Wood Drying Kiln Manufacturer Supplier

shuowei provides wood drying kiln manufacturing services using state-of-the-art technology. Make sure the product is more stable in use.

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ShuoWei wood drying kiln

There are many methods for wood drying in the wood industry. Such as air drying, solar kiln, conventional kiln, lumber vacuum kiln, and HF vacuum wood dryer kiln.

High frequency vacuum wood drying kiln is high frequency medium heating. It is also called radio frequency heating. It is the most advanced heating method in the wood drying industry.

What’s The Difference Between HF Vacuum Wood Dryer With Vacuum Kiln


Wood drying kiln series

We are a professional manufacturer of kiln dried wood equipment. We can provide all kinds of wood drying equipment such as: Small wood drying kiln, wood drying kiln, high frequency vacuum wood drying machine, etc. We can also provide customized services according to your needs.

Capacity: 4.4 cubic meters per full load
External dimensions: 5400x1716x1809mm.
Timber cart dimensions: 4000x1100x1000mm.

Capacity:6.6 cubic meters per full load
Out Dimension:6500x1916x2006mm.
Timber Cart Size:5000x1200x1100mm.

Capacity:8.64 cubic meters per full load
Out Dimension:7600x2000x2090mm. 
Timber Cart Size:6000x1200x1200mm.

Capacity:10.08 cubic meters per full load 
Out Dimension:8600x2000x2090mm
Timber Cart Size:7000x1200x1200mm

Capacity:12.48 cubic meters per full load 
Out Dimension:9600x2000x2090mm
Timber Cart Size:8000x1300x1200mm

Capacity:14.56 cubic meters per full load
Out Dimension:9600x2200x2090mm
Timber Cart Size:8000x1400x1300mm

Capacity:21.6 cubic meters per full load
Out Dimension:9600x2700x2300mm
Timber Cart Size:8000x1800x1500mm.

For the thick wood block it is take super long time to finish the drying process by conventional kiln.In order to save this problem, we developed the high frequency vacuum kiln for wood block.

The fresh peeling veneers, it’s only take 20-30 hours to finish the whole process of veneer drying by the high frequency veneer dryer.

Main Advantages Of High Frequency Vacuum Drying Technology

Working Principle & Process​

High-frequency waves can penetrate wood deeply and dry wood from core to wood surface wholly and uniformly from the ever beginning. Even thick wood can also be well heated. Meanwhile, under vacuum conditions, wood moisture can be boiled at 35-50 degrees and vaporize rapidly, which can save both time and energy. And low-temperature wood drying can guarantee wood quality to avoid the crack problem. The vacuum system will suck wood moisture out due to pressure difference which double increases wood drying speed. The result of the combination is that even more than 50cm thick wood can be dried by our high-frequency vacuum wood dryer machine with uniform moisture content within two weeks. Normally Drying time for one cycle is 7-12 days.

wood drying kiln's Key Advantages

1. Stable wood drying without defects

The wood is drying under vacuum conditions which allows the water to boil at a low temperature like 35℃,then it can be vaporized fast.Low-temperature drying solves the problems of wood cracking, deformation, and discoloration, especially for precious timber sensitive to temperature.

2. Fast wood drying

High-Frequency makes the wood heated from core to surface wholly and evenly, it will create a temperature gradient of internal high and external low and then vacuum pressure make water drain out very quickly. For the 8cm thick Africa rosewood from 40-50% moisture content to reach 8-10% moisture content, it only take 7 days.

3. High-quality wood drying result

High-frequency vacuum wood dryer machine is equipped with hydraulic pressure system on the top, the hydraulic pressure system supply 4-6 tons pressure on the wood stacking to prevent wood deforming and bending. We use stainless steel 304 to make the pressure plate.

4. Easy operation

PLC control system and Pneumatic system make the machine easy to operate. It is a kind of automatic drying so there is no need for staff on duty during the drying process.

5. High-quality high frequency vacuum wood dryer machine

Our high-frequency vacuum wood dryer machine is made of stainless steel to avoid corrosion and rust. 

6. Killing Insects & eggs

Insects (eggs) and fungus will be killed during the drying process thoroughly, there will be no need for chemical treatments anymore. 

