Board dryer: creating and using a drying chamber. Drying chamber for lumber: how to make it yourself? Types and manufacture of drying chambers Build a drying chamber for wood with your own hands

7 reasons for every craftsman to have his own wood dryer

The better the wood is dried, the better the finished product. Therefore, you spend a lot of money on drying wood. You give only to trusted places and patiently wait for the end of the process. But this stage can be accelerated and made less expensive. And even get 20% more quality material out of it! If you have your own dryer for FlexiHIT boards - our production.

Why do you need a personal FlexiHIT lumber dryer?

• 20% more quality material! The result is flawless wood without deformation, internal stresses, warping and cracks. 15-20% more workpieces than when drying industrially. What is the reason? Drying occurs as naturally as possible. Infrared radiation is as gentle as the rays of the sun. But thanks to a special design and innovative solutions, it dries faster and more evenly.
• From one board to 10 cubes. For the first time in the history of professional drying, you can dry any volume of wood! From one board to large stacks. No more need to lose money on drying or accumulate large volume tree to load. At the same time, the cost of our kit is several times lower than the cost of a drying cabinet.

Material ready in 3-7 days. Assembling a wood dryer takes no more than a day. Installation is simple, thanks to detailed instructions. The drying time depends on the type of wood and the amount of moisture in it. On average - from 3 to 7 days. Drying period for soft wood, the drying time will be from 3 to 7 days to 6 - 8% humidity, for hard wood from 13 to 20 days to 6 - 10% humidity. Stable result - up to 8% humidity in 7 days!

• Automatic drying process. The drying procedure is absolutely comfortable and does not require your participation. After loading the material, the wood dryer is completely autonomous - you do not need to constantly monitor the wood drying process as when drying in an induction dryer. No special place required either! Dry the wood at least open air in the courtyard of the house, even indoors. Anywhere and unattended.

Calculator for calculating the cost of a wood dryer

Wood dryer price:

1. Infrared cassettes: 29,700 rub.

2. Control cassettes: 12900 rub.

3. Control panel: RUB 12,002.

4. Cabling: RUB 8,286.

5. Lathing: 1257.76 rub.

Total: 64,146 rub.

The price calculated by the calculator is approximate, to clarify the price of a wood dryer

4 reasons why you shouldn’t make a dryer yourself

• For a long time. A lot of time will be spent on experimentation, design and construction. It took us 10 years to create the dryer, having behind us other successful developments in the field of infrared heating.
• It's a chore. It will take a lot of time to debug the dryer so that the resulting lumber is of high quality. We have conducted thousands of experiments.
• Risky. You may never be able to create a normal dryer. This is not an easy task, believe us.
• Expensive. There is a possibility that the dried lumber may be spoiled at first, which will lead to even greater financial costs.

FlexiHIT - 3 years of improvements!

• Our wood dryer has been improved for more than 3 years. You don't have to go through this journey on your own. It is enough to assemble the device according to detailed instructions.
• There is a lot of material on the Internet about IR devices created by amateurs - and they assure you that high efficiency process. But there is no convincing evidence.
• We have been doing IR heating for ten years. We manufacture functional equipment for industry, construction, and medicine. We have serious production facilities and professional designers. However, developing the dryer did not come easy to us. A high-quality dryer cannot be created “on your knees”!

How does the FlexiHIT wood dryer work?

As a result of 10 years of testing and development, the board dryer is a set of special thermoactive cassettes with a thickness of 1.5 mm. The cassettes are placed in a stack of lumber prepared for drying in a certain sequence.

Wood drying occurs by heating the wood with infrared rays. This drying method does not require a coolant. Therefore, there is no need to maintain its precise parameters, ventilation and complex automation.

The operating life of the heating cassettes, subject to instructions and careful operation, is at least 3 years, 1-year warranty.

Video of the FlexiHIT dryer and instructions for assembling and drying wood

Comparison of modern wood dryers and drying technologies

Stack fencing

The stack shell consists of polystyrene insulation located under the stack and on its top, as well as a reflective fence covering the perimeter of the stack. The casing is not supplied as a set and can be designed to fit specific stack sizes.

You can also familiarize yourself with (one of the design options).

Examples of correct and incorrect stacking of wood drying cassettes

Do you have any questions about drying lumber at home using a FlexiHIT dryer?

When steaming, moisture evaporates from the middle of the wood. I have no idea how this process occurs when wood is locally heated. I also don't understand why you can do without fans.

Why is it steamed with saturated steam when processing wood? In order to saturate the wood with moisture and dry evenly at a speed at which moisture will migrate from inner layers to external.

