Nozzle assembly for powder handling equipment

Abstract

An apparatus (1) and method for processing food powders comprises: a sealable container (2) having an inner surface (3) and a powder outlet (5), the inner surface (3) defining a volume (4) in which food powders are processed; and a nozzle arrangement (6) attached to the container (2) and configured to feed air into the container (2). The nozzle arrangement (6) has a plurality of jet nozzles (7, 8, 9), the plurality of jet nozzles (7, 8, 9) being configured to direct air toward the inner surface (3) to remove product powder from the inner surface (3), so that the air and the removed product powder can flow out of the container (2) through the powder outlet (5).

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for cleaning equipment for processing food powders. Background Art

[0002] Product powders can be used to produce a variety of food products. Using product powders is advantageous because powders can be stored for long periods of time without spoiling. Powders can also be easily dissolved in liquids to form the desired product. Food products formed from powders can include dairy beverages, such as milk; non-dairy beverages, such as soft drinks; and other dairy products, such as ice cream, yogurt, or cheese. Product powders can include raw materials, such as sugar, milk powder, salt, or flour; or finished products, such as instant formulas, instant beverages, or dried bouillon. Raw milk powder can be used when producing milk substitutes that are similar to fresh milk. Raw milk powder dissolves easily in water and forms reconstituted liquid milk, which undergoes further processing, including filtering, homogenization, and heat treatment, to form the final beverage product. Other forms of food powders are ingredients that are mixed together to form baking mixes and cake mixes.

[0003] Product powders may require a mixing process, which typically occurs in a sealable container that includes a stirring device, paddle mixer, or other suitable mixing device. After mixing and emptying the product mixture from the sealable container, residual powder may remain on the inner wall of the sealable container. Traditional methods for cleaning the inner wall involve maintenance personnel manually removing the powder using an industrial vacuum cleaner. A disadvantage of traditional cleaning methods is that the cleaning process is labor-intensive. Traditional cleaning methods may also require opening the container, making the interior of the container susceptible to contamination. Summary of the Invention

[0004] It is an object of the present invention to at least partially overcome one or more limitations of the prior art. In particular, it is an object to provide an apparatus and method that enable efficient cleaning of equipment for processing food powders.

[0005] According to one aspect of the present invention, an apparatus for processing food powder includes a sealable container having an inner surface defining a volume in which food powder is processed; a powder outlet; and a nozzle arrangement attached to the container and configured to feed air into the container. The nozzle arrangement includes a plurality of jet nozzles configured to direct air toward the inner surface to remove product powder from the inner surface, such that the air and the removed product powder can flow out of the container through the powder outlet.

[0006] Therefore, cleaning according to the present invention is not performed in the traditional manner (i.e., by opening the container and manually removing the powder from the inner surfaces and moving it out of the container using a vacuum cleaner). Instead, the powder is removed from the inner surfaces using jet nozzles that direct air toward the inner surfaces, and the removed powder and air can be extracted from the container. An advantage of the device for processing food powders described herein is that it allows for very efficient and hygienic cleaning. The container can remain closed during the cleaning process. The device includes multiple sets of jet nozzles arranged to direct air streams toward different walls of the container, and the jet nozzles can be arranged to have predetermined impact angles for the air streams striking the respective surfaces. The arrangement of the jet nozzles helps ensure that the powder is removed from the respective surfaces, so that the powder can be extracted from the container.

[0007] According to another aspect of the present invention, a method for cleaning an apparatus for processing food powder is provided, the apparatus comprising a sealable container having an inner surface defining a volume for processing food powder therein and a powder outlet. The method comprises feeding air into the container using a nozzle arrangement attached to the container, wherein the air is directed toward the inner surface via a plurality of jet nozzles to remove product powder from the inner surface; and extracting the air from the container such that the air and the removed product powder can flow out of the container through the powder outlet.

[0008] The method may comprise the same features and have the same advantages as the apparatus for processing food powders.

[0009] Other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Features of the present invention will now be described by way of example with reference to the accompanying schematic drawings.

[0011] Figure 1 is a perspective cutaway view of equipment used to process food powders.

[0012] Figure 2 yes Figure 1 A perspective cutaway view of an apparatus for processing food powders, including a stirring device.

[0013] Figure 3 yes Figure 1 Front cross-sectional view of the device.

