The technology of vacuum drying itself is interesting in that it makes it possible to actually reduce the drying time of lumber, while the surface of the wood does not crack, and its quality is preserved. The method of vacuum drying wood was invented and patented by Dr. Ernesto Pianozzi in 1964.
Navigation:
The vacuum press-dryer consists of a hermetically sealed steel chamber, the walls of which are mainly mounted from of stainless steel, which is completely sealed. The ceiling of the vacuum drying chamber itself is covered with an elastic rubber coating, which is framed by a steel frame. Loading of boards into the chamber occurs with the application of aluminum shadows to each row of boards. The water circulating in the heating elements is heated using a boiler, which is mounted with outside cameras. Water circulation occurs using a liquid vacuum pump located inside the chamber.
After loading the wood into the chamber, the operator who controls the chamber sets the working panel the required vacuum level, and also sets the temperature of the aluminum heating plates.
Vacuum drying of wood takes place in 3 stages:
1. Heating wood at normal atmospheric pressure;
2. Then follows the drying process with heating in a vacuum environment;
3. The last, final stage consists of conditioning and cooling.
Immediately after placing the wood in the drying chamber and placing heating plates between the boards, the process of heating the wood begins. This stage involves heating the boards without using a vacuum pump. Heating does not reach 100 degrees, and, therefore, the moisture inside the boards does not boil. This way the surface of the wood does not crack.
When the temperature level required for drying is reached, a vacuum pump is immediately activated, which pumps out the remaining air. At the same time, the surface of the wood is also not deformed, since the moisture remaining in the boards comes to the surface, thereby moistening it, which in turn allows the boards to maintain their original shape. When heated rubber cover stretched over a stack of boards in the chamber, pressing it to the floor. Thanks to this mechanical effect of the vacuum, the dryer simultaneously turns into a press, which has a pressure of 1 kg/cm2, which essentially equals 10,000 kg/m2. This pressing process makes the boards absolutely even. Further, during the drying process, under the influence of a vacuum pump and temperature, moisture evaporates from the surface of the wood, and the excess is then drawn out by the pump. When the required humidity is reached, the drying process switches to conditioning.
The conditioning process involves turning off the heating aluminum plates, while maintaining a vacuum in the chamber. Thus, the wood cools under the pressure created by the press, which allows the wood to maintain its given, even shape. After the boards have completely cooled, the drying is turned off. Buying a good, reliable vacuum dryer will not be any particular problem; the price of the chamber is calculated for each chamber individually, and depends on several factors:
Drying speed
It largely depends on the structure and thickness of the boards. The softer and thinner the wood, the faster the drying process will occur. Accordingly, the price of the chamber depends, among other things, on the configuration of the chamber, since a moisture condenser of different power is mounted on each chamber, which converts evaporating moisture into liquid and drains it outside the chamber.
Complete set of vacuum drying unit
Here it all depends on whether a vacuum lifter for the plates is installed, also depends on the additional equipment with additional aluminum plates, and also depends on whether it is possible to connect the control devices to the computer.
There is also a recently developed freeze drying technology. This technology is used, for example, for high-quality drying medicinal herbs, dehydration of vegetables, produce, fruits, meat and dairy products, chemical products, pharmaceutical intermediates, and many other materials.
Vacuum freeze drying is new method dehydration of products that have been deep frozen in a sublimating vacuum chamber, when the ice immediately turns into a vapor state and is removed from the chamber through sharpening with a condenser, bypassing the formation of liquid.
The design of such a vacuum drying for fruit usually includes the dryer itself, a steam condenser, a cooling system, and, if necessary, a programmable logic control system is installed.
The advantage of freeze-dried vacuum drying is that all products retain up to 95% of all useful substances. This method makes it possible to store processed products not only at a stable sub-zero temperature, which naturally increases the shelf life of processed products, but also in ordinary rooms with above-zero temperatures, which does not in any way affect the quality of dried products.
IN Lately Vacuum freeze drying is becoming increasingly common in the production of berries and fruits.
Vacuum freeze drying occurs in several stages:
1). At the first stage, the products are completely frozen to the state of ice, and the pressure should be below 4.58 mm Hg, at a temperature of 0 C;
2). Next stage involves the process of sublimation of ice formations. In this case, the pressure in the chamber is much lower than the pressure of ice evaporation due to the fact that a vacuum is maintained in the chamber. The product placed in the drying chamber is heated, and then the water vapor is removed outside the chamber through a condenser.
