Swivel Ring Flange sets consist of a butt weld swivel hub with a rotatable outer bolt ring which allows for easier alignment of the bolts to the mating flange. For both subsea and topside applications this can be an essential capability that can save considerable installation time.
Vector provides a full range of swivel flanges to suit all classes of ASME B16.5 flanges. All Vector flanges benefit from the extensive experience that Vector has gained over the past 20 years in flange design, development and manufacture.
Are all Swivel Flanges designed the same?
Superficially most swivel ring flanges look similar, however, there is no international standard for swivel ring flanges and that can lead to under design on a fundamental level. Whilst the ANSI 16.5 code is acceptable for weld neck flanges, it is not applicable to swivel ring flanges beyond the bolt pattern and bolt sizes. ASME offer no specific guide rules for the design of the swivel ring or the hub design, only alternative rules that treat swivel ring flanges as non-standard or loose type flanges. For this reason detailed design and FEA has to be conducted on all swivel ring flanges, or the components could easily be undersized and over stressed. The effect of undersized or so called “lightweight” swivel rings can often be seen on site with deformed and bent swivel rings which in turn cause bending in the bolts and potential loss of clamping force.
Another cause of potential failure is the mismatch of the flexural properties between the swivel flange and the mating weld neck flange. By ensuring these properties are well matched, even sealing on the sealring is obtained, thereby, minimising the opportunity for bolts to be over-tightened during installation.
Vector’s design philosophy is to remove these potential modes of failure and ensure there is minimal swivel ring bending and acceptable levels of stress. Vector achieves this by utilising in-house software and FEA design and with the use of appropriate high strength materials. It is for this reason that Vector’s preferred choice is to manufacture their swivel rings using high strength carbon steel. The hub can be manufactured to the customer’s mating material specification. Vector’s swivel flanges also feature a stainless steel retaining ring that holds the swivel ring in place during construction. This ring can easily be removed and then refitted after construction, allowing the swivel’s ring and hub interface to be lubricated for easy rotation during installation. This ring replaces more complex retaining methods such as welded retainer clips.
force.
Recessed metal retaining circlip
Swivel Flange features
Design Tools and Codes
• Custom in-house flange design software.
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• 2d and 3d FEA
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• The standard weld preparation is to
ANSI B16.5 (alternative preps can be
accommodated).
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• Design Codes: ASME VIII Div. 1&2,
ASME B16.5, API6A, API17D, DNV OS F101.
TestingFull assembly, FAT, pressure and bend testing facilities are available at our UK based design facility.
MaterialSwivel Flange hubs can be manufactured from materials to suit any pipe network. Vector has experience in production of connectors from carbon steels, Duplex, Super Duplex, Stainless Steels, Incoloy and specialist subsea materials. Swivel rings are made from high strength carbon and low alloy steels. A wide variety of paint systems and coatings are available using our in-house blasting and coating facility.
Bolting With swivel flanges the bolt sets are supplied to meet the client’s specifications. Longer bolt sets are required compared to weld neck flanges to accommodate the extra thickness of the swivel ring. All bolt materials, coatings and types of bolts can be supplied. Please state if bolt tensioning will be used.