Anyone know how to do this. I hate getting mouthfuls of warm WVO when I have to "prime" my Harbor freight pumps. YUCK.

Ian

Can you be more specific?

Are you using it to pick up WVO from the restaurant drum ? Add straight canola into the primimg port and away you go.
Using the pump as the main mixing pump for the reactor? Set your WVO container above the level of the pump and let it simply gravity feed into it via a hose, it will auto prime at the same time. This later is what I do.Check out my reactor set up and you will see how I did it.

quote:

Originally posted by Frogmobile:
Can you be more specific?

I am looking for a way to make my pump "self priming" That the pump will actually pump air through the pump itself and not just oil.

the pump you are using is a centrifugal pump!! I think you should be able to go to "how stuff works" website to see why this would be impossible!!

it woud be against all laws of physics!!

there are tricks people use for priming this type of pump, that are easier than sucking golfballs through a garden hose. I have seen a ball valve placed over the open priming port, with a funnel over that, pour in your liquid with the pump running, when it starts to push the liquid out of the output hose quickly close the valve.

Basically the inside of the HF cheapy pump that most use, there is an impeller with very large clearances. any pump that will self prime should be able to compress air, (in theory) whereas a centrif. pump just has a spinning disk with little ridges on it. it basically works like a siphon, (have you ever tried to siphon air?) you need a liquid on both ends of the pump-housing the impeller just slightly moves the liquid and pretty much pressure differential takes care of the rest. (hard to explain right now, way too tired and overheated)

Ian Tucker,

There is a solution. Fit a reservoir on the inlet side of your pump which is bigger in volume than your suction line and have a bung on the top. Have your suction line enter this reservoir near the top. To start pumping first fill the reservoir with oil and close the bung. The pump will now be primed and will immediately start pumping. The air in the suction hose will not be enough to fully displace the oil in the reservoir so pumping will continue. No foot valve is required though it could be handy to reduce spilling of oil while handling.

OK, I suppose I should know this, but, what is a foot valve? I'm goona guess that is a bladder that you press with your foot to create suction like a gas siphoning tube that has the bladder you squeeze to prime it? Thanks, Kevin

Hello kd460

A "Foot Valve" is a one-way valve located at the far end of the pick-up which prevents liquid from draining back when the pump is turned off and so holds the prime.

A picture speaks a thousand words...

http://www.northerntool.com/webapp/wcs/stores/servlet/P...ctId=523674&R=523674

quote:

Originally posted by roac:
A picture speaks a thousand words...

http://www.northerntool.com/webapp/wcs/stores/servlet/P...ctId=523674&R=523674

OK I see what it does, but you initially have to prime the pump correct?

Ian

Yes , you will still have to prime the pump , but it will stay primed . The only way around priming the pump is to purchase a selfpriming pump . As posted earlier the problem is that the clearances are not close enough to allow the pump to prime itself . That is why the pump in question is so inexpensive . If you want to avoid priming altogether just get a better pump .
Shannon

Let me be repetitve here; YOU CAN PRIME THE PUMP BY GRAVITY FEEDING IT.Merely set whatever container you are drawing from higher than the pump's inlet port and it will self prime. This is how I feed my reactor from a preheat tank and it works great.

quote:

Originally posted by Legal Eagle:
Let me be repetitve here; YOU CAN PRIME THE PUMP BY GRAVITY FEEDING IT.Merely set whatever container you are drawing from higher than the pump's inlet port and it will self prime. This is how I feed my reactor from a preheat tank and it works great.

I know, That is what I do for my Appleseed to wash tank.


Ian

Dodgeram, you are not corrct. You don't have to get a self priming pump. See my post above.

Yes Neutral , but that is in fact still priming the pump . It is a better way of priming it than what is allowed for in the original design though . I was refering to the pumps tolerances and the inability to just stick the hose into a drum and expect it to suck up the oil .

Certainly IanTucker asked for a way to make his pump self-priming, which I agree is impossible. If you think about his motivation for asking the question however a wider range of answers becomes possible.

I made a foot valve with a piece of rubber flap and a piece of lead to keep it heavy on its seat (machined brass cylindre) By vigourously shaking up and down le liquid moves up the suction hose intothe pump and primes it. Inthis case it is water (for washing) It should work also for oil if it is reasonably warm and fluid.

Just to make a distinction in types of pumps:

quote:

the problem is that the clearances are not close enough to allow the pump to prime itself . That is why the pump in question [Harbor freight centrifugal pump] is so inexpensive . If you want to avoid priming altogether just get a better pump .
Shannon

This is not a question of tolerances. You could have the most expensive centrifugal pump in the world with the tightest tolerances, and it still won't self prime. The reason is that a centrifugal pump is not a positive displacement pump.

For a pump to be truly self priming, it must be a positive displacement pump. Three examples are gear pumps (hydraulic pumps, engine oil pumps), piston pumps (eg pressure washer, air compressor), and diaphragm pumps. Most positive displacement pumps will move any fluid, gas or liquid (though they may be designed specifically for one or the other, like air compressors). So they happily pump the air out of the line and draw the oil up to the pump. And yes, those tend to cost more.

Finest regards,

troy

quote:

Originally posted by troy:
Just to make a distinction in types of pumps:

quote:

the problem is that the clearances are not close enough to allow the pump to prime itself . That is why the pump in question [Harbor freight centrifugal pump] is so inexpensive . If you want to avoid priming altogether just get a better pump .
Shannon

This is not a question of tolerances. You could have the most expensive centrifugal pump in the world with the tightest tolerances, and it still won't self prime. The reason is that a centrifugal pump is not a positive displacement pump.

For a pump to be truly self priming, it must be a positive displacement pump. Three examples are gear pumps (hydraulic pumps, engine oil pumps), piston pumps (eg pressure washer, air compressor), and diaphragm pumps. Most positive displacement pumps will move any fluid, gas or liquid (though they may be designed specifically for one or the other, like air compressors). So they happily pump the air out of the line and draw the oil up to the pump. And yes, those tend to cost more.

Finest regards,

troy

Troy,

I think you missed the point I was trying to make. My statement was not that the tolerances differed from the blueprints, but that a self-priming pump (in Theory) should be able to compress air. A vehicle waterpump is a centrifugal pump just like the HF cheapies, it is just a spinng disk, in no way, shape or form will that be able to compress air. the physical properties are siphon based.

Big Mawka,
A turbocharger is just a spinning wheel as well, and it compresses air quite nicely. It is not a positive displacement pump either. But, if you spin them fast enough....