3).The secondary drying stage involves removing residual moisture from the product placed in the chamber by increasing the temperature in the sublimation vacuum chamber and simultaneously reducing the pressure in the chamber itself.
IN last years Vacuum freeze drying of products is being used more and more actively. According to some experts, over time vacuum drying products will eventually supplant current technologies for food preparation, in which coagulation of proteins contained in the product occurs, which in turn leads to inevitable loss nutrients. At the same time, vacuum drying of products preserves most of the nutrients, and also preserves taste, nutritional value, and vitamins. Products processed in this way are “raw” in terms of product freshness. Previous studies have shown that strawberries after treatment have a 100% retention rate of vitamin C, while the loss of “total oxidative capacity” was only 8%. For comparison, in strawberries that were simply cooled using the old method, after a week of storage, the loss of the above vitamin C was more than 20%, in addition, the researchers noted a significant loss of phenolic components, which is about 85%.
The following can be added to the advantages of freeze-dried products:
— Very long-term, long-term storage;
— Relatively low weight of products;
— The original shape is completely preserved.
Today, such drying is an almost ideal method of preserving food. This method allows you to store products for up to five years at different temperatures, from - 50 degrees Celsius to + 40 degrees above zero.
Let's talk a little more about vacuum drying of wood
Vacuum drying chambers can be, among other things, a cylindrical body with a diameter of 2000 mm - 2700 mm, a length of 7800 mm - 12000 mm, with a built-in working vestibule. Thermal insulation of the body is made from mineral wool 200 mm thick. The length of the stack of boards loaded into the chamber can reach a total of 10 meters. As in standard vacuum chambers, vacuum drying of wood here occurs by reducing the pressure in the chamber, and due to the constant decrease in the boiling point of moisture in the wood, the moisture contained in the boards quickly evaporates.
Today, the process of vacuum drying wood is the most in a practical way, and is gaining an increasing number of adherents of this method among producers of dried industrial wood.
Vacuum drying is a process that has long ago become an integral part of many types of production. A key industry that currently cannot exist without this process is the furniture industry.
Navigation:
Essentially this is special processing wood, which plays a significant role in the furniture industry. In order for the furniture to be of the highest quality and able to keep its shape for a long time, the wood must undergo a vacuum drying process, which will remove all unnecessary substances from the material, remove moisture and make the wood more durable and practical in terms of use.
But in fact, this is far from the only industry where vacuum drying plays such a big role. It is also worth highlighting the production of products, which also requires a similar process. In the case of other industries, vacuum drying works in a completely different way, since in other areas it is necessary to solve slightly different problems.
The structure of the process itself is quite complex, and there are a huge number of reasons for this.
The first is the need for large quantities equipment so that the vacuum drying process is of the highest quality.
The second is high level equipment performance, without which it is simply impossible to achieve high quality indicators.
And the third is the location, namely the presence of a specially designed room that will meet all the criteria for humidity and temperature, since without adhering to all these standards, the vacuum drying process will no longer be so effective.
As for the cost of carrying out such an operation, this is a somewhat two-fold question. The price of vacuum drying depends on what kind of material will be subject to such processing, what vacuum equipment will be used, the area in which this process will take place, the time it will take to carry out this operation, and so on.
All these points are more than important and in any case must be taken into account if your key task is to obtain high-quality processed material that can be actively used for further purposes.
Vacuum drying technology
We have already said earlier that vacuum drying is a very complex process that requires a lot of effort. Now we will look at the technology of vacuum drying, and we will do this using wood as an example, since it is in this industry that vacuum drying has gained the greatest popularity.
Before making furniture from wood, it must in any case go through a drying process, which is a key part of it. During vacuum drying, wood significantly loses its mass and decreases in size.
Now we will look at the main processes involved in vacuum drying:
- Removing water from wood using evaporation
- Circulation of water through wood
The circulation process occurs first, which, by the way, takes much longer than evaporation. The speed of vacuum drying of wood directly depends on how the water circulation process will occur.
But in no case should we forget that the drying process involves complete drying of the wood and in some cases the percentage of water in its composition reaches 30 percent, at which the saturation point of the fibers significantly decreases.
