# Water Pumps



## ScreamReaper (Feb 21, 2010)

Ok, so the prop I'm building is going to need a water pump that recycles a very small amount of liquid. It's going to need both an intake hose and an output hose. And when I say very small amount, I mean very small. I'll try to get a measurement later today, but off the top of my head, I'll estimate about 2oz of red (as close to blood color as possible) liquid. I have used fish tank pumps for a few props before, but not for this small of an amount of liquid. I'm by no means a pump expert and would like to get some ideas as to which direction I should go with this.

Thanks!!!


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## hedg12 (Jul 6, 2008)

Take a look at windshield washer pumps.



 Not sure how much volume they actually move, but it's not much. You also might be able to slow it down (lower the voltage or use pwm) and reduce the volume.


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## ScreamReaper (Feb 21, 2010)

Just checked that one out. That just may work. I just need to make sure it can cycle continuosly all night long, for a month straight. 

I made the measurment, and I was just about dead-on with 2oz of fluid. And it will cycle from the same source that it recycles in to as well. I don't think its going to matter how fast it recycles, as long as it doesn't suck up all of the fluid before it has a chance to fill up again. Regardless, it wouldn't hurt to have a way to vary the rate at witch it pumps.

Also, it will not be possible to submerge the pump into the liquid. I will need to have one tube submerged into the liquid to suck it up into the pump, and another tube above the liquid, so that it can flow back down into it.


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## hedg12 (Jul 6, 2008)

Yeah, I'm not sure those can handle that kind of duty cycle.

Not sure if it would work with your design, but you might think about using 2 reservoirs - one above and one below - with some kind of float type switch. That way you could let gravity do the constant work. You could use some kind of valve to regulate the flow however you want it, & when the top reservoir got low the float switch would kick a pump on and refill it from the bottom one. It'd be quite a bit more complicated than just a pump, but would give the results your looking for if you can't find a pump that will do the job.


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## Bone Dancer (Oct 7, 2005)

Do a google search for "micropumps". I found a few, but they might be a little pricey.


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## billman (May 3, 2006)

How about those pumps for mini tabletop waterfall fountains. You could buy the fountain and take out the pump.

Also, I found some videos on youtube on how to make a small water pump. Here's one:





Found this mini HO water pump for model trains. Might work, $11.29
http://www.hobbylinc.com/htm/bac/bac42219.htm


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## corey872 (Jan 10, 2010)

One thing to keep in mind, a lot of these small/cheap pumps won't be self priming. They need to have liquid in them to begin the pump cycle - if they have air, they will just freewheel. So you will need to make arrangements to have the pump at or below the level of the resting liquid.


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## ScreamReaper (Feb 21, 2010)

billman said:


> How about those pumps for mini tabletop waterfall fountains. You could buy the fountain and take out the pump.
> 
> Also, I found some videos on youtube on how to make a small water pump. Here's one:
> YouTube - poor man's mini water pump
> ...


The pump in the YouTube video probably won't work because I have no way to submerge the pump into the liquid. However, that train pump may just do the job. Thanks! I'll let you know what I find out.


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