METHOD FOR MIXING THE CONTENTS OF A TANK

Description

1. Technical field

[0001] The invention relates to a method for mixing the contents of a tank, particularly in the food, beverage and pharmaceutical industries. 2. State of the art

[0002] In the beverage industry, it is common practice to place nozzle devices inside a tank to mix its contents and to pump quantities of the contents through the nozzle. This creates a flow within the tank, which ensures that the contents are mixed.

[0003] From WO 2011 / 147958 A1, a method for accelerated fermentation and a device for mixing the contents of a tank are known. The device comprises a jet pump, which is arranged at a specific height in the lower part of a fermentation tank for mixing the contents. For mixing, contents of the tank are drawn off at the tank outlet and supplied to the jet pump as a motive medium by means of a pump. In the jet pump, a quantity of the contents of the tank is drawn in by the motive medium, mixed with the motive medium, and injected upwards into the tank, where further mixing of the contents takes place.

[0004] The device described in WO 2011 / 147958 A1 is therefore well-suited to mixing the contents of a tank and, for example, to keeping fermentation yeast suspended in a fermentation tank during beer production. However, this mixing must be stopped when the tank is to be emptied.

[0005] From US 923,571 A, which discloses a method according to the preamble of claim 1, a device for circulating a semi-liquid in a tank is known, in which the liquid is drawn off the wall of the tank and pumped by means of a centrifugal pump through a pipe arranged vertically in the tank onto a conical disk above the liquid level in the tank. Due to gravity, the liquid then flows outwards on the disk and onto an underlying conical plate, on which the liquid flows inwards and back into the tank. To empty the tank contents, the circulation is stopped and the solid fraction of the semi-liquid is allowed to settle. Then the liquid fraction above the solid fraction is drawn off. Finally, the solid fraction is removed.

[0006] From the subsequently published document WO 2017 / 067885 A1, a fermentation tank is known which has a first inlet or outlet, with a first central opening located at the lower end of the fermentation tank for adding or removing product. The fermentation tank further comprises a second and a third inlet or outlet, each with a centrally located opening for adding or removing product, the three openings being arranged at different height levels.

[0007] In dry hopping, hops are added to a tank containing beer or a beer precursor. The goal is to extract specific aroma components from the hops into the beer or precursor. Ideally, the hops should be finely dispersed in the beer to create a large surface area and ensure good flavor transfer. The hop product used for dry hopping is typically in the form of hop pellets, which are ground and pelletized hop cones. These hop pellets break down into a crumbly structure with particle sizes ranging from approximately 100 to 3000 µm upon contact with liquid. The suspension of the hop particles must be maintained for a specific period during dry hopping, as the hops tend to settle. Therefore, it is essential to mix the tank contents as thoroughly as possible during the dry hopping process.Since the hop particles should not settle during the draining of the tank contents, which can take a considerable amount of time with the usual large tanks, mixing should be maintained even during the draining process. This is not possible with prior art mixing devices. The drained "hops in beer" suspension should have only a low solids concentration so that the hop particles can subsequently be filtered out of the suspension using a centrifuge or separator without significant beer loss.

[0008] It is therefore an object of the present invention to provide a method for mixing a tank contents which ensures, in a simple manner, mixing of the tank contents under and after different process conditions. For example, mixing should be ensured during the processing time in the tank, after a preceding sedimentation phase, during a partial sedimentation phase and also when emptying the tank. 3. Summary of the invention

[0009] The above-mentioned tasks are solved by a method for mixing the contents of a tank according to claim 1.

