Brewery drum

Description

[0001] The present invention relates to a mixer with a rotating mixing vessel and its use in beer brewing or ice extraction from plants and plant parts such as trichomes. State of the art

[0002] Beer production essentially consists of the following steps: malting (germinating barley to activate enzymes that hydrolyze starch), kilning (roasting the germinated barley to produce malt, among other things to develop flavor compounds), milling the malt to the desired grist size, mashing (heating the roasted malt in an aqueous suspension to hydrolyze starch into fermentable sugars, thus obtaining the wort), lautering (separating the wort from the malt), wort boiling (to add bittering compounds along with hops), raking (removing the hops and proteins that precipitate during boiling from the wort), and fermentation. Mashing is the step that determines the proportion of fermentable sugars and thus the maximum possible alcohol content of the finished beer.During mashing, a thorough mixing of the malt with the aqueous phase is desirable to extract as much sugar as possible, which requires more intensive mixing. On the other hand, it is undesirable for the malt to be crushed during mashing, because such fine particles make lautering more difficult. This necessitates a gentler mixing process.

[0003] Depending on the size of the brewery, these steps are carried out in separate vessels. The largest breweries are designed as four-vessel brewhouses, with a mash tun, a mash kettle, a lauter tun, and a wort kettle, often stacked on top of each other to allow for pumpless transfer of liquids from one vessel to the next. While having four separate vessels for each of the four steps allows all four steps to be carried out simultaneously on different batches of brewing, it requires the most space and construction effort.

[0004] Three-vessel brewhouses are more compact, typically using the same vessel as both mash tun and wort kettle, while the other two vessels serve as the mash tun and lauter tun. Even more compact are two-vessel brewhouses, where one vessel typically acts as both mash tun and wort kettle, and a second vessel typically serves as both mash tun and lauter tun. The most compact design, but typically also the one with the smallest capacity (ideal for homebrewers), is the single-vessel brewhouse, where a single vessel performs all four functions.

[0005] In general, brewing capacity tends to increase with the number of vessels operating simultaneously side by side in different functions; on the other hand, the space requirement increases with the increasing number of vessels.

[0006] Ultrasound has already been used in malting, see US 2,745,789 A. The function of the ultrasound was to accelerate the water absorption of the barley and its germination.

[0007] DE 101 56 829 A1 and CN 201395585Y describe the use of ultrasound in mashing, using conventional fixed mash pans; CN 201395585Y additionally uses a propeller stirrer attached to the bottom of the mash pan.

[0008] Ultrasound has also been used in wort boiling with hops, see US 2,816,031 A. There, the use of ultrasound is intended to enable the colloidal dispersion of the hop resins and thus better extraction of the bitter substances. DE 297 13 506 U1 describes wort boiling or mashing using ultrasonic transducers.

[0009] GB 18237 (1913) describes in Fig. 1 and 2A lautering process in which the wort is separated from the mash by means of a perforated rotary drum. DE-PS-826 742 also describes a lautering process using a "rotary filter" that separates mash into spent grain and wort. FR-A-2 440 771 A1 discloses a rotary mixer with a bearing that is in Fig. 1 The left side is shown. At the right end, the rotary mixer rests on a roller 6.

[0010] The use of hydrodynamic cavitation during mashing is also known. For example, the Journal of Cleaner Production, 142(4), pp. 1457-1470 (2017) describes the use of a loop reactor with a Venturi nozzle in the loop during mashing. The Venturi nozzle generates hydrodynamic cavitation, which is intended to improve the extraction of starch and sugar from the malt. However, it proves difficult to apply this method in larger volumes. Furthermore, the grain is severely damaged, leading to further disadvantages during lautering.

[0011] In many extraction processes, including mashing, the presence of oxygen can be problematic because it can damage the substances being extracted or, specifically during mashing, the enzymes, flavor compounds, and / or ascorbic acid, which is crucial for the beer's flavor and stability. While heating reduces the solubility of oxygen in the extraction medium to around 4-5 ppm at typical mashing temperatures, the reactivity of this residual oxygen increases with rising temperature. Therefore, the typical target residual oxygen concentration during mashing is 0.5 ppm or less. Oxygen is usually removed by degassing the extraction medium and / or by exposure to a protective gas (nitrogen, carbon dioxide).

[0012] The object of the present invention is to provide a mixer that is particularly suitable for use in beer production and takes into account the aforementioned problems in mixing, enabling simpler process control with high throughput. Summary of the invention

[0013] The problem is solved according to the invention by a mixer as defined in claim 1.

[0014] Preferred aspects of the mixer and its application will be set out in the dependent claims and the following description. Detailed description of the invention

[0015] The mixer according to the invention generates acoustic cavitation through ultrasound. While the use of ultrasound in mashing was previously known (see above), to the applicant's knowledge, no such processes had yet been successfully carried out on a larger scale. The present invention makes this possible and reduces the aforementioned damage to the grain and the associated problems during lautering. The mixer according to the invention ensures more uniform ultrasound exposure than comparable previously known mixers.

[0016] The mixing container comprises an internal volume that accommodates the material to be mixed. The "internal volume" of the mixing container is understood to be the entire volume enclosed by the inner surface of the mixing container, including all internal elements such as a shaft or axle, any additional mixing tools (see below), and struts (see below).

[0017] The mixing vessel preferably has one or more openings, each of which can be sealed liquid-tight and / or gas-tight by an associated closure. "Liquid-tight" preferably means that the opening sealed by its associated closure is watertight up to the maximum overpressure occurring inside the mixing vessel during operation relative to the surroundings and at room temperature (approx. 23°C). "Gas-tight" preferably means that the opening sealed by its associated closure is airtight up to the maximum overpressure occurring inside the mixing vessel during operation relative to the surroundings and at room temperature (approx. 23°C).

[0018] The size and shape of the internal volume are defined by the mixing container when one or more openings are closed by their closures; however, these definitions remain valid and applicable even if the closures are open or removed: The volume limitations physically contributed by the closure(s) in the closed state remain identical as imaginary limitations after opening and, if applicable, removing the closure(s).

[0019] For the purposes of the invention, the internal volume of the mixing container can be determined, for example, by first closing all openings of the mixing container except for one ("all openings" means all openings that can be closed by means of a closure and the openings of the two bearings); wherein openings that can be sealed liquid-tight by means of a closure are closed with this closure, and openings of the bearings are closed by means of a plug; orienting the mixing container such that the one unsealed opening points upwards; completely filling the mixing container through the one open opening with a liquid of known density;Closing one open opening by means of its liquid-tight closure, or, if the one open opening was that of one of the two bearings, with a stopper, in such a way that any excess liquid is displaced from the opening during closing, thereby obtaining a gas-free and completely liquid-filled mixing vessel; weighing the gross weight of this liquid-filled, closed mixing vessel; completely emptying the liquid from the mixing vessel; reweighing the tare weight of the empty vessel and the liquid-tight closures and the two stoppers, and calculating the internal volume as the difference between the gross and tare weights, divided by the density of the liquid.

[0020] The internal volume of the mixing vessel, which can be determined in this way, depends on the specific application of the mixer according to the invention. In a preferred embodiment, particularly when the mixer according to the invention is used in brewing, this internal volume is preferably in the range of 1 liter to 30 cubic meters. More preferably, this internal volume is then in the range of 1 to 500 liters or in the range of 5 to 20 cubic meters.

[0021] In the context of this application, the term "mixture" with which the mixer according to the invention can be filled is understood to mean a mixture comprising a liquid or gas component and a particulate solid component. The liquid or gas can function as an extraction medium for the particulate solid. Suitable liquids include, in particular, water, aqueous solutions, or mixtures of water and a solvent miscible with water in any proportion, such as C1-C3 alcohols, acetone, oils, tetrahydrofuran, or supercritical gases like supercritical CO2, supercritical ethane, or supercritical propane. Suitable gases include, for example, subcritical CO2 or ammonia. The preferred liquid is water.Suitable particulate solids include, in particular, ground, crushed, or ground biomass, especially grains, seeds, kernels, whole plants, plant parts such as trichomes, berries, fruits, blossoms, or wood chips; the particulate solid may, in addition to the aforementioned grinding, crushing, or grinding, have undergone further pretreatments, such as thermal pretreatments for drying and / or roasting. The particle size of the particulate solid is preferably such that it passes through sieve No. 1 and is filtered out by sieve No. 5 when the sieves of the Pfungstadt Plansifter are used. The weight ratio between liquid and particulate solid in such a mixture is preferably in the range of 10:1 to 1:2.

[0022] A preferred example of a mixture with which the mixing vessel of the mixer according to the invention can be filled comprises barley malt and water, and is preferably suitable for mashing in beer brewing.

[0023] The mixing container is preferably filled with the mixture in such a way that the internal volume of the mixing container is filled to at least 95%, more preferably to at least 99%.