When using low-temperature infrared emitters, moisture is already “expelled” from the inner layers, which leads to intensive selection (condensation) of water in the first quarter of the drying process and removal of moisture. No steaming needed.

But in the chambers it is needed, because the coolant is hot air, and it does not penetrate into the wood; it dries slowly, starting from the surface. Therefore, you can’t rush, you need to wait for the water to capillary from the center to the surface.

Both ultrasound, high-frequency frequency, and induction tear wood - it’s clear why. I think that your method should tear no less, but even more. Are you also trying to heat the wood from the inside?

We have a soft mode, this is natural drying, so there will be no tearing. This refers specifically to the rupture of pores, capillaries, non-surface ruptures and cracks that occur due to uneven drying of the board.

Do you have experience organizing a lumber dryer in the basement? What pitfalls might there be? A bath for collecting water is planned under the drying area. The temperature in the basement is above zero.

“Pitfalls” depend on the volume and frequency of drying. We must expect that not all the water condenses - some comes out as steam, and if there is no good ventilation, the basement walls will get wet. With constant operation of the wood dryer, the basement may gradually warm up, and the high temperature outside the stack shell will change the dew point, and condensation may decrease. Ventilation is required if the room is small. Up to 300 liters of water can come out of a cube of pine, 500 from oak.

How to operate a wood dryer winter period? How to control and regulate air humidity? How high is the stress in the material after drying?

Steam collects in the chamber and reaches such a concentration that drying stops and the steam must be removed. Paradox: the chamber is needed to retain air, but it increases humidity. Therefore, wood drying is possible when the following mode is used: “heating the air - ventilation - pumping out moist air - heating again.” And when acting directly on water without a camera, everything works out easier. We use isospan to ensure uniform humidity in the stack and speed up the drying of the wood.

Friends!
Those who deal with wood, process it and use it in any way are forced to deal with the problem of drying it. Drying wood is always relevant and pays off, because “wet” wood is much cheaper, and dry, ready-made wood is very expensive. It is necessary to remove excess moisture from the wood so that the process of uneven evaporation of water and juices does not occur, which is associated with the heterogeneity of the wood structure along the longitudinal and transverse fibers. But damp wood is unsuitable for serious processing, much less for construction, otherwise it will deform, crack, warp, and “lead.” How can you make a wood dryer with your own hands?

How to make a wood dryer with your own hands at home or in the country

If space permits, then it roughly looks like this:

1. First, we free up space in the kitchen near the stove or electric stove, fireplace, etc. You need to carefully calculate and measure how everything will function and look.
2. Partitions are installed from old doors and window frames, other available materials, for tightness everything needs to be adjusted and sealed. The size can be, for example, 2x2 or 3x3, depending on capabilities and needs.
3. Of course you have to leave it entrance doors and vents, and during drying keep them tightly closed so that there are no unnecessary drafts or simply excess air movement. Otherwise, this may lead to a less predictable drying process, loss of control over the process and loss of quality of the output wood.
4. The fenced-off area must be covered with insulation, all cracks must be sealed, plugged, caulked, etc. That is, to seal the space of the future dryer as much as possible to enclose the space and improve the quality of drying.
5. Since there is a high temperature near the stove or heating electrical appliance, then, if necessary, it is better to cover it with bricks that will accumulate heat and release it into a closed room. If the air does not circulate actively enough, a fan should be installed.
6. If you plan to dry a lot of wood or already finished products from it, you need to build strong metal shelves. It is better to secure it with anchors so that it can be loaded with serious weight.
7. To prevent the workpieces from bending, you need to fasten the edges of the material with pins. If the length of the wood is large, then several pairs of pins (3-4) are used. Of course, it is better to use wood of the same species, thickness, size and weight, otherwise drying will be very uneven. Be sure to lay out the material for drying with thin strips, bars, spacers for better ventilation. It is necessary to carefully monitor the uniformity of temperature and air flow, then drying will proceed more smoothly and the quality of the output material will be higher. Moreover, building several dryers is not very good big size more profitable than one larger one.

Do-it-yourself wood dryer, as a separate structure

1. First, a frame is constructed from an aluminum profile; it will not rust, is lightweight and durable.
2. Then it also needs to be sheathed with aluminum sheets, and thermal insulation 10-15 cm thick must be fixed on top. This insulation must be fire-resistant, strong and flexible. Roofing felt should be laid on the floor and sawdust should be poured on top.
3. Next, you need to ensure the tightness of the building and seal all possible outlets for heated air. The tightness of the structure is of great importance for high-quality drying.
4. The boards intended for drying should be laid out in narrow (1-1.5 m) stacks and spacers made of bars should be placed between the rows and boards. And the height of the stack can correspond to the height of the room.
5. Drying can be done using, for example, fan heaters, which should be installed across the air movement. Or choose another drying tool that suits your individual needs and capabilities.