[0010] The above-mentioned tasks are solved by a method for mixing the contents of a tank comprising the following steps: a. Installing a riser pipe extending into the tank through a first pipe connection body at the connection flange; b. Installing a mixing pipe extending into the tank through the first pipe connection body; c. Drawing off tank contents via the riser pipe; d. Pumping the tank contents drawn off via the riser pipe using a pump; e. Connecting the pump outlet so that it is possible to introduce the tank contents drawn off via the riser pipe or the first pipe connection body into the tank via the mixing pipe, as well as to introduce the tank contents drawn off via the riser pipe into the tank via the first pipe connection body; f. Introducing the drawn-off tank contents into the tank and mixing the drawn-off tank contents with the remaining tank contents using the mixing pipe; g.Introducing the tank contents drawn off via the riser pipe into the tank via the first pipe connection body, thereby stirring up sediment from the tank contents; and h. subsequently to step g: Draining tank contents from the tank via the first pipe connection body, whereby draining and mixing via the mixing line take place simultaneously, thereby preventing sedimentation in the tank during the draining process.

[0011] This allows the tank contents below the riser pipe, which is used to draw off tank contents, to settle. Simultaneously, the tank contents in the tank space above the riser pipe can be mixed. This allows for partial sedimentation of the tank contents.

[0012] Furthermore, the process includes the step of draining the tank contents through the first pipe connection, with draining and mixing occurring simultaneously. This simultaneous mixing and draining prevents sedimentation in the tank during the draining process. This ensures a homogeneous suspension of solids in the drained liquid, as is necessary, for example, for removing hop particles by a centrifuge or separator during dry hopping.

[0013] Furthermore, the pump outlet is configured in such a way that the tank contents drawn off via the riser pipe can be fed back into the tank both via the mixing pipe and via the first pipe connection body.

[0014] This method allows the tank contents to be returned to the tank via either the mixing line or the first pipe connection. When returned via the mixing line, the tank contents can be mixed, partially or completely preventing the sedimentation of solids. Partial sedimentation is possible if the tank contents are drawn off via the riser pipe and returned via the mixing line. Complete mixing, however, occurs when the tank contents are drawn off via the first pipe connection and returned via the mixing line. Furthermore, sediment accumulated in the lower part of the tank can be diluted or resuspended and mixed when tank contents are drawn off via the riser pipe or the mixing line and returned via the first pipe connection.The method according to the invention therefore allows the mixing device to be used flexibly for different mixing tasks. In particular, the method can also be used to carry out new processing, mixing or sedimentation processes, such as those that are advantageous, for example, in dry hopping during beer production, although the method is not limited to this.

[0015] Furthermore, the process includes the step of stirring up sediment from the tank contents when the tank contents are drawn off via the riser pipe and the pump outlet is connected to the first pipe connection. This allows sediment accumulated in the lower part of the tank to be selectively stirred up or diluted, either to facilitate drainage or to mix it back into the tank contents.

[0016] The process is preferably used for dry hopping, where the tank is a fermentation tank and the tank contents contain hop particles. This process can be particularly advantageous in dry hopping during beer production, especially for homogenizing the hop particles in the liquid, even during the time-consuming draining process.

[0017] Preferably, a device for mixing the contents of a tank comprises a first pipe connection body arranged on a connection flange of the tank, a riser pipe extending through the first pipe connection body into the tank, a mixing line extending through the first pipe connection body into the tank, and a pump whose outlet can be connected at least to the mixing line and whose inlet can be connected to both the first pipe connection body and the riser pipe. A pipe connection body is understood to mean any type of connecting element for a pipe to a tank. These can be, for example, so-called Varivent connection elements, but also pipe bends, tees, or similar components.

[0018] This makes the device versatile and allows it to draw the tank contents for mixing from either the first pipe connection or the riser pipe, and then pump them to a mixing nozzle located inside the tank. Because the pump inlet can also be connected to the riser pipe, it's possible to mix the tank contents simultaneously while the tank is being emptied via the pipe connection. Alternatively, connecting the pump inlet to the pipe connection ensures complete mixing of the tank contents, as in this case, the contents are drawn from the lowest point of the tank for mixing.Additionally, connecting the riser pipe to the pump inlet allows for mixing of the tank contents if, simultaneously or beforehand, a portion of the tank contents is intended to settle and should not be stirred up or mixed again. The present device therefore enables a wide variety of operating modes, such as mixing during discharge or mixing after or during the sedimentation of a portion of the tank contents. The device thus facilitates new processing and mixing techniques, such as those used in dry hopping during beer production.

