Author Topic: Resurrection of a CFEI 100 KVA Induction Furnace (Read 212201 times)

hermetic · « **Reply #175 on:** April 21, 2020, 10:45:38 AM »

They look good, a larger version of the HW reservoir exchanger in the horrid combi boilers. I think you will heed to filter your borehole water to keep from debris clogging. It is all coming together!
Phil.

awemawson · « **Reply #176 on:** April 22, 2020, 06:15:07 AM »

Yes definitely some form of filter Phil even if it's only a very fine mesh - suggestions welcome

This morning the last half of the foundry floor was due for its last coat of paint so that went down first thing. I had to start a second tin, and the colour was distinctly more 'elephant' than 'blue grey' but I don't suppose that it matters much

While the paint was drying I put Phil's excellent suggestion to start with a needle scaler on the manhole castings into effect. It hadn't occurred to me for some reason, and I have to say for this application it was much less hassle than setting up the big Hodge Clemco, and made less mess. I got this needle scaler probably 30 years ago when I stripped all the paint and bondo off my Bridgeport before repainting, and I must say it's excellent. For this job I used the coarse needles - the Bridgeport got the fine ones !

It took perhaps 90 minutes to do the cover so not too bad at all. I still have to do the frame, but I came in to have a bit of a rest and upload this.

As is often the case, the casting revealed a bit of the construction of the original pattern, screw heads showing in the metal. No doubt the pattern would have had those heads puttied and painted, but in use the putty plug has fallen out.

russ57 · « **Reply #177 on:** April 22, 2020, 06:27:25 AM »

It seems to be often the case that a whole series of roadblocks seem to all collapse at once and significant progress suddenly appears...
A week ago, no chiller, no water, no heat exchanger. Now you just need a little pump and filter and you could be melting metal...

-Russ

nrml · « **Reply #178 on:** April 22, 2020, 06:39:34 AM »

If you are going to be storing the water in IBCs, Alum treatment might be more efficient and hassle free than filtration.

hermetic · « **Reply #179 on:** April 22, 2020, 08:15:12 AM »

NRML may have a good point there! it all depends on the amount of suspended solids in the water after the borehole has pumped clean. I have a rainwater reuse system on the workshop which is based on an underground brick beehive cistern , probably of pre 1900 origin, which is fed by the roof water which contains leaves, bird lime, and the cidery residue from my neighbours apples which fall onto my roof! I am using a 1" pump with a foot valve which is suspended from a float about a foot below the water surface. the pump pushes water through a standard water filter. I clean it only occasionally, but it never seems to clog up. With this type of filter housing a wide range of different cartridge mesh sizes are available.

awemawson · « **Reply #180 on:** April 22, 2020, 09:17:27 AM »

Russ yes quite a bit of progress recently, but loads more to do. I think one problem is going to be relocating the generator, as in these lock down days I can't get someone to work with me - you can't keep your 2 metre separation when push, pulling and rescuing errant rollers moving a few tons !

I'm hoping not to have to store water, and rely on what the bore hole can produce 'on demand' - I'll have another intensive pumping session in a few days now I've got the petrol water pump running again and see how low I can get it, and actually measure how quickly it recovers.

So after a spot of lunch I resumed work with the needle gun and finished off both sides of the frame casting. Underside is just a flat surface so was very quickly done, but the upper side is rather fiddly - it's not come out perfectly as it's proving impossible to accurately direct the needle at vertical walls in channels, but it's perfectly serviceable. To be frank were I to paint it it probably needs a quick tickle with the sand blaster but it's not at the top of my priority list at the moment.

So the to do list:

a/ Determine final location of Furnace Driver, Furnace Body (ies), Water Cooling equipment.

b/ Run single and (low power) three phase power to the appropriate locations

c/ Run water main from bore hole to foundry in a trench (plus dig trench)

d/ Run power for bore hole pump from foundry in trench

e/ Run (high power) three phase from generator to foundry in (another) trench

f/ Run compressed air to Furnace Body location

g/ Sort out a pump / filter arrangement for bore hole

h/ Sort out large bore drain plumbing from heat exchanger exhaust to nearest surface drain

There are a few issues with the various trench / conduit runs as other services are in the way, and also concrete paths, and some plonker has just put in a substantial concrete base for an Oxy-Acetylene storage cage JUST where the bore hole output pipe needs to go

russ57 · « **Reply #181 on:** April 22, 2020, 09:41:21 AM »

See, hardly anything left to do. ..

As I have been heard to say on occasion, the first 90% is done, now just the last 90% to go...

-Russ

awemawson · « **Reply #182 on:** April 23, 2020, 07:33:45 AM »

Having fixed the Honda WD20X petrol driven water pump it was time to do another trial pumping of the bore hole. My intention was to pump as low as possible and try and get an idea of the structure, and rate of water return.

