Loading method for a mixing device having a venting system, and mixing device

Abstract

The invention relates to a method for loading a mixing device (10) for a rubber mixture, the mixing device comprising: a mixing chamber (11); a loading shaft (12) for loading the mixing chamber (11), which loading shaft is connected to the mixing chamber (11) via an insertion opening; and a venting system (20) for the loading shaft (12); the method comprising the following steps: - venting the loading shaft (12) by means of the venting system (20); and - adding a mixture component through the loading shaft (12), with the venting system (20) being switched off at a defined point in time.

Description

[0001] Description

[0002] Loading procedure for a mixing device with venting system and mixing device

[0003] The present invention relates to a method for loading a mixing device with a venting system and a mixing device with a venting system.

[0004] In particular, the present invention relates to a mixing device for rubber mixtures and similar materials with an internal mixer, as known, for example, from the documents WO 2022 / 207647 A1 or DE 10 2018 222 073 A1. Such mixing devices generally comprise a feed chute, a mixing chamber, and a base frame with a discharge device.

[0005] In such mixing devices, polymers in bale form, fillers and small chemicals in powder form, and liquid or solid plasticizer oils or waxes are typically mixed. The mixing chamber can be fed, for example, via a flap provided for bales or packaged small chemicals, via a shaft for feeding powders, or via injection nozzles for liquids. Further details are also described, for example, in Limper / Barth / Grajewski: "Technologie der Kautschukverarbeitung" (1989).

[0006] Such mixing devices are generally operated discontinuously or in cycles. A mixing cycle comprises at least one charging or feeding step and one mixing step. Mixing components are thus added to the internal mixer of the mixing device at regular intervals. The goal is to keep the charging period, i.e., the addition of mixing components to the mixing device, as short as possible in order to reduce the cycle time of the mixing device.

[0007] Furthermore, the displacement of air by the mixture components at sometimes high speeds leads to swirling of the mixture components in the mixing device, which can lead to an extension of the feeding time and to contamination, particularly of dead spaces in the mixing device.

[0008] Furthermore, this can also lead to environmental contamination, as the mixing device is not hermetically sealed. This also results in a loss of material from the mixture components, which reduces the efficiency of the process. In conventional mixing processes for rubber production for tire production, approximately 250 kg of raw material are lost per day.

[0009] It is an object of the present invention to at least partially solve the problems described above.

[0010] The present invention relates to a method for loading a mixing device for a rubber mixture comprising a mixing chamber, a charging shaft for charging the mixing chamber, which is connected to the mixing chamber via an inlet opening, and a venting system for the charging shaft, comprising the steps:

[0011] - Venting the feed shaft by extracting air from the feed shaft using the venting system and thus creating negative pressure in the feed shaft and

[0012] - Addition of a mixture component through the feed chute into the mixing chamber, whereby the venting system is switched off at a defined time before or during the addition of the mixture component.

[0013] The point in time at which the venting system is switched off can be defined by an absolute time value, a relative time value, for example a certain time from the addition of a mixture component, or by a technical parameter to be recorded, for example by the values ​​of sensor data to be recorded.

[0014] For a better understanding of the process, a suitable mixing device with possible embodiments will now be described.

[0015] A mixing device for a rubber mixture comprises at least one mixing chamber and a feed chute. The feed chute is suitable for loading the mixing chamber with mixture components.

[0016] The mixing chamber and the feed shaft are connected via an inlet opening. The feed shaft is preferably arranged above the inlet opening of the mixing chamber so that mixture components can be moved from the feed shaft into the mixing chamber by the effect of gravity.

[0017] The mixing device further comprises a venting system for the feed shaft, wherein the venting system is directly connected to the feed shaft. This means that the venting system is directly connected to a shaft wall of the feed shaft. Preferably, the venting system is attached to the shaft wall. The shaft wall can be a side wall of the feed shaft.

[0018] The venting system can be constructed, for example, as a vent line comprising a suitable pipe or hose. The geometric shape of the vent line is not further limited.

[0019] The venting system is suitable for venting an interior of the feed shaft and preferably also of the mixing chamber connected to the feed shaft. In this text, "venting" means the removal of air to create a negative pressure or a vacuum in an interior of the mixing device. Negative pressure refers to a pressure that is significantly below the ambient pressure. For example, a negative pressure is created that is 0.1 bar to 0.3 bar below the ambient pressure. However, the negative pressure created can also be more than 0.3 bar below the ambient pressure.

