Metering devices for bulk materials, system comprising such a metering device and method for cleaning a metering device

Abstract

Metering device (1) for bulk material, the device comprising at least - a receiving unit (3) for receiving bulk material to be dosed and - a discharge area (13) which follows the receiving unit (3) in the main conveying direction - - in which bulk material, in particular via a bulk material discharge opening (11) of the receiving unit (3), can be displaced from the receiving unit (3), and - a discharge element (15) provided within the discharge area (13) for discharging the bulk material from the discharge area (13) towards a discharge opening (17) of the device, - a first nozzle (29) for at least temporarily ejecting a fluid jet (31) into the receiving unit (3), - - wherein the first nozzle (29) is oriented such that an inner surface (25) of the receiving unit (3) can be exposed at least partially to the fluid jet (31) in order to form a fluid flow in the form of a cyclone as a cleaning fluid flow at least partially within the receiving unit (3) and characterized in that a second nozzle (45, 39) is provided for blowing fluid into a coupling area (47) in which coupling area (47) the discharge element (15) is connected to a drive element (49), such as a drive shaft.

Description

field of technology

[0001] The present invention relates to metering devices for bulk material, a system comprising such a metering device, a closure means, a bearing element, uses and methods for cleaning a metering device. State of the art

[0002] Metering devices for dispensing bulk materials are known from the prior art. In these devices, the bulk material to be metered flows from a receiving unit, such as a container, into a discharge area following the receiving unit in the main conveying direction. From there, the bulk material to be metered is discharged from the device in a defined quantity by means of a discharge element. Typically, cleaning of the device is necessary, especially when changing the type of bulk material, to prevent cross-contamination.

[0003] Patent 10 2013 100 812 A1, for example, discloses an extrusion device in which different cleaning units are arranged for cleaning the feed tanks. In addition to a knocking unit arranged on a downpipe to exert a mechanical influence on the downpipe in the form of vibration or knocking, a blow-off system is provided in the tank wall. This system can generate a burst of compressed air or a cyclone-like vortex, which enables cleaning of the feed tank.

[0004] From DE 10 2013 006 822 A1, a cleaning arrangement for a material storage container is also known, in which compressed air is supplied to the container via a nozzle device. The cleaning arrangement has rotatably arranged nozzles that can be set into rotation by the exiting airflow.

[0005] From JP 2022 092 114 A a cleaning device for a material container is known in which a cleaning granulate can be added to the supplied airflow.

[0006] Furthermore, DE 20 2015 105 482 U1 discloses a metering device with a cleaning device in which ionized air is used to form a cyclone vortex within a filling hopper and to blow out a conveying housing of a screw conveyor.

[0007] Finally, DE 10 2011 112 016 B3 also shows a metering device with a cleaning device that has nozzles arranged in the storage container. The cleaning process is controlled by a number of shut-off valves that allow the flow of the cleaning gas through the interior of the metering device and to the screw conveyor.

[0008] However, cleaning such a dosing device and its components is time-consuming and expensive. Therefore, cleaning is performed as infrequently as possible, and frequent changes in the type of bulk material are avoided to prevent cross-contamination. This, however, can impair the device's performance and make it more difficult to achieve maximum utilization. Summary of the invention

[0009] It is therefore an object of the present invention to overcome the described disadvantages of the prior art and in particular to provide means that make it possible to carry out efficient and economical cleaning of a dosing device for dosing bulk material.

[0010] The problem is solved by the invention with a device according to claim 1, a system according to claim 10 and a method according to claim 11.

[0011] For this purpose, a metering device for bulk material is proposed, the device comprising at least one receiving unit for receiving bulk material to be metered and at least one first nozzle for at least temporarily ejecting a fluid jet into the receiving unit, wherein the first nozzle is oriented such that an inner surface of the receiving unit can be exposed to the fluid jet at least in certain areas, in order to form a fluid flow in the manner of a cyclone as a cleaning fluid flow, in particular at least within the receiving unit and / or at least in certain areas.

[0012] The invention is based on the surprising finding that settled and / or adhering residues of bulk material can be reliably and easily detached from parts of the metering device that come into contact with the bulk material and transported away in the main conveying direction, aided by a fluid flow formed within the receiving unit. By forming this fluid flow, referred to as the cleaning fluid flow, in the manner of a cyclone, at least within the receiving unit, a surprisingly high efficiency can be achieved in cleaning the metering device and its components. This allows the cleaning time to be advantageously reduced and / or the device to be cleaned of larger quantities of settled and / or adhering bulk material in the same or even less time.

[0013] Above all, the inventors recognized that the proposed cleaning concept can be implemented without manual intervention. This allows cleaning to be carried out automatically and programmatically when needed. As a result, not only are flexible cleaning cycles possible, but the conventionally high costs and long downtimes associated with cleaning dosing devices can also be significantly reduced.

[0014] Above all, thanks to the proposed concept, the dosing device no longer needs to be opened by a cleaning person and even manually cleared of settled and / or adhering bulk material. This allows for the safe cleaning of dosing devices used to dispense hazardous bulk materials. This, in turn, increases occupational safety for the personnel involved. Furthermore, no additional or less stringent safety requirements are associated with the cleaning process, as no personnel need to be protected from contact with the bulk material during cleaning. All these advantages significantly reduce the maintenance and operating costs of the dosing device.

[0015] In an advantageous embodiment, the metering device has at least two or more than two first nozzles, each for at least temporarily ejecting a fluid jet into the receiving unit, wherein each first nozzle is advantageously oriented such that each of several areas of the inner surface of the receiving unit can be exposed, at least partially, to the respective fluid jet, in order to form, at least partially within the receiving unit, a fluid flow of the type of a cyclone as a cleaning fluid flow. For each nozzle, one of the options mentioned in this application can then be advantageously provided individually.

[0016] When the present application refers to the cleaning fluid flow as being “of the type of a cyclone”, it preferably means that (a) the cleaning fluid flow (i) is a vortex flow, in particular a three-dimensional and / or turbulent flow, and / or (ii) performs a rotational movement about a central axis of the receiving unit, and / or (b) that, due to the centripetal force, separated fluid components, in particular denser fluid components such as cleaning granules, move along, and in particular in contact with, the inside of the receiving unit, which preferably increases the cleaning effect.

[0017] For example, it can be visually checked, especially using a wick test, whether a fluid flow is formed in the manner of a cyclone.

[0018] The person skilled in the art understands that preferably in areas where the fluid flow is not formed in the manner of a cyclone, the fluid flow is not referred to as a cleaning fluid flow, notwithstanding the fact that a cleaning effect may be observable in these places as well.

[0019] The invention thus takes advantage of the fact that residues of bulk material located on the inner surface of the receiving unit can be detached particularly reliably (at least largely) by a vortex flow. The detached bulk material residues can then be discharged from the device. For example, they can be removed from the device by applying a vacuum and suctioning out the detached bulk material residues.

[0020] This allows for a quick changeover of the bulk material type, thereby improving the utilization of the dosing system. In particular, cross-contamination can be avoided or at least significantly reduced. Electrostatically charged residues of bulk material can also be effectively removed using the proposed concept.

