IL43417A - Method and apparatus for lining a pipe - Google Patents

Abstract

1416947 Lining pipes TAKATA KOJYO CO Ltd 17 Oct 1973 [18 Oct 1972] 48283/73 Heading F2P A method of lining a pipe B (e.g. to repair the pipe) includes the steps of inserting in the pipe B a synthetic organic polymeric resin tube 8 having reinforcing fibres embedded therein and extending peripherally thereof and having an outside diameter less than the inside diameter of the pipe B, expanding the tube 8 while in a soft flexible condition at an elevated temperature into tight engagement 8<SP>1</SP> with the inside face of the pipe B by means of a pressurized fluid within the tube 8, and relieving the fluid pressure and cooling the tube while in engagement with the pipe. The tube 8 may be formed from a thermoplastic material, e.g. polyvinyl chloride or a polyolefin, or a thermosetting resin containing a heat sensitive curing or crosslinking agent. The tube may be reinforced by a woven web embedded therein in which the warp extends longitudinally and is of low elongation (e.g. stretch oriented polyester or polyamide or glass fibres) and the weft extends peripherally and is of high elongation (e.g. unstretched polyester or polyamide filaments or yarns). A heat sensitive adhesive may be applied to the inner surface of the pipe B and/or to the outer surface of the tube 8. The tube 8 is applied by inserting the tube 8 in collapsed condition into the pipe B, clamping the ends of the tube 8 between pipe end flanges 6 and end plates 9, 9<SP>1</SP> and expanding the tube 8 by hot pressurized air by means of heater 10 and pump 11. The method may be applied to the lining of new pipes before installation or to the repair of damaged pipes in situ as shown, e.g. underground pipes such as sewer pipes or mains for water, gas and utilities. [GB1416947A]

Description

METHOD AND APPARATUS FOR LINING A PIPE ambient foundation or earth movements resulting from many causes, corrosion and erosion, and many other ly maintain the service afforded by underground pipe, any serious leaks must be prompdy detected and repaired, and such repair generally requires the replacement of a long length of large diameter pipe, since the repair of a section of the pipe by welding, patching or otherwise, is usually unsatisfactory and very difficult. However, particularly in the case of underground ?ip<=> the replacement of the pipe is difficult, expensive and highly time consuming and hence greatly inefficient, since structurally the pipe is still sound overall and except for weak areas and the: points of rupture, still possess a long life expectancy. Not only is it necessary to dig a trench along and beyond the full length of the pipe section to permit its replacement, but the transport of the large pipe to and from the site is difficult, expensive ! and time consuming, as is the handling and manipulation of the i which necessitates the use of heavy crane equipment. Accordingly,1 the common practice in the maintenance and servicing of under- i ground pipes and mains is expensive, time consuming and difficult j and otherwise leaves much to be desired. ! I SUMMARY OF THE INVENTION j It is a principal ob ect of the present invention to j provide an improved process for repairing damaged or defective pipes, conduits and other tubular devices.

Another object of the present invention is to provide an improved method and apparatus for repairing leaks in large diameter fluid carrying pipes, conduits and mains.

Still another object of the present invention is to provide an improved method and apparatus for repairing leaks in underground or otherwise difficult accessible pipes, conduits and mains.

A a method of t e above nature characterized y its simplicity, ease of application, reliability, low time consumption, obviatio" of the need for skilled labor and great versatility and ad abilit The above and other objects of the present invention 1 will become apparent from a reading of the following description ! taken in conjunction with the accompanying drawing.

