Wood drying equipment. Arrangement and construction of a drying chamber for lumber. Technical characteristics of drying chambers

One of the mandatory stages in the production of wood materials is harvested timber, produced outdoors and in special chambers, which protects the timber from fungus, prevents deformation and changes in parameters.

Drying chambers for lumber operate in a certain mode, which is selected depending on the initial moisture content, wood species, board thickness, planned use, taking into account the design features of the dryer.

The installation can also dry firewood, which is used in solid fuel heating boilers, fireplaces.

Drying modes

During the drying process, the oven can operate in low temperature, normal or high temperature mode.

Low temperature and normal mode

Low-temperature wood processing is carried out at 45 °. This is the mildest method, it retains all the original properties of the wood to the smallest nuances and is considered a high quality technology. At the end of the process, the moisture content of the wood is about 20%, that is, such drying can be considered preliminary.

As for the normal mode, it takes place at temperatures up to 90 °. After drying, the material does not change shape and size, the color brightness and strength are slightly reduced. This is the most common technology used for various types of wood.

High temperature mode

In this mode, drying takes place due to the action of superheated steam (temperature over 100 °) or hot air. The high-temperature drying process reduces the strength of the wood, imparts a darker shade, so the material is used to create minor building and furniture units. In this case, drying with superheated steam will be more gentle than using air.

Types of drying chambers

Dryer for boards can be with natural or forced air exchange. Moreover, the first option is ineffective and unpredictable. Therefore, in order to avoid unnecessary risks, chambers with natural drying are almost not used at present.

By the principle of operation, the following types of dryers can be distinguished:

convective;
condensing;
vacuum;
aerodynamic;
Microwave cameras.

The difference between chambers in dryers for wood is what equipment is used to heat the air, circulate it and lower the pressure.

Convective

The drying chamber of the convection (convection) type is a rectangular insulated container with powerful ventilation in the ceiling edge, due to which air is distributed through the heaters and wood. As a result of heating, the moisture of the lumber turns into steam, then it leaves the chamber through special valves. This process of exchange of thermal energy is called convection.

Convective dryers are produced in two types: tunnel and chamber. In the first design, the boards enter the chamber from one side and are unloaded from the opposite side. These models are mobile and designed for use in large sawmills.

Chamber drying plants provide for the launch and unloading of sawn timber through one door.

Convection chambers have the following features:

in one cycle, you can process 20 cubic meters of wood, provided that the volume is completely filled;
it is possible to dry all types of sawn timber by stacking with gaps;
after drying, it is possible to perform steaming, impregnation of products;
when connecting a solid fuel boiler for heating, the process will be more economical;
the design is large, therefore it is intended for stationary work (without leaving).

The advantages include a high quality of drying, but if the chamber is not filled to 100%, then there will be a high probability of obtaining poorly dried wood (with overheating or high humidity) due to the uneven passage of hot air flows through the products. A possible disadvantage is high power consumption.

Condensing

Condensing drying chambers are similar in design to convection chambers, but differ in the principle of operation. Wet steam generated during wood drying turns into water (condenses), which is collected in special containers. This technology is achieved due to the tightness of the drying chamber. Reserves of the obtained water are used for space heating.

Despite the efficiency of condensing units, the drying process takes a long time (about 2-3 weeks), while in convective units it takes from 1 to 2 weeks. Also, the disadvantage is the high cost of the unit.

Vacuum

The dryer works on the principle of vacuum removal of excess moisture, the drying process consists of three stages: heating (preparatory), drying (with humidification), and cooling. Over the full drying period, about 250 identical cycles are performed. The presence of a vacuum softens the effects of high temperatures and prevents the wood from cracking.

The differences in the vacuum drying chamber are:

fast drying of wood;
energy savings as a result of the temperature rise of the functional heating plates inserted between the lumber.

Vacuum chambers are expensive to purchase and maintain, so drying pine or spruce in them is unprofitable.

Aerodynamic

The installation is a metal box with high-quality thermal insulation. The moisture formed as a result of drying drains into a special collector. The heated air circulates in a closed space using a special aerodynamic propeller, which gives its energy to the drying process.

