SU1556908A1 - Method of separating bark - Google Patents

Abstract

The invention relates to the forest industry, in particular to methods for the separation of bark. The goal is to reduce energy consumption. The bark after debarking is crushed by impact with an energy exceeding the energy to overcome the adhesion forces of the crust and bast, but less energy required to destroy the bast. The crushed mass is sorted according to the screening surface, and the bast particles are oriented relative to their longitudinal axis at an angle of 60-90 ° to the direction of movement. The openings of the sorting surface in the direction of orientation are made with dimensions smaller than in the perpendicular direction. In the process of separating bast and peel, cyclical reciprocating movement of the material to be divided is carried out in the plane of the screening surface. 1 hp ff, 1 ill.

Description

The invention relates to the forest industry and can be used in the separation of wood bark into bast and crust.

The purpose of the invention is to reduce the energy intensity of the separation process.

The method of bark separation is carried out as follows.

The bark obtained by debarking the wood after preliminary removal of large flakes of wood from it is selectively crushed by impact impact with energy exceeding the energy to overcome the forces of the crust and bast, but less energy needed to chop the bast. The product obtained after this treatment is a crust crushed to small scales (medium diameter up to 15 mm, thickness up to 3 mm) and bast in the form of elongated strips with an average length of 100-150 mm. At the same time, the crust is almost entirely separated from the bast.

Next, the resulting product is sorted by screening surface.

with holes. Sorting is carried out, for example, in a drum sorting, the openings of the sorting surface of which are made with dimensions of 5-8 mm in the direction of bast particles orientation with the help of spiral turns (or coaxially assembled rings). In the process of separation of the crust and bast, cyclical reciprocating movement of the material to be divided is carried out in the plane of the screening surface. In this case, the flakes of the crust, when moved along the screening surface, pass into the apertures, collect into the receiver and are sent for further use.

When the particles of the bast are oriented at an angle of 60-90 ° relative to their longitudinal axis to the direction of movement along the screening surface, even thin bands of the bast do not pass into the holes. Passing the screening surface, the bast is collected in the receiver and sent for further use.

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Other embodiments of the sorting surface are possible, for example, in the form of a perforated plane that communicates oscillatory movements. The energy intensity of the proposed bark separation method can be reduced if, prior to the impact, to perform a preliminary sorting of the bark with release of unborn peel, and to expose the rest of the material to the impact.

The drawing shows schematically the devices that implement the proposed method.

The devices comprise a hammer mill 1 connected to a drum mill and oriented in the longitudinal direction, i.e. at an angle close to 90 ° to the direction of travel during the collapse. With such an orientation, even thin bands of bast, as a result of their elongated shape, do not pass between the turns of the spiral with a 6.5 mm gap. Due to the slight inclination (about 2 °) of the screening surface, the bast particles are transported along the longitudinal axis and collected in a bore receiver for the bast. The crust, when moving along the surface of the sieve during the collapse, falls into the gap between the turns of the helix and enters the receiver. The impurity of bast in the crust is 2.5%; admixture of peel in bast 2.3%,

2, the screening surface of which is the energy intensity of the separation process of the bark of the cortex is made in the form of a helical spiral

3, inside of which are installed the orienting elements in the form of longitudinal beams 4. Example. The bark, obtained after debarking, is subjected to shock impact with an energy of 4 in a mill with a diameter of 800 mm with four rows of beats with a vertical rotor having a rotation speed of 700 rpm. Processing time 3-5 seconds. productivity 2 t / h The resulting product is a mixture of bast and peel, energy intensity practices, the bark is reported to be completely energetically separated from each other by shock, exceeding

the energy of the adhesion forces of the crust to the bast, but less than the grinding energy of the bast, and when sifting the particles of the bast are oriented relative to their longitudinal axis at an angle

20

is 4.08.

Claims (2)

Invention Formula . A method of dividing wood bark into bast and crust by impacting the bark and then sorting the separated materials when moving along a screening surface with holes, characterized in that, in order to be cut. Bast is obtained in the form of strips 100-150 mm long, and the crust in the form of flakes with an average diameter of 15 mm and a thickness of 3 mm. For the final separation, the mixture is screened in a drum sort - 30-60-90 ° to the direction of movement, and 1000 mm in diameter and 2 m in length. The crust performs cyclic movements consisting of lifting together with the screening surface and breaking it along it while the drum rotates at a speed of 15 rpm. Inside the sorting there are longitudinal beams installed at a distance of 150 mm from one another around the circumference of the drum. The elongated bands of bast when sliding on the sorting surface, interact with the longitudinal The openings of the sorting surface in the direction of orientation are made with dimensions smaller than in the perpendicular direction. 35 2. The method according to claim 1, characterized in that during the separation of the bast and the peel, cyclical reciprocating movement of the material to be divided is carried out in the plane of the screening surface. the energy intensity of the bark separation process energy intensity, the crust imparts an impact energy exceeding is 4.08. Invention Formula . The method of dividing the bark of wood into bast and crust by impacting the bark and then sorting the separated materials when moving along the screening surface with holes, characterized in that, in order to move 60-90 ° to the direction of movement, The openings of the sorting surface in the direction of orientation are made with dimensions smaller than in the perpendicular direction. 2. A method according to claim 1, characterized in that during the separation of bast and peel, cyclical reciprocating movement of the material to be divided is carried out in the plane of the screening surface. # 0ra  7 Separated qp # a / 3 H / w wv w w wwv Lorna