The construction industry is currently undergoing an active stage of technological development, which is reflected in the tools used, and on the methodology for performing repair and installation operations, and, of course, on materials. At the same time, due to accessibility and low cost, traditional materials, including wood, are still in demand. Another thing is that it cannot be used in its pure form, since even solid-state rocks no longer comply with building codes for protective properties. This barrier can be overcome by special preparation operations, including drying of wood in drying chambers - a technology that improves a whole range of technical and physical parameters of the material.
Chamber Drying Technology
The principle of drying in vacuum chambers is based on the laws of evaporation and water circulation. That is, the main tasks of the method are reduced to ensuring optimal fast removal of moisture from the structure of the tree, but without negative consequences for performance. The technology under consideration is oriented towards the implementation of this process. In practice, it is performed using special installations that circulate water through the wood structure in the direction from the core to the outside. Next, water is removed from the surface by evaporation. But it is important to understand that getting rid of moisture is not the only task that wood drying in drying chambers implements. The technology also allows you to eliminate physical defects, but for this additional equipment like presses is used. As for the technical implementation of the process, it is usually performed by manually loading the material into the appropriate chamber. Further, due to the heating plates, the unit performs automatic heating against the background of intense evaporation.
Features of the vacuum drying method
Compared to traditional drying chambers, the new technology of cylindrical vacuum drying allows to achieve a high process speed. This is due not so much to the principle of impact on the material, but to the loading mechanics and the location of the blanks relative to the functional plates. But the thermal effect has its own characteristics. Since the wood material is compressed between the plates under pressure, a high intensity of impact on the structure is ensured - accordingly, a greater amount of moisture is evaporated. In terms of energy consumption, vacuum drying of wood also has its differences. The technology features in this parameter are determined by an increase in the temperature of the plates and optimization of the physical movement of the material inside the chamber. Therefore, to achieve the same results as drying methods with alternative methods, such chambers spend less energy.
Drying stages
Automated cameras allow without the user to implement a standard set of technological steps, which is as follows:
- Warming up the material. Initial heat treatment, during which the wood structure is prepared for the next steps.
- Directly drying. At this stage, a combined operation of moistening-drying is performed, which allows to soften the material as much as possible in order to further dry out.
- Cooling. In fact, this is the stage of crystallization of the structure, due to which the wood, which has become malleable due to heat treatment, regains its optimal hardness characteristics.
As noted above, all stages of the drying process are controlled by automation, and the operator monitors the performance of the safety indicators. But even before the event, the user is required to set the optimal drying mode. In particular, it sets the pressure and temperature, focusing on the characteristics of the material. For example, for conifers with a thickness of 2.5 cm, a pressure of 500 kg / m2 is required. As for the temperature regime, in this case it can be 80 ° C.
Drying chamber device
Modern cameras are made in the form of a parallelepiped or cylinder. The output side of the structure is provided with a cover through which the operations of loading / unloading material are performed. Moreover, the structure of the cover includes a rubber sheet fixed on a metal frame - this solution allows you to create an almost perfect vacuum with increased sealing. Each layer of lumber is lined with heating plates, which are usually made of heat-conducting aluminum alloys. To carry out movements, the plates are equipped with roller mechanisms. Thanks to the movement of the heaters, balanced drying of the wood in the drying chambers is ensured. The manufacturing technology of the chambers also provides for the connection of circuits with circulating water. Liquid boilers are placed separately and provide for their own heating. For stable vacuum maintenance, a special pump is placed inside the chamber.
Hydraulic press application
It has already been said above that in the process of passing through the drying stages, the structure of the wood softens and becomes pliable. This condition is in the framework of the drying process is secondary and excessive. Actually, to eliminate these consequences, the final cooling stage is provided. However, the softened structure of the material can be exposed to a hydraulic press, which will relieve the workpiece from physical defects - at least ensure its straightening. Such presses are introduced into the general complex of capacities at which wood is dried in drying chambers. Pressing technology, in turn, eliminates possible defects that were acquired by the material in the chamber. The final workpiece will be “correctly” deformed with the parameters that are needed for working lumber.
Drying methods
At the moment of technology development, three main methods of vacuum drying are distinguished. The first two methods have already been considered - this is directly drying and press-vacuum preparation of the material. But there is also a method of steam treatment in a vacuum chamber. Its relevance is due to the possibility of excluding heating plates from the design of the chamber, since hot steam covers the entire space without requiring a special direction of flows to individual sections of the workpieces. This approach provides many advantages that provide steam heating methods for drying wood. Drying chambers, for example, allow you to load not only the laborious manual method, but also using forklift trucks.
What effect does drying provide?
Drying itself as a process of optimizing hygroscopic properties gives wood relatively high strengths. This is already enough to ensure that the material meets the basic requirements of building regulations. But large woodworking plants use the above technologies and methods of drying wood only as a preparatory stage for further processing of the material. In particular, for impregnation, which will additionally give the workpieces the quality of fire resistance, moisture resistance, frost resistance, etc.
DIY drying
To make your own dryer with affordable means, you will first need a separate room. In size, it can correspond to a small utility room or hozblok. It is desirable to carry out the construction of brick or concrete, and insulate and insulate the internal surfaces with layers of foam with a foil coating. As a result, it turns out, though not a vacuum, but a sealed board dryer. How to make heat exposure elements? For this, several convectors or radiators should be provided - their number will be determined by the structural capabilities of the room and the requirements for the drying itself. Heating equipment will provide the effect of evaporation. For greater efficiency, the fan thermal function can be added.
Conclusion
During construction and repair operations, the question often arises of choosing between different materials. Limited financial opportunities often exclude metal alloys and high-strength plastics, leaving a non-alternative version of wood. But in many cases this solution also justifies itself in terms of technical characteristics if a drying chamber for lumber is used. You can’t perform such a camera with your own hands without the cost of expensive radiators, but in the long term, its application will prove worthwhile. As the practice of operating structures based on correctly dried wood shows, the material can serve for years even in harsh conditions without losing its primary properties. Another thing is that a lot will depend on the type of wood that is planned to be used for such purposes.