The chamber must be fully loaded with lumber, only then the quality of the work will not suffer. Maintenance of an aerodynamic wood dryer does not require specific knowledge, the installation is fully automated.

The disadvantages are the relatively long drying process (about 20 days), high energy consumption, lack of temperature control.

Microwave cameras

Microwave drying technology has been developed relatively recently. The installation is a closed metal container with a door in the end wall and operates on the principle of a microwave oven. Microwave radiation heats up the wood, from which water molecules are squeezed out under pressure.

The camera is convenient in that it can be positioned anywhere in the room. Due to the powerful effect of electromagnetic waves, wood drying takes no more than 6 days.

The advantage of the microwave installation is also in the high quality of drying when the mode is correctly selected.

The dryer is expensive due to the high consumption of electricity and the need to change the main spare part - the magnetron (a device for emitting electromagnetic waves) from time to time.

DIY making

Drying wood privately requires a special chamber that you can make yourself. If you have to build a wood dryer with your own hands, then on a plot of land you need to allocate an area of about 10 m 2 for installation. You will need concrete for the foundation, material and insulation for the walls, foam, ventilation system, boiler and auxiliary equipment.

Construction stages

The construction of a mini-dryer consists of successive stages:

preparation of the foundation for the installation;
walling;
thermal insulation;
roof and door installation;
installation of radiators and fans on the ceiling;
installation of the boiler in compliance with safety precautions, piping.

Such work will be justified with the regular use of the finished object. The drying chamber will need to be fully loaded and strictly adhere to the drying technology.

Foundation construction

The site is marked taking into account the length of the lumber and the total width of the stacked stacks plus a loading allowance of about 30 cm.

After marking the site, it must be concreted in such a way that the floor level of the chamber is about 10 cm higher than the ground level. The concrete site is made with bumpers protruding half a meter. To prevent water from accumulating in the drying chamber, the foundation must be made with a slight slope. It is also necessary to provide for the filling of the rails for the delivery of the trolley with the products.

Walling

Bricks, sandwich panels, railway containers can be used as materials. The most common material is wood. Three walls are made of it, and the fourth is desirable to be made of concrete.

The height of the wood drying chamber is made up of the height of the stacks, a loading allowance of 30 cm and the height of the fans and radiators. When building a small chamber, the height is calculated taking into account the filling of the entire volume.

The heating of the installation requires a source of thermal energy, therefore, when installing the walls, it is required to build an extension for the boiler and its auxiliary equipment.

Insulation and installation of the roof

Dry shavings or sawdust, which are applied to the walls in the form of a mixture with cement and an antiseptic, can serve as an effective and economical heat-insulating material. To preserve heat, the floor is covered with shavings.

The roof of a homemade room is mounted with a slope so that the snow does not linger on it. Then the doors are installed by hanging on an I-beam or swing doors.

Equipment installation

Align the fans vertically across the width of the ceiling to ensure uniform heat delivery. The next row will consist of radiators. To keep the heat in the drying chamber, you first need to seal the cracks with polyurethane foam.

The heat is supplied to the radiators from the boiler, which can run on electricity, liquid or solid fuel. Usually, a wood-burning boiler is chosen for heating the drying chamber. Pipes are brought to the boiler, then an anti-explosion valve is installed, which regulates the operation of the equipment.

Obligatory and correct drying in a home-made or purchased drying chamber is a reliable guarantee of the quality of lumber.

The lumber dryer is an industrial equipment used to dry raw timber for further processing. Today, wood drying in drying chambers is carried out by several types of such devices, each of which has its own specific functional features. However, in fact they are all universal. They can be used to dry any type of timber. With the help of the latest drying chambers, high-quality drying of wood of even the most exotic and expensive varieties, for example, rosewood, beech, wenge or teak, is carried out. At the same time, there is no cracking and other flaws.

Types of drying chambers

A large number of woodworking industries process almost 10,000 m³ of sawn timber every year. The wood drying kiln in the process chain is a critical link in quality assurance. The volume of one-time loading of timber into the drying chamber is very different. Sometimes you need to dry 6 m³, but sometimes you need to dry up to 100 m³. The main factor when choosing the size of the drying chamber can be called the production capacity.

