WOODDRYER SYSTEM

We are a kiln-direct.com partner and
suggest you visit this site for kiln equipment and controllers,
if you are visiting from outside Northern Europe. .

Wooddryer System Kiln Equipment.

Who is Wooddryer System. - The Wooddryer advantage.

How a Kiln Dries Lumber. - Why Kiln Dry Lumber. - When and Why Kiln can be Profitable.

Build your own kiln using
Wooddryer Panel System.

Our original format for Wooddryer System web site.
This site has proven to be a valuable source of information and new ideas.

Table of Contents:

Welcome to our Web-Site.

Let us welcome you and give you a short introduction to Wooddryer System and our Web-Site.

Wooddryer Interval System.

A description of the principles found in the Wooddryer Interval System and how it will help you produce a better product.

Wooddryer Control System.

A short look at our different types of control systems from the latest technology to the no-frill systems for smaller kilns.

Wooddryer Link System.

Our new top of the line multi-kiln control system based on the latest technology with new innovations and features not found on other kiln control systems.

Wooddryer Kiln Design.

Wooddryer System kilns are based on a common sense design. This page will tell you how and why our design is better.

Building a Kiln?

This page will give you an idea of how we help companies, like yours, get the best value by working together with your local contractors and on-site personnel.

Wooddryer Kiln Construction.

Wooddryer System builds kilns in all the major types of kiln constructions.

Rebuilding Your Existing Kiln

We can help you turn your existing kiln into a 100% up-to-date drying system.

Wooddryer Predrying System.

See how we have designed a load divided predrying system which allows you to load different species and thicknesses in the same predryer building.

Wooddryer Fan Shed System

This is one of our newest products. Its unique design and controls allow for precise control of the fan shed and the drying rate of the lumber.

Heat Recovery System for the Kiln Exhaust.

A heat recovery on the kiln will save you between 20% to 40% of the heat requirements in the kiln, thereby reducing the cost of drying significantly.

Wooddryer Concrete Steam Chambers.

We have two decades of experience in constructing steam chambers and advising companies how to steam for color or how to chock-steam to reduce stain.

Wood Waste Heating Systems.

Wooddryer System has installed wood waste heating system for delivering hot water or steam to our kilns.

Our Line of Small Kilns.

We have developed a line of small package kilns starting at 25 m3 (12.500 bf) loading capacity.

Wooddryer System is represented by:

                  Niels Jorgensen Company, Inc.
                  P.O. Box 159
                  414 Progress Drive
                  Burgaw, NC 28425.
                  United States of America.
                  Phone: 1 910 259 1624
                  Fax  : 1 910 259 1625
                  Email: wooddy@njc-usa.com

Dear Visitor:

Welcome to our Web-site and let us thank you for your interest in Wooddryer System. We look forward to showing you our line of products and the reason why we consider ourselves among the leading kiln manufacturers in the world with installation in the United States, East and West Europe, Russia, Baltic countries, Asia, and Africa.

Wooddryer System builds kilns with a loading capacity between 25 m3 (12,500 bf.) and 210 m3 (90,000 bf.). We design kilns in all the major types of kiln constructions:

• Pre-cast Concrete.
• Masonry with Aluminum roof construction.
• Aluminum/Stainless steel panel construction (normally for turn-key).
• 100% Wood constructed kiln chamber with an inside aluminum vapor barrier (exceptionally well suited for smaller installation).

During the last decade our research and development have been concentrated on making our systems more energy efficient and user friendly. Our new multi-kiln control system WOODDRYER LINK SYSTEM is based on the lastest technology in kiln controls with new and bold innovations. It has features for reducing energy cost, calculating your drying cost per m3 (mbf), remote access, Windows based PC software, and much more.

We look forward to showing you how we build turn-key kiln facilities or how we help companies, like yours, build their own kilns by using local contractors, on-site personnel, and our know-how and kiln equipment package.

We have designed this Web-site to be a learning and informative experience. If you have questions, need more information, or have comments about our Web-site, please do not hesitate to contact us.

