DE102020130334A1 - Cooling method and apparatus for a rubber raw material - Google Patents

Abstract

The present invention relates to a method for cooling a rubber raw material in a mixing chamber (2), comprising the following method steps: - introducing the rubber raw material into the mixing chamber (2) and mixing the rubber raw material in the mixing chamber (2), - introducing a cooling medium into the mixing chamber (2), wherein the cooling medium has a solid or a liquid state of aggregation, - simultaneously mixing the rubber raw material and mixing the rubber raw material with the cooling medium, - evaporating the cooling medium by absorbing heat from the rubber raw material, and - discharging the vaporized cooling medium from the mixing chamber (2).

Description

The present invention relates to a method for cooling a rubber raw material in a mixing chamber and a corresponding mixing apparatus in which the rubber raw material is mixed.

When processing rubber raw material, the raw material, which is usually a mixture of different components, is mixed in one process step.

Mixing is carried out in specially designed mixing apparatus. For this purpose, mechanical power is introduced into actuators, for example rotors, through which on the one hand distributive, dispersive and laminar mixing effects are generated.

On the other hand, mechanical friction is generated during mixing, which leads to an increase in temperature in the material to be mixed.

Due to the comparatively low thermal conductivity of polymers, the heat transport from the inside of the mixed material to the outside is also delayed.

It is therefore an object of the present invention to provide a method for cooling a rubber raw material and a corresponding mixing apparatus.

The object is at least partially achieved by a method according to claim 1.

• - Einführen eines Gummirohmaterials in die Mischkammer. Das Gummirohmaterial wird anschließend in der Mischkammer gemischt.
• - Einführen eines Kühlmediums in eine Mischkammer, wobei das Kühlmedium einen festen oder einen flüssigen Aggregatszustand aufweist. Das Kühlmedium liegt beim Einführen nicht in gasförmiger Form vor.
• - Gleichzeitiges Mischen des Gummirohmaterials und Mischen des Gummirohmaterials mit dem Kühlmedium.
• - Verdampfen des Kühlmediums durch Wärmeaufnahme vom Gummirohmaterial. Die Wärmeaufnahme und das Verdampfen erfolgen während des Mischvorganges. Das Kühlmedium wird nahezu vollständig verdampft. Allenfalls geringe Anteile des Kühlmediums werden durch Adsorption im Gummirohmaterial gebunden und daher nicht verdampft.
• - Ausführen des verdampften Kühlmediums aus der Mischkammer.

The procedure comprises the following procedural steps:

• - introducing a rubber raw material into the mixing chamber. The rubber raw material is then mixed in the mixing chamber.
• - Introducing a cooling medium into a mixing chamber, wherein the cooling medium has a solid or a liquid state of aggregation. The cooling medium is not in gaseous form when it is introduced.
• - Simultaneously mixing the rubber raw material and mixing the rubber raw material with the cooling medium.
• - Evaporation of the cooling medium by absorbing heat from the rubber raw material. Heat absorption and evaporation take place during the mixing process. The cooling medium is almost completely vaporized. At most, small amounts of the cooling medium are bound by adsorption in the rubber raw material and are therefore not evaporated.
• - Carrying out the vaporized cooling medium from the mixing chamber.

In one embodiment, the cooling medium is completely vaporized just when the mixing of the gum raw material is complete. The rubber raw material is thus cooled during the entire mixing process without excess cooling medium remaining or having to be removed after mixing. The amount of cooling medium added can be measured accordingly.

In one embodiment, the temperature of the cooling medium when it is introduced into the mixing chamber is below an evaporation temperature of the cooling medium. The colder the cooling medium is supplied, the more heat can be absorbed by it and dissipated to cool the mixing chamber or the rubber raw material.

In at least one embodiment, the gum base material comprises multiple components. The ingredients may comprise one or more of rubber, natural or artificial hydrocarbons and auxiliaries or additives required for rubber production. The ingredients are in liquid or solid form.

During a mixing process, the components of the rubber raw material are mixed. At the same time, rubber raw material is mixed with the cooling medium by the same mixing process.

