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Unread 10/11/2003, 02:03 PM   #1
thunt
Registered Member
 
Join Date: Jan 2002
Location: Devon, UK
Posts: 60
DIY "Stream" style pump

Currently modifying a Maxijet using a propellor to achieve a higher flow rate.

I glued the impellor to the shaft. Then, drilled out the plastic caps that either end of the shaft pushes into. Now, the impellor and shaft spin. By cutting down the impellor, so all I'm left with is mainly the magnet you end up with quite a long shaft at one end.

Instead of using the intake/outake that fits onto the powerhead, I've replaced this with some modified perspex, so now the shaft (that spins) sticks outside. So now you've got an underwater motor with driven shaft!

It's a maxijet 1000 impellor and I've tried it in a maxijet 1000 body and also a 250 body, with the same results from both, so maybe it's the impellor that governs the powerheads output.

Anyway, this thing really shifts water. Even in the MJ250 body its impressive. To descibe the output - if you have a powerhead running near the surface pumping end to end, you can see the narrow stream of water as turbulence at the surface.

With the propellor running, by half way across the tank, the entire width of the tank is turbulent.

With a powerhead, if you put your hand in front, you can feel the current immediatley in front but not to the side. Not so with the propellor - the current is very widespread. I'm using a performance powerboat prop!







Problems so far:

1. The maxijet does spin either way on startup, so its a 50/50 chance as to whether it'll spin the right way. My pond pump has a small ratchet inside that I assume is there to stop this, so thinking along the same lines.

2. The propellor comes with a threaded bronze insert that is not removable (already destroyed one trying). However, once you've screwed into the brass, there's about 0.25mm exposed so not sure if this will cause a contamination problem. I could always seal with glue or something.

3. This is going to need a good casing as the propellor spinning is far more damaging then an impellor - it'll slice quite nicely!

All suggestions welcome for any of the above.

Now, if I can do it, surely the guys at Maxijet can (are you listening?). That way, we'd all get a stream for 20 quid (30 dollars)! I'm going to email them this post anyway I think.

Tim


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