[0020] The venting system also includes a suction pump. The suction pump is a blower or a vacuum pump for extracting air from the feed shaft. The blower or vacuum pump can be used to create a flow, thus transporting air from the interior of the mixing chamber to enable active venting of the mixing device. The venting process can be started and stopped by switching the blower or pump on or off.

[0021] In addition to the ventilation system, the mixing device also contains a ventilation system which is suitable for extracting mixture components remaining in the feed shaft and mixture components from the environment of the mixing device.

[0022] The ventilation system and the exhaust system are designed to operate at different times. This means that the ventilation system and the exhaust system are two independent systems that can operate at different times. Preferably, the performance of the ventilation system is reduced when the exhaust system is active, i.e., in operation. Alternatively, it is also possible to switch off the ventilation system completely when the exhaust system is in operation.

[0023] The ventilation system is designed to extract mixture components that remain in the feed chute despite the ventilation system's operation. Furthermore, the ventilation system also vents the feed chute even when the ventilation system is not active.

[0024] The venting system and the ventilation system therefore serve different functions and are preferably spatially separated from each other. According to one embodiment, the ventilation system is arranged in the feed shaft above a feed chute, through which the mixture components are fed into the feed shaft, and the venting system is arranged below the feed chute, preferably as close as possible to the mixing chamber.

[0025] Thus, the venting system is suitably positioned to create a negative pressure in the feed chute and mixing chamber until a mixture component is added, which reduces the stirring up of the supplied mixture component. The ventilation system, in turn, is suitably positioned to provide sufficient ventilation of the feed chute even when the venting system is not active, with the aim of minimizing the amount of suction from the mixture components.

[0026] The ventilation system therefore fulfills a central function in a mixing room. It prevents contaminants from entering the room and protects the operator from the dust generated during the mixing process.

[0027] The venting system improves and optimizes the mixer loading process. The material thus reaches the mixing chamber more quickly. By minimizing turbulence, less material is sucked into the ventilation system. Filter dust collected in the venting system is sorted and can be reused.

[0028] Unlike the exhaust system, the ventilation system generally does not allow for the separate extraction and recovery of individual mixture components. However, the ventilation system can essentially be constructed in a similar way to the exhaust system and include similar components.

[0029] The device according to the invention has several advantages.

[0030] On the one hand, by generating the negative pressure or vacuum in the interior of the feed shaft and / or the

[0031] Mixing chamber the air resistance when filling

[0032] Mixing components are lowered into the mixing device. This allows the mixing chamber to be loaded more quickly, accelerating the entire mixing process and increasing the throughput of the mixing device.

[0033] Furthermore, the reduced air resistance reduces or prevents the swirling of the mixture components in the interior. In particular, this prevents or reduces the risk of mixture components settling and accumulating in dead spaces in the interior, for example, and thus contaminating the interior of the mixing device. This also reduces the effort required for maintenance and cleaning of the mixing device.

[0034] Likewise, by suppressing turbulence, little or no mixture components remain in the feed shaft after the filling process or, for example, escape into the environment through unavoidable cracks and gaps in the mixing device. This also prevents mixture components from inadvertently entering the ventilation systems of the feed shaft or the ventilation systems of a room surrounding the mixing device.

[0035] In particular, mixture components that enter the surrounding ventilation systems can hardly be reused, since the corresponding ventilation systems are generally not designed to recover the mixture components and the mixture components are not available separately and therefore cannot be directly reused.

[0036] Furthermore, a previously created vacuum or a previously created negative pressure also suppresses the bridging of mixture components in feed openings and devices such as feed chutes and thus

[0037] Constipation or blockage suppressed or avoided.

[0038] The effects mentioned are particularly advantageous with regard to powdery mixture components, since these are particularly susceptible to turbulence in the air.

[0039] For example, fillers for rubber compounds in the form of solid powders are added to the feed chute.

[0040] According to one embodiment, the venting system of the mixing device further comprises a filter device for separating solid or liquid mixture components from the air, in particular the gaseous air phase.

[0041] The filter device is preferably a filter that occupies the entire cross-section of the vent line. This ensures that any particles or aerosols of a defined structure and size must pass through the filter or remain trapped in the filter.

[0042] This ensures that when the interior is vented, no or only a few mixture components are removed from the mixing device and then, for example, contaminate the ambient atmosphere.

