EP3225370A1

EP3225370A1 - Method and system for production of oriented structural shaving board

Info

Publication number: EP3225370A1
Application number: EP15852333.2A
Authority: EP
Inventors: Shouhua Liu
Original assignee: Dieffenbacher Machinery Services (beijing) Co ltd
Current assignee: Dieffenbacher Machinery Services (beijing) Co ltd
Priority date: 2014-10-24
Filing date: 2015-10-23
Publication date: 2017-10-04
Also published as: CN104325535B; CN104325535A; WO2016061908A1

Abstract

Provided are a method and system for production of an oriented structural shaving board, comprising the following steps: S10. Performing a length slicing on fragmental veneer strips produced when producing plywoods using a veneer longitudinal shearing machine (10); S15. Performing a width slicing on the fragmental veneer strips using a veneer transversal shearing machine (11); S20. Obtaining shavings of qualified dimensions through a primary screening; S30. Drying the shavings by a drier; S35. Sorting surface-layer shavings and core-layer shavings through a secondary screening; S40. Respectively glueing the surface-layer shavings and core-layer shavings; S45. Performing a directional spreading on the glued shavings by a directional spreading machine; S50. Hot-pressing the well-spread slabs using a hot press; and S55. Cutting the hot-pressed oriented structural shaving board into specified dimensions.

Description

Technical field

The invention is related to the wood-based panel producing field.
It is especially related to an producing method and producing system of an oriented strand board (OSB).

Technical background

Oriented Strand Board is a kind of high strength man-made board which has been developed in Europe and America in the late 70's and early 80's. A process for producing oriented strand board needs large diameter wood and small diameter branches as raw material, uses special strand making equipment (e.g. long log strander or two stage strand producing equipment) which processes the material along the wood grain direction into flakes with 80 mm - 130 mm length, 5 to 30 mm width and 0.3 to 0.8 mm thickness. After drying, gluing and oriented forming, the oriented aligned flakes are interlaced to longitudinal and cross layers. Then the mat is pressed to an artificial board. Its mechanical properties are significantly higher than ordinary particleboards, which are equivalent to that of plywood.
The wood working industry in China is developing fast. But the proportions of different kinds of boards are not reasonable. Compared with the developed countries, the proportion of plywood in China is high, while particleboards, especially OSB have a smaller ratio. The production of blockboard and plywood belong to resource consuming and labor-intensive industries with an extensive producing mode. Each year large volumes of wood resources are consumed but have very low industrial added values.
OSB has advantages in its mechanical properties. It can realize large scale production through automation with diversifying product dimensions. It can satisfy different size and thickness requirements. The OSB has low formaldehyde release or ist even formaldehyde free and therefor an environmental friendly product. It can be used in practical application as a kind of upgrade product by replacing traditional kinds of boards.
After years of market cultivation the domestic OSB import volume has increased and the market have been matured. The Shunxin board line jointly constructed and jointly developed by Dehua company, listed in China and Ainsworth company, listed in Canada, had formally put into production at the end of 2013. The jointly developed Shunxin board, in the application aspects of environmental protection, stability, screw holding ability, flatness and decoration, realized a completed innovation and surpasses traditional ecological boards in comparison, like blockboard, plywood, etc.
The Shunxin board of Dehua is mainly used in structural areas. Especially 90% is used in a wooden house or a steel-wood structure. It is suitable for large modem building construction, decoration field, and is widely used in building private houses and villas. Recently the Power Deko company promoted OSB as computer room partition. And some companies use OSB in indoor and outdoor decoration and other fields. Also recently some factories develop its application in industrial sewing machine table. It is believed that the applications of the OSB product will provide huge business opportunities for Chinese industry enterprises.
The first large scale OSB production line in Asia was put into use in Jingmen Hubei in 2010. It fills the cavity of domestic OSB production. This company adopts "company + base + farmers" business models and implemented a fast-growing forestry base. All materials are using large diameter fast-growing poplars. The company uses a continuous working horizontal hot pressing machine, which represents the current internationally most advanced technology.
But the timber resources have a shortage in China, especially good large diameter materials, which rely on imports. The nation does not promote enterprises to use this production mode of mass consuming large diameter logs. So enterprises may feel greatly restricted in the production and development by the headache of raw material supply. So, in china, if we want to promote using OSB, its production process must be improved by solving the problems of source and acquisition of raw material.
As of the fast growing small diameter wood, it is essential for the daily production for plywood. During production, plywood enterprises produce a large volume of crashed veneer strips during wood peeling. This is because logs are not compete round and straight, and have a sharpened taper. This factors and not precise centering lead to the production of a large amount of low grade fish tail shaped veneers, veneers with big knots or knot holes or severe cracking. Generally only about 30% of the cracked veneers, after a lot of human splicing, can be used as care layer of plywood. If these are used improperly, it affects the strength of the plywood products, and cause the loss of a product grade. At present the plywood production capacity in China is the first in the world. In 2013 the national plywood cumulative production capacity is of 157.4 million m³. In China mainly fast growing eucalyptus or poplar (considering 8 years growing period) is used as raw material, the comprehensive utilization ratio of wood is about 50% - 70%. In a calculation according to 70% of the lumber utilization rate, the residual cracked veneer strips emerged from the plywood enterprises every year reach 47.22 million m³. But the large volume cracked veneer strips as such are not well used, only parts are used by cutting them into small wood shavings for producing partideboard, most of them are taken as burnable fuel. This is a waste of resources. Furthermore the current domestic plywood market undergoes intense competition. Not only private small companies try hard to survive, part of the large scale companies have also difficulties. It there is improvement for the comprehensive utilization rate of timber, it will greatly improve enterprise's survival and profitability. And furthermore it is possible to fill in the lacking of structural boards, which are imported in a large volume.

