How Safe Are Flanges?

Jon Lawson

Welding is still the most widely recognised method for joining pipe systems together. However, there’s an additional connection technology that is worth considering: the High Performance Flange (HPF) system.  Ramiz Selimbasic details this time-saving and cost saving alternative to welding.

What Is The High Performance Flange (HPF) System?

The High Performance Flange (HPF) system is coordinated to common pipe sizes from 25 to 150mm diameter and wall thicknesses up to 20mm. It is designed for flange sizes ¾ to 5in hole patterns according to ISO 6162-1/2 (Code 61/62), ISO 6164. High-performance flanges are manufactured as finished machined and type approved according to International Association of Classification Societies (IACS). This therefore results in consistently high precision and quality during processing, so that these components no longer have to be reworked at the installation site.

The best solutions for complex design problems can often be found in nature. The flaring of a tube is similar to the shape of a branch where it joins the trunk of a tree. The tube is flared by hydraulic axial pressure giving it a parabolic shaping, increasing from 10° up to 37°. The initial gentle incline of the shaping guarantees additional safety against strong system vibrations.

The most essential part of the HPF connection is the locking flange design, which supports the pipe from the outside and provides additional protection against it tearing out of the connection. An insert is placed into this specially formed pipe. This insert seals on the connection side either via a special profile seal or an O-ring and on the pipe side via an O-ring. The insert has no toothed contour, which thereby makes repeated assembly work possible without any problems.

The Benefits Of The High Performance Flange (HPF) System?

This HPF principle results in a series of practical advantages as Hans de Lang, production manager at Royal IHC, confirms. In addition to ship construction, the company, which has been in existence since the 17th century, also manufactures pipe systems and accessories for the offshore market and has been using the HPF system.

“The system is universal for working pressures up to 420 bar and is therefore a versatile application method. As we provide solutions for the offshore and underwater markets, this aspect is very important for us. In contrast to conventional O-rings, the special profile seal is particularly resistant to gap extrusion,” says de Lang, thereby highlighting an aspect that is important for his area of responsibility.

“The HPF system is comparatively compact. This refers to the minimum length from the connection to the starting point of the pipe bend. Since we always implement designs that only permit little space and play, the HPF system is a very helpful product for us. Our fitters and assembly workers appreciate the fact that, unlike other mechanical flange systems, HPF inserts can be easily replaced if damaged during installation and pipe forming can be done on site. Also, bolts and screws can be easily tightened even under difficult conditions. All in all, high performance flanges have proved themselves to be tear-proof and vibration resistant. Safety plays a very important role for us,” says de Lang.

Returning to the welding technology mentioned earlier, this traditional technology is comparatively time-consuming, because heavy wall pipes connectors require several layers of welding and must be made by qualified welders. All welds have to have an X-ray inspection and the pipe systems must be flushed through. These intermediate steps can be omitted when using the HPF system, which is also more environmentally friendly. The flanging process does not cause noxious gases, thus eliminating explosion and fire hazards.

How Safe Is The High Performance Flange (HPF) System?

Parker’s HPF components are supplied as standard with a highly corrosion-resistant surface – an aspect that plays an important role across all industries. This surface finish is also free of CrVI, which is suspected of causing cancer.

“Parker always provides a comprehensive service package from design, production and on-site installation that the end customer can take advantage of. But this is not binding on what we can provide. For example, we can also execute pipe end forming ourselves on site with an assembly machine, which makes us even more flexible”, says de Lang. Explaining how the Parker Parflare HPF 120/170 functions, he says: “The machine is used for pipe end forming in the axial pressing process for the HPF flange system. It is a workshop device for single piece production. The flanging contour is achieved by axial pressing of the tool into the pipe end. The contour of the flange is designed for use with HPF inserts.”

The tool’s feed-in movement is generated by a hydraulic cylinder driven by a unit in the machine housing. The return stroke is also executed as electro-hydraulic. The pipes are clamped in clamping jaw sets that are clamped over a cone. The machine is equipped with an adjustable stop end for the pipe end. This therefore produces flange contours of uniform quality. The separated clamping jaws and the pipe stop end enable easy handling and uniform results. The separation of the clamping jaws and the removal of the pipes is facilitated by a bracket. Another practical feature of the Parflare HPF 120/170 is that it can be moved quickly to any location on rollers or by fork-lift truck or crane. In summary, the high-performance flanges can be assembled easily, quickly and, above all, safely.

Ramiz Selimbasic is with Parker


Recent Issues