Drying methods are classified according to the characteristics of heat transfer to the dried raw material, therefore, the following types of chambers are distinguished:

dielectric - require high energy costs
convector
vacuum. Such devices are distinguished by their high price and expensive maintenance.
aerodynamic. These devices require a lot of power.

Chamber drying of wood using various methods was invented in the 60s of the last century, however, due to high energy costs and the complexity of the design, drying has become popular only in the last decade. The most popular all over the world are convection-type chambers.

Convection dryers

The convector-type wood drying chamber is used for various types of timber. These devices are simple in design, low maintenance and reliable. That is why they are most popular in production.

Work is carried out by heating from a gaseous carrier (drying agent). When heated, the raw material dries out. The drying agent can be steam, flue gas or air. Moisture, which is released from timber, serves for additional moistening of the agent, and the excess is sucked out with the help of ventilation.

The air exchange rate in the convection dryer does not exceed 2% of the total amount, therefore, energy savings are felt.

The camera body is made of metal and is placed on a monolithic-columnar foundation. The metal used for the enclosure is carbon steel or aluminum with an anti-corrosion coating. The body is sheathed with aluminum sheets on both sides. The chamber is insulated with mineral wool in the form of slabs. The convection chamber can be purchased from both domestic and foreign production.

Vacuum drying

The vacuum drying chamber for wood is designed for valuable types of timber such as teak, wenge, rosewood and others. Such a unit functions from convector heating of wood and vacuum removal of excess moisture. The process takes place at a maximum temperature of +65. However, due to a vacuum pressure of 0.09 MPa, boiling occurs at 45.5. Such conditions make it possible to dry the wood without the aggressive effects of high temperatures. Thus, there is no high internal stress, and the wood is not subject to cracking.

During drying, when the temperature rises to 65 degrees, the automatics are turned on and the electric boiler is turned off. The upper layers of timber cool slowly, and moisture from the inside flows to drier areas. During the period of one drying, there are about 250 such cycles. In such conditions, moisture is evenly drawn out along the length and depth of the material. After drying, the material is characterized by a moisture level in the range of 4-6%.

Aerodynamic drying

Chamber drying of lumber in aerodynamic conditions has become widespread due to the rather low price, uncomplicated design. In addition, the specific knowledge of the operating personnel is not required to operate such a device. Profitability is achieved by drying up to 2000m³ of coniferous timber per year.

Among the disadvantages are:

high level of energy consumption of the drying process. In order to dry freshly sawn wood for evaporation of 1 liter of moisture, 1.15-1.3 kWh is needed. Electricity, approximately 240-290 kWh / m³
there is no way to regulate the temperature. There is only an opportunity to slow down the speed of its increase by changing the flow area of the centrifugal fan
there is no possibility to organize technological drying according to the schedule of the "Guiding technical materials on the technology of chamber drying of wood".

Such a chamber is a rectangular box. It is convenient to load wood into it by car or by rail. Drying takes place under the influence of aerodynamic energy. Warm air moves in the chamber under the action of a special aerodynamic fan. Due to the compression of air in the chamber, the temperature increases on the centrifugal fan, namely on its blades. Consequently, aerodynamic losses become thermal energy. Heat can be driven into the chamber in reverse or dead-end, it all depends on the design features. The chamber is opened exclusively at the end of the drying cycle.

Microwave drying

Such devices have been invented quite recently. They look like a closed metal container. The work is carried out under the influence of the reflective surface of the microwave waves. The principle of operation is similar to that of a conventional microwave. With the help of a microwave chamber, raw materials of any section and dimensions are dried. Microwave cameras are distinguished by a simple design, the settings are allowed to choose any wavelength.
Therefore, a wide variety of timber can be dried. The microwave attenuation mode guarantees the regulation of the temperature inside the chamber. Reversible fans remove excess moisture from the system. They compare microwave drying with dielectric, which is considered the most efficient, but due to the high costs of electricity in Russia it is not used.

In this article:

Wood is a hygroscopic material that contains moisture from nature and has the ability to absorb it from the atmosphere. Lumber is sold in two types: natural moisture and dried. Of course, the latter are more expensive, so many entrepreneurs, equipping a sawmill, think about ways to dehydrate wood.

