FI69590C - SAETT VID TILLFOERSEL AV VAETSKA TILL EN BAEDD AV TRAEPARTIKLAR AVSEDDA ATT PRESSAS TILL SKIVOR SAMT EN ANORDNING GENOMFOERANDE AV SAETTET - Google Patents

Abstract

A method for supplying a liquid to a mat (11) of wood particles to be pressed to boards and a device for carrying out the method. Finely divided liquid, e.g. water or a wax dispersion, is supplied to the mat (11) synchronous with the deposition of wood particles from the forming station (10). The same amount of liquid per unit of surface of the mat will be supplied as the liquid is fed to the mat (11) synchronous with the deposition of wood particles from the forming station (10). A device for carrying out the process comprises a forming station (10), equipped with nozzles (17a, 17b) for liquid and outlet means, which are arranged in such a manner, that liquid will be fed from the nozzles (17a, 17b) simultaneously with the operation of the forming station (10).

Description

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(51) Kv.ik.4 / lnt.Ci.4 B 27 N 3/18 SUOMI' — FINLAND (21) Patent application - Patentansökning 792109 (22) Application date - Ansökningsdag 0 ^ 4.07 - 79 (23) Start date - Giltighetsdag 04.07. 79 (41) Became public - Blivit offentlig 15.01 .80

National Board of Patents and Registration (44) Date of publication and publication. - 29 1185

Patent- och registerstyrelsen '' Ansökan Utlagd och utl.skriften publicerad (32) (33) (31) Privilege requested — Begärd priority 14.07.78 Sweden-Sweden (SE) 7807865-8 (71) AB Casco, Box 11010, 100 61 Stockholm, Sweden-Sverige (SE) (72) Jan-01of Andersson, Kvissleby, Sweden-Sverige (SE) (74) Oy Jalo Ant-Wuorinen Ab (54) Method for conducting a liquid into a sheet of wood parts pressed into sheets and a device for carrying out the method - Sätt The present invention relates to a method for conveying a liquid by means of liquid supply means in a constant amount per unit time to for a carpet conveyor, which spreading station moves along the carpet conveyor from the initial position to the end position while simultaneously spreading the wooden parts and then returns to the initial position without spreading. The present invention also relates to an apparatus for carrying out the method.

In the production of sheet material, for example particle board from wood parts and the like, the chip and / or fibrous smaller cellulose-based particles are glued with curable binders and formed into a non-particle mat by means of an application station on the carpet base. The carpet base may be an endless belt or it may consist of separate pressure plates, which in turn are conveyed by an endless belt. The chip mat thus formed is then fed to a hot press, possibly after passing through a device for dividing the chip into parts to be pressed. The press may be of the single-layer type, of the multilayer type, or it may be of continuous use. The heat and pressure of the press 2 69590 hardens the binder in the glued chips, forming a sheet-like material.

In order to obtain reproducible results during curing, it is essential that the moisture content of the chips be of a certain value, which can be adjusted according to the binder used, and generally does not exceed 14% by weight. During the heat treatment in the press, the steam generates an impact effect which shortens the pressing time. If the moisture content is too high, this steam jet can cause the compressed chip material to explode.

The best result is obtained when uniformly moistened chips are sprayed on the upper and / or lower surface with water or an aqueous dispersion containing surface-modifying additives such as an iridescent agent or a hydrophobizing agent before pressing.

Prior art methods for feeding liquid are based on the principle that the liquid is applied when the cutting mat is transferred to the press. When the liquid flow is constant, the amount of liquid per unit area of the chip mat will depend on the transfer rate of the layer. A method of this type is disclosed in GB 1 344 049. Variations in velocity result in the amount of liquid per unit area becoming variable. For example, when starting and stopping the carpet conveyor, too much liquid gets on the upper and / or lower surface of the carpet due to the acceleration and deceleration of the carpet conveyor. For this reason, uneven curing occurs during the compression step due to the change in the vapor effect depending on the moisture content of the heated material. In addition, there are variations in the surfaces of the finished sheets due to uneven dosing in the case where the fed liquid contains surface modifying additives.

Various experiments have been performed to eliminate these disadvantages. Thus, for example, there is a device disclosed in Swedish patent publication 398 075, in which the dosing of the liquid is adjusted by sensing the speed of the carpet conveyor.

