Resurrection of a CFEI 100 KVA Induction Furnace

[awemawson]

Today's tasks - start putting it back together, and try and make a start on mounting the electrical isolator switch that prevents opening the enclosure door when 'on'.

Re-assembly was fairly straight forwards - I'd made it like Meccano with this in mind - not started on the plumbing yet.

Working out the correct location for the enclosure isolator and it's back panel DIN rail took far longer than it should but I think (hope) it's in the right place. Then I drew up an enclosure indicator panel in Autocad, cut a plastic template from it using the Laser Cutter, marked the door accordingly and cut bits out with the angle grinder.

The four temperature indicators and an LED 'Live' light will mount on a separate panel that will attach with spot welded studs.

Then it was time to paint the rear of the electrical enclosure, that got forgotten last time, and both sides of the enclosure door. I know that I've inverted the door slightly prematurely so the inside paint will be marked - ah well who can see - it's inside !

[awemawson]

Time to make an Indicator Sub Panel for the front of the enclosure.

I CNC plasma cut a version of the previous drawing for the template in 2 mm Zintec steel but without the mounting holes. This panel will be fixed with studs welded with my stud welder on the back.

Having filed and fettled the panel I did a couple of test stud welds to check the settings then went ahead with the real thing. After a sand blast and coat of zinc rich paint it was cooked a bit with a heat gun, and a coat of satin black sprayed on just the front face. Another cooking with the heat gun and it was ready to populate.

Firstly checking which way up the four indicators go and marking their rears I pushed them in, retained by plastic grippy ears moulded into them. Add the power indicator and we are ready to fit it.

I put the enclosure door hinges back on, mounted the door, fitted its two locking catches, and also the mains power interlock mechanism, along with the enclosure internal rear panel onto which all the components mount. (This was needed to check alignment of the power interlock)

Then at last the indicator sub panel could go on. Nothing wired up yest - I still need to mount the 16 amp 3 phase input socket on the rear.

[awemawson]

I thought that I might as well cut out the mounting plate for the 16 amp three phase mains input socket - when that's fitted I can wire and test as I go.

So just a 125 mm x 140 mm 6 mm plate with a few holes in it - usual thing - drawn in Autocad, cut by CNC plasma but it needs painting before fitting. Rather than rattle can black I decided to use the silver hammer finish paint as it is basically part of the frame. Not worth getting the spray gun out I thought, brush paint it. BAD MISTAKE 

What a terrible finish brush painting hammer paint gives ! I had to wipe the entire sticky mess off with Xylene, and do what I should have done in the first place - get the spray gun out.

Came out OK in the end, and to be honest using the small touch up spray gun doesn't involve too much in clear up afterwards - remember next time 

[hermetic]

There is a knack to brush painting  hammer finish! I don't know if it applies to that particular paint, which we discussed some time ago, and I bought 5ltrs of, because I haven't used it yet, but I find that the best you can do is experiment with different amounts of thinning, depending on how thick it is as delivered, and then put it on fairly heavy in a warm room, brush it out quickly in straignt lines, then leave it alone. The more you brush it, the worse it gets!
phil

[awemawson]

The problem that I had was the the 'hammers' were coming out far too large.

I think the best approach to brush painting this stuff is not to 

Spray for me from now on.

,
. . . I got that socket mounted 

[awemawson]

A solid day plumbing today. Theoretically just soldering up the bits that I had previously dry fitted, but lots of sealing screwed fittings, and adapting the plastic fittings to the tank.


I couldn't for the life of me see initially why my pre-cut bits were SO far out - it all became much clearer when I realised that I'd put the heat exchanger in upside down 

. . . still barring leaks that should be the plumbing finished when I've blanked off a 1" BSP redundant hole in the tank. Probably need to make something 

[John Rudd]

A solid day plumbing today.


I couldn't for the life of me see initially why my pre-cut bits were SO far out - it all became much clearer when I realised that I'd put the heat exchanger in upside down  :bang

You should have marked the orientation of everything as you had it assembled before you took it all apart.,,,

[awemawson]

A solid day plumbing today.


I couldn't for the life of me see initially why my pre-cut bits were SO far out - it all became much clearer when I realised that I'd put the heat exchanger in upside down  :bang

You should have marked the orientation of everything as you had it assembled before you took it all apart.,,,

John, it has a blooming great arrow and UP  in large letters 

[awemawson]

Never throw away old brass plumbing fittings !