[0021] The device is designed to form the fluid flow as a cleaning fluid flow in the manner of a cyclone and / or when the fluid jet is ejected or can be ejected from the first nozzle in such a way that the fluid jet interacts with the receiving unit or parts thereof (such as the inner surface of the receiving unit) to form the cleaning fluid flow.

[0022] In an advantageous embodiment, the fluid is ejected from the first nozzle for a period of 1 second or longer, preferably 10 seconds or longer, preferably 30 seconds or longer, preferably 60 seconds or longer, and / or 100 seconds or less, preferably 60 seconds or less. Optionally, the first nozzle is configured for a correspondingly long fluid ejection time.

[0023] Preferably, the bulk material to be dosed is a powdery, granular or lumpy mixture that is or can be in a pourable form.

[0024] Examples of advantageous bulk materials include rock, building materials, in particular topsoil, sand, gravel and / or cement, raw materials, in particular ore, coal, clay and / or road salt, foodstuffs, in particular cereals, sugar, salt, coffee and / or flour, and / or powdered goods, in particular pigments, fillers, granules and / or pellets.

[0025] The fluid of the fluid jet ejected from the first nozzle can be, for example, an alcohol, water, a gas, in particular an inert gas or hydrogen, or a gas mixture, such as air, in particular compressed air.

[0026] The fluid can advantageously be ejected from the first nozzle at an absolute pressure of more than 5 bar, preferably more than 10 bar, preferably more than 20 bar.

[0027] Alternatively or additionally, the device may also be configured so that a fluid jet ejected from the first nozzle into the receiving unit interacts with, in particular at least areas of, the inner surface of the receiving unit in such a way that a fluid flow of the type of a cyclone is formed as a cleaning fluid flow, in particular at least partially within the receiving unit, and / or wherein the cleaning fluid flow within the receiving unit is formed along a flow path, in particular the device is configured or can be configured for this purpose, wherein preferably the flow path runs at least partially and / or at least partially along a spiral path, in particular with a decreasing diameter, and / or from top to bottom with respect to the direction of gravity.

[0028] By decreasing the diameter of the spiral path, the speed of the fluid flow can be increased. This allows for a high cleaning effect even in more distant areas.

[0029] Alternatively or additionally, it can also be provided that the receiving unit has a bulk material feed opening for feeding bulk material into the receiving unit and / or a bulk material discharge opening for discharging bulk material from the receiving unit and preferably bulk material can be fed into the receiving unit via the bulk material feed opening and / or bulk material can be displaced from the receiving unit towards a discharge opening of the device via the bulk material discharge opening.

[0030] The main conveying direction advantageously runs from the receiving unit towards the bulk material discharge opening.

[0031] Alternatively or additionally, it can also be provided that the receiving unit has a lid, in particular a removable one, and preferably the bulk material feed opening is provided in the lid.

[0032] The lid securely closes the receiving unit. A bulk material feed opening in the lid ensures safe operation of the dosing device, as the interior of the receiving unit cannot be accidentally touched during dosing and / or cleaning. For example, the lid can be easily removed for maintenance work, providing better access to the interior of the receiving unit.

[0033] Alternatively or additionally, it may also be provided that the bulk material discharge opening is opposite the bulk material feed opening and / or that the bulk material discharge opening is located below the first nozzle and / or the bulk material feed opening in the direction of gravity.

[0034] For example, the bulk material feed opening and the bulk material discharge opening share a common central axis. Alternatively, the central axes of the bulk material feed opening and the bulk material discharge opening can be different and preferably run parallel or inclined to each other.

[0035] Alternatively or additionally, it may also be provided that the recording unit is designed to be rotationally symmetrical, especially at least in certain areas.

[0036] This makes the recording unit particularly easy to use. And it allows for the particularly advantageous creation of a cyclone-like flow.

[0037] Alternatively or additionally, it may also be provided that the receiving unit has or represents a container and / or, in particular at least partially, such as an inner part of the receiving unit, is designed in a truncated cone shape.

[0038] Alternatively or additionally, it can also be provided that the inner surface of the receiving unit is in contact with the bulk material at least temporarily during the dosing operation of the device and / or can be brought into contact with it and / or wherein the inner surface is formed at least partially in the form of a lateral surface of a truncated cone.

[0039] Alternatively or additionally, it may also be provided that the receiving unit has at least a section with a diameter, in particular an inner diameter, that tapers along the direction of gravity.

[0040] By having a hollow, truncated cone shape and / or a decreasing diameter, a pronounced vortex flow can be formed within the receiving unit particularly efficiently and reliably, and the spiral flow of the fluid flow already mentioned above can be achieved.

[0041] Alternatively or additionally, it can also be provided that the first nozzle is aligned in such a way, in particular relative to the receiving unit, preferably to the inner surface of the receiving unit, that the fluid jet ejected from the first nozzle can be deflected by means of an impact area of ​​the inner surface of the receiving unit.

[0042] In other words, the first nozzle is aligned with this impact area. The fluid striking it is then deflected by the inner surface of the receiving unit. For example, the impacting fluid follows the inner surface and is thereby forced into a curved motion, particularly a circular motion, according to the shape of the inner surface. With a suitable shape of the inner surface (such as the truncated cone shape discussed above or a decreasing diameter), the fluid then flows spirally downwards along the circular path.

[0043] The deflection can advantageously take place at least partially along a curvature direction of the inner surface, which curvature direction corresponds to a rotation direction of the receiving unit.

[0044] Alternatively or additionally, it can also be provided that the inner surface has a curved profile at least in certain areas, preferably everywhere, along at least one circumferential direction of the receiving unit, and preferably the profile of the impact area is determined, in particular completely or at least partially, by the curved profile.

[0045] This makes it particularly reliable to force the impacting fluid, at least in sections, onto a curved path, especially a circular path and / or spiral path, and to form a flow similar to that of a cyclone.

[0046] Alternatively or additionally, it can also be provided that the first nozzle is oriented in such a way, in particular relative to the receiving unit, preferably to the inner surface of the receiving unit, that the fluid jet ejected from the first nozzle has a tangential, horizontally extending first velocity component at the point of impact on the inner surface, in particular at the impact area, and in particular the first velocity component is greater than a second velocity component of the fluid jet ejected from the first nozzle that is parallel to the direction of gravity.

[0047] In other words, the first nozzle is advantageously angled towards the impact area and / or the inner surface of the receiving unit. In particular, it may be desirable for the fluid to be directed from the first nozzle not frontally, but obliquely onto the impact area.

[0048] The formation of a cyclone-like formation can thus be advantageously achieved through the interaction between the first nozzle, in particular its position and orientation, and the receiving unit, in particular the inner surface of the receiving unit.

[0049] Alternatively or additionally, it can also be provided that the first nozzle has a fluid output of 500 m³ / h. 3 / h up to 5000 m 3 / h, especially from 1000 m 3 / h up to 3000 m 3 / h, is operable and / or the device for operating the first nozzle with such a fluid output is set up.

[0050] This allows for a particularly beneficial cleaning effect.

[0051] Alternatively or additionally, it may also be provided that the fluid jet can be ejected from the nozzle at a speed of more than 0.1 m / s, in particular more than 1 m / s, and / or less than 100 m / s, in particular less than 10 m / s, and / or that the device is set up to operate the first nozzle with such a fluid ejection.

