Lining material for pipes and method for lining pipes

Abstract: The present invention provides:- a lining material comprising a flexible fabric tube which is a circularly knitted fabric comprising a ground and a plurality of tufts of fabric projecting from the ground on the inside thereof, and a flexible sleeve within the tube, the flexible sleeve being substiantially impervious to at least one of a gas and a liquid and being capable of being inflated in use to generally radially outwardly bear on the tube to force the tube in use into general conformity with a tubular passageway.

Description: FIELD OF THE INVENTION This invention relates to lining of passages and materials for use in so doing. BACKGROUND TO THE INVENTION Pipe which is buried in the ground is likely to deteriorate both from the inside and outside when fluids such as aqueous materials are carried on the inside and water and/or solutions can flow over the outside. Above ground pipes can also deteriorate due to external factors and internal factors. A typical example of the above is sewer piping and in this case there is the additional hazard of ground movement which may crack or even crush the pipe. Other examples include petroleum pipelines and pneumatic transport conduits. Within Australia and in other countries, there are many kilometres of sewer pipe which has be laid in the ground in excess of 20 years and which is presently showing considerable deterioration. Of course, it is always possible to dig up roads and soil and replace the pipe completely but to do so is quite expensive. One known way of overcoming these disadvantages is disclosed in GB-A-2181670 where there is a knitted flexible tube having a resin applied to its exterior. The bonding between resin and knitted flexible tube is by interstices between elongate close knitted loop weft and warp threads. While some improvement is obtained by providing such a liner material the attachment between resin and fabric is tenuous and can lead to destruction of the liner material. In this specification references to tube or tubes is to be taken as reference to flexible fabric tube(s) linear material. The present invention seeks to provide a lining material and a method for lining pipes in situ. This goal is reached by the lining material according to claim 1 and the method according to claim 9 and the use in passage ways according to claims 12 and 13. While the present invention has a particular application to sewer pipes, there are many other pipes to which the present invention can be applied. However, the lining material of the present invention is not restricted to lining pipes in situ and may be applied to lining passages of natural or man-made origin such as cavities or bores in pre-existing substrate. Examples of such passages include holes drilled through soil or rock such as under roads and naturally occurring wells or sinks. Other examples of such passages include core holes, well drilling, and in use in lining of conduits of natural or man-made origin. SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided a lining material comprising: a flexible fabric tube which is a circularly knitted fabric characterised in that: the fabric has a ground and a plurality of tufts of fabric projecting from the ground on the inside thereof, and a flexible sleeve within the flexible fabric tube, a settable resin or cementatious material impregnated into the flexible tube and tufts between the flexible fabric tube and the flexible sleeve; the flexible sleeve being substantially impervious to at least one of a gas and a liquid and being capable of being inflated in use to generally radially outwardly bear on the flexible fabric tube and resin to force the tube in use into general conformity with a tubular passageway. According to another aspect of the present there is provided a method of lining a tubular passageway comprising: using a flexible fabric tube which is a circularly knitted fabric, characterised in arranging the flexible fabric tube which has a ground and a plurality of tufts of fabric so that the tufts extend inwardly projecting from the ground on the inside thereof, locating a flexible sleeve within the flexible fabric tube, the flexible sleeve being substantially impervious to at least a gas or a liquid, impregnating at least a substantial proportion of the flexible fabric tube and at least a substantial proportion of the tufts with a settable resin or a settable cementatious material, locating the flexible fabric tube and the sleeve within said passageway to be lined, inflating the sleeve with a gas or a liquid to cause the flexible fabric tube to closely conform to the interior of the passageway to be lined; and allowing the resin or cementatious material to set whereby to form a liner for the passageway. PREFERRED ASPECTS OF THE INVENTION The use of a resin is preferred over the use of a cementatious material. The invention is preferably applied to the lining of pipes. The sleeve can be located within the tube either before or after the impregnation of the tube with the resin although the former is preferred. The sleeve may be located within the tube before or after the location of the tube within the pipe. The sleeve is preferably formed of a vinyl or elastic material. The tube is preferably of a length to extend between adjacent manhole covers associated with the pipe. That length will commonly be up to 100 meters or more. The length of the sleeve should be appropriate to the length of the tube but some additional length may be desirable to facilitate sealing one end of the sleeve and utilising the other end for inflation purposes. In addition to the sleeve previously mentioned, hereinafter called "the first sleeve" there may be a second sleeve located