Patent ID: 12251887

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

FIG.1shows the steps201to205of method200of forming a pipe liner according to the present invention, and the cross section/orientation of the sheet of fabric1in each of said method steps as it is being formed into a pipe liner100. In step201, a sheet of fabric1is provided in the orientation A, suitably from a roll. The sheet of fabric1comprises a felt main body110exposed on side101which is to be the outer surface of the pipe liner, and a barrier coating120on the other side102which is to be the inner surface of the pipe liner. The sheet of fabric1has two opposing side edges103and104.

In step202, the sheet of fabric100has been folded over so that opposing side edges103and104have been brought together to meet at105, to form fabric sleeve10which has adopted the flattened orientation B.

In step203, the opposing side edges103and104have been moved apart to allow a strip of carrier material130comprising liquid sealant140to be inserted into the fabric sleeve10underneath opposing side edges103and104as shown in orientation C, so that the liquid sealant faces towards the two opposing side edges103and104of the sheet of fabric.

In step204, the opposing side edges103and104have been brought back together and joined with each other, with the strip of carrier material130and with the liquid sealant140to form the longitudinal seam106, as shown in orientation D, using suitable guides and pressurising equipment. The strip of carrier material130and the sealant140cover each of the two opposing side edges of the sheet of fabric, and any gap in-between the opposing side edges, to provide the pipe liner100having a barrier-coated inner surface102.

In step205, the pipe liner100has been expanded by applying a coolant liquid to the inner surface of the fabric sleeve10, in order to quench any liquid sealant140exposed on the inner surface of the pipe liner100and to test the integrity of the barrier coating120and the longitudinal seam106.

This method will now be described in more detail in reference to the apparatus300ofFIG.2. Apparatus300is a production line configured to manufacture pipe liners having a barrier-coated inner surface and an exposed fabric outer surface, for impregnating with curable resin and then for use in repairing damaged pipes as discussed herein. Apparatus300comprises a folding station310, a strip of carrier material application station320, a joining station330, a quenching station340and a stacking station350. The folding station310is fed with a sheet of fabric1, for example a sheet of polyester felt having a thickness of 5 mm and comprising barrier coating provided by a thin layer of polyurethane, from a roll311. The support table/conveyor on which the sheet of fabric1is arranged is omitted for clarity. The sheet of fabric1is arranged on the conveyor with the barrier coating side up and the exposed fabric side down. The folding station comprises side walls and edge guides which fold over the opposing side edges103and104of the sheet of fabric100in the direction shown by arrows312so that they meet and form a flattened tube shape of fabric sleeve10. Tension in the sheet of fabric provided by driver rollers further downstream on the apparatus (not shown) assists in retaining the flattened tube orientation of the fabric sleeve10.

The fabric sleeve10is then passed to the strip of carrier material application station320in this orientation. The strip of carrier material application station320comprises strip of carrier material roll321, strip of carrier material chute322, extruder323and edge guides324. The edge guides324contact the opposing side edges103and104of the fabric sleeve10in order to spread them apart sufficiently for the end of the strip of carrier material chute322to be arranged inside the fabric sleeve10through a gap between said two opposing side edges103and104. The strip of carrier material roll321dispenses a strip of carrier material130, for example a strip of polyurethane, into the strip of carrier material chute322which directs said strip of carrier material130into the fabric sleeve10in a position underneath the two opposing side edges103and104. As the strip of carrier material130moves down the strip of carrier material chute322, the extruder323extrudes liquid sealant140, for example molten polyurethane, onto the upper facing surface of the strip of carrier material130so that the liquid sealant140is arranged between the two opposing side edges103and104of the fabric sleeve100and the strip of carrier material130. This arrangement and functionality of the strip of carrier material application station320is shown in more detail inFIG.3. Here the side walls313of the production line are shown holding in and directing the fabric sleeve10through the strip of carrier material application station320and these side walls313are provided with edge guides324which can be seen holding open the fabric sleeve10as it progresses through the strip of carrier material application station320. This opening of the fabric sleeve10allows the strip of carrier material chute322to direct the strip of carrier material130into the fabric sleeve100. As the strip of carrier material130progresses down the strip of carrier material chute322, the extruder323, supplied by liquid sealant supply line325, deposits the liquid sealant140onto the strip130as it enters the fabric sleeve10. Weight326is arranged downstream of the strip of carrier material chute322and functions to close the opening of the fabric sleeve10after insertion of the strip of carrier material130and the liquid sealant140. Weight326may be omitted and the function of closing the fabric sleeve10may be performed by the chiller rollers331.

