I will show you how to make a very simple but effective venturi vacuum pump out of cheep laboratory material. You will need several minutes to make it. The principle of this pump is that when the water flows through the vertical tube, the vacuum is generated at the horizontal tube.This type of pump is widely used in chemistry labs for many purposes as filtrating under reduced pressure for example.
Step 1: Material
In this case I have used an 1.5 mL eppendorf tube and 3 pipette tips of 1 mL. You can use any sort of pipes as long as you follow the rule from the drawing (intro). To glue the parts I used a glue gun and to attach the pump to the faucet, I used the plastic hose that can fit to the pipette tips and a piece of a bicycle tube.
Cut one pipette tip at the place where it becomes to get narrower, about 3 cm from the top (the tip on the left), and cut the other one about 2 cm from the top. You should now have 2 pipette tips with different radii.
Cut the eppendorf tube about 1 cm from the bottom and drill a hole close to the other end as in the picture. You can cut of the cap. The dimensions don't have to be exact. Just make the parts so they can fit to each other. (See the further steps).
Cut the third pipette tip several millimeters from the top so it can come in the hole you made in the eppendorf tube but it shouldn't go deep into it.
Take the shorter pipette tip from the step 2 and push it into the eppendorfe tube from the bottom. It should end several millimeters under the hole you made. Put the pipette tip from the previous step into the hole and glue all the gaps with a glue gun.
Place the longer pipette tube from the step 2 as in the drawing from the intro and glue the gap. It should be place just a millimeter above the pipette tip on the bottom (it must be a little space between them) and still under the hole where the horizontal tube goes.
Step 7: The Pump
The pump is finished. You just have to add the hoses and to attach the hose on the topto the faucet . The hose on the bottom should be pretty long (I used about 80 cm of hose). If it is too short the pump will be weaker. It also shouldn't be narrower from the pipette tip.
To attach the pump to the faucet, I used a piece of bicycle tube and wire and it worked pretty well.
I made a significant improvement by wrapping everything with duck tape. Now you can open the tap to the maximum and the pump will be much more powerful.
Step 10: How to Attach the Pump to the Faucet (elegant Way)
You can use this method if you want to use this pump at home. Instead of the ordinary hose on the top of the pump place a piece of plastic shower hose (it fits perfectly to the pipette tip). Glue the gap with the glue gun and put it on your faucet at the bathroom where the shower hose is supposed to be.
Step 11: Let's See How It Works
Step 12: Another Variation
You can make this pump in the same way using for example a piece of a plastic pasteur pipette instead of the pipette tip on the bottom. You will just need a little narrower hose on the bottom. Test your pump and if the water comes back through the vertical pipette tip, it means that the lower end of the pump is too narrow. Just cut off a part of the pasteur pipette and it will work well (the last picture).
Do everything else as for the first variation. If the pressure in the upper hose is too high, place it in a piece of pipe (I used the pipe with the inner radius of about 13 mm. It just needs to fit well). Glue everything with the glue gun.