DE1068459B - Pressure equalization bodies for devices for warm or hot pressing of rubber objects - Google Patents

Description

It is indispensable for a wide variety of purposes, especially for processes in which bodies except the change in their shape should also experience a change in their chemical structure, the Bodies on which the intended changes are to be made, pressure and warmth at the same time or alternately in a certain order. The process is an example of this the hot or hot vulcanization or the production of vulcanized rubber bodies called with a certain shape, which are brought into the required shape by means of pressure and heat.

An inconvenience that occurs in general for pressing processes and in particular for hot pressing processes, namely the uneven transfer of the pressure introduced into the pressing device to the material to be pressed, which in the latter process usually also results in an uneven heat transfer As a result, attempts are made to remedy this in a known manner by placing between the pressing device and the material to be pressed is a pressure compensation device, usually in the form of an elastic one in a certain sense Pillow, switches.

It is easiest to use the pressing device, e.g. B. a press plate, also at the same time as a heating device to train, so to make the press plate to the heat transfer medium. This simple design however, has the major disadvantage that the heat yield is very low and the heat transfer efficiency is very low it becomes very bad, which is easy to see when you consider that not only the heat radiation of the press and heating plate is lost upwards, but also between the press and heating plate connected pressure equalization body consumes a considerable part of the introduced heat.

There are therefore also known devices to remedy this evil in which the Heater has been relocated to the pressure equalization body, but these devices could also do the one described Disadvantage only in an imperfect way, because it makes sense that in this way a considerable amount of heat is still not directed towards the material to be pressed, but into it Direction of the printing plate, so this undesirably heats up.

According to the invention, which relates to the formation of a pressure compensation body for devices for Warm or hot pressing of rubber articles with a heating device included in it the disadvantages described avoided. The new thing in the training of the pressure compensation body is seen in the fact that a subdivision of the pressure compensation body which promotes the conduction of heat to the material to be pressed for fixtures

for hot or hot pressing

of rubber articles

Applicant:

Stählgruber, Otto Gruber & Co.,
ίο Munich 8, Rosenheimer Str. 17

Willi Graber, Fürstenzell near Passau,
has been named as the inventor

is made of the same body in layers of different thermal conductivity.

In the drawing, the prior art is according to the introduction to the description and an embodiment the device according to the invention, for example, where means

1 shows a pressing device for hot pressing with pressure compensation, representing the prior art, 2 shows a device according to the invention for hot pressing with pressure compensation in section.

1 shows a press plate or a press ram which is designed as a heating device at the same time is what through the supply cable 2 and the connector 3 of an exemplary electrical heating device is illustrated. The product to be pressed warm or hot is shown at 4. Between the Pressing and heating plate 1 and the material to be pressed 4, the pressure compensation body 5 is placed between them.

The amount of heat Q introduced into the heating plate is distributed if, for the sake of simplicity, the difference in the heat gradient between the ambient air and that of the pressure compensation body is neglected, such that about half radiates upwards and half downwards onto the pressure compensation body. Only part of the amount transferred down from the underside of the heating plate to the pressure compensation body

* 5 Amount of heat Q ₁ is in turn transferred to the pressed material as amount of heat q ₂ , since a considerable part of the amount of heat q _t introduced into the pressure compensation body is also radiated to the sides and upwards into the ambient air.

The device according to the invention, however, consists of an unheated pressing device, for. B. a press plate 6, and a heated pressure compensation body interposed between this and the material to be pressed 4 7 of special design.

Claims (6)

The pressure equalization body 7 contains the heating device, for. B. in the form of heating coils or heating cartridges 8, with supply cable 8 α and is thus divided into two sections. One of these sections, namely the section 9 on the press plate side, is designed to be heat-insulating in order to prevent heat dissipation in an undesired direction as far as possible, while the other section, namely the section 10 on the pressed material side, is designed to be thermally conductive. In this way, the heat is directed in such a way that essentially all of the heat introduced into the heating device is transferred to the material to be pressed, which fact is illustrated by the heat arrow Q 'and the heat arrows Q " It has been shown that the formation of the part of the pressure compensation body located after the press plate as a pure rubber body or the addition of asbestos to the substance forming the main constituent of the pressure compensation body, such as rubber, elastic plastic or the like. The lower part on the pressed material side is made thermally conductive by adding, for example, an admixture of carbon black or metal powder, in particular light metal powder, to the main raw material of the pressure compensation body. 1. Pressure compensation body for devices for warm or hot pressing of rubber objects with heating device contained in it, characterized in that one of the heat conduction Subdivision of the pressure compensation body into layers promoting the pressed material different thermal conductivity is made. 2. Compensating body according to claim 1, characterized in that the part on the pressed material side is particularly is designed to be a good heat conductor. 3. Compensating body according to claim 1, characterized in that the facing away from the material to be pressed Part is designed to be heat-insulating. 4. Compensating body according to claim 1 to 3, characterized in that the part on the pressed material side thermally conductive, the overlying part facing away from the pressed material is designed to be thermally insulating. 5. compensating body according to claim 1 to 4, characterized in that the different in sections Thermal conductivity subdivided body essentially made of rubber or elastic There is plastic, the insulating layers insulating means, for. B. asbestos are mixed in, while the pressed material-side layer or layers are thermally conductive mixtures, e.g. B. carbon black, metal or Contains light metal powder, mixed in. 6. compensating body according to claim 1 to 4, characterized in that the insulating part of the Pressure equalization body above the heating device made of pure rubber or a mixture with a high proportion of pure rubber. Considered publications:
British Patent No. 645 688. 1 sheet of drawings I 909 647/396 10.