Niels Jorgensen.
President (USA).

We at Wooddryer System are continuously developing our line of controllers for kilns, steam chambers, fan shed, predryers, etc. We have not only developed these controllers to serve the individual drying methods, but also gone the extra step of integrating the complete line of controllers into our WOODDRYER LINK SYSTEM which is a controller network based on a standard computer running windows.

The following controllers are currently available:

Wooddryer Interval System Controllers

There are two general types of interval controllers. One is normally installed on hardwood kilns which mainly dry medium to slow drying lumber; whereas, the second is a interval controller modified for pine and faster drying hardwood species. The second controller still takes advantage of the interval system, but allows for more exhaust.

Wooddryer Wet/Dry bulb controllers (Standard controller)

The wet/dry bulb refers to the standard operation where the kiln operator dictates the kiln climate. Although we say wet/dry bulb, we can also supply this type of controller with temperature and relative humidity sensors.
The PLC version is fully prepared for linking to our kiln controller network; however, we do offer a much less expensive unit with simple on/off controls together with a 6" graph.

Wooddryer Steam Controller

This controller is also based on an industrial PLC and has a level of flexibility and array features we have not seen on any other steam controller. We have incorporated over a decade of knowledge and combined it with proven technology. This unit can be linked to the kiln controller network where the operator can store multiple steam programs to insure a specific customer or product group always get the color/steam process needed.

Wooddryer Fan shed Controllers

This controller has more than just your standard on/off controls. First, each controller can operate and adjust four fan shed sections individually. Secondly, they can either adjust the drying speed using the interval system or be directly connected to a frequency motor control. The drying speed can then be fine tuned based on the outside temperature and relative humidity. In addition, when the system is linked to the computer network, we can add several extra energy saving features and record keeping.

Wooddryer Predryer Controllers

These controllers are similar to the fan shed controllers in the features they offer. Each controller can operate three individual predryer sections and general conditions in the "warehouse". Each section can be operated individually and uses a relative humidity sensor to optimize the drying rate.

Wooddryer Boiler Controllers

Currently under development.

All Wooddryer System controllers are industrial PLC based. This makes them very flexible and enables us to customize a controller to a customers specific need. In addition, the flexibility found in the PLC design extends all the way to our software and computer network.

Wooddryer Kiln Design.

Air Circulation:

We have moved the main fan section closer to the back side of the chamber. By using a special fan blade, we can increase the air velocity and create a vacuum behind the lumber. This vacuum pulls the air through the packs instead of blowing it, creating a much more even air flow, resulting in both better and faster drying. Main fans are reversed to limit moisture spread throughout the kiln charge.

For additional information on air circulation and main fans please choose one of the links below:

Wooddryer System main fan specification sheet.
Wooddryer System main fan section (header) specification sheet.
General information: How to compare main fan and their performance.
General information: How a kiln controls the drying climate/conditions including how air flow influences the drying rate.

Back to kiln design picture.

Exhaust System:

The biggest advantage of our exhaust system is the energy savings. By locating the exhaust system in the lower part of the back wall, the air with the highest humidity and lowest temperature (or in other words, the air with the least drying forces) is expelled. Just compare the temperature of the exhaust versus the traditional design on the drawing above.

For additional information on venting and exhaust please choose one of the links below:

Wooddryer System exhaust fans specification sheet.
Wooddryer System electric louvers specification sheet.
Wooddryer System gravity based louvers (normally used in front of exhaust fan) specification sheet.
Wooddryer System heat recovery system specification sheet.
General information: Venting in a kiln.
General information: How a kiln controls the drying climate/conditions.

Back to kiln design picture.

Heating Coils:

We prefer small heat units with a fan positioned behind the unit. They are easier to install, occupying less space, and improving air circulation. They can be used with either hot water or steam. A hot water system requires a lower investment, less operating, no chemical treatment, and lower future maintenance costs.

