AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant: Rinker Australia Pty Ltd Invention Title: Jointing System for Pipe Lining The following statement is a full description of this invention, including the best method for performing it known to me/us: -2 TITLE: JOINTING SYSTEM FOR LINING ON CONCRETE STRUCTURES Introduction The present invention relates to a jointing system for 5 lining on concrete structures as well a method for jointing lining. Background of the Invention Lining is often applied to flat or curved concrete 10 structures to protect the concrete from damaging elements. For example, lining applied to large gas and liquid pipes, such as concrete sewer pipes, serves as a barrier for the concrete structure to fluids within the pipe, and particularly protects the concrete from the sulphuric acid 15 generated by the hydrogen sulphide gas in the sewers which corrodes the concrete of the pipes. Linings are made from inert materials, usually plastics such as High Density Polyethylene (HDPE) and are typically 20 formed by extrusion. The linings are cast into the internal pipe surface at the time of casting the concrete pipe and are usually provided with integrally formed anchor knobs that are cast into the concrete to secure the lining against the concrete surface. 25 Linings must be continuous along the installed pipeline to protect concrete both in the pipe barrel and at the pipe joints. In order to form the desired continuous lining barrier across the joints to prevent liquid or gas 30 penetration, the plastic lining at the joint is joined by a plastic welding process which occurs after the pipes have been laid and requires welders to work inside the installed pipeline. The continuous lining barrier along the pipeline prevents escape of hydrogen sulphide gas from 35 the pipe barrel into the joints and thereby eliminates the potential for concrete corrosion. N:Welboume\Cases\Patent\71000-71999\P71050.AU. \Specis\P71050.AU. ISpecification 2007-12-17.doc 19/12/07 -3 There are, however, constructional problems with ensuring a continuous barrier along the pipe barrel using known techniques. The welding process must necessarily be carried out inside the installed pipeline which means 5 working in confined pipe spaces which in turn increases the risk of occupational health and safety problems. Furthermore, the welding process is time consuming, leading to higher labour costs and often lower quality work than work otherwise carried out in the controlled and 10 safe environment of a factory. The present invention provides a more efficient and cost effective system for jointing pipe lining. 15 Summary of the Invention In accordance with the present invention there is provided a jointing system for lining on concrete structures comprising: edge linings for internally lining the ends of 20 adjacent concrete elements to be jointed together to form a structure, the edge linings being continuous with main lining on the structure, wherein the edge linings have anchoring means to anchor the edge linings to the element ends, and having interlocking means; and 25 a cover strip for bridging the edge linings on adjacent elements and having a second interlocking means capable of coupling with the first interlocking means to create a joint between the pipes. 30 Preferably, the edge linings are each provided with a raised continuous key which contains a recess on an underside of the edge lining, the recess defining the first interlocking means. The key contains a protrusion on an opposite side of the recess which defines the 35 anchoring means. The protrusion is shaped to anchor the edge lining into the cast concrete element. The protrusion is arrowhead in shape. N \Mclboume\Cases\Patent\71000-71999\P71050.AU.I\Specis\P71050.AU.1 Specification 2007-12-17.doc 19/12/07 - 4 The recess in the key is preferably shaped to create a mechanical lock with the interlocking means wherein the width of a mouth of the recess is narrower than the 5 maximum width of the recess. Each edge lining may have more than one continuous key, such as two keys. The cover strip preferably has at least two continuous plugs located on one side of the cover strip wherein the 10 plugs define the second interlocking means which each interconnect with one key recess on each lining. The plugs are shaped correspondingly to the shape of the recess. There may be more plugs, where the number of plugs corresponds to the number of recesses across two is edge linings. The cover strip is also preferably provided with a concertinaed joint insert for locating in a space between the elements. 20 The edge linings are butt welded to the main lining to create a continuous pipe lining. Alternatively, the edge linings may be formed integrally with the main lining. 25 The edge linings and cover strip are preferably extrusions made from High Density Polyethylene material or other similar plastic material. The jointing system is preferably used in pipelines and is 30 sufficiently flexible to curve with the pipe radius. In a further aspect of the invention there is also provided a method of jointing lining on concrete structures including: 35 casting main lining into a concrete element used to form a structure and casting edge linings at ends of the element such that the main lining and the edge linings are N:\Mehoome\Cases\P'atent\71000-71999\P71050.AU. \Specis\P71050.AU.I Spccification 2007-12-17.doc 19J12/07 - 5 continuous, wherein the edge linings have anchoring means to anchor the edge linings to the element ends, and also have first interlocking means; laying and jointing the elements end to end; 5 bridging the edge linings between adjacent elements by coupling a second interlocking means provided on a cover strip with the first interlocking means to create a joint between the elements. 