[0024] The term "approximately", when used together with a numerical value, preferably means in the context of this application that a deviation of ±10% from that numerical value is permitted or possible. In particular, when used in connection with a lower limit of a range, "approximately" preferably means that this lower limit of a range may be undercut by up to 10%, and when used in connection with an upper limit of a range, preferably means that this upper limit of a range may be exceeded by up to 10%.

[0025] The mixing vessel in the mixer according to the invention is preferably made of a stainless steel approved for food applications, for example AISI 316 (material number 1.4404) or AISI 304 or AISI 304L (material numbers 1.4301, 1.4306 or 1.4307), of copper, or of copper-coated steel. If the mixer according to the invention includes a heating element (see below), copper or copper-coated steel is preferred with regard to optimized heat conduction.

[0026] The mixer according to the invention functions largely or even exclusively as a free-fall mixer with regard to the mechanical, gentle mixing of malt and liquid, due to its rotating mixing vessel. Surprisingly, it was found that, at the typical malt-to-water ratios for mash, i.e., in the range of 1:2.5 to 1:5 parts by weight, the mechanical, gentle mixing according to the free-fall mixer principle works satisfactorily with regard to maximum sugar extraction and minimal damage to the mixture / grain, and this is true for all grist sizes commonly used in beer production.

[0027] Due to its primary or exclusive operation as a free-fall mixer, the axis of rotation of the mixing vessel preferably deviates from the horizontal by no more than 20°. More preferably, the axis of rotation deviates from the horizontal by no more than 10°, and even more preferably by no more than 5°. Particularly preferably, the axis of rotation is exactly horizontal.

[0028] For example, the principal axis of inertia of the mixing container with the lowest principal moment of inertia is suitable as the axis of rotation for the mixing container capable of rotation in all its embodiments.

[0029] To enable the rotation of the mixing container, it is rotatably mounted at the two points where the axis of rotation passes through the mixing container, or it rests on rollers or a gear with a guide rail.

[0030] In a first embodiment, the mixing container is enabled to rotate (this rotation is not part of the invention) by means of two cylindrical pins attached to the mixing container, the central axis of which lies on the axis of rotation and which are rotatably mounted on or in bearings arranged outside the mixing container. This embodiment is particularly preferred if the mixing container is to be designed as a pressure vessel.

[0031] In a second embodiment for enabling rotation, which is not part of the invention, the mixing container is enabled to rotate by means of an axle or shaft extending along the axis of rotation and rigidly connected to the mixing container. This rigidly connected axle or shaft typically has two extensions similar to the pins mentioned above, which in turn are supported on two bearings outside the mixing container.

[0032] To enable rotation, the mixing container according to the invention is enabled to rotate by means of an axis that is freely rotatable relative to the mixing container, in particular a rigid axis, and which runs along the axis of rotation of the mixing container. In this case, the mixing container itself has two bearings by means of which the mixing container is freely rotatable relative to the rigid axis. The axis is then supported outside the mixing container. This axis runs through the entire mixing container. Alternatively, it is in the form of two axis sections that are freely rotatable relative to the mixing container, in particular rigid axis sections, which run along the axis of rotation of the mixing container, but not along the entire length of the mixing container. These axis sections each project into one of the two bearings of the mixing container, and the mixing container would be rotatably mounted on these two axis sections.

[0033] In the case not according to the invention, where an axle or shaft is firmly connected to the mixing container and runs through the entire mixing container, struts can extend radially from this axle or shaft, extending to the inner surface of the mixing container and being attached to it, thus providing additional rigidity of the mixing container and additional mechanical stirring action.

[0034] The mixing vessel is preferably rotationally symmetrical about an axis of symmetry when viewed from the outside; more preferably, it has a cylindrical outer surface and a first and a second end face, which are also preferably rotationally symmetrical about the same axis of symmetry; more preferably, both end faces are planar or have a convex curvature, i.e., they then have the shape of a spherical cap or a cap cut from a revolution ellipsoid. For the purpose of cleaning the mixing vessel, preferably at least one of these two end faces can be removable, for example, by being screwed to the mixing vessel in a liquid-tight and (if the mixture contains a gas) gas-tight manner.

[0035] In the case of a mixing container that is rotationally symmetrical from the outside, or a mixing container with a cylindrical surface, in a first preferred symmetry variant the axis of symmetry can coincide with the axis of rotation, because the axis of symmetry is then generally the principal axis of inertia with the smallest moment of inertia. The two points where the axis of rotation intersects the mixing container are then located at the center of the end faces, which are also preferably present.

[0036] In a second preferred symmetry variant, in the case of a mixing vessel that is rotationally symmetrical from the outside or a mixing vessel with a cylindrical surface, the axis of symmetry can be inclined relative to the axis of rotation, so that the rotation simultaneously acquires a wobble component. In this case, the two points where the axis of rotation intersects the vessel are not exactly at the center of the two end faces, which are also preferably present, but somewhat eccentric to them. On one end face, the intersection point is offset in one direction from its center by a certain distance, and on the other end face, it is offset in the opposite direction from its center, preferably by the same distance. In such a mixer with a wobble component, the intersection point between the axis of symmetry and the axis of rotation preferably lies on the axis of symmetry approximately halfway between the two points where the axis of symmetry intersects the inner surface of the mixing vessel.

[0037] In a third preferred symmetry variant, in the case of a mixing container that is rotationally symmetrical from the outside or a mixing container with a cylindrical surface, the axis of rotation can indeed run parallel to the axis of symmetry, but be offset from it by a certain distance. In this case, the two points where the axis of rotation intersects the axis are again not exactly at the center of the two end faces, which are also preferably present, but also slightly eccentric to them. However, on both end faces, they are offset from the center in the same direction and preferably by the same distance to ensure the parallelism between the axis of symmetry and the axis of rotation.

[0038] In one embodiment of the drive, which is not part of the invention, the mixing container can be set in rotation by a torque acting via its axis of rotation. For this purpose, the mixing container has either two pins (according to the first embodiment of the rotation capability described above) or a shaft rigidly connected to the mixing container (according to the second embodiment of the rotation capability described above). This form of torque transmission is possible for all mixing containers and is preferred for asymmetrical mixing containers. Torque transmission via the shaft is particularly preferred in the case of a rotationally symmetrical mixer viewed from the outside, or a mixer with a cylindrical surface, if the axis of symmetry is inclined relative to the axis of rotation or offset parallel to it (see above).

[0039] In the inventive embodiment of the drive, the mixing container is set into rotation by a torque acting directly on its outer surface. In this embodiment, the torque from a drive motor can be transmitted externally to the outer surface of the mixing container by means of rollers or cylinders. For this purpose, the rolling surfaces of these rollers or cylinders are preferably coated with a material that has a high coefficient of static friction with the outer surface of the mixing container, such as a rubber coating. If the mixing container is heatable (see below), this rubber coating is then preferably made of heat-resistant silicone rubber.In this first variant of external torque transmission, these rollers or cylinders preferably run along the underside of the mixing container and along its entire length; in this case, the mixing container has a cylindrical outer shape. When the rollers or cylinders run along the underside and along the entire length of the cylindrical mixing container, not only is the torque transmitted, but additional support for the mixing container is also provided. In a second variant of external torque transmission, a transmission belt is provided that acts on the outer surface of the mixing container. In a third variant of external torque transmission, the outer surface of the mixing container can have an annular toothed ring that engages with a gear mounted on the drive motor, thus transmitting the torque from the drive motor to the mixing container.In this third torque transmission variant, the outer surface of the mixing container is rotationally symmetrical at least at the point where the toothed ring is attached.

[0040] In all embodiments of the mixer according to the invention, which has a cylindrical outer surface, rollers can be provided along the entire length of the outer surface and on its underside, as described above in the first variant of external torque transmission. These rollers do not transmit torque but merely rest on the outer surface of the mixing container and rotate passively, thereby supporting the mixing container from below.

[0041] In all embodiments of the drive and all variants of the torque transmission, a gearbox can be interposed that reduces the initial (usually presumably too high) speed of the drive motor.

[0042] The drive motor and torque transmission to the mixing container are preferably designed in such a way that the mixing container, when filled with the mixture, is capable of rotating at speeds of 1 to 15 rpm.

[0043] In a first preferred embodiment of the mixing process, mechanical mixing is achieved by lifting the material to be mixed solely through friction against the inner wall of the mixing container, after which it falls freely through the mixing chamber due to its own gravity. In this first preferred embodiment, no additional mixing tools such as paddles, knobs, or shafts are attached to the inner surface of the mixing container; the inner surface of the mixing container is therefore smooth.

