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The warmth allows a
higher saturation moisture level and therefore to transport more
moisture to the coils on which it condenses and is drained away.
The process is
reasonably controlled and uses little electricity, but it is
slow. The process is also “reactive” in that should the surface
moisture level reduce quicker than expected a higher moisture
gradient within the timber may result and damage the timber. The
gradient is the all-important aspect and the rule of thumb we
work to is to avoid anything more than 4% between surface and
centre. If a higher gradient is detected the dehumidification
cycle can be switched off as the moisture in the timber is given
the chance to migrate to the surface otherwise distortion can
result.
More control can be employed with
Heat-Vent kilns and the heat introduced can come from various
sources which might offer efficiencies otherwise lost. The
process is quicker than with dehumidification and more control
can be exercised.
On completion of the planned new building
at Lochcarron we will set up a heat-vent kiln and are in the
process of investigating using the sawdust and scrap timber from
milling to provide
the heat in an environmentally friendly and efficient fashion.
Vacuum kilns are another option and offer
fast drying with low degrade but are more expensive to set up. |
