3 or 4 Bolt Flanges Designed to ASME VIII Appendix 2

[MrVessels]

Does anyone have direct experience of designing and operating 3 or 4 bolt large diameter flanges (up to 50 inches) especially with respect to determination of flange leakage?

These flanges are on vessels in radioactive service and mate to rotating equipment which must be removed by remote handling equipment, hence the limit on the number of bolts.

The gaskets are EPDM O-rings held captive in grooves on the flange, so gasket seating is not a problem and the design pressure is only 15 psig so the size of the bolts also is manageable.

However the potential for leakage of the joint is of concern and I'm looking for allowable flange deflection recommendations based on successful operating experience.

 

[arto]

They used to say "use 'pi-spacing' between bolts to avoid leakage problems" i.e., ~3-1/8" between bolts, or number of bolts = BCD in inches [sometimes rounded up to the nearest multiple of 4 to straddle cL's]

There's an old Machine design article on the subject for regular gaskets: D.V.Cook & B.G.Guerreri, "Deflection in Gasketed Joints," Machine Design, March 14, 1968, pp.149-150.

How about a Gray-Loc type connection? they only have 4 bolts, take up less radial space, & maybe lighter wgt they go up high in pressure too

http://www.grayloc.com/

[see Sec. VIII Div 1 App 24 for calc's.]

If it's for Low pressure, how about Tri-Clover or Cherry-Burrell type segmented clamp fittings?

http://www.tri-clover.com/products/fittings/triclamp.htm

http://www.gowcb.com/products/fitting.htm

Once we used Aeroquip Marman Clamps

Helicoflex makes segmented clamps [almost like a chain] that cover a large diameter range.

http://www.helicoflex.com/zztechnicalqds.htm

 

[vesselsanonymous]

I have experience with design of 3 bolt flanges at both Idaho and Hanford facilities. I do not have any experience with evaluating leak rates or potential leakage rates. Call 949-349-3559