Production and assembly of timber drying kilns


About wood drying

Effective forestry is a combination of science and nature, which results in the acquisition of high-quality and durable wood. However, all wood species are harvested in a “green" condition, which is the term that we imagine when seeing the trees grow wild.

As trees form an autonomous aquatic and nutrient system, it is clear that in the outer part moisture level is higher than in the core. Outer part distributes water through the tree, whereas the core or internal wood absorbs oils, resins, tannins and other substances. This makes the inner part more durable with moisture and requires longer drying time than the outer layer of the wood - depending on the tree species, it will affect the process of the drying.

Wood moisture content (MC) is calculated according to the formula: ((Weight ”green” Timber - Weight Dry Timber) / Weight Dry Timber)) x 100%

Drying the outer part of the wood too quickly results in internal stresses leading to cracking of the wood, so we use a spraying system to spray the outer layers of the wood without causing cracks.

Wood is undergoing a dynamic exchange between the wood itself and the surrounding air. When the relative humidity (RH) in the air increases, the wood absorbs moisture from the air; when the RH falls, the tree releases moisture in the air. This is natural, and it occurs throughout the life of a wooden product, even after it has been cut and dried in dry condition.

The wood resistance and performance key is the appropriate drying of the timber to the optimal moisture content, depending on the conditions of use of the finished product.

The cost of the drying process depends on many conditions: the drying kiln model (size and technical configuration); boiler type, capacity; the species of drying wood, the size, the initial moisture, the location of the timber, as well as the surrounding natural conditions. Estimated costs can be calculated by adding the electricity and heat consumed by the kiln and the boiler, multiplying it by hour with the number of hours of the drying cycle.
In the technical configuration of the drying, it is necessary to find the right balance between the optimum power and the cost of drying the drying cycle. Technical components are selected to make a significant contribution to the quality of the technical performance, its durability in service and the expected post-warranty service costs.
The structure of the drying kiln is a separate and very important section. We often encounter complaints of old kilns, whose operating costs are several times higher than the modern ones. This is due to errors in their construction or inappropriate performance evaluation. Drying kiln is not an ordinary building or heated hangar - its structure faces many environmental challenges during operation, they need to be adequately evaluated and technically resolved accordingly.

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info@balticdry.lv