The Craftmans Shop > New from Old
Resurrection of a CFEI 100 KVA Induction Furnace
Spurry:
It seems, at times, that we are much kinder to animals than humans.
On the proper topic, what about say 3 olives spaced out and soldered onto the stub?
awemawson:
Thanks chaps for your kind comments re: Hugo
Possible pipe blockage discounted - coil uncoupled and 'blown through'
Yes I was thinking perhaps an 'olive' or two soldered to the stub of pipe would be effective. I've been trying to find photos (from when I grouted in a replacement crucible) of the 'other end' of the flexible pipes to see if the native stubs on the coil are barbed or not but have drawn a blank. I have a spare coil assembly - I'll dig it out and see what it has.
A quick calculation knowing the system pressure is 50 psi and the pipe about 1/2" gives a 'pushing off' force of just under 10 lbs so not enormous, but as Graham said the pipes warm up.
As the stubs are just into a compression fitting I may just turn up some barbs anyway.
I noticed a few weeks ago that the coolant was far from clear - with a brownish tinge - I cannot remember whether it was tap water (probably) or demineralised water with a good dose of ethylene glycol as an antifreeze. Googling induction furnce coolants there are dire warnings not to use automotive antifreezes which I'd intended to use for it's corrosion inhibiting properties. The brown tinge I think can only be iron salts (*), and the walls of the holding tank have a thin brown slime layer that probably is the same. As far as I can tell the majority of the water passages are copper, a bit of brass in places, and a small amount of cast iron in the housing of the circulating pump. Borax has been suggested but I'm loathe to start making up my own concoctions.
Certainly a major clean out and flushing is called for before melting restarts. And the antifreeze will need replacing.
(* when I noticed the brown tinge I thought it might have been coming from the bore hole water, which IS iron laiden but the plate heat exchanger isolates this from the circulating coolant)
awemawson:
A quick foray into the Tractor Shed reveals that the spare coil has indeed got 'olives' soldered on the ends of its centre tap pipes.
Now this coil is not identical to the one currently fitted but was made by the same manufacturer, so it's probable that this is how the 'other end' is terminated.
awemawson:
First job this morning - remove the 15 mm copper stubs that introduce the coolant to the coil assembly and sweat on olives to give better retention (hopefully).
(Slightly delayed by having to re-wire the cleaners hoover cable YET AGAIN - traded for cleaning the loo in the workshop !)
Olives fitted, stubs refitted, pipe re-installed and the back of the furnace body given a good blow out with dry compressed air so that any leaks during testing would be more easily detected.
Fingers in my ears I started the Grundfos circulating pump. Tank level is very low as most coolant had previously ended up on the floor but is high enough to feed the pump. Pressure rose to the set point (50 PSI) and there were no dramas of pipes popping off thankfully. Both magnetic flow sensor 'torpedoes' were in their raised position indicating that both coolant circuit have flow. I left it running for a few minutes and no apparent leaks - tank was frothing due to the low level making the return pipe above the water level.
So I need to let it all thoroughly dry out, flush out and clean the coolant circuits and replace the coolant. I have 50 litres of Mono-Ethylene-Glycol on order and also 50 litres of demineralised water all of which should arrive early next week.
Pete.:
Sorry to hear about Hugo Andrew. You've only the puppy left now?
I hope he's as comfortble with my Rosie as your other two were. They were both lovely characters.
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