For additional information on heating in a kiln please choose one of the links below:

No specification sheet is currently available for hotwater or steam heat units yet, but our product line does include these. (100% stainless steel construction with aluminum fins).
Wooddryer System LP or natural gas heat unit chamber specification sheet.
General information: How to compare heating systems in kilns and their performance.
General information: How a kiln controls the drying climate/conditions including how temperature influences the drying rate.

Back to kiln design picture.

Conditioning:

We do not use steam for humidifying during the drying process, as our control system relies on the water evaporating from the lumber itself. Adding water or steam to a drying process is, in our opinion, a waste of energy. For conditioning we use fine water spray nozzles. This prevents the wetbulb from chasing the drybulb and is gentler on the lumber, but takes slightly longer.

We do carry valves and spray nozzles for humidifying/conditioning the kiln. However specification sheets are not available yet.

Back to kiln design picture.

Moveable Between-Deck:

Instead of baffles, we use a heavy duty tarp system which is lowered down on top of the lumber. This improves the air flow and is much simpler to install than a regular aluminum between-deck with baffles. (We do on occasion install a fixed between-deck upon customer's request).

For additional information on false ceiling/moveable between deck/baffling please choose one of the links below:

Wooddryer System moveable between deck specification sheet.
General information: Venting in a kiln.

Back to kiln design picture.

Main Door System:

Our main door systems are designed based upon the "lift and slide" principle. The door is made in one large plate without cold conductors, using 100mm/4" stainless steel foam panels. This door design prevents the water from condensing on the inside of the kiln, since there are no thermal conductors. We believe our kiln doors are the most energy efficient in the industry.

For additional information on our door system please choose one of the links below:

Wooddryer System all stainless steel kiln door design.
Wooddryer System "do it yourself" kiln door design.
General information: What makes a quality kiln door.

Back to kiln design picture.

Traditional Exhaust:

Our exhaust system has several advantages over the traditional exhaust design found on a majority of kiln designs. A traditional vent system is located in the top of a kiln in the front and back. On the drawing above, we demonstrate the differece between exhausting the air before (traditional exhaust) and after it has passed through the lumber.
The exhausted air is cooler and has a higher RH% with our system (which means less energy waste) and it gives you the ability to dry lumber at lower temperatures . . .even in the warmer climates.

For additional information on venting and exhaust please choose one of the links below:

Wooddryer System exhaust fans specification sheet.
Wooddryer System electric louvers specification sheet.
Wooddryer System gravity based louvers (normally used in front of exhaust fan) specification sheet.
General information: Venting in a kiln.
General information: How a kiln controls the drying climate/conditions.

Back to kiln design picture.

Although we do offer turn-key projects, we normally prefer to build and install the kilns in close cooporation with your local contractors and your on-site personnel. By utilizing local labor, you can save substantially on your initial investment (providing the project is planned and organized correctly). Our major function is to guide you through the building process by providing you with the know-how needed, detailed drawings, building meeting, and a kiln eqiupment package.

We have made a little example of how a kiln project can come together. This example is of a plan for a masonry constructed kiln.

1. We evaulate the potential kiln project together. We will discuss logistical matter, loading capacities, potential placement, etc.. Based on this information we will make a proposal with preliminary drawings, details, pricing.
2. When the plans have been accepted and the order placed, we will make a new set of exact drawings with any changes you may have requested. The new set of drawings are detailed, and they include drawing and instructions for the installation of the kiln equipment.
3. A building meeting is arranged where you, your contractors, on-site personnel, and ourselves get together to discuss and plan the upcoming kiln project. We discuss time table, details, and answer any questions.
4. The building contractor makes final building drawings (based on our drawings and suggestions) in accordance with local building codes. We must approve the new drawings. This allows us to catch any small detail which requires revision.
5. Concrete foundation and floor is poured, minimum 6" high strength reinforced concrete floor with vapor barrier. Insulation is optional.
6. Masonry walls are built on the concrete foundation. A concrete cap is built on top of masonry blocks. This cap seals the top of block wall from moisture and is designed for easy installation of roof construction.
7. Stainless steel or aluminium roof construction is installed per our drawings and suggestions. It is important to use blocks which are water repelling. If neither stainless steel or aluminum construction is suitable you can use steel or wood construction (see under wood constructed kilns).
8. Inside of kilns are coated twice with a water repelling barrier and twice with Silver-Liner, tar coating, or similar kiln sealant..
9. Kiln equipment is installed per our drawings and instructions. This can be done by your on-site personnel or a local contractor.
10. Hot water heating system is installed per our drawings and instructions. This should be done by a local contractor.
11. Electrical installation is performed per our instructions. This can be done by a local electrician or your on-site personnel.
12. Main door is installed; we will come and supervise installation. We will need one or two helpers and some fork lift service.
13. We will check installation, perform start-up procedure, and instruct your kiln operator.