[0052] Alternatively or additionally, it may also be provided that the nozzle has a distance from the inner surface in the direction of radiation of more than 0.1 cm, in particular more than 1 cm, and / or of less than 10 cm, in particular less than 5 cm.

[0053] Alternatively or additionally, it may also be provided that the first nozzle, in particular at least during the dosing and / or cleaning operation of the device, protrudes at least partially and / or at least temporarily into the receiving unit.

[0054] This ensures that the fluid can be safely introduced into the receiving unit.

[0055] Alternatively or additionally, it may also be provided that the first nozzle is arranged on the lid of the receiving unit, in particular in such a way that, when the lid is closed, the first nozzle protrudes at least partially into the receiving unit.

[0056] This makes existing dosing devices particularly economical and easy to retrofit, as only the lid needs to be fitted with a suitable first nozzle. Because the first nozzle is integrated into the lid, the necessary modifications to existing dosing devices are limited to a few, easily retrofitted parts.

[0057] Alternatively or additionally, it may also be provided that the first nozzle is arranged on the inner surface of the receiving unit, in particular such that the first nozzle protrudes at least partially into the receiving unit.

[0058] This allows the first nozzle to be securely and stationary attached to the receiving unit.

[0059] Alternatively or additionally, it may also be provided that the first nozzle, in particular at least during the dosing and / or cleaning operation of the device, is arranged in the receiving unit in such a way that it is positioned above a defined level, in particular relative to a maximum permissible fill level of bulk material in the receiving unit during the dosing operation of the dosing device.

[0060] This is particularly advantageous because it prevents or at least significantly reduces contamination of the first nozzle with bulk material during the metering operation of the device. This eliminates the need for manual cleaning of the first nozzle itself, or at least minimizes it. As a result, metering operation of the device is possible without lengthy interruptions for nozzle cleaning, which can be especially economical.

[0061] For example, an optional self-cleaning function can be provided for the first nozzle. This ensures that any remaining bulk material can be reliably removed from the first nozzle as well.

[0062] Alternatively or additionally, it can also be provided that the first nozzle is movable back and forth between a cleaning position and a rest position, wherein preferably the first nozzle in the cleaning position, in particular in the direction of gravity, projects further into the receiving unit than in the rest position and / or the first nozzle in the rest position is at least partially retractable into a cavity and / or a housing recess of the receiving unit.

[0063] This allows the first nozzle, for example, to remain in a rest position during the dosing operation of the device. As a result, it does not interfere with the dosing process and also occupies little or no space within the receiving unit, thus allowing more bulk material to be stored in the receiving unit. Furthermore, this design minimizes or completely prevents the first nozzle from being affected by the bulk material.

[0064] Alternatively or additionally, it can also be provided that residues of the bulk material can be removed from the inner surface of the receiving unit by the cleaning fluid flow and / or that residues of the bulk material removed from the inner surface of the receiving unit can be transported in the direction of the bulk material discharge opening and / or the discharge opening.

[0065] This makes it particularly easy and reliable to remove the bulk material residue from the device.

[0066] Alternatively or additionally, the device may also be provided for in that it has a reservoir for receiving a cleaning agent, in particular a granular cleaning agent, such as cleaning granules, and / or is connected or connectable to such a reservoir.

[0067] The use of a cleaning agent can further enhance the cleaning effect of the cleaning fluid flow and improve the cleaning result. Therefore, it is advantageous if the device has a suitable reservoir.

[0068] For example, a cleaning agent, particularly a low-elastic, organic and / or inorganic granulate, such as one consisting of or containing granules made of polyethylene and / or polypropylene, can be used. Materials that are processed elsewhere in the process and are therefore readily available are particularly advantageous as cleaning agents.

[0069] Alternatively or additionally, it may also be provided that the device, in particular in the lid of the receiving unit, has a cleaning agent supply opening for supplying the cleaning agent, in particular from the storage container, into the interior of the receiving unit.

[0070] This allows the cleaning agent to be fed to the dosing device with particular reliability. For example, the cleaning agent can be fed from the reservoir into the interior of the receiving unit via a connecting hose that opens into or passes through the cleaning agent feed opening.

[0071] Alternatively or additionally, it may also be provided that the first nozzle and / or the cleaning agent supply opening is or are arranged offset from a defined or definable vertical center plane of the receiving unit.

[0072] This allows the first nozzle to be positioned particularly close to the inner surface / impact area. In this way, the cleaning fluid flow can be generated with exceptional reliability.

[0073] The middle plane can, for example, have a vertical central axis of the recording unit.

[0074] It goes without saying that the middle level can be a purely conceptual construct and does not necessarily have to be present as a physical characteristic.

[0075] Alternatively or additionally, the device may also be designed to supply the cleaning agent, in particular from the storage container and / or via the bulk material feed opening and / or the cleaning agent feed opening, to the fluid flow, preferably after the cleaning fluid flow has stabilized in the manner of a cyclone.

[0076] Specifically, the cleaning agent is only added after the fluid has begun flowing into the intake unit. This two-stage process ensures reliable flow formation and allows for the initial removal of easily removable bulk material residues before the remaining residues are removed by the cleaning agent.

[0077] Alternatively or additionally, the device may also be designed to supply the cleaning agent to the ejected fluid jet and / or the cleaning fluid flow, which is preferably capable of being carried along with the cleaning fluid flow at least temporarily and / or at least section by section.

[0078] In the first option, the cleaning agent is added to the fluid ejected by the first nozzle. This allows for a particularly compact device design, as no additional openings are needed to supply the cleaning agent to the receiving unit. The cleaning agent can be permanently or at least temporarily mixed with the fluid being ejected as a jet. For example, the cleaning agent can be added to the fluid with a time delay, enabling a two-stage process as described above.

[0079] Alternatively or additionally, it may also be provided that the cleaning agent can be supplied via a separate opening and / or via the same opening as the bulk material of the receiving unit.

[0080] Alternatively or additionally, it may also be provided that the lid of the receiving unit has the cleaning agent supply opening.

[0081] The device has at least one discharge area that follows the receiving unit in the main conveying direction and / or can be displaced from the receiving unit into the bulk material, in particular via the bulk material discharge opening of the receiving unit, and a discharge element provided within the discharge area for discharging the bulk material from the discharge area towards a discharge opening of the device. A second nozzle is provided for injecting fluid into a coupling area, in which coupling area the discharge element is connected to a drive element, such as a drive shaft, wherein bulk material accumulated within the coupling area is preferably not displaceable by the discharge element.

[0082] Preferably, at least one further, third nozzle is provided for blowing fluid into at least one area surrounding the discharge element.

[0083] This is based on the surprising finding that even hard-to-reach areas of the dosing device can be cleaned of bulk material residue by blowing in a fluid using additional (second and / or third) nozzles, thereby loosening the stuck bulk material.

[0084] This makes the cleaning process particularly efficient and cost-effective. Disassembling the dosing device to clean hard-to-reach areas is therefore no longer necessary.

[0085] It was discovered, surprisingly, that the discharge element can remain advantageously installed during cleaning and be used to swirl the fluid flow introduced by the second nozzle. Thus, the cleaning effect can be significantly enhanced, quite unexpectedly, by the presence of the discharge element.

