Resurrection of a CFEI 100 KVA Induction Furnace

[awemawson]

So cheating a bit and using an On Line water heating calculator it turns out that in theory, a water filled 1000 litre  IBC would last for 44 minutes if pumped round the furnace and furnace body (which would be dumping about 40 kW into it) before reaching the upper temperature limit.

[awemawson]

Now ideally the IBC would have a copper coil immersed in it, being cooled by the bulk of the water, which would be constantly be being replaced thus extending the operating period to continuous.

So I need a source of water - OK I have a stream but it's about 75 metres away - not impossible to pump but a pain. Returning the used water to the stream is less of an issue as the surface drains run there.

BUT

Since we've been here we've been unable to explain a 'mystery 24" manhole cover' at the back of my workshop and not far from the foundry. We've never been able to open it - it looks perhaps to have been welded shut, but not actually expended much effort on it - but perhaps now is the time because . . . .

Searching the on line bore hole database shows a borehole in approximately the same place, and details of the borehole are available on line - all nine pages of data !

http://scans.bgs.ac.uk/sobi_scans/boreholes/651959/images/12563414.html

Now if this IS the borehole, and if I can lift the cover, and if it's not been back filled there is a possibility of free water fairly close to where I need it . . . mmmmm . . . . thinks . . .

. . . any volunteers to open a darn heavy sealed man hole cover ???

[Joules]

Drill it tap it, fit a spark plug...   Now add 50’ of chain secured to cover and staked out opposite from workshop.  Once the cover has blown, you just need to follow the chain and dig out the cover....   Simples...

 

[chipenter]

We used to lift those with a tractor hydraulics , slide the pulling bar though the two keys and lift until the front wheels are off the ground , then bash round the perimeter with a 5 pound hammer , the vibration did it every time .

[Pete.]

A big lever key should pop that open. Might want to run a jetwash around the lip first.

[nrml]

Why not drill a small hole in the lid and pass a borescope / plumb line through to have a look before going through the effort of opening it. It might have been filled up or gotten blocked up with debris.

[WeldingRod]

24" is a heck of a bore hole!!!

Sent from my SM-G892A using Tapatalk

[awemawson]

Why not drill a small hole in the lid and pass a borescope / plumb line through to have a look before going through the effort of opening it. It might have been filled up or gotten blocked up with debris.

That’s a good idea

[awemawson]

24" is a heck of a bore hole!!!

Sent from my SM-G892A using Tapatalk

The November 1939 document actually says diameter at top 5 foot 9 inches 

But it’s the manhole that’s 24 inches !

[awemawson]

Glad to say that the first half of the floor had mainly dried over night with the exception of a bit by the wall where I was probably a bit enthusiastic with the sodium silicate solution.

It has made a very noticeable difference to the previously rather dusty surface - you can draw a hand over it and no dust comes off at all

So it was a case of 'rinse and repeat' this morning - moving everything to the now sealed end using the pallet truck, vigorous sweeping and vacuuming and another session mopping 3:1 water / sodium silicate solution to the newly exposed floor. The wind has got up and this lot was drying much faster as I have doors both ends.

It's my intention to give it a coat of grey industrial floor paint when the seal is thoroughly dry, and although I have the paint I don't have sufficient white spirit to dilute the first coat, and I only have one 12" floor roller. In these Covid-19 isolated days it's not just a case of popping out to get them so I've orders in place - at least it'll give the seal longer to dry (sell the positive !)

Stay safe everyone.

[awemawson]

Waiting for concrete sealant to dry is rather like waiting for paint to dry - boring 

So I had another go at the manhole cover. I'd intended to pressure wash the joints as suggested by Pete. but my brand new portable petrol washer that's only run for one day refused to start - no spark  And it's far too much of a fag to dig the big steam cleaner out from the Tractor Shed as it's buried again at the back.

So I went round the joint between the frame the the cover with a small cold chisel clearing as much rust as I could, then giving it a good talking too with a sledge hammer -  I assume it's malleable iron not just ordinary cast iron !  Still no movement so I've started a program of squirting Plus-Gas into the crack - it is soaking in so may do some good. When I've done that for a day or two I'll gently vibrate it with my Kango concrete breaker.