But this is not so scary, since in any case, in vacuum drying there is a rule that states that it is necessary to remove absolutely all water from the surface of the wood. After going through this process, the moisture located in the core of the tree will come out through circulation.
The process of removing moisture from the surface of wood also has certain nuances that should not be forgotten. The main thing is to remove absolutely all moisture that will come from the product by the process of diffusion.
But this was only a clear example of drying technology, where our main material was wood.
Now we will look at other areas in vacuum drying:
- Vacuum drying of liquid-viscous products
- Vacuum drying of milk
- Vacuum drying of cheese
- Vacuum drying of powders
- Vacuum drying of meat
This is not the entire list of areas where vacuum drying is an integral part. At the moment, such technology has already managed to clearly gain a foothold in most industries, which simply cannot function fully without this process.
So it is possible that soon the vacuum drying process will be used in all industries that are somehow related to the production of products.
Vacuum drying chambers
A vacuum drying chamber is a device without which such an operation is simply impossible. The role of vacuum chambers in this regard is as great as possible, and the level of performance of the vacuum drying chamber determines how quickly the drying process will occur, how high-quality the result of vacuum drying will be, and so on.
Concerning pricing policy for similar vacuum installations, then at the moment the situation in this regard is far from simple. Most of these installations are in a high price range, and not everyone can buy such an installation.
There are a huge number of types of drying chambers, each of which is intended for use in a specific industry. The principle of operation of each of the chambers differs in many ways, which is why it is very problematic to talk in detail about the principle of operation of the drying chamber
Now we will look at several types of drying chambers:
- Drying chamber for drying food
- Drying chamber for wood
- Vacuum drying cabinet
- Vacuum chamber for drying fruits
The operating principle of each camera is completely different, and the reason for this is various materials before exposure to a vacuum chamber. That is why, before buying such equipment, you should carefully read the operating instructions so as not to find yourself in an awkward position later.
Vacuum freeze drying
Freeze drying is a process that occurs by sublimating ice crystals from frozen products. This process immediately bypasses the liquid state of moisture, and allows you to dehydrate products as quickly as possible, and to do this with the highest quality possible.
With this principle of dehydration, it is possible to preserve all the properties of the products, which is a great advantage of this drying method. But this is not all that can be preserved during vacuum sublimation drying, since the anatomical structure, vitamin activity and even chemical composition products.
The vacuum freeze drying process consists of three main stages:
- Freezing the product, which is a key step, without which the further drying process simply does not make sense.
- Sublimation of ice, without the help of heat, since this is the only way to keep the product in its previous state
- Final drying in a special heated chamber, which gives the product a marketable appearance.
From all this, we can conclude that vacuum freeze drying is a process that is more than effective, and if there is a need for it, it can be used in almost all areas.
Vacuum drying of wood
Previously, we have already considered this type of drying as an example of the technology itself. There are a huge number of nuances in this technology that should be taken into account so as not to subsequently spoil the wood from which certain products will be made in the future.
The process of vacuum drying of such material is carried out only in an environment that will meet all standards of humidity, temperature and similar aspects that play a role in the final result.
The cost of such a process currently varies within the average price segment, depending on where exactly you will vacuum dry the wood. If this process is carried out more old technology, then it will cost quite inexpensively. If we are talking about modern drying chambers, then in this case it will be necessary to overpay in order to obtain the highest level of quality.
Drying of lumber is carried out mainly using a vacuum drying chamber. The technological operation consists of evaporating moisture as quickly as possible at the lowest possible pressure.
The drying chamber itself looks like a metal cylinder; it is made from boiler iron. The length of the device is up to 40 m, and the diametrical size is approximately 2 m. The chamber is hermetically sealed, the temperature inside it can be set in the range from 50° to 90°. Heating occurs by supplying water steam through pipes that are located evenly along interior walls cylinder.
Boards up to 25 mm thick are loaded into the device as raw materials, and heating occurs within 1 hour. If boards 50 mm thick are used, the duration of the heating stage increases to 2 hours. After this, the steam supply ends and the pumping of air from the chamber begins. Due to the fact that it is hermetically sealed, a 90% vacuum is formed. This state lasts 2 times longer than the previous stage and ranges from 2 to 4 hours. Evaporation of residual moisture occurs with a concomitant decrease in temperature. When the sensors inside the chamber show 30°, operation stops vacuum pump. Next, the iterations are repeated from heating to pumping out air; from 7 to 12 such cycles pass with breaks between them.