Looking through my odds and sods box produced a 1" BSP female to 1" compression elbow - the female bit contributed a nice 1" BSP back nut once sliced off on the lathe. Then I found a 1" BSP male to 3/4" BSP Male nipple, and a 3/4" BSP blanking cap - all assembled into a 1" blanking plug ready to go in the hole in the tank tomorrow 

[tom osselton]

John, it has a blooming great arrow and UP  in large letters 
[/quote]
I heard real men don’t read instructions!
Or is that just a IKEA thing?

[hermetic]

The problem that I had was the the 'hammers' were coming out far too large.

I think the best approach to brush painting this stuff is not to 

Spray for me from now on.

,
. . . I got that socket mounted 

too large hammers eh? never had that problem before, and I must admit
 I almost always spray , but as you say, cleanup and gunwashing is a pain if you only have a bit to do!
Phil

[awemawson]

So having fitted that 1" BSP bung in the tank I had to turn my attention to what to do to support the 'house water' inlet and the overflow pipe. Although the plastic tank is quite  rigid I don't want pipes hanging off it unsupported. I came to the conclusion that yet another 6 mm plate was called for, suitably pierced, for fittings to run through and clamp to.

Bit of a mare measuring up precisely where the holes need to go - I ended up with three iterations of plastic templates before I was satisfied. Straight to spraying this time, no messing about with brushes 

Having  done that I turned my attention to a  bit of wiring. I wanted to get the thermometers at least, wired up. I've run three phase to the overload trip, and a single phase feed to the low current breaker feeding the 12 volt power supply for the thermometers. I've temporarily connected a single phase input for testing, so the thermometers are now powered up, but their sensors are still just dangling in the electrical enclosure. The 12 volt 'Power On' indicator proved to be a useful commoning point for the four displays.

While I was doing this, Andy arrived and started concreting in the surround to the manhole cover, and the slot through the path where we ran trunking under the re-bar. He has cast the 'roof' for the pump house off site, but it's still too green to move - scheduled for Friday evening.

Hope to get the pump electrics connected tomorrow.

[modeng200023]

Just a thought Andrew, have you been able to test the generator under the expected load conditions?
You are plowing on with the other parts of the project but it would be a shame if after all this work and dedication that the project failed due to a defective power source.

I'm sure that with your normal thoroughness you have covered this but I just wondered.

John

[russ57]

He'll  just have to rebuild that too...

-Russ

[awemawson]

I've only been able to load the generator up to 16 KVA and it didn't even notice that it was loaded !

Yes that IS one of the imponderables, also I don't know that the big blue furnace driver will work at high power either as it's only done low power 'pings' recently.

These things are like skittles, you need to keep knocking them down one by one as they crop up

[awemawson]

Today I completed the wiring in the Electrical Enclosure - apart from running the thermistors for the temperature indicators to their relevant pipe on the heat exchanger where they will be Ty-Wrapped  with a bit of thermal compound for good contact. But I don't want to do that until I've leak tested and proved the plumbing.

Also got the SWA cable run to the pump house and wired giving a pair of 13 amp sockets - one for the pump and the other probably for trace heating to prevent freezing.

A temporary roof comprising a pig herding board will have to suffice until tomorrow night when Andy brings the slab he has cast.

[awemawson]

First thing this morning I finalised all the plumbing for the house water input, tank overflow, and the flow and return to the furnace including the end terminations on the rubber hose that joins the chiller to the furnace driver. Fittings are sealed with Loctite 542 that is handle-able in 15 minutes but really needs 24 hours for a full cure.

So now the unit is functionally completed (it may get some mesh panels at some time) but it needs leak testing - due to the Loctite 542 this will have to be tomorrow.

I turned my attention to outside works. A trench is needed through the goose field to take the flow and return between the foundry and the bore hole. There was a fence running parallel to the foundry that pre-dates it's building (where it is was just a fence enclosed yard outside the workshop) - fence no longer needed and posts rather rotten so it had to be grubbed out first, along with an Alder tree that had self seeded behind it.

Then I scraped the ground clear of various piles of earth and weeds that had accumulated followed by digging a trench for the pipes going through the gate opening and running practically to the south end of the foundry. This means that there is only about 15-20 foot of trench to dig to complete the run, but will have to been done by hand as there is no room to get the JCB803 in there.

. . . .getting there . . . 