[0019] The pump outlet can also be connected to the first pipe connection body if the pump inlet is connected to the riser pipe. This connection allows sediment that has accumulated at the lowest point of the tank after a sedimentation step, particularly in the area of ​​the pipe connection body, to be loosened or diluted, making it easier to remove. It also allows the sediment to be diluted sufficiently to enable complete or partial mixing of the tank contents via the mixing line or a mixing nozzle, without the risk of clogging the mixing line or nozzle. Therefore, already settled solids can be completely or partially mixed with the remaining tank contents.

[0020] The pump outlet can also be connected to the riser pipe if the pump inlet is connected to the first pipe connection. This connection option allows, for example, a gentle partial mixing of the lower tank contents without using the mixing line, which has a strong mixing effect on the tank contents. This solution can also be used when large volume flows need to be circulated within the tank. This is necessary, for example, if a heat exchanger is installed in the pipe between the first pipe connection and the riser. Since tank cooling usually needs to occur quickly, high mass flow rates must be cooled. These cannot usually be routed through the mixing line, as its dimensions may be insufficient. The same applies, of course, to heating processes.

[0021] Preferably, the mixing line runs inside the riser pipe, and more preferably concentrically within the riser pipe. This makes it possible to connect the mixing device to a standard connection flange of a tank, in particular a cylindroconical tank (CCT), without structurally modifying the tank itself. Thus, any CCT can be easily and reversibly equipped or retrofitted with a mixing device according to the invention. The description explains the invention using a CCT as an example. However, it is equally applicable to tanks with any other type of end, e.g., dished ends or flat ends. When a connection flange is mentioned herein, this also includes welded connections.

[0022] Preferably, the riser pipe extends essentially vertically upwards into the tank and / or has an open end. This allows the riser pipe to be used effectively for drawing in tank contents at an elevated liquid level. Conversely, it can also be used as an outlet at an elevated liquid level for mixing the tank contents.

[0023] Preferably, the device further includes a deflector plate attached to the riser pipe above the first pipe connection body. This improves the agitation and dilution of sediment when tank contents, which were drawn off via the riser pipe, are returned to the tank via the pipe connection body.

[0024] Preferably, a mixing nozzle is connected to the upper end of the mixing line. The mixing nozzle allows the jet of the contents being introduced into the tank to be shaped, thus achieving better mixing of the contents.

[0025] Preferably, the mixing nozzle is a jet pump configured to draw contents from the tank and mix them with contents pumped to the mixing nozzle via the mixing line. This allows the mixing nozzle not only to inject the pumped contents into the tank but also to mix them with additional contents drawn in by the nozzle itself. This enables a very thorough mixing of the tank contents.

[0026] Preferably, the mixing line can still be used to draw off tank contents. If the mixing nozzle or jet pump is omitted and the end of the mixing line extends into the tank without any attachments, this can also be advantageous. In this case, the mixing line can also be used to draw off the tank contents. These contents can then be returned to the tank via the riser pipe and / or the first pipe connection, or the tank contents can be emptied from the tank in this way. This allows for the introduction and / or withdrawal of tank contents at another level within the tank. This enables, for the first time, even greater flexibility in the use of a tank in the brewing process.

[0027] Preferably, the lower end of the riser is connected to a second pipe connection body. This allows the riser to be integrated into the fluid circuit using standardized means.

[0028] Preferably, the riser pipe is shorter than the mixing pipe. This means that the upper end of the mixing pipe or the mixing nozzle is positioned at a higher level in the tank compared to the end of the riser pipe. This results in different mixing methods depending on whether the riser pipe or the mixing nozzle is used as the outlet.

[0029] Preferably, the riser pipe extends at least a length of 0.5 m, or preferably at least a length of 1 m, or preferably at least a length of 1.5 m measured from the connection flange into the tank.