We will normally come and inspect the progess of the construction and installation 2 to 4 times, depending on the size and location. In addition, we do have the ability to provide a supervisor/leadman, which we can send out to help with the installation or construction for a reasonable weekly price.

Each kiln project is different, and the above is meant to give you an idea how we help you build you own kiln in cooporation with Wooddryer System.

There are four major type of kiln constructions:

• Pre-cast concrete construction.
• Masonry with an aluminum roof construction.
• Aluminum/stainless steel panel construction.
• 100% wood constructed kiln with an inside aluminum vapor barrier.

Each type of construction has its advantages and disadvantages, but there are certain criteria which are common for all kilns.

The building for a drying chamber must first and foremost be air-tight, well insulated, and with as few cold conductors as possible. The building is normally done with pre-cast concrete, masonry blocks, wood construction, alu-sandwich panels or similar materials.

We require that a separate control room is built to house the Wooddryer Control System and other electrical installations associated with the kiln(s).

The building will normally be constructed by your local contractors per our directions and drawings. We will meet with the contractors, discuss your specific needs, and suggest the building methods and materials we consider best suited for the specific project.

If you should require a turnkey project, we will provide a complete construction team. Our method uses 3" aluminum or stainless steel sandwich panels over an inside steel construction. We find a glue-laminated front for the lift and slide door system the optimum. You must prepare the foundation, concrete floor, and ensure that electricity and heating are supplied according to our specifications.

This is the most durable and heavy duty of all the different kiln constructions. The walls of the kiln are constructed in 12" thick pre-cast concrete elements, which are raised and set into place to make an extremely solid wall.

The concrete elements have 3" insulation inside the concrete for maximum energy efficiency. The ceiling/roof is normally made from 8" thick solid pre-stressed concrete elements, after which 3" of foam board insulation is added before installing the aluminum profile roof panels.

After the building is finished, the concrete floor is poured. It has a vapor barrier, and insulation is optional.

Other than the strength of the building it does have a one significant advantages:

• It is the most quiet of the kiln constructions, especially with our lift and slide door system.

This kiln design is especially suitable for large kiln projects. For kiln site over 150 m3 (In the US 65,000 bf) loading capacity, the pre-cast concrete construction becomes a very good value, but it is seldom economical for smaller kiln setups.

Your local contractor will make the foundation, concrete floor, and masonry walls in accordance with our instructions and drawings. The walls are normally 30 cm or 12 inches thick and filled with insulation material in the middle. Before the installation of kiln equipment, the walls are sealed twice with Silver-Liner (a tar based sealant) or similar kiln sealant.

The roof construction is installed using rectangular tubing either in aluminum or steel. Steel is the best value, but needs a re-coating every 2 to 4 years. After the rectangular tubing has been installed, aluminum sheets are installed on top of rectangular tubing. The foam insulation boards are laid down next, and at last, the roof is finished with a thin profile aluminum or sheet metal panel.

This building process makes a very durable and long lasting kiln. We have found it most suitable for large/high capacity kilns.

Your local contractor will prepare the foundation, concrete floor with vapor barrier, and build a wood building according to the local building codes. The walls are made with 2x6 lumber and insulated with fiberglass insulation. The inside of the kiln is covered with regular 3/4" plywood with thin aluminum sheeting on top.

