The Craftmans Shop > New from Old
Resurrection of a CFEI 100 KVA Induction Furnace
awemawson:
My 1/2" BSP taper union arrived this morning so first job was to work out how much longer the union with it's stubs of pipe will be compared to the length of pipe that I cut out.
Answer = 20 mm - now this means that the dual valve unit and non return valve will sit 20 mm lower in the machine, but they are supported on a saddle clamp that needs lowering by the same 20 mm.
Easy - its a 'kit of parts' with the lower fixing being tapped 1/4 BSP as is the lower half of the saddle, and they are joined with a bit of 1/4" BSP pipe. Pipe needs cutting shorter by 20 mm and threading. In practice I did the threading first to use the existing thread as a 'starter' for hand threading.
All went well. Gas joint threads sealed with Loctite 542 and it fitted nicely. Once the Loctite had 'gone off' it was time to test it.
Did it work . . . NO :bang: The solenoid valve had jammed again. Never mind it's now SO easy to remove, just undo the union, release the saddle clamp and out the assembly comes.
So I test it on the bench with every intention of putting in the new one BUT the bally thing works perfectly. so for now I've re-installed the assembly, gassed it up and proved that it works. If it sticks again I'll swap it out for the new one.
Still no word from Flamefast as to what the correct jet diameter is but I've done a sketch of the jet so that I can make one to size without further dismantling. It's a bit of 1/2" brass bar tapped M12 at the business end where the jet hole is, and drilled 8 mm down the rest of it's length. I'm out of stock of 1/2" brass bar but I do have 1/2" hex which will fit so that's what I'll use when I know for certain the right size.
awemawson:
Still no word from Flamefast despite another nudge so I thought that I may as well just go ahead and make a new main jet from the data I got second hand back in 2004. It calls for a #28 drill which I don't have so I erred on the next size down in my tenths metric set at 3.5 mm. Better too small as I can always open it up.
Easy enough bit of turning, and it fits nicely and works. Output of the hearth at the same pressure is naturally a bit less than before as you would expect. I have a tweakable regulator fitted at the moment but have a proper 37 mBar pre-set high capacity one on order.
Phil I didn't order the one you linked to - enlarging the picture it is rated at 1.5 kg/H - this hearth takes 1.6 kg/H so close but too marginal - the one I have on order is 4 kg/H rated so comfortably in spec.
vtsteam:
Andrew does your old jet have a taper on the inside towards the orifice end?
awemawson:
Not discernibly Steve, it steps from 8 mm (65 mm deep) down to jet size (was 4.1 mm now 3.5 mm) jet bore being 25 mm deep.
The thread strangely is M12, I'd have expected it to be BSP of some size, so I have a feeling things have been re-engineered previously
hermetic:
Interesting Andrew, I will have to check the spec on my torch, I may have a slightly too small throughput!
Phil
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