A simple effective way of tubeless infrared drying of wood from 1 board

If you don’t want to build a dryer yourself or you don’t have the opportunity to do this, then you can use a ready-made solution.

There is a relatively recently used method of drying wood using infrared radiation. The process itself is as follows: the wood is heated with infrared rays using a tubeless cassette dryer. What is the design of such a dryer? It consists of several thermoactive cassettes 1.5 mm thick. The cassettes are stacked in a stack of wood prepared for drying, alternating with spacer bars. That is, the coolant is already among the lumber intended for drying. Therefore, there is no need for a separate heat source, ventilation, maintaining precise parameters, or complex electronics and automation. The drying is controlled by a thermostat, which sets the required temperature for individual layers of the stack. For more optimal performance of the drying structure, the stack is covered with a material with a reflective layer so that the condensate drains outside the stack. It is important that the process can proceed as follows: outdoors(preferably under a canopy, to avoid possible precipitation), and indoors.

The advantages of this type of drying are

• ease of maintenance,
• equipment mobility,
• high rates (8% humidity can be achieved).
• high quality of the final material (no warping or internal stress),
• speed (from 3 to 7 days),
• variability, i.e. You can dry individual boards, or even just one, or entire large stacks.

You can watch a video about this technology here:

Drying wood from scrap materials. FlexiHIT.

Drying lumber in a tubeless cassette dryer

So, if you have a constant need for dry wood, then you can build a dryer, it’s not that difficult. Or buy a ready-made one and enjoy the finished dry lumber, which can be used to make various useful and interesting products.

There is not a single woodworking enterprise that can do without the wood drying procedure. To prevent the occurrence of various defects, it is customary to use special technology drying wood in a drying chamber. If you want to produce wood products yourself, you will also need a drying chamber for drying wood. Today we will talk about how to do it correctly.

The need to dry wood

How to dry a board efficiently and quickly? This question has interested every carpenter since ancient times. People have long been engaged in storing wood for many years in order to have time to dry it evenly. The grandfather prepared wood for his grandson, using the very material that his grandfather left him.

The importance of properly dried wood is colossal! For example, if wooden furniture, which is in the room, is made of too wet wood that has just been cut down, then it will dry out over time, because wood can dry out and decrease in size, which means it will deteriorate!

If the door to the house is made of excessively dry wood, it will swell over time and will not be able to close! If the door panel is assembled from blanks that are unevenly dried in volume, then it may burst or warp! Therefore, it is recommended to dry all wood blanks. In addition, drying protects the material from damage by wood-destroying fungi, prevents the size and shape of wood, and improves the physical and mechanical properties of wood.

Drying wood is a lengthy, complex and expensive procedure. Using traditional technologies, wood is heated with superheated steam or hot air. Dried wood can be transported and stored longer. In addition, during operation it does not deform. The boards are dried in steam chambers, where the possibility of internal damage is excluded.

Wood moisture concept

To fully understand the essence of the drying process, it’s worth diving a little into the theory. The procedure for removing moisture from wood is not entirely simple, because there are two types of moisture in the material itself. Wood consists of plant cells elongated shape. Moisture can be found in the cell walls and in their cavities, filling the microcapillary system. The moisture that is present in the spaces between cells and in their cavities is called free intercellular, and moisture in the cell walls is called bound intracellular.

Content in wood bound moisture limited. The state when the cell walls are characterized by maximum humidity when in contact with liquid moisture is called their saturation limit. It is generally accepted that the moisture content of the saturation limit does not depend on the rock and is on average 30%. If the wood's humidity is above 30%, then it contains free intercellular moisture. The wood of a freshly cut or growing tree has a moisture content above the saturation limit, that is, it is raw.

Depending on the purpose of wood blanks, wood is usually dried in different ways. The wood is dried to a moisture content of 6 - 8%, when the material is needed for mechanical processing and assembly of products for high-precision critical connections that affect performance (the production of skis, parquet or musical instruments).

Transport humidity is 18 - 22%. It is with this water content that lumber is suitable for transportation to long distances during the warm season. Wood dried to such a moisture content is used mainly in standard house construction, in the production of ordinary containers and when there is no need for interchangeability during assembly.

Carpentry dampness is divided into several subspecies. Molded products ( terrace board, sheathing, floorboard, casing) must have a humidity of 15 ± 2%. Wood products (windows, doors, stairs and interior elements) made from solid or laminated wood can withstand humidity fluctuations from 8 to 15%.

