Debarker

The Rotary Debarker is an innovative development in debarking technology employing a combination of mechanical abrasion and log-to-log contact to efficiently remove bark from logs of all shapes and species. The result is cleanly debarked logs with minimal fibre loss, from difficult to debark and widely varying furnish. 

Features of the Rotary Debarker include:

• Full contact of rotors along entire length of log ensuring small diameter, crooked and swept logs can be effectively debarked.
• Far gentler action than conventional drum debarkers ensuring fewer damaged logs, less fibre loss and lower operating costs.
• Bark is expelled to a separate conveyor.
• The modular design ensures the system can be sized to fit any application.
• The Debarker design uses inclined abrasive plates, necessary when dealing with tough species and frozen conditions.
• The Rotary Debarker has been proven in over 250 installations worldwide. This includes 50+ systems in North America, many of which are in Pulp and OSB woodrooms operating 24 hours per day.

Process Description/Features

Delivery

Logs can be fed either longitudinally from the end or transversely from the side with the wood axis parallel to the debarker axis.

Rotor Contact

Bond between bark and wood broken at the cambium layer by:

• Contact with debarking plates
• Log-to-log contact

As the rotors turn – they bring the debarking plates into contact with the bark. This contact, along with the log to log contact within the debarking chamber breaks the bond between the wood and the bark at the cambium layer.

Inclined Plate

With other rotary debarker designs, the plate is installed without an incline. In the Rotary Debarker design, the plate is oriented at an angle to the rotor surface rather than level with the surface. This design optimizes the angle of force imparted onto the log and promotes:

• Optimal individual log rotation exposing more of the bark surface to the debarking plates
• Optimal over-all log rotation within the chamber exposing more logs to the debarking plates
   

Bark Expulsion

Loosened bark drops to the waste conveyor beneath the debarker.

Rotor Comb

The Rotary Debarker design incorporates fixed rotor combs between and to the sides of the rotors. These fixed combs contain slots through which the inclined debarking plates pass as the rotors turn. The action of the plates passing through these slots provides a slicing/shearing action that cuts loosened bark and drives it into the area below the rotors where it is deposited in the waste conveyor. This allows a very effective separation of the fibre and bark streams and eliminates the opportunity for bark remaining and being discharged at the debarker outfeed along with the debarked fibre. 

Plate Profile Aggressiveness

The debarking plate profile can be varied to suit variations in:

• Wood species
• Seasonal variation ( e.g. frozen conditions)
• Wood size and shape
• Freshness

The Rotary Debarker design offers six different plate profiles that are bolt-on detachable and re-buildable.

Gate Height

The final control variable is the discharge gate. The gate height is controlled by the operator and has the effect of controlling the wood fill level within the debarker. Raising and lowering the gate raises and lowers the fill level of logs within the debarker.

Advantages of the Rotary Debarker

• Allows simultaneous processing of a wide variation in species, diameter, length and shapes.
• Proven in over 250 installations worldwide; many North American operations running 24/7.
• Modular design can accommodate plant level capacities in Pulp and OSB applications as well as the single module requirements of woodyard residual clean-up.
   

"The Debarker is manufactured in North America by Carmanah Design and Manufacturing Inc. under license from Fuji Kogyo Co. Ltd. of Japan."