Debarking needs at sawmills and/or plywood factories many times change during the lifecycle of a debarker. Purchasing a new machine is not necessary in all cases, instead modernizing the debarker may be an option to help increase the capacity or lengthen the life cycle of a machine and reduce maintenance costs.
The Swedish Södra is a large international forest industry group that manufactures cross-laminated timber, bioproducts, pulp and paper, and sawn timber, among other products. Södra has six softwood sawmills in Sweden and the production volume of the sawn wood in the mills is about 1.9 million m3 annually.
Södra is a long-term customer of Valon Kone. The first VK machines were supplied to the group’s sawmills in the late 1990’s and six VK debarkers are now operating in five Södra mills. Two of those machines are running at the Mönsterås sawmill.
Originally, Mönsterås had purchased two VK Combi debarkers with two debarking rotors and a hydraulic tool pressure in each. With two rotors they could reach a necessary feed speed level during the winter season. The hydraulic tool pressure was a closed pressure system. Meaning, when the tool pressure was needed to be changed, the rotor had to be stopped during the pressure adjustment. Also, since the closed system could not allow a tool pressure release, there was a need for an intermediate storage between the debarker and saw machine to empty the debarker when the saw line was stopped. “The original rotors at Mönsterås were worn out, as we had debarked about 70 million of logs during the 20 years they were in use. In addition, we needed to reduce our maintenance costs”, says Denis Halilkanovic, project manager from Södra Wood Mönsterås. “It was time to do something.”
As a solution, Valon Kone offered to change all original rotors with the latest VK technology. The new rotors are now equipped with a pneumatic tool pressure system and this allows machine operators to change the tool pressure remotely. In addition, the tool arms are equipped with an automatic opening function. When feeding to the saw line is stopped, the tool arms of the rotor open immediately, and logs can be stopped inside the debarker.
The new solution offers many advantages for Södra. “We can now increase the availability and degree of the saw line better. We have been able to reduce stopping times, as we can change the tool pressure from the control room. In addition, it means minor jams, as the debarking tools open automatically. There is no need to empty the debarker at each stop, as we had to do with old debarkers with a hydraulic tool pressure. And, this has improved the working circumstances as well,” continues Denis.
Due to the better tool coverage of VK air seal debarking rotors, the customer can now achieve the same capacity by debarking with one rotor, instead of two. The more robust construction of the air seal rotor means less maintenance. “We have been able to reduce our maintenance costs as well,” tells Denis.
“Södra has been very satisfied with the solution Valon Kone offered and our goal is to debark the next 10 to15 years with new rotors,” tells Denis. “The service we receive from Valon Kone AB, is very good, the service guys from Bollnäs are always available when needed,” Denis says in the end.
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