The cyclone

Post date: Jan 28, 2013 2:34:28 AM

The purpose of the cyclone is to remove as much ash and other particles from the wood gas as possible. It needs to be sized to match the air flow of the engine it will be used with. A big engine needs a big cyclone and a small engine like the 7 to 10 HP engine we plan to use needs a small cyclone. Ours is 4" in diameter and 16" tall. This design is based on information from several sources. 

Basic dimensions

 This was the starting point for both the sizing and proportions for the cyclone.It is from information on pages 183-188 from the government document on gasifiers from 1981 available at The title is State of the Art Report for Small Scale Gas Producer - Engine Systems. 

Modification for dust collection

Bill Pentz has built and tested cyclones for wood dust collection and made many changes to make his cyclone work better at getting fine particles out of the air stream. His web pages are fascinating

Now at

His modifications made for smaller units that use less power to operate and do a better job of removing particles than any of the major manufactures. Some of his changes have been added to many other commercial dust collectors. I have added some to our design hoping to make a better cyclone.

Thanks to the woodgas group on yahoo for guiding me away from the too large cyclone I was going to make and referring me to the appropriate size for our engines.

The parts for this cyclone were cut out using the CNC plasma cutter at the Prairie Farm High School Tech Ed room. Thanks to the school for letting us use the machine and opening the shop to the community through their Community Education program.

Thanks to Wayne Ayers for doing the very nice TIG welding job on this cyclone and the cooler/filter unit.

Assembled and Drawing

Here is the assembled cyclone and the drawing we used for dimensions.