The Craftmans Shop > New from Old
Resurrection of a CFEI 100 KVA Induction Furnace
awemawson:
Not seen it yet, but a friend (at my prompting) reckons he's found an odd length of cement reinforced downpipe approximatly 4" O/D, and my calculations indicate that if I mount this horizontally on the 'casting body' frame the Brewers Hose cables can rest on it keeping them off the air lines.
All theory at the moment - I did find a bit of 5" i/d 5.5" o/d flue pipe but it's a bit too large and kinks the pipes.
awemawson:
Today was the first opportunity to do a 'full power' test on the new breaker arrangement. Cottage guests were out so I could run the generator, and it was no longer freezing so I could return the bore hole pump to service.
So turning on the bore hole pump I opened the ball valve allowing water the flow through the heat exchanger to be presented with a blast of high pressure water all over the place - more frost damage on the far side of the ball valve so at least 'turn offable' !
OK it needs repairing but press on - the water chiller has a few gallons in the tank of glycol dosed water that it circulates through the furnace, so it can run for a short while without the heat exchanger.
I ran the furnace up to about 60 kW and all went well just heating a bit of 20 mm re-bar to glowing but then stopped before things over heat without the bore hole water,
Digging through pictures that I took installing the plumbing that's sprung a leak it's not the easiest to get at but possible - so that's my next task in the next few days - and perhaps extend my frost trace heating system.
awemawson:
Frost prevention measures:
My first thought had been the wrap snti-frost tape round the two umbilical hoses that join the water chiller to the flow and return mainifold to the bore hole.
Now tape isn't particulary convenient on flexible pipe but it can be done.
Then I thought: the return pipe is open at the well end - can I adjust the piping so that opening a ball valve it all flows out. But no, the height of the manifold compared to the heat exchanger prevents this.
My current thought is, if when I make good the frost damage on the flow pipe I incorporate an air input valve, when cold temperatures threaten I can maybe blow the water from both the flow, return and heat exchanger back down the return pipe (thus overcoming gravity) leaving hopefully minimal water in the system.
Any other suggestions would be very welcome.
awemawson:
Today I stripped down the water feed and return pipes from the Borehole to let me take the panel off the wall in the foundry and investigate what actually has burst.
To my surprise I've found that the actual body of the ball valve has split - it's a dead ball valve :bugeye:
So having ordered up a replacement I've also decided on a 'frost strategy' for the future. The pipe rises from the ball valve and goes through 90 degrees to a convenient place on the panel. I will replace the 90 degree 1" BSP elbow with a Tee - and the extra 'way' will be reduced to 1/4" BSP, have a 1/4" Ball Valve followed by a 'Male PCL' air fitting.
This scheme should allow me to 'blow down' water from the pipe work and the side of the heat exchanger that isn't antifreeze filled.
As an extra line of defence I've also ordered decent quality pipe lagging and am off now to hunt for a suitable length of frost stop heat trace cable.
awemawson:
Glad to say UPS delivered my B.E.S. plumbing order nice and early so I was able to get on with putting it all back together.
A bit of heat released the Loctite holding the 1" BSP elbow to the various other fittings and having replaced the elbow with a Tee, the ballcock with one without a burst bit, and installed the 1/4" BSP air ball cock and PCL fitting I was able to put it all back on the wall. I took great care to mark the blue MDPE pipes for insertion depth and seat them firmly as both have to go on as an assembly - if I've got it right it wont leak . . time only will tell !
Then I removed the old nylon reinforced umbilical pipes that take the feed from the borehole to the heat exchanger, and the return that goes eventually to the stream via our land drains. I had bought some much more substantial stainless steel wire reinforced rubber 'Neptune' hose quite a long time ago as the nylon was a temporary solution - it had worked OK but wouldn't take kindly to a splash of molten metal. So now was the time to uses it.
All went well and I'm now waiting a few hours for the Loctite 542 to cure before I pressurise and test it.
The split / self fixing 1/2" wall insulation for these pipes has also arrived but the trace heating cable hasn't so I can't wrap up the umbilicals just yet. It's going to be great fun installing the trace heating. I've ordered a single 14 metre length the mains 'start of which will begin at the wall panel, wrap in a spiral round the return pipe, enter the chassis of the chiller wrapping round its internal pipes and exit wrapping around the flow pipe ending back at the panel. Or that's the theory - I can imagine quite a tangle during the wrapping !
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