply of air under pressure through the air hose , connector 21, pipe 20 and nozzle 19 to chamber 27 will be turned on. The pressure in the primary chamber 27, which is constantly elongating is to be kept, despite leakages, at a level which will support a large proportion of the combined weight of the mat 1 and renovation tube 2. Such pressurised air as may leak between the wall 26 and the primary ridges 24/25 passes into secondary chambers 30 there to exert upward pressure on the mat 1 so reducing the proportion of the load borne by the ridges 24/25 acting directly against the wall 26. During the later stages of the towing operation the primary and secondary chambers become very long e.g. 150 metres, and it may then be of advantage to pulse the supply of air and ' send waves of pressure along the chambers to obtain periodic unloading of the ridges and an easing of the tensile loads applied to the mat 1. Figure 3 shows an arrangement of ridges where two main chambers 33 and 34 are formed one on each side of a central ridge 35 and each bounded by a side ridge 36. Secondary chambers 37 and 38 would thus be formed laterally outwardly of ridges 36 and be closed by outer ridges 39, In such an arrangement there would be two nozzles on the trolley 5 shaped corresponding to the cross-sectional shape of chambers 33 and 34. The invention also envisages that the secondary chambers might themslves be pressurised by matching nozzles suitably arranged on the trolley 5. It is also envisaged that large passages or sewers might require more than four chambers to sustain the loads. In all the versions described the longitudinally extending ridges should be capable of deformation to allow the mat to conform as much as possible to the shape of wall 26 which need not necessarily be circular. The angled ridges 40 shown in fig.4 facilitate such deformation. After the mat has been pulled into position the pins 11 are withdrawn and the trolley separated from the mat and withdrawn from the exit pit. Thereafter various other operations are performed leading to the inflation of the renovation tube 2 hard against the passage wall 26 all the way around, and the curing of the tube 2 in that position.

Claims: Claims 1. A method of positioning a renovation tube in a passage is chacterised by resting it on a carrier in the form of an elongated mat having at least two spaced downwardly projecting ribs which extend continuously along its length to make sliding contact with the floor of the passage suffiently to support a proportion of the weight of the renovation tube carried on the mat, and drawing the mat whilst continuing to pressurise said chamber until all of the required length of the mat and renovation tube has been drawn into and positioned in said passage. 2. Apparatus for positioning a renovation tube in a passage comprises a mat characterised by having at least two spaced downwardly projecting ridges extending continuously along its length and adapted to make sliding contact with the floor of the passage, air supply means including at least one nozzle to deliver air under pressure to the or each chamber defined by said mat, ridges, and passage, and draught means for gripping the end of the mat and drawing it into said passage. 3. Apparatus according to claim 2 characterised by the provision of sealing means for preventing the leakage of air from the ends of the or each chamber. 4. Apparatus according to claim 2 characterised in that the mat has two spaced ridges defining the edges of a single main chamber. 5. Apparatus according to claim 2 characterised in that the mat has three spaced ridges defining the edges of two main chambers. 6. Appatatus according to claim 2 characterised in that the mat may be provided with further ridges and each adapted to define the edge of a secondary chamber. 7. Apparatus according to claim 2 characterised in that the or each of the main chambers and the secondary chambers can be fed by a nozzle of the air supply. 8. Apparatus according to claim 2 characterised in that the air supply means and the draught means are positioned at the same end of the mat. 9. Apparatus according to claim 2 characterised in that the mat is provided with ridges which are capable of deformation to allow the mat to conform as much as possible to the shape of the wall of the passage. 10. Apparatus according to claim 9 characterised in that the ridges which are angled as shown in figure 4.

Inventors: HUTTON FRANK ARTHUR, HUTTON, FRANK, ARTHUR
Applicants: HUTTON FRANK ARTHUR, HUTTON, FRANK, ARTHUR
Application year: 1989
Main classification: F16L55
IPC codes: F16L55