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LEGO models my own creation MOCpages toys shop Centrifugal waterpump, a simple electric high volume pump.Technic
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Centrifugal waterpump, a simple electric high volume pump.
A centrifugal pump is a rotodynamic pump that uses a rotating impeller.
About this creation
Pump of this type is known to me. Since impeller of centrifugal pump is a
specific shape, lego has really little to offer.
But I had some older type gears, red g9, blue g15 and yellow g21
( Technic gear Expert Builder xx Tooth with axle hole ).

So I just gave a try with these and they did throw water around.
I built a casing around two g15 gears, some piping and an electric motor to power it.

First tests show that it does work, but I got water all around table!!
Lego bricks have some 0,1mm gaps and that is enough for water to leak.
First protos leaked as much they pumped! The secret is to use fewer and bigger bricks
to minimize gaps. And tape to cover some worst leaks.

First protos had impeller in vertical position, but it wasn't a good idea.
I turned it to horizontal position, so pump can stand in the water and leaking is
no problem anymore.

I used an old 9V motor type ( 2838c01 ) because it can rotate fast enough. I had to gear it a little bit down to get more torque and thus more pumping power. The Current
version can pump to the height of 11 bricks about 4 litres/minute. It pumps water
up to 20 brick height, but max practical height is about 15.
By adding a second motor it gets more power but gears make it noisy.

With this you can make a realistic lego river/waterfall ;)

Water lubricated gears, that little pneumatic hose feeds water back

Water intake. Could be bigger, still searching the best shape.

Pump inside. The gears simply throws water down right to discharge pipe

Twin-motor test. It rews faster, but pumps only a little bit more. Probably discharge pipe should be also wider and intake too. The Train speed regulator I use has 6 speeds
and 5. speed gives already full flow.

Another twin-motor test. Original motor + direct drive motor.
But,I discovered that water intake was a problem. There is only 1 brick distance from
pump intake to the bottom. I increased it to 2 bricks and it doubled the flow !!
This one pumps to height of 21 bricks 2,6 liters/min !!
I retested the original pump and now it pumps 4,5 liters/min !!
Tuning this pump is an endless job ;)

A LDD-picture of another pump model.
This model uses 21-tooth gears. chamber is made of 2339 and 30099 bricks and it's
perfectly round. Gap between gears and chamber is about 2mm, should be very tight.
Not tested in real life yet, but I expect this to be very good pump.

First Test: about 4,5L/min to height of 14 bricks !! intake may still be too small.
But these panels, 2 x 2, are leaking terribly, so i have to use tape ;)

Pump model with XL-motor, lot of changes since first proto. Pumps 6,5 liters/min.

And in real life, pumping 6,5 liters/min ( This has now separate page + video )

See how the pump works!

Building instructions
Download building instructions (LEGO Digital Designer)


 I made it 
  August 25, 2013
Quoting General X (aka SuperSpyX) Do you have instructions for the XL motor powered one?
All pumps in LDD-files too, i guess i have to update Download file
 I like it 
  August 24, 2013
Do you have instructions for the XL motor powered one?
 I made it 
  August 5, 2012
Quoting SuperSpy X Wow, just brilliant! You are a genius!
Thanks! It is a very simple creation, but the principle was little bit hard to apply for legos. Luckily i found these old type gears to do the job. And I was surprised myself how well this works ;)
 I like it 
  July 17, 2012
Wow, just brilliant! You are a genius!
 I like it 
  July 17, 2012
Truly Awesome!
 I like it 
  July 17, 2012
Sir, you've won LEGO universe. That's just brilliant!
 I like it 
  March 12, 2012
Absolutely brilliant! I may use this concept for my latest project! I will credit you!
 I like it 
  February 18, 2012
It's very effective. 4 l/m ..... thats quite something for lego. 5/5
 I like it 
  February 18, 2012
Brilliant engineering, I would not have thought it was possible until I saw this. Funny end to the video too : )
  February 15, 2012
Very cool project that is far out of my area of expertise... I wouldn't have thought that this works with Lego - thanks for enlightening me :D
By re465 .
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Added February 15, 2012

LEGO models my own creation MOCpages toys shop Centrifugal waterpump, a simple electric high volume pump.Technic

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