There are several mainstream methods for wood drying, air drying, conventional steam dry kiln, vacuum kiln, and high-frequency heating vacuum kiln and etc. Because of fast-drying and high-quality drying results, the high-frequency heating vacuum is more and more popular in the wood industry. so what’s the difference between a high-frequency heating vacuum kiln and another vacuum kiln?
The vacuum principle is the same, both of them are to lower the boiling point of water and make the wood-heated at low temperature. The main difference is the heatin g principle. Another vacuum kiln is to use heat plates. Each of pcs wood is sandwiched by heated plates (the plates filled with hot water or oil) The heated plates transfer heating from the surface to the core of the wood. This way is no problem for thin lumber, if, for the thick wood, it will be better to use high-frequency heating vacuum kiln, the high frequency or radio frequency is kind of direct heating. The principle is using wood as a medium, a capacitor is a group between two pieces of metal plate, after give them voltage, the electric field produced. The water molecules between electrodes will be polarized by alternating magnetic fields and move at very high speed rapidly. The impact and friction (billions of times per second) among water molecules created heating in a very short time.
So the conventional steam kiln or common vacuum kiln is uses heating transfer to dry the wood from outside to the inside of the wood. high-frequency heating is let wood moisture heated itself, this continuous effect lets the whole wood-heated surface to the core wholly and uniformly. That is also one of the reasons why high-frequency vacuum wood dryer is faster than other wood dry kilns