[0030] The mixing line, preferably including the mixing nozzle, extends at least 0.7 m, or preferably at least 1.2 m, or preferably at least 1.7 m, from the connection flange into the tank. These lengths of the riser and mixing line, optionally including the mixing nozzle, are particularly advantageous when mixing hop particles or yeast cells in a fermentation tank during beer production. The lengths may depend on the tank size and geometry.

[0031] Preferably, the first pipe connection body is also connected to an inlet and outlet line for filling and emptying the tank. This allows the tank to be filled and emptied via the first pipe connection body, especially when the tank contents are being mixed simultaneously. However, this inlet and outlet line does not necessarily have to be directly connected to the pipe connection body. An indirect connection is also possible. Furthermore, the inlet and outlet lines can be combined or separate. 4. Brief description of the drawings

[0032] Preferred embodiments of the invention are described below with reference to the drawings, which show: Fig. 1: a sectional side view of a lower region of a cylindroconical tank with an embodiment of a device for mixing the tank contents and a schematic representation of further components of the device in an operating mode for mixing the tank contents; Fig. 2: the device according to Fig. 1 in a different operating mode when mixing the tank contents; Fig. 3: the device according to Fig. 1 in another operating mode when diluting or stirring up sediment; Fig. 4: a three-dimensional partial view of a lower region of a cylindroconical tank with an embodiment of a device for mixing the tank contents; and Fig. 5: a sectional side view of the lower region of the tank made of Fig. 4 with parts of the device for mixing the tank contents in detail. 5. Description of preferred embodiments

[0033] Preferred embodiments of the invention are described in detail below with reference to the drawings.

[0034] Fig. 1 Figure 1 shows the lower section of a cylindroconical tank (CCT) 10, such as those used as fermentation and / or storage tanks in breweries, with a device 1 for mixing the tank contents. A connection flange 14 is located at the lower conical outlet of the tank 10, to which a first pipe connection body 20 is connected. The tank 10 can be filled and emptied via a main line 90, which is connected to this first pipe connection body 20. The connection flange 14 preferably has a nominal diameter (DN) of 100 mm.

[0035] As a further component of the device 1, a riser pipe 40 extends through the connection flange 14 into the tank 10. The riser pipe 40 is essentially vertically oriented and preferably penetrates the opening of the connection flange 14 coaxially. The nominal diameter DN of the riser pipe is preferably 65 mm. The contents of the tank 10 can be drawn off or fed into the tank 10 via the riser pipe 40 at a certain height. At its lower end, the riser pipe 40 is connected to a second pipe connection body 30, which hydraulically connects the riser pipe 40 to the other components of the device 1.

[0036] Additionally, a mixing line 50 extends through the connection flange 14 into the tank. The mixing line 50 runs essentially coaxially within the riser pipe 40 and is also vertically oriented. The upper end of the mixing line 50 can be open or a mixing nozzle 52 can be connected to it. Preferably, the mixing nozzle 52 is a jet pump 52 that can itself draw tank contents from the tank 10 and mix them with the motive medium supplied to it through the mixing line 50. If no mixing nozzle 52 is installed on the mixing line 50, the mixing line 50 can also be used to draw in tank contents.

[0037] Furthermore, the device 1 includes a pump 60 which can be connected in various ways to the first pipe connection body 20, the riser 40, and the mixing line 50 by means of piping 92 and valves 71-80. The different connection options allow for different operating states of the device for mixing, sedimentation, and cleaning in place (CIP).

[0038] To fill or empty the tank without simultaneous mixing, valve 71 is open and all other valves are closed.

[0039] For mixing the tank contents in a first operating mode, as described in Fig. 1As shown, valves 73, 76, and 77 are open, and the other valves are closed. The inlet 62 of pump 60 is thus connected to the riser pipe 40 via the second pipe connection body 30. The outlet 64 of pump 60 is connected to the lower end of the mixing line 50. The tank contents are thus drawn off via the riser pipe 40 and fed to pump 60. The pump 60 is in operation and pumps the drawn-off tank contents to the mixing line 50, which introduces the contents into the tank 10 at an elevated position, thereby ensuring thorough mixing. Depending on the pump 60's output, partial sedimentation can also be achieved in the area below the upper end 42 of the riser pipe 40. The output of pump 60 can be regulated via a speed controller 83 of pump 60.