How a wood drying kiln works

Our kiln also adopts vacuum dehydration technology. 
The stainless steel vacuum pump can make the vacuum oven reach -0.093Mpa condition. 
The vacuum condition is to let let water vaporized in low temperature below 55 ℃,At the same time, vacuum can also suck the wood moisture out. 
The machine cooling system will separate the hot air and hot water out, then cool them and release them out.  
Wood is drying under a vacuum and wet condition at low temperature. 
That will ensure wood is no cracks and keep the wood nature color.
High frequency vacuum dry kiln is the best choice to thick table top, veneer, thick slab, expensive wood, hardwood, veneer, beam and etc.

Main components of wood drying kiln

1. High frequency generator is the one of the core technologies in SW kilns, the main function is transfer electricity into high frequency power. It adopts the PLC system for better control

2. Square shape vacuum oven chamber is Shuowei’s patent design,it is easier for the workers to stack wood and make the best use of room.      

3.The auto cooling system consists of cooling tower and External condensers.
The function is to condensate hot vapor and separate water from air to drain it out

4.There is hydraulic pressure system and stainless hydro-cylinders in the chamber, it could supply at most 6 tons pressure on the wood to keep it straight and flat.

5. There is an motor on timber feeding cart. It will save labor to load and unload the wood stacking.

6. Stainless steel vacuum pump and solenoid valve provide reliable support for the vacuum system, all pipes are made of 304 stainless steel, tough and corrosion-resistant.

Wood Drying Kiln Installation Video

Shuowei has been devoted deep into the vacuum wood drying field for over 30 year, we pay much attention on improving the operation and developing the designs.
This high frequency vacuum wood dryer adopts many technology to cut down the need of labor, it has a automatically timber cart which allows easy wood feeding, the high frequency heating makes it possible to do a dead stacking (no spacers), and you could leave the system working alone because the pneumatic valves there etc. All of these contribute to an advanced vacuum wood drying kiln, you deserve it.
Because the Integrated and modular design, this kiln is easy to install and it is of high reliability. The serious pandemic hit the world in 2019 and stopped the business travailing, since then we used videos and brochures to help clients assemble this kiln, Clear mark is there to guide the operation, and it proved to be workable, After all shuowei technicians will offer 7*24 on-line service for your any questions and training for free.
Shuowei focused on easier faster and higher quality wood drying solutions.

wood drying time chart

location Wood Species Wood Size Wood Density Initial Moisture Content Moisture Content After Drying Drying Time
Tanzania, Uganda Africa Mahogany Thickness50-70 mm Long1-6 Meters 0.75g/cm3 MC 40%-50% MC 8%-10% 5 Days
Indonesia Teak、Indonesian Pinewood、Indonesian Rosewood Thickness50-50 mm Long 2-3 Meters 0.7g/cm3 MC 40%-50% MC 8%-10% 4-5 Days
Iran Oak Wood Thickness 2-25 mm Long 1-3 Meters 0.63-0.79g/cm3 MC 40% MC 10% 4-5 Days
New York, USA Eastern Cottonwood Thickness70mm Long4000-5000mm Width600-1000mm 0.386g/cm3 MC 75% MC 8% 4 Days
New Zealand Pinus Radiata Thickness 50*50 mm Long 2-8 Meters 0.415 - 0.545 g/cm3 MC 100% MC 20% 4-5 Days
Thailand Burmese Teak Thickness 25mm 0.65g/cm3 MC 18-20% MC 10-12% 4 Days
UK Oak Wood Thickness 50*50 mm Long 2-3 Meters 0.63-0.79g/cm3 MC 85%-90% MC 18%-20% 8 Days

Helping you solve kiln-dried wood problems

Bending, cracking after drying process

Compared with conventional steam kiln, high frequency is kind of directly heating, In the electricity filed, wood will be heated both inside and outside at the same time, the vacuum technology allows the wood drying process is under an vacuum wet conditions and at a low temperature, which will ensure there is no cracks and keep the wood to be nature color. Meanwhile our machine is equipped with hydraulic system on the top, it can offer 6 tons pressure during whole drying process. That will ensure no bending there.

Long preparation and hard to control the drying quality

For the traditional drying kilns ,the preparation period is quite long before you can really dry the wood , the operation is complicated and wood drying quality is closely related to the workers, while for Shuowei products, we adopt simple structure and Integrated design which is easy to install, the clear and easy control board will ensure stable and reliable drying results with little request of operations.

Due to the long drying cycle, the funds cannot be turned over

Cash flow is very important for the company, especially in wood industry, the earlier you make wood to wood products, the faster you get money. As proved by the performances, HF vacuum dryer offer a significant reduction in drying times. it takes only one tenth time of the traditional ways, so Out-turn percentage of timber has increased, your cash flow is much healthier.