According to the present invention, the problem of evenly distributing liquid on the upper and / or lower surface of the unmounted machine is solved by moving the liquid supply members synchronously and simultaneously with the application station and feeding a constant amount of liquid per unit time at least to the other side of the mat. when the application station returns to its initial position, the liquid supply is cut off.

The invention can be applied in any type of application station for a chip or fibrous material in which it is desired to spray the sheets with a liquid. Important applications are the production of fibreboards and especially particle boards. Spreading stations can be of several different types. In the production of fibreboards, the board is often taken from suspension and the purpose of adding the liquid is then primarily to add surface-modifying additives. The material can also be applied dry or mixed only with glue and other additives. The material can then be applied directly as a mat of limited length, usually in several layers of different material quality, or as a longer mat by swirling the material and applying it to a special space provided with a fan. The invention is described below mainly for the purpose in which the chipboards are manufactured by applying dry or only moistened chips to a conveyor, which is the main application of the invention.

The application station for the manufacture of the chip mat, which is located in connection with the mat conveyor, is adapted to produce a uniform chip mat in all conditions of use. This device is subject to high accuracy requirements because uneven finished mat material does not produce a satisfactory finished sheet material. For example, when the spreading station is mobile, moving from the end position to the extreme position while spreading the chips and then returning to the end position without spreading the chips, it is driven by a drive motor, while the chips are spread by a separate motor. During the chip application phase, the amount of chips to be applied must be constant while the drive motor must move the application station at a constant speed. Even the slightest deviation from the predetermined operating conditions inevitably results in a variation in the thickness of the applied uncut, which in turn causes the bulk density of this uncut to become irregular during the compression step, which can lead to rejection of the article.

By arranging the liquid supply means according to the present invention in fixed connection with the application station, they move at the same speed as the station, which according to the above must move at a constant speed in order to obtain a uniform chip. Because the dosing of the liquid takes place synchronously with the use of the application station, the dosing of the liquid is even on the entire surface of the non-cutting machine. Thus, a uniform liquid distribution is obtained over the entire upper and / or lower surface of the uncut, which is completely independent of the uneven speed of the carpet conveyor during starting and stopping.

According to a suitable embodiment, the use of the liquid dosing equipment is started synchronously with the chip spreading motor in the spreading station, because the liquid supply is timely only during the chip spreading phase and not when the spreading station returns to its end position. However, it is within the scope of the invention that the liquid dosing means is started synchronously with the drive motor of the application station, provided that suitable cut-off means are installed in the device to ensure that dosing does not take place when the application station returns to its end position.

The fact that, according to the invention, the liquid supply means must be fixedly connected to the application station means that no significant time lag must occur between the application of the application station and the movement of the liquid supply means, which means that these members can be spaced from the application station. However, it is most suitable that the members are fixedly mounted in the application station. In certain cases, the carpet conveyor can also move during application with the application station being movable, which is also within the scope of the invention.

In this method, the liquid is usually dispensed in a finely divided form by means of spray nozzles. The liquid may also contain, in a known manner, other additives used in the preparation of the sheet material, such as surface treatment agents, for example wax dispersions, polishing agents, anti-caking agents, agents for controlling the hardening of glued chips or formaldehyde-collecting agents. According to the invention, liquid can be added to the upper and / or lower surface of the uncut depending on whether the liquid supply means are located on one side and / or on both sides of the carpet conveyor.

The position of the nozzles relative to the application station when applying continuous tracks is not critical as long as their movement with respect to the mat is the same as that of the station.

5 69590 For practical and space reasons, it is best to place the nozzles as close as possible to the chip application point. However, the space required by the chip applicator in the longitudinal direction of the mat is relatively large, especially when the chips are vortexed before application and if the mat surface or both surfaces are to be sprayed, the nozzles must be located outside the chip application area and thus substantially away from the chip feed center. As the spreading station moves relatively over the carpet, the nozzles for spraying the carpet conveyor, the chip spreading means and the nozzles for spraying the upper surface of the carpet over different areas of the carpet then move.