My suction hose, complete with it's strainer and one way foot valve is marginally over 5 metres, so I was limited by that length - (of course the absolute maximum would have been 32 foot or 9.7 metres, that being the Torricellian vacuum limit for supporting a column of water)

It only took 48 minutes, shifting a calculated 27,600 litres (or 27.6 tons if you prefer) at a great gushing rate into our stream, before the pump was gulping on air having reached the end of the pipe. An impressive performance for a pretty tiny and rather old pump, and certainly an impressive gusher into the stream.

I made several attempts to take decent pictures of the inside of the bore hole, but all are pretty hard to make out - I even lowered a 240 volt LED flood light on a rope in a rather gingerly fashion, but still not too good.

The construction seems to be 24" concrete sections with integral steel steps for the first couple of metres, then it widens out to a significantly wider bore, but not concentric with the first bit, which is offset so the two circle meet tangentially.

There certainly seems to be enough for my modest 45 litres / minute for a few hours every now and again

mattinker · « **Reply #183 on:** April 23, 2020, 08:05:06 AM »

Promising!

hermetic · « **Reply #184 on:** April 23, 2020, 08:48:30 AM »

And it looks pretty clear and clean too!

awemawson · « **Reply #185 on:** April 23, 2020, 09:28:52 AM »

It does have a slight tinge to it, and of course the walls of the borehole are rather brown with (??) muddy deposits, so I'd like to filter it - I'm sure it would be fine for watering gardens and live stock, but . . .my heat exchanger . . . not sure !

hermetic · « **Reply #186 on:** April 23, 2020, 01:41:57 PM »

If it is high iron content, that would eplain the brown tinge , maybe build some magnets into the filtration. Back to the DHW auxillary heat exchenger on the combi boilers, the one on my now defunct ravenheat was stainless, and used to clog with the magnetite from the CH system, it used to get an anual clean out with acid of some sort., maybe include a magna clean or similar in the water line, or a couple of round ferrite magnets in a filter housing.
Phil

awemawson · « **Reply #187 on:** April 23, 2020, 02:36:23 PM »

I keep meaning to lower a rare earth magnet on a thin string and see what it attracts - goodness only knows whats down there

Looks like I'm going to need 32 mm MDPE pipe to get the flow rate, which is a pain as I have quite a bit of 25 mm and also it's going to be mighty fun manoeuvring it down the hole with a heavy pump (18 kg) on the end as well as mains cable and safety rope. Might need to rig a gantry of some sort

AdeV · « **Reply #188 on:** April 23, 2020, 02:41:18 PM »

Out of interest, how long did it take for the water level to recover from the 5 metres you pumped out of it?

awemawson · « **Reply #189 on:** April 23, 2020, 02:58:31 PM »

It's still not back there Ade - when I last looked a couple of hours ago it was back to about the lower edge of the smaller concrete sections - actually it's quite hard to judge exactly where the level is.

Last time it was up to six inches from ground level after a couple of days which make me think that there must be a bit of artesian well acclivity going on as the ground slopes away quite a bit from the top of the bore / well / whatever it is across the site and down to the stream.

hermetic · « **Reply #190 on:** April 23, 2020, 03:13:20 PM »

Before you go for a borehole pump, you could drop a pipe in with a foot valve, and see if you can get the desired flow rate with a surface pump, or even a waterproof pump down the hole in the bigger area. it would be a juggle to see if you can get enough water for enough time without exceeding the 32ft limit, but weld up a good strong mesh cover for the borehole proper if you go down the mansteps!
Phil

awemawson · « **Reply #191 on:** April 23, 2020, 04:07:29 PM »

Those Man Steps are NEVER going to enjoy my foot fall on them if I have anything to do with it

I have looked at 'sump pump' types and they do have certain advantages, however the advantage of a bore hole pump below the water level is that you can be sure that it will always self prime, and is unlikely to over heat - also they tend to have quite different pressure / flow characteristics. I want reliable self starting, as now the wife has an eye on the 'free water' for her green houses and poly tunnels, and to be fair it would be pretty simple to swap their feed from a mains source to the bore hole as their 25 mm MDPE pipe happens to pass close by and currently feeds seven of our twenty nine (!) outside taps

awemawson · « **Reply #192 on:** April 24, 2020, 04:19:16 AM »

The bore hole is not recovering as fast as previously - it's come up a long way but it's still at least 5 foot from the surface. So I imagine that the upper strata were saturated, and when I pumped the bore down, like a sponge they released their water but now that water is no longer there, so what I'm seeing is more of a true rest level

It's not a problem to me as my bore hole pump will be suspended about 15 metres down the hole.