[0086] In other words, it can be advantageously generated that a fluid swirl can be created around the discharge element. For this purpose, the discharge element is advantageously a spiral or a screw, or otherwise has a surface that is suitable or designed to create turbulence in a fluid guided along its surface.

[0087] The coupling area can be a separate and / or at least partially isolated section from the discharge area. Even in this case, cleaning with the proposed third nozzle is efficient, particularly simple, and thorough. The proposed solution is especially suitable for efficient and thorough cleaning if any bulk material lodged in the coupling area cannot be discharged through the discharge element.

[0088] The coupling area can be part of a bearing element for supporting the discharge element.

[0089] Furthermore, impairments to the discharge element, especially in the coupling area, caused by compacted bulk material can be avoided or at least reduced by providing one or more of the proposed first and second nozzles.

[0090] Furthermore, it was discovered that using the first nozzle together with the second and / or third nozzle leads to surprising synergies. The combined use of the respective nozzles resulted in a cleaning performance that surpasses that achievable with the sequential use of the individual nozzles.

[0091] In one embodiment, it can also be advantageous for the device to be configured to actuate the discharge element, in particular to rotate it, at least temporarily during the emission of a fluid jet via the first nozzle. In this way, an advantageous cleaning effect was also observed with regard to the receiving unit alone.

[0092] In an advantageous embodiment, the fluid is ejected from the second nozzle for a period of 1 second or longer, preferably 10 seconds or longer, preferably 30 seconds or longer, preferably 60 seconds or longer, and / or 100 seconds or less, preferably 60 seconds or less. Optionally, the second nozzle is configured for a correspondingly long fluid ejection time.

[0093] In an advantageous embodiment, the fluid is ejected from the third nozzle for a period of 1 second or longer, preferably 10 seconds or longer, preferably 30 seconds or longer, preferably 60 seconds or longer, and / or 100 seconds or less, preferably 60 seconds or less. Optionally, the third nozzle is configured for a correspondingly long fluid ejection period.

[0094] The fluid that can be injected through the second nozzle can be, for example, an alcohol, water, a gas, in particular an inert gas or hydrogen, or a gas mixture, such as air, in particular compressed air.

[0095] The fluid that can be injected through the third nozzle can be, for example, an alcohol, water, a gas, in particular an inert gas or hydrogen, or a gas mixture, such as air, in particular compressed air.

[0096] The fluid that can be injected through the second nozzle can be used to stir up and / or remove bulk material residues in an area around the discharge element.

[0097] The fluid that can be injected through the third nozzle can be used to stir up and / or remove bulk material residues in a coupling area.

[0098] The invention proposes a metering device for bulk materials, wherein the device has at least one receiving unit for receiving bulk material to be metered, wherein the device has at least one discharge area which follows the receiving unit in the main conveying direction and / or is displaceable from the receiving unit into the bulk material, in particular via the bulk material discharge opening of the receiving unit, and a discharge element provided within the discharge area for discharging the bulk material from the discharge area towards a discharge opening of the device, wherein preferably (i) at least one second nozzle is provided for injecting fluid into at least one area surrounding the discharge element and / or (ii) at least one third nozzle is provided for injecting fluid into a coupling area in which the discharge element is connected to a drive element, such as a drive shaft.wherein preferably bulk material accumulated within the coupling area cannot be displaced by the discharge element.

[0099] The previously stated advantages and surprising effects of these features apply accordingly. The aforementioned options can also be provided individually or in any combination, unless the context indicates otherwise.

[0100] This is particularly advantageous because the dead space, i.e. the space in the direction of gravity below the discharge element, was conventionally hardly accessible without removing the discharge element and therefore difficult to clean.

[0101] By allowing fluid to be blown into the dead space, existing bulk material can be loosened and / or removed by blowing it out or stirring it up.

[0102] Therefore, removing the discharge element is not necessary for reliable cleaning of the dead space.

[0103] Preferably, the bearing element includes the coupling area. That is, the coupling area is advantageously part of the bearing element.

[0104] Alternatively or additionally, the invention may also provide that the discharge element is arranged to float within the discharge area.

[0105] Alternatively or additionally, the invention may also provide that the discharge element comprises or represents a screw, a trough, a screw, a spiral, a clearing arm, a sluice wheel, a rotary valve, a rotary valve, a sluice and / or a roller.

[0106] Alternatively or additionally, the invention may also provide that the length of the discharge element along its main extension direction is from 0.1 m to 2 m, in particular from 0.1 m to 1 m.

[0107] Alternatively or additionally, the invention may also provide that the maximum outer diameter of the discharge element perpendicular to its main extension direction is from 0.5 cm to 50 cm, in particular from 0.5 cm to 10 cm.

[0108] Alternatively or additionally, the invention may also provide that the fluid can be ejected with the second nozzle along a direction perpendicular to the main extension direction of the discharge element and / or that the second nozzle is arranged on or in the bearing element.

[0109] For example, the fluid can be ejected radially towards the discharge element via the second nozzle.

[0110] Alternatively or additionally, the invention may also provide that the further nozzle for blowing fluid into a dead space in the direction of gravity is provided below the discharge element and / or the second nozzle is arranged on or in a bearing element for supporting the discharge element.

[0111] Alternatively or additionally, the invention may also provide that at least two further nozzles are provided with which fluid can be blown into the area around the discharge element, in particular into the dead space, in two opposite directions, wherein preferably at least one of the further nozzles is provided at each of the two ends of the discharge area.

[0112] This makes it particularly advantageous to clean even a large discharge area.

[0113] Alternatively or additionally, the invention may also provide that the fluid can be ejected with the further nozzle along a direction perpendicular to the direction of gravity and / or parallel or antiparallel to the main extension direction of the discharge element.

[0114] It was surprisingly discovered that the discharge element contributes to a favorable turbulence of the fluid ejected from the further nozzle, especially when the fluid is released from the further nozzle along the main extension direction of the discharge element (or antiparallel to it).

[0115] Alternatively or additionally, the invention may also provide that the discharge opening opens into a discharge element, in particular having a nozzle, a vertical discharge and / or a downpipe, wherein preferably bulk material can be discharged from the metering device via the discharge element in a direction parallel or inclined, in particular at an angle of less than 90°, to the direction of gravity.

[0116] The discharge element allows the bulk material metered by the dosing device to be reliably fed into a subsequent process. For example, the bulk material can be fed to an extruder in a metered manner.

[0117] Similarly, the cleaning agent can also be reliably discharged from the dosing device via the discharge element.

[0118] Alternatively or additionally, the invention may also provide that the discharge element has a suction opening for extracting a fine fraction, in particular dust, and / or that the suction opening and / or the discharge opening is or can be connected to a suction device for extracting dust.

[0119] In this way, a surprisingly simple yet reliable way was created to target fine particles, such as bulk material residues, with the cleaning agent during the cleaning process.

[0120] For example, if the cleaning agent is granular, during the cleaning process the cleaning agent can be guided through the discharge element and downwards along the direction of gravity, and dust particles and / or powdery bulk material residues can be at least partially extracted from the dosing device via the extraction opening.