In one embodiment, the cooling medium is water in liquid and/or solid form. In other embodiments, the cooling medium is another substance other than water that is suitable as a refrigerant, such as an alcohol or dry ice.

In one embodiment, the coolant is fed continuously into the mixing chamber. In another embodiment, the cooling medium is added in portions at regular time intervals. The cooling medium can, for example, be supplied in liquid form via injection valves or in solid form via a feed flap. In a possible alternative, the cooling medium can be added in liquid or solid form via the loading flap in bags. In all the variants mentioned, the mixer can continue to run while the cooling medium is being added.

The cooling medium almost completely vaporizes at a temperature below the temperature to which the rubber raw material is to be cooled. In at least one embodiment, the cooling medium can be completely absorbed during the mixing process by absorbing heat from the rubber raw material material are vaporized and carried out in gaseous form from the mixing chamber.

In one embodiment, a small amount of cooling medium can remain in the rubber raw material and can be further processed with it in further process steps. The cooling medium can then be expelled in a subsequent process step such as a renewed mixing process (two-stage mixing), an under-machine process (rolling mill, vented extruder) or in a drying process.

In all of the embodiments, however, the essential part of the cooling medium is vaporized during the mixing process and discharged from the mixing chamber in the gaseous state. The major part of the cooling medium therefore does not react with the rubber raw material or one of its components, i.e. no chemical reaction takes place.

Because of the direct contact between the rubber raw material and the cooling medium, heat can be easily transferred from the rubber raw material to the cooling medium. For this purpose, the cooling medium must have a lower temperature than the rubber raw material. A typical processing temperature of the rubber raw material is between 80°C and 200°C. A preferred processing temperature of the rubber raw material is between 120°C and 160°C. The temperature of the cooling medium is preferably not more than 100°C.

A higher temperature gradient can improve heat transfer. If the cooling medium is at its vaporization temperature, the cooling medium can absorb heat during its phase change without its temperature increasing. In this way, the temperature gradient and thus the amount of heat dissipated can be kept almost constant over time.

The heat transfer between the rubber raw material and the cooling medium depends on the thermal conductivity of the raw material, the heat transfer from the raw material to the cooling medium and the thermal conductivity of the cooling medium.

The thermal conductivity of the rubber raw material is usually the limiting factor. If the cooling medium is directly mixed with the rubber raw material so that the cooling medium and the rubber raw material are in direct contact, the heat conduction path from any point within the rubber raw material to the cooling medium is shortened. The heat transfer can thus be increased.

Furthermore, by mixing cooling medium and rubber raw material, the contact area between the two materials is increased, so that the heat transfer between them is improved.

The mixing described thus contributes to increasing the heat transfer. With the same amount of cooling medium, more heat can thus be dissipated or the amount of cooling medium to be used can be reduced. This reduces the cost of the procedure.

The improved cooling makes it possible to introduce more mechanical power into the rubber raw material, which leads to better mixing and thus better material quality of a rubber material made from it. This effect can be achieved, for example, by increasing the speed of an actuator in the mixing chamber. Due to the possible higher speed, the material throughput in the mixing chamber can be increased simultaneously or alternatively. In one embodiment, the speed is between 5 and 50 rpm (revolutions per minute). In another embodiment, the speed exceeds 50 rpm and reaches up to 250 rpm.

Due to the achieved better mixing of the rubber raw material in the mixing chamber, further mixing stages can be saved, which leads to a higher throughput of the entire mixing process. Furthermore, by omitting additional mixing stages, energy can be saved and the efficiency of the process can thus be improved.

The heated and vaporized cooling medium is then discharged from the mixing chamber in gaseous form. In at least one embodiment, the mixing chamber has an opening suitable for this purpose.

In one embodiment, the method comprises the further steps of condensing the cooling medium and returning the cooling medium to the mixing chamber.

After the gaseous cooling medium has been discharged from the mixing chamber, the cooling medium is condensed, for example at ambient temperature. No additional energy input is required for this. In the case of superheated steam, it is first cooled to the evaporation temperature and then condensed. The liquid cooling medium can be further cooled.

In one embodiment, the cooling medium can be cooled to such an extent that it at least partially solidifies to form a solid.

