FI95006C - Continuous working pressure - Google Patents

Description

95006 5

Continuous press Kontinuerligt arbetande press

The present invention relates to a continuous press for the production of particle boards, fibreboards, plastic sheets, plywood boards and the like by means of flexible endless steel strips by means of accompanying roller bars which are guided transversely to the direction of travel of the strips and which rotate against the heating plates arranged on the press tables.

Such continuous chip presses are known from DE-A-37 43 933 as hot-plate press systems in which heating zones are formed by longitudinal bores extending across the conveying direction of the material to be pressed, so that a different temperature profile can be adjusted. In this case, for example, in connection with the elevated temperature, better internal and outward steam removal of the material pressed into the middle of the heating plate by means of the increased steam pressure and the desired centralized heating of the material to be compressed can be achieved by producing narrower chipboards. When wide chipboards are made smaller, the energy consumption is lower and the main power of the steel strip (different thermal thermal expansion) can be equalized.

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However, the heating plates simultaneously act as a rotating support for the rack bars. Based on them, the transitions have been implemented toothed accordingly. The displacements of the three .. heating plates are thus provided with a gap according to the thermal expansion.

In this case, partially high surface pressures are created on the rod bars in the transition area of the next heating plate of one heating plate 30, whereby the specific surface pressure allowed for sealing the chip cake, especially in the high pressure area of the press, is further minimized so that only transition pressures in the range of about 30 bar are allowed. Technologically, however, pressures of max. 50 2 95006 bar. The fan-shaped zigzag displacements in the transition region still cause very high manufacturing costs in connection with the manufacture of longitudinally drilled heating plate mounting connections. According to DE-A-37 43 933, the object and purpose of longitudinally drilled heating plates are to produce narrower chipboards on the basis of the desired central heat transfer. It could also take advantage of the fact that higher sealing pressures based on a narrower width can be used for boards with a higher bed density. However, this cannot be exploited on the basis of limited allowable specific pressures. When continuous presses are used in practice, the use of such heating plates has the effect that, after only a few hours of operation, about 3000-6000 hours, the support surfaces wear hard. This wear does not so much lead to a general weakening of the bearing surfaces, but to the transverse direction (with its ridges and corrugations) corresponding approximately to the distance between the rudder bars in the direction of flow. In this connection, there is then a higher operating noise, which thus leads to critical vibrations of the entire compression system with increasing wear.

According to DE 40 10 308, the latter disadvantages are avoided by introducing unwinding plates on the unwinding surfaces of heating plates with a thickness of 20 7-23 mm and a brinell hardness of 250 or higher, the unwinding plates being mutually heat-treated and / or heat-treated and / or wherein the plurality of unwinding plates are tracked on the pressing surface in each case by means of a stretch seam separated from each other and into the sawtooth joint one after the other. For the benefit of the DE patent, it is to be considered that the increased surface hardness of the unrolling plates provides an ideal support for the bar bars. Since no wear occurs on the surface, such as: when supported directly against the heating plates, a longer service life of the buffers themselves can also be expected. The unobstructed unwinding of the bead bars on the unwinding plate also promotes precise adjustment of the advance of the steel belt. Due to the effect of the hydraulic compressive forces 30, the partially topographically elevated surface pressures can be adjusted to a range of about 250 bar, i.e. by means of the hardened unwinding plates according to the patent publication, the pressing system is made economically advantageous in duration and thus 3 95006 fully operational.

It is an object of the invention to further develop the press according to DE 40 10 308 in such a way that a different temperature profile can be adjusted to the longitudinal center of the pressing surface without increasing the cost of manufacturing longitudinally drilled heating plates and fully preserving the advantages of the solution.

This object is achieved according to the features and measures according to the characterizing part of claim 1.

Together with the solutions according to DE-A-37 43 933 and DE-A-40 10 308, the above-mentioned disadvantages are avoided and compensated for in an advantageous manner according to the invention.

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Appropriate additional features of the subject matter of the invention are set out in subclaims • I 2-4.

The press according to the invention will be described in more detail by means of a drawing and an exemplary embodiment.

·· The drawing shows the following:

Figure 1 is a schematic side view of a continuous press,

Fig. 2 is a section "G" of the press of Fig. 1, 304 95006

Fig. 3 is a plan view "X" of the unwinding plates of Fig. 2,

Fig. 4 is a temperature-time-flow diagram with temperature profiles, and Fig. 5 shows the lower table and the upper table of the press without the unrolling plates.

According to Figure 1, the continuous press consists of a lower table 2, a movable upper table 3 and drawbars connecting them (not shown). To adjust the compression gap 4, the upper table 3 is moved back and forth by hydraulic cylinder devices (not shown) and 10 is stopped in the selected position. The steel strips 5 and 6 are guided through the drive drums 7 and 8 and the reversing drums 9 and 10 around the lower table 2 and the upper table 3. In order to reduce friction between the heating plates 11 arranged between the lower table 2 and the upper table 3 and the surrounding steel strips 5 and 6, a pile rod mat formed from the pulleys 1 is also arranged in a circumferential manner. The shank bars 1, the shafts 15 of which extend transversely to the strip passage direction, are connected together on both longitudinal sides of the press to guide chains 12 with predetermined pitches and led to heating plates 11 from the top table 3 and the bottom table 2 through the strips

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Figures 2 and 3 are a section D-D of section G of Figure 1, illustrating the placement of the unwinding plates 13 on the heating plates 11 of the lower table 2. In this connection, the unwinding plates 13 are screwed against the heating plates by means of screw connections 14 and 18. The unwinding plates 13, on the other hand, are initially fastened in the forward direction 25 by means of fastening bolts 15 as a fixed point for the heating plates 11.