[0121] Alternatively or additionally, the invention may also provide that the extraction opening points upwards against the direction of gravity.

[0122] This ensures, in a particularly simple yet reliable manner, that no or as little cleaning agent as possible, especially in granular form, reaches the extraction unit during cleaning.

[0123] Alternatively or additionally, the invention may also provide that the dosing device is a differential dosing device, such as a differential dosing scale.

[0124] The operating principle of a differential dosing scale is generally known to those skilled in the art. Advantageously, the differential dosing scale has at least one weight sensor, such as at least one load cell, so that the weight of a weighed system can be determined at different times. Based on the weight difference between two consecutive times, the quantity of bulk material discharged can be determined. This value, in turn, can be used in a control loop to discharge a specific quantity of bulk material per unit of time from the dosing device, thus dosing the bulk material to be dispensed. Advantageously, the weighed system includes at least the receiving unit containing the bulk material to be dosed, and preferably also the discharge area and / or the discharge element.

[0125] The invention proposes a system comprising a metering device according to claims 1 to 9 and at least one extruder, wherein preferably (i) the extruder is provided in the main conveying direction downstream of the device, in particular the receiving unit, the discharge opening and / or the discharge element, and / or (ii) bulk material can be fed to the extruder, in particular via the discharge element, from the metering device, in particular metered.

[0126] It was surprisingly discovered that with such a system, it is particularly advantageous for the cleaning agent used to clean the metering device to also be used to rinse the extruder. In particular, this can be done in a single operation by feeding the cleaning agent directly into the extruder after it has been discharged from the metering device, for example, via the discharge element. Therefore, the bulk material to be metered by the metering device can advantageously be fed directly into the extruder's feed system (and the cleaning agent can then be fed in the same way).

[0127] From a process engineering perspective, the extruder is therefore advantageously coupled with the dosing device; in particular, the extruder follows the dosing device in the process chain.

[0128] This allows for particularly quick and easy changes in bulk material, as cleaning the dosing device and extruder (especially the parts in contact with the bulk material) is very simple and reliable. Consequently, the proposed system is particularly efficient and economical, even when used with different bulk materials. The ability to quickly change bulk materials enables a particularly high utilization of the system.

[0129] Regarding the other associated advantages, reference can be made to the previous explanations concerning the first and second aspects of the invention. These apply equally here.

[0130] Furthermore, a closure means, in particular a lid, is proposed for closing a main opening of a receiving unit of a metering device according to the invention, wherein a nozzle in the form of the first nozzle of the metering device is arranged on or in the closure means.

[0131] By providing a sealing agent with a suitable first nozzle, an existing dosing device can also be retrofitted in a surprisingly simple way with functionality for efficient cleaning, in particular a receiving unit.

[0132] Furthermore, a bearing element for supporting a discharge element of a metering device is proposed, wherein a nozzle in the form of the second nozzle and / or a nozzle in the form of the third nozzle of the metering device is arranged on or in the bearing element.

[0133] By providing a bearing element with a corresponding second and / or third nozzle, an existing dosing device can also be retrofitted in a surprisingly simple way with functionality for efficient cleaning, especially of a discharge area.

[0134] The invention proposes the use of a cleaning agent, in particular a granular cleaning agent, such as a cleaning granulate, for cleaning at least some parts and / or areas of a metering device that are in contact with or can be brought into contact with a bulk material to be metered during the metering operation of the device, such as at least one receiving unit of the metering device suitable for receiving bulk material, in particular an inner surface of the receiving unit, and for cleaning and / or rinsing an extruder following the metering device along a main conveying direction in one operation.

[0135] It was surprisingly discovered that a particularly simple and economical cleaning of a dosing device and an extruder, which is advantageously filled or fillable with a bulk material by the dosing device, is possible by using the cleaning agent both for cleaning the dosing device, for example to remove settled and / or adhering bulk material residues, and for cleaning and / or rinsing the extruder.

[0136] The invention proposes the use of a discharge element of a metering device for guiding and / or swirling a fluid, in particular into an area in the direction of gravity below the discharge element, blown from at least one nozzle along a main extension direction of the discharge element, particularly at least in an area in the direction of gravity below the discharge element.

[0137] It was surprisingly discovered that even in a hard-to-reach area of ​​the discharge section of a metering device, particularly efficient cleaning can be achieved by directing the fluid ejected from the nozzle onto the discharge element. This creates turbulence in the fluid, allowing any remaining bulk material to be removed from the device (e.g., a surface of the discharge area) with exceptional effectiveness.

[0138] The invention proposes a method for cleaning a metering device. In a metering device comprising a receiving unit for receiving bulk material to be metered, which is preferably feedable via a bulk material feed opening of the receiving unit and / or can be displaced from the receiving unit via a bulk material discharge opening towards a discharge opening of the device along a main conveying direction, wherein at least parts of bulk material residues deposited and / or adhering to an inner surface of the receiving unit are detached and / or conveyed towards the bulk material discharge opening of the receiving unit, it is proposed that at least within the receiving unit, at least in certain areas, a downward-directed fluid flow is formed as a cleaning fluid flow.

[0139] By shaping the fluid flow accordingly, the remaining bulk material can be removed from the receiving unit and discharged from the dosing device particularly efficiently.

[0140] Furthermore, reference can also be made to the previous explanations regarding the first and second aspects of the invention. These apply equally here.

[0141] The cleaning fluid flow is designed to form in the manner of a cyclone.

[0142] Alternatively or additionally, it can also be provided that the cleaning fluid flow within the receiving unit is formed along a flow path, wherein preferably the flow path runs at least sectionally and / or at least areawise along a spiral path, in particular with decreasing diameter, and / or from top to bottom with respect to the direction of gravity.

[0143] Alternatively or additionally, it can also be provided that the fluid flow is introduced into the receiving unit by a fluid jet ejected from a first nozzle, and wherein preferably the fluid jet is directed obliquely against an inner surface of the receiving unit and preferably at least partially deflects the fluid flow in a circumferential direction of the receiving unit.

[0144] Alternatively or additionally, it can also be provided that a fluid flow in the manner of a cyclone is formed within at least parts of the receiving unit through an interaction between the fluid jet and / or the fluid flow and the inner surface of the receiving unit.

[0145] Alternatively or additionally, it can also be provided that a cleaning agent, in particular a granular cleaning agent such as cleaning granules, is supplied to the fluid flow, which is preferably transported by the fluid flow at least temporarily and / or at least partially along the inner surface of the receiving unit, and in particular residues of bulk material are removed from the inner surface.

[0146] For example, the cleaning agent can be supplied to the receiving unit via the cleaning agent supply opening and / or bulk material supply opening.

[0147] Alternatively or additionally, it can also be provided that the cleaning agent is supplied to the fluid flow at a distance from the first nozzle.

[0148] For example, the first nozzle is positioned at a distance from the cleaning agent supply opening.

[0149] Alternatively or additionally, it can also be provided that the cleaning granules are fed into the fluid flow through the same opening through which the bulk material is fed into the receiving unit.

[0150] Alternatively or additionally, it can also be provided that the cleaning agent is added to the fluid flow after the cyclone has formed stably.