The fabric sleeve10is then passed to the joining station330. The joining station330comprises chiller rollers331which apply pressure to and simultaneously cool the fabric sleeve100comprising the strip of carrier material130and the liquid sealant140in order bond together the two opposing side edges103and104of the fabric sleeve100to the strip of carrier material130and the sealant140, to form said longitudinal seam106and so to form a continuous barrier on the inner surface of the pipe liner100.

The pipe liner100is then passed to the quenching station340. The quenching station340comprises entry point roller341, low point roller342and exit point roller343. As shown inFIG.2, these rollers direct the pipe liner100into a v-shape as it passes through the quenching station. At the low point of the v-shape, the pipe liner100comprises an aqueous solution400of a suitable dye, for example a red dye, but this could be any colour of dye which would contrast well with the white/off-white colour of the fabric of the pipe liner. The aqueous solution400is present in an amount which completely fills a short section of the pipe liner100. This aqueous solution of dye400was introduced into the pipe liner100when the leading end of the pipe liner100reached the exit point of the quenching station340. The aqueous solution of dye400contacts the entire inner surface of the pipe liner100progressively as it passes through the quenching station340, remaining at the low point of the quenching station340due to gravity. When the aqueous solution of dye400contacts the inner surface of the pipe liner100, it solidifies (through cooling) any liquid sealant which is exposed on the inner surface of the pipe liner100and which has not been solidified by the chiller rollers331in the joining station330. Also, the aqueous solution of dye400tests the barrier coating for leaks, as any dye which is visible on the exposed outer fabric of the pipe liner100must have leaked through a gap or fault in the pipe liner100. This provides a clear indication of the manufacturing quality of the pipe liner for the operator, which helps to provide an efficient and effective manufacturing process. The quenching station also comprises a vessel344for catching any of the aqueous solution of dye400which leaks out of the pipe liner100and also for catching the aqueous solution of dye400which drains out of a trailing end of the pipe liner100when it passes through the quench station after completion of the manufacture of the pipe liner100.

The pipe liner100is then passed to the stacking station350which comprises ramp351and pallet352. The pipe liner100is directed up the ramp351, allowing any of the aqueous solution of dye400inside the pipe liner100to drain to the low point of the quenching station340. From the top of the ramp, the pipe liner100is directed to the pallet352for stacking in a flattened state. The pipe liner100is then ready for transportation to a customer, suitably free of leaks and cross-welded regions which would affect the function of the pipe liner100.

In summary, the present invention provides a method of manufacturing a pipe liner for lining the inside of a pipe, for example a water or sewerage pipe requiring repair. The pipe liner is mainly formed of a fabric sleeve, or a plurality of fabric sleeves, and comprises a fluid-proof barrier coating on the inside surface of the pipe liner. The method involves arranging a strip of carrier material comprising a liquid sealant inside the fabric sleeve of the pipe liner and in registration with two opposing side edges of the sheet of fabric, facing an inner barrier coating of the fabric sleeve. The method can advantageously provide such a pipe liner with an inner barrier coating without everting the pipe liner after manufacture. The present invention may also provide a way of avoiding internal cross-welding of said pipe liners and a method for testing the integrity of the barrier coating of said pipe liners. The present invention also provides an apparatus for carrying out these methods.

Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of other components. The term “consisting essentially of” or “consists essentially of” means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect of the invention.

Typically, when referring to compositions, a composition consisting essentially of a set of components will comprise less than 5% by weight, typically less than 3% by weight, more typically less than 1% by weight of non-specified components.

The term “consisting of” or “consists of” means including the components specified but excluding addition of other components.

Whenever appropriate, depending upon the context, the use of the term “comprises” or “comprising” may also be taken to encompass or include the meaning “consists essentially of” or “consisting essentially of”, and may also be taken to include the meaning “consists of” or “consisting of”.

The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention as set out herein are also to be read as applicable to any other aspect or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each exemplary embodiment of the invention as interchangeable and combinable between different exemplary embodiments.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.