Furniture humidity, depending on the level of the product and the use of solid or laminated wood, is 8 ± 2%, because it is at this humidity that the wood exhibits the most optimal characteristics for processing, gluing and subsequent use. But it is usually customary to reduce the humidity to 7-10%, performing partial sterilization of the wood and taking into account the uniformity of humidity throughout the tree, maintaining the mechanical properties of the material, and the absence of surface and internal cracks.

Wood drying modes

Depending on the requirements for the quality of wood, lumber can be dried in different modes, which differ in temperature level. In the mini drying chamber for wood, during the drying process, the air temperature gradually increases in steps and decreases relative humidity agent. Drying modes are selected taking into account the thickness of the lumber, the type of wood, the final moisture content, the quality category of the wood being dried and the design of the chamber.

There are low- and high-temperature process modes. The first modes involve the use of moist air as a drying agent, the temperature of which is initial stage is less than 100 degrees. There are three categories of these modes:

• The soft mode is capable of ensuring defect-free drying of the material while maintaining the natural physical and mechanical properties of the wood, including color and strength, which is important for drying wood to the transport moisture content of export lumber.
• The normal mode guarantees defect-free drying of wood with almost complete preservation of the strength of the material with minor color changes, which is suitable for drying lumber to its final moisture content.
• The forced mode maintains strength for static bending, compression and tension, but there may be a slight decrease in splitting or spalling strength with darkening of the wood, which is intended for drying wood to operational humidity.

For low-temperature modes, a three-stage change in the parameters of the drying agent is assumed, and from each stage to the next one the transition can be made only after the material reaches a certain level of humidity, which is provided for by the mode.

High-temperature modes provide for a two-stage change in the parameters of the drying agent, and you can move from the first stage to the second after the wood reaches a transitional moisture content of 20%. The high temperature regime is determined depending on the thickness and type of lumber. High-temperature conditions can be used to dry wood, which is not used for production. load-bearing elements buildings and structures in which wood darkening and strength reduction are allowed.

Drying chamber concept

Chamber drying is the main method of drying wood. Drying chambers are required for drying softwood and hardwood to different quality categories. One of the most popular and economical methods of artificial dehydration of lumber is drying, when bound and free moisture is removed from the tree by applying heat to the wet wood with hot air and carrying away the evaporated excess moisture humidified and partially cooled air.

Drying chamber is completely ready installation, which is equipped with all the equipment necessary for drying wood. According to their design, wood drying chambers are divided into prefabricated metal ones and those made of building materials. The latter are constructed directly in workshops or as separate buildings from materials that are widely used in industry. The camera can be made entirely from monolithic reinforced concrete. Its walls can be made of solid red brick, and the ceiling can be made of monolithic reinforced concrete.

If several dryers are used, they are often combined into a single block, constructing common corridor control, where the heating distribution and system are located automatic control all cameras. Depending on the volume of wood loaded into the chamber, there may be horizontal or vertical transverse air circulation.

Loading of lumber into the chamber can be carried out in the following ways: on trolleys in the form of stacks along a rail track, like packages with a forklift. Heat transfer to wood can be carried out: by air, combustion products or superheated steam; radiant heat that comes from special emitters; a solid body, if you organize contact with a heated surface; current that passes through wet wood; high frequency electromagnetic field, which penetrates wet wood.

Equipment for a wood drying chamber is divided into basic and additional. The main ones include the fan system, heating system, supply and exhaust ventilation and humidification, additional components include an insulated door and psychrometric unit, stacking trolleys, and a fan drive electric motor.

The process of controlling wood drying in a chamber can be automated. Automation is capable of maintaining the humidity and temperature of the environment in the dryer at a given level. The temperature is regulated by supplying coolant to the heaters or by switching on and off electric heater, and humidity - through the use of supply and exhaust ventilation and a humidification system.

The wood drying control system may provide for remote control of humidity and temperature in the chamber. When drying lumber in a drying chamber, it becomes necessary to control the moisture content of the wood, for which a remote moisture meter is used, which allows you to check the moisture content of the wood at several points without entering the chamber. In the absence of external sources of heat supply, autonomous heating modules can be used for the dryer and gas, coal, wood waste, electricity and diesel fuel.

Types of drying chambers

In real life, it is common to use the following types of drying chambers. The necessary energy in convective drying chambers is transported into the material using the air cycle, and heat transfer to the wood occurs through convection. There are two types of convection chambers - tunnel and chamber.

