Fiber content is low with ash and impurities in barks. The barks have an adverse effect on the pulping process, and most of wood pulp mills need to get debarked first. Wood debarking can be done by different methods such as manual method, mechanical method and chemical method. Wood barker is the machine for debarking.
There are many types of mechanical debarking machines, which can be divided into: friction barker, blade barker and press barker according to their working principles. Friction barker is the most widely used type of debarking machine. It can be also divided into two types: wood-wood friction and wood-metal friction. Blade barker has high wood loss rate and low productivity, but it can do large-diameter wood debarking effectively. With the development of wood chipping industry, in the forest area, all the wood will be debarked and press barker will be applied in some enterprises.
Drum wood barker
Drum wood barker is a kind of friction debarking machine. It is debarked by wood collision in the drum. Drum wood barker is main equipment widely used in debarking wood in various countries.
The transmission mechanism of drum wood barker is that drum rotates around horizontal axis through gear drive, and the wood segment in the drum rotates with the drum and is lifted to a certain height, and then falls down, so that the collisions between drum wall, cutter shaft, debarking tools and wood segments are repeated, and the barks on the surfaces of the wood segments are subjected to impacting, pressing, shearing and debarked.
Drum wood barker can be divided into batch type and continuous type. The continuous type of drum wood barker can be divided into long wood debarking machine and short wood debarking machine. The former is also known as the parallel type drum wood barker, and the latter is also known as the tumbling type drum wood barker.
The drum diameter of the continuous short wood barker should be larger than wood length. Wood is randomly tumbled in the drum from one end to the other, and debarked gradually in mutual collision and friction. The debarking effect is better, the debarking degree is high, the loss rate is small, the equipment structure is simple, the management and maintenance are convenient, and the required operators are fewer. The disadvantage is that the machine is bulky and noisy, and the floor space is larger. The two ends of the wood may cause damages due to collisions, and it is easy to carry with debris such as sand and affect the quality of the pulp. The wood used in the continuous long wood debarking machine is larger in diameter and longer in length (close to or beyond drum diameter). Under the same drum volume and rotation speed, the long wood debarking machine has a 30% higher production capacity, and the damage at both ends is less, and the loss is reduced.
The continuous drum wood barker can be divided into dry and moist methods according to the operating conditions. In the moist drum wood barker, water is added to the steel plate in front of the drum (feeding end) to assist in loosening the barks, and the other parts of the drum is slotted to allow the barks to fall down during the continuous move of wood segments. In the dry drum barker, the entire length of the drum is opened with slots for discharging the barks. The length is longer than that of the wet drum wood barker, and the rotation speed is higher; the advantage of the dry drum wood barker is that the removed barks can be directly sent to the bark boiler for combustion. But it is only suitable for newly cut wood. The barks from the wet drum wood barker must be collected in a water tank for dewatering and compression prior to combustion, which makes the treatment of waste water get difficult and costly ultimately.
Currently, China pulp mills use continuous wet short wood barker. The continuous barker consists of drum, tumbling ring and support, transmission device, water tank, and an inlet and outlet shutter. The wood is continuously fed from the feeding end of the drum, and the barks are continuously overflowed from the other end of the drum. The production capacity of the debarking machine and the cleanliness can be adjusted by changing the amount of feeding amount and the height of the outlet shutter.
Blade wood barker
Blade wood barker is a kind of debarking machine that uses blade rolls or cutter disc to remove the barks. The characteristics of blade wood barker are: simple structure and convenient maintenance. The operation is easy, but the labor productivity is relatively low, and the debarking loss rate is relatively high, and the labor intensity is large. Blade wood barker consists of tumbling mechanism, blade roll and others.
As a leading paper making equipment manufacturer, AGICO can provide you with high quality wood debarking machine and relevant information about wood barker in details.