[0014] Figure 4 yes Figure 1 A side sectional view of the device.

[0015] Figure 5 yes Figure 1 A front cross-sectional view of the device showing the air flow path within the container.

[0016] Figure 6 yes Figure 1 Schematic diagram of the control system of the equipment.

[0017] Figure 7 Is used for cleaning and Figure 1 A flow chart of a method of a device similar to that of a device. DETAILED DESCRIPTION

[0018] Embodiments of the present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. The present invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0019] First reference Figure 1 , shows an apparatus 1 for processing food powder. Apparatus 1 comprises a sealable container 2 having an inner surface 3 defining a volume 4 in which the food powder is processed, and a powder outlet 5. Apparatus 1 can be oriented horizontally, with powder outlet 5 disposed at the bottom of apparatus 1. A nozzle arrangement 6 is attached to container 2 and configured to feed air into container 2 for removing residual food powder from container 2 during a cleaning process (which occurs after as much food powder as possible has been removed from container 2) for packaging or further processing. Nozzle arrangement 6 comprises a plurality of jet nozzles 7, 8, and 9 configured to direct air toward inner surface 3 to remove product powder therefrom. After removing product powder from inner surface 3, the air and removed product powder exit container 2 through powder outlet 5.

[0020] Additional references Figure 2 Processing the food powder in the container 2 may include stirring or mixing the food powder to produce the food product. Figure 2 An exemplary mixing arrangement of apparatus 1 is shown. The food product may be a beverage product, such as a dairy beverage or a non-dairy beverage. The beverage product may include milk or a soft drink. The food product may include other non-beverage foods, such as ice cream, yogurt, or cheese. The product powder may include any suitable ingredients to form the desired food product. The product powder may include raw materials, such as sugar, milk powder, salt, or flour, or finished products, such as instant formulas, instant beverages, or dried bouillon. Other product powders may be suitable. Apparatus 1 is not necessarily intended for stirring or mixing food powders. For example, apparatus 1 may be used to convey product powders, and nozzle arrangement 6 may be used to clean apparatus 1 after removing product powder from container 2.

[0021] The inner surface 3 of the container 2 is defined by a first side wall 10, a second side wall 11 opposite the first side wall 10, and a rear wall 12 of the container 2 extending between the first side wall 10 and the second side wall 11. Figure 2As shown, the front wall 13 is arranged opposite the rear wall 12. The front wall 13 can be formed as a pivotable door of the container 2 and can be attached to the container 2 by a handle and hinge 14. A top surface or roof 15 extends between the first and second side walls 10, 11 and between the rear wall 12 and the front wall 13. The side walls 10, 11 can be inclined relative to the horizontally extending roof 15. The container 2 and the inner surface 3 can have any suitable shape and the shape can depend on the application, for example, whether the container 2 is used to accommodate a mixing or stirring device or is used for transportation.

[0022] like Figure 2 As shown, rotatable stirring devices 16, 17 for stirring or mixing product powder can be mounted on the rear wall 12 and extend through the volume 4 of the container 2 when the device 1 is assembled. The rotatable stirring devices 16, 17 can include a first rotatable shaft and a second rotatable shaft, each of which includes a mixing paddle 18. The rotatable shafts rotate in the same or opposite directions relative to each other during mixing of the product powder. The shape of the container 2 can be formed to accommodate the rotation of the first rotatable shaft and the second rotatable shaft. The side walls 10, 11 of the container 2 can each be formed to have a concave shape on their inner sides at the bottom of the container 2, so that each rotatable shaft is accommodated in the circular cavity 2a, 2b of the container 2. Other shapes can be suitable for the container 2. The motor 19 is arranged outside the container 2 and coupled to the rotatable stirring devices 16, 17 to rotate them. Any suitable motor or drive mechanism can be provided.

