Using a welder to thaw ice in a conduit was somehting that I've read about but never acutally done. Today I had a chance to do it.
The conduits are 3/4" GRC buried in the slab of an Anhydrous Ammonia tank. The conduits carry heat trace lines that are supposed to keep the ground from heaving and destroying the slab. The job was to replace a majority of the heat trace.
Almost all of the conduits were plugged with ice. The Anhydrous stays at -20°F so even during warm weather the slab is frozen.
We attached the welder at each side of the tank and ran 400A through the conduit for about 20 minutes. That would loosen up the ice enough that we could pull out the old trace.
Also learned today that an engine driven scroll compressor will pump enough air at 100psi that you can blow heat trace out of a conduit. Make sure no one is in front of the gun barrel!
GJ