[awemawson]

This morning having linked both sides of the chiller into one continuous loop for testing I filled the new chiller tank and started leak tests - all good EXCEPT for the plastic feed from the tank to the Grundfos pump that has a slight drip. I'm not entirely surprised as I wasn't particularly satisfied with this pipe run - it is of course rather a pain to sort out. I did try a crude bandage of self amalgamating tape squashed with a Jubilee clip as a temporary fix but it wasn't having it. Of course when the pump is running, as it's under suction, it doesn't leak, but I'll have to re-work it somehow.

But the good news is that all the rest of the pipework is sound and good to go 

Then I started on the pump from the bore hole, making up a weighted suction hose using one of those house bricks that has holes rather than a frog, as this allows it to be securely tied to a safety rope. Weighted as otherwise it curls all over the place.

Once this was secured on the pump and lowered down the well, it was a case of a few alterations to the existing 25 mm MDPE plumbing feeding the horticultural area, and running 32 mm MDPE from the pump to a Tee junction feeding this modified pipework. The 32 mm will continue in the trenches to the foundry but currently just goes to a stop cock for testing.

The pump control unit has a male 1" BSP plastic spigot at the bottom for feed from the pump, and at the top for flow out. Both gave horrendous problems getting a good seal, having to be re-made several times - I loath plastic screwed fittings! But we got there in the end.

The final flow rate, although I've not yet measured it, seems excellent.

[mattinker]

That's really coming together!!

[hermetic]

Watch that suction pipe, the corrugations caused me no end of trouble to get it sealed! It was stopping the pump lifting on my rainwater recycling rig, and I eventually use ptfe and two jubilee clips to get it to seal! It was leaking where it joined the foot valve, and allowing the pipe to drain out!
Phil

[awemawson]

Touch wood ATM that bit is OK  (the inner wall is plain - corrugations only on the outside) but I've just noticed a weep from the upper 1" BSP plastic connector 


. . . .more re-work needed

But I think that I've found a simple solution to the 'tank to Grundfos' pipe leak, hopefully suitable bits ordered

And again , hopefully, the rest of the trench is being dug tomorrow

[awemawson]

First thing yesterday I finished hand digging the pipe trench, and have the blisters to prove it This first part of the trench is quite shallow, so once a few inches of soil are covering the cable and pipes I'm putting old roofing tiles topped with warning tape then fully back filling

Then having identified that I still had some 4 core 6 mm SWA cable (53 amp rated) left over from the Tractor Shed build, unrolled it (on grass to avoid scratching the sheath) and found that there was 15 metres on the reel.

Careful measurement of the only possible route from the main distribution board to a suitable spot in the foundry for a sub-panel showed that it was tight but just about achievable length wise - on this basis I ordered up a 4 way 3 phase panel and started drilling the necessary holes.

Both the main workshop and the foundry wall that needed drilling have changed their form several times over the years - the main shop is timber feather edge clad, but on the welding shop side I've built a fire stop from 100 mm block-work, and on the workshop side it's been foam insulation sprayed and lined with 18 mm OSB board, so the aggregate thickness is quite considerable and fun to drill holes in. Entering the Foundry, the only route was through the 6 mm web of an RSJ up in a tight corner, the other side of which was again ultimately feather edge board with other layers between.

In all a fun time but the cable got there in the end - length limitations mean I can't put the sub panel quite where I wanted, but it'll be OK. From this panel will radiate feeds to two 16 amp commando  sockets (for new cooler and pottery kiln), several twin 13A sockets and the lighting circuit.

Now I need to cut a load of box section to weld into the structure of the foundry to support the sub-panel sockets and a water panel for flow and return from the bore hole.

[AdeV]

I have to say, this is quite an amazing project.... I really hope the thing works for you after all this effort!

[awemawson]

Well Ade, it would be rather nice if it does

And if it doesn’t , well there’s another challenge to tackle.

As I sit here typing a friend is putting sealant dope on the corrugated cement roof as it was laid to too shallow a pitch and water tracks up the valleys when it rains and leaks in at the sheet overlaps. Seems to be pretty good stuff with 10 mm fibres to bridge gaps. At the price it should be fantastic 😀
 
It’s called Cromapol and has some pretty good reviews

[hermetic]

Chromapol is the dogs whatsits Andrew, It is expensive, but cannot be beaten for roof repairs, especially flat and built up felt roofs. Sweep the water off and apply it straight to the wet roof!!! as it settles into the leak the water comes up through the chromapol, I did not believe it till I used it.
Phil