Content of the invention

The purpose of the invention is to provide a method for producing Oriented Strand Boards. This method should utilize crashed veneer strips to produce a high strength OSB, therefore the comprehensive utilization ratio of wood is improved.
The invention uses the following technical scheme to solve the before mentioned technical problems for a method method for producing Oriented Strand Boards by the fallowing steps:

S10 - Cutting crushed veneer strips produced during plywood production in longitudinal direction to 50-180 mm strips with a longitudinal veneer shearing machine;
S15 - Cutting veneer strips in transverse direction with a transverse veneer shearing machine (20) to flakes with a final width of 5 - 40 mm;
S20 - Screening the with a disc screen while taking out the oversize flakes with length longer than 180 mm or width wider than 40 mm;
transporting the remaining flakes to a vibrating conveyor with a mesh for rejecting the fines with length shorter than 50 mm and width smaller than 5 mm and taking out the impurities and tiny particles by airgrading;
After cleaning, the qualified flakes are conveyed by a cyclone to a wet flake silo;
S30 Drying the flakes coming from the wet flake silo with a dryer to the moisture content of the flakes after drying of 3.0% - 5.0 %;
S35 Screening the flakes after drying in a screen to into surface layer flakes and core layer flakes;
S40 Gluing the surface layer flakes and core layer flakes;
S45 Oriented forming of the surface layer flakes and core layer flakes by using oriented forming machines;
S50 Hot pressing of the oriented mat to OSB;
S55 Cutting the OSB after the hot press to size.

Optionally in the described step S50, the hot press here used is a double steel belt continuous horizontal hot press or a multi-opening hot press.
Optionally, in the described step S35, surface layer flakes and core layer flakes after screening and separating are conveyed to air graders for rejecting impurities.
The invention uses the following technical scheme to solve the before mentioned technical problems for a system for producing Oriented Strand Boards by the following characteristics:

a longitudinal veneer shearing machine 10,
transverse veneer shearing machine 11,
a first wet flake silo 12, a disc screen 13, a vibrating conveyor 14, an air grader 15, a cyclone 16, a second wet flake silo 17, a dryer, a screen, a second glue blender, oriented forming machines and a hot press; wherein
the discharge outlet of the described longitudinal veneer shearing machine 10 is connected to the feed inlet of the second belt conveyor 23;
the discharge outlet of the second belt conveyor 23 is connected to the described transverse veneer shearing machine 11;
the discharge outlet of the transverse veneer shearing machine 11 is connected to the feed inlet of the first wet flake silo 12 via the third belt conveyor 18;
the discharge outlet of the first wet flake silo 12 is connected to the feed inlet of the disc screen 13 via the fourth belt conveyor 19;
the discharge outlet of the described disc screen 13 is connected to the feed inlet of the vibrating conveyor 14 via the No. 5 belt conveyor 20;
the discharge outlet of the described vibrating conveyor 14 is connected to the feed inlet of the air grader 15;
the discharge outlet of the air grader 15 is connected to the feed inlet of the cyclone 16; the discharge outlet of the described cyclone 16 is connected to the feed inlet of the second wet flake silo 17;
the discharge outlet of the described second wet flake silo 17 is connected to the feed inlet of the dryer via a belt conveyor or a scraper conveyer;
the discharge outlet of the described dryer is connected to the feed inlet of the screen; the discharging outlets for the surface layer flakes and core layer flakes from the screen are connected to a surface layer flake silo and a core layer flake silo;
the discharge outlet of the described surface layer flake silo is connected to the feed inlet of the first glue blender;
the discharge outlet of the described core layer flake silo is connected to the feed inlet of the second glue blender,
the discharge outlets of the described first glue blender and second glue blender are connected to the feed inlets of the oriented forming machines respectively;
the discharge outlets of the described oriented forming machines are connected to the feed inlet of the hot press.

