WEST YORKSHIRE, UK, Feb. 01, 2008 -- Insituform Technologies Inc. (ITI) has a worldwide reputation as a leader in the development and global acceptance of the Cured-In-Place-Pipe or CIPP pipeline renovation technique. Insituform is a manufacturer of equipment and an experienced contractor, with extensive in-house expertise.
The UK subsidiary of ITI is Insituform Technologies Ltd (ITL) based in Ossett, West Yorkshire. ITL recently expanded its use of air pressure to invert a new liner into a pipe to a whole new level. The development has enabled ITL to produce a cost effective yet environmentally friendly lining system that takes both air inverted and steam cured installation capability up to diameters of 1,800 mm (1.8 m), out-sizing similar installation techniques which have previously limited this technology to much smaller diameters.
Background
Most air inversion techniques to date have utilised inversion drums or apparatus like Insituform's CHIP® Unit to achieve the liner inversion. The limitation with this is that, being confined within a drum or passageway, the maximum length and liner diameter that can be loaded is finite. So, in many cases, the upper limit for air inversion has been around 500 mm diameter. Whilst in most instances this is perfectly acceptable, circumstances do occur where it would be preferable to utilise air inversion lining at larger diameters.
The new ITL air inversion/steam cure system overcomes these limitations by removing completely the need to invert the liner from within the confines of an inversion drum.
Development
Insituform has used the results of development work undertaken some years ago to bring together modern higher 'spec' equipment to enable the new large diameter air inversion system to be developed.
In essence, the new system takes factory impregnated liner directly off the delivery truck on site, attaches it to the inversion unit and installs the liner without any need to confine it in any way. The inversion process effectively involves attaching the free end of the liner sock to an aperture that is best described as a 'gland'. The inversion process is started with the liner being inverted through the gland, which is designed to allow air pressure to be applied inside the inverted section. This pressure is maintained whilst the remainder of the liner is pulled through the gland using a specially designed sealing arrangement. The seal engages in a manner that allows movement of the liner through the gland whilst remaining tight enough the prevent the compressed air from escaping, forcing it to advance the liner in the only direction open to it, down the host pipe.
ITL has two such systems, one for medium diameter installations and one for larger diameter projects. Using the new systems enables liners of up to 1.8 m diameter to be installed, depending on the specific project circumstances.
When asked about the development of the new installation capability John Beech, Business Development Manager for ITL, said: "The development of the new inversion systems enables ITL to take the latest lining technology to a whole new level. Removing the diameter restrictions that we have previously encountered using air inversion projects opens up a major new market area for us. With the increasing demand for steam cure linings being driven by a need for faster installations, limited access to sites in terms of time and working space and improved environmental factors offered by the new technology in terms of styrene emissions, particularly in built up areas and high traffic density locations, the ability to offer larger diameter air inversion capability once again puts ITL at the forefront of the sewer renovation market."
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