Author Topic: Resurrection of a CFEI 100 KVA Induction Furnace  (Read 83295 times)

Online awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #700 on: February 06, 2021, 10:48:15 AM »
Various bits of plumbing arrived this morning allowing me to connect the Ceramic Chip Forge to propane. The 8 mm flexible gas pipe had perished, and goodness knows what happened to the female quick disconnect wall fitting so this is what I had had to order.

The gas cylinder is one I brought from Bromley 13 years ago and still has a little left - it's a 47 kg cylinder (tare 40 kg) and my bathroom scales say it now weighs 56 kg so 16 kg of gas left.

Finally the cylinder will be permanently fitted in the Cylinder Cage that I made last year, but to avoid drilling holes in the wall just for a test I brought it into the foundry.

To my amazement all seems to work, but I need to find out some how what delivery pressure it expects. It has a pilot light like a bunsen burner on the end of a pipe, a blown air / gas torch on pipes that are far too stiff for comfort, and of course the forge itself which is rated at 22 kW.

It lit up OK and I tweaked the gas pressure to a flame that looked reasonable and let it cook. Ten or fifteen minutes later I had some 1/2" bar glowing at a nice forging temperature  :ddb:

So it just needs a permanent site and fixed plumbing, though I am very tempted to leave it on it's wheeled skid for flexibility.

Andrew Mawson
East Sussex

Online awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #701 on: February 06, 2021, 11:00:45 AM »
Well it helps to read the rating plate - 20 mBar !

It is marked for 'natural gas' ie North Sea Gas but I can't remember if it had been converted to propane or if I found it satifactory without conversion. BUT I did find a record of correspondence that I'd had with another shed dweller describing the difference in size of the jets so I must measure them at some time.
Andrew Mawson
East Sussex

Offline hermetic

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #702 on: February 06, 2021, 02:26:12 PM »
www.flamefast.co.uk, theyre still in business, and apparently expanding! That forge looks very good, and fast......and smokeless! Lucky man!
Phil
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Offline tom osselton

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #703 on: February 06, 2021, 07:52:18 PM »
I’ve got this chart if it’s any use to you.


Offline russ57

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #704 on: February 06, 2021, 11:29:41 PM »
Never seen such a thing.
Propane forges are very handy, but often challenging to fit anything other than straight bar.
How hot can it get?

-russ


Online awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #705 on: February 07, 2021, 02:19:56 AM »
Years ago as an experiment I did some hammer welding of some bar like that illustrated glowing above, and it was hot enough!

Leave a bar too long in and you can suffer the indignity of melting the end off !
Andrew Mawson
East Sussex

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #706 on: February 07, 2021, 04:42:25 AM »
Time to investigate the Flamefast DS130 Main Jet:

It nestles behind a 1/2" BSP plug blanking off one branch of a Tee fitting, and the jet is long enough to project into the Venturi chamber allowing the passing forced air to draw gas through the jet and from the 'Zero Pressure' valve. I don't think I've had this out before as it wasn't familiar as I dismantled it.

Anyway, using drill shanks as precision measuring tools (!) it measures as 4.1 mm - this doesn't correspond to either of the two possible sizes cited by the late Tim Leech in the document I posted above where he says #28 (3.56 mm) for Propane and #17 (4.39 mm) for Natural Gas

. . .odd  :scratch:
Andrew Mawson
East Sussex

Offline russ57

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #707 on: February 07, 2021, 05:30:45 AM »
Half way in between..
Sounds like a 'universal' option..

-russ


Online awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #708 on: February 07, 2021, 05:50:02 AM »
Funnily I just voiced that possibility to the wife  :clap:

I can't think Flamefast would have sold it with a universal jet and still labelled it for Natural Gas, probably more likely some one has modified it over the years, after all it's 38 years since it was made - lot's of time for fiddling by someone trying to get more oomph out of it!

Frankly as long as the flame is OK I don't suppose it matters much - I need to investigate the torch and bunsen pilot light though as they are quite fierce.