[0151] Alternatively or additionally, it may also be provided that the cleaning agent is introduced into the receiving unit, particularly via the first nozzle, together with the fluid jet as a mixture, in particular as a fluid-cleaning agent mixture.

[0152] Alternatively or additionally, it may also be provided that the cleaning agent and a fine fraction are separated from each other after exiting the dosing device, in particular by suctioning off the fine fraction and / or by dropping the cleaning granules parallel or inclined to the direction of gravity.

[0153] Reference can also be made to the explanations above.

[0154] Alternatively or additionally, it may also be provided that the cleaning agent exiting the dosing device is used to flush an extruder following the dosing device in the main conveying direction, in particular by passing the cleaning agent exiting the dosing device through the extruder.

[0155] Reference can also be made to the explanations above, including those regarding the use of a cleaning agent.

[0156] It is provided that the device has at least one discharge area which follows the receiving unit in the main conveying direction and / or which can be displaced from the receiving unit in the bulk material, in particular via the bulk material discharge opening of the receiving unit, and has a discharge element provided within the discharge area for discharging the bulk material from the discharge area in the direction of a discharge opening of the device. wherein preferably, in particular simultaneously with or before or after the formation of a cleaning fluid flow in the receiving unit, a fluid is blown into a coupling area in which coupling area the discharge element is connected to a drive element, such as a drive shaft.

[0157] Alternatively, a fluid is blown into the discharge area, in particular into an area surrounding the discharge element, such as an area in the direction of gravity below the discharge element.

[0158] In one embodiment, it can also be advantageous for the device to be configured to actuate the discharge element, in particular to rotate it, at least temporarily during the emission of a fluid jet via the first nozzle. In this way, an advantageous cleaning effect was also observed with regard to the receiving unit alone.

[0159] The invention proposes a method for cleaning a metering device, wherein the device has at least one receiving unit for receiving bulk material to be metered, which is preferably feedable via a bulk material feed opening of the receiving unit and / or can be displaced from the receiving unit via a bulk material discharge opening in the direction of a discharge opening of the device along a main conveying direction. wherein the device has at least one discharge area which follows the receiving unit in the main conveying direction and / or which is displaceable from the receiving unit in the bulk material, in particular via the bulk material discharge opening of the receiving unit, and has a discharge element provided within the discharge area for discharging the bulk material from the discharge area in the direction of a discharge opening of the device, wherein, in particular simultaneously with or before or after the formation of a cleaning fluid flow in the receiving unit, (i) a fluid is blown into the discharge area, in particular into an area existing around the discharge element, such as in an area in the direction of gravity below the discharge element, and / or (ii) a fluid is blown into a coupling area in which coupling area the discharge element is connected to a drive element, such as a drive shaft, is proposed.

[0160] This is based on the surprising finding that even hard-to-reach areas of the dosing device can be cleaned of bulk material residue by blowing a fluid into the discharge area and / or coupling area, thereby loosening the stuck bulk material.

[0161] This makes the cleaning process particularly efficient and cost-effective. Disassembling the dosing device to clean hard-to-reach areas is therefore no longer necessary.

[0162] It was discovered, surprisingly, that the discharge element can remain advantageously installed during cleaning and be used to agitate the introduced fluid flow. Thus, the cleaning effect can be significantly enhanced by the presence of the discharge element – ​​a completely unexpected finding.

[0163] The coupling area can be a separate and / or at least partially isolated area from the discharge area. Even in this case, cleaning as proposed is efficient, particularly simple, and thorough. The proposed solution is especially suitable for efficient and thorough cleaning if any bulk material lodged in the coupling area cannot be discharged through the discharge element.

[0164] The coupling area can be part of a bearing element for supporting the discharge element.

[0165] Furthermore, impairments to the discharge element, especially in the coupling area, caused by compacted bulk material can be avoided or at least reduced by providing one or more of the proposed first and second nozzles.

[0166] Furthermore, it was discovered that using the fluid flow(s) together with the cleaning fluid flow leads to surprising synergies. The combined application resulted in a cleaning performance that surpasses that achievable with the sequential use of the individual fluid flows. Brief description of the drawings

[0167] Further features and advantages of the invention will become apparent from the following description, in which preferred embodiments of the invention are explained with reference to schematic drawings.

[0168] This shows: Fig. 1a a schematic representation of a dosing device according to the first aspect of the invention; Fig. 1b a schematic top view of the dosing device of the Fig. 1a; Fig. 1c a schematic representation of a receiving unit of the dosing device made of Fig. 1a with sketched cleaning fluid flow in the manner of a cyclone; Fig. 1d a schematic representation of a coupling area of ​​the metering device made of Fig. 1a; Fig. 2 a schematic representation of a system according to the third aspect of the invention; and Fig. 3 a flowchart of a process according to the eighth aspect of the invention. Description of the embodiments

[0169] Fig. Figure 1a shows a schematic representation of a dosing device 1 according to the first aspect of the invention. Fig. Figure 1b shows the dosing device 1 schematically from above.

[0170] The metering device 1 has a receiving unit 3, the main opening 5 of which can be closed with a removable cover 7. The receiving unit 3 can hold a bulk material to be metered by the metering device 1, which can be fed into the receiving unit 3 via a bulk material feed opening 9 provided in the cover 7. The receiving unit 3 is conically shaped and has a slope in the direction of gravity (which in Fig. 1a (running along the negative Y-axis) has a decreasing inner diameter. Opposite and in the direction of gravity below the bulk material feed opening 9 is a bulk material outlet opening 11.

[0171] Bulk material can be transferred from the receiving unit 3 to a discharge area 13 of the device 1 via the bulk material discharge opening 11. Within the discharge area 13, a discharge element 15, here approximately in the form of a spiral, is provided for discharging the bulk material from the discharge area 13 towards a discharge opening 17.

[0172] The discharge opening 17 leads into a vertical discharge chute 19. Bulk material can be discharged from the metering device 1 via the vertical discharge chute 19 in the direction of gravity. The vertical discharge chute 19 has a suction opening 21, which is operatively connected to a dust extraction device 23.

[0173] During the dosing operation of the device 1, i.e., during the dosing of bulk material, residues 27 of the bulk material being dosed can accumulate and / or adhere over time to an inner surface 25 of the receiving unit 3 as well as to other parts of the device 1. If a change in the type of bulk material is planned, these bulk material residues 27 can lead to undesirable cross-contamination and must therefore be removed first.

[0174] Therefore, in order to be able to clean the device 1, for example when changing the type of bulk material, the metering device 1 has a first nozzle 29 arranged on the lid 7.

[0175] A fluid jet 31 can be ejected from the first nozzle 29 into the receiving unit 3. The first nozzle 29 is oriented such that the inner surface 25 of the receiving unit 3 is at least partially exposed to the ejected fluid jet 31, so that a fluid flow similar to a cyclone can be formed, at least partially, within the receiving unit 3 as a cleaning fluid flow. The device 1 is therefore specifically designed so that the ejected fluid jet 19 interacts with the inner surface 25 in such a way that the aforementioned cleaning fluid flow is formed.

