Wood waste disposal with technical ingenuities

Ever since the technical details became known, everyone has been talking about the new sawmill in Meßkirch/DE and the connected further processing plant. Together, Ferdinand Schneider, Managing Director of best wood Schneider, and Andreas Schilling, project manager for technical plants and factory manager in Meßkirch, planned a production site that takes the word “online sawmill” to a new level.

From the log infeed, the saw lines and the continuous kiln to the finished cross-laminated timber element, everything is done without the need for a forklift truck. CLT production is scheduled to start in the second quarter of 2023. The sawmill is designed for an annual cutting capacity of 350,000 m³ of log wood, which is done with two EWD log bandsaws and a Hewsaw chipper canter line. The “online” log infeed was supplied by Holtec, while Kallfass delivered the lumber sorting and mechanization and Valutec the continuous kiln. As mentioned at the beginning, Rudnick & Enners was responsible for the entire wood waste disposal system.

100% availability of wood waste

Construction in Meßkirch started in March 2021. “Exactly one year later, the first log passed through the machines,” Schilling tells us. Since then, the sawmill has never stood still and is currently running at 70% of the planned capacity. According to best wood Schneider, the Rudnick & Enners disposal system has 100% availability. “Rudnick & Enners was our first choice and convinced us with the layout and concept of the disposal system as well as with cost-effectiveness,” the factory manager explains and adds: “The collaboration was very fruitful. Working with Rudnick & Enners was and is always pleasant and professional.”

“The wood waste disposal has a number of special features,” Rudnick & Enners’s Managing Director Sven Rudnick explains during the tour of Meßkirch. The entire disposal level is located on the ground floor, while the cutting lines and parts of the disposal system are elevated so that the disposal level can be accessed with a skid loader. All units are easily accessible, among other things to simplify maintenance.

Star screen and bark mill for homogenous wood fuel

At the entrance of the saw line, the logs are debarked with two Valon Kone machines. Rudnick & Enners then feeds the bark as well as chips and cuttings from the boards, which accumulate during sorting, into the RMV 1600 bark mill. The mill is equipped with a 160-kW motor and has a grinding tunnel diameter of 1,600 mm. It is insensitive to foreign matter and has no screen basket. In combination with the downstream star screen, the bark mill produces wood fuel with a grain size of 0 to 100 mm. Defining a certain grain size was necessary because of the stoker screws which feed the material into the boiler. In order to meet this requirement, Rudnick & Enners built a star screen which sorts the wood waste with high precision. “We also use this technology to process bark for landscape gardening, where the biomass is reduced to various particle sizes, such as 0 to 10 mm or 0 to 40 mm,” Rudnick explains. The wood waste is transported to the warehouse on a tubular belt conveyor. The ground bark is then conveyed on a pivoting belt to the automated bark box, which includes an interface to the removal device.

Energy-efficient transport

The sawdust and chips from the edge bander are transported to the Rudnick & Enners TH 300/1050/5 drum chipper, which has 90 kW drive power, using vibrating feeders. As for the latter, the plant manufacturer relies on special resonance conveyors: “Thanks to the close-to-resonance adjusting of the vibrating feeders, energy-efficiency is also guaranteed over longer conveying distances,” Rudnick tells us.

The wood waste from the two log bandsaws and the chipper canter line as well as the material from the drum chipper are transported to the RS 3x15 rotating screen on belt conveyors. The rotating screen separates the wood chips from the sawdust, and oversized grains are fed into the bark mill. Tubular belt conveyors transport the sawdust into the silo and the wood chips into a covered storage area. “At the moment, we bring the wood chips to Eberhardzell, where we process them in our insulation panel plant. In the future, however, we’d like to process the wood chips in Meßkirch, too,” Schilling explains.

“We are very happy with the collaboration with Rudnick & Enners. It was the right decision,” Schilling says. “We were especially pleased with the quick solutions and the short decision-making processes.”