Optionally the hot press here described is a double steel belt continuous horizontal hot press or a multi-opening hot press.
Optionally the described disc screen 13 consists of support 30, the first chute 31, the secpmd chute, multiple parallel transport rollers 33 and driving devices, wherein the described first chute 31 and the second chute are both installed and fixed on the support 30;
the first chute 31 is at the back side of the second chute;
left and right ends of each transport rollers 33 are installed on the support 30;
each transport roller 33 has multiple sorting discs 34 parallel with each other;
the axis of the sorting discs and the centre axis of the transport rollers 33 are coincident;
the two adjacent sorting discs 34 has a gap and the gap values are equal to each other;
the sorting discs 34 on the later transport roller 33 have a staggered arrangement comparing with the sorting discs 34 on the former transport roller 33;
the former sorting discs insert into the gaps between the later sorting discs;
the gaps of the staggered sorting discs equal to the max. width of the required flakes; the gaps of the two adjacent transport rollers equal to the max. length of the required flakes;
the most front side described transport roller 33 is located at the above and front side of the No. 1 chute 31;
the most back side described transport roller 33 is located at the above and front side of the No. 2 chute 31;
the flakes falling between the 2 adjacent transport rollers 33 fall into the first chute 31; the described driving devices are driving the described transport rollers 33 turning in clockwise or counter-clockwise rotation.
Optionally the described driving devices comprises a drive motor, a drive sprocket, a driven sprocket and a chain, wherein the described drive sprocket is installed in a transport roller 33, wherein each of the other transport rollers 33 have a driven sprocket installed, wherein the described drive sprocket is connected to the driven sprockets via a chain, wherein at one end of the transport roller where the drive sprocket is installed, it is connected to a drive motor.
Optionally the described chain has a tensioning sprocket 35 and that the described tensioning sprocket 35 is installed on the support 30.
Optionally the described first chute 31 and the second chute have a big top and a small bottom, like an inverted trapezoid shape.
Optionally the gaps between the center lines of the described transport roller 33 can be finely adjusted.
The invention provides the following benefits by using crashed veneer strips as raw material for the production of OSB:

(1) Saving of precious timber resources by improved wood comprehensive utilization. The residual cracked veneer strips emerged from the plywood enterprises every year reach 47.22 million m³. If in the plywood enterprises accumulative areas the residual cracked veneer strips are purchased nearby, and they are used for OSB production, then we can avoid the waste of resources.
(2) Less energy consumption: Using crushed veneer strips for OSB production needs only a simple cutting process for the fragile veneers therefore the energy consumption is low. Furthermore the crushed veneer strips have a low moisture content, the need less energy consumption during the drying process. If logs are used as raw material, the raw material has to be cooked, peeled, cutted, dried. There are many processing operations which consume a lot of energy.
(3) Increase of income by protecting the ecology: Large plywood enterprises can, through building a new factory use crushed veneer strips effectively, which will greatly improve enterprise's survival and profitability. Small plywood enterprises can sell crushed veneers, increase their income and help protecting the environment.

Description of the drawings attached

Figure 1: is a structural schematic drawing of a longitudinal veneer shearing of the system for producing Oriented Strand Boards.
Figure 2: is a structural schematic drawing of the veneer longitudinal shearing machine and the transverse veneer shearing machine of the system for producing Oriented Strand Boards.
Figure 3: is a structural schematic drawing of the transverse veneer shearing machine and the first wet flake silo of the system for producing Oriented Strand Boards.
Figure 4: is a structural schematic drawing of the disc screen and the vibrating conveyor of the system for producing Oriented Strand Boards.
Figure 5: is a structural schematic drawing of the air grader, cyclone and the second wet flake silo of the system for producing Oriented Strand Boards.
Figure 6: is a front view of the disc screen of the system for producing Oriented Strand Boards.
Figure 7: is a left view of the disc screen of the system for producing Oriented Strand Boards.