At the moment I'm loath to drill holes in it as undoubtedly there will be strengthening webs in it underneath that I don't want to hit, and the light on my endoscope camera is not too bright.

Re-reading the borehole survey report there are a few contradictions and I think, looking at page 6 it may be referring to 6 bores made in the period 1922 to 1962.There is also a reference to 'Back Filled it to 90 Down' however there is also a reference to 'Filled in Information from visit 16/10/62' - so who knows - certainly not me

Anyone know how I can print a copy of the 9 pages of that report ?

[awemawson]

This looks to be the same specification so I better be careful!

[Pete.]

Bit more fragile than the 60-tonners outside out site

What I would do is measure the hole diameter in the key slots. Get a bolt about 150mm long with a shank that fits closely in the hole and cut the sides off the head so it can drop in and turn through 90 deg. Get a piece of box section steel maybe 6 foot long and drill it over-sized for the bolt to allow a bit of wiggle. Measure the distance from the key slot to the edge frame and weld a chunk of flat bar on the box section such that the bar acts as a fulcrum bearing on the frame. Now pop the box section over the bolt and run a nut down it, and start bouncing on the far end to lever the cover up.

[Sea.dog]

You could save each page as an image and then print it to PDF (at least, in windows)

[awemawson]

I can only get about half a page to a screen for some reason 

[mc]

Page 9 is apparently too big for the viewer?

[mc]

And what you really want is a manhole lifter.

Utility engineers who deal with underground pipes/cables should have them in their vehicles.
You really want an Openreach cabling engineer though, as they carry hydraulic lifters.

[AdeV]

Cut a new one from steel plate, using your plasma cutter table... then have at the old one with the biggest hammer you own 

[awemawson]

Wow Morray how did you do that ? Thank you so much - all the various browsers that I tried would only open half a page at a time.

Yes a hydraulic lifter probably is the way unless I take the Ade approach, which I must say I have considered !

This morning I welded up a simple slide hammer from some re-bar and a bit of 8 mm plate - it's not strong enough, as you can see in the picture the Tee bar is bending. Ideally I'd use Pete.s approach with an HT bolt with the head cut down, but I don't have any 1" HT bolts in stock so I used what's to hand.

I will try again with something a bit stronger, but by golly this lid is well and truly stuck !

[awemawson]

I followed up on the Slide Hammer with a bit of controlled violence from a Kango concrete breaker, the idea being to vibrate and hopefully crack, the rust bond between the cover and it's frame.

The Plus-Gas IS penetrating into the lid/frame gap most of the way round but it's still not anything like free.

I suppose in extremis I could try breaking the concrete round the frame, and digging out the complete frame with lid, an then leave it soaking in Citric Acid for a few weeks 

[djc]

What I would do is measure the hole diameter in the key slots. Get a bolt about 150mm long with a shank that fits closely in the hole and cut the sides off the head so it can drop in and turn through 90 deg. Get a piece of box section steel maybe 6 foot long and drill it over-sized for the bolt to allow a bit of wiggle. Measure the distance from the key slot to the edge frame and weld a chunk of flat bar on the box section such that the bar acts as a fulcrum bearing on the frame. Now pop the box section over the bolt and run a nut down it, and start bouncing on the far end to lever the cover up.

All of the above except the last sentence. Weld two chunks of bar to it so they bear on the projections of the frame on both sides and then use the nuts on the bolts to wind up the cover like a giant bearing puller. Once the bolts are in the cover slots strut them apart with a piece of timber.

[Will_D]

Are there any visible signs of weldinding? Or is it just rusted in tights?

Welds should be easily visible!

[awemawson]

I'd initially thought that it had been welded, but my various attempts over the last few days to open it have now convinced me it is a combination of tight packed clay and rust .

I suspect these covers fit in a taper fashion - I've been working away at the junction but it's pretty solid. I'd hoped that the Kango treatment would at least have broken the bond, but apparently not.

My fear is that a trimmed bolt head in the slots may end up just pulling some the the cover round the slots out as it'll be exerting far more force than intended. Hence still scratching away at what gap there is.

[Pete.]

I have seen covers with burst key holes before Andrew. Usually on private property because a utility would get them changed.

[vintageandclassicrepairs]

Hi Andrew,
What about making a fire sat on the lid? the heat would expand the cover more so than the frame
It might be enough to break the joint free

John