DIY "Stream" Style Pump

I have seen and in fact have powerheads with snail shaped impeller chambers and an offset outlet, the impellor is curved too. Something is happening that we are missing, perhaps the coils are half volt and a bit of rectification is going off, or maybe on the more expensive stuff a chip is installed to hit the no volt/rising volt turn on. I just know that not all powerheads turn both ways (but most do) :)
 
They have a brake installed on the shaft, and once that has been engaged, the propeller will pause until the magnets rotate it the other way. Wierd, but works.
 
Good answer Melev, I know cos I use Tunze stuff, but could this effect be replicated electricly? For instance if you wired a 110volt pump to a 220volt supply with full wave rectification (NO smoothing) you would only get a waveform that went either up or down and at the same potential and frequency - all it would take is a couple of diodes would it not? I.E. What I am trying to say is that you would know that the impulse to turn the motor would be guaranteed.
 
Earlier in this thread, someone built a little foot in the cover-area, and if the impellar hit it, it would stop and reverse to flow the right way.
 
I think that this needs some thought - Given that AC current is in your case 55 volt above ground+ then 55 below ground- it seems that whenever your particular pump "catches" the waveform depends on which way it will rotate. We need a way to either determine when then pump switches on or to control the waveform of the supply. Many years ago I built a chip and triac supply that would only switch at zero, however I am at a loss to find something that wil guarantee switching at a rising or falling voltage.
 
Just got done looking through all the pictures and the videos. I dont have an MJ but was wondering if an aquaclear 302 or 402 could be used to do this?

Has anyone done it before?

Thanks
Kris
 
Just wanted to report a failure. I was rather sloppy on the way I aligned the impellor on one of mine. It leaned a little bit to the side. Well after awhile the blue plastic covering that's rubbing up against the side gets worn away. The magnets then get exposed to saltwater. A little corrosion later, and well - into the trash. Big ole puffy rust spot.

So just make sure your impellors are as centered as you can make them, or they only last a year!

PS: I use Penguinââ"šÂ¬Ã¢"žÂ¢s cause a local LFS sells them, and doesnââ"šÂ¬Ã¢"žÂ¢t sell MaxiJets.
 
So once I'm able to maneuver it so that the propellor is facing the way I want it any powerhead will basically work. I want to try my hand at this.

-Kris
 
Impulsed by this thread, I started to make one myself. In my mod, I don't use any glue, just make sure everything is tight fit all together. Pics explains it all. The good thing, I can change it back to original state of MJ if I don't like this mod.

I mostly use hack saw with thick blade to fabricate the housing, variuos grinding tools to make the cap. Make sure you don't break the L-shape holding peices on MJ body when putting on the housing.

mj_mod.jpg


mj_mod_01.jpg


mj_mod_02.jpg


mj_mod_03.jpg
 
Here's my shot at the mod. The goal was to make one that was compact, powerful, and required no permanent changes to the powerhead.

Parts:
316 Stainless 3/32" Rod - 3 5/8" Long (Small Parts #ZRXX-015-24)
Papermate Pen Tube - 1 3/8" Long
Dumas 1 3/4" Propeller 1/8" Hole (Tower Hobbies #DUMB1860)
1 1/2" Diameter PVC Pipe - 1 1/2" Long
Small Piece of Acrylic

Steps:

1) The Papermate Pen Tube is notched with a 3/32" wide x 7x16" long slot to fit in the MJ's magnet assembly. This should simulate the "hammer effect" that the original impeller has to help guarantee the prop always starts.

2) The Propeller was trimmed to 1 1/2".

3) The Papermate Pen Tube is attached to the propeller with JB Weld.

4) The PVC was machined to fit the MJ's mounting with a circular saw. (Take careful measurements and make a jig! It's *much* easier that way.) Six 1/2" holes were drilled at 1" increments around the perimeter of the pipe, centered 1" from the front of the pipe.

5) A piece of acrylic was cut to provide a small cover to the front of the unit and to keep the SS rod centered during use.

Does it work? You bet'ja!

All the parts laid out for you to see:
all_parts.jpg


Close-up of magnet & prop assembly:
mag_prop_closeup.jpg


Completed prop assembly:
prop_assembly.jpg


Completed Unit:
complete_front.jpg
 
I am finished making one (well sorta, I just need to fit the propeller on.

But I didnt use a MJ I used a jebo pump. (it's 98 GPH w/o any mods)
 
dcoufal, Why does your impeller look diff than my 1200 MJ impeller? The way you have the prop attached to the mag is cool it allows alittle play when it starts up correct? I bet that helps it its loose like the impeller.

The only problem I see is the acrylic on the front. Everytime i used a piece of acrylic it would wear out and break every few weeks.
 
I don't believe that the acrylic is a problem, but not having the bushing in the front will create that excess friction and I think that is where the real problem lies. I think the best thing is to make sure the bushings are still used.
 
niko5 said:
dcoufal, Why does your impeller look diff than my 1200 MJ impeller? The way you have the prop attached to the mag is cool it allows alittle play when it starts up correct? I bet that helps it its loose like the impeller.

The only problem I see is the acrylic on the front. Everytime i used a piece of acrylic it would wear out and break every few weeks.

It looks different because I was using an *old* MJ 500 for testing. I noticed the new MJ 1200's don't have the same type of impeller....

Anyway, after testing for a while it became obvious that the "non-permanent" version is *extremely* noisy! So, I used a little JB weld to make it all permanent and it now produces less noise than the real impeller does!

The acrylic shouldn't wear.... see my next response to ReefWerkes comment.

Dwain
 
ReefWerkes said:
I don't believe that the acrylic is a problem, but not having the bushing in the front will create that excess friction and I think that is where the real problem lies. I think the best thing is to make sure the bushings are still used.

Maybe it's the way I'm making mine.... but, my stainless rod doesn't spin. It doesn't need to spin - the magnet and prop assembly are the only pieces that need to spin.

Kind of like the Hagen powerheads - the rod in their units is stationary and is for centering purposes only. Same on my Maxi-Jet mods.

Since the rod doesn't spin, there's no wear on the front piece of acrylic.

And, before you say the friction between the rod and the magnet will reduce flow, see my last paragraph below; or, use a smaller 316 SS rod and cover it with shrink PTFE. That'll really reduce the friction!

I played with it in my 125gal freshwater this weekend and it was moving deitrius violently on the opposite end of the tank - and, that was with a MJ 500.... I checked with a watt-meter and it was only showing 6 watts. I plan to use MJ 900's in my final / live version.

Dwain
 
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