The subsequent return of the cooling medium to the mixing chamber ensures continuous cooling of the rubber raw material. The process of returning the cooling medium to the mixing chamber corresponds to the process of introducing the cooling medium. Due to this circulation of the cooling medium, only a comparatively small amount of cooling medium is required in the entire process. The reuse of the cooling medium continues to save resources and thus contributes to environmental protection.

In at least one embodiment, the cooling medium is injected into the mixing chamber.

For this purpose, an outer wall of the mixing chamber can have an opening in the form of an injection valve or a nozzle.

Injection enables a targeted and metered supply of the cooling medium. Due to the pressure of the cooling medium during injection, the cooling medium is mixed with the rubber raw material directly when it is introduced into the mixing chamber.

In at least one embodiment, the cooling medium is mixed with the rubber raw material by means of a rotor.

The rotor corresponds to the actuator in the mixing chamber, through which mechanical power is introduced to mix the rubber raw material. The rotor allows a simple and effective mixing of the components of the rubber raw material with each other and with the introduced cooling medium. The mixing chamber can include multiple actuators or multiple rotors, so that the location and amount of power introduced can be easily and precisely controlled. For example, the mixing chamber can include two actuators in the form of rotors.

In one embodiment of the method, the cooling medium is introduced only when a temperature that correlates with the temperature of the rubber raw material exceeds a predetermined first temperature threshold. The temperature correlating with the temperature of the rubber raw material is, for example, a maximum allowable temperature of the rubber raw material or a maximum allowable temperature in the mixing chamber. A thermometer is installed in the mixing chamber to check the relevant temperature.

• - Zuführen mehrerer Bestandteile für ein Gummirohmaterial in die Mischkammer. Hierfür ist eine geeignete Zuführvorrichtung in der Außenwand der Mischkammer integriert. Zumindest eines der Bestandteile kann über dieselbe Öffnung bzw. dasselbe Einspritzventil wie das Kühlmedium in die Mischkammer eingeführt werden.
• - Mischen der Bestandteile und Messen einer Temperatur, die mit der Temperatur des Gummirohmaterials korreliert.
• - Zuführen des Kühlmediums, wenn die erste Temperaturschwelle überschritten wird. Während des Zuführens des Kühlmediums wird der Mischvorgang fortgesetzt.
• - Beenden der Zuführung des Kühlmediums, wenn die Temperatur des Gummirohmaterials unter eine zweite Temperaturschwelle gefallen ist, wobei die zweite Temperaturschwelle niedriger als die erste Temperaturschwelle ist. Überschreitet die Temperatur wieder die erste Temperaturschwelle, wird abermals das Kühlmedium zugeführt. Auch nach Beenden der Zuführung des Kühlmittels kann der Mischvorgang fortgesetzt werden.

In one embodiment, the method further includes the following steps:

• - feeding several ingredients for a rubber raw material into the mixing chamber. A suitable feed device is integrated into the outer wall of the mixing chamber for this purpose. At least one of the components can be introduced into the mixing chamber via the same opening or the same injection valve as the cooling medium.
• - Mixing the ingredients and measuring a temperature that correlates with the temperature of the rubber raw material.
• - Supplying the cooling medium when the first temperature threshold is exceeded. The mixing process continues while the cooling medium is being supplied.
• - ending the supply of the cooling medium when the temperature of the rubber raw material has fallen below a second temperature threshold, the second temperature threshold being lower than the first temperature threshold. If the temperature again exceeds the first temperature threshold, the cooling medium is supplied again. The mixing process can be continued even after the coolant supply has ended.

In one embodiment, the speed of the at least one rotor is kept essentially constant. In this way, the same mixing power is continuously introduced into the mixing chamber, so that a high throughput of the mixing process is guaranteed. The cooling method disclosed keeps the temperature during mixing below a critical maximum temperature, which corresponds to the first temperature threshold or is above the first temperature threshold.

In one embodiment, the speed of the at least one rotor is reduced by a maximum of 20% after the first temperature threshold has been reached. This reduces the mixing power introduced into the system and thus also the friction in the mixing chamber that is converted into heat. The mixing chamber or the rubber raw material can thus be cooled more quickly to a desired temperature.

