Microwave Vacuum drying chamber with 12-24 hour cycle, devoid of many drawbacks of convective and vacuum technology, is designed for dehydration of large-size timber of any kind. Most often used in the production of wooden log houses, intended for residential construction. In the design of the chamber enters a frame-cylinder fixed in a frame with waveguides for supplying energy-microwave generated by a microwave generator (with 2 stages) and condensate outlets by means of a compressor. The sections connected to the cylinder of the horizontal housing rotate from the drive unit and are supported by rollers. They are equipped with external covers, through which a load of sawn timber is produced, and have lashing straps. The design allows improving the quality of output, the productivity of the process, reducing the time indices.
Description of work:
The use of microwave for dehydration of wood is very promising. Microwave wave energy causes rapid heating inside timber, accompanied by an excessive growth of internal vapor pressure. There is a simultaneous diffusion of vapor molecules and its movement through the capillary system and the pores of the tree. The process of moisture withdrawal becomes more intense.
The microwave oven operates autonomously. Operating Voltage 380 Volts. The magnetron is cooled by air, using modular aggregates. The supplied air heated to the drying temperature is used to remove water vapor from the chamber. Heating is necessary to increase the ability of the air to absorb moisture and prevent the wood from cooling by air currents. Such a device ensures the removal of almost all moisture (about 90 percent) in liquid form, thus reducing the amount of energy needed for drying.
The ultrahigh frequency field produces a uniform effect on the wood, heating it with an intensity proportional to the amount of moisture it contains. The process of moisture withdrawal expands on the structure of the timber itself and its internal pressure. In the case of vacuum, the boiling point depends directly on the pressure.
The device works as follows:
Through the open covers of sections in the container's capacity, the trolley is rolled in bundles of logs. Closing the outer covers and turning on the first stage of the magnetron, the waveguides supply the energy of the microwave field to the portion of the raw material inside the shell. The liquid condensate that is released during heating is discharged outward along the branch pipes. This is the first stage of drying in microwave mode. When the moisture content of the material reaches the 30% level, the 2nd stage of the magnetron starts, at which the wood warms up and the vacuum compressor is turned on. As a result of complex vacuum and microwave exposure, the tree is dehydrated to the required level, without the risk of charring.