[TheForge] Engineering data

[Ralph Sproul]

Rick, I've built two chip plants and five automatic sawmills in NH.  You
don't move chips with compressed air.  All materials movers are conveyors,
augers, or transition chutes......and the occassional barn cleaner (which is
a series of paddles welded to a chain run thru a trough to catch debris from
under the saw box/carriage areas).

Hi volume blowers are used to load sawdust, chips and shavings - thru spiral
pipe with deflector shields where the material strikes or it will remove the
front of the trailer it's loading from abrasion.  I'm talking a 12-14"
intake on a 24+" blower moving at 3600 rpm.  This is the only air handling
equipment I've seen in sawmills or wood plants around here.

Use of compressed air in north country would be suicidal.........chips,
sawdust and anything and everything containing moisture freezes and clumps
together and will break chains and conveyors never mind trying to thaw air
in volume that you could not apply enough air dryers to keep the mositure
out of it.

I'd think of a mechanical method of moving material rather than air if you
have freezing temperatures in the area this will be installed.

I have also built a cement silo storage facility one year.  It had the
"pneumatic chutes" from the tanks to the loading boot on top of the trialers
to make the fine powdered material "dance" along above the belting that the
air is supplied below from.  There were compressors the size of running jack
hammers to supply the volume of air needed to make this powder transfer thru
these air chutes.  Wood chips would be much more unpredictable in supporting
and moving.........clogging of a main feed chute is the fastest way to put a
place out of business that you can possibly manage.........don't build
something that does that or the owner/customer will never want to see your
face again.

Ralph

----- Original Message -----
From: "Ries Niemi" <rniemi at fidalgo.net>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Friday, February 18, 2005 10:35 PM
Subject: Re: [TheForge] Engineering data


>
> On Friday, February 18, 2005, at 12:48 PM, Rick wrote:
>
> > Hello all -
> >
> >    Does anyone know where I can find some solid engineernig data on
> > the web for designing a pneumatic conveying system for wood chips?  I
> > have spent some time and am not finding numbers, only innuendo and
> > site-specific stuff. I need to design a system that will move a
> > certain amount of wood per hour and use the least power doing it.
> >
> >
>
> All the straight air powered systems I have seen are only good for
> dust, not chips. Takes a lot of muscle to move much volume in even
> something as light as chips.
> What you are talking about is unusual enough that I really doubt there
> is free info on exactly how to do it just sitting around. You need to
> talk to engineers who have designed systems like this before.
> But you could start out trying to pick their brains for free- I would
> start by calling, not emailing, the companies that make commercial
> systems for wood chip movement- start with the obvious ones that sell
> stuff for cabinet shops, but what you really want to find is the guys
> who build the custom systems for small sawmills.
> Phone calls, and persistance, is the way to go on this- you just dont
> take no for an answer, you keep asking, if you dont make this, do you
> know who does? And ask to talk to tech staff, applications engineers,
> and designers, not salespeople.
>
> If you type "wood chip conveyor systems" into google, you get a whole
> bunch of places to start your search with.
>
> ries
>
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