[0023] The nozzle arrangement 6 includes multiple sets of jet nozzles 7, 8, and 9 mounted to the container 2 and arranged to direct airflow toward the inner surface 3. The distribution of the multiple sets of jet nozzles 7, 8, and 9 within the nozzle arrangement 5 depends on the shape of the container 2. The multiple sets of jet nozzles 7, 8, and 9 are arranged to ensure coverage of the entire area of ​​the inner surface 3, meaning that product powder can be removed from the entire surface area of ​​the inner surface 3. The multiple sets of jet nozzles 7, 8, and 9 can have an asymmetrical distribution along the inner surface 3 of the container 2, and each jet nozzle in the multiple sets of jet nozzles 7, 8, and 9 can be arranged tangentially relative to a corresponding wall 10, 11, 12, and 13. Each set of jet nozzles 7, 8, and 9 can correspond to a different wall 10, 11, 12, and 13 to direct air at the corresponding wall 10, 11, and 12. The jet nozzles within a single set can be evenly spaced and mounted in similar orientations relative to the same wall 10, 11, 12, and 13.

[0024] Figure 1 shows three different groups of jet nozzles 7, 8, and 9. The first group of jet nozzles 7 includes jet nozzles 7 and 20, which are arranged to direct airflow toward the sidewalls 10 and 11. The jet nozzles 7 and 20 can be evenly spaced and angled relative to the respective sidewalls 10 and 11. The jet nozzles 7 correspond to the first sidewall 10, and the jet nozzles 20 correspond to the second sidewall 11. Any suitable number of jet nozzles 7 and 20 can be used, for example, three or more jet nozzles per sidewall 10 and 11. Each sidewall 10 and 11 can have four jet nozzles, arranged in an upper position along the respective sidewall 10 and 11 and configured to direct air at the respective wall 10 and 11. The jet nozzles 7 corresponding to the first sidewall 10 can have the same orientation and angle relative to the first sidewall 10. Similarly, the nozzles 20 corresponding to the second sidewall 11 can have the same orientation and angle relative to the second sidewall 11. The jet nozzle 7 and the jet nozzle 20 may be arranged symmetrically with respect to each other to direct the air flow downwardly along the respective side walls 10 , 11 to remove powder therefrom.

[0025] The second set of jet nozzles 7 includes jet nozzles 8, 21, which are arranged to direct an air flow toward the top plate 15 to remove product powder therefrom. The second set of jet nozzles 8, 21 can be arranged perpendicularly relative to the first set of jet nozzles 8, 20, so that the second set of jet nozzles 8, 21 is arranged along a line parallel to the rear wall 12 and the front wall 13, while the first set of nozzles 7, 20 is arranged along a line parallel to the side walls 10, 11. The jet nozzle 8 is arranged near the rear wall 12, and the jet nozzle 21 is arranged relative to the jet nozzle 8 and is arranged near the front wall 13 (as shown in FIG. Figure 2 (shown in FIG. 1 ). The jet nozzles 8 and jet nozzles 21 can be arranged symmetrically relative to each other, so that each set of jet nozzles 8, 21 directs airflow toward the opposite set of jet nozzles 8, 21 along the top plate 15. Any suitable number of jet nozzles 8, 21 can be used, such as three or more jet nozzles. Four jet nozzles can be arranged adjacent each of the rear wall 12 and the front wall 13.

[0026] The third set of jet nozzles 9 includes jet nozzles 9 and 22, which are arranged to direct airflow toward the center of the container 2 or any other common location for collecting removed powder. The jet nozzles 9 and 22 can be angled relative to the top plate 15 and side walls 10 and 11 to direct the airflow that moves removed powder from the top plate and side walls 10 and 11 toward the center of the container 2, allowing air and powder to be drawn out of the container through the powder outlet 5. The jet nozzle 9 can be arranged near the first side wall 10, and the jet nozzle 22 can be arranged near the second side wall 11. The jet nozzles 9 and 22 can be arranged symmetrically relative to each other. Any suitable number of jet nozzles 9 and 22 can be used. Three jet nozzles can be arranged near each of the side walls 10 and 11.

[0027] The first, second, and third groups of jet nozzles 7, 8, 9 can be operated at different times, and different jet nozzles within a group can also be operated at different times. The operation of each jet nozzle in the nozzle arrangement 6 can be controlled using a control valve 23 for each jet nozzle, which independently controls the air passing through the corresponding jet nozzle. The control valve 23 can include any suitable actuating device, such as a solenoid. Each control valve 23 is fluidically connected to a pressurized air source (not shown) via a supply line 24. The pressurized air source is connected to the supply line 24 via an air supply pipe (not shown). The supplied air can be filtered, sterilized, or dried, and the source can be a compressor. The air pressure in the supply line 24 can be maintained at a constant value.

