The fabrication tolerances of piping connecting to rotating equipment are usually tightly controlled as any flange misalignment (esp. angular) will put excessive loads on the equipment. With large high pressure piping the required tolerances are usually difficult to achieve.

I have been asked if the use of “Taper-Lok” flanges can be used to compensate for any flange angular misalignment on initial boltup. Taper-Lok claim to take up to a 2 degree misalignment.

I have not seen or heard of this type of flanges used in this application. If anyone has any experience I would appreciate some references and feedback.

Regards

The Taper-Lok flange is like the high pressure lens ring flanges, in that the sealing element is not a flat sheet / spiral wound metal gasket, but is a double tapered conical element. The seal is made to the I.D. of the flange bore which has similar taper to the conical ring. The ability to allow small angles of mis-alignment is a result from the cone segment being approximately a small segment of a hemisphere. (Picture a series of small segments with progressive angle of taper to form a hemisphere). Their website has product info and more, www.taper-lok.com .
I have not used the taper-lok flanges. The flange joint is rigid after bolts are torqued, so no flexibility is gained for thermal expansion of the piping. Techniques to improve fit up of the piping could be 1) Starting at the equipment connection run piping outward and adjust supports to keep weight off equipment and make final field weld at points away from equipment. 2) If piping is run to equipment connection, then the final spool must be field fit & welded, not just a pre-fab shop spool. 3) Field heat treat of the final spool in position can relieve the stresses of mis-alignment, reducing the installed loads.