But may be a problem, and I'd welcome comments and suggestions on this, is TORQUE

Imagine a 1.1 kW long thin motor / pump assembly suspended from 15 metres of pipe / cable / stainless steel wire. It will tend to twist each time it starts and stops. In a conventional bore hole where the bore of the pipe is perhaps four inches, you can get rubber friction collars to slide on the flow pipe that grip the wall of the bore pipe to stop this. But in this situation where it's more like a well than a bore I'm not sure what is the best way to restrain it other than perhaps paddles clamped to the pump body.

hermetic · « **Reply #193 on:** April 24, 2020, 08:47:54 AM »

This is interesting https://cr4.globalspec.com/thread/26623/Submersible-pump-torque. The only submersible pump I have had anything to do with was a huge old Beresford with a glass fronted cabinet star/delta starter, which fed water to the now gone Glaxo powdered milk factory (the first in the uk, installed 1934, later became Twydale turkeys processing plant) and it just hung in the borehole, under the crane that lifted it up and down. How I wish I had photos of it. Being star/delta, it started with less of a kick. Is your pump single or three phase? Install soft start? I searched on "torque reaction on borehole pumps" and saw mention of a "torque reaction bar" so searched on "borehole pump torque reaction bar" and got a welter of info. However, the torque reaction is going to be exerted against the delivery pipe, which you would have thought would return the pump to aproximately the same position after every start. It may be that suck it and see might be the way forward (see what I did there?) It may also be that pumping the borehole will start to bring up silt and iron bacteria slime which, after it is pumped away, may improve the recovery time, assuming the bottom of the lining is perforated, and we know has been unused for a long period.
Phil

WeldingRod · « **Reply #194 on:** April 24, 2020, 10:29:39 AM »

I have a similar pump on garden hose plus cable plus rope that I use to pump out a 65 foot deep pit. I haven't had any issues with it twisting anything up.

Sent from my SM-G892A using Tapatalk

awemawson · « **Reply #195 on:** April 24, 2020, 11:36:40 AM »

I'm rather going off bore hole pumps and their complications

Turns out that DAB Jet 102M pumps will self prime sitting on the surface with a suction pipe down 9 metres and deliver the flow I need. 9 metres is more than I need so my inclination is to go that way with an above surface pump and above surface controller that integrates with the pump motor.

That solution just seems easier and safer somehow. In the mean time I've ordered 100 metres of 32 mm MDPE pipe to get the water into and out of the heat exchanger, and a whole clutch of the necessary plumbing fittings.

awemawson · « **Reply #196 on:** April 24, 2020, 01:02:16 PM »

Phil that is an interesting series of exchanges on that link you quoted. It was when I found the need to shroud the bore hole pump to keep it cooled when not installed in a narrow pipe that I thought that things were getting over complicated and looked harder for a suitable self priming pump.

. . . we'll see soon if it indeed CAN prime and draw from the quoted depth

awemawson · « **Reply #197 on:** April 26, 2020, 07:13:12 AM »

So I have a JET 102M self priming pump, control box, and 100 metres of 32 mm MDPE pipe on order along with numerous fittings - so while waiting for them I've started dismantling the defunct refrigerated chiller to rescue various things such as it's reserve tank and Grundfos pump. The case I will probably scrap, or possibly cut down into a smaller unit to re-house the tank, Grundfos pump and new heat exchanger. The jury is out on that decision at the moment.

However to sort my ideas out and make sure I've not forgotten anything I have re-worked the 'overview' diagram, as it gets a bit complicated what is fed from where - don't want anything overlooked while trenches are open !

russ57 · « **Reply #198 on:** April 26, 2020, 08:42:25 AM »

It seems like it shouldn't be an issue, but could you return the well water to the well? The sheer mass of the well ought to be able to keep the temperature rise under control, and there is no chance of pumping exceeding the supply rate.

-Russ

awemawson · « **Reply #199 on:** April 26, 2020, 10:57:58 AM »

Russ I had considered that but decided against on simplicity grounds - pipe length is about the same as I'll be using a roof gully that's about 20 metres away - I had considered running the waste water down the gutter of the welding shop roof to save 20 metres of pipe but that just seems crude !

So the task this afternoon has been to dismantle the old water chiller unit - no major complications except that it must have been assembled on a stand in the factory, as everything is fixed with nuts and bolts to the base and there is barely enough room to get a hand under. In the end I jacked up one side to gain access only to find that the tank wasn't quite empty and I was pouring loads of grubby water on the floor

Having spent an hour with an old towel mopping up round all the obstructions what is left can (I think) be left to evaporate - well over a gallon mopped up!

So I now have the Grundfos CH4-60 pump out and this will definitely be reused. I have the insulated nylon cold tank removed, that is crammed with refrigerator gubbins all of which should remove quite easily - this I probably will reuse.

The main casing is huge - I need 'something' to house the Grundfos pump, tank, and the heat exchanger along with a three phase contactor and a few water valves, filters and connections - cutting it down may be more trouble than it is worth, but I may well reuse for instance its corner upright members to create a somewhat more compact unit.

The upper part of the cabinet still holds the original temperature controller and its contactors, and also two huge slabs of cooling radiators and a big three phase extractor fan - these all will need removing tomorrow.

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Author Topic: Resurrection of a CFEI 100 KVA Induction Furnace (Read 212201 times)