10 The method also preferably includes butt welding each edge lining to the main lining to form a continuous lining surface. The first interlocking means is preferably a raised key 15 with a protrusion and a recess. The method further includes filling the recess with a rubber strip during casting. The rubber strip will eliminate concrete materials from entering the recess that 20 might then prevent proper insertion and location of the protrusion. The method is preferably applied to pipelines. 25 Brief Description of the Drawings An embodiment, incorporating all aspects of the invention, will now be described by way of example only with reference to the accompanying drawings in which: 30 Figure 1 illustrates a jointing system for lining on concrete structures in accordance with an embodiment of the present invention; and Figure 2 illustrates the jointing system in situ. 35 N:\eIlboume\Cases\Patnt\71000-71999\P71050.AU. I\Spccis\P71050.AU.I Specification 2007-12-17.doc 19/12107 - 6 The Description of the Preferred Embodiment A jointing system 10 for internal pipe lining is illustrated in Figures 1 and 2. In the preferred embodiment illustrated the jointing system 10 is used 5 typically to line the joints between concrete pipes, such as drainage pipes and sewer pipes. It is however understood that the system may be used to close joints between other concrete structural elements where the joint between the main surface lining on the elements is 10 required to be closed over or sealed to form a barrier against fluids. The jointing system may be used on flat or curved elements, for instance on concrete buildings. The present jointing system 10 comprises two edge linings 15 20 to be fitted to each adjacent end of adjacent pipes 11, and a cover strip 30 that bridges together edge linings 20 so as to, in the case of sewer pipes, create a barrier against corrosive gases for protecting the concrete. 20 In a preferred embodiment of the invention as illustrated in Figure 2, the interior 13 of concrete pipes 11, are lined with main internal lining 12 during the casting process. Main lining 12 is made of an inert material, typically a flexible plastics material having some 25 rigidity such as high density polyethylene (HDPE) or polypropylene, or similar. Main lining 12 is extruded with integral anchor knobs 14 cast into the concrete to anchor the lining against the concrete surface. 30 In the preferred embodiment internal lining 12 is cast into each pipe 11 in a manner to fall short of the pipe ends 16. The internal circumferential surface of each pipe end 16 is instead cast with edge linings 20. Edge lining 20 are cast into each pipe end of the concrete pipe 35 during the casting process together with internal lining 12 In the application of sewer pipes the edge lining is typically 100mm in width. N:\Melboume\Cases\Patent\71000-71999\P7l05O.AU. I\Specis\P7I050AU. I Spcification 20D7-12-17.doc 19/12/07 - 7 Edge linings 20 include a planar surface 28 with continuous keys 22 raised from the surface 28 along the length of the edge lining. The keys 22 are similar to 5 anchor knobs 14 of main lining 12 in that keys 22 function to anchor an edge lining 20 into the concrete pipe. Continuous keys 22 protrude from the surface of the edge lining 20 with the protrusion side of the key shaped in an arrowhead 24 to form the anchoring means of the edge 10 lining. The underside of the key 22 is recessed to form the first interlocking means, a recess 26. Recess 26 is shaped to create a mechanical lock with a corresponding, second, 15 interlocking means provided on the cover strip in the form of a continuous plug 32. In the embodiment shown one key 22 protrudes from the planar surface 28 of each edge lining. It is however, understood that more than one key may be provided for each edge lining. 20 The keys are continuous on the edge linings in that they form a continuous ridge along the extruded edge lining. This ensures that, as illustrated in the jointed pipe partial section view of Figure 2, when the jointing system 25 is in place a continuous mechanical and gas tight lock is created along the entire pipe circumference at the end of each pipe 11. Recess 26 is shaped such that the width of a mouth 27 of the recess 26 is narrower than a maximum width of the recess. In the embodiment shown the recess 30 is substantially diamond in cross sectional shape. During the casting process, rubber strips (not shown) are inserted into recesses 26 to maintain recess integrity and shape and keep out concrete materials, which may be 35 compromised as concrete is poured and sets. N:\Melboume\Cases\Patent\71000-71999\P7l050.AU.\Specis\P7105O.AU.I Specification 2007-12-17.doc 19/12/07 - 8 Cover strip 30 is designed to bridge together two edge linings, each provided on an adjacent pipe end. In the embodiment shown, cover strip 30 includes a raised joint insert 34 that is formed in an extruded folded peak on the 5 cover strip. In use, joint insert 34 locates in a gap 18 between installed adjacent pipes. In some applications, for example with flat concrete structures, there may not be a gap between the structural elements and in this case the cover strip 30 would not have a concertinaed joint 10 insert. The concertinaed joint insert allows for future expansion or contraction of the joint without affecting the integrity of the cover strip and its connection into the 15 edge linings. This concertinaed joint insert also provides dimensional variation to accommodate variation in distance across the joint and between the recesses in the edge linings. 