[Gasification] cyclone design innovations and building instructions

[jim mason]

many of the gasifier books have designs for "high efficiency" cyclones.  on
further reading, i'm learning that these types of cyclone designs are
descendants of ag cyclones optimized for grain/chaff separation.

the goal in ag cyclones was to have the air/material make one complete
rotation around the top cylinder and crash back into the income air stream.
the created turbulence would help to break apart the grain/chaff, then
further circles around the cylinder and cone would drop the heavy to the
bottom bin and the light would go out the top.

most woodworking cyclones are copied from this design, which was fine when
the fine dust in the outlet was vented to outside atmosphere.  but when
scaled down versions of these are used in home wood shops, with inside bldg
fine filtering, the results are unimpressive.  thus has followed much work
in the small scale woodworking cyclone world to redesign cyclones to NOT
create the turbulence that was originally helpful in their ag and commercial
wood working uses.

cyclones for use in gasification have similar requirements for ALL dust
separation, so we might benefit from noting some of the new work in the
woodworking dust collection world.

the main developments seem as follows:

1. make the air inlet angled downward, so that once the air has made its
first trip around the top cylinder, it is below the incoming air, preventing
the collision and turbulence in the original design.

2. adding an "air dam" spiraling downward, to ensure separation between the
incoming and spinning air inside the cylinder.

3. adding a long straight pipe before the cyclone, at the same angle of the
air inlet, to establish smooth flow before cyclone.

4.  using cone lengths of 3D or 1.64D, not the common 2D or 2.5D that i see
in the gasification books.


there is a good video that shows these ideas in action at:
http://www.clearvuecyclones.com/Order_Page.htm.  this is a manufacturer that
builds clear versions of a cyclone design developed by the "tom reed" of the
dust collection world.  his name is bill pentz.  note the 6" cyclone version
towards the bottom of this page, which has a video.  a 6" cyclone
corresponds to the common 2.5" shop vac inlet feed.  or around 200cuin
engine at rated power.  a 350 v-8 usually runs an 8" i believe.

the originator of this design has a site of pages and pages of tedious
(though very interesting detail). see here:
http://billpentz.com/woodworking/cyclone/Index.cfm

bill also handily provides a long "how to" section on building these.  see
here:  http://billpentz.com/woodworking/cyclone/BuildCyclone.cfm.

there is also a "how to" on this design at:
http://www.studio1304.com/silca/cyclone/index.htm

the cyclone always seems to me the most difficult part to build for a full
gasifier system.  cones are much more difficult than cylinders.  circle to
square pipe transitions are hard.  and making a side mounted inlet port
attachment is non-obvious.  so i was very happy to find these how to's.

jim