[0043] Preferably, the cross-sectional area of ​​the vent line and the filter device or filter arranged therein can be smaller than in a non-inventive embodiment in which no active venting of the mixing device is provided. Preferably, the mixture components separated by the filter device can subsequently be recovered and reused directly or after a treatment process.

[0044] According to one embodiment, the venting system of the mixing device further comprises a collecting device for collecting the mixture components separated in the filter device. The collecting device can be part of the filter device. For example, the collecting device is a container into which the separated mixture components are deposited in the filter device.

[0045] For this purpose, the filter is shaken, for example when a certain load is reached or at regular intervals, so that the filter cake formed on the filter falls into the container and is collected there.

[0046] In the collecting device, which can also be the filter itself, the mixture components separated by the filter device are preferably collected separately in pure form.

[0047] After completion of a filtering process, the mixture components collected in the collecting device can be recovered and reused.

[0048] According to one embodiment, the feed shaft comprises a feed chute. Mixing components are added to the feed shaft via the feed chute. The feed chute is attached to a shaft wall, for example, a side wall, of the feed shaft. An opening in the shaft wall connects the feed chute to the interior of the feed shaft.

[0049] The feed chute can be designed in the shape of a shaft or a tube, for example.

[0050] For design reasons, the feed chute can be very long, for example, over 5 m or over 6 m. The feed chute is preferably designed so that the mixture components fed through the feed chute are conveyed into the feed shaft by gravity alone.

[0051] Since the feed chute is connected to the interior of the charging shaft, the feed chute, like the charging shaft, can be vented through the venting system, allowing a negative pressure or vacuum to build up inside the feed chute. This reduces air resistance inside the feed chute, increases the conveying speed of the mixture components in the feed chute, and suppresses or prevents the formation of turbulence among the mixture components.

[0052] According to one embodiment, the venting system comprises a valve suitable for stopping an air flow between the venting system and the feed shaft. According to further embodiments, the ventilation system can also have another suitable actuator other than a valve. To stop the air flow, the valve closes the opening between the interior of the feed shaft and the venting system.

[0053] The valve allows the venting process to be started and stopped at any time. Furthermore, closing the valve prevents mixture components from entering the venting system.

[0054] In addition, the venting process can also be started and stopped by switching the pump on and off.

[0055] According to one embodiment, the mixing device comprises several venting systems. The venting can thus be designed more effectively and with greater segregation. For example, different mixture components can be separated using the various venting systems.

[0056] The various ventilation systems can be constructed in a similar or identical manner and are preferably mounted at different locations on the shaft walls of the feed shaft.

[0057] According to one embodiment, the venting systems are suitable for selectively recovering mixture components. For this purpose, the venting systems preferably each have a filter device, which can optionally be specifically adapted to a particular mixture component, e.g., with regard to the filter properties.

[0058] Furthermore, the various venting systems each have a valve or a similar actuator that can be closed to prevent the penetration of mixture components, and in particular of those mixture components for which the respective venting system is not intended, into this same venting system.

[0059] Possible embodiments of the method for loading a mixing device are described below. The mixing device is configured, for example, according to any of the previously described embodiments. Likewise, the previously described mixing devices can have further features that are described in connection with the method.

[0060] In further embodiments, the ventilation system(s) can be arranged separately from the mixing device in the room and can be connected to the mixing device only via appropriate piping. A central ventilation device can also be provided for several mixing devices.

[0061] The process involves several steps.

[0062] In one step, the loading shaft, i.e., the interior of the loading shaft, is vented (venting step). Venting is performed by extracting air from the loading shaft using the venting system. This creates a negative pressure or vacuum in the loading shaft.

[0063] Preferably, the interior of the feed chute is directly connected to the interior of the mixing chamber and the interior of a feed chute, so that during venting, a negative pressure or vacuum can be created in the mixing chamber and the feed chute. In a further step, mixture components are added to the mixing chamber through the feed chute, with the venting system being switched off at a defined time before or during the addition of the mixture component (addition step).

[0064] By previously venting the feed chute, as well as the feed chute and the mixing chamber, the air resistance when feeding the mixture components through the feed chute and, if applicable, the feed chute, is reduced, thus increasing the conveying speed and reducing the occurrence of turbulence. The same applies, if applicable, to the introduction of mixture components into the mixing chamber.

