Vacuum Kiln Plants

Fast drying of thick and valuable hardwoods.

It is all about cash flow … and here you thought it was about quality, color retention, speed and labor. Well it is, sort of.

Let us explain:

The reasons for using a vacuum kiln instead of a traditional forced heat kiln dryer are:

  • 3-5 times faster drying
  • 1/3 –1/2 the energy consumption of a conventional system per board foot.
  • Significantly higher drying quality over conventional drying.
  • High quality or gentler drying on the wood allows for the processing of much thicker dimensions and processing is less expensive.

So bottom line is that when you can turn around 6 loads when you normally would turn just one load…well you sell more and get paid faster – it is a simple as that!

Installation Pictures

Examples of Lumber used for Vacuum drying

Traditional Drying ……..

In modern kiln drying technology, there are two main principles in play: conventional and vacuum-drying kilns. In conventional kilns, the lumber is dried in a closed building by circulating hot air through the timber graphstack by controlling the temperature and relative humidity in the kiln chamber. One must ensure an even moisture extraction from the wood.

This process takes many weeks with a high cost of energy…and drying defects are common.

Versus Moldrup Vacuum Drying………

In order to reduce drying time and to improve the drying quality, the use of a continuous vacuum was invented, originally by Steen Moldrup back in the ’80s by drying in an atmosphere of super-heated steam under a vacuum.

How does this work and why is that important to you?

hallThe process begins with an initial vacuum where all the air from the timber and the chamber is pumped out. The vacuum lowers the boiling point of water to below 212 dgr F (100 C). Since boiling water (steam) moves faster through the wood than water by diffusion (as in traditional kilns), the Moldrup drying plants dries the same lumber 3-5 times FASTER than in a traditional kiln system. In order to transfer the heating energy to the lumber in a smaller chamber, we use heated plates. The plates are heated with hot water. Using an autoclave (Pressurized Cylinder) you have the advantage of not having any sharp points/corners – easier to maintain a tight environment (holding the vacuum) without the use of rubber membranes and other additional and foreign objects.

Moldrup drying plants are based on super-heated steam drying methodology and IWT (International Wood Technology, LLC) is owned by Moldrup and is from where we supply the plate-drying plant technology utilizing and offering the vacuum-drying advantages and principles.

We offer a full line of vacuum kilns from 2000 b.ft to 13,000 b.ft per charge with lease finance packages available for easy acquisition and purchase.

IWT Vacuum kilns