The outside is regular profile thin sheets of metal. The roof construction is also done in wood. The front construction is done with glue-laminated wood and a lift and slide door system.

This building method is especially suitable for smaller kilns and is very well insulated and economical to build.

We have well detailed manuals for this type of building construction. Our wood building method in based on a panel design. This design speeds construction by allowing you to do 80% to 90% of the work on ground level.

Here is a very short description of the building method.

1. First, the foundation is poured by local contractor.
2. Wall panels are built on the ground, normal size is 2450 mm (8'0") wide and 4900 mm high (18'0").
3. Panels are raised and installed on the footing of the foundation.
4. Roof trusses are installed.
5. Thin sheet metal roof panels are installed.
6. Insulation is installed in the walls and covered with thin sheet metal wall panel on the outside.
7. Just like the wall panels, the ceiling panels are constructed on the ground and raised into place one by one.
8. Kiln equipment is installed.
9. Electrical installation.
10. Main door system is installed.
11. Start-up procedure.

This wood panel building method has several advantages over the other kiln construction:

• Very well insulated with absolutely no thermal conductors.
• Very easy to install anywhere (especially newly industrialized countries).
• Building materials are available anywhere in the world.
• Faster and safer to build due to the fact most work is done on ground level.
• This wood panel design makes it easier than other kiln panel designs to disassemble and reinstall at a different location, making it extremely suitable for joint-venture projects around the world by eliminating the risk of losing the whole kiln. Just move them.
• Local contractors can easily repair any damage that might occur during usage.

We are place a value in this building construction, as we find it to be the best comprehensive value for smaller kiln facilities.

The Wooddryer Predrying System has been developed to solve the most common problems with standard built predriers. The most significant difference is the way we keep each load of lumber separate. This enables us to control the drying of each load (75 - 150 m3 or 30 - 60 mbf) of lumber by itself. By controlling each load separately, we can decrease the drying time to 14-20 days for 4/4 (26mm) Oak from fresh sawn to 24% MC. With a little more time, the wood can be dried to 18-20% MC in the predrier.

A predrier unit has a 4' deep fan section. These are placed against the walls of the predrier warehouse. Each load of lumber is placed in front of the fan section in the stacking area. The load will be surrounded by moveable tarp walls and between-deck. The advantage of the tarp system is that the warehouse can be used for either drying or storage.

The control system is based on the first phase of Wooddryer Interval System. This is where the control system will base the drying rate on the evaporation of water from the lumber itself. The control system will stop and start the main fan and exhaust fan when necessary to obtain the maximum drying rate.

The predrying warehouse must be an air tight and lightly insulated storage building/warehouse. For heat you can use steam, or we prefer hot water for heating units or floor heating. The temperature is kept at approximately 25 dg. F (85 dg. F) and a relative humidity of 75%. It is our experience that the energy cost of our predrying system is lower than the kilns, depending on the insulation of the predrying warehouse.

This is one of our newest products. We were not satisfied with the fact that nearly all existing fan sheds never took the outside weather into account. We designed our fan shed system to operate according to the relative humidity, time of year, and the kiln/yard manager's experience.

The fan shed has high air flow, and we adjust the drying rate by shutting the fans off. Example: The fans will run more often and longer when drying maple compared to oak; in addition, the higher the relative humidity is outside, the longer the fans run to compensate for the reduced drying by each cubic meter or cubic foot of air.

The design is actual quite traditional for a fan shed except for load divided tarp/curtain system. This system allows you to load oak and poplar into different sections, and the controls will treat each load according to the setting on the control box. Another unique feature which is built into this system gives it the ability to consume most of the electrical power during the off-peak or low cost hours of your electrical rate schedule.

Please press here for Wooddryer System Specification sheet for our fan sheds.

If there is a wish to save on the energy consumption, a heat recovery unit can be installed to reuse some of the energy from the exhaust. The heat recovery unit is well suited in cold climates. If the energy cost is high or fast drying species are involved, a heat recovery system may well be worth looking into.