Total drying time pine boards 75 mm thick to a moisture content of no more than 10% is 3 days with an initial moisture content of 70% in the timber. If boards with the same humidity levels are dried, but their thickness does not exceed 25 mm, then the duration of the process is reduced to 24 hours.
Adjusting the drying mode in the above-described vacuum chamber is difficult, which makes the device applicable only to working with homogeneous raw materials.
When developing a vacuum compression chamber for drying, the latest technological solutions were used. The device combines the best features of classic cameras and useful innovations. The main distinguishing feature of such a chamber is its versatility, because it can dry boards of the most varied quality levels. Process goes faster than in a standard convection chamber. It is permissible to dry a solid round timber, while preventing the appearance of cracks both outside and inside.
Drying in a compression chamber makes it possible to change the color of the material at the request of the customer; the change can be so radical that the original rock becomes completely unrecognizable.
By drying, it is also possible to reduce the hygroscopicity of lumber, thus eliminating the lack of raw materials, which depends on fluctuations in atmospheric humidity that occur during tree growth. The compression chamber allows you to work with boards of a given nonlinear shape. The operating pressure inside the device is low, so the device does not come under the attention of the Boiler Supervision Inspectorate.
During the drying cycle, there is a permanent increase in air temperature, which causes an increase in the moisture capacity of the drying agent. The removal of moisture from the board is fully automatically regulated. The evaporation of liquid from the timber is explained by the influence of differences in humidity levels and depends on the coefficient of moisture conductivity. The moisture capacity of the drying agent increases along with its pressure: this occurs along with an increase in temperature values in order to ensure the safety of the drying process. The higher the pressure of the drying agent, the higher the boiling point of water (at a given temperature). The heat supply ends at the moment when the preset parameters are reached, including the equilibrium moisture content of the board in certain conditions(in the physical environment of hot steam under conditions high pressure). The calculation of the necessary parameters is based on the diagram of the equilibrium moisture content of wood for atmospheric pressure.
Until the heat supply was stopped, the operating principle of a vacuum convection drying chamber was no different from standard convection drying, with a few exceptions. Higher temperature values are used, which speeds up the drying process; the possibility of exchanging moisture with elements of the external environment is excluded; this is possible by increasing the moisture capacity inside the device itself. The condensing unit is automatically started. In accordance with the previously set program, it changes the temperature downwards, and a programmatic decrease in the pressure and humidity level of the drying agent also occurs. The decrease in temperature values and pressure occurs at the pace set by the thickness of the board and what type of wood is being dried at the moment. There is a significant difference between the pressure inside the beam itself and the external pressure. Next, moisture is squeezed out of the timber due to the pressure difference. Further, due to the temperature difference, the surface of the board is cooled. And after that the device begins to function as vacuum chamber standard design with a slight difference in intensity (due to the use of higher temperature values). During the process, condensate appears, for which it is provided automatic system plum. Moisture is released when it reaches a certain volume; the pressure in the drying chamber decreases, first to atmospheric level, and then even lower. At this time, no energy is expended to create a rarefied state. Wednesday, technological process from this moment it flows according to classical thermodynamic laws. The equilibrium moisture content of the drying agent is maintained, which is in accordance with the specified final value of the percentage of wood moisture content. Conditioning is in progress: humidity is distributed evenly both within the scale of one timber and the total volume of lumber.
The wood harvesting process includes a drying operation. It prevents future defects and damage to the material. The procedure takes place in a special chamber. Any logging enterprise cannot do without it. Vacuum drying of wood is most often used. It has a number of advantages over other methods. For example, a short time process, uniform processing of all material and ease of installation and dismantling of the installation.
- Wood drying technology
- Vacuum drying
- We build a dryer with our own hands
A tree is a living organism. Like other organic compounds, it contains water. Freshly cut wood has a moisture content of more than 30%. To use it in the future for construction needs or making crafts, excess moisture needs to be removed. The excess water in the material may vary. Its standards depend on where the wood is planned to be used. For the manufacture of musical instruments, sports equipment and parquet, humidity is set at 6-8%. If the raw material will be subjected to further processing, then it is enough to leave 20% moisture in it. For the manufacture of building structures and finishing materials the parameter is controlled at the level of 8-15%.
