EP0011114A1 - Platen press - Google Patents

Abstract

In a platen press, in particular for the vulcanisation of conveyor belts and for the production of fibre plates, chipboards or the like, having a press table (1), an upper crosspiece (6) and if appropriate a central table (7), as well as heating plates (5) adjoining the latter with insulating plates (3) in between, and if appropriate further heating plates at different levels, the insulating plates (3) have, at least on one of their two surfaces, groove-like depressions (8) extending as far as the edges. The depressions (8) ensure better and more uniform gas removal from the plates when subjected to thermal stressing, because the gases can escape to the outside, with the result that, on the one hand, gas bubble or gas cushion formation between insulating plate (3) and heating plate (5) cannot occur, and, moreover, deformation of the plates is avoided. Furthermore, the groove-like depressions (8) permit an equalisation of thickness differences in the plates due to manufacture, in that they act as compensation zones and take up the material displacement. <IMAGE>

Description

The invention relates to a plate press with a press table, upper spar and possibly a center table and heating plates connected to these with the interposition of insulation plates. Furthermore, further floor heating plates can optionally be provided.

Plate presses of the aforementioned type are used in particular for the vulcanization of conveyor belts and for the production of fiberboard, chipboard or the like. used. The insulation plates have the task of insulating the flow of heat from the heating plates to the upper spar, the press table or possibly also the center table, in order not to subject these parts to excessive thermal stress and on the other hand to essentially provide the heat for the actual pressing process to have.

The insulation panels themselves consist essentially of asbestos, glass fabric and / or poorly conductive fillers. Most of the time, synthetic resins or rubber mixtures modified with rubber, for example silicone, and sometimes also cement, are used as binders. In any case, the insulation plates regularly of such a structure that they can absorb moisture and, accordingly, there is always a certain residual moisture in the plates.

This residual moisture and also the fact that the binder combinations with the exception of cement under pressure and heat in gaseous form separate residues of, for example, phenol, cresol or also formaldehyde, whereby depending on the stress and heat pressurizing overcondensation both lead to the insulation plates deform essentially concave or convex and lose strength and dimensional stability.

It is also known to piece together the insulating plates, which can be square or rectangular, in very large press tables, so that an insulation plate consists of several partial plates. In particular with such partial panels, certain differences in thickness cannot be avoided in terms of production technology. These inaccuracies in thickness lead to so-called tip carriers, which are subjected to a higher specific load and are also subjected to a higher thermal load.

Accordingly, there is on the one hand the task of preventing the uneven tensioning or deformation and even destruction of the insulation plates which occurs due to the residual moisture etc. and, moreover, of compensating for thickness inaccuracies, particularly in the case of partial plates.

This object is achieved in that the Isolation plates have at least on one of their two surfaces to the edges groove-like depressions. In the event of thermal stress, these depressions ensure better and more even exhausting of the plates, because the gases can escape to the outside, so that on the one hand there can be no gas bubbles or gas cushion formation between the insulating and heating plates and, in addition, the deformation of the plates is avoided. In addition, the groove-like depressions enable the production of differences in the thickness of the panels due to production, in which they act as compensation zones and absorb the material displacement.

According to a further feature of the invention it is provided that the groove-like depressions on the hotplate side. are provided on the surface of the insulation plate, i.e. So in the area of the greatest heat exposure. This also ensures a particularly favorable outflow of the gas.

Furthermore, according to the invention, the groove-like depressions should be arranged in a grid-like manner on the insulating plates. This achieves an advantageous division in terms of area, so that, on the one hand, the differences in thickness are compensated extremely favorably and, in addition, a multiplicity of gassing channels are formed. This is ensured particularly well if the distance between the groove-like depressions is approximately 50 to 200 mm.

To prevent slipping in the embodiment in which the insulation plate consists of several partial plates prevent, it is further provided that spacer crosses are arranged between the partial plates. In this case, the spacer cross arms can expediently be shorter than the edge length and / or thinner than the thickness of the partial plates. As a result, additional exhaust gas spaces or exhaust gas channels and compensation zones for the differences in thickness of the partial plates are formed.

• Fig. 1 in schematisch gehaltener perspektivischer Darstellung eine Plattenpresse mit Mitteltisch und
• Fig. 2 ebenfalls in perspektivischer Darstellung vier nebeneinandergelegte Teilplatten mit Distanzkreuzen in vergrößerter Darstellung.

In the drawing, the invention is illustrated in more detail using an exemplary embodiment. Show it:

• Fig. 1 in a schematic perspective view of a plate press with center table and
• Fig. 2 also in a perspective view four partial plates placed next to each other with spacer crosses in an enlarged view.

1, the plate press has a press table 1, which can be raised and lowered via a cylinder piston arrangement 2. On the press table 1, an insulation plate, designated as a whole by 3 and consisting of several partial plates 4, is initially arranged. The actual heating plate 5 is located above the insulation plate 3.

The press also has an upper spar 6, which is arranged in a stationary manner on the press part (not shown) as an abutment. In the same way as on the press table 1, an insulating plate 3 comprising a plurality of partial plates 4 and a heating plate 5 are provided on the upper beam 6.

Finally, the plate press also has a center table 7 which is equipped with insulation plates 3 and heating plates 5 on the top and bottom.

The insulation panels 3 and the sub-panels 4 are, as can be seen in particular from the enlarged representation according to FIG. 2, provided on one surface with groove-like depressions 8 which cross the sub-panels 4 orthogonally like a grid and are arranged such that their openings each to the Point heating plates 5.

So that the partial plates 4 cannot slip against each other, spacer crosses 9 are also provided, which are each arranged between four partial plates 4 and hold them at an exact distance. Slipping of the partial plate 4 against one another is not possible. For the sake of clarity, the spacer cross 9 is shown highlighted in FIG. 2. Since the spacer cross arms can be both shorter than the edge length and thinner than the thickness of the partial plates 4, additional channels 10 are formed.

Between the press table 1 and the center table 7 as well as the upper beam 6 and the center table 7, further heating plates - without insulation plates 3 - can of course be provided to form several pressing days. On the other hand, only a single-day press can be used, in which only one press space is provided between the upper beam 6 and the press table 1. Finally, multi-daylight presses without a center table, where the other floors consist exclusively of heating plates, can also be used.

Claims (7)

1. Plate press with press table, upper spar and possibly a center table, as well as heating plates connected to this with the interposition of insulation plates, and possibly further multi-layer heating plates, in particular for the vulcanization of conveyor belts and for the production of fiberboard, chipboard or the like. characterized in that the insulation plates (3) have at least on one of their two surfaces groove-like depressions (8) reaching to the edges. 2. Plate press according to claim 1, characterized in that the groove-like depressions (8) are provided on the hot plate side on the surface of the insulation plate (3). 3. A plate press according to claim 1 or 2, characterized in that the groove-like depressions (8) are arranged in a grid-like manner crossing one another on the insulating plates (3). 4. Plate press according to claim 3, characterized in that the distance between the groove-like depressions (8) is approximately 50 mm to 200 mm. 5. Plate press, in particular according to one of claims 1 to 4, in which the insulation plates consist of partial plates, characterized in that spacer crosses (9) are arranged between the partial plates (4). 6. Plate press according to claim 5, characterized in that the spacer arms are shorter than the edge length of the partial plates (4). 7. Plate press according to claim 5 or 6, characterized in that the spacer arms are thinner than the thickness of the partial plates (4).

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