20 On either side of the insert 34 is a planar surface 36. Protruding forward in the same direction as the peaked insert 34 and on either side of the insert are the continuous plugs 32 designed to couple with the first interlocking means, the recess 26. Plugs 32 are spaced 25 along cover strip 30 to align with recesses 26 on adjacently positioned pipes 11 when the pipes are laid and jointed and separated by the correct spacing, which in the present application would be a spacing of approximately 10- 35mm.. 30 Plugs 30 press fit into recesses 26. Since cover strip 30 is extruded from a flexible plastics material, typically also HDPE, plugs 32 will deform under a force, such as hammering to press fit into recesses 26. Plugs 32 are 35 similarly shaped to recesses 26 and, in the embodiment shown, the plugs are approximately diamond in shape. N:\Melboume\Cases\Patcnt\71000-71999\P71050 AU. \Specis\P7105O.AU.I Specification 2007-12-17.doc 19/12/07 - 9 Joint insert 34 is designed to ensure that the lining between adjacent pipes 11 remains continuous across gap 18 yet allows for expansion and contraction of gap 18 between pipes 11 as a result of ground movement. Joint insert 34 5 achieves this by its folded nature allowing the joint insert 34 to expand and contract. The planar surface 36 of cover strip 30 has tapered ends 38 which, in use, prevents the fluid and suspended solids 10 flowing through the pipeline from fouling the cover strip 30 and lifting it off the edge linings 20. Tapered ends 38 direct fluid and suspended solids to flow over the cover strip and prevent any tendency for the cover strip to lift. 15 Edge linings 20 are embedded in the end of each concrete pipe during casting and are laid at the same time as the main lining 12, which lines the majority of the internal pipe circumference. Once set into the pipe the join 40 20 formed between the main lining 12 and each edge lining 20 is butt welded by a standard plastic welding process to provide a continuous, waterproof and gap-tight lining surface. Edge linings 20 are cast such that their edges are substantially level with the end of pipe 11. The 25 welding process takes place off-site in controlled factory conditions. Prepared with lining, the concrete pipes 11 are transported to on-site for laying and jointing. Once laid 30 and fixed into position the gaps 18 between each adjacent pipe are closed to the pipe interior by bridging cover strip 30 across the gap and coupling the cover strip 30 to edge linings 20 on either side of the gaps, with joint insert 34 located in gap 18. With edge linings 20 locked 35 to cover strip 30 gas nor liquid is able to escape through gap 18 from the pipe interior 13 by leaking between edge linings 20 and cover strip 30. The jointing system may N:\M lbourneXCases\Patent\71000-71999\P?7050.AU. \Specis\P7I05O.AU.1 Spccifeation 2007-12-17.doc 19/12/07 - 10 not necessarily provide a liquid-proof joint, as some applications need only a gas barrier or lock. But it is envisaged that the jointing system could also form the basis for a sealed joint. In a further embodiment the 5 plugs 32 may be electro fusion welded into the recesses 26 after insertion. A wire could be extruded with the cover strip 30 with the wire running through the plugs 32. After coupling the cover strip onto the edge linings, a current is run through the wire in the cover strip which melts the 10 plugs, fusing them into the recesses. Because of the fluid tight lock created between edge linings 20 and cover strip 30 there is no need for any welding of the lining once the pipes are laid in position. 15 This reduces the time spent by workers in uncomfortable and potentially hazardous conditions within the laid pipes. Rather than welding lining from inside a laid pipe, which is time consuming and prone to inaccuracies, the present jointing system requires workers to simply 20 hammer the cover strip 30 into the edge linings to thereby quickly create an effective mechanical gas tight joint between pipes 11. With the present jointing system most of the preparatory work is carried out in the factory while on-site the joint lining can be applied quickly. 25 This decreases the overall time taken and cost to install pipes because with known welding techniques the pipeline must be laid first before workers can access manholes to finish off jointing the lining by welding. With the present technique jointing of lining may be carried out 30 concurrently as the pipeline is laid. The jointing system can be applied to large diameter pipes, such as sewer pipes that generally have a diameter of between 600 mm to 4000 mm .However the system may also 35 be used where lining is applied to pipes of diameter less than 600mm where the cover strip can be inserted remotely without man entry into the pipe. N:\Melboume\Cases\PatentI71000-71999\P71050.AU. \Specis\P7i050.AU.I Specification 2007-12-17.doc 19/12/07 - 11 It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention. 5 In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as 10 "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. N:\Melboume\Cases\Patent\71000-71999\P71050.AU.I\Specis\P71050.AU.1 Specification 2007-12-17.doc 19/12/07