1 The sponge should be light and when it soaks water, it should sink.
2 I think that it should be made of relatively hard material.
3 You may need some spacing or timing mechanism to keep the balls the required distance apart.
4 Use hard clear pipes so you can see what is going on inside. Perhaps Plexiglas or perxpex.
5 Perhaps you can power your experiment with a small air pump. (Only the air lift part of a pulser
pump is being changed).
6 Perhaps (if you are using a pulser pump to power your experiment), you can have the air inlet to
the air lift section about 70% or 80% of the maximum that it could be. You might not understand
why until you try it out!
So there they are, I hope some of you try the thing and make it better!
7 The pump should also work without the sponge balls.
The animated picture lacks detail (only one sponge ball is shown), scale, fall-back etc. but it should give you an idea what I mean. Air to power the process comes in through the
black pipe on the left. Improved image! 6th September
Please use this link to build a simpler pulser modelmodel instructions
use this link to make a split process model (More complicated)
Below you will find a diagram of a suction pumping system which you can make from jam jars, rubber bungs and rubber tubing! It need have no moving parts. Instead of providing air under pressure as the pulser pump does, it produces vacuum. It is very much a toy but one which will give a lot of enjoyment as you try to tweak the process for better performance. I now include an animation of the suction pump at Suction pump index There are hundreds of ways to make it better!
You can use a valve instead of a constriction, you can have 2 sets of pumping chambers, find the optimum height for pumping stages, or adapt the process to pump in one long stage like a pulser pump.
It works scaled up too. I am not sure how tall you can make the suction maker (pipe walls will collapse due to the vacuum). I do not think that such a pump is good for the environment because a fish passing through it would suffer swim bladder damage, aquatic insects would have their breathing tubes damaged and I do not think that it will change the oxygen levels in the stream in a beneficial way. This jam jar suction pump was actually my first pump. I thought it up while distilling hexane in a laboratory (boring job watching liquid bubble through pipes) and it is based on the Krebs cycle which we learn about in biochemistry. The pulser pump evolved from my experiments with it.
Pulser index page