DE202005009342U1 - Method for applying moisture to fibre board before pressing has hinged slats pressing onto the board and applying water spray immediately before entering the press process - Google Patents

Abstract

A method for applying moisture to fibre board material before pressing has hinged press slats (1, 2) each side of the material flow to compress the board slightly and apply water spray (3) onto the expanding material (8) for improved absorbtion. The slats are positioned close to the entry into the press operation where the absorbed moisture is rapidly turned to steam and enhancing the action of the bonding agent. At least one of the slats is on an adjustable mounting to match different sizes of board.

Description

The The invention relates to a device for one or both sides spraying a Pressgutmatte made of binder mixed with wood or other cellulosic Fibers with steam or water for the purpose of moistening and heating.

to Capacity increase can in the production of fiberboard, as well as in other wood-based panels, the pressed material mat in front of the hot press preheated Be sure to start the glue curing right at the beginning to move the subsequent pressing process and thus the pressing time To shorten. The success of preheating is bigger and higher and higher the faster the temperature increase in the middle of the pressed material mat he follows.

The The desired goal of shortening press time can be achieved directly by temperature increase the mat before pressing or indirectly achieved become. Direct methods are, for example, the mat warming means electrical energy or by flowing through the mat with steam and / or Hot air. The indirect method is to use the two outer layers of the Mat moistens and thereby the actual acceleration process laid by evaporation in the press.

For the direct way of increasing the temperature, various devices are known from the patent literature and the general application practice, which are used for preheating. For example, in the U.S. Patent 4,018,642 as well as in the publications DE 10157601 A1 and DE 19718772 A1 described the generation of heat by means of microwave or high frequency energy. Furthermore, it is off DE 10161341 A1 a steamer is known with which the mat is applied over the entire surface of the hot press with saturated steam. A variant of this method describes the patent DE 19701596 C2 , in which the mat is traversed by an air-conditioned fluid of air and water vapor. All these devices have the particular disadvantage that they are very space consuming and have a high energy consumption. In the full-surface steaming the temperature increase over the mat cross-section is bought by the disadvantage that the moisture in the whole mat cross-section increases, resulting in technological problems and counteracts the desired press time reduction.

at Evaporated the indirect method by wetting the topcoats the water on the surface at the touch with the hot Sheet steel of the press. The steam wanders towards the middle of the mat, condenses on the cold ren Fiber particles and heated thereby the pressed material. This so-called steam effect comes to a standstill when all moisture in the top layer area has evaporated. One further increase in temperature takes place by heat conduction from the hot steel sheet on the pressed material. Since wood and cellulosic substances are good heat insulators and thereby constitute poor conductors of heat, causes the steam shock effect a strong acceleration of the press heating. As a side effect of Cover layer moistening achieves a plasticization of the cellulosic Fiber and a bulk density increase the topcoat, which is usually for fiberboard of great Advantage is.

The Topcoat moistening on the top surface of the mat is normally unproblematic. Because the fibers glued and in some cases with Swell protection requires absorbing the moisture a certain amount of time, so that these humidifiers in some Distance must be arranged in front of the press. On the lower side However, there is the difficulty of even moistening on the Scattering lying mat surface to achieve. There it comes in the usual method according to experience to the formation of Puddles, so that even moistening the bottom is not reached. In addition, the moistened Fibers for baking on the conveyor belts, what at the belt transfer points to damage the mat surfaces leads. To avoid these difficulties one can count on a three-layered one Mat construction, which involves two separate fiber preparation lines installed and the top layer as in the chipboard production more moist than the middle class. This way, however, is not economical, because the extra Investment and operating costs in no meaningful relation to the benefit stand. Such a method, which is not proven in practice, is described in the published patent application 1194574 described by the German Patent Office. In this procedure will be while the scattering of the layer to be moistened the falling particles sprayed with water.

The present invention is based on the specific object of providing a device with which, especially in the production of fibreboards, both outer layers of the pressed material mat can be evenly moistened immediately before the pressing process, such that both an acceleration of the pressing process by a steam pulse triggered in the hot press takes place, as well as the plasticization of the outer layers is made possible. The special feature according to the invention consists in narrowing the cross-section of the forwardly moving mat when passing through the device at the bottom and possibly also at the top and spraying the front side of the arching of the mat which expands again. By the expanding Fiber layer can penetrate the moisture optimally in the cover layer. Due to the proximity to the press inlet, excess and unabsorbed moisture may impact directly on the hot steel strips and be evenly distributed from there to the pressed material.