Tunnel convection dryers are deep chambers where stacks of stacks are pushed from the wet end to the drier end. These chambers must be filled at one end and emptied at the other. Pushing the stacks (the process of filling the chambers and emptying them) is done one stack at a time with an interval of 4 - 12 hours. These chambers are designed for large sawmills and allow exclusively transport drying of wood.

Chamber convection drying chambers are shorter than tunnel and vacuum drying chambers for wood; during operation, the same parameters are maintained throughout the chamber. When the blowing depth is more than 2 meters, the technique of reversing the direction of ventilation is used to equalize the drying conditions for the wood. The emptying and filling of the chamber occurs on one side if it has one door. Other loading systems are also known that are similar to the procedure for loading tunnel chambers. Any lumber can be dried to any final moisture content, which is why 90% of wood in Europe and Russia is dried in chamber dryers.

The condensation drying chamber differs from the previous ones in that the humidity that arises in the air condenses on special coolers and water comes out of the drying process. Coefficient useful action This process is large, but the cycle is long, because the devices do not operate at high temperatures, and the total heat losses are also significant. The condensation chamber is primarily suitable for drying small volumes of wood, or for drying dense wood species - oak, beech or ash. Big advantage The advantage of such chambers is that a boiler room is not needed, the price of a drying chamber for wood and the cost of drying are lower.

Drying kilns are also classified according to the method of circulation and the nature of the drying agent used, the type of enclosure and the principle of operation. Drying chambers periodic action are characterized by the fact that they can be fully loaded for simultaneous drying of all material, and the wood drying mode changes over time, in this moment remaining the same for the entire camera.

According to the method of circulation, there are chambers with incentive and natural circulation. Dryers with natural circulation are outdated, low-performance, the drying mode in them is almost uncontrollable, and the uniformity of wood drying is unsatisfactory. For modern construction such devices are not recommended, and existing ones must be modernized. Based on the nature of the drying agent, the chambers are divided into gas, air and high-temperature chambers that operate in a superheated steam environment.

Wood drying procedure

Before drying according to the selected mode, the wood is heated with steam, which is supplied through humidifying pipes, with fans running, heating devices turned on and closed. exhaust ducts. First you need to calculate the drying chamber for wood. The temperature of the agent at the beginning of heating the wood should be 5 degrees higher than the first stage of the regime, but not more than 100 degrees Celsius. The level of saturation of the environment should be 0.98 - 1 for material with an initial humidity of more than 25%, and 0.9 - 0.92 for wood with a humidity of less than 25%.

The duration of the initial heating depends on the type of wood and for coniferous species (pine, spruce, fir and cedar) is 1 - 1.5 hours for each centimeter of thickness. The duration of heating of soft deciduous trees (aspen, birch, linden, poplar and alder) increases by 25%, and for hard deciduous species (maple, oak, ash, hornbeam, beech) - by 50% compared to the duration of heating of coniferous species.

After preheating, it is customary to bring the parameters of the drying agent to the first stage of the mode. Then you can begin drying the lumber, subject to the established regime. Humidity and temperature are regulated by valves on the steam lines and gates of the sugar-exhaust channels.

During the operation of an infrared drying chamber for wood, residual stresses arise in the wood, which can be eliminated by intermediate and final moisture-heat treatment in an environment of increased temperature and humidity. It is customary to subject lumber to processing, which is dried to operational humidity and subject to machining further.

Intermediate moisture-heat treatment is carried out during the transition from the second stage to the third or from the first to the second at high temperature conditions. Subjected to moisture and heat treatment conifers from 60 millimeters thick and deciduous from 30 millimeters thick. The temperature of the environment during the heat and moisture treatment process should be 8 degrees higher than the temperature of the second stage, but not higher than 100 degrees, with a saturation level of 0.95 - 0.97.

When the wood reaches its final average moisture content, final moisture-heat treatment can be carried out. In this process, the temperature of the medium is maintained 8 degrees above the last stage, but not higher than 100 degrees. At the end of the final moisture-heat treatment, the wood that has undergone drying must be kept in the chambers for 2 - 3 hours at the parameters provided for by the last stage of the regime. Then the drying chamber is stopped.

Making a drying chamber

If you decide to make wood products yourself, then you simply need a wood drying chamber. However, when constructing a dryer, comply with all required standards. You will need a chamber, a fan, insulation and a heating device.

Line up the dryer or highlight separate room, one wall and ceiling of which will be made of concrete, and the other walls will be made of wood that need to be insulated. To do this, it is customary to create several layers: the first of them is polystyrene foam, the second is wooden boards, which are usually wrapped in foil in advance.