In a sense the present invention contemplates the provision of an improved method for repairing a leaking pipe J i which includes the step of disposing in and along a section of ! the pipe having the leak a tube of a synthetic organic polymeric ! resin composition, introducing gas under pressure into the tube j while in a soft state to expand the tube into tight engagement j with the inside face of the pipe, and then effecting the harden- j ing of the repair tube while in its fully expanded state. The j resin composition may be thermoplastic, for example, a thermoplastic polyvinyl chloride or polyolefin or the like, or may be an uncured soft thermosetting resin containing a heat activating | curing agent or a curing agent and a heat deactivating curing J retarding agent. Exampi-ee--o-£--aui-t-efe1e--fcher-fao-se-fctin--ccwap-o&ition£, are--d ecri-bed--in-e -pendi»g-ϋν-S - atent-Applcaion- SJ≥Xia1 It.; has been suggested to employ a. o l&h,-146--£il-^-&p-feemi>e-s-l&-r-197-1.—In-th±-S-rfl¾e a thermoplastic resin repair tube,-i-s--emlo ed, after it is heated and expanded it is advantageously permitted to cool before the W pressure therein is relieved.and- where a thermosetting resin tubi> is employed, the pressure and heat are maintained until the tube has set. The outside face of the tube or the inside face of the pipe may have an adhesive applied thereto, preferably a temperature sensitive adhesive to assure a suitable bonding of the pipe and tube at their interface. The repair tube is advantageously reinforced with fibers of a natural or synthetic A nature,' for example, polyester, polyamide, glass fibers or ( the like. Advantageously the fibers extend peripherally and longitudinally with the peripheral fibers having a high irreversible elongation whereas the longitudinal fibers are of low elongation. Preferably the repair tube has inbedded therein for reinforcing a woven web in which the warp extends longitudinally and is of low elongation, and the weft extends peripherally and is of high elongation, for example, unstretched or lo stretched, polyester or polyamide filaments or yarns.

A most important feature which characterises the present invention and which has neither been described nor suggested before, is the sufficient peripheral extension of the tube to non-reversibly elongate the perpheral fibers embedded therein which have a high non-reversible elongation. This critical parameter is accompanied by many important advantages which are lacking when conventional plastic tubes or conventional fiber reinforced tubes are employed, where tubes without reinforcements are employed and are lacking in strength they know have to be of great wall thicknesses and accordingly would significantly reduce the inside diameter and the pipe capacity. Where conventional fiber reinforced tubes are used, the tube periphery cannot be appreciably extended without rupturing the reinforcement, and hence, the tube, thereby greatly limiting its application and the quality of the end' result. Moreover, even with small peripheral extension, an internal stress is imparted to the tube.

The present method overcomes the drawbacks of the prior methods. The use of the fiber reinforced tube in which the peripheral fibers have high BOJa-¾'e¼¾iv eia le elongation results in a thin walled high 43417/2 of ruptured underground pipes* such as mains* Man or access holes* when not present, are dug at opposite ends of the ruptured pipe sections after the pipe has been suitably emptied and the section is uncoupled from adjacent sections to provide access to its interior* The collapsed is repair tube/inserted into the cleaned pipe and clamped by end plates to the pipe end flanges and hot pressurized fluids, for instance, air, is then circulated through the tube until it expands, and if informed of a thermosetting resin composition, until it is cured or set* The end plates are then removed and the repaired pipe section is recoupled to the adjacent pipe sections* In the case of sewerage pipes, man holes are generally present at opposite ends of successive pipe sections so that δαψ- digging or coupling and uncoupling operations are not necessary* Moreover, the present lining method may be applied to undamaged pipe before the installation or laying thereof. The procedure is simple, reliable and rapid and requires little skilled labor*' BRIEF DESCRIPTION OF THE DRAWING - 4a Figure 1 is a fragmentary transverse sectional view of a repair tube employed in the present improved process; ^ Figure 2 is a longitudinal sectional view of a ruptured underground main preparatory to its repair ;and Figure 3 is a view similar to Figure 2 illustrating a step in the repair procedure and the improved equipment employed therein .