[0044] In a second preferred embodiment of the mixing system, the inner surface of the mixing container has irregularities that facilitate the lifting of the mixture contained within. These irregularities can take the form of a profile on the inner surface, such as knobs or ridges. If ridges are used, they can either run approximately parallel to the direction of rotation of the mixing container, or they can spiral clockwise or counterclockwise along the inner surface of the mixing container. In the latter case, clockwise and counterclockwise ridges can be combined in equal proportions and with the same design. These ridges can extend along the entire inner surface of the mixing container, or they can be designed as segments, each extending only along a portion of the inner surface.The irregularities can also be designed as actual mixing tools, for example in the form of shovels, deflectors or stirring rods.

[0045] The mixer according to the invention comprises at least one ultrasonic source capable of sonicating at least a portion of the internal volume of the mixing vessel, preferably its entire internal volume. If the mixture comprises a liquid, this sonicated portion of the internal volume is preferably the portion that is filled with and / or comes into contact with the mixture. The at least one ultrasonic source is arranged inside the mixing vessel. The one or more ultrasonic sources are, on the one hand, one or more ultrasonic transducers mounted inside the mixing vessel. Such immersion transducers in the form of transducers are known per se.These are plates made of a highly ultrasound-conductive material, in particular metal, preferably a food-grade stainless steel as exemplified above, on which electromechanical or piezoelectric converters are mounted in a two-dimensional grid, preferably a square grid. These converters generate the ultrasound in phase and transmit it to the vibrating plate. The ultrasonic vibrating plate acts as an ultrasonic resonator and therefore has a resonant frequency corresponding to the frequency of the ultrasound generated by the converters, and preferably a thickness corresponding to half the wavelength of the ultrasound to be generated. These internally mounted ultrasonic vibrating plates can preferably be positioned perpendicular to the axis of rotation of the mixing vessel, so that their surface normal is parallel to the axis of rotation of the mixing vessel.In this case, they are round (especially circular) or angular (especially square). They are either attached to the inside of the mixing container or to a shaft rigidly connected to it (according to the second embodiment above, to enable rotation) or attached to a shaft running inside the mixing container that is free to rotate relative to it (according to the second embodiment above, to enable rotation). Such ultrasonic vibrating plates irradiate the interior of the mixing container (or part thereof) in such a way that the plane of vibration of the ultrasound is aligned with the axis of rotation.

[0046] Alternatively, or in addition to the vertically oriented ultrasonic vibrating plates described above, an ultrasonic vibrating plate (preferably exactly one) can be provided inside the mixing vessel such that the axis of rotation of the mixing vessel lies within this vibrating plate and the surface normal of this ultrasonic vibrating plate is perpendicular to the axis of rotation. This single vibrating plate with its surface normal perpendicular to the axis of rotation is preferably arranged such that its surface normal is inclined to the vertical, approximately at an angle of 20° to 40°. For the use of such an ultrasonic vibrating plate, it is preferred that the mixing vessel has a cylindrical interior and that this ultrasonic vibrating plate has a rectangular shape, such that the longer side extends in the direction of the axis of rotation and the shorter side is perpendicular to the axis of rotation.Such an ultrasonic vibrating plate irradiates the interior of the mixing container (or part thereof) in such a way that the plane of vibration of the ultrasound runs perpendicular to the axis of rotation.

[0047] If this vibrating plate with surface normal perpendicular to the axis of rotation is present, whether alone or in combination with the vibrating plates with surface normal parallel to the axis of rotation discussed above, it is preferably attached to an axis running inside the mixing container, which is freely rotatable relative to the mixing container, in particular a rigid axis (according to the third embodiment above to enable rotation).

[0048] On the other hand, the ultrasound source has the form of a box profile or a square tube, which runs longitudinally, in particular, inside the mixing vessel and which has one or more ultrasound generators inside the box profile or square tube, which serve to sonicate the area around the box profile or square tube; that is, the direction of sound propagation from each ultrasound generator contained therein is from the inside of the box profile or square tube outwards. Before installation in a device according to the invention, such an ultrasound source is open at both ends of the box profile or square tube; after installation in the device according to the invention, the box profile or square tube is sealed at least liquid-tight at both ends, since the ultrasound generators are not to be directly exposed to the mixture, which generally consists of a liquid.Such a seal can be achieved during installation in the mixing container by means of the end faces of the mixing container and / or by axial sections of the mixing container and / or by profile end plates that close both end faces of the box section or square tube. The seal, which is at least liquid-tight, is designed in such a way that the power supply to the ultrasonic generators located inside the box section or square tube is maintained via suitable cables or wires. To the inventor's knowledge, such an ultrasonic source in the form of a box section or square tube, which is either open at both end faces or sealed at least liquid-tight at both end faces, is novel and could also be part of the invention.The closest known ultrasound sources of similar design are already known in the field of ultrasonic baths for cleaning; however, in these applications, the ultrasound sources are attached to the outside of the box profile or square tube and serve to sound through its interior, i.e., the direction of sound propagation of each attached ultrasound generator is from the outside to the inside.

[0049] An ultrasonic vibrating plate designed, oriented, and mounted in this manner, with surface normals perpendicular to the axis of rotation, or an ultrasonic source in the form of a box profile or a square tube running longitudinally inside the mixing vessel, causes the mixture to be simultaneously and evenly mixed and exposed to acoustic cavitation within the interior during the rotating operation of the mixing vessel. This occurs because the particulate solids of the mixture fall or float at the ultrasonic source(s). Furthermore, the mixture, lifted by the inner wall of the mixing vessel, can fall onto this ultrasonic vibrating plate and run or trickle down it, thereby being simultaneously irradiated with ultrasound. This significantly increases the extraction effect of the liquid or gas in the mixture on the particulate solids.

[0050] The frequency of the ultrasound generated by the ultrasound source(s) is preferably in the range of 20 to 100 kHz, more preferably 25 to 80 kHz. In a more preferred embodiment, the frequency of the ultrasound is swept, i.e., it varies over time, particularly periodically, between a minimum and a maximum frequency. It is known from prior hydrodynamic cavitation methods that a high density of cavitation bubbles with low thickness, i.e., those generated at a high frequency, produces the best effect. According to the invention, this can be achieved analogously with acoustic cavitation.

[0051] Four embodiments are disclosed for the combination of ultrasonic sources arranged inside the mixing container, their power supply and the torque transmission required for rotation of the mixing container.

[0052] The first combined embodiment according to the invention includes the first preferred symmetry variant described above, the embodiment described above for enabling the rotation of the mixing vessel, the transmission of torque to the mixing vessel is effected according to one of the three torque transmission variants exemplified above from the outside, and the ultrasonic source(s) is / are attached to the rigid axis and is / are therefore also rigid. The ultrasonic sources are powered via the rigid axis, which has suitable electrical conductors for this purpose. Optionally, this axis can also be hollow internally and have perforations to allow pressure equalization and / or the supply or drainage of liquid (see below).

[0053] The second, non-inventive combined embodiment comprises the first preferred symmetry variant described above, the second, non-inventive embodiment described above for enabling the rotation of the mixing container with a fixedly connected axle, the transmission of torque is effected according to one of the three torque transmission variants exemplified above from the outside, and the ultrasonic source(s) is / are attached to the axle and therefore rotates with the axle and the mixing container. To ensure the power supply to the ultrasonic sources, two slip rings, which are common in the art, can be attached to the outside of the mixing container, interacting with stationary brushes, in particular carbon brushes, that graze over the slip rings, thus enabling the transfer of electric current from a static voltage source to the rotating mixing container.From each of the two slip rings, an insulated electrical conductor leads through an opening in the outer shell of the mixing vessel into its interior and to the ultrasonic sources, in particular ultrasonic transducers, mounted on the shaft. Alternatively, only one slip ring / brush pair can be mounted on the outside of the mixing vessel, with an insulated cable leading into the interior of the mixing vessel as described above; a second slip ring is mounted on the shaft and interacts with a second brush there. The current transmitted to the shaft can be carried to the ultrasonic sources via an insulated electrical conductor. Alternatively, two mutually insulated slip rings can be mounted on the shaft, each interacting with a corresponding brush. In this case, the shaft provides the complete power supply to the ultrasonic sources via two insulated electrical conductors.If desired, this axis can also be hollow inside and have perforations to allow pressure equalization and / or the supply or drainage of fluid (see below).

[0054] The third, non-inventive combined embodiment comprises the first preferred symmetry variant described above, the second, non-inventive embodiment described above for enabling the rotation of the mixing container with a rigidly connected shaft, the transmission of torque according to the first embodiment described above via the axis of rotation, and the ultrasonic source(s) is / are attached to the shaft and therefore rotates with the shaft and the mixing container. The power supply to the ultrasonic source(s) is the same as in the second preferred combined embodiment described above, with the proviso that all references to the "axis" are replaced by references to the "shaft".