After this, you should install a heating element, which can be made in the form of batteries. Water must be supplied to the batteries from the stove, in which it will be heated to 60-95 degrees Celsius. It is advisable to continuously circulate water using water pumps in the heating element. Also, a fan should be placed in a homemade wood drying chamber, which helps distribute warm air throughout the room.

Consider how the wood will be loaded into the drying chamber. One loading option could be a rail cart. To regulate the humidity and temperature in the drying chamber, you need to use work area corresponding thermometers - wet and dry. Provide shelves inside the dryer to increase work space.

During the drying process of lumber, sudden changes in temperature in the working room are not allowed, otherwise this will cause the wood to warp or cracks to appear in it. When constructing a drying chamber, it is extremely important to observe fire safety requirements. Therefore, be sure to install fire extinguishers in the immediate vicinity of the dryer.

And finally, remember that instead of heating element At home, you can use a two-burner electric stove. You can insulate the walls of the drying chamber yourself using wood shavings. Instead of foil in the chamber, you can use penofol, which can provide good reflection of heat from the surface. In such a dryer, the wood is pre-dried 1-2 weeks in advance.

Since ancient times, dry wood has been used to make wood products. Products made from a damp wood base quickly became unusable, so specially for obtaining high quality material the tree was kept for several years, trying to dry it.

When wood dries, it shrinks, compacts and curls, so before making log houses or lumber, it is necessary to dry the wood thoroughly. You also need to dry the wood correctly, you need to achieve a certain percentage humidity, you should not overdry the materials, since dried wood will strongly absorb moisture, swell and crack.

Cut trees are dried, as a rule, in special drying chambers that resemble an oven. Next, we will discuss what drying devices exist, how to use them, and whether it is possible to make a dryer with your own hands.

Types of devices for drying wood

In large industrial production, cut trees are dried in specialized drying buildings that look like huge ovens. The moisture content in wood is reduced by treating the source material with heated air. This design ensures the technological process of drying the wood for further processing. Such devices are made in several versions; it is possible to manufacture the dryer body from:

• Metal, in one-piece version;
• A variety of building materials as a prefabricated structure.

Prefabricated structures are installed directly on site, in the form of structures and free-standing buildings. The walls are welded from the frame and sheathed metal sheet, you can fill the walls with concrete mortar or use brick. Large timber processing plants create a whole system of drying rooms, combining several modules with a single central control and control over the technological process. Prefabricated structures in the form of free-standing buildings are welded from a frame and covered with a metal sheet; they can be filled with concrete mortar or bricks can be used.

The basic principle is heating the wood with warm air. Due to its circulation inside the drying chamber, the lumber is actively heated and dried. There can be several heat sources:

• hot steam;
• smoke from burning wood;
• just heated air;
• electric heating elements;
• infrared energy;
• electromagnetic fields in the high frequency range.

In addition, drying devices are equipped additional systems, which help to carry out the technological process of wood drying more efficiently. This:

• supply and exhaust air injection and removal systems;
• additional heat sources;
• moisturizing systems.

Drying rooms differ in their operating principle; they can function:

• on convection equipment;
• on condensing boilers;
• on wood;
• as aerodynamic dryers;
• on solar infrared batteries;
• like vacuum ones.

Operating principle of convection dryers

Convection drying devices built on the principle of circulating warm air between the original lumber. In one cycle, which lasts from 5 to 14 hours, the wood is dried to the desired percentage of humidity. In addition, the fundamental difference between convection dryers is that the wood is heated by a gaseous coolant. It could be:

• heated air-gas mixture;
• gases products of combustion.

When wood material is heated, moisture is released, which is thrown out with the coolant.

Drying chambers closed type in the form of a separate box, they are more compact and differ in that a constant set temperature and humidity are maintained throughout the entire volume of the chamber. This design of the ovens allows drying the original wood material any variety, to the required humidity.

Building a drying chamber, step-by-step instructions

To make a drying chamber with your own hands, there is no need to prepare complex technical drawings. You just need to provide the following:

• Place for installing a drying chamber.
• Insulation (thermal insulation) of the entire structure.
• Heating sources.
• Ventilation or air circulation system.

The area of ​​drying chambers built by yourself is usually small, usually up to 10 square meters. meters. These are square rooms suitable for the circulation of warm air flows. It is recommended to build at least one wall of concrete, the rest can be made of wood. The inside of the chamber must be lined with a heat insulator; a good material should be selected to retain heat inside.

For example, excellent and at the same time inexpensive insulation material- wood shavings. It is also necessary to lay a layer of foil, which will retain heat.

