Patentes

d9) United States
(12) Patent Application Publication no Pub. No.: US 2009/0158615 Al
Muehlboeck (43) Pub. Date: Jun. 25,2009
(54) METHOD FOR DRYING WOOD COMBINED
INTO STACKS
(76) Inventor: Kurt Muehlboeck, Ebcrschwang
(AT)
Correspondence Address:
COLLARD & ROE, P.C.
1077 NORTHERN BOULEVARD
ROSIAN, NY 11576 (US)
(21) Appl.No.: 12/226,243
(22) PCT Filed: Mar. 23, 2007
(86)PCT No.: PCT/AT2007/000141
§ 371 (c)(1),
(2), (4) Date: Oct. 21, 2008
(30) Foreign Application Priority Data
Apr. 12, 2006 (AT).................................. A 629/2006
Publication Classification
(51) Int. CI.
F26B 3/02 (2006.01)
(52) U.S. CI........................................................... 34/487
(57)

ABSTRACT
A method is described for drying wood combinedinto stacks
(2) with the aid of a drying gas stream which flows through the
wood stacks (2), which, by removing moist w aste gas (8) after
the wood stacks (2) and supplying fresh gas (9) before the
wood stacks (2), is passed through the wood stacks (2) par-
tially in circulation, wherein the wood is dried more rapidly
with a moisture content above the fibre saturation than with a
moisturecontent below the Fibre saturation. In order to pro-
vide advantageous, economical drying conditions, it is pro-
posed that before its slower drying with the aid of the drying
gas stream guided partially in circulation, the wood is dried
more rapidly with a drying gas stream consisting substan-
tially only of fresh gas.

METHOD FOR DRYING WOOD COMBINED
INTO STACKS
1. FIHLD OF THE INVENTION100011 The present invention relates to a method for drying
wood stored in stacks with the aid of a drying gas stream
which flows through the wood stacks, which, by removing
moist waste gas after the wood stacks and supplying fresh gas
before the wood stacks, is passed through the wood stacks
partially in circulation, wherein the wood is dried more rap-
idly when it has a moismrc contentabove the fibre saturation
than when it has a moisture content below the fibre saturation.
2. DESCRIPTION OF THE PRIOR ART
[0002] For drying wood stored in stacks, a drying gas
stream is usually conveyed through the wood stacks, wherein
moisture is released from the wood surface to the drying gas
and specifically as a function of the gas temperature, the gas
humidity and the How rate of thedrying gas. In this case, the
dry ing gas. usually drying air. is passed through the wood
stacks partially in circulation, wherein a partial stream is
separated from the circulation for removing the moisture and
is replaced by heated fresh gas. The moisture of the drying gas
supplied to the wood stacks as a function of the residual
moisture of the wood for the desired drying profile can bepredetermined by means of the amount of moist waste gas
removed and the supplied drier fresh gas. With regard to the
shortest possible drying time, a comparatively high How rate
is selected for the drying gas steam which results in an appre-
ciable energy input.
[0003] The fact that the drying rate of wood having a mois-
ture content above the fibre saturation, i.e. wood having a free
waterfraction, substantially only depends on the amount of
heat supplied and only depends on the moisture content when
the moisture content is below the fibre saturation, i.e. when
water is only bound in the wood cell walls, has had the result
(AT 412 741 B) that wood stacks having, a different average
initial moisture above the fibre saturation are dried as far as
fibre saturation at differentspeeds so that as a result of the
associated different drying rates, despite the different initial
moisture, all the wood stacks simultaneously reach fibre satu-
ration and consequently can be dried together to the desired
final moisture below fibre saturation and specifically taking
into account a considerably slower dry ing process which is
advantageous for this purpose. In order to ensure...