In at least one embodiment, the amount of cooling medium supplied is greater than an amount that can be adsorbed or otherwise accommodated by the gum stock. At least a portion of the coolant can therefore neither be physically nor chemically bound to the rubber raw material or absorbed by it. This subset can be removed from the mixing chamber and thus contributes significantly to the cooling of the mixing chamber through the absorbed heat, which is then withdrawn from the system.

In at least one embodiment, the cooling medium, which is not by adsorption or otherwise bound in the rubber raw material is completely vaporized. After evaporation, the coolant is discharged from the mixing chamber as described. Due to the evaporation, the cooling medium can absorb a significantly higher amount of heat than if no phase change occurs.

The present invention further relates to a mixing apparatus. The mixing apparatus includes a mixing chamber configured for mixing a gum raw material.

A cooling device is integrated in an outer wall of the mixing chamber. The cooling device has at least one opening for supplying a cooling medium, which is solid or liquid but not gaseous, into the mixing chamber.

In one embodiment, the cooling medium is added to the gum raw material outside of the mixing chamber. The rubber raw material and the cooling medium are then fed together into the mixing chamber.

Furthermore, the cooling device has at least one opening for carrying out the cooling medium in the vaporized state from the mixing chamber.

In further embodiments, the cooling device of the mixing chamber has a number of openings for supplying a cooling medium. In this way, the cooling medium can be fed into the mixing chamber more quickly and in a more targeted manner. Feeding in via different openings also enables better distribution of the cooling medium in the mixing chamber.

In one embodiment, the temperature is measured at various locations within the mixing chamber - for example using multiple thermometers. In this way, the temperature can be recorded at different points in the mixing chamber. Areas with higher temperatures can be preferentially cooled by a targeted supply of the cooling medium.

In further embodiments, the cooling device of the mixing chamber has a plurality of openings for carrying out the cooling medium in the vaporized state. In this way, the heat can be dissipated more quickly from the mixing chamber and the entire cooling process, including the supply and discharge of the cooling medium, can be accelerated.

By connecting compressed air or scavenging air to the injection valves, the cooling medium can be discharged even more quickly.

In the mixing apparatus, the gum raw material can be mixed and cooled according to the method previously disclosed.

The cooling medium can be, for example, water or an alternative suitable coolant as described above.

The cooling medium can include several different coolants.

In at least one embodiment, the mixing apparatus is part of a mixing plant. In addition to mixing, further preparatory and post-processing steps are carried out in the mixing plant.

In at least one embodiment, the mixing apparatus includes a second cooling device. The second cooling device includes cooling channels that are integrated into the outer wall of the mixing chamber. A second cooling medium flows through the cooling channels. The second cooling medium can correspond to the first cooling medium.

The outer wall of the mixing chamber is cooled by the integrated cooling channels. The rubber raw material is cooled by heat transfer from the rubber raw material to the cooled outer wall. However, due to poor heat conduction in the rubber raw material, heat is hardly transmitted to the outer wall from the part of the rubber raw material which is not in direct contact with the outer wall.

In at least one embodiment, the mixing chamber includes an actuator through which mechanical power is introduced. The actuator is a rotor, for example. The rotor can also have integrated cooling channels.

In one embodiment, the at least one opening in the outer wall of the mixing chamber is an injection valve.

Other openings in the outer wall may also be injectors or may not be injectors. In further embodiments, the openings can be nozzles.

The at least one injection valve can be used for injecting the cooling medium and for injecting one or more components of the rubber raw material.

Injection enables a targeted and metered supply of the cooling medium. Due to the pressure of the cooling medium during injection, the cooling medium is mixed with the rubber raw material directly when it is introduced into the mixing chamber.

If one injection valve is used both for injecting the cooling medium and components of the rubber raw material, the outlay on equipment in the construction of the mixing chamber is reduced. Further additional injection valves can be saved.

A suitable control device comprising a suitable actuator is required to select the material to be injected. The actuator can be a three-way valve, for example, through which either the cooling medium or a component of the rubber raw material can be admitted into a feed line of the injection valve. In this way it is possible to control when and how much cooling medium is injected into the mixing chamber through the injection valve.