Reference list:

In the figures, the marks are for:

10: longitudinal veneer shearing machine
11: veneer transverse shearing machine
12: wet flake silo (first)
13: disc screen
14: vibrating conveyor
15: air grader
16: cyclone
17: wet flake silo (second)
18: belt conveyor (third)
19: belt conveyor (fourth)
20: belt conveyor (fifth)
21: belt conveyor (first)
22: forklift truck
23: belt conveyor (second)
30: support
31: chute (first)
33: transport rollers
34: sorting discs
35: tensioning sprocket

Concrete implementing way

In the following the technical scheme of the invention by combining with an implementing example and the drawings attached are elaborated.

Implementing example 1

The invention provides an producing method for OSB including the following steps:

S10: Cutting crashed veneer strips in longitudinal direction.
The crashed veneer strips which were produced during plywood production are transported to a longitudinal veneer shearing machine and are cut in longitudinal direction to 50 - 180 mm strips.
S15: Cutting strips in transverse direction.
The strips after the longitudinal cutting are transported to a transverse veneer shearing machine and are cut in transverse direction to flakes with a final width of 5 - 40 mm.
S20: First screening.
The flakes after cross cutting (S15) are transported to a disc screen. The oversize flakes with length longer than 180 mm or width wider than 40 mm are separated out and discharged. The remaining flakes are transported to a vibrating conveyor. At the conveying surface of the vibrating conveyor is a mesh. When the material flow passes through the vibrating conveyor, the fines with length shorter than 50 mm and width smaller than 5 mm are rejected by the mesh. The qualified flakes are conveyed to an air grader. The described air grader rejects the impurities and tiny particles in the material. After cleaning, the qualified flakes are conveyed by a cyclone to a wet flake silo.
S30: Drying.
The flakes coming from the wet flake silo are fed to a dryer for drying. The moisture content of the flakes after drying is 3.0% - 5.0%.
S35: Second screening.
The flakes after drying are transferred to a second screen. At here they are sifted into surface layer flakes and core layer flakes.
S40: Gluing.
Surface layer flakes and core layer flakes are glued respectively.
S45: Oriented forming.
Aligned forming of surface layer flakes and core layer flakes respectively to a flake mat by using forming machines.
S50: Hot pressing.
Using a hot press to press the flake mat.
A double steel belt continuous horizontal hot press is used. Hot pressing temperature is: 170 - 240 °C, pressure is: 1.5 - 6.5 N/mm², pressing time is: 6.0 - 11 seconds per mm thickness (to set optimal values according to board quality, using type of glue, board thickness). Based on the actual producing conditions, a multi-opening hot press can be used, too.
S55: Raw board handling.
The OSB is cut to size after the hot press.

It is preferred, that in the step S35 the surface layer flakes and core layer flakes after screening and separating are conveyed to air graders respectively to segregate impurities.