[0028] During the cleaning process, the control valves 23 corresponding to the first and second groups of jet nozzles 7, 8 can be opened first to direct the air flow at the top plate 15 and side walls 10, 11 to remove the powder. After the product powder is removed from the inner surface 3, the first and second groups of jet nozzles 7, 8 can be closed, and the control valve 23 corresponding to the third group of jet nozzles 9 can be opened to direct the removed powder and air toward the center of the container 2. Figure 6 Suction (schematically shown in FIG) can be used to draw the removed powder and air out of the container 2 through the powder outlet 5. The powder outlet 5 can be opened and closed by a valve located in the passage of the powder outlet. The valve can be operated by an actuator 25 configured to open and close the valve.

[0029] Now refer to Figure 3 , a front sectional view of an apparatus 1 comprising a nozzle arrangement 6 and rotatable stirring means 16 , 17 is shown. Figure 3A conduit 26 is shown which is configured to supply air to a respective jet nozzle and for mounting each jet nozzle 7, 8, 9 to the vessel 2. The conduit 26 may be welded to the periphery of the vessel 2 and extend into the volume 4 to hold the jet nozzles 7, 8, 9 within the vessel 2. Each conduit 26 is fluidly connected to a respective control valve 23 and Figure 1 The supply line 24 is shown. The supply line 24 can also be formed by a pipe branching through the container 2. Any other suitable mounting parts, brackets, clips, hooks, bolts, screws, etc. can be used to fix the nozzle device 6 to the container 2.

[0030] Each jet nozzle 7, 8, 9 is arranged to direct the airflow at the corresponding surface so that the airflow impacts the surface at a predetermined angle of impact. The first set of jet nozzles 7, corresponding to sidewalls 10, 11, includes jet nozzles arranged to direct the airflow toward the first or second sidewall 10, 11 at an angle of impact θ1 between 5 and 25 degrees relative to the corresponding sidewall 10, 11. The angle of impact θ1 can be between 10 and 20 degrees, or between 12 and 18 degrees. The angle of impact θ1 can be defined as the angle between the airflow direction F and the tangent direction T of the surface at the airflow's impact point 28. The airflow's impact point 28 on the corresponding sidewall 10, 11 can be between 10 and 80 centimeters from the jet nozzle 7 outlet, or even outside this range. As also shown in FIG3 , the third set of jet nozzles 9 is angled away from the walls 10, 11 to direct the airflow toward the horizontal center plane C of the container 2. The center plane C can be defined as the horizontal plane that divides the volume 4 into two volumes of equal size.

[0031] Now refer to Figure 4 , shows a side view of the device 1. The conduit 26 for the second set of jet nozzles 8 may alternatively be as Figure 4 As shown, it is attached to the rear wall 12 or the front wall 13. The second set of jet nozzles 8 is arranged to direct the air flow towards the top plate 15. The impact angle θ2 of the air flow hitting the top plate 15 is between 5 and 25 degrees relative to the top plate 15. The impact angle θ2 can be between 10 and 20 degrees, or even between 8 and 18 degrees. The impact point 29 of the air flow on the top plate 15 can be between 10 and 80 centimeters from the outlet of the jet nozzle 8, or even outside this range. Figure 4 As best shown in FIG, each jet nozzle 7, 8, 9 may comprise a flat fan nozzle having a fan-shaped outlet 30 configured to eject air across the respective surface in a fan-shaped air flow pattern. Other types of nozzles may be suitable, and different groups of jet nozzles 7, 8, 9 may have the same or different types of nozzles.

[0032] Now refer to Figure 5, shows the air flow path in the container 2 of the apparatus 1. The air flow path may be continuous around the inner surface 3. Air may be fed to the set of jet nozzles 7, 8, 9 at any suitable flow rate. The flow rate may be from 40 to 200 standard cubic meters per hour (Nm3) per square meter of the area of ​​the inner surface 3 of the container 2. 3 / h). "Normal cubic meter" means one cubic meter of air at a pressure of 1.01325 bar and a temperature of zero degrees. The feeding of air can also be carried out at a flow rate of 40 to 200 cubic meters per hour, wherein the air has the same temperature and pressure as the air surrounding the device 1. The internal surface area may include the area of ​​rotatable stirring devices 16, 17 (as shown in Figures 2 and 3) or any other mixing device arranged in the container 2. Feeding air may include changing the air flow through at least one of the jet nozzles 7, 8, 9 to temporarily increase the air flow through the corresponding jet nozzle 7, 8, 9, so that the air is supplied in a pulsed manner. The flow rate during feeding depends on the application. In an exemplary application, the flow rate of the air feed may be between 110 and 130 Nm 3 / h, or between 110 and 130 m 3 Feeding air to the jet nozzles 7 , 8 , 9 may comprise feeding air at a flow rate providing an air velocity of at least 5 meters per second (m / s) at the impact point 28 .

