Text and photos: Gerd Ebner, Holzkurier

“We set very high standards for drying quality”

– The requirements for drying quality are very high for us. After all, we manufacture BSH and CLT lamellas primarily for our sister company, Mosser Leimholz. The very first OTC continuous kiln from Valutec achieved the target moisture content with only one percent variation, says Managing Director Martin Bruderhofer, who is responsible for both companies. – Our goals were the highest possible drying quality and high capacity – and both were achieved. Despite large variations in incoming moisture, we haven’t had a single complaint.

Satisfied with the project’s progress: Patrick Korn and Thomas Elsnigg from Mosser Holzindustrie (from left).

Fully automated drying around the clock

Production Manager Thomas Elsnigg is impressed by the performance of Valutec’s continuous kilns. Perhaps because he was not involved in the first investment, the Swedish technology first had to prove itself to him.

– In addition to the excellent drying quality of the lamellas, the even energy consumption is a major advantage for us. The buffer zones also provide logistical benefits, and both kilns run completely automatically even on weekends. Self-operating drying for up to 48 hours is possible, allowing us to maintain true 24/7 operation, he explains.
To enable long operation without staffing, Valutec built buffer zones for ten packages before and after each kiln. Together with eight traditional batch kilns, the two continuous kilns dry about 200,000 m³ per year – enough to handle the planned production increase in Wolfpassing for 2023–2024.

 

 

Optimal for large, uniform series

The Swedish OTC model was developed specifically for uniform dimensions and large volumes, up to 100,000 m³ per year. OTC stands for Optimized Two-stage Continuous, a two-stage continuous drying process.

This makes it ideal for the conditions in Wolfpassing, where Mosser processes highly uniform dimensions. In the first stage, drying begins at the fiber saturation point; in the second stage, the process continues evenly down to a target moisture level within ±1%.

– A uniform drying result gives us major advantages, emphasizes Elsnigg.

Stable energy consumption – no need for a separate heating plant

When the first kiln was put into operation in 2019, traditional drying technology would have required building a new heating plant to meet the capacity demand.

Now, despite increased production, energy consumption remains stable. The raw material is used efficiently thanks to consistent final moisture regardless of initial conditions.

– The timber also maintains its dimensions better, and the risk of cracking is minimal, says Elsnigg.
Labor input has also decreased: the forklift moves lumber directly from the saw line into the kiln, and the dried material is loaded straight onto trucks for transport to Randegg, about ten kilometers away, where BSH and CLT production takes place.

– We’re basically drying online – the lumber is dried, loaded, and transported directly to the next stage, explains Bruderhofer.

– The packages can be placed without any sensors – the process is fully automated. Fresh lumber is placed on the infeed conveyor, and 70 hours later, it’s ready at the outlet, adds Elsnigg.

Commissioned in less than a week

When the first kiln was installed, it took about a week to fine-tune the system – like learning to drive a new car. This time, things went much faster.

– The second kiln was commissioned in just three and a half days, and the process worked perfectly from the very first batch, says Project Manager Patrick Korn.
Both kilns have also been upgraded with Valutec’s latest control system, Valmatics 4.0, developed to meet Industry 4.0 standards.

– The drying process is simulated and optimized from start to finish, explains Eric Johansson, Marketing Manager at Valutec.

– The system automatically adapts based on capacity, quality, and energy consumption – exactly the factors most important to Mosser.

Self-adapting process

Valmatics 4.0 is integrated with production control via a workstation. The operator only needs to enter the moisture content in and out – the system takes care of the rest.

– Now the process adjusts itself according to the target values, explains Elsnigg.

– Previously, everything was preset, but now the kiln can decide on its own whether to move on to the next stage earlier or later.