Implementing example 2

The invention also provides a method for producing OSB:
As shown in Figure 1, the feed inlet of the longitudinal veneer shearing machine 10 is connected with the first belt conveyor 21. The crushed veneer strips are loaded by a forklift truck onto the first belt conveyor 21 and they are fed into the longitudinal veneer shearing machine 10. Through harmonization of the infeed speed of the crushed veneer strips, the turning speed of rotor in the longitudinal veneer shearing machine 10 and the numbers or rotor knives, the infeed materials are cut in longitudinal direction to a length of 50 - 180 mm strips.
As shown in Figure 2, the discharge outlet of the longitudinal veneer shearing machine 10 is connected to the feed inlet of the second belt conveyor 23. The discharge outlet of the second belt conveyor 23 is connected to the transverse veneer shearing machine 11. The strips with longitudinal length of 50 - 180 mm are fed into the transverse veneer shearing machine 11. The strips already cut in longitudinal direction will be fed in transverse direction and are cut by the transverse veneer shearing machine 11 to flakes with a final width of 5 - 40 mm.
As shown in Figure 3, the discharge outlet of the transverse veneer shearing machine 11 is connected to the feed inlet of the first wet flake silo 12 via the third belt conveyor 18. The flakes are transported into the first wet flake silo 12 for intermediate storage.
As shown in Figure 4, the discharge outlet of the first wet flake silo 12 is connected to the feed inlet of the disc screen 13 via the fourth belt conveyor 19. The fourth belt conveyor 19 is located under the discharge outlet of the first wet flake silo 12. The oversize flakes with length longer than 180 mm or width wider than 40 mm are separated out and discharged by the disc screen 13.
As shown in Figure 6, the disc screen 13 consists of a support 30, a first chute 31, whereas the second chute it is not shown in the Figure. Multiple parallel transport rollers 33 are shown in this figure only as one transport roller with assembled the sorting discs on it and driving devices. The first chute 31 and the second chute are both installed and fixed on the support 30. The first chute 31 is at the back side of the second chute. Both left and right ends of each transport rollers 33 are installed on the support 30. On each transport roller 33 there are multiple sorting discs 34 parallel with each other. The axis of the sorting discs and the center axis of the transport rollers 33 are coincident. The two adjacent sorting discs 34 have a gap and the gap values are equal to each other. The sorting discs 34 on the later transport roller 33 have a staggered arrangement comparing with the sorting discs 34 on the former transport roller 33. The former sorting discs insert into the gaps between the later sorting discs. The gap between the former sorting disc 34 and the later transport roller 33 will be accepted when it is not influence the rotation. For example, the gap might be 1 mm. The gaps of the staggered sorting discs equal the max. width of the required flakes. In the implementing example, it is 40 mm. The gaps of the two adjacent transport rollers equal to the max. length of the required flakes, In the implementing example, it is 180 mm. The most front side described transport roller 33 is located at the above and front side of the first chute 31. The most back side described transport roller 33 is located at the above and front side of the second chute 31. The flakes falling between the 2 adjacent transport rollers 33 fall into the first chute 31. The described driving devices are driving the described transport rollers 33 turning in clockwise or counter-clockwise rotation.
As shown in Figure 7 of the implementing example, the driving devices comprise drive motor, drive sprocket, driven sprocket and chain. The drive sprocket is installed in a transport roller 33. In each other transport roller 33 a driven sprocket is installed. The drive sprocket is connected to the driven sprockets via a chain. At one end of the transport roller where installs the drive sprocket, it is connected to a drive motor. The chain has a tensioning sprocket 35. The described tensioning sprocket 35 is installed on the support 30. Drive pulleys and gears can be used to connect the transport rollers, and then are driven by a motor.
In the implementing example, the first chute 31 and the second chute have a big top and a small bottom, like an inverted trapezoid shape. The first chute 31 is a chute for qualified flakes. The second chute is a chute for oversize flakes.
The gaps between the center lines of the transport roller 33 can be adjusted in a fine manner. By adjusting the gaps between the center lines of the transport roller, according to the required flake length the gaps between the adjacent two transport rollers is determined. The way of adjusting the positions of the transport rollers can be done by moving the positions of the bearing pedestals. The bearing pedestal are fixed onto the support through oblong holes.