Moisture indicators

According to the degree of humidity, the following states of the tree are distinguished:

wet(100% humidity) - logs that have been in water for a long time (for example, transported by rafting);
freshly cut- humidity depends on the natural conditions of plant growth, and ranges from 50-100%;
air dry- material stored in the air (under a canopy) reaches parameters of 12-20%;
room-dry(8-12%) - drying in a closed, heated and well-ventilated room;
dry(humidity less than 8%) - prepared by forced release of moisture.

Why is proper drying so important?

Boards of natural moisture are larger than dried ones in size, and are cheaper. This is because lumber manufacturers set a tolerance for future shrinkage and trimming.

Humidity standards:

for building and joinery materials - 10-18%. In the manufacture of building materials, the industrial moisture content of wood should be equal to or be 1.25-3.5% lower than the operational moisture in order to avoid natural shrinkage.
for furniture production - 8-10%.

The use of lumber of natural moisture is a gross violation of the technological process... When the wood dries naturally, it will change the dimensions of the width, thickness and, accordingly, the geometry of the entire product.

For example, a 50 * 150mm edged pine board with a natural moisture content of more than 50% after a couple of months will have parameters 48 * 138 mm (with tangential sawing) and 46 * 144 (with radial sawing). Even if we take into account that the length of the product will remain the same (on average, the deviation does not exceed 0.1%), the total difference is catastrophic!

Professional wood drying methods

1. Convective (chamber) drying

The most popular type of drying equipment is convection chambers... About 80% of manufacturers use just such dryers.

Advantages: ease of use, high rate of moisture evaporation, low voltage in the final product, high loading volume (up to 1000 m 3).

Supply and exhaust ventilation and heating systems are installed in the room (usually, heaters). Moisture parameters are measured psychrometer and are automatically adjusted. As a fuel for obtaining hot water or steam in small production, wood production wastes are used: wood chips, slabs, sawdust. It is profitable to use electricity and gas only with large production volumes, otherwise the high consumption and cost of resources will significantly reduce the cost of sawn timber.

Centrifugal or axial (depending on the configuration) fans provide an even distribution of warm air and timely removal of excess moisture to avoid warping, cracking and obtain the highest quality wood in the shortest possible time.

Price - from 160,000 rubles(depending on configuration and cargo capacity).

2. Atmospheric drying

The natural process of evaporation of moisture from wood, which requires a minimum investment, but a maximum of time. However, wood dewatered by air drying is considered the most resistant to deformation. Most often it happens like this: a tree cut down at the beginning of winter is dismissed into planks and aged under a canopy until the beginning of the construction season. In 4-6 months, the lumber manages to dry up to 15-20% moisture.

In order to avoid deformation of the boards during the drying process, the following conditions are necessary:

stacking on a horizontal flat surface;
to protect from excess moisture between the rows of stacks and in the area where drying is supposed, waterproofing is laid;
so that the boards are well ventilated, the stack is placed on concrete blocks and laid with a bar or unedged boards of the same thickness (see the figure below);
stacks are stacked at equal intervals and parallelism;
a prerequisite for preventing deformation is a uniform load, which is carried out using wedges or clamping straps (see figure below);
The finished stack is protected from the weather, covered with a profile or slate. With this arrangement of the dryer, the edged board will reach 12-18% moisture indicators in 4-5 months. The speed and quality of dewatering depends on the climate, the amount of moisture in the atmosphere and the thickness of the board. Atmospheric drying rules are regulated by GOST 2808.1-80 for sawn softwood and GOST 7319-80 for hardwood.

Rice. Air dryer arrangement diagram

Main disadvantages: the structure takes up a lot of space, the drying process is uncontrolled, and in areas with high humidity there is a high risk of fungus damage to lumber. For such an area, it is recommended to pre-treat the boards with an antiseptic.

3. Vacuum dryer

It is used for drying large-sized wood, hardwood (for example, oak), valuable wood that is prone to cracking. The dryer is a sealed stainless steel chamber in which boards are placed between aluminum heating plates. The top of the chamber is closed with an elastic rubber cover attached to a metal frame.

