To achieve fast and high-quality lumber drying , the most the best use of the combined drying technology , where all the advantages of each technology dryers were connected . Microwave energy heating wood vacuum at low temperatures , especially moisture withdrawal from deep pores . These cameras are applicable to all type of wood , with high performance and without defect conventional convection and vacuum drying . The drying cycle is 12-24 hours (soft wood ) , 36-48 hours (hardwoods ) using the timber and woodworking industry for drying lumber and building rounded logs , profiled timber and also for drying materials in the production of houses . To avoid damaging the tree structure , you need to apply a combined drying technology - microwave + vacuum . All of our drying ovens are designed according to customer requirements . Therefore , we have already established a large number of microwave vacua drying chambers . The use of these devices provides improved performance , high-quality timber drying and reducing drying time
The advantages of vacuum chambers can be fully realised through the use of microwave energy. With microwave drying , dehydration is an active timber as a result of the impact of electromagnetic radiation on free to contact moisture. This phenomenon leads to several times more effective drying of the wood and reduces energy consumption significantly, since not required for warming the wood structure and the ambient air (coolant ), while most of the energy is absorbed by the moisture inside the timber itself. Produce to heat expended on heating the raw wood to the boiling point of water and moisture evaporation. Since the moisture inside the timber is in a closed space, with the beginning of the boiling water rises inside the over pressure timber. When the microwave drying of wood is a motor over pressure moisture from the inner layers of the wood surface. And most importantly, the two main gradient - pressure and temperature - are constantly directed towards the centre of the wood's surface. A moisture gradient throughout the volume of wood is close to zero , which prevents the formation of stresses in the timber during the drying process. Using the microwave for drying wood showed a real and tangible acceleration of the drying process and improve the quality of dried lumber
Fundamentals of thermodynamic vacuum drying. At the interface between two liquid-vapors phase, there are an equilibrium flow processes of evaporation and condensation. Evaporation is the process of converting the liquid into vapour at a rate exceeding the rate of the reverse phenomenon - condensation. In both cases the heat exchanged associated with absorption or release of heat of a phase transition changes the physical state of matter : during evaporation heat is absorbed and released by condensation. Condensation occurs to contact with the surface of saturated steam at a temperature below the saturation temperature. If the surface temperature exceeds a saturation temperature, no condensation occurs. There are two types of condensation : film and dropping. The condensation of liquid condensate films surface wets and forms a continuous film thereon, which has a great resistance to heat to flow. In the case of dropwise condensation vapour condenses on the cooling surface in the centres of condensation in the form of droplets. They are not completely wetter the entire surface, and only grow by the condensation of steam in them and fusing them with others located nearby drops. They increase as long as the action of gravity or other forces will not break away from the surface and will drain through it. Dry and wet areas on the surface of the alternate, and it gets kind of spotty. When condensation drips the highest intensity of heat. To initiate the formation of droplet's of the cooling surface is treated with a thin layer of material which has extremely low wettability with liquid. Thus, the vacuum drying occurs to two-phase liquid-vapor transfers and vapor-liquid.