Project description

A chain conveyor is used for proper feeding of the wood into the chipper. It is considerably cheaper when compared to roller conveyor. It also requires less maintenance and is safer to operate. The conveyor has seven chains of which the four feed chains are driven by a hydraulic engine of type CA 50 Hägglunds Compact 30kW. The three side chains are driven by a hydraulic motor of type CA 50 Hägglunds Compact 22kW. A height limiter is mounted to avoid jams caused by logs that are too large being fed into the chipper. In case of a jam, the three side chains will first be driven on reverse to loosen the logs and at the same time, the log lifter located on the side of the chain conveyor will be activated.

A high performance horizontally fed mill with a cutting aperture of 800 mm.

Main components of the machine:

  • Cutting board with axle and storage
  • Forward and back frames
  • Cover for the cutting board

Behind the cutter is a large chip pocket, which equalizes the flow to a metering screw carrying chips on through a number of screw conveyors to the digester house.

Citec's scope

Citec’s scope consisted of design engineering of a new wood room line. Citec created a layout based on the customer’s requirements for capacity and physical locations and complete calculations for the chain conveyor, cutter and chip pocket together with the manufacturing drawings. Citec also calculated and created the following chip pocket as well as designed the metering screw and the included screw conveyor.

Case in brief
Customer: Södra Cell AB, Sweden
Project location: Sweden
Technical data:
  • Diameter of cutting board: 3400 mm
  • Thickness of cutting board: 210 mm
  • Speed of cutting board: 246 rpm
  • Number of knives: 12 pc.
  • Max. diameter of log: 800 mm
  • Chip length: 16-35 mm
  • Capacity based on chip length: 800-1300 m3 chip/hour
  • Inertia moment J: 23 600 kgm2
  • Heaviest weight on the lift rotor (axle, cutting board and storage): 18 00 kg
  • Net weight excluding motor and gear system: 31 000kg