www.fogt.com V003-01-2014

Easier bolt alignment and reduced installation time

ASME Swivel flanges

Description & application use

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 all piped applications Swivel Flanges can save considerable

installation time. Freudenberg Oil & Gas Technologies (FO&GT) provides a full range of swivel flanges to

suit all classes of ASME B16.5 (sizes24) flanges. All FO&GT flanges benefit

from the extensive experience that FO&GT has gained in over 25 years of flange design, develop-ment and manufacture.

There is no international standard for swivel ring flanges and

this can lead to under design on a fundamental level. Whilst

the ASME 16.5 and 16.47 codes are applicable for weld neck

flanges, they are not applicable to swivel ring flanges beyond

the bolt pattern and bolt sizes. ASME offer alternative rules

that consider swivel ring flanges as non-standard, or loose type

flanges, but detailed design and Finite Element Analysis (FEA)

has to be conducted to ensure components are not undersized

or over stressed.

The effect of undersized or lightweight designs can often

be seen on site with deformed and bent swivel rings which in

turn results in bending of the bolts and potential loss of gasket

seating force.

Care must also be taken to avoid mismatch between the flexural

properties of the swivel flange and the mating weld neck

flange. By ensuring these properties are well matched, an even

compression on the sealring is obtained, thereby minimizing the

opportunity for bolts to be overtightened during installation.

Freudenberg Oil & Gas Technologies removes these potential

modes of failure at the design stage, preferring to manufacture

the swivel rings using high strength carbon steel, with a design

process supported by in-house software and FEA. The hub

would be manufactured to the customers mating material

specification.

FO&GT swivel flanges also feature a stainless steel retaining

circlip that holds the swivel ring in place during assembly. This

can be easily removed and refitted, allowing the swivel ring

and hub interface to be lubricated for easy rotation during

installation. This circlip replaces more complex retaining

methods such as welded retainer clips.

Are all Swivel Flanges designed the same ?

Recessed metal retaining circlip providing full flange face for bolt tensioners.

360 rotational swivel ring to simplify bolt alignment

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Material

Swivel Flange hubs can be manufactured from materials

to suit any pipe network. FO&GT has experience in the

production of connectors from carbon steel, Duplex,

Super Duplex, Stainless Steels, Nickel Alloys and specialist

materials. Swivel rings are made from high strength carbon

steel. Swivel flanges hub can be supplied with Nickel Alloy

or stainless steel inlay to the seat areas when necessary to

meet erosion or corrosion requirements.

Bolting

Bolt sets for swivel flanges are supplied to meet the clients

specifications. Longer bolts are required compared to weld

neck flanges to accommodate the increased thickness of

the swivel ring. All materials, coatings and types of bolting

can be supplied. Customer to advise if bolt tensioning will

be used.

Coating

A wide variety of coating and paint systems are available

using our in-house blasting and coating facility.

62,273 mm

Cut view of Swivel Flange

Swivel Flange Features

Large blend

radius to match

pipe section.

Special flange facings

available to reduce

bolt bending and

improve bolt tensioning. For further details contact FO&GT.

Optional environmental seal available.

Robust swivel ring design based on FO&GT rules that exceed ASME

requirements. High strength Carbon Steel as standard.

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Standard weld prep. Special weld preps available.

Optional weld overlay (CRA) for seat longevity and for use with

stainless steel gaskets.

Recessed metal retaining circlip providing full flange face for bolt

tensioners.

Robust swivel hub design. Hubs assessed for hydrostatic design

pressures and external loads. Hub material to suit client pipework.

Fillet radius on swivel hub to reduce stress concentration at shoul-der interface whilst maintaining low bearing contact stress.

RTJ grooves or flat facings to suit client applications. Custom seal

profiles or non-standard RTJ gaskets can be accommodated if

required.

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