Clamp shell bellows for quick sealing welding

[0707]

Expansion joints are critical equipments in a FCC flue gas piping system. I am looking for any information on the use of outer pre installed clamp shells on new expansion joints. The intention of the outer clamp shell is for quick sealing weld, just in case of a flue gas leak through the inner expansion joint, avoid a big shutdown and keeping the unit running till the next big turnaround for definitive replacement of the inner expansion joint.


luis marques

 

[ApC2Kp]

luis,

The clamshell bellows were offered as a quick repair service by Pathways Bellows. After being acquired by Senior Flexonics, don't know where that technology ended up. Any repair welding on operating unit requires a shutdown. You may have thought of having the clamshell bellows installed at same time as the primary bellows for the clamshell piece to act as a containment for possible leak. There multiple ply bellows that would provide backup in event of leak thru the first layer of bellows. Pressure tap to the space between plies would give signal of leak.
websites to try, among others.

http://www.seniorflexonics.com

http://www.oakridgebellows.com

http://www.pipetech.com

http://www.stejasausa.com

 

[0707]

ApC2Kp

Thank you for your reply. The intention of my posting is to share points of views with others experience on dealing with expansion joint bellows in FCCU units. As you know, expansion joints are critical equipments in FCCU complex flue gas piping systems. The most critical are the ones installed in horizontal position, as the acid flue gas condensate tends to accumulate in lower point of bellows, accelerating the corrosion.
Nowadays, FCCU units are required to support cycle runs of 5 years, for this reason, expansion joints should have great liability and in that sense the actual tendency is to use 2 ply expansion joints with pressure taps to signal leakage of inner ply. Any way, besides the liability improvement with the use of 2 ply bellows, my intention is to have a redundant protection in the case of failure of inner and outer plies.
I think that it would be possible to equip expansion joints with redundant devices such as flexible telescopic boxes around the bellows plies, with stuffing box and solid ring with screw fasteners to push the stuff and stanch the leak when it occurs.
Such a system wouldn’t require any welding. To stanch a leak we only need to slow down the unit until zero pressure, to allow maintenance workers to fast the screw fasteners.

Others input on this discussion is welcomed

Regards

Luis marques