COOLING TOWER

1. Turn off Caps Lock
2. Apply submersible silicone sealant, preferably to the inside surfaces.

Check for what additives you are putting in the cooling tower to control corrosion or Legionella. Check for compatability with SS. Check for possibility of Stress Corrosion cracking.

If all comes out good, check for vibration and fatigue failure. If vibration leading to fatique failure comes out to be the issue then find a way to strengthen the failure area by use of stiffeners.

If the leak is from the expansion joints on the civil works, then use Combiflex on the joints.

To contain the leak in the first pass, use temporary measures such as sealants suggested by PWSlack.

I am sure if you follow the suggested approach, you should solve the problem.

i have used araldite successfully you need to empty the cooling tower and dry the area you need to seal clean the area that has to be sealed with fine sandpaper throughly mix the araldite compound till you get dirty smell from the mixture and the mixture becomes slightly hot due to chemical reaction of two components of araldite. and apply the mix on the seams with a clean stainless steel thin rod or wire allow to dry, on board submarines i have used this to seal leaks on engine exhaust lines ,cooling water lines and even high pressure compressed air lines subject to pressures of 10Kg/sq cm and temperatures of 400-500 degree C the araldite holds up to six months to a year when you take a long shutdown you can go permanent stainless steel weld of the seams.good luck

crm

Sounds good, but Araldite makes lots of adhesives. Which one did you use?

we were using general industrial grade two component (hardner and resien)

crm

Before any repairs are made, you should do NDT to determind the cause and extent of the problem.

After NDT evaluation, you will be able to make a proper course of action. Weld repair, sealant, or replacement.

How large are your cells? If your tank is large, you must do an evaluation. Large tanks can fail in a catastrophic moment causing death and destruction.

You can use M seal manufacture by Pidilite in India in operation of cooling tower, and weld it when ever you get a shut down.

Have you contacted the equipment manufacturer?

They are your best source for a problem such as the one that you are having.

Look at the equipment manual or reference material and you might find the answer.

I would be willing to bet a sizable chunk of money that the root cause of the failure is going to be sensitization of the HAZ during welding caused by too much heat input during welding to achieve good puddle flow. Welding Stainless Steel is appreciably different from welding carbon steel and it is a common mistake of inexperienced/uneducated welders to crank up the power to get the puddle to flow out well. Too much heat in the HAZ will lead to chromium carbides forming in the HAZ. This will tie up the chromium and prevent it from serving to make the chromium oxide protective layer. You'll end up with a corrosion seam in the HAZ every time. Molten Stainless is viscous and does not flow well and it leaves an ugly bead. Welders HATE that and they strive to make the bead look pretty. That takes additional heat. The use of low carbon stainlesses (304L or 316L for instance) for weldments help, but do not eliminate this problem. Low carbon stainlesses are also lower strength than their higher carbon bretheren so designers will sometimes use them anyway, or purchasing people will substitute it not knowing the difference.

Welders in training are repeatedly cautioned to use the absolute minimum power and shortest dwell time possible with Austentic Stainlesses, and almost universally the less experienced ones disregard this advice.

This article covers the metallurgical issues with sensitization of Austentic Stainlesses.

http://www.msm.cam.ac.uk/phase-trans/2005/Stainless_steels/stainless.html

You can try to grind the HAZ out and re-weld but you will have to make sure you grind the HAZ out completely, which means that the weld will be that much larger (and hotter). If this is your chosen repair, use alloy 347 filler wire. It is stabilized with niobium (columbium for you old timers out there) and will help to tie up the carbon preferentially leaving the chromium to do it's job of preventing corrosion.

Go to this website. http://www.belzonamolecular.com/ Ask them how to contact your local representative. Follow their instructions exactly.

One other thing to consider. if you use an epoxy type repair, you will probably have a problem with pitting corrosion along the edge of the repair, especially if chlorine is your disinfectant of choice.

Welding.