However, after recovery and during relative movement over the new mat, both the chipping and spraying of the chips continue from where they were previously stopped, providing a continuous coating of both chips and liquid along the path. Normally, both chip application and liquid spraying are so well regulated that there are no splices that adversely affect the final board quality. If the mat is partitioned before compression by forming a chip-free gap between the panels to be made, this division can therefore normally be carried out independently of the splices between the application and spray areas and usually the chip application extension comes somewhere in the middle stages of the finished plate. In case there are difficulties in distributing the liquid evenly in the liquid injection joint between different reciprocating movements or if the uniformity requirements are particularly high, the conditions can preferably be arranged so that the gaps between the plate parts are formed by removing material at the injection gaps.

The liquid supply means may be known devices for dispensing liquid, for example nozzles or nozzles, and must comprise a plurality of fine nozzles or mouthpieces, the number of which is adapted to the width of the cutter, the spray angle and the height of the device above the cutter. The purpose of the location is to achieve an even distribution of the liquid in the width direction of the mat, which can be difficult to implement given that the amount of liquid fed is in most cases relatively small. The spray areas of the nozzles must be arranged so that they partially overlap.

According to a particularly suitable embodiment, nozzles giving an oval spray pattern are used, the long axes of the ovals 6 69590 being oriented in the transverse direction of the mat so that the overlapping areas of the spray patterns can be enlarged without increasing the length of the jets in the longitudinal direction of the mat. The extent of the spray pattern in the longitudinal direction of the mat shall be such that it is not so large that a uniform distribution over the entire surface can be achieved and that small variations in relative movement between the mat and the nozzles, especially between joints, cause large variations in application rate. . A suitable width of the spray pattern of the nozzles in the longitudinal direction of the mat is 5-50 cm, more preferably 10-30 cm.

The liquid can be supplied by compressed air via a dosing pump or other type of known dosing device comprising a pressure equalization vessel and solenoid valves. In order to achieve the most uniform dosing, the dosing pump must be of the type with a relatively constant volume supply, regardless of the back pressure, and can be, for example, a diaphragm pump. Special pressure equalization vessels are sometimes unnecessary, for example when the flexibility of the conduit systems is so great that they may contain a certain amount of pressurized fluid. Solenoid valves are most suitable because they respond quickly to opening and closing pulses. They should be placed as close as possible to the nozzles to ensure the fastest response. The dosing elements and any solenoid valves are preferably operated electrically so that they operate at the same time as the applicator spreads the chips. Chip application is normally started a few seconds before the relative movement of the application station and the mat begins to eliminate the effect of wastage times, and it has often been found appropriate to start the nozzles simultaneously with chip application. However, the adjustment and selection of start and stop points must be performed individually for each device.

The present invention also relates to an apparatus for carrying out the above method, and comprises a mobile application station, at least one side of which is provided with liquid supply means, the drive of which operates synchronously with the application station. According to a suitable construction, both non-cutting sides of the application station are provided with liquid supply means, preferably spray nozzles or spray nozzles. The sprayers on both sides of the application station are operated by means of a metering pump via a solenoid valve located in the corresponding supply line and the pump and solenoid valve.

II

7 69590 bricks are connected to operate simultaneously with the spreading station drive to spread the chips. Preferably, a double-dosing pump is used, in which each half feeds the feed members of its own side.

The invention will now be described schematically with reference to the drawing, which, however, does not limit the invention. The drawing is a side view of an apparatus for producing particle boards, which application station is provided with and connected to liquid dispensing means according to the invention.

The carpet conveyor 1 consisting of an endless belt is guided around the folding rollers 2, 3, 4 and 5. Guide roller 4 driven by a motor 6 in the direction of the arrow. The upper part of the carpet conveyor 1 can be passed through the hot press 9. screening by means of the forming station 10, which may be replaced by any known application station, the conveyor mat formed Melle-chip mat 11. The application station 10 passes through the rollers 14 along the rails 15, and then moves to end positions of the drive motor 10a in the direction indicated by the arrow 12. Simultaneously with this movement, the chips are applied to the mat by means of a chip application device 13, which is also driven by a motor 13a.

On both sides of the application station 10, which face the carpet conveyor 1, there are fixedly mounted spray nozzles 17a and 17b connected to a dispensing device 18 comprising a double-diaphragm pump which receives liquid from the production vessels 19a and 19b. Measuring glasses 20a and 20b are mounted on each connecting line and are connected via three-way valves 21a and 21b. After the pump, a pressure equalization vessel 22a and 22b and solenoid valves 23a and 23b are connected to each line and to the injection nozzles 17. When the spray nozzles are pneumatically operated, compressed air is supplied from the pump 45 through a filter 46 and a pressure relief valve 49 to the nozzles. The compressed air can either be controlled synchronously with the dosing pump 18 or it can be used continuously.