on the outside of the tube. The second sleeve may be itself independent of the tube but may be a coating on the outside of the tube. The first sleeve might also be a coating applied to the inside of the tube but this is not preferred. That second sleeve and the first sleeve are preferably located with respect to the tube before the impregnation with the resin or cementations material as the first sleeve and the second sleeve can facilitate the application of resin or cementatious material. In this last respect, resin or cementatious material may be introduced at one end between the first sleeve and the second sleeve and then pushed towards the other end by a roller or preferably two rollers which nip the lining material. It is to be noted that it is desirable that the second seleeve be transparent or at least translucent as this will enable a sighting of the extent to which the resin or cementatious material has wet the tube. If there is insufficient wetting, manipulation may be done to spread the resin or cementatious material. The method of the present invention may be utilised to repair short lengths of pipe or relatively long lengths of pipe. The resin may be any suitable material but some suitable materials include polyurethanes and epoxy resins. The resin is preferably a cold setting or thermo-setting resin and may be aided in setting by the use of an appropriate catalyst or cross-linking material. A setting accelerator is preferably used so as to reduce setting time to a commercially acceptable time. The tube may be pre-impregnated with a component of a settable resin mixture to which another component may be added at time of use. The present invention also provides a lining material comprising the above tube with the above sleeve located therewithin. In a preferred aspect, the tube is located between a first sleeve and a second sleeve. The present invention also provides an orifice, particularly a pipe, lined with the above tube. A suitable material for the tube is that shown in Australian Patent Specification No. 528797. The pore sizes shown therein are particularly suitable for retention of resin and promotes the even distribution of the resin into the tufts by capillary action. In some instances it may be desirable that the tube is made of a High Tensile material such as Kevlar or high temperature fibre such as Nomex. The diameter of the tube and sleeve should be appropriate to suit the orifice, such as a pipe, which is to be lined. The tufts of the tube are preferably located on the inside. In one instance, two or more such tubes were used; one inside the other and, in the case of two tubes, preferably with the tufts of the tubes adjacent one another. The tuft length will generally be 3 mm or greater. Tuft lengths of 10 mm or more are particularly desirable. The ground thickness will generally be 0.25 mm or greater. A ground thickness of 3 mm or greater is particularly preferred. Specific embodiments in accordance with this invention will now be described by way of non-limiting examples. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS Example 1 A length of tubing was taken of about 100 meters length and about 200 mm in diameter. The tubing was a circularly knitted tube comprising a ground and having an internal pile surface. More particularly, the internal pile surface was of terry towel tufts and was of the general type of material shown in Australian Patent Specification No. 528797. Within the tube was a vinyl liner sleeve of about the same internal diameter as the tube and of a length about 1.5 meters longer than the length of the tube such that the sleeve projected from both ends of the tube. The resulting composite product was then passed through a bath containing a thermo-setting resin with catalyst and accelerator and thereafter the resin impregnated product was passed between nip rolls so as to force the resin through the tube and thoroughly wet it. The wetted composite was then folded along its length approximately into the shape of a U to reduce the apparent cross-sectional size and it was passed into a pipe to be lined. The manner of passing it into the pipe to be lined is not material but one method includes attaching a rope to one end and drawing it through the pipe. When the wetted composite was properly located within the pipe one end of the sleeve was closed, such as with a clamp, and thereafter air, steam or water was passed under low pressure into the other end of the sleeve so as to expand the sleeve and cause the wetted composite to take up an approximately cylindrical form and to press the tube into intimate contact with the pipe. Air, steam or water pressure was maintained for about an hour or until the resin had set. The sleeve was thereafter deflated and removed. This removal is not essential. Thereafter the ends of the tube were trimmed as desired. Example II Example 1 was repeated excepting that within the tube was a first sleeve and on the outside of the tube was a second sleeve. In this instance, the resin was introduced between the first sleeve and the second sleeve and was moved along the length of the tube between the sleeves by means of nip rolls. The above methods and products have been found to produce an excellent lining to an orifice, such as a pipe, which will give many years of service. In particular, the tube is strong and seamless having no sewn joints and is easily wet out. Further, the tube has some stretch in it both longitudinally and circumferentially. The circumferential stretch is of particular value in coming into conformity of shape. For very large orifices or very large pipes, it may be necessary to take two or more such tubes, slit them longitudinally, and sew them together longitudinally to obtain the required diameter.