Hot water is continuously circulated over the plates, which is heated by an external boiler. The vacuum inside the chamber is provided by a pump that pumps moisture out of the room.

Rice. Vacuum chamber operation diagram

A microprocessor is used to control the processes inside the chamber. For each type of wood, the operator sets his own vacuum level and the heating temperature of the plates. For example, a 32 mm thick beech board reaches 8% moisture in 29 hours, while a 25 mm thick pine board takes 17 hours. Therefore, the main advantage of vacuum drying is the speed of material processing..

Disadvantages: small capacity of chambers (up to 10 m 3), high energy consumption, high internal stress due to uneven distribution of the final moisture content over the thickness of the material. These disadvantages are eliminated in new vacuum models, where drying is carried out using hot steam.

But the price of such cameras is high: 250,000 rubles with a load volume of 1 m 3.

4. Microwave dryer

The essence of the "microwave" method: the wood is saturated with moisture, which then evaporates at the level of cellular structures. Dehydration of wood is carried out by high-frequency currents - 915-2500 MHz.

The electromagnetic field affects the stacked sawn timber in the space of the metal chamber. Heating of wood occurs at a level of 50-60 degrees, therefore it is considered close to natural conditions.

Main pros:

mobility;
compact size;
the drying speed is 30% higher than that of convection chambers, with relatively low energy costs (for drying 1m 3 of pine - 550 kW / h, oak - 2000 kW / h).

Disadvantages:

small volumes of loading (up to 4.5 m 3 for hard deciduous trees and up to 7 m 3 for conifers);
high price of magnetron generators with a sufficiently small resource of their operation (no more than 650 hours);
uneven drying;
the possibility of ignition of the material inside the chamber - the microwave method is quite new, and the drying modes have not yet been worked out.

5. Drying by condensation method

Innovative equipment that has no analogues in the domestic production of drying chambers (Nardi, Vanicek, Hildebrand-Brunner brands are represented on the market from foreign manufacturers).

Dehydration of sawn timber is carried out by a closed cycle method - without air access from the outside.

The air inside the chamber is saturated with moisture evaporated from the wood, washes the surface of the freon cooler, and its temperature drops below the dew point. The moisture condenses, and the released heat is spent on heating the drying agent.

Rice. The principle of operation of equipment with condensation drying technology

Main advantage: energy consumption is 3 times less compared to batch dryers (up to 0.5 kW / h per 1 liter of evaporated water). Such chambers are used in cases where electricity is the only available or the cheapest type of heat carrier.

Disadvantages: low productivity, the duration of the drying process is 2-3 times longer than in chamber equipment.

The choice of a method and equipment suitable for drying wood is considered individually for each business, since it depends on a number of factors:

climatic conditions of the area;
the size of the production area;
assortment of raw materials and lumber produced;
the cost of energy resources, investment opportunities of a potential consumer, etc.

The drying chamber is the most important equipment in woodworking enterprises, as it allows you to remove moisture from lumber, heat-treat wood to prevent biological destruction, impart resistance to decay, maintain mechanical strength at the lowest density, and create minimum thermal conductivity and electrical conductivity in wood.

What are drying chambers and complexes?

Drying chambers are industrial equipment used for drying various types of lumber and wood species, deciduous or coniferous, for fumigating pallets. For processing large volumes of wood, modular chambers are combined, creating large-sized drying complexes.

Types of drying chambers and drying modes

LLC "MAKIL PLUS" offers drying chambers for lumber, with boilers (heating units) burning (utilizing) wood waste, which are divided into two types, depending on the heat carrier used:

Heat carrier - water... These installations consist of a boiler and water heaters, circulation pumps, automation adapted for use in cold weather (anti-freeze system), and a water treatment system. The system copes well under the condition of water softening, and the boiler power is selected based on the volume of the drying chambers and additional consumers. Based on the above, a drying complex for drying water-type sawn timber has a high initial cost of the project, since it includes many expensive elements and requires specialized installation.
Heat carrier - air... The system includes an air heating unit with a capacity of 100 - 500 kW, a centrifugal fan and an air duct system. The initial cost of this equipment is included in the price of the camera, the customer receives a turnkey solution without additional investment. The universal air heater has a higher efficiency compared to a water boiler and is capable of delivering both a minimum and a higher temperature than a water-type wood drying chamber.

