Cheap static Mixer ideas.

My favourite methods introduce no backpressure, are simple, cheap and effective.

1. The Brush mixer
Arrange the outlet of your pump to fire directly, end on, down into the bristles of a large brush.

Choose a brush or broom-head with densely packed long stiff bristles. Can be stainless or natural bristle. The brush can be mounted inside your reactor, right in line with the jet of biodiesel from the pump.

The bristles will cause the biodiesel to take a complex and intermingling route out of the brush, mixing everything together for you.


2. The chain mixer
Fire the biodiesel down a group of fine-link chains. The links wil cause the biodiesel to curl and mix in a complex pattern. Again, because the chains are outside the tubing, they introduce zero back-pressure.


3. The turbine mixer
A more dynamic method, for the keen metal-basher, is to fire the biodiesel down onto a simple home-fashioned turbine, and have the turbine stir the contents of the tank via a shaft and paddle. The blades of the turbine will divide the flow and splatter it randomly around the tank, and the stirring motion will further help mixing. Again, all achieved without introducing back-pressure.


Here is a simple in-line DIY static mixer suitable for low viscosity fluids such as warm vegoil + methanol & lye.

It consists of a pipe Tee-piece, which has a wad of domestic cleaning stainless steel strip-wire wool pulled thru the horizontal section.

The horizontal section is around 7 inches long in total.

The poorly mixed fluids enter the tee at the top and divert left and right, thru the steel wool, which introduces mixing-turbulence.

The two flows are recombined into another Tee-piece, which also has a wad of steel wool in it.

The pressure drop caused by the steel wool is compensated for, somewhat, by having the flow go thru 2 parallel pipes.

wire wool static mixer

The wool fits nice and snug in the pipes, so your BD mix has to go thru it, not round it. Don't pack it too tightly, though, or you will create too much back pressure.

wire wool static mixer

Just a few ideas to play with, see how you get on.

Hope it helps, good luck.


You can email me at grahamlaming at hotmail dot com

Posted January 27 2006

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