After-sales Service

  1. Provide users with important technical information for operation and maintenance. Combining with the network and remotely.
  2. Provide technical and business training for equipment installation, commissioning, operation, and maintenance. When necessary, experienced engineering and technical personnel could be sent to provide on-site technical services in time .
  3. After receiving the user’s complain of the quality problem , It is guaranteed to reply within 24 hours and provide a solution within 48 hours, and the service will not stop if the user is not satisfied with the solution
  4. Easy to install and start, taking only a few hours to get the program up and running  
  5. When used properly, machine parts are rarely damaged
  6. Lifetime after-sales service

Our Happy Clinets From 80+ Countries

Have more questions please contact us

wood drying kiln:The Ultimate Guide

When you cut down the tress, and get the wood slab from it, it is not ‘dead’ in some aspects, even without roots, the wood is ‘breathing’ in the air, it takes in or releases moisture based on the water content surrounding it. then there will be constant expanding and contracting for the wood. This is sometimes a factor that will be used to strengthen the joints but for most of the time it will cause some troubles for the finish looking and application.

A proper moisture content is important for the woodworking, you should be serious for this. So it become a very good question that, how dry does the wood need to be for woodworking?

To clear show this, we need first understand the Moisture Content, MC for short.

Moisture content or ranter water content is the water inside the wood, usually it is measured in percentage,but in the practice we need some special equipment to get this data, that is the moisture meters, Pin and pinless meters are the two main types of moisture meters. The principle of pin meters is the drier the wood, the more resistance to the electrical current, so it uses two pins to measure the resistance and change it to the readings of MC; meanwhile the pinless ones provides readings by the electromagnetic signal changes.

Then the question becomes what MC should the wood bear?

This requirement is varying because of the regions and applications, like in some wet areas the wood must be kiln or air-dried to a moisture level of 20% so to be used in fences, floors or some construction projects outdoors. Meanwhile if the wood are made into furniture indoor in some dry city, the wood must be dried to less than half of that, which is below 10%

In fact,because the water in the wood are divided into free water and bond water, and the air drying method could only dry the wood to an environment MC level, the most wood for wood working are kiln-dried, Shuowei vacuum drying kiln is one of the best drying methods.

It has a well sealed stainless steel chamber for the vacuum drying system, which allows the wood being dried at 35 ℃, it is better to keep the natural color and wood quality and then about the heating principles, this kiln adopts the high frequency technology and it creates a electrical field in the wood, thus the wood is heated evenly and directly, it is totally different from the traditional heat transfer method which is conducting heat from surface to core, and an advantage to this is, you could deadly stack(no spacer) the wood in the automatic timber cart, After all you will get the wood same quality as you put in, but dried, the drying circle will be within 8 days for 2” hardwood from over 50% Moisture Content (fresh cut ) to 8-10% MC. It  is really a fantastic machine Contact us for easier faster and higher quality wood drying solutions.

This is a very interesting questions when we are trying to get better turnover and healthier cash flow in the wood drying field.

What we need make clear firstly is that the wood drying is an indispensable process in the usage of wood sources, when you get the raw materials from the forest, the water content in these wood are as high as 60% or even 100% more, they are easy to deformation and prone to pests and fungi, And the cost to transport these wood will be much higher than the dried one because the transportation is priced by weight.

And Then comes the question of how to dry the wood? There are many existing ways, like air drying, kiln drying , vacuum drying, high frequency drying etc., they are all of different features and are applicable for different cases, different people will choose different methods for their purposes, but one thing that is always a big concern and easy to compare is the drying speed, just like the other products, the best production mechanism is that you could get the finish product quickly, sell it and get back the investment & interests.

What is the fastest way to dry wood? And how fast is it?

As of the nowadays technology, the high frequency drying or Microwave Drying is the fastest way to dry the wood,the working process will be like that High frequency generator generates electromagnetic fields between two electrodes through three phase alternating current where the wood are loaded, In this field, water molecules are polarized – rotated – heated by friction. The heated water then will be vaporized and comes out of the wood.

It is totally different from the traditional kilns, for which you need first heat the air or the metal plates and then conduct the heat to the wood, it is a direct heating methods which works on the water inside the wood.