You can make a dryer for lumber from an aluminum sheet by constructing a frame from wood or a profile, and covering it with metal sheet aluminum, you can get a structure that will last for a long time. It is important to take care of a good thick layer thermal insulation material, thickness not less than 150 mm. Otherwise, you may encounter large heat losses, i.e. the street will be heated. The floor must be covered with roofing felt or similar rolled material; a layer of wood shavings is poured over the top, which will serve as an additional heat insulator.

Theoretically, after harvesting and sawing wood raw materials, you don’t have to dry the wood. There is also a demand for raw goods, but dried material is almost twice as expensive. And the deeper the processing of lumber, the higher the selling price and, accordingly, the economic efficiency of the company.

Their main disadvantages of convection drying systems include:

• Increased electricity consumption in air dryers;
• The high price of condensation drying devices, and the duration of the drying cycle is increased by 1.5-2 times;
• increased price vacuum devices, as well as problems in their maintenance and operation.

The convective drying method is the most advantageous for industrial volumes of wood of various species. Such devices are much cheaper, easier to operate and maintain, and therefore more reliable. To increase efficiency, convection dryers will remain the best option.

Complete set of drying chambers

Let's say a few words about the configuration of lumber dryers in various designs. Is there a minimum required set of equipment that makes up the “basic” package?

Experts say that standard solutions, as a rule, do not exist. Most manufacturers of drying devices for lumber have an individual approach to the requirements and conditions of each specific technology. The complete set of drying structures can be almost anything - from the minimum required to fully equipped complexes of drying ovens with boilers operating on forest waste. Experience shows that the most common configuration options are the following:

• supply of devices and instruments to complete an existing or newly constructed drying building;
• complete delivery together with the design of the prefabricated structure with equipment and controls.

Another characteristic feature of the operation of convection drying devices for lumber is humidity control systems. Humidity content of air inside the chamber – important parameter, influencing the technology of sawlog drying. The higher the temperature of the coolant in the chamber, the faster the lumber dries, but at high temperatures the humidity is several times higher than the moisture content environment. And in convection dryers, air exchange volumes exceed 2% of the total circulating air per hour.

Dryer body

The body of the kiln for drying lumber is a metal structure built on a foundation. The frame and walls are usually made of aluminum or carbon steel sheets with anti-corrosion coating. Internal structural elements: deflectors, dropped ceilings and control system units, as well as auxiliary structures are made of aluminum, and mineral wool is used as insulation.

Particular attention should be paid to mineral wool, since the use of low-quality products can give a negative result. Therefore, you should use only well-known mineral wool from trusted companies, which will prevent the heat insulator from settling, and the gaps will allow the insulation to dry even if moisture gets in.

Conclusion

The main thing to remember is that it is impossible to allow sudden changes in temperature limits indoors while drying lumber, otherwise this will lead to damage to the material, warping of the wood and the occurrence of cracks. When constructing a drying structure, it is necessary to comply with fire safety standards. Fire extinguishers must be installed near the stove.

You can insulate the walls of a drying oven yourself using wood shavings. As an option, use penofol instead of foil in the chamber, which can create a good reflection of heat from the surface. IN similar design The wood is dried for 1-2 weeks.

Any lumber is obtained by longitudinal sawing of a log. The result is bars, slats, and boards of various thicknesses necessary for construction and repair. Only dry lumber is used in construction. They have higher quality indicators. To dry wood at home, you can equip a special do-it-yourself lumber dryer. The construction process of this structure will take a lot of time. But as a result, the home master will always be provided with quality material to perform various jobs.

The quality of the timber depends on how dry the wood is. The moisture content of the timber should be 12%.

Construction of a dryer

Construction of a simple dryer for drying small volumes of wood with your own hands under natural conditions consists of several stages:

1. It is necessary to select and prepare an area to place the building. You can build a dryer on the adjacent building plot of land. For the construction of a dryer small size will do flat roof. The floor can be made from several layers of roofing felt, sprinkled with sawdust.
2. Wood to be dried is placed in a stack no more than 120 cm wide. Optimal size its width is 80 cm. The stacking height is 50-70 cm. Separate layers of boards or beams are laid with slats at least 2 cm thick. It is recommended to lay the stack across the air flow in this area.
3. Provides protection from rain and snow. Dry ones are placed on the top row of the stack. wooden beams cross section approximately 50x50 mm. Iron is placed on them, which is pressed against the same beams.

In such a dryer, the material is blown with air, the moisture gradually evaporates, and the humidity level decreases.