If the rubber raw material does not need to be cooled, the at least one injection valve can be used exclusively for supplying components of the rubber raw material.

If, for example, the temperature in the mixing chamber or the temperature of the rubber raw material is below a temperature threshold specified for this purpose, it is not necessary to supply the cooling medium.

In one embodiment, a thermometer is fitted in the mixing chamber to check the corresponding temperature.

In one embodiment there is at least one second injection valve for injecting one or more ingredients of the gum raw material. In this embodiment, the first injection valve can be set up exclusively for introducing cooling medium.

Two separate injection valves enable the simultaneous supply of cooling medium and one or more components of the rubber raw material. Multiple injection valves can be provided for multiple components of the rubber raw material. One or more injection valves can be set up exclusively for the supply of cooling medium, so that adequate cooling of the rubber raw material is ensured at all times.

Alternatively, in this embodiment, the first injection valve may be configured to both introduce a cooling medium and introduce a component of the rubber raw material.

In further embodiments, the mixing chamber has at least one coolant injection device in its outer wall, which is not an injection valve, and also has at least one vapor outlet device, which can also be integrated into the charging shaft.

In one embodiment, the steam outlet device can also be used to supply or remove other media or components of the rubber raw material.

For the coolant injection device that is not an injection valve, all of the features and properties described in relation to an injection valve in the text above can also apply.

In one embodiment, the openings for supplying or removing the cooling medium are integrated at regular intervals in the outer wall of the mixing chamber. In this way, a uniform supply and removal of the cooling medium into and out of the mixing chamber can be ensured.

In the following, exemplary embodiments of the present invention and comparative examples not according to the invention are explained in detail using exemplary illustrations. The present invention is not limited to the disclosed examples.

• 1a: eine Seitenansicht einer nicht-erfindungsgemäßen ersten Ausführungsform des Mischapparats im Querschnitt,
• 1b: eine Vorderansicht einer nicht-erfindungsgemäßen ersten Ausführungsform des Mischapparats im Querschnitt,
• 2: eine Detailansicht einer Mischkammer mit Kühlungskanälen der ersten Ausführungsform des Mischapparats,
• 3: eine schematische Seitenansicht einer zweiten Kühlvorrichtung einer erfindungsgemäßen zweiten Ausführungsform des Mischapparats im Schnitt,
• 4: ein Temperatur-Zeit-Profil der ersten Ausführungsform des Mischapparats,
• 5: ein Temperatur-Zeit-Profil der zweiten Ausführungsform des Mischapparats.

The illustrations show:

• 1a : a cross-sectional side view of a first embodiment of the mixing apparatus not according to the invention,
• 1b : a cross-sectional front view of a first embodiment of the mixing apparatus not according to the invention,
• 2 : a detailed view of a mixing chamber with cooling channels of the first embodiment of the mixing apparatus,
• 3 : a schematic sectional side view of a second cooling device of a second embodiment of the mixing apparatus according to the invention,
• 4 : a temperature-time profile of the first embodiment of the mixing apparatus,
• 5 : a temperature-time profile of the second embodiment of the mixing apparatus.

In the 1a and 1b an exemplary embodiment of a mixing apparatus 1 not according to the invention is shown. The mixing apparatus 1 has a mixing chamber 2 with a double-cylindrical shape. Various components of a rubber raw material can be fed into the mixing chamber 2 via a feed device 3 , which is also called feed. The feeding device 3 comprises a loading door 3a, via which solid components of the rubber raw material are introduced into a feed chute 3b in the mixing chamber 2. The materials in the feed chute 3b are pushed into the mixing chamber 2 with the aid of a plunger 4 .

Liquid components of the rubber raw material, such as polymer oils, are introduced into the mixing chamber 2 via an injection valve 5 .

The components of the rubber raw material are mixed with the aid of two rotors 6, so that a material is produced in which the individual components are evenly distributed.

Both the rotors 6 and the chamber outer wall 7, which delimits the mixing chamber 2 to the outside, contain cooling channels 8 in the present example.