The dosing pump motor 18a and the solenoid valves are controlled synchronously with the chip spreading device 13 so that the pump 18 starts and the solenoid valves 23 open when the device motor starts. This is achieved by means of a connection 24a and 24b of the motor 13a, the pump motor 18a and the solenoid valves 23a and 23b via the same control switch 24.

When the spreading station has reached its leftmost position, the motor of the chip spreading device is stopped and when the control current to it is switched off, the pump 18 is switched off simultaneously and the solenoid valves 23 are closed, whereby the liquid supply is stopped. The application station then returns to its end position by means of a drive motor without the operation of the chip application device and thus the liquid dosing equipment.

While the application station forms part of the cutting mat, as described above, the press 9 is closed. At the same time, if desired, a chip-free gap can be formed between the compressible mat parts by means of a brush, saw or the like 16 which moves across the non-chip.

After the carpet conveyor has fed the spreading machine to the press to be cut, the spreading machine is restarted at the relative point on the cutting mat where it was stopped in the previous step, whereby the dosing device also starts feeding the liquid. Thus, the spraying also starts at the point where it was previously cut off.

In a continuous device of the type described above, the amount of liquid dispensed in use is adjusted in relation to the thickness of the uncut, i.e. in relation to the speed of the application station. The advantage of this method is that when, for example, it is desired to obtain a thicker mat and thus a thicker sheet material, it is only necessary to reduce the speed of the drive motor of the spreading machine, whereby the thickness of the uncut increases. Since the applicator will then move more slowly, while the liquid dosing equipment still feeds the same amount of liquid per unit time, more liquid is sprayed onto the thicker chipboard without the dosing equipment having to be adjusted separately.

Claims (2)

69590 1. Sätt vid tillförsel av vätska med hjälp av vätske-tillförselorgan i en konstant mängd per tidsenhet account en bädd av träpartiklar eller liknande, avsedd för pressning accounts skivmaterial, där bädden bildas pä en bäddtrransportör av en arkningsstation som röd the account is still under the same deposit as the third party and the third party after the account is received after the deposit, the third party is the same as the account of the third party account and the third party account in the case of a side-by-side position, at the same time as the starting point of the account at the starting position, at the end of the stop. A method of conveying liquid by means of liquid supply means to a carpet of wood parts or the like pressed into a sheet in a constant amount per unit time, the application station forming a carpet on a carpet conveyor. that the liquid supply means move synchronously and simultaneously with the application station and supply a constant amount of liquid per unit time at least to the other side of the mat during the application of the particles from the application station and that the liquid supply is then cut off when the application station returns to its initial position. A method according to claim 1, characterized in that the liquid is fed to the lower and upper surface of the mat so that the liquid supply means are mounted on both sides of the spreading machine on the mat side. A method according to claim 1 or 2, characterized in that the liquid is added when the chip application means of the application station are in operation. An apparatus for carrying out the method according to claim 1, comprising a carpet conveyor (1), an application station (10) moving over and along the carpet conveyor from the initial position to the end position while simultaneously spreading wooden parts or the like to form a mat (11) to be pressed into the conveyor without applying chips, and supply means (17a, 17b) for adding a constant amount of liquid per unit time to the mat of wooden parts on the conveyor, characterized in that the liquid supply member (17) is arranged in close contact with the application station and connected to the control and operating device (18a, 18, 23a, 23b), which, during the application of chips from the spreading station, increases a constant amount of liquid per unit time and then cuts off the liquid supply when the spreading station returns to its initial position. Device according to claim 4, characterized in that each end of the application station (10) is provided with liquid supply means (17a, 17b) and that the control and drive device comprises a dosing pump (18) connected via magnetic valves (23a, 23b) and that the dosing pump motor (18a) and the solenoid valves are connected to operate synchronously with the application station drive (13a) for spreading the chips. Device according to claim 5, characterized in that the liquid supply means (17a, 17b) are arranged at each end of the application station and are directed towards the mat (11), whereby liquid is added to the upper and lower surface of the mat. 2. Sät enligt patentkravet 1, kännetecknat därav, att vitskan tillföres bäddens under- och översida, gen-nom att Vätsketillförselorganen är anbringade pä arknings-