Drying chamber

The most efficient way to dry wood is in a special drying chamber. It can be installed automatic systems, which control the entire drying process of wood of specific species. At the output, the lumber will have a predetermined moisture level. You can also build such a camera yourself. But this building will cost a lot of money. For construction you will need:

• aluminum profile;
• sheet metal;
• thermal insulation material;
• waterproofing film;
• sawdust;
• heat construction gun.

Construction is carried out in the following order:

1. You should start with the construction of a foundation of any type. It can be piled or strip. For its construction you can use brick, concrete, metal pipes and other materials. It all depends on the size of the camera.
2. A frame is built on the foundation. The best way to do this is to use aluminum profile. It is assembled using bolts and nuts. Other methods of connecting frame elements are possible.
3. The finished frame is sheathed with aluminum or steel sheets. They are fastened using self-tapping screws, bolts, and welding. The walls can be made of brick, concrete, or other materials.
4. Thermal insulation is installed from mineral wool 10-15 cm thick.
5. The floor is covered waterproofing film and sawdust.
6. To lay stacks of lumber, supports are prepared from bars in the form of a kind of well. This is done in order to raise the bottom row of the stack above the floor level.
7. Lumber prepared for drying is stacked through wooden spacers. Air should flow freely between the rows of boards. The height of the stack is limited only by the height of the ceiling.
8. For forced circulation fan heaters or other heating devices are installed to provide heated air. The air flow should be directed across the location of the boards in the stack. This promotes a more efficient drying process.

Dryer inside the house

A small number of boards can be dried inside the house or cottage. The dryer is arranged like this:

1. You need to choose a room that has a fireplace or stove. Can be used electric fireplaces and ovens.
2. The room is separated from the rest of the house by partitions. Tightly closing doors are installed. A window may be needed for ventilation. All cracks must be sealed, since extraneous air flows and drafts negatively affect the quality of the dried material. It is also recommended to insulate the walls. On top of the insulation, they can be lined with brick, which well maintains heat from the stove and from electric heating devices. Fans are installed to force the circulation of warm air.
3. Raw lumber is stacked on specially made durable metal shelves.

Before drying, you need to check the moisture level of the material. This is done using a moisture meter. High humidity causes early wear and tear of buildings, the appearance of mold and mildew. Overdried wood becomes deformed due to moisture absorption and swelling. Wood is usually dried to a moisture level of about 8-12%. To prevent it from cracking, experts recommend treating the ends of the boards with a mixture of drying oil and sifted chalk. The consistency of the mixture resembles thick sour cream.

Lumber can be dried either with or without bark. You just need to remember that birch, aspen, poplar and beech in the bark can be affected by rot. In general, the drying process can last up to 2 weeks. During this time, temperature changes in the dryer should not be allowed. There should be a fire extinguisher in the dryer room. This is required by safety regulations.

Operating modes of the drying chamber

The camera should not be immediately heated to high temperature. In normal mode it works like this:

1. Within 15-20 hours, the air in the chamber is heated to approximately 45°C. The ventilation system is not working yet. Moisture should appear on the walls of the chamber.
2. When the temperature reaches 45°C, the supply air should be opened by a third and exhaust system ventilation. In about 2 days the temperature rises to 50°C.
3. The dampers must be fully opened and the temperature must be brought to 55°C. This is usually sufficient for normal process drying As soon as the humidity reaches approximately 8%, all dampers must be completely closed and the heat supply must be turned off. The fans continue to run for another day. Once the temperature drops to 40°C, dry lumber should be ready for use.

Optional equipment

As additional equipment You can install automatic equipment in the drying chamber. Its properties:

• the system is capable of working with cameras different sizes and with different heat sources;
• is relatively cheap;
• does not require special knowledge to maintain it;
• is easy to install;
• measures temperature and humidity in the chamber;
• provides fully automatic or semi-automatic operation of the drying chamber;
• automatically controls the operation of valves, dampers and fans.

To operate the system, it is enough to set the thickness and type of lumber and the desired final moisture content. The system helps dry various breeds wood: pine, spruce, oak, birch, beech, linden, ash, maple, alder, hornbeam, poplar, aspen, sycamore. Every 2 hours, the automation takes readings of humidity and temperature and makes the necessary adjustments to the operation of all air heating and ventilation systems. approximate cost Such a system ranges from $400-450.

Building a dryer with your own hands is quite troublesome and expensive.

But the result covers all costs. This is especially important for those who manufacture wooden products like furniture and wood carvings. Dry wood costs several times more than raw wood. In addition, in your own dryer you can achieve a certain moisture content of the workpieces. Everything can be done independently if you have a strong desire and the availability of a suitable place.