When the disc screen works, the sorting discs are turning under the drive for the transport rollers. The oversize flakes with length longer than 180 mm or width wider than 40 mm are transported on the sorting discs from front to back and fall into the second chute. The flakes with length equal to or less than 180 mm and width equal to or less than 40 mm fall into the gaps between the sorting discs and into the first chute. In the implementing example, the shape of the sorting disc is round. The shape can also be oval, which will have better material dispersing effects.
The discharge outlet of the first chute 31 of the disc screen 13 is connected to the feed inlet of the vibrating conveyor 14 via the fifth belt conveyor 20. The remaining flakes are transported to a vibrating conveyor 14. In the vibrating conveyor, different sizes of flakes are transported, and the flakes are evenly distributed along the entire width. At the conveying surface of the vibrating conveyor is a mesh. The mesh hole size is determined by the size of the fines need to be rejected. When it is vibrating and transporting the material, at the same time it rejects the fines.
As shown in Figure 5 the discharge outlet of the vibrating conveyor 14 is connected to the feed inlet of the air grader 15. The discharge outlet of the air grader 15 is connected to the feed inlet of the cyclone 16. The discharge outlet of the described cyclone 16 is connected to the feed inlet of the second wet flake silo 17. The air grader is to reject impurities and fine particles. By the cyclone 16, the flakes are conveyed to the second wet flake silo 17. At the same time, the cyclone is effectively separating out fine wood particles. It is to avoid polluting air by de-dusting.
The discharge outlet of the described second wet flake silo 17 is connected to the feed inlet of the dryer via a belt conveyor or a scraper conveyer. The flakes are dried by the dryer. The moisture content of the flakes after drying is 3.0% - 5.0 %. The discharge outlet of the dryer is connected to the feed inlet of the screen. They are sifted into surface layer flakes and core layer flakes by the screen, which are then transported into a surface layer flake silo and a core layer flake silo respectively. The ratio of surface layer flake comparing with core layer flake will be determined by the grade of the OSB to be, the board thickness, glue types of surface layer and core layer, etc. The forming surface layer uses big flake, while the forming core layer uses small size flakes.
For example, if an OSB 3 grade board with a board thickness of 16 mm is to be produced, in the surface layer MUPF glue is used, while the core layer uses PMDI glue and the ratio of surface layer is 50%.
To produce an OSB 3 grade board with thickness of 25 mm, the surface layer uses MUPF glue, the core layer uses PMDI glue and the ratio of the surface layer is 45%. The discharge outlet of the surface layer flake silo is connected to the feed inlet of the first glue blender. The discharge outlet of the core layer flake silo is connected to the feed inlet of the second glue blender. The surface layer flakes and core layer flakes are glued respectively. The discharge outlets of the first glue blender and second glue blender are connected to the feed inlets of the oriented forming machines respectively.
The surface layers are at the top side and bottom side of the core layer. The texture directions of the surface layer and the core layer are perpendicular to each other. The discharge outlets of the described oriented forming machines are connected to the feed inlet of the hot press. The hot press is a double steel belt continuous horizontal hot press or a multi-opening hot press. The formed mat is pressed by the hot press and it becomes the oriented strand board. Then through saws the board after the press is cut along the length (edge cutting) and the width (diagonal cutting), therefore different dimensions of boards can be acquired.
This invention applies crushed veneer strips (all use or part use) and hot press (including multi-opening hot press or double steel belt continuous horizontal hot press). The Oriented Strand Board (OSB) in accordance with the Chinese national standard and/or European standard can be produced. This invention expands and enriches sources of raw materials for the OSB production. It reduces the bottleneck of having to use large diameter logs. It is completely suitable to China's national conditions.
The sequence of the above implementing examples is just for convenience of description. It does not represent the merits of the cases.
Finally it shall be pointed out, that the above implementing examples are only used for describing technical schemes of the invention, rather than giving limitations on it. Although in reference to the foregoing examples a detailed explanation of the invention is done, the common technical personnel in this field shall understand: the technical schemes written in the above mentions each of the implementing examples can still be revised, or partial technical characteristics can be equivalently substituted. However, these revises or replace, they don't make the essence of the corresponding technical solution out of the present spirit and scope of technology solutions in the implementing examples in the invention.

