Reid Harvey on tue 19 oct 99
Here in Cote d'Ivoire I have opted for the rotating cylynder screen,
since this seems to me more like appropriate technology. I recently had
a cylinder made by a carpenter, 45 cms. dia by 100 cms. long. I am
anticipating that an advantage will be that one can see the material
tumbling inside the cylinder, eliminating the need for calculations in
timing a motor.
We screwed inside a backing of 4 mesh screen which will remain in place,
the desired mesh to be fastened down over this. Getting in and out of
the cylinder with material is an easy matter, since the ends are covered
with hinged doors. Structural support at the ends is outside the 45 cms.
diameter. ie each end has a wooden hoop, 45 cms. to 60 cms. A single 2.5
x 10.0 cm. plank crosses each end in order to get to the centers and
allow rotation.
Another advantage of this arrangement is that small batches can be done.
After placing a 45 cm. circle of wood inside this is placed at whatever
length accomadates the width of a small screen. The circle of wood is
then screwed down to the 4 mesh screen, and if the small screen is not
as long as the diameter of the cylinder, any shortfall can be covered
with plastic. Admittedly this is rather crude, but in this part of the
world we have to get by as best we can.
Reid Harvey
Ceramiques d'Afrique
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