Power steering / engine oil pumps use for waste oil.

Having owned and maitained about 20, mostly GM cars in the 70 - 90 era I have a lot of old power steering and engine oil pumps. Now I need to pump waste vegetable oil through a de-watering and particulate (3 micron) filter to a storage tank. I have looked at the price of a commercial item and am horrified. It needs quite a small flow at about 50 psi.

I have looked at engine oil pumps and they have a pressure relief valve that just releases into the sump. I was thinking of putting a much heavier spring in so it will not operate, but the PS pumps do not have this problem.

Given that I am willing to modify and sacrifice any old pumps I have, I rigged up a motor drive to an old PS pump and filled it up with WVO with the outlet connected to the inlet. It was only running at about

100 rpm but nothing at all happened. It did not prime or circulate. Thinking I had a broken pump I tried another with the same result. Both these pumps were working when I took them off old engines and I wonder why this should be. I assume that looking from the "front" the pump will rotate clockwise. ( I did reverse the rotation of the motor, but it did not change anything.) The oil is obviously a bit thicker than Auto transmission fluid, but I thought it would pump in the end, if only for a short while. I assume that these pumps are gear type and if I could get the pulley off, (does it just pull off?) I would get it apart to see what is happening.

Can any one explain this and suggest the best way to cheaply pump veg. oil

Thanks for any suggestions George.

Reply to
George
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Or you could completely disable the relief valve by putting a solid piece of bar stock in the space where the spring normally goes...

GM/Saginaw power steering pumps are vane-type pumps, and the vanes are held in contact with the outer pump housing by centrifugal force. When operated at low RPM, the vanes never "fling" out and seat against the housing, so the pump does nothing. At a certain RPM, the vanes will pop out and the pump will begin pumping. 100 RPM, is barely over 1 turn per second- WAY too slow.

Reply to
Steve

Thanks Steve, that certainly explains why it does not pump. So I suppose I should have more like 1000 rpm to make them energise. That is a pity as I don't need a high flow and I didn't want to use a high power electric motor, to get it up to that speed I will need at least

1 hp I reckon. I would still like to get the pulley off!

I think I shall go back to the old engine oil one - at least that is going to pump from very low rpm. I can make a coupling and direct drive it.

I am still a bit concerned about leakage, though, if this leaks a bit from anywhere into the sump, it is not a big problem, but if it starts dripping waste oil all over the place - it's really not so good.

The best way is to lash it up and try it.

Thank again, regards, George.

Reply to
George

Nahh, you can get it up to high speed without a lot of torque. Get that pulley off, put a bigger one on, and drive it with the pulley!

--scott

Reply to
Scott Dorsey

I may try that as it is already all connected, but it is only 1/4 hp and it will be driving the oil through a very fine filter, I still think it will prove to be too much of a load. I chose the smallest pulley on the motor I could find because I didn't want a big flow. I shall let you know if it works after I try it tomorrow, it's dinnertime here in UK now.

Do you think there are any seals which will not like veggie oil?

Thanks George. Diesel up to six pounds a gallon now! That is about

12 US$.
Reply to
George

that's a lot of money!

Reply to
dennnischu

that's a lot of money!

===

Yes the cost of petrol and diesel (diesel especially) is going up on a day by day basis. The highest I've seen near me is 1.30/litre for diesel which is 5.91/UK gallon or 4.72/US gallon. Using today's exchange rate of

1=$1.88, that's 4.72*1.88 = $8.88. Not quite as much as the OP said - he forgot to convert UK to US gallons and assumed 1=$2 exchange rate - but it's still a lot of money. Make us jealous in the UK - how much are gas and diesel in the US, typically, these days?
Reply to
Mortimer

Actually that is Imperial Gallons which I think are a bit bigger than US ones.

A busy day today but I did change the pulley (and the motor, for a slightly bigger and faster one and away it went, - oil rapidly circulating round the transparent pipe from exit to input. So far so good, but a couple of things do occur to me. What about the reservoir. There may not be any suction in the input pipe. and so how do I maintain the volume in the reservoir. It is OK on a closed circuit like I have now, but how about pumping from a tank, through a filter to another tank. I am not sure if the cap is airtight, in fact it cannot be to allow for temperature volume changes.

