Optimal timber drying conditions at the Korkeakoski Sawmill

Vaisala’s humidity and temperature measurement probes help the sawmill to minimize the drying time for timber goods. The UPM-Kymmene Korkeakoski sawmill in Finland produces WISA-Wood standard sawn timber and WISA-Plus special sawn timber, mainly for big industrial end users in construction and the furniture and joinery industry. UPM is a global forest products group with core businesses in printing papers, specialty papers, label materials and wood products. In its main product areas, UPM is a leading manufacturer in all key markets.

Mikko Huttunen works as an Electronics and Automation Engineer at the Korkeakoski sawmill. “I am responsible for all electronics and automation matters at the sawmill, as well as the related procurement. I also participate in different development projects,” he says.

Carefully controlled drying chambers

After timber is brought to the sawmill, it is typically sawn up into planks. The planks are then dried to reach the desired humidity level in a special chamber. It is very important that the drying takes place evenly and under carefully controlled conditions, to ensure high quality of the end product. The drying process takes over a week, depending on the type of timber.

The Korkeakoski sawmill relies on the Vaisala HUMICAP® Humidity and Temperature Transmitter Series HMT330 to achieve optimal timber drying conditions at their facilities. Mikko Huttunen explains that “In summer 2007, Vaisala helped us to further develop our humidity and temperature measurement systems,” and points out that Vaisala also supplies the sawmill with services and spare parts.

In order to run efficiently, the Korkeakoski sawmill seeks to minimize the drying time for timber goods. Therefore the drying temperatures must be very high, which creates very specific requirements for the humidity conditions in the chambers. “The correct temperature-humidity ratio is essential to ensure the timber doesn’t twist or crack,” explains Huttunen.

Installation carried out in cooperation

The humidity and temperature transmitters’ measurement probes were installed inside the drying chambers, whereas the electronics and housing are outside the chambers. The information transmitted by the probes is sent to process control, which in turn controls the ventilation and temperature. “We developed the ideal installation method together with Vaisala,” notes Huttunen.

The article was first published in Vaisala News 179/2009