The other variable is supplied gas pressure - I'm just setting the regulator on the cylinder to a low PSI, the label says 20 mBar which is 0.3 PSI, BUT all gas supplied goes directly to one big internal regulator which I haven't tweaked so presumably it's set as per Flamefast intended.

There are test nipples on both the inlet and outlet sides of this main internal regulator and I do have a suitable gas rated manometer (from when I did a CORGI course years ago) so as long as it's rubber tube hasn't perished too much I can measure it, but not knowing what pressure the internal gas plumbing is supposed to be anyway I haven't bothered.

. . . life is full of conundrums  :med:
Andrew Mawson
East Sussex

Offline Pete.

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #709 on: February 07, 2021, 06:25:54 AM »
Does the jet size and pressure affect the flame properties in the same way as an oxidising/reducing flame from a gas welding torch or is it just a matter of efficiency?

Online awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #710 on: February 07, 2021, 07:29:31 AM »
Effectively yes Pete, you need the right raito not to get a sooty flame and get a hot enough flame.

These things never go smoothly do they - I just came out to the workshop to try and free up the volume control on the gas torch - just a simple taper duel gas cock - dismantle, clean, grease, put it back together and test. Simple, except when I came to test, the gas interlock valve won't operate - no gas - no flame  :bang:

Now the two valves, the interlock, and the zero pressure are made as a single diecast  block with two coils removable to operate them. This unit gave me trouble years ago, and I sourced a new valve block, but it turned out just one coil had failed. So I have a block with just one coil. Wiring the spare coil to a mains lead and with everything else turned off I was able to prove that the lower valve unit wasn't operating. Nice click from the upper one, just humming from the lower with the same coil used each time, so the lower valve is  stuck in the closed position. Gentle tapping and warming have failed to free it so it looks like I'm going to have to fit the spare I bought all those years ago.

The plumbing isn't conducive to removing it as various elements haven't room to rotate due to the outer cover. One pipe has a knuckle joint so easy to remove, but the other doesn't !

- lunch time. I'll have a go after lunch.

Andrew Mawson
East Sussex

Offline AdeV

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #711 on: February 07, 2021, 07:30:08 AM »
What's the jet size for Butane? Would that be somewhere between propane & NG?
Cheers!
Ade.
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Location: Wallasey, Merseyside. A long way from anywhere.
Occasionally: Zhengzhou, China. An even longer way from anywhere...

Online awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #712 on: February 07, 2021, 09:18:25 AM »
Interesting point Ade - I don't know  :scratch:

So pulling the front casing off I was hoping to reveal a union to allow me to pull the pair of valves out in a civilised way, but sadly none were apparent. so I am going to revert to drastic measures and saw off the pipework, and when I re-make it insert a standard pipe union where the stubs of the cut off pipe will be.

1/2" BSP pipe union ordered - should be here Tuesday meanwhile I'll get on sawing off the pipe. No doubt filings will fall into the valve but it's being replaced anyway so hey - ho !

Andrew Mawson
East Sussex

Offline hermetic

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #713 on: February 07, 2021, 09:48:46 AM »
Beware Andrew, when I first fired up my Flamefast brazing hearth using a variable blowlamp regulator, I got a roaring blue flame, and lots of heat, but after a few minutes my CO alarm went off, warning me of incoplete combustion and potential death! I got the right regulator as recomended by Flamefast, and it made a huge difference! Drop them an email, their tech dept are very helpfull
Phil
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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #714 on: February 07, 2021, 10:16:45 AM »
Good point Phil, although this is the same regulator that I used for years before I moved - googling tells me no more than 35 mBar at the input to the forge regulator for Propane, and it seems that my manometer tubing IS still OK. I'll check it's set up when I replace the gubbins that I've just sawn off. Mind you, incomplete combustion should have given you a yellow flame (carbon particles in the flame) not a blue one.

I've just taken the reciprocating saw (newly acquired - thanks Steve !) to the pipe work and sliced off the offending bit that I couldn't unscrew.

Now remember I tapped, nay even BASHED the unit while I was testing it hoping to free it up into a working state - now needless to say having used the reciprocating saw on it's pipe guess what - it works ! I'm not entirely surprised.

