Pressure vessel repairs
Pressure vessel repairs
(OP)
I have a small (3m^3), low pressure (8kPa) vessel that is badly corroded. In the past when vessels have corroded through (pin holed), we have been able to weld a socket over the pin hole and seal it that way. In this current situation, the wall thickness is too thin (below 3mm from a design of 4.5), so this option is not viable.
Has anyone heard of any coatings you can apply to this vessel (when offline) to stop any leaks?
The vessel cannot be taken out of service for more than a couple of hours in the next 6 months, hence the need for the interim repair.
Any other thoughts on a repair method?
Has anyone heard of any coatings you can apply to this vessel (when offline) to stop any leaks?
The vessel cannot be taken out of service for more than a couple of hours in the next 6 months, hence the need for the interim repair.
Any other thoughts on a repair method?





RE: Pressure vessel repairs
People routinely line tank floors with heavy fiberglass coatings. While these would do the job in your case, they would normally be applied from the inside, and would take some time to cure.
I've repaired a pit through an aluminum gas tank on a lawnmower with 5-minute epoxy, and that held for several years (still is holding, in fact).
They do make 100% solids epoxies that can be applied under water. Not sure what chemicals they are resistant to, and how well they would work applied from the outside over a hole. Aquatapoxy is the brand I've heard.
Be cautious even with the low pressure. If it comes apart, it could still get exciting.
RE: Pressure vessel repairs
I presume you've considered global structural strength issues (don't want the vessel to collapse under its own weight!) and simply need something for pressure containment for six months. I agree that at 3 mm the wall just isn't likely to be thick enough to weld to.
Something we'd consider for a (non-Code) drum repair would be a steel patch installed with an adhesive. If you can get to the inside of the drum, that would clearly be the best side to install the patch, but we've done water tanks from the outside with good success. Talk to a representative from http://www.belzona.com for adhesive selection. They'll probably tell you that you won't need the steel. I guess we're just not quite ready to rely solely on the Belzona product and our folks (myself included) are just happier seeing a steel patch.
Other options you can consider if the diameter is small enough would be http://www.clockspring.com, http://www.flowserve.com/srvnrepair/power_patch.as..., and http://www.airlog.com/page3.html.
Let us know what approach you choose and how it performed. Good luck!
jt
RE: Pressure vessel repairs
RE: Pressure vessel repairs