Swivel Type Flange (Collar) Nuts

[ValveEngineer123]

Does anyone know if collar nuts with a swivel washer are acceptable to use for B16.5 flange bolting applications?

I have an application where a blind flange is bolted on and off a mating flange several times per day and the blind flange is starting to wear at the nut bearing surface. I want to use swivel nuts to reduce the wear on the blind flange, however B16.5 recommends the use of B18.2.2 for determining dimensional requirements for nuts. Collar nuts aren't specifically dealt with in B18.2.2, nor are they specifically disallowed. Does anyone have any thoughts as to why a swivel nut wouldn't be allowed?

 

[unclesyd]

Why not use a hardened parrlell face flat washer under the nut

The Swivel Nut doesn't meet any bolting standards. As the Swivel NUt asembly could allow some angularity in the bolted assembly it presents an intgrity problem.

http://www.boltscience.com/pages/nutfaceangularity.htm

 

[JohnBreen]

You might want to read these NBIC Technical Articles on Quick Opening Closures:

http://www.nationalboard.org/Index.aspx?pageID=205

http://www.nationalboard.org/Index.aspx?pageID=197

Regards, Jogn