[0055] The fourth combined embodiment according to the invention comprises the first preferred symmetry variant described above; the ability to rotate the mixing container according to the invention, with two rigid axle sections freely rotatable relative to the mixing container and projecting into the two bearings of the mixing container; the transmission of torque according to the second embodiment described above is from the outside to the outer surface of the mixing container; and the ultrasonic source(s) is / are connected to the two rigid axle sections. The power supply to the ultrasonic source(s) is the same as in the first combined embodiment described above, with the proviso that all references to the "rigid axle" are replaced by references to one of the two "rigid axle sections".

[0056] In a first embodiment of the temperature control system, the mixer according to the invention does not include a heating element. If used in this form in a brewery, it would be suitable, for example, for mashing using infusion or decoction methods. The heat required for these methods could nevertheless be supplied by means of separately heated water or a separate, separately heated portion of the mash. This first embodiment is also suitable for extraction processes under cooling, in which the mixture is either cooled internally with the additional addition of ice (see below) or cooled externally using refrigeration units and external cooling coils.

[0057] In a second embodiment of the temperature control system, the mixer according to the invention includes a heating element arranged outside the mixing vessel. This external heating element can be an induction, gas, or steam heater, particularly if the mixing vessel is made of metal as exemplified above. In the case of induction heating, the mixing vessel could typically be wrapped with a coil that generates the alternating magnetic field required for the induction heating of the (then necessarily electrically conductive) mixing vessel. Also in the case of induction heating, the mixing vessel (which can then be electrically conductive or electrically insulating) could preferably be additionally filled during operation with susceptors in the form of electrically conductive, particularly metallic, shaped bodies, especially in the form of spheres. These would also be inductively heated and would ensure more uniform heating of the mixture.These susceptors could advantageously also be hollow in order to have a density such that they float in the mixture as much as possible by means of buoyancy, thus avoiding a grinding effect on the mixture and the particulate solid contained therein as much as possible.

[0058] While it is possible for a heater located outside the mixing tank to heat the entire tank, it is not necessary. A permanently installed external heater that heats only a portion of the mixing tank (i.e., specifically, only a portion of the outer surface of the mixing tank) is sufficient.Given a selected and specified mixing vessel, heating geometry, number of heating elements, thermal power of the heating element, and distance between the heating element and the outer surface of the mixing vessel, this "heated" area is bounded and defined by a closed curve on the outer surface of the mixing vessel, as follows: Any two points on this closed curve that simultaneously lie on a cross-section through the mixing vessel perpendicular to the axis of rotation are defined as the two locations where, during heating, the temperature measured on the outer surface of the mixing vessel is no more than 5° Celsius above the constant or maintained ambient temperature (i.e., room temperature, approximately 23°C), with the measurements being carried out with the mixing vessel at rest, empty, and in thermal equilibrium.To determine this "heated" part of the outer surface, all cross-sections through the mixing vessel are considered where the two points are separated by a temperature difference of no more than 5°C. Cross-sections where only one such point is visible (i.e., where the two points coincide) are considered the boundary of this "heated" part of the outer surface in the direction of the axis of rotation.

[0059] Preferably, for a given mixing vessel, the external heating, the geometry of the heating, the heating power, and the distance between the heating and the outer surface of the mixing vessel are selected such that the "heated" part of the outer surface, as defined and determined above, is such that at every possible cross-section through the mixing vessel as defined above, the two points mentioned above, with a temperature difference of at most 5°, when each is connected to the axis of rotation by an imaginary line that runs perpendicular and radial to the axis of rotation, together with and between these imaginary lines, enclose an angle of at most 30°, regardless of the rotational position of the mixing vessel with respect to the heating.

[0060] In a third embodiment of the temperature control system, the mixing vessel includes an internal heating element. This is typically an electric heating element in the form of one or more ohmic heating elements, such as rods. These ohmic heating elements are made of a material that is electrically conductive but also has a sufficiently high ohmic resistance to heat up when current flows through them. The preferred material for these ohmic heating elements is graphite. The heating elements may include an electrically insulating, heat-resistant coating, for example, made of a ceramic material.

[0061] These internal heating elements can be rigid, meaning they do not rotate with the mixing container. For this purpose, they are typically attached to the rigid axis running inside the mixing container or to two rigid axis sections that are freely rotatable relative to the mixing container and project into bearings within the mixing container. Alternatively, they can be attached to a rigid ultrasonic source, which is itself attached to the rigid axis or rigid axis sections running inside the mixing container and that are freely rotatable relative to the mixing container. In this first case of rigid internal heating elements, the embodiment described above, enabling rotation with only two axis sections projecting into the two bearings of the mixing container, is particularly preferred.The mixing vessel is then preferably set into rotation by means of the second embodiment described above to apply the torque from the outside, and the mixing vessel then preferably has a cylindrical outer surface. The ultrasonic sources are preferably in the form of rigid box sections or square tubes containing ultrasonic generators. These rigid heating elements are preferably powered via lines or cables that pass through the axial sections and into the heating elements.

[0062] On the other hand, the heating elements arranged inside the mixing vessel can be attached to the mixing vessel and rotate with it. In this second case, where the heating elements rotate with the mixing vessel, each of the embodiments disclosed above is possible for enabling rotation, and each of the embodiments above is possible for applying torque. The ultrasonic sources are preferably in the form of ultrasonic vibrating plates with surface normals parallel to the axis of rotation. These plates can be provided with suitable openings through which the axial heating elements pass without touching the ultrasonic vibrating plates and thus avoiding their damping. In the case of rectangular ultrasonic vibrating plates, these heating elements would typically run in the recesses located between the inner wall of the mixing vessel and the edges of the rectangular ultrasonic vibrating plates.The power supply for these heating elements, which are connected to the end faces or the inner surface of the mixing container, is preferably via slip rings that are attached to the outside of the mixing container and interact with stationary brushes (see above).

[0063] In a fourth embodiment of the temperature control system, the mixing vessel can include an internal cooling system. This can be a cooling element similar to a cooling coil in a cooling slender or a heat exchanger. In both cases, the coolant supply and discharge can be effected via cooling lines that enter the mixing vessel through two rigid, rotatable axle sections that project into the two bearings of the mixing vessel. This cooling system is then typically rigidly connected to the two axle sections. According to the second embodiment described above, the torque is transmitted externally to the outer surface of the mixing vessel; and the ultrasonic source(s) is / are also connected to the two rigid axle sections.The power supply of the ultrasound source(s) is the same as in the preceding first combined embodiment according to the invention, with the proviso that all references to the "rigid axis" are replaced by references to one of the two "rigid axis sections".

[0064] In the case of a mixing vessel with a cylindrical shell surface and two end faces, these internal heating elements, particularly in the form of rods, would typically run axially over at least part of the length of the mixing vessel (e.g. over 70-95% of this length), or over the entire length of the mixing vessel from one end face of the mixing vessel to the other.

[0065] It is also preferred that, for a given mixing container, the external heating or the internal heating elements, the geometry of the heating or the heating elements, the heating power and the distance between the external heating and the outer surface of the mixing container are selected such that the internal volume of the mixing container, when filled with mixture and rotating, can be heated to an internal temperature of about 90° Celsius, or up to 80° Celsius.

[0066] In the preferred heated form, an overpressure can be created inside the mixing container of the mixer according to the invention during heating.

[0067] In a first embodiment, the mixing vessel for pressure equalization has a rigid axis, freely rotatable relative to the mixing vessel, as described in the third preferred embodiment above, enabling rotation. This axis supports the ultrasonic sources, in particular ultrasonic vibrating plates. For this first embodiment of pressure equalization, the first embodiment combined according to the invention, comprising ultrasonic sources, in particular vibrating plates, arranged within the mixing vessel, their power supply, and the torque transmission required for rotation of the mixing vessel, is preferred. However, in this embodiment, the axis is additionally hollow, with its inner cavity being in liquid- and / or gas-conducting contact with the inner volume of the mixing vessel by means of perforations. These perforations are preferably circular and have a diameter sufficiently small to prevent particles of the particulate solid from passing through.This hollow shaft typically begins to fill with the liquid mixture as soon as the mixing vessel is filled with such mixture up to a level that is at least partially above the shaft. The hollow shaft extends out of the mixing vessel and is connected to a similarly hollow, open-topped riser pipe. This riser pipe can be a rigid, upward-pointing tube or a hose. It extends to a height sufficient to hold a column of liquid within it, such that its hydrostatic pressure equals the maximum permissible pressure inside the mixing vessel, and the fill level can be indicated, if necessary, in a sight glass. In this design, pressure equalization between the mixing vessel and the surrounding environment is possible via the hollow shaft and the riser pipe through fluid displacement.When the pressure in the mixing vessel increases, an additional portion of the liquid from the mixture is forced through the perforations in the shaft into the hollow shaft and into the riser pipe, causing the liquid level in the riser pipe to rise. This slightly increases the hydrostatic pressure in the riser pipe and, conversely, compensates for the rising internal pressure in the mixing vessel. If the internal pressure in the mixing vessel falls, liquid flows from the riser pipe back into the hollow shaft and through its perforations into the interior of the mixing vessel, causing the liquid level in the riser pipe to drop. This further reduces the hydrostatic pressure in the riser pipe and compensates for the falling internal pressure in the mixing vessel.Since the pressure fluctuations in the mixing vessel are slow and the fluid exchange between the mixing vessel and the reservoir is rapid, the system is always nearly in equilibrium, in which the hydrostatic pressure in the riser pipe is always equal to the pressure in the mixing vessel. For this second variant, the first preferred embodiment mentioned above is preferably used for the combination of ultrasonic sources arranged inside the mixing vessel, their power supply, and the transmission of the torque required for rotation of the mixing vessel, because no rotatable bearing is required between the shaft and the riser pipe.

