Thread: Replacement submersible oil pump for EDM sinker

hi John, I'm not a fluid dynamicist but I would think that oil would lower those figures. It would be a cetrifical pump & oil would be harder to push, hence a lower flow rate. also I would think a slightly lower head. Looking forward to be proved wrong, but this week I have put cooling on the mill using a centrifical pump from an evaporative cooler & using straight ATF the flow was not brilliant. Diluting with Diesel has made it quite workable. Good luck with the pump & what brand of EDM have you got?
Cheers, Ian.

Your figures seem about right with water. Two issues with oils.

Oil weighs about 70% of the weight of water. Centrifugal pumps rely on mass to operate which is why they don't pump air with any great success. This reduces efficiency.

Oil is more viscous than water which introduces friction. Another drop in efficiency.

The design used for suds pumps is already very inefficient. Ever looked at a washing machine pump? Much the same.

I am not saying it cannot be done but I would suggest some expert pump knowledge may be best. What type of pump is normally used. A submersible pump does indicate a centrifugal pump but the specifications would be important to know in relation to a replacement. If you were to buy one designed specifically for oil transfer I would imagine it would cost a lot of money but there are a number of submersible pumps of various sizes available on Ebay. For light oil it is probably just a matter of knowing what size to get.

Pumps are generally rated for use with water. How this relates to oil I don't know.

Where I work, in a winery we call these pumps "squids" for some reason. We use them for mixing smaller tanks of wine. One of my work mates said one day " it looks like we are going to have a seafood night soon". Why, he was asked? Because there are six squids lined up in Maintenance. Sigh.

Dean

Hi Johntopp,
Have you thought of using a power steering pump. I have no idea on flow rates but I know they pump steering fluid.....sometimes.

Phol

Originally Posted by Steamwhisperer

Hi Johntopp,
Have you thought of using a power steering pump. I have no idea on flow rates but I know they pump steering fluid.....sometimes.

Phol

Who's Phol? New member?

Power steering pumps can be used as hydraulic pumps (which is what they are of course) A mate of mine has used them. Plenty of pressure but like you Phil I have no idea of flow rate. They can be got cheap tho. Then they do still need a drive source which will affect the pressure. Worth a look into.

Dean

Originally Posted by Oldneweng

Who's Phol? New member?

Dean

Dammit! Heaps of credibility when I can't even spell my own name.

P. h. I. L. Phil. Yep that's it

Originally Posted by Steamwhisperer

Hi Johntopp,
Have you thought of using a power steering pump. I have no idea on flow rates but I know they pump steering fluid.....sometimes.

Phol

thought you might have moved to New Zealand Phol

pond fountain pump might get you closer to the numbers you need

cheers
Harty

I got the machine set up and operating yesterday, mounted the head on the T&C grinder, plastic tray on the table, steel plate in the tray clamped to the table. So there's nice x,y,z positioning. Successfully EDM'd a hole in a piece of steel using a tubular electrode, just a piece of copper tube around 6 mm dia. Used a little brush to agitate the oil round the electrode. Fair bit of short-circuiting involved during the burn, but the control unit handled it nicely, adjusting ram to compensate, finish wasn't too bad considering. But that's as much as I'll do till the tank is set up with a pump and new filter. Apparently FLUSHING IS EVERYTHING, so it's pointless to do any more.

You fellas have convinced me to abandon the suds pump.

Power steering pump is a good idea, no shortage of pressure with one of those, not sure about volume. Just a bit of messing around to set up. Maybe external with a belt drive, or perhaps submerge the whole thing with the shaft vertical and driven from above, just need to make a little shaft extension I guess and a motor mount. Maybe an engine oil pump is a possibility, they're pretty submersible and no worries about getting to 80 psi or so. With poth pumps I'd need to organise some sort of relief valve, just a ball and spring arrangement perhaps on the pump outlet with a long adjustment shaft poking up above the oil level.

I'd considered a diesel transfer pump from what seems to be a confusing array on eBay, lot of those seem to be 12/24V though. I'd prefer 115V (the controller supplies that) or 240/415 - just need a contactor then

Not that I know much about these things but.
How are you going to filter the electrolyte? A power steering pump* might not take kindly to the oil not being CLEAN. Though if they are cheap enough it might not matter?

Stuart

* or any other gear or vane pump for that matter.

Originally Posted by Steamwhisperer

P. h. I. L. Phil.

Out of H's Phil?

If PhD means Doctor of Philosophy, Perhaps PhIL means something like International Laureate of Philosophy. I always thought that Phil was pretty smart...

Michael

Originally Posted by Stustoys

Not that I know much about these things but.
How are you going to filter the electrolyte? A power steering pump* might not take kindly to the oil not being CLEAN. Though if they are cheap enough it might not matter?

Stuart

* or any other gear or vane pump for that matter.


Out of H's Phil?

you really do have bionic eyes Stuart

Originally Posted by Michael G

If PhD means Doctor of Philosophy, Perhaps PhIL means something like International Laureate of Philosophy. I always thought that Phil was pretty smart...

Michael

I could get used to the international thingy but I reckon any International Laureate could spell their own name at least.

You know who

I have an old edm machine here was used for removing broken tooling from castings on an assembly line.
Later on needs some heads up on this is complete and ready to fire up just unsure due to ignorance, Re fluid electrodes etc.
Not on my most urgent ''round to it '' plate. I was actually given a round to it plate made by Bendigo Pottery in the eighties a gift from my sister. John.

I have the original oil tank. It's got about six compartments. Each compartment has a hole at the top leading to the next one. The oil returns to one end then flows from one compartment to the next allowing the sludge to settle to the bottom. The pump's at the other end. Presumably the oil is fairly clean by the time it gets there, and I guess the pump inlet would be a couple of inches clear ot the bottom. The pump feeds a filter, looks like the oil filter off a truck engine, then to the work.

I imagine there'd still be some finely suspended carbon getting to the pump compartment, so perhaps a hydraulic pump would be unhapppy with that. Maybe a centrifugal pump would be the go, but it'd need some oomph. The flushing hole is typically about 30 thou and then it's common to use an auxuilary flush to clear debris from the top of the work. That nozzle looks a lot like a normal coolant one you'd find on a lathe. So you'd need pressure and volume. From the specs the equivalent water head would be about 7 M and 40 l/min - oil is going to be different of course.


The original pump was submersible, 115V powered from the control unit

Maybe something like one of these diesel transfer pumps would do the trick, but it looks like overkill, and it'd be nice to just find a 240V submersible unit, save mounting, piercing the tank and playing with plumbing

240V Heavy Duty Biodiesel Diesel Transfer Pump 55L MIN Warranty | eBay

Here is a 240 volt one John, not exactly what you want but...
You wouldn't have a pic of the original would you?

Phil
Submersible Sump Pump 240V 280W NEW | eBay

Used a 12v bilge pump for years to pump out vehicle servicing pit pit was 6 ft deep and 20 ft long would make 1 ft water 24 hrs. used to pump out in about half an hour. good volume raising 6ft not much pressure and was about 50 dollars from memory i rented that shop.the landlord near peed his pants when he saw it cos they used to get down there in gum boots and fill buckets with a large square mouth shovel. Stuff That.He was there 47 yrs before me. just jack hammered a small sump 1 end put an ice cream cont and sat pump in. it lasted over 6 yrs bought a second pump but left the garage not long after. 0.02 worth.