DESCRIPTION OF THE PREFERRED EMBODIMENT [ Referring now to the drawing which illustrates a preferred embodiment of the present invention as applied to the repair of underground pipes or mains, the reference letter A generally ! designates the liner or repair tube and the reference letter 3 first section designates a damaged underground main/covered by overlying and normally flange connected between adjacent undamaged m.ain. second ater 'iaol 12-- /inu ~ the<= c kuonuvvcentkiuonuaali. m uiaaniuniecri,, t khitee m itiaateria al 1Z b ueciknugg — £ (sSeecCj!tt paved or unpaved, depending on its location. The pipe B in its unprepaired state, is shown as having a rupture or leak opening 4 i with ragged inwardly depressed borders 4' , the debris 5 from the j rupture 4 being accumulated on the bottom of pipe B underlying i the rupture 4. j The repair or line tube A includes a body or matrix 3 formed of a thermoplastic resin or of a soft thermosetting resin J i composition of the nature set forth above and having a latent j i curing or cross linking agent. An example of a suitable resin composition in a latent thermosettable state is as follows: Ingredient Parts by Weight Polyvinyl chloride esin 100 Arylester Thermosetting plasticizer (Tetraethylene glycol dimethacrylate 40 Diiso octyl phthalate 20 Stabilizer (Cd.Ba stearate) 3 Thermosetting initiator (Di-t-butyl perbenzoate) end flanges 6, suitable means being provided for releasably hermetically clamping the end plates 9 and 9' to respective ^ flanges 6, for example, the end plates and flanges may be provirl-. i ed with correspondingly spaced apertures for accommodating bolts': to effect their tight interconnection. A portable air heating ' unit 10 of conventional construction has n outlet connected by aj i flexible hose to the aperture in end plate 9 and an inlet conneccj ed to the outlet of a motor driven air circulating blower 10 whos! inlet is connected by a flexible hose to the aperture in the o he: end plate 9'. Conventional means are provided for regulating thej temperature of the circulating air produced by the heating unit j 10 by controlling the unit 10 in the known manner and means may be provided for introducing additional air into the circulating system to increase the pressure therein in the event that the hea expansion thereof is insufficient to fully expand the tube A and ! the pressure may be otherwise regulated. i i In applying the tube A, whose outside diameter is con- j i siderably less than the inside diameter of tube B to the inside face of pipe B, a section 8 of tube A is inserted along the length of pipe B and its opposite ends are expanded and the end borders turned outwardly to form end flanges which are sandwiched and clamped between end plates 9 and 9' and respective pipe flanges 6 and the end plates are clamped to the flanges 6. The heating unit 10 and the blower 11 are then energized to heat and circulate air through tube section 8 to expand the circulating air which may be further pressurized by pumping additional air therein, the heated circulating air at increased pressure expanding the tube irreversible/ > _ . section 8' and on^recovegab^y elongating the peripheral fibers 3 so that the expanded tube section 8 firmly hugs and adheres to the inside face of pipe B, scaling the rupture 4 as well as the

Claims (1)

1. 43417/4 WHAT IS CLAIMED IS: l.i The method of lining a pipe comprising Inserting In said pipe a synthetic organic·polymeric resin tube having reinforcing fibers of high non-reversible elongation embedded therein* such fibers extending peripherally, of such resin tube, the said resin tube having an outside diameter smaller than the inside diameter of said pipe, expanding said tube and irreversibly elongating said fibers while said tube is in a soft flexible condition to force said tube into tight engagement with the Inside face of said pipe by means of a pressurized fluid within said tube, and relieving said fluid pressure and cooling said tube while in engagement with said plpe»i < 2. The method of claim 1 wherein said tube is formed of a heat setable thermosetting resin composition, and said pressurized fluid is heated and circulated through said tube until said resin is substantially set.i 3.» The method of claim 1 wherein said fibers are comprised in the filler of a woven web embedded in said tube*1 4*i The method of claim 1 comprising applying end plates to the ends of said pipe, and clamping the end borders of said tube between said end plates and corresponding bent off borders of said pipe and circulating a heated gas through said tube by way of openings in said end plates, thereby irreversibly expanding the said tube.* 5*i The method of claim 1 comprising applying an adhesive - 9 - to at least one of the confronting peripheral faces of said pipe and said tube prior to the expansion of said tube. », | - I i I β. 6. The method of claim 1 wherein said resin is ther^mo-plastic. i % 1. The method of claim 1 wherein said pipe includes a first underground section "atTd" coupled at opposite ends to adiacenii in the ground second pipe sec ions,and including the steps of digging holes «t j the opposite ends of said first pipe section and uncoupling said ! first section from said second section* to provide access to said first section and inserting said tube into said first section prior to the expansion of said tube. 8. An apparatus for practicing the method of claim 1 comprising a gas heating and circulating means having an inlet and an outlet, a pair of coupling plates having p!arts therein and means including flexible hoses connecting said inlet and outlet to respective ar-s-. ,-,,,^ P.0. Box 33116 , Tel-Aviv Attorneys for Applicant