[0065] In one embodiment of the process, the deaeration step and the addition step are carried out at least partially simultaneously. This is particularly necessary when, for example, a static vacuum created only once is not sufficient due to cracks or gaps in the mixing device, but the internal pressure of the mixing device adjusts to the ambient pressure again after the deaeration system is switched off. Another reason for this may be the exchange of air with the environment during the addition of the mixture components.

[0066] According to one embodiment, the method further comprises a step of filtering mixture components from the air in the venting system using a filter device. Preferably, the air is filtered directly during the venting process. For this purpose, the filter device is installed in the venting system as described above.

[0067] The removal of mixture components from the mixing device through the venting system can thus be prevented. Likewise, the escape of mixture components into the ambient air is suppressed. The mixture components are then collected in the filter device and can be reused.

[0068] According to one embodiment of the method, the venting of the feed shaft by means of the venting system is stopped before the addition of the mixture component, or before the mixture component reaches an opening between the feed shaft and the venting system, in order to prevent the mixture components from entering the venting system or to reduce the amount of mixture components entering the venting system.

[0069] The aim is for as large a quantity of mixture components as possible to reach the mixing chamber and be mixed there.

[0070] In particular, according to one embodiment of the method, the venting of the feed shaft is stopped by closing a valve between the feed shaft and the venting system. Venting can thus be stopped quickly, at precisely defined times, and completely, or restarted by opening the valve. Alternatively, the valve can also be closed when or after the venting system pump has been shut down.

[0071] Stopping venting always means, unless explicitly stated otherwise, stopping the venting process by the venting system or systems.

[0072] According to one embodiment of the method, while different mixture components are added one after the other, preferably individually, different venting systems are used to vent the feed shaft.

[0073] The venting systems not used in the respective addition step of a mixture component are simultaneously closed to the feed shaft.

[0074] For venting before, during and / or after the addition of a first mixture component, a first venting system is opened; before, during and / or after the addition of a second mixture component, a second venting system is opened and the first venting system is closed again; before, during and / or after the addition of a further mixture component, a further venting system, a third, fourth venting system, etc., is then opened.

[0075] This ensures that the various mixture components, should suction of the mixture components through the venting not be completely avoided, reach different, appropriate venting systems and can be separated and recovered there.

[0076] According to one embodiment of the process, the various mixture components are separated and collected separately in the respective venting systems so that the mixture components can then be directly reused.

[0077] For this purpose, according to one embodiment of the method, the venting systems can each comprise filter devices for separating the various mixture components.

[0078] According to one embodiment, the method can be designed such that the venting system is switched off as soon as the mixture component reaches the venting system.

[0079] For example, a particle sensor is provided in the feed chute to detect when particles of the mixture component reach the venting system. The sensor can be an optical sensor, for example.

[0080] As soon as the sensor detects that particles are reaching the venting system, the venting system is shut down and preferably closed. The sensor can also be configured or arranged so that the venting system is stopped and / or closed before mixture components reach the venting system. The user can define the number or, for example, particle density at which the sensor triggers the shutdown of the venting system.

[0081] Alternatively or additionally, an opening between the feed chute and the venting system may have a pre-filter which prevents at least some particles of the mixture component from entering the venting system.

[0082] The pre-filter is located upstream of the filter device of the venting system, viewed from the direction of the feed shaft. The pre-filter can preferably be located upstream of a valve for closing the venting system, viewed from the direction of the feed shaft.

[0083] The venting system can be shut down as soon as the negative pressure before and after the pre-filter reaches a defined difference. The corresponding values ​​can be determined by suitable pressure sensors. A difference in the negative pressure before and after the pre-filter means that sufficient air exchange through the pre-filter is no longer possible, causing the pre-filter to become clogged, for example, with mixture components.

[0084] Alternatively or additionally, the venting system can be switched off as soon as the negative pressure value upstream and downstream of the filter device in the venting system has reached a defined difference. The corresponding values ​​can be determined by suitable pressure sensors. A difference in the negative pressure upstream and downstream of the filter device means that sufficient air exchange through the filter device is no longer possible, so that the filter device has become clogged, for example, with mixture components. Preferably, a pressure sensor can be used to measure the pressure upstream of the filter device but downstream of the pre-filter from the direction of the feed shaft.

[0085] According to one embodiment, the mixing device further comprises a supplementary ventilation system for the feed shaft, wherein the performance of the supplementary ventilation system is reduced or wherein the supplementary ventilation system is shut down when the ventilation system is in operation. The ventilation system preferably corresponds to the ventilation system described above with regard to the mixing device.

