Swing Bolt Torque Calculation for Pressure Vessels with 0-ring Closures

[Darrell.K]

Wondering if anyone can help with the following,


Is there a straightforward method to determine the required torque values for Swing bolts on a filter vessel lid in the absence of any supporting documentation? The only available information is that the vessel has a diameter of 18 inches and a maximum working pressure (MWP) of 100 bar.

TIA!

 

[gb2835]

You may want to find a copy of ASME BPVC VIII-1. Appendix 2 is titled "Rules for Bolted Flange Connections with Ring Type Gaskets." Perhaps this is the type of application for your lid. Below is a screen shot of part of the Appendix. PLEASE keep in mind that bolted joint torque calculations can be tricky (see below from Fastenal). This is due to it being difficult to get a solid number for the friction on the threads. A dry bolt will take more torque than a lubricated bolt to get the same preload. You can find calculators online that take approximately things like this into account, but still be cautious when dealing with pressure vessels. There is an old paper titled "Analysis and Design of Threaded Assemblies" by Harris where a lot of the online calculators are based on.

 

[Compositepro]

It is possible for "finger tight" to be sufficient. O-rings are pressure energized, and bolt force is only required to get an initial seal. Pressure will only make the seal tighter

 

[gb2835]

+1 to the above. I missed the o-ring mention in the title.