One heat recovery unit can normally serve from 2 to 4 chambers depending on the size. The principle is based on an aluminum duct system that leads the exhaust air to a cross heat exchanger. This is where heat is transferred from the exhaust to the colder incoming air. The operation of the heat recovery unit is integrated into our Wooddryer Computer Control System .

In many cases a heat recovery unit is installed on new and old kilns. This prevents the added expense during an expansion of your existing boiler/heating system.

Wooddryer System has been involved in steam chamber building and operation for over a decade in Europe. There are general three methods of building a steam chamber: All stainless steel panel building, all concrete building, and utilizing a used refrigirated food container (these are normally insulated with inside stainless steel sheeting.

Wooddryer System makes a very advanced control system and components for an all stainless steel steam chamber.

The control system is designed to provide you with the same steaming result every time regardless of the temperature and condition of the lumber at start point. In addition, our control system has extra sensors and control features which enable you to achieve the same color every time or minimum color change with shock steaming. The steam controller is fully integrated into the Wooddryer Link System . The Link System helps you record the actual steam process and provides you with a database for developing schedules for different species and color requirements.

Wooddryer System Stainless Steel building construction is very well suited for steam chambers. We are able to provide you will all the building materials for a pre-engineered stainless steel structure with stainless steel inside paneling. Outside is insulated with 200mm/8" rockwool insulation and aluminum profile sheeting. This is not a cheap solution, but the it is most durable of cinstructions for large steam chambers.

Steaming for color:

Some wood species are steamed for a preset period of time to darken the color of the wood. The most common steamed specie in Europe is Beech and Walnut in the USA.

Shock steaming:

Shock steaming is mainly used to stop/kill enzymatic or coffee stain in species such as Beech wood. This steaming procedure is short and the steaming procedure is discontinued as soon as the inside temperature of the wood has reached 65 dg. C or 160 dg. F.

Shock steaming is also used on Oak. This procedure has shown to minimize degrade and shorten the drying time noticeably. Several of our European customers are currently shock steaming red and white oak for these reasons.

Basic requirements for lumber to be steam treated.

There are only a few requirements for lumber to be steamed. First, the lumber has to be sticked to obtain uniform steaming, and second, the lumber must be steamed within 24 - 36 hours after it was sawn. Air dried or partially air dried lumber should not be steamed, as it will increase the degrade.

We design and build Wooddryer System kilns in many different building constructions and with a loading capacity of 25 m3 to 210 m3 (12.500 bf to 90,000 bf.).

Press here to view a standard kiln proposal for a 25m3 / 12500 bf
kiln proposal with pricing on the kiln components and controllers.

Our 25 m3 or 12.500 bf kiln design gives you the following benefits:

1. They can be loaded with a small 4' forklift (1200mm).
2. Control system operates after the principles of the Wooddryer Interval System, meaning low temperature drying for best possible quality.
3. Same air velocity as our larger kilns.
4. Same venting capacity as our larger kilns.
5. Same heating capacity as our larger kilns.
6. Same energy saving design.
7. Hot water heating with wood waste, gas, or oil.

Why not less than 25 m3 (12.500 bf).

We found that below 25 m3 the investment in the kiln equipment remained the same. Therefore, it does not make sense to build a smaller kiln, since the investment per m3 of loading capacity increases greatly.

Can you dry half a load in a kiln?

Yes, this will not affect the kiln performance. But more importantly, you will have the options of drying larger loads when necessary and doing it efficiently.

Measurements for the USA.

  Building width :         19'
  Building depth :         28'     (without control room)
  Building height: approx. 12 - 16'               

  Stacking width:          17'8"
  Stacking depth:          20'
  Stacking height:          9'
  Stacking volume:  3,060 ft3 = approx.  12,500 bf

Loading capacity calculation is based on 26 mm or 
4/4 lumber and a normal loading pattern, and should 
be easily obtainable.

As with our larger kilns, we will sell the equipment and provide you with the know how to build your own kiln. The most common choice of building design for these small kilns is a wood constructed building with an inside aluminum vapor barrier. This is by far the most economical solution.