The transitions from one unwinding plate 13 to another are formed by a sawtooth joint. si 19 and can be arranged in a trapezoidal or circular arc, in which case the expansion seam 17 must also be observed in the compensation of thermal expansion.

Figures 4 and 5 show the pressing surfaces consisting of the heating plates 11 at the inlet, the heating plates 1Γ in the central part and the heating plates 11 ”at the outlet end of the press. As shown in Figure 4, the temperature-time

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5 95006 is shown in the diagram, the temperature profile is constructed for the temperature impulse in the heating zone a at the inlet, the falling temperature in the heating zone b and the lower temperature in the heating zone c at the outlet end. In order to adjust the temperature profile across the longitudinal direction or direction of travel of the heating plates 11, 11 'and 11 ”5 of the continuous press, the heat carrier bores 16 are arranged in the longitudinal direction, the longitudinally arranged heat carrier bores 16 being distributed transversely to different heating surfaces I-VI. -VI can be adjusted separately, eg for temperature level F. The letter "e" indicates the width of the material to be pressed.

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By means of a hydraulic and / or electric control device, the temperature level F can be controlled by means of temperature sensors 11, 11 'and 11 ”depending on the width e of the material to be pressed by connecting or connecting the individual heating surfaces I-VI or by conducting a differently heated heating medium 15 to the heaters 11. The temperature profile F can be realized from the longitudinal sides BB to the longitudinal center AA with a rising temperature. The temperature management in the longitudinal direction of the press arranged to take place lämmönkanninporauksiin 16 heating plates 11,11 'and 11' by means of conductors 21 which are located on steel tracks the opposite 5 and 6 of this 20 vertically relative to the rear side of the kuumennuslevypintaan. Thus, the required heating energy can be desirably applied only in the area of the width e of the material to be compressed, whereby, as described above, the corrugation of the strips is avoided and at the same time thermal energy is saved, because less radiant heat is wasted.

According to the invention, the heating plates 11 below or above the unwinding plates 13 in the butt 20 ·· between the individual heating zones a, b and c can be arranged without a sawtooth connection. By means of a straight butt 20, as shown in particular in Figures 2 and 3, the heating plates 11 can be arranged in a known manner in a relatively simple manner in the heating medium circulation 22. The supply and discharge lines 21 are arranged vertically from the outside on the plate buffer edges 20 in a simple manner. Together with the unwinding plates 13, the heating plates 11 do not have to be technically connected in the transitions, e.g. in the region of zones a and b or b and c 6 95006 in the region of the buffer edges 20 - which was previously common - because no fan-shaped transitions are required. Temperature conduction can be implemented via a flat buffer 20, in particular to the transition zone, substantially more accurately, since the transition range is substantially smaller, i.e.

5 the conduction of the temperature takes place in a concise manner, more precisely, transversely and longitudinally with respect to the heating plates.

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Claims (5)

7 95006 A continuous press for the production of particle board, fibreboard, plastic board, plywood board and the like by means of flexible endless steel strips (5, 6) which transmit the compression pressure and pass the material to be pressed, guided by drive drums (7, 8) and reversing drums. 10) by means of a fixed (2) correspondingly movable (3) press table and which, to be adjusted by the pressing slot (4), rest against the press tables heating plates (11) by means of accompanying roller bars (1) guided transversely to the direction of travel of the strips (5, 6); rotating against heating plates (11) arranged on press tables (2,3), characterized in that rolling surfaces (13) with a thickness of 7-23 mm and a Brinell hardness of 250 or more are arranged on the winding surfaces of the heating plates (11) and are heat-treated on both sides and / or tempered to ensure that both sides are used a plurality of winding plates 15 (13) arranged in succession on the pressing surface by means of sawtooth-shaped joints (19) and intermediate expansion joints (17), that the heating plates (11) are provided with straight butt joints (20) channels (16) and that the heating carrier channels (16) are connected to a plurality of differently heated heating surfaces (I-VI). Continuous press according to Claim 1, characterized in that its temperature is controlled so that the heating surfaces (I-VI) of the heating plates (11) have a decreasing temperature level (F) from the longitudinal centerline (AA) to the longitudinal sides (BB) of the press. the same temperature in the transverse direction depending on the width (e). • · Continuous press according to Claim 1 or 2, characterized in that the heating surface 30 of the heating plates (11) successively arranged on the press tables (2,3) is divided into a plurality of heating zones (a, b, c) into which different amounts of thermal energy can be supplied. 95006 8 Continuous press according to one of Claims 1 to 3, characterized in that the individual heating surfaces (I-VI) of the heating plate (11, 11 ', 11') are provided at the butt joints (20) between the heating plates via supply lines (21) arranged perpendicularly. and outlet connections for the heating-5 and / or cooling medium. «M li 9 95006