A variant is that the patented device only on the Mat base is placed in front of the press inlet and the Dodge the mat upwards with thin fiber mats through Sliding plate is prevented. In this case, the humidification the upper cover layer with commercial moistening happened between pre-press and the actual hot press.

When Moisturizer can be both steam and cold and warm Water can be used. In addition, there is the possibility by adding Chemicals in the humectant, such as diluted acid, a additional To achieve acceleration of the binder hardening. As an accelerator can the usual Harder for urea-formaldehyde glues be used. About that there is also the possibility Spray release agent, which prevent caking on the press plates.

Around variable mat widths without excess steam or hot water outlet to enable is in the device according to the invention provided to limit the moisture outlet at the ends adjustable. This is done in accordance with the width of the mat from the ends Bearing cylinder inserted into the manifold and locked so be that the wetting agent is sprayed only on the fiber mat.

In the 1 illustrated embodiment of the device according to the invention consists of two wing-like, with spray nozzles ( 3 ) bars ( 1 ) and ( 2 ), which directly after the deflection nose ( 11 ) for the conveyor belt ( 10 ) and immediately before the press inlet ( 4 ) are arranged. The press infeed ( 4 ) form the upper and lower deflection drum ( 15 ) and ( 16 ) for the continuously moving heated steel sheets ( 17 ) and ( 18 ). The above the press inlet ( 4 ) located spray bar ( 1 ) is provided with a height adjustment ( 5 ) and thus according to the respective thickness of the fiber mat ( 6 ) are steplessly positioned. Both spray bars ( 1 ) and ( 2 ) are by means of a rotary bearing ( 7 ) as steep as desired, so that any desired degree of matte necking ( 8th ) is possible. The spray nozzles ( 3 ) are located on the front side of the spray bars ( 1 ) and ( 2 ) and are on the front of the mat neck ( 8th ). The moistening agent is supplied via the distributor tube ( 9 ).

2 shows the arrangement of the moistening device in front of the press in plan view. The fiber mat ( 6 ) lies on the conveyor belt ( 10 ) which via the Umlenknase ( 11 ) transfers the fiber mat into the moistening device. The upper spray bar ( 1 ) is via the steam supply ( 14 ) is supplied with a humidifying agent which passes through the spray zone ( 12 ) on the fiber mat ( 6 ). About the width adjustment ( 13 ), the width of the spray zone ( 12 ).

1

Oberer spray

2

lower spray

3

spray nozzles

4

press infeed

5

height adjustment

6

fiber mat

7

pivot bearing

8th

Matteneinschnürung

9

manifold

10

conveyor belt

11

Umlenknase

12

spray zone

13

restricting cylinder

14

steam supply

15

Upper Umlenktrommel

16

Lower Umlenktrommel

17

upper sheet steel

18

lower sheet steel

Claims (8)

Moistening device characterized in that in the manufacture of cellulose-containing fiberboard, the fiber mat is constricted before entering the hot press transversely to the conveying direction by a arranged on the lower side, provided with spray nozzles wing-like beam, and the front side of the re-opening constriction is sprayed with steam , Moistening device according to claim 1, characterized characterized in that in the manufacture of cellulose-containing fiberboard the fiber mat before entering the hot press across the conveyor by a arranged on the upper and lower side, provided with spray nozzles wing-like Bars constricted is, and the front side of the re-opening constriction with Steam sprayed becomes. Moistening device according to claim 2, characterized characterized in that the distance between the wing-like beams to each other adjusted by raising or lowering the top of the bar attached to the mat thickness can be. Moistening device according to claim 1 to 3, characterized in that the wing-like beam is rotatably mounted, so that the constriction is infinitely variable. Moistening device according to claim 1 to 4, characterized characterized in that by telescopic limiting cylinder on adjusted the active spray zone to the respective mat width at the ends of the beam can be. Moistening device according to one of the preceding Claims, characterized in that water is used as humectant becomes. Moistening device according to one of the preceding Claims, characterized in that the humectant hardener as Accelerator is metered. Moistening device according to claim 1 to 6, characterized in that a wetting agent is added to the wetting agent becomes.