Such heating method will greatly shorten the drying process, and it will only take several days to dry the green wood to wood with below 10% water content. When we are talking higher temperature and higher airspeed in the traditional kilns to faster the drying speed, this kind of high frequency drying already totally redefine the drying fast to days, which may takes weeks before.

Anyway, there maybe different need of wood drying, like for furniture and fences , the MC results needed are different, for woodwoking and firewood, the quality requirement are not the same, but in every aspect and work conditions, High frequency drying are the fastest wood drying methods, It’s an innate advantage.

Get in touch with Shuowei high frequency wood drying kilns! Our team are experts in wood drying applications. We understand the demand of the industry and need for easier faster and higher quality drying solutions.

1 Atmospheric dryness

That is, the wood pile is hidden on an open field or in a shed, the atmosphere is used as a heat and moisture transfer medium, and the heat of solar radiation is used to remove the moisture in the wood to achieve the purpose of drying. The advantages of atmospheric drying are: simple and easy, energy-saving, relatively economical, and can meet the requirements of air-drying materials. The disadvantage is that it is limited by natural conditions, the drying time is longer, the final moisture content is high, and the space is large. During the air drying, the wood is susceptible to bacteria and insects. At present, the use of simple air drying is gradually decreasing.

2 chamber dry

Refers to the method of drying wood by manually controlling the parameters of the drying medium in the drying room. According to the temperature of the drying medium, it can be divided into low-temperature room drying, conventional room drying, and high-temperature room drying. Appropriate room drying methods should be correctly selected according to the tree species, thickness, purpose and other conditions of the wood to be dried. The advantage of room drying is that the drying quality is good, the drying period is shorter than that of atmospheric drying, and the drying conditions can be adjusted flexibly. The disadvantage is that although the time is shorter than atmospheric drying, it also takes several months.

3 Vacuum drying

That is, the wood is dried in a closed container under negative pressure. According to the operation mode, it can be divided into two types: intermittent vacuum drying and continuous vacuum drying. Intermittent vacuum drying is carried out alternately according to two stages of normal pressure heating and negative pressure drying, heated with steam or hot water. Continuous vacuum drying is continuous heating and vacuum at the same time, heating with a hot plate or high-frequency electrolyte. The advantage is that the drying speed is fast and the drying quality is guaranteed. It is especially suitable for the drying of thick plates and square materials.

4High frequency vacuum drying

The wet wood is used as a dielectric and placed in a high-frequency electromagnetic field. Under the action of an alternating electromagnetic field, the water molecules in the wood vibrate continuously with the change of the electric field, friction generates heat, and the wood is dried. The application of high-frequency drying tends to be combined drying, such as high-frequency vacuum combined drying. The advantages of high-frequency vacuum drying are that the wood is heated uniformly inside and outside at the same time, the drying speed is very fast, the drying quality is good, and the natural color of the wood can be maintained.

Why do some wood products such as wooden doors, wooden floors and wooden furniture have quality problems such as cracking and deformation after they are sold? How to reduce the loss of these problems to wood enterprises?

After the production of wood products, the shape and material will not change. At this time, the key factors determining the internal quality of wood products are mainly wood moisture content and drying stress. Manufacturing enterprises need to correctly grasp the moisture content of wood products. When the wood products reach the equilibrium moisture content, the wood at this time is least likely to crack and deform. Dealers selling wood products should also test the moisture content of the products sold to master the quality status of the products sold. Select manufacturers with good product quality. All manufacturers who pay attention to product quality will test the moisture content of their products.

So what is the best moisture content for woodworking?

When wood is placed in a certain environment for a long enough time, its moisture content will tend to an equilibrium value, which is called the equilibrium moisture content EMC of the environment. When the moisture content of wood is higher than the equilibrium moisture content of the environment, the wood will expel moisture and shrink, on the contrary, it will absorb moisture and expand. For example, the annual average equilibrium moisture content in Guangzhou is 15.1%, while that in Beijing is 11.4%. Drying to 11% of the wood is suitable for Beijing and can be used in Guangzhou. It will absorb moisture, expand and deform. Therefore, wood drying should be appropriate, not the more dry the better. The requirements for wood moisture content are also different in different regions and different uses.

The equilibrium moisture content of wood is affected by atmospheric humidity, which varies from region to region. About 12% in the north, about 18% in the South and about 16% in Central China. The equilibrium moisture content of wood is of great significance in production. The moisture content of furniture, doors and windows, interior decoration and other materials must be dried below the equilibrium moisture content of the use area, otherwise the wood products will crack and deform.