Claims

A method for producing Oriented Strand Boards comprising the following steps:
S10 - Cutting crushed veneer strips produced during plywood production in longitudinal direction to 50 - 180 mm strips with a longitudinal veneer shearing machine;

S15 - Cutting veneer strips in transverse direction with a transverse veneer shearing machine (20) to flakes with a final width of 5 - 40 mm;

S20 - Screening the with a disc screen while taking out the oversize flakes with length longer than 180 mm or width wider than 40 mm;

transporting the remaining flakes to a vibrating conveyor with a mesh for rejecting the fines with length shorter than 50 mm and width smaller than 5 mm and taking out the impurities and tiny particles by airgrading;

After cleaning, the qualified flakes are conveyed by a cyclone to a wet flake silo; S30 Drying the flakes coming from the wet flake silo with a dryer to the moisture content of the flakes after drying of 3.0% - 5.0 %;

S35 Screening the flakes after drying in a screen to into surface layer flakes and core layer flakes;

S40 Gluing the surface layer flakes and core layer flakes;

S45 Oriented forming of the surface layer flakes and core layer flakes by using oriented forming machines;

S50 Hot pressing of the oriented mat to OSB;

S55 Cutting the OSB after the hot press to size.
Method according to claim 1, characterized in that, in the described step S50, the hot press here used is a double steel belt continuous horizontal hot press or a multi-opening hot press.
Method according to claim 2, characterized in that, in the described step S35, surface layer flakes and core layer flakes after screening and separating are conveyed to air graders for rejecting impurities.
A producing system for Oriented Strand Boards, comprising:
a longitudinal veneer shearing machine (10),

transverse veneer shearing machine (11),

a first wet flake silo (12), a disc screen (13), a vibrating conveyor (14), an air grader (15), a cyclone (16), a second wet flake silo (17), a dryer, a screen, a second glue blender, oriented forming machines and a hot press; wherein

the discharge outlet of the described longitudinal veneer shearing machine (10) is connected to the feed inlet of the second belt conveyor (23);

the discharge outlet of the second belt conveyor (23) is connected to the described transverse veneer shearing machine (11);

the discharge outlet of the transverse veneer shearing machine (11) is connected to the feed inlet of the first wet flake silo (12) via the third belt conveyor (18);

the discharge outlet of the first wet flake silo (12) is connected to the feed inlet of the disc screen (13) via the fourth belt conveyor (19);

the discharge outlet of the described disc screen (13) is connected to the feed inlet of the vibrating conveyor (14) via the No. 5 belt conveyor (20);

the discharge outlet of the described vibrating conveyor (14) is connected to the feed inlet of the air grader (15);

the discharge outlet of the air grader (15) is connected to the feed inlet of the cyclone (16);

the discharge outlet of the described cyclone (16) is connected to the feed inlet of the second wet flake silo (17);

the discharge outlet of the described second wet flake silo (17) is connected to the feed inlet of the dryer via a belt conveyor or a scraper conveyer;

the discharge outlet of the described dryer is connected to the feed inlet of the screen;

the discharging outlets for the surface layer flakes and core layer flakes from the screen are connected to a surface layer flake silo and a core layer flake silo;

the discharge outlet of the described surface layer flake silo is connected to the feed inlet of the first glue blender;

the discharge outlet of the described core layer flake silo is connected to the feed inlet of the second glue blender;

the discharge outlets of the described first glue blender and second glue blender are connected to the feed inlets of the oriented forming machines respectively;

the discharge outlets of the described oriented forming machines are connected to the feed inlet of the hot press.
System according to claim 4, characterized in that, the hot press here described is a double steel belt continuous horizontal hot press or a multi-opening hot press.
System according to claim 4, characterized in that, the described disc screen (13) consists of support (30), the first chute (31), the secpmd chute, multiple parallel transport rollers (33) and driving devices, wherein
the described first chute (31) and the second chute are both installed and fixed on the support (30);
the first chute (31) is at the back side of the second chute;
left and right ends of each transport rollers (33) are installed on the support (30); each transport roller (33) has multiple sorting discs (34) parallel with each other; the axis of the sorting discs and the centre axis of the transport rollers (33) are coincident;
the two adjacent sorting discs (34) has a gap and the gap values are equal to each other;
the sorting discs (34) on the later transport roller (33) have a staggered arrangement comparing with the sorting discs (34) on the former transport roller (33);
the former sorting discs insert into the gaps between the later sorting discs;
the gaps of the staggered sorting discs equal to the max. width of the required flakes;
the gaps of the two adjacent transport rollers equal to the max. length of the required flakes;
the most front side described transport roller (33) is located at the above and front side of the No. 1 chute (31);
the most back side described transport roller (33) is located at the above and front side of the No. 2 chute (31);
the flakes falling between the 2 adjacent transport rollers (33) fall into the first chute (31);
the described driving devices are driving the described transport rollers (33) turning in clockwise or counter-clockwise rotation.
System according to claim 6, characterized in that, the described driving devices comprises a drive motor, a drive sprocket, a driven sprocket and a chain, wherein the described drive sprocket is installed in a transport roller (33), wherein each of the other transport rollers (33) have a driven sprocket installed, wherein the described drive sprocket is connected to the driven sprockets via a chain, wherein at one end of the transport roller where the drive sprocket is installed, it is connected to a drive motor.
System according to claim 7, characterized in that, the described chain has a tensioning sprocket (35) and that the described tensioning sprocket (35) is installed on the support (30).
System according to claim 6, characterized in that, the described first chute (31) and the second chute have a big top and a small bottom, like an inverted trapezoid shape.
System according to claim 8, characterized in that, the gaps between the center lines of the described transport roller (33) can be finely adjusted.