[0068] In a second embodiment, the mixing vessel for pressure equalization also features a rigid axis, freely rotatable relative to the mixing vessel, as described above in the invention, wherein the axis supports the ultrasonic sources, in particular ultrasonic vibrating plates. For this second embodiment of pressure equalization, the first combined embodiment described above, comprising ultrasonic sources, in particular vibrating plates, arranged within the mixing vessel, their power supply, and the torque transmission required for rotation of the mixing vessel, is also preferred. However, in this embodiment, the axis is not continuous but interrupted at one point. One or more of the ultrasonic sources, in particular ultrasonic vibrating plates, can be mounted on each of the two segments of the interrupted axis.To further secure these sections of the axle, struts can be provided as described above. However, in this case, these struts rotatably encircle the axle section by means of an external bearing, thus simultaneously supporting this section against the inner wall of the mixing vessel and allowing it to rotate freely relative to this section. This additional support is particularly advantageous when the aforementioned interruption of the axle is located close to one of the two sections.

[0069] The axis of rotation passes through the mixing vessel at its points of penetration, resulting in a very short section of the axis (presumably without ultrasonic sources, particularly ultrasonic vibrating plates) and a long section of the axis (presumably with all ultrasonic sources, particularly ultrasonic vibrating plates), and this long section is additionally supported. One of the two sections of the axis is hollow and open at its end located within the mixing vessel, so that this section is in contact with the internal volume of the mixing vessel, allowing liquid and / or gas to pass through. This opening within the mixing vessel is preferably circular and has a diameter small enough to prevent particles of the particulate solid from passing through.This internally hollow section of the axle typically begins to fill with the liquid or gas of the mixture as soon as such mixture is poured into the mixing container up to a fill level that is at least partially above the axle. The shorter, internally hollow section of the axle extends out of the mixing container and is connected to a similarly hollow, open-topped riser pipe. The pressure equalization mechanism of this open-topped riser pipe is the same as in the second variant described above.

[0070] In a third variant, the mixing vessel can have a diaphragm at at least one point (e.g., at one of the closures) containing a gas-permeable but liquid-tight membrane. This diaphragm allows for gradual pressure equalization through the escape of gas, particularly oxygen, carbon dioxide, nitrogen, and / or argon, but not the escape of liquid. The diaphragm functions during the rotation of the mixing vessel due to its alternating immersion in the liquid (membrane sealed) and as it rises out of the liquid (membrane allowing pressure equalization through gas passage). During subsequent cooling, the diaphragm equalizes any negative pressure that may develop through the return of gas. Such gas-permeable but liquid-tight membranes are known. These are primarily membranes made of perfluorinated polymers, such as polytetrafluoroethylene.Due to their perfluorinated and therefore chemically inert state, such membranes are also approved for food use.

[0071] Due to the rotation of the mixing vessel, local overheating of the mixing vessel and / or any associated deterioration, inactivation, or denaturation of components present in the mixture and / or boiling delay are practically eliminated. In this embodiment with heating, the mixer according to the invention is suitable not only for the two mashing processes mentioned above but also for the boiler mashing process.

[0072] To ensure a desired temperature program during heating, the mixing vessel of this preferred embodiment preferably also has one or more temperature sensors, of which typically at least one is located near the inner surface of the mixing vessel, or even directly on its inner surface, and at least one is located near the axis of rotation, or even directly on the axis of rotation (i.e., directly on an axis running along the axis of rotation). The measurement signals can be transmitted via cables, similar to those exemplified above for the power supply of the ultrasonic sources, or wirelessly. The sensors can be powered by a battery or accumulator, or also via cables as exemplified above for the power supply of the ultrasonic sources.

[0073] In a preferred embodiment of the mixer according to the invention, a portion of its internal volume is separated from the rest of its internal volume by means of a grid that extends close to the inner surface of the mixing vessel; such that the passage of liquid from the rest of the internal volume into the separated portion of the internal volume is possible, but not the passage of particulate solids. The grid fulfills the function of a sieve during a step of filtering particulate solids from the liquid.

[0074] If the mixer according to the invention is to be used in beer production, the grid acts as a sieve for the malt, particularly during a lautering step, and is therefore preferably sufficiently fine-meshed to prevent the passage of malt particles even in the finest possible grist size customary for beer production. The mesh size of the grid is preferably in the range of 1.3 to 0.1 mm, which is the usual range for retaining husks or malt grist in the grist sizes customary for beer production. More preferably, the grid then has one of the following mesh sizes: Mesh size Preferred filterable solid from malt milling 1.25 mm husks 1 mm coarse semolina 0.5 mm Fine semolina 1 0.25 mm Fine semolina 2

[0075] Preferably, the sieve has a mesh size in the range of 0.1 to 0.25 mm in order to be able to filter out all of the above-mentioned solids of the malt at the same time.

[0076] The grid is preferably in the form of a perforated grid and is preferably also made of a metal, as exemplified above for the mixing container. The preceding references to "mesh sizes" are to be understood as references to the "hole diameters" of preferably approximately circular holes in the perforated grid.

[0077] The grid preferably separates only a small portion of the internal volume from the rest of the internal volume of the mixing container, more preferably 5-15% of this internal volume. This separated portion of the internal volume is defined on the one hand by the geometric outer surface of the grid and on the other hand by the area of ​​the internal surface of the mixing container adjacent to the separated portion of the internal volume, and is sealed by the seam connecting the edge of the grid to the internal surface of the mixing container.

[0078] In order to delimit a part of the internal volume as defined above from the rest of the internal volume, said geometric outer surface of the sieve is preferably curved such that on every imaginary line that points outwards perpendicularly and radially from the axis of rotation of the mixing vessel, a first distance between the axis of rotation and the point where this line intersects the geometric outer surface of the grid is at most 10% smaller than a second distance between the axis of rotation and the point where this line intersects the inner surface of the mixing vessel, wherein the percentage difference between the first and second distances is greatest for such imaginary lines that point from the axis of rotation to a center point or a center line of the sieve;for imaginary lines pointing from the axis of rotation to a point other than the center or the centerline of the grid, the percentage difference is smaller, and for imaginary lines pointing from the axis of rotation to said joint, it approaches or becomes zero. Preferably, this percentage difference decreases monotonically from those imaginary lines pointing to the center or centerline of the grid to those imaginary lines pointing to the joint. In a particularly preferred embodiment, where the mixing vessel has a cylindrical internal volume defined by an internal surface with a first radius of curvature, the grid has the form of a cylindrical segment whose geometric outer surface has a second radius of curvature larger than the first radius of curvature, in particular wherein the second radius of curvature is 1 to 10% larger than the first radius of curvature.

[0079] The grid can be permanently welded or bonded to the inner surface of the mixing container, so that the connection is a weld or an adhesive joint. Alternatively, particularly if the mixing container has a cylindrical internal volume and the grid is in the shape of a cylindrical segment, the grid can be interchangeably clamped in suitable holders attached to the inner surface.

[0080] For the purpose of filtration using the grid, the mixing vessel in this case has at least one closable opening that separates from the environment into the partitioned portion of its internal volume, which can be sealed liquid- and / or gas-tight by means of a closure, and which is capable of draining liquid from the partitioned portion of the internal volume. Conversely, the mixing vessel in this case also has at least one opening that leads from the environment into the remainder of the internal volume, which can be sealed liquid- and / or gas-tight by means of a closure, and which is capable of filling the mixture into this remainder of the internal volume and / or draining the mixture from this remainder of the internal volume.