A detailed view of the mixing chamber 2, in which the cooling channels 8 are shown, offers 2 . A cooling medium such as water flows through the cooling channels 8 . As a result, the surface 6a of the rotors 6 or the inner surface 7a of the chamber outer wall 7 of the cooling chamber 2 is cooled. The rubber raw material is cooled by heat transfer from the rubber raw material to the cooled surfaces 6a and 7a or to the cooling medium.

A typical radius of a cylinder of the double-cylindrical mixing chamber is 900 mm, for example. The two rotors 6 are respectively attached along the central axes of the two cylinders. The distance between a particle of rubber raw material and the cooled surfaces 6a and 7a can be up to 100 mm in this example.

Further cooling of the mixing chamber 2 is therefore necessary primarily because of the low thermal conductivity of the rubber raw material, which makes it difficult for heat to be transferred from the interior of the rubber raw material to the cooled surfaces 6a and 7a.

In a second embodiment according to the invention, a further cooling device is integrated in the disclosed mixing chamber 2, which is detailed in 3 is shown. The second embodiment is essentially the same as the first embodiment, so recurring features will not be described again to avoid repetition.

In the second embodiment, a further cooling medium is injected directly into the mixing chamber 2 by a further injection valve 10 . The additional cooling medium is water in the present example. The water is in the liquid state of aggregation. The further cooling medium can correspond to the first cooling medium in the cooling channels 8 .

By injecting the water is mixed directly with the components of the rubber raw material. The movement of the rotors 6 in the mixing chamber 2 ensures further mixing of the rubber raw material with the cooling medium.

As a result of the mixing that has taken place, the heat conduction paths in the rubber raw material are reduced and the area available for the transfer of heat between the rubber raw material and the cooling medium is increased.

In the present example, the cooling medium water is supplied just below its evaporation temperature of 100°C. By absorbing heat from the rubber raw material, the water evaporates. During evaporation, the water can absorb a large amount of energy in the form of enthalpy of vaporization without increasing the temperature of the water.

The vaporized coolant rises in the mixing chamber 2 . The vaporized cooling medium escapes from the mixing chamber 2 through a vapor outlet device 11, which is arranged in such a way that no liquids reach the outlet device 11. In the present example, the vapor outlet device 11 is arranged in the charging shaft 3b. The steam outlet device can be, for example, an opening in the inlet or a steam outlet valve.

The vaporized cooling medium is condensed outside of the mixing chamber 2 and can then be reintroduced into the mixing chamber 2 via the injection valve 10 . The cooling medium is thus reused in a cooling medium cycle K.

In an exemplary process, the temperature of the gum raw material is to be maintained between 120°C and 160°C during mixing. If the temperature exceeds 160°C, the rubber raw material can no longer be processed with consistent quality. Possible components of the rubber raw material are, for example, natural rubber, carbon in the form of soot, silica and organic polymer compounds.

Two rotors 6 introduce a mixing power into the mixing chamber 2 for thorough mixing. Due to the resulting friction between the rotors 6 and the rubber raw material or within the rubber raw material, part of the energy supplied is converted into heat, which increases the temperature in the mixing chamber 2 .

In 4 the temperature in the mixing chamber 2 is shown as a function of time at a speed of 50 rpm of the two rotors 6 for the first embodiment of the mixing apparatus 1, in which the mixing chamber only has cooling through cooling channels 8. The temperature is measured in the mixing chamber 2 by a thermometer 9 provided for this purpose. Another thermometer 9 can be provided in or at the transition to the feed device 3 .

If the temperature threshold of 160°C is exceeded, the cooling is switched on. The cooling by the cooling channels 8 is not sufficient to dissipate all of the heat supplied. Therefore, in order to avoid a further rise in temperature in the mixing chamber 2, the speed of the rotors 6 must be significantly reduced at the same time. For example, the speed is reduced by 20%. The throughput of the mixing apparatus 1 is thus reduced or the quality of the end product is reduced due to less thorough mixing.