For wood processing in drying complexes, three main modes can be used: soft, medium and forced. While maintaining a mild regime with a temperature of up to 55 ° C, during the drying process, the wood retains all its properties, without changing its strength and color. When using medium (normal) mode with temperatures up to 67-70 ° C, the shade of the wood changes slightly. For high temperatures up to 85-90 ° C with forced mode, fast drying is characteristic, but with darkening of the wood.

Technologies used by the company in the manufacture of cameras

The main advantage of wood drying chambers is:

Autonomous operation of the system in the absence of heating networks
Minimum fuel costs with simultaneous waste disposal
Compactness of placement of main and auxiliary equipment
The ability to dismantle the equipment and move it to the prepared foundation
High degree of thermal insulation of the chamber as a whole, tightness and insulation of sliding gates
Rapid warming up to the required temperature
Minimum heat loss through structures
Desiccant and coolant both air and water.
Possibility of quick conversion for a coolant.
Ease of maintenance, ease of management.
The ability to dry in any mode.
Drying complexes are made of 80% of Russian materials that do not require long waiting times for replacement.
The modular design allows new drying chambers to be added without stopping existing chambers.
Thermally protected reversible axial fans with Siemens electric motors /
Drying process control system Litouch from the world leader Logika
The controller can be programmed for up to 16 phases of lumber drying, which allows you to create special climatic conditions inside the chamber for the drying process.
High maintainability during operation

These technologies not only allow drying lumber without discoloration and cracking, but also ensure trouble-free operation of the equipment.

The economic return on wood waste chambers

Economic payback is one of the benefits of MAKIL PLUS equipment. A drying complex for wood, on average, pays off within a year, since the cost of drying 1 cubic meter, including the cost of maintaining the device, is about 450 rubles. In addition, the purchase of a completely ready-to-use installation solves the problem of wood waste disposal. At the same time, mixed waste is suitable for work, even with a high percentage of moisture.

The company "MAKIL PLUS" puts on sale drying equipment with chambers with a volume of 10 to 140 m 3, which are manufactured both according to ready-made projects and to individual requirements of the customer. Drying complexes for wood "MAKIL PLUS" are already operating in every region of Russia and are becoming more and more in demand every day.

More detailed information on this equipment and its purchase can be obtained by contacting the managers of our company.

Content:

All woodworking enterprises profit from the sale of their products. And the deeper the wood processing, the more profitable the production. Before buying equipment, every entrepreneur asks questions: What kind of drying chambers for wood are, what devices are equipped, and which one to choose for their production?

If you choose the wrong equipment, the profitability, on the contrary, will fall. And the wider range of wood kilns on the market makes the selection task even more difficult.

The main types of drying chambers are:

Dielectric.
Convection
Vacuum
Aerodynamic

The method of drying wood in various ways was invented back in the 60s, but due to the high costs of electricity and the complexity of the design, technologies have only recently begun to be used. Convector dryers are most often used all over the world. Why is this happening? The rest of the designs can be used with a number of restrictions and subtleties of use. The main disadvantages of using inductive, condensing and vacuum dryers for wood:

Aerodynamic chambers require more energy consumption;
Condensing constructions are expensive, and drying in them lasts 2 times longer than in convector ones.
Vacuum dryers are expensive and expensive to maintain.
Dielectric ones require high energy costs, although they are considered among the best.

Convection dryers

Convectors are used for drying wood of various species and sizes. Due to the simplicity of the design, the convection chambers are inexpensive to maintain, which speaks of reliability. Therefore, in order to increase profitability, in 90 cases out of a hundred, they are purchased.

The principle of operation of the convection dryer

Heating comes from a gaseous carrier (drying agent). When heated, the raw material is tapped. The drying agent can be steam, flue gas, air. The moisture released from the wood serves as an additional humidification of the agent, the excess is exhausted by ventilation into the atmosphere.

Air exchange in a convection dryer is not more than 2% of the total amount, so the energy efficiency is noticeable.