[0081] The invention will now be described with reference to exemplary embodiments illustrated in the drawings. The drawings show: Fig. 1 a transparent perspective view of the mixing container of a mixer according to the invention; Fig. 2 a sectional view of the mixing container of the mixer according to the invention. Fig. 1 ; wherein the sectioning plane is perpendicular to its axis of rotation; Fig. 3 a transparent schematic side view of the mixing vessel of a mixer according to the invention; Fig. 4 various views of an embodiment of a mixer of the invention with a mixing vessel having an ultrasonic source in the form of a box profile or square tube; Fig. 5 show the results of four mashing trials under different conditions, in which a mixer according to the invention with construction according to Fig. 4 was used.

[0082] Fig. 1 and 2Figure 1 illustrates a preferred embodiment of the mixer 1 according to the invention with a rotationally symmetrical mixing container 2, in particular a mixing container 2 with a cylindrical outer surface 22. The mixing container 2 has an internal volume of approximately 15 m³. Fig. 1 Figure 1 shows a transparent representation of its mixing container 2. This mixing container 2 has a cylindrical outer shape and an axis 5 extending along its axis of rotation 4. In this embodiment, the axis 5 is freely rotatable relative to the mixing container and does not rotate with the mixing container 2; it is therefore rigid. The axis 5 passes through two bearings 81, 82, each of which is mounted in one of the two end faces 91, 92 of the cylindrical mixing container 2. In this embodiment, at least one of the two end faces 91, 92 is removable to simplify cleaning of the interior of the mixing container 2.

[0083] The mixing vessel 2 comprises four ultrasonic vibrating plates 31, 32, 33, 34 arranged inside it, which are attached only to the non-rotating axis 5. Three of these ultrasonic vibrating plates 31, 32, 33 are of the type described above, in which the surface normal runs parallel to the axis of rotation. The fourth ultrasonic vibrating plate 34 is of the rectangular type described above, in which the surface normal is inclined at an angle of approximately 20° to the vertical (indicated by dashed lines in the figure). In In this embodiment, the (not shown) ultrasonic generators on the vibrating plates 31, 32, 33, 34 are powered via the non-rotating axis 5. The total ultrasonic power of the three ultrasonic plates is approximately 29 kW; the direction of propagation of the ultrasound is approximately along the axis of rotation 4.

[0084] The mixing vessel 2 also includes five openings, each of which can be closed in a liquid- and / or gas-tight manner by means of a closure (two of the openings are provided with reference numerals 61,62 and the associated closures with reference numerals 71,72).

[0085] In this embodiment, the mixer according to the invention can be heated. This heating element is located in Fig. 2 indicated with reference numeral 11; in Fig. 1 Two associated temperature sensors 101, 102 are shown, which are arranged on the first end face 91 of the mixing vessel 2, the first of which, 101, is located near the inner surface 21 of the mixing vessel 2 and the second, 102, is located near the axis of rotation 4. Fig. 2 is a sectional view through the mixing container 2, where the section plane is parallel to and close to the vibrating plate 31, as shown in Fig. 1The process is shown. The mixing container 2 can be heated by means of a heater 11. The "heated" part of the outer surface, as defined in the general part of the description, is only visible here as its two points (black dots), which are simultaneously on the surface shown. Fig. 2The cross-section through the mixing container shown here lies at two points. From these two points, two dashed lines extend perpendicularly and radially to the axis of rotation 4, connecting the two points to this axis of rotation in such a way that the two points, together with the two lines and between these lines, enclose an angle of approximately 30°. These two points represent two points on the boundary line of the "heated" part of the outer surface of the mixing container, lying on the cross-section through the mixing container shown here. For any other cross-section that is offset from the cross-section shown here in the direction of the axis of rotation 4, two new points on this boundary line would result.

[0086] The in Fig. 1 and 2The illustrated embodiment is also equipped with a grid 12, which, if used in a brewery, would serve, among other things, to lauter the mash. This grid 12 separates a portion 13 of the internal volume of the mixing vessel 2, located close to its inner surface 21, from the rest of its internal volume. A liquid- and / or gas-tight opening 62 leads from the surroundings (it would be the same opening 62 as in Fig. 1) into this separated part 13 of the inner volume. The separated part 13 of the inner volume shown here corresponds to a preferred embodiment from the general part of the description: The said geometric outer surface 121 of the grid 12 is curved such that the distance measured between this outer surface 121 and the inner surface 21 of the mixing container 2 along any imaginary line pointing outwards perpendicularly and radially from the axis of rotation 4 of the mixing container 2 decreases monotonically from the center line of the grid (which would be located here at the position of the opening 62 and be perpendicular to the plane of the sheet) to the connecting seam 14 between the grid 12 and the inner surface 21 of the mixing container 2. Two exemplary dashed lines are shown.In the first line, which runs closer to opening 62, this distance is indicated by two black dots; it is approximately 10%–20% of the distance measured on this line between the axis of rotation 4 and the point where this line intersects the outer surface 21 of the mixing vessel (the lower of the two black dots). In the second line, which runs towards the connecting seam 14, this distance is exactly zero, which is represented by only one black dot.

[0087] In the embodiment of Fig. 1 and 2 The torque is transmitted to the outer surface 22 of the mixing container 2 by means of rollers or cylinders 151, 152 and 153, 154. Preferably, the cylinders run along the underside and along the entire length of the cylindrical mixing container 2.

[0088] The mixer according to this embodiment can also include mixing tools in the form of sills 161 or paddles 162 arranged on the inner surface 21 of the mixing container 2. In this embodiment, it can also include struts inside the mixing container 2 (one of four is provided with reference numeral 17) which are fixedly connected to the inner surface 21 of the mixing container 2 and rotatably mounted on the non-rotating axis 5. These struts can optionally also be, as shown in Fig. 2 As shown, the components pass through the grid 12 at a point of passage. These struts 17 provide internal static stiffening of the mixing vessel 2 and can simultaneously function as additional mixing tools.

[0089] Fig. 3Figure 1 shows a further embodiment of the mixer according to the invention. Here, it comprises a rigid shaft 5, which is hollow internally and has a plurality of perforations (one of which is designated with reference numeral 51). The perforations establish a connection between the internal volume of the mixing vessel 2 and the cavity in the shaft 5. The shaft 5 leads to an upwardly pointing riser pipe 18. The shaft 5 and the riser pipe 18 typically fill with liquid up to a certain fill level as the mixing vessel is filled with the mixture. The combination of the hollow shaft 5, its perforations 51, and the riser pipe 18 ensures pressure equalization by means of liquid exchange between the mixing vessel and the riser pipe during the rotating operation of the mixer, and in particular during the simultaneous heating of the mixture during mixing.This embodiment also preferably includes a heating element (not shown in the figure). Also shown are two rollers 153, 154 running along the underside of the mixing container 2 for driving the cylindrical mixing container 2. In the preferred case, as in . Fig. 2 As mentioned, rollers 153 and 154 would be combined into a single continuous roller running along the underside and the entire length of the cylindrical mixing container.

[0090] Fig. 4Figure 1 shows representations of a mixer according to the invention, namely as a sectional view (a), a perspective view (b), and a front view with the end face of the mixer removed (c). The mixing container 2 is shown with two inlet openings 61 and one outlet opening 62. The mixing container 2 is rotatably mounted on four rollers 153, 154, 155, 156. In the sectional view (a), the rotatable mounting of the mixing container 2 is shown by means of two rigid (descending hatched) axle sections 191, 192, which project into two (ascending hatched) bearings 81, 82. A seal 211, 212 provides at least a liquid-tight seal between the rigid and rotating parts. The mixing vessel 2 contains a rigid ultrasonic source 35 in the form of a box profile or a square tube, which runs axially along about 90% of the length of the mixing vessel 2 and is rigidly connected to the two rigid axial sections 191,192.This ultrasonic source 35 has eight ultrasonic generators inside (one is designated with reference numeral 23). The ultrasonic generators have their sound openings facing downwards and thus emit sound from the inside of the box profile or square tube outwards. The box profile or square tube is sealed at its end faces against the interior of the mixing vessel, at least liquid-tight, by means of profile end plates 241, 242 and by means of the axial sections 191, 192. The first axial section 191, proximal to the riser pipe 18, is hollow and has a perforation 51; it serves as a hollow axle 5 and, together with the riser pipe 18, provides the pressure equalization described in the general section. The second axial section 192, proximal to the power connection 26, is designed as a rotary feedthrough for the electrical cables or lines 251, 252.Fixedly connected to the ultrasound source 35, and therefore also rigid, is an internal heater 11 in the form of a ceramic heating element containing a graphite rod as an ohmic resistor. The power supply for the ultrasound generators 23 is ensured by the cable or line 251, and the power supply for the internal heater 11 by the cable or line 252. The perspective view (b) shows the drive principle with the four rollers 153, 154, 155, 156. Of these, roller 155 (see (a)) acts as the drive roller, which, via a motor with gearbox 27, transmits a torque to the outer surface 21 of the mixing vessel 2, thus setting it in rotation. The remaining rollers 153, 154, 156 rotate freely and support the mixing vessel 2 during its rotation. The riser pipe 18, which ensures pressure equalization, is shown again.Also shown is a control box 28, which contains the necessary control and drive electronics for controlling the ultrasonic sources 23 and the motor / gearbox 27. The motor is typically a synchronous motor, which, by means of a suitable number of poles and a suitable associated AC voltage for each pole, allows a freely selectable speed of the mixing vessel 2. Side view (c) illustrates the arrangement of the ultrasonic source 35, the internal heater 11, the sieve 12 for separating part of the internal volume of the mixing vessel, and four paddles (one is designated with reference numeral 161). The removed end face would have reference numeral 91. A closable opening 911 for emptying the mixing vessel, which would also be present in the removed end face 91, is shown with a dotted line.