Wood drying technology
Vacuum drying
The wood drying process consists of several stages. First, it is evaporated from the surface of the material, and then from its interior. Thin places dry out first, then moisture moves to them from thicker layers. If the process is disrupted, the thin layers begin to shift and the material is destroyed. To prevent this from happening, the workpieces are processed special mixture. It is made from drying oil and chalk. The end parts of the workpieces are treated with the resulting composition. They usually always have the shape of an equilateral geometric figure.
Accelerated drying mode is distinguishing feature vacuum drying chamber. It is known that water begins to evaporate when it boils. A very low pressure is created in the chamber. This allows water to boil at lower temperatures than normal. This way the process time is significantly reduced.
Another significant advantage is that vacuum drying significantly saves energy. Heating occurs by contact method. Temperature inside chambers and pressure are adjusted automatically. A vacuum is maintained in the chamber at 0.95 MPa. It ensures the heat and mass transfer process. Moisture is released from wood in the form of steam. After drying, raw materials are obtained with a given level of humidity. During the process, it completely retains its structure - it does not collapse.
This drying eliminates the use of fans. Humidification systems are also not needed. Neither dry nor wet bulb thermometers are used in the chambers. Humidity sensors are installed inside. They are controlled from outside. The entire control system is usually located in a separate vestibule.
Vacuum installations are often used for processing expensive types of raw materials: wenge, oak, rosewood, teak, angera. They use a heating element convector type. The maximum temperature in the chamber is +65 degrees. However, the process of moisture evaporation begins already at 45.5 degrees. The process completely eliminates the impact of high temperatures. Wood is practically not destroyed.
All the structural changes that accompany drying occur inside the tree. First, the moisture evaporates from the surface, then from the inside it approaches the surface again, and so on, up to 250 times over the entire time. Over the entire surface of the raw material, a humidity difference of 0.5-1.5% is allowed. Here are some indicators at which vacuum drying works:
We build a dryer with our own hands
An entrepreneur cannot always buy expensive equipment and use vacuum technology. For starters there are more simple methods.Do-it-yourself wood drying also occurs in drying chambers. To arrange it you will need the room itself, good insulation and a fan.
The design of the drying chamber with your own hands assumes that one wall and ceiling will be made of reinforced concrete. The remaining elements can be made of wood. The walls are insulated with polystyrene foam, lined with clapboard and covered with foil. Penofol can be used as a reflective material. It also reflects heat well and helps keep it inside the camera.
Mobile drying chamber.
Next, the heating device is installed. The most commonly used heating radiator. Its power should allow you to heat water to 65-90 degrees. The entire system is mounted separately from other heating circuits. It must work constantly, regardless of the time of year. Electric and gas appliances are often used. A fan is necessary to distribute air evenly in the chamber. Without this, it is impossible to dry the material evenly with your own hands.
It will also be necessary to build a system for loading lumber into the chamber. They are usually large in size and quite heavy. It is convenient to load boards on trolleys moving on rails or with a forklift. Inside the chamber, the material is placed on shelves or simply on the floor. It is also necessary to install control devices over the process, which will be carried out with your own hands. Without this, it is impossible to properly dry the wood so that it later has a marketable appearance and its inherent properties.
When building a drying chamber with your own hands, you need to adhere to the following rules:
When building a dryer with your own hands, the main thing is to ensure that the parameters required by the technology are maintained within it. The materials and equipment that will be used do not matter. Drying the wood in such a chamber, built with your own hands, will take from one to two weeks.
There are more advantages to this method. The use of vacuum drying allows you to avoid destruction of lumber, cracking, warping or other possible defects. In this case, a piece of wood will dry evenly, regardless of its thickness and length. This will take relatively less time, because the evaporation of moisture from wood in a rarefied environment occurs very quickly.
The equipment necessary for this is easy to transport and install, so it can be used in a variety of places, even directly in deforestation.
However, vacuum drying equipment is expensive, so small businesses and households can almost never afford it. Despite the small volume of the chambers (up to 10 cubic meters), the device consumes a lot of electricity. Perhaps this is the extent of its shortcomings.
Professional drying
The body of the professional wood drying chamber is made of stainless steel. For complete sealing, its top is covered with elastic rubber, framed in a metal frame. Sensors are installed inside to measure humidity.