[0176] As especially in Fig. 1b, where the fluid can be extracted, an area of ​​the inner surface 25 is obliquely (along a curvature of the inner surface 25 running along a circumferential direction of the receiving unit 3) approached by the ejected fluid jet 31. (Of course, in Fig. 1b. Due to the closed lid, the nozzle 27 and the fluid jet 29, as well as the inner surface, are not actually visible. However, this has been disregarded here for illustrative reasons.)

[0177] Due to the conical shape of the receiving unit 3, the fluid flow is forced onto a spiral path 33 with a decreasing diameter. This causes the velocity of the fluid flow to increase steadily. In particular, a vortex flow is formed by the interaction between the ejected fluid jet and the receiving unit (especially the curved inner surface). This cleaning fluid flow makes it particularly easy to remove bulk material residues 27 from the inner surface of the receiving unit.

[0178] The lid 7 of the receiving unit 3 has a cleaning agent feed opening 35 through which a cleaning agent can be fed into the interior of the receiving unit 3. This makes it possible, particularly after a cyclone has formed within the receiving unit 3, to introduce the cleaning agent into the cleaning fluid flow. The cleaning agent can, for example, be in granular form and be carried along the spiral path 33 by the cleaning fluid flow temporarily and / or section by section. The cleaning agent also reliably removes even strongly adhering bulk material residues 27 from the inner surface 25.

[0179] The cleaning agent supply opening 35 is located at a distance from the first nozzle 29, with both the first nozzle 29 and the cleaning agent supply opening 35 being offset from a (as in Fig. 1b are arranged in the vertical middle plane of the recording unit 3, which can be defined by the plane E.

[0180] Fig. Figure 1c shows a schematic representation of the receiving unit 3 of the dosing device 1 with a sketched fluid flow in the manner of a cyclone. The view is from above, looking down at the receiving unit 3, while the interior of the receiving unit 3 remains unobstructed with respect to the fluid flow. The particles 37 of the cleaning agent are also shown, which are carried along the downward spiral path 33 (and at least partially along the inner surface 25) by the cleaning fluid flow.

[0181] In the case of a powdered bulk material, the bulk material residues 27 are, for example, stirred up by the cleaning fluid flow and, due to their inertia and / or after the fluid jet has ceased supplying, settle in the discharge area 13 of the device 1, from where they can be removed from the device 1, e.g., by suction. For example, a dust component can be extracted upwards by the suction device 23, while the cleaning agent falls downwards (i.e., along the direction of gravity) in the discharge chute 19.

[0182] The metering device 1 also has a second nozzle 39 for injecting fluid into a dead space 41 located below the discharge element 15 in the direction of gravity. More precisely, the fluid 43 can be ejected with the second nozzle 39 in a direction perpendicular to the direction of gravity, namely parallel to the main extension direction of the discharge element 15 (i.e., in a direction parallel to the X-axis).

[0183] By ejecting fluid in this manner, bulk material located in the dead space 41 can be stirred up and / or discharged from the device 1, for example via the discharge opening 17, and in particular vacuumed up. Stirred-up bulk material could also be vacuumed up via another opening, for example. In this process, the fluid 43 ejected from the second nozzle 39 is swirled by the discharge element 15, thus supporting the cleaning effect of the fluid 43.

[0184] Furthermore, the metering device 1 also has a third nozzle 45 for injecting fluid into a coupling area 47, in which the discharge element 15 is connected to a drive element 49 (e.g., a drive shaft). Bulk material accumulated within the coupling area 47 cannot be displaced by the discharge element 15 and therefore remains within the device 1 without additional measures. By injecting fluid 51 within the coupling area 47, the bulk material located there can be agitated and / or discharged from the device 1, for example, via the discharge opening 17, and in particular, vacuumed out.

[0185] Both the first and the second nozzle 39, 45 are located in a bearing element 53 for supporting the discharge element 15, which also has the coupling area 47. Fig. Figure 1d shows a more detailed schematic representation of the in Fig. 1a marked area B of the device 1. In it, the bearing element 53 together with the coupling area 47 and the second nozzle 39 and the third nozzle 45 can be seen.

[0186] Fig. Figure 2 shows a schematic representation of a system 101 according to the third aspect of the invention.

[0187] System 101 includes a metering device 103 according to the first aspect of the invention. For example, it is the one relating to Fig. Dosing device 1a-1d discussed. Therefore, the features of the dosing device 103 are shown by way of example with the reference numerals of the ones relating to Fig. The dosing device 1 discussed in 1a-1d is provided.

[0188] Furthermore, system 101 includes an extruder 105. Bulk material from the dosing device 103 can be fed to the extruder 105 via the vertical discharge.

[0189] Following the cleaning of the dosing device 103, the cleaning agent can be fed to the extruder 105 in system 101 and used there to rinse the extruder 105. Thus, reliable cleaning of the dosing device 103 and rinsing of the extruder 105 are possible in a single operation.

[0190] Fig. Figure 3 shows a flowchart 201 of a method according to the eighth aspect of the invention.

[0191] The method relates to the cleaning of a metering device. The device has a receiving unit for receiving bulk material to be metered, which can be fed into the receiving unit via a bulk material feed opening and can be displaced from the receiving unit via a bulk material discharge opening towards a discharge opening of the device along a main conveying direction. The device can be a device according to the one described in relation to Fig.The device 1 discussed in 1a-d shall act in accordance with the first aspect of the invention.

[0192] For this purpose, a suitable dosing device is first provided in 201.

[0193] In 203, a downward-directed fluid flow is formed within the receiving unit, at least in certain areas, as a cleaning fluid flow (for example, on a spiral path with a decreasing diameter). For this purpose, a fluid jet is ejected from a first nozzle into the receiving unit, where it impacts an inner surface of the receiving unit and is forced onto a spiral path with a decreasing diameter. Preferably, the cleaning fluid flow is formed in the manner of a cyclone.

[0194] In 205, a cleaning agent is added to the fluid flow, which is transported by the fluid flow at least temporarily and / or at least partially along the inner surface of the receiving unit. The cleaning fluid flow and the cleaning agent enable a particularly reliable cleaning of the inner surface of the receiving unit.

[0195] This results in at least parts of the bulk material residues deposited and / or adhering to an inner surface of the receiving unit being detached and / or transported in the direction of the bulk material discharge opening of the receiving unit.

[0196] Furthermore, in 209, a fluid is blown into a dead space below a discharge element of the device by means of a second nozzle.

[0197] And in 211, a fluid is blown into a coupling area of ​​the device by means of a third nozzle. This occurs simultaneously with the introduction of the fluid jet from the first nozzle. A particularly advantageous cleaning effect has already been observed due to the superposition of the individual flows.