Complete set and equipment of the convector dryer

There are many configurations from various manufacturers, but there are basic options:

Equipment for an already built or just under construction hangar of a drying structure.
Fully structured with hardware.

Equipment case

The body is completely made of metal, assembled on a monolithic-columnar foundation. The metal used for the manufacture is carbon steel or aluminum with a corrosion-resistant coating. Outside and inside, the hangar is sheathed with aluminum sheets. Individual elements inside the structure (deflectors, false streams, amplifiers, etc.) are also made of aluminum. The chamber is insulated with mineral wool in the form of slabs.

The construction is being assembled in compliance with GOST and SNiP. Variants requiring additions and extensions are carried out according to an additionally developed scheme. The basic assembly is designed for an average snow load.

Convection chamber models

Convection drying chambers are produced by domestic and foreign companies. The most common are Helios: ASKM-7, ASKM-10, ASKM-15, ASKM-25. They are used to dry any type of wood of drying categories I, II, III and 0. According to reviews, these models work quickly, since the mechanism uses German fans. And the installation and maintenance of the ASKM models is simple. Price from 700,000 rubles, depending on the size and capacity.

Vacuum drying chambers

The constructions are specially designed for expensive types of raw materials (teak, wenge, rosewood, oak, anger, etc.). Vacuum dryers can also be used for any softwood or hardwood.

The working principle of a vacuum dryer

The vacuum dryer operates from convector heating of wood and vacuum removal of excess moisture. Temperature range is maximum +65 0С. But because of the vacuum, 0.09 MPa boils at 45.5 ° C. This allows the drying process to be carried out without the aggressive effects of high temperatures, which does not create high internal stress, and the wood does not crack.

In the process of operation, the temperature has risen by 65 ° C, the automation is triggered and the electric boiler is turned off. The upper part of the wood begins to cool down and moisture from the inside begins to flow to the drier parts. During the entire drying process, such processes can occur up to 250 times. So the moisture is evenly drawn out along the entire length and depth of the raw material. The maximum moisture drop in different parts of the tree can be 0.5-1.5%, and fully dried has a moisture content of 4-6%.

Models of popular vacuum structures

The most common model of vacuum chambers is Helios. Drying chambers for wood Helios differ in power, load volume and other technical characteristics. More information about TX Helios in the table:

Technical parameters, Helios Vacuum (HV)	GV-4	GV-6	GV-9	GV-12	GV-16
Possible volume of loaded raw materials, no more, m 3	4	6	9	12	16
Working mechanism parameters (length, width, height), cm: DShV	430/192/192	630/192/192	650/230/230	850/230/230	1230/230/230
The maximum possible heating temperature, degrees. WITH	up to 65	up to 65	up to 65	up to 65	up to 65
Discharge kg / cm2	— 0,92	— 0,92	— 0,92	— 0,92	— 0,92
Drying time for various types and sections of wood to a moisture content of 4-5%, days:
Oak, section 5.2 cm, humidity. 50%	19 — 25	19 — 25	19 — 25	19 — 25	19 — 25
Oak, section 5.2 cm, humidity 30%	11 — 13	11 — 13	11 — 13	11 — 13	11 — 13
Oak, section 2.5 cm, humidity 50%	10-11	10-11	10-11	10-11	10-11
Oak, section 2.5 cm, humidity 30%	8-9	8-9	8-9	8-9	8-9
Conifers, section 5.5 cm, humidity 50%	7-8	7-8	7-8	7-8	7-8
Conifers, section 5.5 cm, humidity 30%	6-5	6-5	6-5	6-5	6-5
Required mains voltage, V	380	380	380	380	380
Connected power, kW	15	18	30	36	72
Average used power, kW	8	10	17	20	35
Helios drying chamber size (length, width, height), m: DShV	6,12,22,4	8,12,22,4	8,32,352,4	10,323,524,0	13,323,524,0
Weight, t	4	6,5	7,7	9,5	17,5

Aerodynamic wood drying chambers

These drying chambers resemble a metal box, finished with aluminum decking. An aerodynamic chamber of various modifications is used for drying all types of wood, with a loading of 3-25 m3. Custom-designed chambers with a loading capacity of up to 43 m3 are available on request.

