Leak-free high-pressure piping systems

Paul Boughton

Esa Ranne explains that the right connection technique, accurate prefabrication and solid pipe support are the key factors that ensure leak-free piping.

There are three major factors that must be managed in the planning and installation of leak-free systems. Firstly, the right connection technique must be selected. Secondly, a single prefabricated tube has to be dimensioned accurately enough. Finally, the supporting of the pipes must be solid enough. When these three factors are realised, the piping will be tensionless and stable, and there will be no excessive strain on the joints.

GS-Hydro uses non-welded connection technology and delivers leak-free piping systems around the world. 3D technology offers a design according to provided diagrams and layouts. Strain (such as thermal movements) directed on fittings, clamps and piping can be estimated beforehand.

Choosing the right connection

The company's GS-flange connecting system covers tubes with an outside diameter of 16 to 609mm, the highest allowed operating pressure being 690bar. The standard production materials are carbon steel (zinc electroplated or hot dip galvanised) and stainless steel.

When the wall thickness of the high-pressure pipe is less than 7mm, the flange is locked to the pipe by 37° flaring. When the wall thickness exceeds 8.5mm, the flange is anchored with a retain ring. The non-welded GS retain ring technique enables tubes with a diameter of 350mm and a 350bar nominal pressure. When the pressure is less than 40bar, GS-Hydro applies the 90° flaring technique. The wall thickness can then be a maximum of 11mm and the tube diameter a maximum of 609mm.

The benefits of the GS-flange connection can also be seen with smaller size tubes. One benefit of the GS-flange with an outside diameter of 20 to 50mm compared to a fitting connection (eg, DIN, JIC) is their smaller size and, above all, lower tightening torque, which keeps the installation space reasonable.

Accurate dimensions

GS-Hydro delivers prefabricated tube modules to the site, which are joined together for a complete piping system. This is done by, for instance, cold forming or machining instead of welding. Therefore, there will be no tension focusing on the material decreasing the dimensional accuracy.

Cleaning the insides of the tubes is easy and there are major time savings as the installation time for a high-pressure connection can be made, on average, in a couple of minutes with the GS-Hydro technique. Additionally, the prefabricated pipes with bending, coatings, stampings, fittings, etc. can be fabricated in advance in workshops with the ideal machinery and by professional personnel. Together, this means that the cost savings are significant compared to welded piping fabricated at the installation site.

For more information at www.engineerlive.com/iog

Esa Ranne is with GS-Hydro Finland in Hämeenlinna.

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