TPi January 2008

f i t t ings feature on . . .

Fittings in PPSU Valsir, Italy, is a specialist in the technology of multilayer pipes and crimp-fittings. The company’s Pexal- easy is an advanced system of fittings made of Polyphenyl Sulfone (PPSU). The material’s characteristics make the new Pexal-easy fittings equal in performance and quality to brass fittings. The elevated mechanical characteristics (including tensile strength and modulus

of elasticity) exceed those of normal polymers, and are similar in performance to metal fittings, withstanding accidental or deliberate blows, either at low or high temperatures. The body of the fitting, the nuts and the threads are all made from PPSU. Pexal-easy also possesses elevated ageing resistance that is maintained even at high temperatures. The structure of the fittings is immune to chemical agents, and it can therefore be laid in grooves or in surface mounting.

Connection between the pipe and the fitting is carried out easily, reducing the laying times. An innovative system that locks the nut onto the fitting ensures a firm connection with the pipe, eliminating the possibility of error, and the base of the thread features a special anti-loosening profile.

Pipe coupling makes Portuguese re-lined main leak-proof

An example of the use of Valsir’s Pexal-easy pipe fittings

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The fitting can be reused without having to replace the o-rings or the nut. Unlike other systems, with Pexal-easy there is no reduction in the bore when passing from the pipe to the insert, meaning a significant reduction in pressure drops. Where a 5 / 8 " pipe was required, with Pexal-easy it is possible to use a 1 / 2 " pipe.

Lisbon water company EPAL has employed a specialist coupling developed by Viking Johnson, UK, for terminating pipes that have been re-lined with a thin-wall PE liner. The DN800 LinerGrip couplings for the rehabilitation work – on a concrete main at Ota, 50km north of the city – were ordered by Portuguese contractor Vacqualiner, which is using the Subline Æ system under licence from British company Subterra and in cooperation with Dutch company BAM Nellis Infra. Explaining the reasons for the choice of LinerGrip, Vacqualiner’s Hugo Santos said, “We needed to be confident that the PE liner was fully supported and held firmly in

Valsir SpA – Italy www.valsir.it

Simulation software helps save time in valve design

Viking Johnson’s LinerGrip has been used by Portuguese water company EPAL

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place when we returned the main to its operating pressure. This is particularly important when using thin-wall liners, because they rely on the strength of the host main and couplings for pressure retention.” Other successful applications of LinerGrip include 2.5km of concrete main through the historic centre of Haarlem in the Netherlands, and a 9km cast iron supply main to a service reservoir in the UK. LinerGrip has an in-built gripping arrangement to hold the PE liner and prevent it retracting inside the host main due to changes in temperature or the Poissons Effect. It also provides a flanged end for connection to other pipework in the make-up piece. The support provided by LinerGrip prevents damage by the shear forces arising as it emerges from the host main. It ‘seals back’ onto the outside of the host, stabilising the entire fitting and preventing the ingress of ground water into the annulus between host and liner pipes. Corrosion protection is provided by factory applied thermoplastic polymer Rilsan Nylon 11, which meets the stringent performance standards of WIS 4-52-01 (Part 1) for the highest adhesion, flexibility, penetration and impact resistance characteristics. As a result, LinerGrip products are well equipped to withstand transport, storage, site and corrosion damage, eliminating the need for further protection such as on-site wrapping.

Ventrex Automotive GmbH, Austria, has saved four months in the design of an automotive valve, by taking advantage of EFD.V5 Catia V5-embedded computational fluid dynamics (CFD) simulation software. “In the past, we would have had to build and test at least 50 valves in order to get the design right,” said Peter Pfaffenwimmer, project manager for Ventrex. Daniel Gaisbacher, also a project manager for Ventrex, added that “CAD-embedded CFD made it possible to determine simulation results nearly as fast as we changed the design. The result is that we were able to improve the flow rate of our new valve by 15% while eliminating about 50 prototypes and reducing time to market by four months.”

Viking Johnson – UK info@vikingjohnson.com • www.vikingjohnson.com

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Tube Products International January 2008

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