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Will this water pump work? 2.0 Answered

I have updated my design for a simple water pump with the comments on my last one (https://www.instructables.com/answers/Will-this-water-pump-work/) in mind. It's thought to be hand- or windpowered and lift water 30-50 cm (1-2 feet i suppose). The cylinder will be about 10 cm (4 inch) across and the piston head 2 cm (1 inch) thick. The outlet is far too small in the picture.


It will work if:

- change your "puck" material, try tight rubber, is more simple if your cylinder has 10 cm and you do not have to drill holes in a wooden material, keep in mind that some wood can inflate in presence of water. Also, pay attention to your rubber piston to be 3 cm thicker

- inlet hole should be under the pump because your simple valve will not work if cylinder walls are rounded :), your valve will not seal. So move the inlet hole at cylinder base.

- outlet hole has to be double than inlet, because of pressure.

- if by lift 30 50 cm you mean lift through your inlet hole then is fine, this one will work.

Advices :

- at first use you may need to arm the pump with water in upper piston to create vacuum till your inner chamber fill with water ( fi you do not understand me here, you can ask)

- if you make a soft valve, you have to test how soft it is, beucase you may lost water in stand by. An ideal pump is to serve water at every use, no need to refill it to work.

One issue: Having a pivot on the piston means there's a risk of the piston tilting and your losing the seal. You either need to make the piston a long enough cylinder to keep this from happening, or you need to firmly attach the shaft perpendicular to the piston so it holds the piston in the right orientation.

The outlet and inlet could be the same size, so neither is limiting flow more than the other. Having the outlet be a bit larger does no harm; having it much larger probably doesn't help.

Yes. The shaft will still have to travel in a vertical direction, but I presume you're dealing with linear translations (your slotted lid) because you're driving directly from a cam, rather than using a secondary pivot to reduce or eliminate translation.

Oh, I forgot that one (can't see the picture among the old comments although I remember you posting it) This would make the connection between shaft and piston head a lot easier when it doesn't have to move. Also the height and width of the cylinder if more free when you don't have to think of the sideway movement of the shaft.

True that. Less wear and tear as well. However, you have to have room for the pivot and cams.