[0198] The features disclosed in the preceding description, in the drawings and in the claims can be essential to the invention in its various embodiments, both individually and in any combination. Reference symbol list 1 dosing device 3 recording units 5 Main opening 7 lids 9 Bulk material feed opening 11 Bulk material discharge opening 13 Discharge area 15 discharge element 17. Discharge opening 19 Vertical drop 21 Extraction opening 23 Extraction system 25 Inner surface 27 bulk material residues 29 First nozzle 31 Fluid jet 33 Spiral track 35 Cleaning agent feed opening 37 particles 39 Second nozzle 41 dead space 43 Fluid 45 Third nozzle 47 Clutch area 49 Drive element 51 Fluid 101 System 103 Dosing device 105 extruders 200 Flowchart 201 Providing a dosing device 203 Forming a cleaning fluid flow within a receiving unit of the dosing device 205 Adding a cleaning agent to the fluid flow 207 Removal of bulk material residues from an inner surface of the receiving unit 209 Blowing a fluid into a dead space below a discharge element of the metering device 211 Blowing a fluid into a coupling area of ​​the metering device Area B E Definable Level X, Y, Z coordinate axes

Claims

[1] Metering device (1) for bulk material, the device comprising at least - a receiving unit (3) for receiving bulk material to be dosed and - a discharge area (13) which follows the receiving unit (3) in the main conveying direction - - in which bulk material, in particular via a bulk material discharge opening (11) of the receiving unit (3), can be displaced from the receiving unit (3), and - a discharge element (15) provided within the discharge area (13) for discharging the bulk material from the discharge area (13) towards a discharge opening (17) of the device, - a first nozzle (29) for at least temporarily ejecting a fluid jet (31) into the receiving unit (3), - - wherein the first nozzle (29) is oriented such that an inner surface (25) of the receiving unit (3) can be exposed at least partially to the fluid jet (31) in order to form a fluid flow in the manner of a cyclone as a cleaning fluid flow at least partially within the receiving unit (3) and characterized by , that a second nozzle (45, 39) is provided for injecting fluid into a coupling area (47) in which coupling area (47) the discharge element (15) is connected to a drive element (49), such as a drive shaft. [2] Metering device (1) according to claim 1, wherein at least one further nozzle (39, 45) is provided for blowing fluid into at least one area surrounding the discharge element. [3] Dosing device (1) according to one of the preceding claims, wherein (i) the further nozzle (39) is provided for blowing fluid into a dead space (41) in the direction of gravity below the discharge element (15) and / or the further nozzle (39) is arranged on or in a bearing element for bearing the discharge element; (ii) with the further nozzle (39) the fluid can be ejected along a direction perpendicular to the direction of gravity and / or parallel or antiparallel to the main extension direction of the discharge element; (iii) at least two further nozzles (39) are provided with which fluid can be injected in two opposite directions into the area around the discharge element (15), in particular into the dead space, wherein preferably at least one of the further nozzles (39) is provided at each of the two ends of the discharge area (13); and / or (iv) the fluid can be discharged with the second nozzle (45) in a direction perpendicular to the main extension direction of the discharge element (15) and / or the second nozzle (45) is arranged on or in the bearing element. [4] Metering device (1) according to one of the preceding claims, wherein the first nozzle (29) is oriented such that, in particular relative to the receiving unit (3), preferably to the inner surface (25) of the receiving unit (3), the fluid jet (31) ejected from the first nozzle (29) can be deflected by means of an impact area of ​​the inner surface (25) of the receiving unit (3). [5] Metering device (1) according to one of the preceding claims, wherein the first nozzle (29) is arranged on a lid (7) of the receiving unit (3), in particular such that when the lid (7) is closed the first nozzle (29) projects at least partially into the receiving unit (3). [6] Metering device (1) according to one of the preceding claims, wherein the first nozzle (29), in particular at least during the metering and / or cleaning operation of the device, is arranged in the receiving unit (3) such that it is positioned above a defined level, in particular relative to a maximum permissible fill level of bulk material in the receiving unit (3) during the metering operation of the metering device (1). [7] Dosing device (1) according to one of the preceding claims, wherein the device has a reservoir for receiving a cleaning agent, in particular a granular cleaning agent, such as cleaning granules, and / or is connected or connectable to such a reservoir. [8] Dosing device (1) according to one of the preceding claims, wherein the device, in particular in the lid (7) of the receiving unit (3), has a cleaning agent supply opening for supplying the cleaning agent, in particular from the storage container, into the interior of the receiving unit (3), wherein preferably the lid (7) of the receiving unit (3) has the cleaning agent supply opening. [9] Metering device (1) according to one of the preceding claims, wherein the discharge opening (17) opens into a discharge element (19), in particular having a nozzle, a vertical discharge and / or a drop pipe, wherein preferably (i) bulk material can be discharged from the metering device (1) via the discharge element (19) in a direction parallel or inclined, in particular at an angle of less than 90°, to the direction of gravity and / or (ii) the discharge element (19) has a suction opening (21) for suctioning a fine fraction, in particular dust and / or the suction opening (21) and / or the discharge opening (21) is or can be connected to a suction device (23) for suctioning dust. [10] System (101) comprising a metering device (1) according to one of the preceding claims and at least one extruder (105), wherein preferably (i) the extruder (105) is provided in the main conveying direction after the device (1), in particular the receiving unit (3), the discharge opening (17) and / or the discharge element (19), and / or (ii) bulk material from the metering device (1) can be fed to the extruder (105), in particular via the discharge element (19), in particular metered. [11] Method for cleaning a metering device (1), in particular a metering device (1) according to any one of claims 1 to 9, wherein at least parts of residues of bulk material deposited and / or adhering to an inner surface (25) of the receiving unit (3) are removed and / or conveyed in the direction of the bulk material discharge opening (11) of the receiving unit (3) by forming at least partially downward directed fluid flow as a cleaning fluid flow at least within the receiving unit (3), wherein, in particular, simultaneously with or before or after the formation of the cleaning fluid flow in the receiving unit (3), a fluid from a further second (45, 39) is blown into a coupling area (47) in which coupling area (47) the discharge element (15) is connected to a drive element (49), such as a drive shaft. [12] Method according to claim 11, wherein a fluid is blown from a further nozzle (39, 45) into the discharge area (13), in particular into an area surrounding the discharge element (15), such as in an area in the direction of gravity below the discharge element (15). [13] Method according to claim 11 or 12, wherein (i) the cleaning fluid flow is formed in the manner of a cyclone; (ii) the fluid flow is introduced into the receiving unit (3) by means of a fluid jet (31) ejected from a first nozzle (29), and wherein preferably the fluid jet (31) is directed obliquely towards an inner surface (25) of the receiving unit (3) and preferably at least partially deflects the fluid flow (31) in a circumferential direction of the receiving unit (3); (iii) through an interaction between the fluid jet (31) and / or the fluid flow and the internal surface (25) of the receiving unit (3) a fluid flow of the type of a cyclone is formed within at least parts of the receiving unit (3); (iv) a cleaning agent, in particular a granular cleaning agent, such as cleaning granules, is supplied to the fluid flow, which is preferably transported by the fluid flow at least temporarily and / or at least partially along the inner surface(25) of the receiving unit (3), and in particular residues of bulk material are removed from the inner surface (25); (v) the cleaning agent is added to the fluid flow after the cyclone has formed stably; (vi) the cleaning agent and a fine fraction are separated from each other after exiting the dosing device (1), in particular by suctioning off the fine fraction and / or by discharging the cleaning granules parallel or inclined to the direction of gravity; and / or (vii) an extruder (105) following the metering device (1) in the main conveying direction is flushed with the cleaning agent exiting the metering device (1), in particular by passing the cleaning agent exiting the metering device (1) through the extruder (105).

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