[0033] Air can be drawn from the container 2 at any suitable flow rate. The flow rate of air drawn from the container 2 can be between 60 and 240 Nm per square meter of the inner surface 3 of the container 2. 3 / h, or 60 to 240m 3 / h (ambient temperature and pressure). The flow rate during suction depends on the application. In an exemplary application, the flow rate of the suction air can be between 130 and 150 Nm 3 / h, or between 130 and 150 m 3 / h (ambient temperature and pressure).

[0034] like Figure 5 As shown, the first set of jet nozzles 7 can be configured to direct air flow 31 downwardly along the side walls 10, 11. The shape of the container 2 can force the air to flow concavely upwardly from the bottom of the container 2 toward the horizontal center plane C. The second set of jet nozzles 8 can be configured to direct air flow 32 along the top plate 15. The air flow 32 can be directed from the rear of the container 2 toward the front of the container 2, or vice versa, so that after the air passes through the top plate 15, it hits the front wall 13 and the rear wall 12 (as shown in FIG. Figure 2). The third set of jet nozzles 9 is configured to direct the air flow toward the horizontal center plane C of the container 2. The nozzles can be operated intermittently so that no air flows collide with and interfere with each other.

[0035] Figure 6 An exemplary control system 45 is shown for the apparatus 1. The cleaning process can be automated using the control system 45, which includes a processor 34 communicatively coupled to the control valve 23 for actuating the control valve 23 and a pneumatic delivery system 35 configured to supply air to the nozzle arrangement 6. The control valve 23 can be a solenoid valve and the processor 34 can include any suitable processor and electronic control mechanism, such as a central processing unit (CPU), a microprocessor, a control circuit, etc.

[0036] The pneumatic transmission system 35 may include a compressor, and the control system 45 may control the compressor to deliver the pneumatic air at a predetermined flow rate (eg, 40 to 200 Nm 3 Air is fed into supply line 24 at a flow rate between 100 and 200 psi (1000 psi and 1000 psi) per hour. A control system 45 can be used to maintain a constant pressure in supply line 24. Processor 34 can sequentially activate jet nozzles 7, 8, and 9 of nozzle assembly 6 to provide a time-varying air flow through the jet nozzles for air supplied to container 2. Control system 45 can also be used to vary the air flow through at least one jet nozzle to temporarily increase the air flow through the jet nozzle. Control system 45 can be used to provide any specific sequence of air flows within container 2. Pulsated air flow, alternating air flow velocities, and different flow rates for different jet nozzles can be provided.

[0037] The pneumatic transport system 35 may also be fluidly connected to the vacuum pump 25 to create a suction action (e.g., to draw air and powder out of the powder outlet 5 of the container 2) to create a suction action (e.g., to draw air and powder out of the powder outlet 5 of the container 2). Figure 1 ). The vacuum pump can operate independently of the nozzle arrangement 6. The container 2 can be sealed so that air can only be exhausted through the powder outlet 5. If more air is extracted from the container 2 than is supplied to the container 2, the container 2 can include another additional inlet valve 36 for supplying more air into the container 2. The inlet valve 36 can be a one-way valve that allows air to pass through the valve in one direction into the supply line 24 of the container 2. The inlet valve 36 can be arranged as part of the container 2 or external to the container 2. Any suitable sensor 37, such as a pressure sensor for detecting the pressure in the supply line 24, can be part of the apparatus 1, so that the processor 34 can activate the inlet valve 36 and the control valve 23 in response to data detected by the sensor 37. Alternatively, the inlet valve 36 is a conventional mechanical pressure (vacuum) relief valve.