[0091] The mixer according to the invention is suitable for all processing methods in which a particulate solid, as exemplified above, is to be extracted with a liquid, as exemplified above, whereby the particulate solid is thoroughly mixed with the liquid. The mixer according to the invention, through the combination of free-fall mixing and simultaneous sonication of the mixture with ultrasound, achieves a significantly faster extraction of the particulate solid with the liquid. A preferred application area of ​​the mixer according to the invention is in beer brewing.

[0092] An extraction process according to the invention (in particular mashing) is analogous to a corresponding prior art process, but in which a mixer according to the invention is used as the extraction vessel (i.e., in particular as a mash tun). The process parameters of the process according to the invention can be typically identical to those of the corresponding prior art process, except that the mixing vessel is simultaneously sonicated with ultrasound and rotated.

[0093] The extraction process according to the invention (in particular mashing) could also be analogous to any previously known corresponding extraction process that uses only ultrasound sonication but no rotation of the extraction vessel, whereas in this case the mixing vessel according to the invention, used as the extraction vessel, is simultaneously rotated. In such an extraction process according to the invention (in particular mashing), however, due to the synergy of ultrasound sonication and rotation of the mixing vessel, a rotation of the mixing vessel could initially be freely selected, preferably in the range of 5–50 rpm, more preferably 10–30 rpm, and with and at this selected rotation of the mixing vessel a) the duration of the extraction process is shortened compared to the previously known extraction process, while maintaining the same ultrasound frequency and power; and / or b) the ultrasound frequency is reduced compared to the previously known extraction process, while maintaining the same ultrasound power and duration; and / or c) the ultrasound power is reduced while maintaining the same ultrasound frequency and duration; that nevertheless, the same extraction rate from the particulate solid (i.e., from the malt during mashing) is achieved as with the corresponding previously known extraction method, or even a better extraction rate. Preferably, it is the above alternative b); the reduction of the ultrasonic frequency can mean a gentler extraction (avoidance of sonochemistry) and / or the use of simpler ultrasonic sources and / or a longer service life of the mixer according to the invention. The comparison of the extraction rates could be based on the extent and / or the speed of the extraction. In the case of a comparison between any previously known mashing with ultrasound only and mashing according to the invention with ultrasound and rotation of the mixing vessel, the comparison of the extraction rates would typically be based on the determination of the Plato grades.An "analogous" method according to the invention is understood here to be a method that, with regard to the essential process parameters, in particular the batch size (i.e., the quantity and type of particulate solid and liquid, i.e., in the case of mashing, the quantity and type of malt and the quantity and type of water) and the type of temperature program (i.e., in the case of mashing, the type and duration of the temperature rests observed), is the same as the aforementioned corresponding prior known method, which only uses ultrasound.

[0094] In all cases of the mashing process according to the invention, due to the combined sonication with ultrasound and rotation of the mixing vessel, the usual removal of oxygen, as described in the introduction, can be omitted.

[0095] In its most general form, without heating and without a grid built into the mixing vessel, it is particularly suitable for mashing using the decoction or infusion method. The mixer would typically take over the functions of the mash tun and mash kettle in this case.

[0096] In its first preferred embodiment, with heating but without the grid built into the mixing vessel, it is suitable for mashing using the kettle mashing method. The mixer would typically also perform the functions of the mash tun and mash kettle. Optionally, it could also be used for the preliminary kilning.

[0097] In its second preferred embodiment, with a grid built into the mixing vessel but without heating, it is suitable for the steps of mashing using the decoction or infusion method and lautering. The mixer would typically perform the functions of the mash tun, the mash kettle, and, if necessary, the lauter tun. Due to the built-in sieve, the remaining malt can be washed with sparge water, and the sparge water can be filtered off through the grid.

[0098] In its third, particularly preferred embodiment with a grid and heating element integrated into the mixing vessel, it is suitable for preliminary kilning, subsequent mashing using the kettle mashing method, and subsequent lautering. The mixer would typically also perform the functions of the mash tun, the mash kettle, and, if necessary, the lauter tun.

[0099] The following describes an exemplary brewing process using a mixer according to the above particularly preferred embodiment, wherein the mixer additionally includes a pressure equalization or level indicator with a riser pipe (as explained in the general description and as shown in Fig. 3 The mixer also includes three vibrating plates arranged in the mixing vessel; the combination of vibrating plates arranged inside the mixing vessel, their power supply, and the transmission of the torque required for rotation of the mixing vessel is described in the first preferred embodiment of the general part of the description.

[0100] Approximately 3000 kg of typical, kilned, and appropriately milled barley malt and approximately 9000 liters of water are poured into the stationary mixing vessel through an upward-facing opening, for example, opening 61, and this opening is sealed liquid- and / or gas-tight with a closure 71, such as a screw cap. All other openings that the mixing vessel 2 may have are already sealed liquid- and / or gas-tight with their respective closures or wing valves.

[0101] The mixing container with the mixture of malt and water contained therein is set into rotation around the axis of rotation at approximately 5 - 15 rpm by means of the rollers 161,162.

[0102] With the mixing vessel continuously rotating, the mixture is mashed in at 40-45°C and heated to a final temperature of 76-78°C, observing a protein rest at 50-55°C, a maltose rest at 63-65°C, and a saccharification rest at 73-74°C. An induction heater 11, which heats the metallic outer shell of the mixing vessel 2, is used for this purpose. The temperature gradients and rests are monitored by means of temperature sensors 161 and 162.

[0103] During the entire mashing process, the interior of the mixing vessel 2 is sonicated by means of the three vibrating plates 31,32,33 with ultrasound at a continuously adjustable power of approximately 10 - 50 W per ultrasound source, in particular per vibrating plate.

[0104] The entire mashing process takes approximately 2-8 hours, depending on the fill level. Due to pressure equalization via the perforation(s) 51, the internally hollow shaft 5, and the riser pipe 18, the overpressure in the mixing vessel never exceeds approximately 0.1 bar.

[0105] While still hot, the mixing vessel 2 is stopped so that its internal grid 12 points downwards. The opening 62, which leads from the surroundings into the portion 13 of the mixing vessel 2's internal volume separated by the grid 12, is opened. The mash is then strained through the grid and drained via the opening 62 into a lauter tun. The volume equalization for the draining mash can be achieved via the riser pipe 18, which now allows not only all of its contents to flow back into the mixing vessel 2, but also ambient air to flow in. If desired, one of the other openings leading into the un-separated portion of the mixing vessel 2's internal volume, such as the upward-facing opening 61, is also opened to provide additional pressure equalization.

[0106] The opening 62 and any further opening that provides additional pressure equalization are closed again with their associated closures.

[0107] The malt remaining in the mixing vessel is washed with one or two sparges, which are either preheated or heated directly in the mixing vessel 2 itself by means of the heater 11, while the sparges are separated by filtration through the grid 12 as already described for the mash.

[0108] The filtered mash and the sparge water are mixed with hops in a separate wort kettle and boiled down to about 15° Plato.

[0109] The resulting original wort is cooled, separated from the hop residue in a standard whirlpool, and fermented with the addition of yeast.

[0110] The presence of one or more ultrasonic sources also facilitates the cleaning of the mixing vessel. For cleaning, the remaining mixture, particularly any remaining particulate solids, is advantageously emptied from one of the openings in the mixing vessel (if the mixing vessel contains a grid, this would be an opening that leads into the rest of the internal volume of the mixing vessel). If the mixing vessel has a removable end panel (see above), this end panel can also be removed, and the remaining particulate solids emptied by tilting the mixing vessel. The mixing vessel is then filled with cleaning fluid, particularly clean water, and the opening or end panel is resealed. Rotation and ultrasonic stimulation efficiently clean the internal volume of the mixing vessel, especially the holes of any perforated grid contained within it.

