SE515273C2 - Methods and apparatus for continuous production of profiled lignocellulosic disc or strand products - Google Patents

Abstract

In a method and an arrangement for continuously producing profiled, lignocellulose-containing board or strip-like products the fibre material is disintegrated into particle and/or fibre form, which are then dried, glue-coated and formed into a fibre mat (3). This is pressed into a board or strip-like product (4) while injecting steam. Prior to pressing, the fibre mat (3) is given a surface profile, which is maintained during the steam injection process, whereupon the surface of the board of strip-like product is compressed with this profile.

Description

515 273 2 The invention will now be described in more detail with reference to the accompanying drawing, which in a schematic longitudinal section shows a plant according to the invention with four different cross-sections drawn on a larger scale.

The system shown in the drawing is based on the system shown in SE 502 272, which describes a continuous steam injection procedure. A forming station 1 is fed to crushed, dried and glued lignocellulosic fibrous material, which is formed there into a atta berm mat 3, which is fed into a steam injection press 2. In this the mat is pressed into a disc-shaped product 4, which is so hardened that it is solid and exhibits a certain strength. In a second step, the surfaces are further densified in a surface densification unit 5. In this process, a sheet with dense surface layers is thus obtained.

According to the invention, this plant is designed so that profiled board or string products are produced in the same two-step process. For this purpose, a milling or scalper roller 6 is arranged between the forming station 1 and the steam injection press 2. With this scalper roller 6, the lignocellulosic, glued raw material in the form of the berm mat 3 with a density between 20 and 200 kg / ma is given a profiled surface structure. For this purpose, the scalp roller 6 has a varying diameter along its entire width. The profile obtained by the cross section of the carpet must largely correspond to the cross section of the finished product. The profiled mat 3, which may be pre-compressed, is continuously transported into the steam injection molding 2. This is provided with a profiled steam roller 7 with the same profile as the scalper roller 6. Here the mat 3 is compressed and hardened into a disc or string 4 with the intended cross-section by injecting saturated or superheated steam into the carpet. In a second step, the surface layers are further compressed by passing the disc or string 4 through the surface densification unit 5 with one or two hot, compressing roller pairs 8 with the same geometric design as the steam roller 7, but with a smaller cross-sectional area to obtain the desired surface compression. The surface temperature of the roller spar 8 can be between 100 and 350 ° C, preferably between 150 and 250 ° C.

The drawing shows the cross section 9 of the formed floor mat 3 before the presentation. The cross section 10 after the scalper roller 6 shows how the upper surface has been projected.

After the steam injection press 2, the disc 4 pressed therein has obtained the cross section 11 and after the surface densification unit 5, in the cross section 12 the surface layer has been given a higher density, but retains the same profile.

With the same technology, you can also achieve proliferation on the underside of the disc. In this case, a scalper roller 6 is also arranged on the other side of the surface mat 3 and the lower rollers 7 and 8 in the steam injection press 2 and the surface densification unit 5, respectively, are then made with the same surface profile over the width as the lower scalper roller.

In some applications it may be of interest to give a higher density to certain parts of the profile, e.g. on exposed peaks. This is made possible by the profile of the rollers 7 and 8 at these points deviating from the profile of the scalper roller 6.

In an alternative embodiment, it can in the first step, ie. In the steam injection press, the disc or strand produced in a continuous division process is divided into several strands, which are then allowed to enter one or more hot roller pairs 8 in the surface densification unit 5. This division process can take place, for example, by sawing.

The invention produces profiled lignocellulosic products in the form of discs and strands of uniform density over the entire cross section and with sealed surfaces, which absorb the same amount of paint over the entire product in a fast and continuous process. In addition, this is done without raw material losses, apart from the small losses that occur at the saw cuts.

Claims (8)

20 25 30 515 273 PATENT REQUIREMENTS A method of continuously producing profiled lignocellulosic board or strand products, wherein lignocellulosic support material is decomposed into particles and / or fibers, dried, glued and formed into a base mat, which during steam injection is pressed into a board or stranded product. by giving the surface mat (3) before pressing a surface profile, which is maintained during the steam injection, whereupon the surface of the board or strand product is compressed. Method according to claim 1, characterized in that the berm carpet is formed with a density of between 20 and 200 kg / ma. Method according to Claim 1 or 2, characterized in that the berm carpet is pre-compressed. Method according to one of Claims 1 to 3, characterized in that the steam-injected sheet or strand product is continuously divided into narrow sheets or strands before the surface compaction. Method according to one of Claims 1 to 4, characterized in that the disc or strand product is given a varying density over the surface. Method according to one of Claims 1 to 5, characterized in that a surface profile is formed on both the upper and lower side of the product. Apparatus for applying the method according to any one of claims 1 to 6 and comprising a forming station (1), an injection press (2) for pressing a mat (3) coming from the forming station (1) into a sheet or string product ( 4) and a surface densification unit (5) for further treatment of said product, characterized in that at least one milling or scalper roller (6) is arranged between the forming station (1) and the steam injection press (2) to provide a surface profile on the surface and that the steam injection press (2) and the surface densification unit (5) are provided with at least each roller (7 and 8, respectively) which is profiled over the width of the roller. Device according to claim 7, characterized in that the steam roller (7) in the steam injection press (2) has the same profile as the milling or scalper roller (6), but that the press roller (8) in the surface densification unit has a profile which at certain extreme points has a larger diameter than the profile of the steam roller (7).