Roller Debarkers

The BE&E  roller debarker was initially developed for use in South American Acacia, whose bark is very tough and stringy. Traditional drum debarkers struggled to get the bark off and then to separate the bark from the logs as they exited the drum. In a drum. the Acacia bark would turn into a ball and not fall out of the stream of logs, ending up in the chipper. The drum debarker also was too aggressive for the small wood, often breaking those so that they ended up in the bark instead of the chipper.

The design goal was to achieve less than 2% bark content and less than 1% wood loss with stems down to 3”.

Our solution of tearing the bark off and through a comb plate is very effective. The result is a bark percentage of less than 0.8%, and wood loss below 0.5% even though the tests contained many stems below 3”.

The unit is built in 40’ modules with the ability to link up to 3 modules.

3 modules, operating in unfrozen softwoods can achieve a production rate of up to 150 TPH.

The rollers, comb plates and abrader mounts are made from wear resistance steel for long life. The abraders are hardened, heat treated and bolt in place. There are several types of abraders available to allow adjustment of debarking. This is especially important for adjusting to frozen, winter wood.

Roller Debarker Features

• Effective debarking with minimal fiber loss
• Great for crooked, short and small woods
• Requires less energy than a drum debarker
• Can be used for debarking and contaminant removal from stumps, log trims and cut-offs
• Variable speed independently driven rollers allow for fine tuning of debarking process
• Can handle logs with diameters as small as 3 inches, or as large as 32 inches
• Quieter than a drum debarker
• Lower installation cost than a drum debarker
• Can be easily reconfigured for softwood or hardwood
• Modular construction with one to three module configurations
• Capacity of up to 150 tons/hour with 3 modules in line
• Can handle logs as short as 40 inches, or as long as 20 feet

Specifications:

• Log diameters ————–up to 20” standard, larger by request
• Log lengths —————–up to 17’ standard, custom length by request
• Production —————–up to 50 TPH per module

The debarking principle and features

The basic unit features a single 40’ long module with three rollers on variable speed drives. Wood is tumbled as the rollers rotate under the wood with teeth (called abraders) and try to carry the wood up a progressive slope. Eventually, as the wood rises up the slope, the angle becomes too high, the grip of the rollers is lost to gravity and the wood tumbles back to the bottom.

This tumbling action causes the wood to impact with each other to loosen the bark. The abraders grab the loose bark, pull it from the log and through comb plates piece by piece. The flow of bark to the waste conveyor below is steady and consistent. Very little bark leaves the debarker with the logs. That bark that does leave is loose, in small pieces and easily removed in rollers.

The process

The process begins with a logs being fed into the unit by log deck, step feeder or other form of steady and controllable feed.  The rollers are adjusted to the correct speed to carry the wood to a target height on the slope wall. The speed of each roller is independently adjustable to optimize the flow rate and debarking .

An exit gate allows is used at the start of the process to fill the debarker to achieve the right balance of flow and throughput. This gate can be adjusted at any time with hydraulics.

The wood exits the end of the system and crosses over spaced rollers that act to do the final bark separation.  In this section is where log separation can also occur to control the feed to a chipper.