High frequency vacuum wood dryer kiln is good machine to get quality kiln dried wood with low moisture content, welcome contact Mr.Carlos to talk more details about the vacuum wood drying or high frequency technology for wood drying.

Wood will crack if it is not careful in the process of drying wood, mainly due to internal cracking and surface cracking in the process of drying. What is the reason for these phenomena?

1. Internal Cracking

for thin plates with a thickness of less than one centimeter or by air drying, internal cracking will hardly occur. Internal cracking is formed after the surface cracking develops inward and the surface cracking is closed. There are also cases where there is no surface crack and only cracking occurs inside.

the internal crack of chord-wise wood occurs at the end of drying because the shrinkage of the inner layer along the width direction is greater than that of the surface. Internal cracking is closely related to drying temperature. Generally, the temperature of wood drying equipment at the initial stage of drying is low, that is, about 50 ℃, and it is difficult for surface cells to collapse. However, the inner layer of wood is heated for a long time under the condition of high moisture content. With the progress of drying, the drying temperature of wood drying equipment increases gradually, and the cell collapse increases. Therefore, most thick plates are prone to internal cracking due to the extension of internal heating time. In addition, if the dry wet bulb temperature difference is large at the initial stage of drying, the surface tensile stress will be large. In addition, if the internal cells collapse, it is also easy to produce internal cracking.

2. Surface Cracking

The reason for surface cracking is that the inner and outer layers of wood are unevenly dried, and the radial and chord directions are different

The difference in contraction is an important additional factor. When wood is dry, it is first steamed from the surface

When the moisture content of the surface layer decreases below the fiber saturation point, the surface wood opens

At this time, the moisture content of the adjacent inner wood is still above the fiber saturation point,

No shrinkage occurs. The shrinkage of surface wood is limited by the inner wood and cannot be harvested freely

Shrinkage results in internal stress in the wood: the surface wood is pulled and the inner wood is compressed.

The more intense the drying conditions, the greater the difference in moisture content between the inner and outer layers of wood, and the greater the internal stress

The bigger. If the tensile stress of the surface layer exceeds the transverse tensile strength of the wood, the wood structure

Torn, because the tensile strength of the tissue along the wood ray is lower than that of the adjacent wood fibers, Therefore, cracks first occur along the wood ray.

Treatment Measures To Prevent Wood Cracking

1. Mechanical crack prevention

Tie the end of the dry wood with iron wire, and force the wood not to expand or shrink by mechanical means such as an anti-crack ring and combined nail plate, so as to avoid wood cracking.

2. Improve the sawing method when making wood

Wood anisotropy. Under the same temperature and humidity change, the largest coefficient of wet expansion and dry shrinkage is in the chord direction, followed by the radial direction, and the longitudinal change is the smallest. Cracking should be reduced when sawing. In particular, the board with a pith core is prone to serious splitting during drying, which is caused by the difference between radial contraction and chord contraction near the pith core. The best way is to avoid making the board with a pith core when making wood.

3. High-frequency vacuum wood drying technology

High-frequency vacuum wood dryer kiln adopts high-frequency medium heating and vacuum dehydration technology.
High frequency is also called radio-frequency, it is a kind of direct heating.
The principle is using the wood as a medium, capacitor is a group between
two pieces of the metal plate. Then give them voltage, the electric field produced between the two plates. The water molecules between electrodes
will be polarized by the alternating magnetic field and move at a very high
speed rapidly. The impact and friction (billions of times per second) among
water molecules create heating in a very short time. It is a kind of direct
heating, This continuous effect let the whole wood-heated surface to core
wholly and uniformly. So the wood will shrink at the same time. That will avoid the wood surface cracking. That is also one of the reasons why the high-frequency vacuum machine is 10 times faster than a conventional wood drying kiln
Our kiln also adopts vacuum dehydration technology. The stainless steel
vacuum pump can make the vacuum oven reach -0.093Mpa condition. The
vacuum condition is to make water vaporize at a low temperature below 55 ℃, At
the same time, a vacuum can also suck the wood moisture out. The machine
cooling system will separate the hot air and hot water out, then cool them and
release them out. Wood is drying under a vacuum and in wet condition at a low
temperature. That will ensure wood won’t have internal cracks during the wood drying process.
If you have any questions about wood drying you can discuss them with us.


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Send us a message if you have any questions or request a quote. Our experts will give you a reply within 24 hours and help you select the right HF wooddryer you want.