Wood Dring Method(3)
There are many ways to dry wood, how many do you know? There are Solar drying, Vacuum drying, microwave drying, high-frequency drying and so on.
Both high-frequency drying and microwave drying use wet wood as the dielectric. Under the action of the alternating electromagnetic field, the water molecules in the wood rotate at high speed and frequently, and the friction between the water molecules generates heat, so that the wood is heated from the inside to the outside at the same time. dry. The characteristics of these two drying methods are fast drying speed, uniform temperature field in the wood, small residual stress, and good drying quality. The difference between high frequency and microwave drying is that the former has a low frequency, a long wavelength, and a deep penetration depth to wood, which is suitable for drying thick wood with large sections. The frequency of microwave drying is higher than that of high frequency (also known as ultra-high frequency) but the wavelength is shorter, and its drying efficiency is faster than that of high frequency, but the penetration depth of wood is not as deep as that of high frequency drying.
The advantages of high frequency and microwave drying are that the drying speed is very fast, usually dozens or even hundreds of times faster than conventional drying, followed by uniform temperature in the wood, low drying stress and good quality. However, the disadvantages of these two drying methods are large investment and high power consumption. At the same time, if the power selection is different, the power is too large or the drying process is not properly controlled, which is prone to internal cracking and carbonization. In addition, microwave drying is not ideal for drying wood with large thickness or high moisture content.
Because microwave and high-frequency drying have outstanding advantages in solving the drying of large-section pith core, and microwave and high-frequency drying equipment has been relatively complete, the drying process has gradually matured, and its industrial application is similar to that of vacuum drying. Usually vacuum-microwave, vacuum-high frequency combined drying.
In addition to this, there is the wax cooking process that has caused widespread controversy in the rosewood industry. To be precise, the wax cooking process is a drying process but not exactly a drying process. It is a process technology to stabilize the wood property and prevent cracking in the drying process of wood. Not every kind of wood needs to cook paraffin wax. The paraffin troughs are different, which can dry the wood. However, because the thickness and density of the dried wood are different, the required troughs are different, so the cost during use may be high. Some. It is currently rarely used in the field of solid wood, because the technical difficulty is relatively high, and it is still being continuously improved.