[0111] Example 1: Mash trials with a mixer according to the invention using ultrasound and / or rotation of the mixing vessel

[0112] In all tests, a mixer with a design according to [standard / specification] was used. Fig. 4 used, but which additionally had a small lockable tap on the outer surface 22 of the mixing container 2, which was normally closed. a) Mashing with ultrasound and rotation of the mixing vessel (according to the invention)

[0113] 9.2 kg of malt (a mixture of 3.8 kg Pilsner and 5.4 kg light wheat) and 33 liters of ordinary tap water (pH 6.5) were poured into mixing vessel 2 through the upward-facing openings 61, and these openings were sealed liquid- and gas-tight. No conventional degassing or purging with a protective gas such as nitrogen or carbon dioxide was performed. Mixing vessel 2, containing the malt and water mixture, was set into rotation around its axis of rotation at 21 rpm by means of rollers 161 and 162. With the mixing vessel 2 continuously rotating, the mixture was first mashed at 40-45°C, then mashed again, observing a protein rest at 50-53°C for 15 min, a maltose rest at 64°C for 30 min, a saccharification rest at 73°C for 20 min, and a lautering rest at 76-77°C for 10 min. These five temperature rests are in Fig. 5 a)The x-axis is indicated by the numbers 1, 2, 3, 4, and 5 respectively. Throughout the entire mashing process, the interior of the mixing vessel 2 was irradiated by the ultrasonic source 35 with its eight ultrasonic generators 23, emitting ultrasound at 27 kHz and a total power of 400 watts.

[0114] The wort content was determined according to standard procedure every 5 minutes using samples of the mixture. For this purpose, while mixing vessel 2 was rotating, the small tap was opened (with the tap at the bottom) and a sample of the mixture was drained into a beaker. The tap was then closed again. (On the Y-axis of...) Fig. 5 a) The increase in wort volume during mashing, as measured in this way, is given in degrees Plato. b) Mashing with ultrasound and rotation of the mixing vessel (according to the invention)

[0115] The experiment according to a) above was repeated, except that the ultrasound frequency was 80 kHz. The five temperature intervals observed are in Fig. 5 b) again, the x-axis is represented by the numbers 1, 2, 3, 4, and 5 respectively; the y-axis by Fig. 5 b) The measured increase in wort volume during mashing is given in degrees Plato. c) Mashing without ultrasound, but with rotation of the mixing vessel (comparison)

[0116] The experiment according to a) above was repeated, except that no ultrasound was used. The five temperature intervals are in Fig. 5 c) again, the x-axis is represented by the numbers 1, 2, 3, 4, and 5 respectively; the y-axis by Fig. 5 c) The measured increase in wort volume during mashing is given in degrees Plato. d) Mashing with ultrasound, but without rotation of the mixing vessel (comparison)

[0117] The experiment according to b) above was repeated, except that no rotation of the mixing vessel was used. The five temperature intervals are in Fig. 5 d) again, the x-axis is represented by the numbers 1, 2, 3, 4, and 5 respectively; the y-axis by Fig. 5 d) The measured increase in wort volume during mashing is given in degrees Plato.

[0118] Experiments a)-d) show that the combination of ultrasound and rotation of the mixing vessel is synergistic compared to the use of ultrasound alone or rotation of the mixing vessel alone, particularly at the beginning of the Plato degree increase. Specifically, the comparison between a) and d) shows that ultrasound at 27 kHz in combination with rotation of the mixing vessel at 21 rpm is more effective than ultrasound at 80 kHz without rotation of the mixing vessel.

Claims

1. Mixer (1) comprising a mixing container (2) with an interior volume and which is capable of rotating about a rotation axis (4), wherein the mixer (1) also comprises at least one ultrasound source (31,32,33,34,35) which is capable of sonicating at least part of this interior volume with ultrasound, characterized in that the at least one ultrasound source is at least one vibrating plate (31,32,33,34) arranged in the interior of the mixing container (2), or is at least one box profile or square tube (35) including in its interior several ultrasound sources (23); in that the mixing container (2) is capable of rotating by means of a rigid axle (5) which is freely rotatable relative to the mixing container (2) and which runs along the axis of rotation (4), and the mixing container comprising two bearings (81,82) by means of which it is freely rotatable relative to the rigid axle (5), and the axle (5) either runs through the entire mixing container (2) or is in the form of two axle sections (191,192) which run along the axis of rotation (4) of the mixing container (2) but not along its entire length, and the two axle sections (191,192) each protrude into one of the two bearings (81,82) of the mixing container (2), and in that the torque is transmitted directly onto the outer surface of the mixing container (2).

2. The mixer (1) according to claim 1, which has one or more liquid and / or gas-tight sealable openings (61,62) for receiving a mix to be mixed in the mixing container (2) and / or for removing mix from the mixing container (2).

3. The mixer (1) according to claim 1 or 2, characterized in that the axis of rotation (4) deviates from the horizontal by not more than 20°, preferably by not more than 10°, more preferably by not more than 5°, and most preferably is horizontal.

4. The mixer (1) according to any one of the preceding claims, characterized in that the mixing container (2) is rotationally symmetrical about an axis of symmetry (4).

5. The mixer (1) according to claim 4, characterized in that it has a cylindrical lateral surface and two end faces (91,92), and: a) the axis of symmetry (4) coincides with the axis of rotation (4); or b) the axis of symmetry is inclined relative to the axis of rotation (4); or c) the axis of symmetry runs parallel to the axis of rotation (4) but is offset relative to the axis of rotation (4).

6. The mixer (1) according to claim 5, characterized in that at least one of the two end faces (91,92) is removable from the mixing container (2).

7. The mixer (1) according to any one of the preceding claims, characterized in that it comprises an external or internal heater (11) for heating the mixing container (2) or an external or internal cooling.

8. The mixer (1) according to any one of the preceding claims, comprising in the internal volume of the mixing container (2) a grid (12) which separates a part (13) of the internal volume of the mixing container (2) adjacent to the inner surface (21) of the mixing container (2) from the remainder of the internal volume of the mixing container (2), and wherein the mixing container (2) has at least two liquid-tight sealable openings (61,62), of which at least a first opening (61) opens into the remainder of the internal volume and is capable of receiving into the remainder of the interior volume a mix to be mixed and / or is capable of removing mix from the remainder of the interior volume, and at least one second opening (62) opens into the separated part (13) of the interior volume and is capable of removing liquid from this separated part (13) of the interior volume.

9. The mixer according to claim 8, wherein the grid is a perforated grid, the holes of which have a hole diameter in the range of 0.1 to 1.3 mm and preferably have a hole diameter of about 1.25 mm, about 1 mm, about 0.5 mm or about 0.25 mm.

10. The mixer (1) according to any one of the preceding claims, characterized in that: i) the one rigid, internal axis (5) is hollow, has one or more perforations (51) which establish(es) a liquid-conducting connection between the interior volume of the mixing container (2) and the internal cavity of the hollow axle (5), and the hollow axle (5) is connected in a liquid-conducting manner to an upwardly open riser pipe (18); or ii) of the two rigid axle sections (191,192) a first axle section (191) is hollow in the inside and has one or a plurality of perforations (51) which establish(es) a liquid-conducting connection between the interior volume of the mixing container (2) and the internal cavity of the hollow axle section (191), and the internally hollow first axle section (191) is connected in a liquid-conducting manner with a riser pipe (18) which is open at the top; in such a way that, when the mixing container (2) is filled with a mix comprising a liquid, the liquid fills the internal cavity of the internally hollow axle (5) or the internal cavity of the internally hollow first axle section (191), respectively, and the riser pipe (18 ) up to a height that creates a hydrostatic pressure equal to the internal pressure in the mixing container (2); and an increase in the internal pressure in the mixing container (2) is compensable by displacing further liquid from the mixing container (2) via the perforation(s) (51) into the internally hollow axis (5) or into the internally hollow first axis section (191), respectively, and into the riser pipe (18), and a decrease in the internal pressure in the mixing container (2) is compensable by backflow of liquid from the riser pipe (18) via the internally hollow axis (5) or via the internally hollow first axis section (191), respectively, and the perforation(s) (51) into the mixing container (2).

11. The mixer (1) according to any one of the preceding claims, characterized in that the mixing container (2) is filled with a mix comprising barley malt and water, and this mix is preferably suitable for mashing in beer brewing.

12. A use of a mixer (1) according to any of the preceding claims in beer brewing or in the extraction of plants or plant parts.

13. The use according to claim 12, characterized in that the mixer is a mixer according to one of claims 1 to 6 without heating and without a grid inserted into the mixing container, and in that it is used for mashing in the decoction or infusion process.

14. The use according to claim 12, characterized in that the mixer is a mixer according to claim 1 without a grid inserted into the mixing container and in that it is used for mashing in the kettle mashing process.

15. The use according to claim 12, characterized in that the mixer is a mixer according to claim 7 with an additional grid (12) inserted in the mixing container or is a mixer according to claim 8 with additional heating (11), and in that it is used for mashing in the kettle mashing process and for lautering.