Lens Ring Flanges

[CSGWB]

Could anyone point me in the right direction for the application of gasket forces on a high pressure Weld neck style flange with lens ring gaskets. I need to perform flange calcs to ASME VIII for the flanges and want to make sure the effects of the shape of the gasket face are taken into account.

Thanks

 

[SnTMan]

Lens ring = ring type joint?

 

[vesselfab]

is he talking about sight glasses?

 

[jamesl]

He was talking a special RTJ type of gasket. There is an industrial standard MSS-65 for flanges that use this kind of gaskets.

 

[SnTMan]

http://www.smithgaskets.com/rtj-lens.php

Should be able to use factors from Apx 2, Table 2.5.1, looks to me like.

Regards,

Mike

 

[fegenbush]

I suppose this goes to show that you learn something new every day. I was not aware of the existence of this type of flange/gasket before.

Thanks for the reference SnTMan.

 

[Duwe6]

"Check out Taper-Lok high pressure compact flanges:

http://www.taper-lok.com/

And, how about this big sub-sea check valve and more? :

http://www.taper-lok.com/taperlokprojects.htm

In my former employ, we used Taper-Lok for some designs in approx. 7500 psi range. But wait. I am not a flange guru either.

We previously used lens-ring construction that was designed originally in 1950's by machine design engineers. All of those connectors are with threaded flanges, having straight threads. Gaskets are rings made from pipe material and make their seal against pipe ends. Each gasket and pipe end has a slightly different contour so there is a fine line of contact at assembly. Fittings are machined studded blocks of steel or stainless steel.

Some leakages occurred during shutdown and restart where lens-rings were used. This prompted us to look for a potentially better joint, and Taper-Lok proved to meet our needs. The Taper-Lok design also requires studded block tee and multi-port fittings.

There is an MSS document that now covers lens-ring:

http://www.mss-hq.com/price_list.htm

MSS-65-1999, "High Pressure Chemical Industry Flanges and Threaded Stubs for Use with Lens Gaskets," $60.00 US. It includes weld neck style and threaded.

Ben "

Found this by Googling MSS-65. Taper-Lok is MUCH better.

 

[SnTMan]

fegenbush, you're welcome, of course. That was the result of a fairly brief search.

No doubt there is more art to it than just gasket factors

Regards,

Mike

 

[vesselfab]

Well ain't that neat. Never seen them before.

 

[jamesl]

CSGWB,

I don't know if you have access to Maan Jawad and James Farr's book "structural analysis and design of process equipment". It has the info of lens gasket. I think that is all you need to finish flange calc.