Cast Iron to Steel
Posted: Sun Jun 10, 2018 11:24 pm
A lobe type oil charging pump I fitted up for a refrigeration plant to top up compressors came back for repair - locked up, only a few months old.
Turns out the customer was sneaky draining old oil out of the accumulators (pressure vessels) and pouring it into the new oil drums and pumping it back into the compressors to save some bux. Lobe pumps don't like gritty old oil. So I decided we need a fine strainer. Customer has one - please use it. No flanges, none in the country anymore in a male/female set (the danish are turning cheepskates expecting contractors to hold their stocks for them). Does this happen elsewhere or just OZ (the backside of the world)?
So I decide to weld steel screwed sockets onto the cast iron body. I have some EZ Weld Tig Rods which I thought to give a go.
Ground the strainers connections flat with a flapper disc. Cleaned up the sockets (1"). DCEN, argon, 150amps on the peddle but used probably only 100amps. The cast iron spat and sparkled a bit, no pre-heat as recommended. The run went in somewhat OK, heard no chinking but was only game to put one pass in. Not going into pressure service so that does not matter. Not the prettiest weld but it holds hard and does not leak so all good. Here's some pics.
Turns out the customer was sneaky draining old oil out of the accumulators (pressure vessels) and pouring it into the new oil drums and pumping it back into the compressors to save some bux. Lobe pumps don't like gritty old oil. So I decided we need a fine strainer. Customer has one - please use it. No flanges, none in the country anymore in a male/female set (the danish are turning cheepskates expecting contractors to hold their stocks for them). Does this happen elsewhere or just OZ (the backside of the world)?
So I decide to weld steel screwed sockets onto the cast iron body. I have some EZ Weld Tig Rods which I thought to give a go.
Ground the strainers connections flat with a flapper disc. Cleaned up the sockets (1"). DCEN, argon, 150amps on the peddle but used probably only 100amps. The cast iron spat and sparkled a bit, no pre-heat as recommended. The run went in somewhat OK, heard no chinking but was only game to put one pass in. Not going into pressure service so that does not matter. Not the prettiest weld but it holds hard and does not leak so all good. Here's some pics.
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