Claims: A lining material comprising: a flexible fabric tube which is a circularly knitted fabric characterised in that : the fabric has a ground and a plurality of tufts of fabric projecting from the ground on the inside thereof, and a flexible sleeve within the flexible fabric tube, a settable resin or settable cementatious material impregnated into the flexible tube and tufts between the flexible fabric tube and the flexible sleeve; the flexible sleeve being substantially impervious to at least one of a gas and a liquid and being capable of being inflated in use to generally radially outwardly bear on the flexible fabric tube and resin to force the tube in use into general conformity with a tubular passageway. A lining material as claimed in claim 1, wherein the flexible fabric tube comprises a yarn which is knit into stitches defining said ground and stitches defining said tufts which are loop pile tufts extending from the ground. A lining material as claimed in claim 2, wherein the tufts extend from the ground to a height of not less than 3 mm. A lining material as claimed in any preceding claim, wherein the ground has a thickness of not less than 0.25 mm. A lining material as claimed in any preceding claim, wherein, in addition to said flexible sleeve, hereinafter called "the first sleeve", there is a second flexible sleeve located over the outside of the flexible fabric tube. A lining material as claimed in claim 5, wherein the second flexible sleeve is transparent or translucent to an extent that in use wetting of the flexible fabric tube by the settable resin or cementatious material can be observed. A lining material as claimed in any preceding claim, wherein the flexible fabric tube comprises a High Tensile strength yarn. A lining material as claimed in any preceding claim, wherein the flexible fabric tube is pre-impregnated with a component of a settable resin mixture to which another component of said settable resin mixture can be added at time of use. A method of lining a tubular passageway comprising: using a flexible fabric tube which is a circularly knitted fabric, characterised in arranging the flexible fabric tube which has a ground and a plurality of tufts of fabric so that the tufts extend inwardly projecting from the ground on the inside thereof, locating a flexible sleeve within the flexible fabric tube, the flexible sleeve being substantially impervious to at least a gas or a liquid, impregnating at least a substantial proportion of the flexible fabric tube and at least a substantial proportion of the tufts with a settable resin or a settable cementatious material, locating the flexible fabric tube and the sleeve within said passageway to be lined, inflating the sleeve with a gas or a liquid to cause the flexible fabric tube to closely conform to the interior of the passageway to be lined; and allowing the resin or cementatious material to set whereby to form a liner for the passageway. A method as claimed in claim 9 wherein the flexible fabric tube and the flexible sleeve comprise a lining material as claimed in any of claims 1 to 8. A method as claimed in claim 9, wherein a second flexible sleeve is located over the outside of the flexible fabric tube, the second flexible sleeve being transparent or translucent to an extent that in use wetting of the tube by a settable resin can be observed. A passageway having a lining comprising a lining material as claimed in any of claims 1 to 8. A passageway having a lining effected by a method as claimed in any one of claims 9 to 11. A passageway as claimed in claim 12 or 13 in which the passageway which receives a lining material of claims 1 to 8 in accordance with the method of claims 9 to 11, comprises an underground pipe or conduit.

Inventors: CANT RICHARD SAMUEL, CANT, RICHARD SAMUEL
Applicants: CANT RICHARD SAMUEL, CANT, RICHARD SAMUEL
Application year: 1995
Main classification: F16L55
IPC codes: F16L55