[0086] The features of the described embodiments of the mixing device and the method are not mutually exclusive and can be combined with one another.

[0087] The invention is described in more detail below with reference to exemplary embodiments and associated figures. The invention is not limited to the exemplary embodiments shown in the figures.

[0088] Similar or apparently identical elements in the figures are designated by the same reference numerals. The figures and their proportions are not necessarily to scale.

[0089] Figure 1 shows a schematic view of a first exemplary embodiment of a mixing device with a mixing chamber, feed chute, and feed chute. Figure 2 shows a detailed side view of the exemplary embodiment of the mixing device in cross-section. The ventilation system on the feed chute is shown.

[0090] Figure 3 schematically illustrates steps of a method for loading and venting a mixing device.

[0091] Figure 4 shows a schematic view of a second embodiment of a mixing device with several venting systems.

[0092] Figure 5 shows a schematic view of an embodiment with sensors.

[0093] Figure 1 shows an exemplary embodiment of a mixing device 10, such as is used for rubber mixtures.

[0094] The mixing device 10 comprises a mixing chamber 11 and a feeding shaft 12.

[0095] The feed chute 12 has a plurality of feed chutes 13 or feed flaps 14. The feed flap 14 has a function analogous to that of the feed chute 13. The feed chute 13 can be replaced by a feed flap 14, or vice versa.

[0096] In the exemplary embodiment, the feed chute 13 is connected to a dispensing device 15. The dispensing device 15 can be designed, for example, as a container scale. The mixture component supplied via the dispensing device 15 can then be weighed and dosed directly in the dispensing device 15. The feed chute 13 can have a high drop height due to its design. An exemplary drop height is more than 5 m and generally less than 10 m.

[0097] The feed flap 14 can also be used to feed mixture components, e.g. for larger rubber bales, polymer bales or small chemicals packaged in plastic film.

[0098] Mainly solid, powdery fillers are added via the feed chute 13.

[0099] Liquid components such as plasticizer oils, on the other hand, are preferably injected directly into the mixing chamber 11, e.g. via nozzles provided for this purpose.

[0100] The mixture components fed into the feed shaft 12 can then be conveyed from the feed shaft 12 into the mixing chamber 11 with the aid of a plunger which is not shown in Figure 1.

[0101] Figure 2 shows a more detailed view of the embodiment of the mixing devices.

[0102] In particular, the mixing chamber 11 with mixing actuators 16 and a base frame 17 for receiving the emptying flap or for receiving the emptying system is also shown here.

[0103] Figure 2 shows a venting system 20 mounted laterally on the feed shaft 12. The venting system 20 can be separated from the feed shaft 12 via a valve 21 or a similar actuator; i.e., an opening between the feed shaft 12 and the venting system 20, through which, for example, air and mixture components can pass from the feed shaft 12 into the venting system 20, is closed.

[0104] The venting system 20 further comprises a venting line leading from the feed shaft 12 to a filter device 22. The filter device 22 enables the separation of solid or liquid mixture components from the air stream in the venting system 20.

[0105] A pre-filter can already be arranged in front of the filter device 22, as seen from the direction of the feed shaft 12, which completely prevents the penetration of mixture components of a certain size into the ventilation system (see Figure 5).

[0106] For this purpose, the filter device 22 preferably comprises a filter that occupies the entire cross-section of the vent line. The vent line is designed, for example, as a pipe, shaft, or hose with any suitable geometry.

[0107] The air flow in the ventilation system 20 or from the feed shaft 12 into the ventilation system 20 is generated, for example, by a blower 23 or a vacuum pump 23. The blower 23 or the vacuum pump 23 is preferably arranged downstream of the filter in the ventilation system 20, as viewed from the direction of the feed shaft 12.

[0108] Using the exemplary embodiment, a method according to the invention with the steps shown in Figure 3 is described below by way of example.

[0109] In step B, mixture components are introduced into the feed shaft 12 via a feed chute 13 or 14.

[0110] In order to ensure that the powdery mixture components are swirled as little as possible during introduction and during falling through the feed chutes, through the feed chute 12 and into the mixing chamber 11, a negative pressure or a vacuum is generated beforehand in step A, at least in the feed chute 12.

[0111] Since the interior of the feed chute 12, the mixing chamber 11 and the feed chute 13 are connected, the negative pressure or vacuum can also be generated in the feed chute 13 and in the mixing chamber 11.