I suppose I could permanently close the cap and then, if anything gets pumped out there will have to be a suction to drag some more in. I may go back to an engine oil pump just to see if it does leak at all, because if it does not I feel this would be the preferred way to do it.

I have been making a mounting plate for the 3 micron filter, as whatever pump I use this will be needed. I may get round to this tomorrow.

Regards George.

Reply to
George

Sometimes it is better to filter using simple hydrostatic head if you have the time to wait...

If you want to reduce the flow on your pump, install a partial bypass line, from high pressure side to intake...Put a metering valve in that line and you can let the pump reach its operational speed, but you can still throttle the fluid such that you dont put too much pressure on the filter.

Reply to
HLS

Goood idea!

Today I got my first 5 gallons or so filtered, but I was not very happy with the process. Even though I found a smaller motor pulley, it was going too fast and sucking air in via the filler cap. The pressure across the filter was too high as well and got up to about 60 psi. I think if I closed off the filler cap, got an even smaller belt pulley to make it run even slower AND put in your bypass, I will be in business.

Like I said earlier I do have an engine oil pump which is very small and neat but has an awkward drive rod and no seals. I have machined a groove in the drive shaft and inserted an O ring, which may do the trick there and blocked up the pressure relief escape. I just have to turn it in a satisfactory manner. With a slower motor and a bypass I think this will be OK. Only one input and one output.

I shall put sealer on the faces of the two halves of the body as there is no gasket and give it a whirl. What I have now is more or less working, but all the bubbles being drawn in caused it to expand rapidly when the motor stopped and it poured oil out of the filler cap which does not seal at all. It made an awful mess.

Ideally I want a lower pressure, slower flow which I can leave on for hours at a time as I am pumping from one 300 gallon tank to another, i.e. from a pre-filtered and settled tank to a 3 micron filtered and de-watered tank, prior to putting it in my truck.

Thanks for your comments, regards George.

Reply to
George

Kudos to you George, for trying to do something many of us would love to do.

Disclaimer: not an engineer, nor a pro mechainc...but a big DIY'er... personal opinions follow...your mileage may vary :)

Been following the thread; my first thought was....I'd use an engine oil pump, not a PS pump. A Gerotor type oil pump will flow oil at a lot lower pressure, and should deal with thick oil and impurities better than a vane PS pump too. I'm thinking a Small block Chevy type oil pump w/pickup...just add a driveshaft and figure out how to port the output to your next tank. There are also commercial electric gerotor utility pumps out there in the $50 range that might work, too. I use those to change oil in gearboxes on radar systems.

Best of luck with it...Don

Don Byrer KJ5KB Radar Tech & Smilin' Commercial Pilot Guy Glider & CFI wannabe kj5kb-at-hotmail.com

"I have slipped the surly bonds of earth; now if I can just land without bending the gear..." "Watch out for those doves..."

Reply to
Don Byrer

ending the gear..."

Thanks Don,

The oil pump I am trying to modify is a small block 350 cu.in Chevrolet pump! I have lots of them.

I did run the power steering pump for quite a while today, the only problem was that it was sucking air in via the filler cap. I don't see why a bit of air should upset the filter, so I did about 40 litres and will let it settle to let the bubbles rise to the surface. Then I can inspect it carefully for any sediment and also boil a bit up to see if any moisture remains.

One thought did occur to me today, I wonder if the ps pump body will come off easily, as then I can probably connect directly to the pump mechanism inside, one way or another. A bypass valve can control the flow. The pulley will have to come off this time. I have an older psp which I might tear apart tomorrow. I cannot find any repair procedures for these pumps so maybe they are a replacement only item.

Regards George

Reply to
George

I am also not an engineer, but someday I aspire to be a mad scientist.

I don't know if this would help you, but here's how -I- would probably do this:

I would have 3 tanks. One tank would be at ground level or whatever is easy to fill- it will be the one to have the pump in it (whatever pump you get to work is fine). It would pump (upwards) directly into a second tank. This second tank would then drain via *gravity*, through the filter down into the third tank. Increase the number of filters to speed up the filtering process.

The pump would be turned on and off by a float in the 2nd tank. If you have enough drain legs it probably would drain so fast you wouldn't need this at all. All three tanks would have a filtered vent on the top to equalize pressure to the atmosphere.

-ph

Reply to
phaeton

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