[0038] Now refer to Figure 7, a method 38 for cleaning an apparatus for processing food powders is shown. The apparatus 1 and Figure 6 The control system 45 shown can be used to perform method 38. Method 38 includes step 39 of feeding air into container 2 using nozzle device 6 attached to container 2. The air is directed toward the inner surface 3 by a plurality of jet nozzles 7, 8, 9 to remove product powder from the inner surface 3. Step 39 may include feeding the air at a speed of 40 to 200 Nm per square meter of the inner surface area of ​​container 2. 3 3. The step 39 may comprise feeding air into the container 2 at a flow rate of at least 5 m / s at the impact points 28, 29 of the air against the inner surface 3 of the container 2. The step 39 may comprise altering the air flow through the at least one jet nozzle 7, 8, 9, thereby temporarily increasing the air flow through the at least one jet nozzle 7, 8, 9 and causing the powder to be released from the inner surface 3.

[0039] Step 40 of method 38 includes activating the jet nozzles 7, 8, and 9. Step 40 may include sequentially activating the jet nozzles 7, 8, and 9 such that feeding air into the container 2 provides a time-varying air flow through the jet nozzles 7, 8, and 9. Step 40 may include activating the nozzles to remove powder, and step 41 may include activating the jet nozzles to direct the removed powder toward the center of the container 2. During step 40, the first and second sets of jet nozzles 7, 8 may be activated, and during step 41, the third set of jet nozzles 9 may be activated. The activation of the jet nozzles during either step 40 or step 42 may also be sequential.

[0040] Step 42 of method 38 includes extracting air from container 2 so that the air and the removed product powder can flow out of container 2 through powder outlet 5. Step 42 may include evacuating the air from container 2 at a rate of 60-240 Nm per cubic meter of volume defined by inner surface 3 of container 2. 3 Air is drawn from the container 2 at a flow rate of 1 / h, or at another flow rate as previously described. Method 38 is a dry cleaning method, ie no liquid is supplied to the sealable container 2 when the method is performed.

[0041] An apparatus 1 for processing food powders, including a nozzle assembly 6, facilitates more efficient cleaning of the apparatus. The jet nozzles in the nozzle assembly are configured to direct airflow at the inner surface of a sealable container to remove residual product powder from the inner surface. The removed product powder and air can then exit the container via a powder outlet and a vacuum pump, thereby reducing or eliminating manual cleaning of the apparatus. In addition to providing a more efficient cleaning process, the use of the nozzle assembly advantageously enables a more hygienic cleaning process because the container remains sealed during the cleaning process.

[0042] From the above description it is apparent that, although various embodiments of the invention have been described and shown, the invention is not restricted thereto, but may also be embodied in other ways within the scope of the subject matter defined in the appended claims.

Claims

1. An apparatus (1) for processing food powder, the apparatus (1) comprising: a sealable container (2) having an inner surface (3) defining a volume (4) in which the food powder is processed, and a powder outlet (5), the inner surface (3) comprising a front wall (13) and a rear wall (12) opposite the front wall (13), a top panel (15) extending between the front wall (13) and the rear wall (12), and a first side wall (10) and a second side wall (11) opposite the first side wall (10); and a nozzle arrangement (6) attached to the container (2) and configured to feed air into the container (2), wherein The nozzle arrangement (6) comprises a plurality of jet nozzles configured to direct air towards the inner surface (3) to remove product powder from the inner surface (3), such that the air and the removed product powder can flow out of the container (2) through the powder outlet (5), characterized in that: The device (1) is a mixing device comprising at least one rotatable stirring device for the food powder, the rotatable stirring device being mounted on a rear wall (12) and extending through the volume (4) of the container (2) when the device (1) is assembled, the rotatable stirring device comprising a first rotatable shaft and a second rotatable shaft, the container (2) being shaped to accommodate the rotation of the first rotatable shaft and the second rotatable shaft, The plurality of jet nozzles are arranged to ensure coverage of the entire area of ​​the inner surface (3), thereby removing product powder from the entire surface area of ​​the inner surface (3), wherein the plurality of jet nozzles include a first group of jet nozzles arranged to direct air flow toward the first side wall (10) and the second side wall (11), a second group of jet nozzles arranged to direct air flow toward the top plate (15), and a third group of jet nozzles arranged to direct air flow toward the horizontal center plane (C) of the sealable container (2), wherein the first side wall (10) and the second side wall (11) are each formed to have a concave shape on their inner sides at the bottom of the container (2), the first group of jet nozzles is configured to direct air flow downwardly along the first side wall (10) and the second side wall (11), so that the shape of the container (2) forces the air to flow concavely upwardly from the bottom of the container (2) toward the horizontal center plane (C), and The internal surface area includes the area of ​​the rotatable stirring device.