[0112] The negative pressure, i.e. a pressure significantly below the ambient pressure, or the vacuum is created by sucking air from the feed shaft via the ventilation system 20.

[0113] Any mixture components or other solid or liquid foreign matter contained in the air are separated by the filter device 22 in the venting system 20. Before the mixture components are added to the feed chute 12, or at the latest before the mixture components reach an opening between the feed chute 12 and the venting system, the opening to the venting system 20 is closed in step C by closing a valve 21 or a similar actuator. The venting of the mixing device is thus stopped. The vacuum pump or the blower 23 can nevertheless continue to run.

[0114] In an alternative method, closing the actuator is omitted to simplify the process. Alternatively, the vacuum pump or the blower 23 can be switched off.

[0115] Alternatively, the venting is not stopped.

[0116] Due to the negative pressure or vacuum in the feed chute 13, the feed shaft 12, and the mixing chamber 11, the added mixture components can fall freely and are not swirled around, so that the throughput of material fed into the mixing chamber 11 can be increased, contamination by deposits of the mixture components in dead spaces can be prevented, and the efficiency of the mixture, i.e. the proportion of added mixture components that are actually mixed, can be increased. The maintenance and cleaning effort of the mixing device 10 can also be reduced.

[0117] Figure 4 schematically illustrates another exemplary embodiment of the mixing device 10, wherein the mixing device 10 here has a plurality of venting systems 20. Two venting systems 20A and 20B are illustrated by way of example. The detailed explanations from the first exemplary embodiment can also apply to the second exemplary embodiment.

[0118] Starting from a state in which all venting systems 20 are closed towards the feed shaft 12, the first venting system 20A is opened in a first step by opening the valve 21A between the venting system 20A and the feed shaft 12. A negative pressure or vacuum is then created in the feed shaft 12 and the mixing chamber 11.

[0119] Subsequently, the addition of a first mixture component begins. By opening the feed chute 12, the negative pressure in the feed chute 12 can adjust to the ambient conditions again during the addition of the mixture component, which may then necessitate a further venting step using the first venting system 20A during filling. Cracks or gaps in the mixing device 10 may also necessitate a further venting step during or after the addition step. Such a step can also be carried out with respect to the first embodiment or other embodiments and, in particular, does not depend on the precise embodiment.

[0120] During such a step, the first mixture component, e.g., a powdered first filler, may enter the venting system 20A and then be separated and collected by the filter device 22A in the first venting system. After the addition is complete, negative pressure may be restored using the first venting system 20A or the second venting system 20B.

[0121] Subsequently, a second mixture component, for example a second filler, is added. Should it be necessary to restore the negative pressure again during the filling process, the second venting system 20B is used by opening a valve 21B or a similar actuator of the second venting system 20B.

[0122] After the filling process with the second mixture component is completed, the required negative pressure can be restored using the first venting system 20A or the second venting system 20B. If the second mixture component has entered the second venting system 20B, it can be separated and recovered using a filter system 22B.

[0123] Figure 5 shows further details according to embodiments of the mixing device.

[0124] The mixing device 10 can essentially correspond to any of the previously described embodiments and examples. A particle sensor 30 can measure the number or density of the particles of a mixture component present at a specific location. Pressure sensors 31, 32, 33 can measure the pressure of the atmosphere in the feed shaft or between a pre-filter 34 and the filter device 22 or behind the filter device 22. The function of the sensors is as explained in the general part of the description. In the embodiment shown in Figure 5, the venting system 20 further comprises a collecting device 24 for collecting the mixture components separated in the filter device 22. In the example, the collecting device 24 is a container into which the separated mixture components are deposited.

[0125] Furthermore, a supplementary ventilation system 35 is also shown in Figure 5.

[0126] In addition, a further supplementary ventilation system 35 can also be provided in the mixing chamber 11 or preferably, as shown in Figure 5, in a transfer shaft 36 for emptying the mixing chamber 11.

