[Gasification] Teardrop Chunker

[Tom Miles]

Jeff, Paul,

We've mentioned the USFS work on chunkers on this list before. It began at
the USFS North Central Research Station in Houghton, Michigan, in the 1970s
with development of a chunkwood device to make particles from low quality
trees and forest residues. It was also used for fuel for boilers and
gasifiers. Several studies were done on chunking and drying. The result at
that time was a spiral cutter similar to the Laimet Chipper sold in Finland.
http://www.laimet.com/eng/chippers.html 

As far as I know the Laimet is still the only commercial spiral chunker
sold. The engine or pto driven Laimet shears off a chunk that is used by
some of the Finns on this list for downdraft gasifiers of the Imbert type. I
don't know if any are being uses for open core or stratified downdraft
gasifiers. See:
http://gasifiers.bioenergylists.org/?q=en/ekfiwoodgas
http://www.woodgas.fi/
http://www.ekoautoilijat.fi/tekstit/kalustoesittely.htm

The link Jeff provided reports further development work by Joseph Sturos in
1989. By that time there was interest in making a device to make particles
for flakeboard, oriented strandboard (OSB) and other engineered wood
products. See Radcliffe, Robert C., 1990, "Reducing particle dimensions of
chunkwood." Research Paper NC-296. St. Paul, MN: U.S. Dept. of Agriculture,
Forest Service, North Central Forest Experiment Station RP-NC-296
http://www.treesearch.fs.fed.us/pubs/10779

I think the chunk wood equipment development was largely abandoned after
that.

In a 2006 ASABE paper Naimi, Womac and Narayan reported on three versions of
wood chunkers. "They are spiral-head wood chunker, involuted disk chunker
and a double involuted disk chunker. In comparison with wood chippers, the
average size of ground material from wood chunkers is bigger than grinders.
Chunk wood is defined as short, thick pieces of wood where the majority of
particles have a relatively uniform length of 50-250 mm in the grain
direction and a variable cross-section area, ranging from about finger size
up to the diameter of the material reduced (Hakkila 1989)." They quote Penti
Hakkila 1989. Utilization of Residual Forest Biomass. Heidelberg, Berlin:
Springer-Verlag. The spiral head is the Laimet. And the the involuted disk
is the USFS chunker.

The commercial versions of these chunkers are $30,000 to $40,000. The USFS
prototype chunker would cost about $300,000 today.  
 
Tom Miles
 

     

-----Original Message-----
From: gasification-bounces at listserv.repp.org
[mailto:gasification-bounces at listserv.repp.org] On Behalf Of Jeff Davis
Sent: Sunday, April 01, 2007 4:37 PM
To: gasification at listserv.repp.org
Subject: Re: [Gasification] Teardrop Chunker

Dear Paul and All,

My understanding is that it is a prototype. Maybe a small version (one inch)

for T-LUD stoves? Hand or foot crank?

The below quote from the document bothers me somewhat:

"To eliminate the problem of uncontrolled cutting that occurs after the end
of 
the log leaves the feed mechanism, the feed was stopped before the end of
the 
log passed through, Therefore, about 2 feet of the log was not chunked for 
each test."

If you see Dr Karve, in India, tell him I said Hi.


Jeff



Paul wrote:
> Jeff,
>
> Yes, it is interesting.  Where can we get one?  (I am still on my India
> trip, so
> search from here on borrowed computer is not too easy.)
>
> Paul

-- 
Jeff Davis
Somewhere 20 miles south of Lake Erie, USA

_______________________________________________
Gasification mailing list
Gasification at listserv.repp.org
http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org
http://gasifiers.bioenergylists.org