A specialist controls the camera from the outside - the equipment necessary for this is placed in a separate vestibule. It is imperative to have a vacuum pump with enough power to pump out air and accumulated condensate.
Used for warming up aluminum radiators(in the form of plates) with water, which is heated using a boiler outside the chamber. Due to the absence of complex elements, such a machine is easy to operate.
Temperature and vacuum sensors are used to control the process. If something goes wrong, the specialist will track it based on the readings on the monitor.
But professional equipment is expensive - for a medium-sized camera you will have to pay from 3 million rubles. But it copes with raw wood in just two weeks, while with natural drying wood takes years to dry.
The specific drying time depends on the type and condition of the wood:
- boards made from freshly cut oak will dry for about a month, and freshly cut and thin-cut boards will dry for 15 days;
- wet (30%) Oak planks dried for 16 days, but in the thin version (25 mm) - a little more than a week;
- boards made from freshly cut pine take 8 days to dry, and with less humidity (30%) – only 6 days;
- building timber with dimensions less than 150 x 200 mm and a humidity of 65% will dry in 12 days, but thick types (200 x 300 mm) - approximately 21 days.
Time also varies due to differences in instrument settings for different breeds. Some breeds are hardy, while others should be treated gently, gradually, slowly.
Operation of a vacuum dryer
Vacuum drying of wood is divided into several stages. First, the wood is loaded inside the chamber. In this case, lumber is placed in layers between aluminum plates for heating. The specialist adjusts the drying parameters (temperature and pressure). This is necessary to work with different types of wood, after which you can turn on the device. When drying, the pressure is maintained at the same level, but the temperature can vary.
Note! During the warm-up stage, normal pressure is used and the vacuum pump is turned off. This is necessary to prevent defects from occurring.
When wood is heated to required temperature, include vacuum pump. It removes air from the drying chamber, thereby creating the required pressure. Moisture in wood moves from the center to the outer layers. Since this wets the material, use additional funds not required. Uniform distribution of moisture saves the wood from damage.
Moisture released to the surface of the material evaporates due to high temperature, settles on the walls of the housing and is removed by a pump.
The vacuum environment accelerates this process, because evaporation begins at a temperature of 40 degrees - this would not happen at normal pressure. The air surrounding the wood is never heated to a temperature exceeding 70 degrees. When pumped out, the upper rubber coating of the chamber is pulled inward and presses on the boards, creating a kind of press.
The final stage is conditioning. It is used only after the wood reaches the required moisture content. Heating is stopped, but the vacuum pump is not turned off. The wood gradually cools down, continuing to be under pressure, which is necessary to prevent changes in the shape of the material. When the temperature reaches room temperature, the pump is turned off and the wood is removed from the device.
Do-it-yourself room equipment
A DIY vacuum dryer for wood will cost less than buying it professional device. To do this, you will need to select a chamber and equip it with a heat source and a fan.
Using inexpensive ventilation instead of powerful pump– the main point of saving. Therefore, it is better to install the unit in a spacious room. It must be ventilated so that the air inside the housing can be constantly renewed, covered and sufficiently dry, otherwise the tree may become infected with mold or other diseases.
Camera
Most a good option housing for - iron conveyor. It is cheaper to use a used one (they are actively used in railway), but you will have to worry about its cleanliness.
A container for sea transportation is suitable for the job; you just need to look for a more airtight model. You can also use old scrap metal and weld the camera yourself. This is the most economical option.
To save internal heat The walls must be insulated with foam plastic and trimmed with clapboard. It is better to purchase a special insulating material for reflection, but you can use foil or penofol, with the second option being preferable.
Equipment
When the chamber is ready, proceed to assembling and installing the heating device and vacuum pump. Heating system dryers must be installed separately from the general heating circuit, because it must function stably and independently. Select a radiator capable of heating water to 65-90 degrees.
Important! To ensure that the heat is distributed evenly during drying, you will need to install a fan.
This is a mandatory step because uneven heating spoils the quality of wood. When constructing dryers yourself, great attention is paid to fire safety.
To make loading wood easier, a loading system is needed. So, you can use trolleys on rails or a forklift. Raw materials can be dried either on shelves or directly on the floor. If the safety of wood is important, then it is necessary to install temperature sensors, which will help control the process. This is especially important for expensive wood species. If the structure is built correctly, the temperature in the chamber will change evenly.