# Thread: Could you make a water pump that pumps water using electrical currents?

1. ## Could you make a water pump that pumps water using electrical currents?

Many of us have probably done the science experiment in high school where you run a comb through your hair than hold the comb next to the faucet. The water then "bends" toward the comb.

To my understanding, this works because the comb picks up a static charge and, since a water molecule's charge is not evenly spread, the partially positively charged hydrogen atom attracted to the now negatively charged comb.

This got me thinking: would it be possible to pump water by sequentially turning on and off electrical charges along a pipe?

I'm not sure there would be any real benefit to it, though I suppose having no moving parts would make it subject to less wear. Regardless, would it even be possible? or do I not fully understand how water interacts with electricity?

2. ## Re: Could you make a water pump that pumps water using electrical currents?

Originally Posted by trtl
To my understanding, this works because the comb picks up a static charge and, since a water molecule's charge is not evenly spread, the partially positively charged hydrogen atom attracted to the now negatively charged comb.
I don't see why not in theory. You'd need to exceed the acceleration of gravity so you'd need a sustained high charge (what you wouldn't be able to do is push the water).
Probably the easiest way would be to have a tube of moving water (have a small down slope to build up speed) and then have the charge strong enough to effectively nullify gravity up a slightly gentle slope.

Of course you have the syphon pump which also has no moving parts (once started)
Or the hydraulic ram pump if you have an existing flow to parasite off

I should have googled before thinking

3. ## Re: Could you make a water pump that pumps water using electrical currents?

Originally Posted by jayem
I don't see why not in theory. You'd need to exceed the acceleration of gravity so you'd need a sustained high charge (what you wouldn't be able to do is push the water).
Probably the easiest way would be to have a tube of moving water (have a small down slope to build up speed) and then have the charge strong enough to effectively nullify gravity up a slightly gentle slope.

Of course you have the syphon pump which also has no moving parts (once started)
Or the ramjet pump if you have an existing flow to parasite off

I should have googled before thinking
I knew about syphon pumps, but they only work if the final level for the water is below the starting level and of course you might not always have an existing flow for a ramjet pump

Never heard of a electrostatic fluid accelerator before though, I tried googling before I posted but I must of used poor search terms because I couldn't find anything like this. It uses a different principle than what I was thinking of, but the benefits would be the same... interesting.

4. ## Re: Could you make a water pump that pumps water using electrical currents?

Originally Posted by trtl
I knew about syphon pumps, but they only work if the final level for the water is below the starting level and of course you might not always have an existing flow for a ramjet pump
Googles always easier for someone else (though that's partly weak anthropocentric principle, as the times you find the right words you don't post)

In one of the books I had (I think Mum had it as a child), that I can remember quite clearly because of the strange combination,
The villains ignorance of the related fact for generated vacuum pumps meant the overly pious child heroes could get the treasure first despite having sacrificed an earlier chance to keep the sabbath (they also realised pretty early on).

5. ## Re: Could you make a water pump that pumps water using electrical currents?

Its a bit more complicated than your idea, but a magnetohydrodynamic drive works by passing current through a liquid, then using a magnetic field to push it.

6. ## Re: Could you make a water pump that pumps water using electrical currents?

Originally Posted by NichG
Its a bit more complicated than your idea, but a magnetohydrodynamic drive works by passing current through a liquid, then using a magnetic field to push it.
Yeah, the topic heading immediately brought Red October to mind. It is a technology that exists but is terribly inefficient. I may have read that it is also observable as a natural phenomenon with bodies of water and earth's magnetic field interacting as in the comb model. It would be interesting if there was actually a practical water pumping application, but I think in practice it just has some industrial use for other fluids.

7. ## Re: Could you make a water pump that pumps water using electrical currents?

Originally Posted by Imbalance
Yeah, the topic heading immediately brought Red October to mind. It is a technology that exists but is terribly inefficient. I may have read that it is also observable as a natural phenomenon with bodies of water and earth's magnetic field interacting as in the comb model. It would be interesting if there was actually a practical water pumping application, but I think in practice it just has some industrial use for other fluids.
Looks like they're used in microfluidics, which makes sense. A lot easier to etch microscale electrodes than moving pump parts I guess. Also if you wanted a very fast switching pump, it should be better than a mechanical one.

Actually, that makes me wonder if you can use MHD to make a high frequency tactile display surface...

8. ## Re: Could you make a water pump that pumps water using electrical currents?

MHD isn't really what the OP is describing (though the thread title actually applies better to it). The OP is describing an electrostatic pump, rather than electromagnetic*, and I think it could be done. I can't think of any reason you would want to, but it could be done. You just have to separate the water into droplets and then have a traveling electrostatic wave. Droplets will stick to the peaks of the wave, so can be moved with the wave, even if the actual electrodes are stationary. Separation between the droplets is critical, because otherwise water can siphon back, and you lose any pumping action.

*The most notable difference between this and an MHD pump is that this is using the electrolytic properties of water, where MHD uses the conductive properties. The conductive properties of water are not relevant to what is used in this sort of pump, and this pump would not work with mercury where MHD works extremely well.

Edit: I suppose this has the advantage of not requiring constant power, at least in theory. While an MHD pump will require constant current to maintain a pressure difference even at 0 flow, an electrostatic pump does not. Alternating oil and water instead of water and air could permit high pressures to be achieved, and then when you disconnect the electrodes it will be held until leakage drains the voltage below where it can hold it. Essentially your pump can also act as a valve, which could be extremely valuable. It only breaks down when you are getting to the pressures that oil and water mix (10s of kilobar range).

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