2. The apparatus (1) according to claim 1, wherein the first set of jet nozzles is arranged to direct air flow towards the first side wall (10) and the second side wall (11) so that the air flow (31) directed towards the first side wall (10) and the second side wall (11) hits the first side wall (10) and the second side wall (11) at an impact angle (θ1) between 5 and 25 degrees relative to the corresponding side wall (10, 11).

3. The apparatus (1) according to claim 1, wherein the second set of jet nozzles is arranged to direct the air flow towards the top plate (15) so that the impact angle (θ2) of the air flow directed towards the top plate (15) hitting the top plate (15) is between 5 and 25 degrees relative to the top plate (15).

4. The apparatus (1) according to any one of claims 1 to 3, wherein the plurality of jet nozzles comprises a flat fan jet nozzle (30) arranged to spray the air in a fan-shaped air flow pattern.

5. Apparatus (1) according to any one of claims 1 to 3, wherein the nozzle arrangement (6) comprises a plurality of control valves (23), the plurality of control valves (23) being configured to independently control the air flows through different ones of the plurality of jet nozzles such that the air flows through at least some of the different jet nozzles are different.

6. A method for cleaning an apparatus (1) for processing food powder, the apparatus (1) comprising a sealable container (2), the sealable container (2) having an inner surface (3) and a powder outlet (5), the apparatus (1) being a mixing apparatus comprising at least one rotatable stirring device for the food powder, the rotatable stirring device comprising a first rotatable shaft and a second rotatable shaft, the container (2) being shaped to accommodate the rotation of the first rotatable shaft and the second rotatable shaft, the first side wall (10) and the second side wall (11) each being formed to have a concave shape on their inner side at the bottom of the container (2), the inner surface (3) defining a volume (4) in which the food powder is processed, the inner surface (3) comprising a front wall (13) and a rear wall (12) opposite the front wall (13). , a top plate (15) extending between the front wall (13) and the rear wall (12), the first side wall (10), and the second side wall (11) opposite to the first side wall (10), the method comprising: feeding air into the container (2) using a nozzle arrangement (6) attached to the container (2), wherein the air is directed toward the inner surface (3) by a plurality of jet nozzles to remove product powder from the inner surface (3); and Air is sucked from the container (2) so that the air and the removed product powder can flow out of the container (2) through the powder outlet (5), characterized in that: The jet nozzles are arranged to ensure coverage of the entire area of ​​the inner surface (3), so that product powder can be removed from the entire surface area of ​​the inner surface (3), wherein the plurality of jet nozzles include a first group of jet nozzles arranged to direct air flow toward the first side wall (10) and the second side wall (11), a second group of jet nozzles arranged to direct air flow toward the top plate (15), a third group of jet nozzles arranged to direct air flow toward the horizontal center plane (C) of the sealable container (2), and The internal surface area includes the area of ​​the rotatable stirring device.

7. The method according to claim 6, wherein the feeding of air comprises feeding the air into the sealable container (2) at a flow rate of 40 to 200 Nm per square meter of the inner surface area of ​​the sealable container (2). 3 / h.

8. A method according to claim 6, wherein the feeding of air comprises feeding the air into the sealable container (2) at a flow rate providing a velocity of the air of at least 5 m / s at the point of impact of the air on the inner surface (3) of the container (2).

9. The method according to claim 6, wherein the suctioning of air comprises sucking the air from the sealable container (2) at a flow rate of 60-240 Nm per cubic meter of volume defined by the inner surface (3) of the sealable container (2). 3 / h.

10. The method of any one of claims 6 to 9, comprising sequentially activating jet nozzles of the plurality of jet nozzles such that the feed of air provides a time-varying air flow through the jet nozzles.

11. The method according to any one of claims 6 to 9, wherein the feeding of air comprises changing the air flow through at least one of the plurality of jet nozzles to temporarily increase the air flow through the at least one jet nozzle and release powder from the inner surface (3).

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