The good thing about the aerodynamic chamber is that the work is fully automated and the minimum number of hands is required.

The frame of the aerodynamic chamber consists of a solid metal sewn onto the supporting frame. The camera is made in the form of a quadrangular box, into which it is convenient to load a tree by a car or by rail. paths. The entire internal structure is equipped with automatic condensate collectors.

Principle of operation

Drying is carried out under the influence of aerodynamic energy. The heated air circulates in the chamber under the influence of a specially designed aerodynamic fan. The air in the chamber, due to compression, increases the temperature on the centrifugal fan, specifically on its blades. This is how aerodynamic losses are converted into heat energy.

Heat is brought into the chamber, depending on the design, in a reverse or dead-end manner. The operation of the aerodynamic chamber is started by one "start" button and opens only after the complete completion of the cycle.

Models of aerodynamic dryers

The most common dryers of the aerodynamic type Gelos CKV-25F, SKV-50F, SKV-12TA, SKV-25TA, SKV-50TA, as well as Italian EPL 65.57.41, EPL 65.72.41, EPL 65.87.41, EPL 125.72.41, EPL 125.87.41. Developed by Helios, specially for drying coniferous material. They cost from 1,500,000 rubles.

Microwave dryers

Microwave cameras were invented quite recently. Such a dryer resembles a closed metal container. Works under the influence of a reflective surface of microwave waves. Resembles the principle of operation of a microwave oven. Using a microwave camera, you can dry material of any section and size. Microwave cameras have a simple design and you can adjust the wavelength to any length. This made it possible to dry any raw material using a microwave chamber. The microwave attenuation mode allows you to adjust the temperature inside the chamber. And reversible fans remove excess moisture from the system. They compare microwave drying with dielectric, which is considered the most efficient, but due to the high costs of electricity in Russia it is not used.

The main disadvantages of microwave chambers include wood moisture control and the high price of microwave dryers and electricity costs.

Microwave Dryer Models

In Russia, this drying technology is offered by an engineering company in Moscow "Investstroy" - "Microwave-Les". A similar installation costs from 1,300,000 rubles. You need to serve the microwave-wood once every six months, at a price of 100,000 rubles.

Only half of the future profit depends on which camera the buyer chooses. Building and insulating the box is only part of all the work. it is important that the component equipment is of high quality.

Equipment for drying chambers

Equipment for dryers can be divided into types:

Thermal system.
Exhaust hood and humidification system.
Rail structure for loading and unloading

Ventilation equipment plays the role of uniform distribution of heated air. Installing a low-quality fan causes uneven drying of raw materials. According to GOST, the movement of air inside the chamber should be optimally about 3 m / s. This can be achieved by using high quality and powerful fans. All fans have a rotary or axial connection system.

This equipment depends on the capacity and model of the drying chamber. An electric heater or a heat exchanger can serve as a heat generator. They are installed only by specialists, and are used to pump and transfer heat energy to wood. A system such as a mini-boiler house on liquid, gaseous or hard fuels can also act as a heat generator. It is convenient when the work is carried out on the waste of wood production.

The electric heater has a structure consisting of a pipe and a chrome spiral wound around it. This generator has a slight advantage: a simplified process for controlling the temperature inside the chamber.

Humidification system

To ensure a constant uniform air humidity in dryers, humidification and extraction equipment is used. Humidification is carried out at the expense of a complex system of nozzles, a pipeline, an electromagnetic valve.

Exhaust is carried out using a fan (usually rotary). The equipment operates according to the following technology: when the humidity drops, the fan automatically turns off and the hood does not function. At the same time, air humidification occurs due to the vaporization of the liquid that enters the nozzle automatically when the valve is opened.

When the humidity rises, on the contrary, the valve closes and the fan turns on.

Rail loading and unloading system

This equipment is installed during the assembly phase of the camera. The system consists of rails that are permanently mounted. On top of them are attached under-stack carts, which are needed for storing wood. Raw materials are laid on them, and placed in a chamber, after drying, the carts are rolled out onto the street and packaged.

When choosing a chamber for drying wood, it is better to use the services of professionals, but do not neglect the information of specialists on the network.