Flange studs or bolts for lugged valves 1

[KevinNZ]

Can flange studs be used for threaded lugged butterfly valves? The studs would be treaded in from each side. Is there reason this would not work?

Our project uses studs every other flange connection.

thanks

 

[TugboatEng]

The benefit of lugged valves is that they allow the downstream piping to be removed while the valve is in service. The best way to do this is with a threaded rod and nuts on both sides. If pressure is low you can also use a short bolt/stud on each side (very common in the marine industry but I'm not a fan). The third option is to use a fully threaded bolt all of the way through with a nut on the opposite side but this doesn't allow removal of the downstream piping.

 

[bcd]

To install lug body butterfly valves, safest and best way is to use studs and nuts. Studs ensure you get the maximum possible thread engagement. The length tolerance on machine bolts can lead to low thread engagement which can lead to stripped threads in the body when bolt is exuberantly tightened. Or, just as bad, can lead to bottoming out in the hole preventing full compression of the gasket. Always go with studs and nuts.

 

[KevinNZ]

Thanks for replies.
Another tip is, have the studs long enough to fit a second nut for removing the studs from the valve body.