So I think I will put the original back, but it will have to have the union fitting of course, as if it sticks again it will only be a union and a pipe clip to remove it for replacement.

Andrew Mawson
East Sussex

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #715 on: February 07, 2021, 12:02:27 PM »
Following Phil's regulator comment I've been doing a bit of 'internet research' this afternoon.

Firstly, the forge is rated at 22 kW which is equivalent to 1.6 kg/H of propane - many regulators are marginal being rated for 1.5 kg/H and some only 1.0 kg/H.

Secondly most propane appliances expect 37 mBar input pressure so it's reasonable that this the forge when converted would be the same.

I have no idea of the rating of my regulator, but if it and it's pipework (8 mm) are not capable  of maintaining 37 mBar at the forge input I'll replace it.

If the regulator isn't 'up to snuff' to supply enough throughput the output pressure will fall with demand, and owing to the way the forge works drawing gas by an air operated venturi the gas / air mix will be too weak, so combustion should be complete anyway.

Internally the propane is further regulated down, and while this second regulator is on the bench I'll see if I can measure its output pressure.

 . . .now to seek out a drop of dye or proper ink to colour the water in my Monument water gauge so I can see the level!

Andrew Mawson
East Sussex

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #716 on: February 07, 2021, 03:14:17 PM »
Re the yellow flame Andrew, yes, that is what I would expect, but my hearth has a 4psi air blast and although it produced a blue flame, it seems there is a cold centre to the flame, as if the gas is fed to the nozzle round the outside, and the air in the centre. If you look at the nozzle, this seems to be the case.. It was fairly belching out CO, and only took a few minutes to set the detector off, whereas now, with a 37mbar regulator the flame is much hotter, and no CO is detected! It had me scratching my head because as you say, it doesnt make a lot of sense, but it seems to work very well now.
Phil.
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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #717 on: February 07, 2021, 03:33:48 PM »
Phil can you confirm that your new regulator is definitely a 37mBar one? Have you any idea of it’s rated through put in kg/H and what does the rating plate of the hearth say about heat output in kW ?

You’ll be pleased to hear that I’ve ordered a couple of CO monitor / alarms !
Andrew Mawson
East Sussex

Offline hermetic

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #718 on: February 08, 2021, 09:39:22 AM »
Its this one Andrew
https://www.ebay.co.uk/itm/IGT-37mbar-PROPANE-GAS-REGULATOR-WITH-PRESSURE-GAUGE-2-M-HOSE-KIT-WITH-2-CLIPS/163753022109?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649. All the other information is at the workshop and we are having a snow day today, so I will get it as soon as I am back there. The torch on my hearth is a flamefast T4.
Phil
Man who says it cannot be done should not disturb man doing it! https://www.youtube.com/user/philhermetic/videos?

Online awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #719 on: February 08, 2021, 09:43:31 AM »
Well, developments of sorts. I spoke to Flamefast in Warrington, and it turns out that the 'regulator' that all the input gass passes through is not a regulator but a non return valve. This would explain why when I tried to measure it's output pressure having made a 'mock nozzle' of the same 4.1 mm diameter as is currently fitted I got the same pressure in input and output! Apparently all the internals when on propane are supposed to run at 37 mBar.

In the absence of ink I used some red food colouring dye in my water manometer to make the level easier to see, but being intended for natural gas it only goes up to 30 mBar !
Andrew Mawson
East Sussex

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #720 on: February 09, 2021, 07:17:30 AM »
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.
« Last Edit: February 09, 2021, 07:58:30 AM by awemawson »
Andrew Mawson
East Sussex

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #721 on: February 10, 2021, 10:11:13 AM »
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.

Andrew Mawson
East Sussex

Offline vtsteam

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #722 on: February 10, 2021, 11:12:17 AM »
Andrew does your old jet have a taper on the inside towards the orifice end?
I love it when a Plan B comes together!
Steve
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Online awemawson

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #723 on: February 10, 2021, 11:46:00 AM »
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
Andrew Mawson
East Sussex

Offline hermetic

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Re: Resurrection of a CFEI 100 KVA Induction Furnace
« Reply #724 on: February 10, 2021, 12:27:29 PM »
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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