[0127] Reference symbol list

[0128] 10 Mixing device

[0129] 11 Mixing chamber

[0130] 12 Feeding shaft

[0131] 13 Feed chute

[0132] 14 Feed flap

[0133] 15 Dispenser device

[0134] 16 mixing actuators

[0135] 17 Base frame

[0136] 20 Ventilation system

[0137] 20A first venting system

[0138] 20B second ventilation system

[0139] 21 Valve

[0140] 21A first valve

[0141] 21B second valve

[0142] 22 Filter device

[0143] 22A first filter device

[0144] 22B second filter device

[0145] 23 Blower or vacuum pump

[0146] 24 Catch device

[0147] 30 particle sensor

[0148] 31 , 32 , 33 Pressure sensors

[0149] 34 pre-filters

[0150] 35 additional ventilation system

[0151] 36 Transfer shaft

Claims

Patent claims 1. A method for loading a mixing device (10) for a rubber mixture comprising a mixing chamber (11), a charging shaft (12) for charging the mixing chamber (11), which is connected to the mixing chamber (11) via an inlet opening, and a venting system (20) for the charging shaft (12), comprising the steps: Venting the feed shaft (12) by sucking air out of the feed shaft (12) by means of the venting system (20) and thus generating negative pressure in the feed shaft (12) and Addition of a mixture component through the feed shaft (12) into the mixing chamber (11), wherein the venting system (20) is switched off at a defined time before or during the addition of the mixture component.

2. The method according to claim 1, wherein the venting system (20) is switched off as soon as the mixture component reaches the venting system (20).

3. The method according to claim 2, wherein a particle sensor (30) is provided in the feed chute, which detects that particles of the mixture component reach the venting system.

4. The method according to any one of claims 1 to 3, wherein an opening between the feed chute (12) and the venting system (20) has a pre-filter (34) which prevents at least some particles of the mixture component from entering the venting system (20).

5. The method according to claim 4, wherein the venting system (20) is switched off as soon as the value of the negative pressure before and after the pre-filter (34) has reached a defined difference.

6. The method according to any one of claims 1 to 5, further comprising a step of Filtering mixture components from the air by means of a filter device (22) in the ventilation system (20).

7. The method according to claim 6, wherein the venting system (20) is switched off as soon as the value of the negative pressure before and after the filter device (22) in the venting system (20) has reached a defined difference.

8. The method according to any one of claims 1 to 7, wherein the mixing device (10) comprises a supplementary ventilation system (35) for the feed shaft (12), wherein the performance of the supplementary ventilation system (35) is reduced or wherein the supplementary ventilation system (35) is switched off when the ventilation system (20) is in operation.

9. The method according to any one of claims 1 to 8, wherein the venting system (20) is switched off before the mixture component reaches an opening between the feed chute (12) and the venting system (20).

10. Method according to one of claims 1 to 9, wherein when the venting system (20) is switched off, a valve (21) between the feed shaft (12) and the venting system (20) is closed.

11. Method according to one of claims 1 to 10, wherein during the addition of different mixture components, different venting systems (20) are used successively to vent the feed shaft (12) and the venting systems (20) not used in the respective addition step are closed to the feed shaft (12).

12. The method according to claim 11, wherein the various mixture components in the respective venting systems (20) must be separated and collected separately.

13. Mixing device (10) for a rubber mixture comprising a mixing chamber (11), a charging shaft (12) for charging the mixing chamber (11), which is connected to the Mixing chamber (11) is connected via an inlet opening, a ventilation system which is suitable for sucking off mixture components remaining in the feed layer, and a ventilation system (20) for the feed shaft (12), wherein the ventilation system (20) is directly connected to the feed shaft (12), wherein the ventilation system (20) comprises a suction pump (23) for sucking air out of the feed shaft (12), wherein the ventilation system and the ventilation system (20) are intended to be in operation at different times.

14. Mixing device (10) according to claim 13, wherein the venting system (20) comprises a filter device (22) for separating solid or liquid mixture components.

15. Mixing device (10) according to one of claims 13 to 14, wherein the venting system (20) comprises a collecting device (24) for collecting the separated mixture components.

16. Mixing device (10) according to one of claims 13 to 15, wherein the feed shaft (12) comprises a feed chute (13, 14) which is suitable for adding mixture components into the feed shaft (12).

17. Mixing device (10) according to claim 16, wherein the venting system (20) is arranged in the feed shaft (12) below the feed chute (14) and the ventilation system (35) is arranged in the feed shaft (12) above the feed chute (14).

18. Mixing device (10) according to one of claims 13 to 17, wherein the mixing device (10) comprises a plurality of venting systems (20).

19. Mixing device (10) according to claim 18, wherein the venting systems (20) are suitable for selectively recovering mixture components.

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