In 5 the same temperature profile is shown as a function of time for a mixing chamber 2 of the second embodiment of the mixing apparatus 1, which comprises both cooling systems. The two cooling systems are, on the one hand, cooling through the cooling channels 8 and, on the other hand, cooling through the direct injection of a cooling medium.

If the temperature in the mixing chamber 2 exceeds a temperature of 160°C in this scenario, the two cooling systems are switched on. Due to the higher possible heat dissipation, the temperature in the mixing chamber 2 can be cooled down again to the desired temperature of 120° C. without reducing the speed. If a temperature below this second temperature threshold of 120° C. is reached in the mixing chamber 2, the cooling is switched off again.

Thus, in the second embodiment, the mixing apparatus 1 can be operated with a consistently high throughput or without reducing the product quality. Due to the more effective cooling, the speed can be increased compared to devices that do not have both cooling systems, and additional mixing stages can be saved. This increases the throughput of the entire process and reduces its costs and energy consumption.

Reference List

1

mixer

2

mixing chamber

3

feeding device

3a

conveyor belt

3b

Intake

4

Rubber stamp

5

Injection valve for rubber raw material

6

rotors

6a

surface of the rotors

7

chamber outer wall

7a

Inner surface of the outer wall of the chamber

8th

cooling channels

9

thermometer

10

Injection valve for cooling medium

11

steam outlet device

K

cooling media cycle

Claims (14)

Process for cooling a rubber raw material in a mixing chamber (2), comprising the following process steps: - introducing the rubber raw material into the mixing chamber (2) and mixing the rubber raw material in the mixing chamber (2), - introducing a cooling medium into the mixing chamber (2), the cooling medium having a solid or a liquid state of aggregation, - simultaneous mixing of the rubber raw material and mixing of the rubber raw material with the cooling medium, - Evaporation of the cooling medium through heat absorption from the rubber raw material, - Carrying out the vaporized cooling medium from the mixing chamber (2). procedure after claim 1 , further comprising the steps of: - condensing the cooling medium, - returning the cooling medium to the mixing chamber (2). procedure after claim 1 or 2 , whereby the cooling medium is injected into the mixing chamber (2). Procedure according to one of Claims 1 until 3 , wherein the cooling medium is mixed with the rubber raw material by means of at least one rotor (6). Procedure according to one of Claims 1 until 4 , wherein the cooling medium is introduced only when a temperature correlating with the temperature of the rubber raw material exceeds a predetermined first temperature threshold. Procedure according to one of Claims 1 until 5 , comprising the steps of: - supplying several components for a rubber raw material, - mixing the components and measuring a temperature which correlates with the temperature of the rubber raw material, - supplying the cooling medium if the first temperature threshold is exceeded, - continuing the mixing, - ending the supplying the cooling medium when the temperature of the rubber raw material has fallen below a second temperature threshold, the second temperature threshold being lower than the first temperature threshold. procedure after claim 6 , wherein the speed of the at least one rotor (6) is kept substantially constant. procedure after claim 6 , wherein the rotational speed of the at least one rotor (6) is reduced by a maximum of 20% after the first temperature threshold has been reached. Procedure according to one of Claims 1 until 8th , characterized in that the amount of cooling medium supplied is greater than an amount that can be adsorbed or otherwise accommodated by the rubber raw material. procedure after claim 9 , characterized in that the cooling medium, which is not bound by adsorption or otherwise in the rubber raw material, is completely vaporized. Mixing apparatus (1) having a mixing chamber (2) which is set up for mixing a rubber raw material, a cooling device being integrated in an outer wall (7) of the mixing chamber (2). - at least one opening for feeding into the mixing chamber (2) a cooling medium (10) which is not gaseous, and furthermore - At least one opening for carrying out the cooling medium (11) in the vaporized state from the mixing chamber (2). Mixing apparatus (1) after claim 11 , wherein the at least one opening for supplying a cooling medium is an injection valve (5, 10). Mixing apparatus (1) after claim 12 , which is set up to use the at least one injection valve (5, 10) for injecting the cooling medium and for injecting one or more components of the rubber raw material. Mixing apparatus (1) after claim 11 or 12 wherein there is at least one second injection valve (5) for injecting one or more components of the rubber raw material.

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