[0040] Mixing in the first operating mode can also be carried out while the contents of tank 10 are being drained. In this case, pump 60 is running, valves 71, 73, 76, and 77 are open, and the other valves are closed. This ensures a homogeneous distribution of suspended particles in the liquid, even during draining. This operating mode can also be used when filling the tank to mix the contents during the filling process.

[0041] In another in Fig. 2In the operating mode shown, valves 72 and 77 are open, the other valves are closed, and the pump is running. This connects the inlet 62 of the pump 60 to the first pipe connection body 20 and the outlet 64 of the pump 60 to the mixing tube 50. In this operating mode, the contents of the tank 10 are drawn off at its lowest point and returned to the tank via the mixing tube 50 and a mixing nozzle 52 connected to it. This results in optimal mixing of the entire contents of the tank 10.

[0042] In another in Fig. 3In the operating mode shown, valves 73, 75, and 76 are open, the other valves are closed, and pump 60 is running. This connects pump 60's inlet 62 to the riser pipe 40 and pump 60's outlet 64 to the first pipe connection body 20. In this operating mode, sediment that has settled in the lower part of tank 10 can be stirred up or diluted, making it easier to subsequently remove it from tank 10 or mix it back into the tank contents. To improve the turbulence of the sediment, a deflector plate 70 is attached to the riser pipe 40 just above the first pipe connection body 20. This plate turbulences the flow of tank contents coming from the pipe connection body 20, thus improving the sediment capture.

[0043] In another operating mode (not shown), valves 72, 76, and 79 are open, the other valves are closed, and pump 60 is running. In this mode, the inlet 62 of pump 60 is connected to the first pipe connection body 20, and the outlet 64 of pump 60 is connected to the riser pipe 40. In this mode, the withdrawn tank contents are introduced via the riser pipe 40, and thus at a lower level than via the mixing line 50 or the mixing nozzle 52. This allows for gentler mixing than via the mixing nozzle 52. This operating mode can also be used, for example, for a cooling process, as large mass flow rates are required. These mass flow rates may no longer be able to be conveyed through the mixing line 50 and must be introduced into the tank via the riser pipe 40. A necessary heat exchanger (not shown) is then variably integrated into any pipe outside the tank.One possible location would be, for example, between pump 60 and valve 79.

[0044] Overall, the device 1 according to the invention allows for the combination of various operating modes, making it suitable for a wide range of mixing and sedimentation applications, particularly in the beverage and food industries. Preferably, the device 1, or the method carried out with it, can be used in its various operating modes for dry hopping in a beer brewing process.

[0045] Furthermore, the device is suitable for Cleaning in Place (CIP). For CIP of the mixing line 50 and the mixing nozzle 52, valves 72, 73, 74 and 77 are open and the other valves are closed. Pump 60 is running during CIP.

[0046] For the CIP of the riser pipe 40, valves 72, 76 and 79 are open, the other valves are closed and pump 60 is in operation.

[0047] For the CIP of valve 75, valves 72, 73, 74 and 75 are open, the other valves are closed and pump 60 is in operation.

[0048] To drain the CIP fluid from the device 1 and the tank 10, all valves 71 - 80 are open and the pump 60 is out of service.

[0049] Device 1 further includes measuring instruments 81, 82 and 84, for example flow meters for volume and / or mass, temperature measuring instruments, pH meters, pressure gauges, turbidity and / or color meters, or other measuring instruments for the beverage industry. The exact number and arrangement of measuring instruments is arbitrary.

Claims

1. Method for mixing the contents of a tank (10), comprising the following steps: a. arranging a riser pipe (40) extending through a first pipe connection body (20) at the connection flange (14) into the tank (10); b. arranging a mixing pipe (50) extending through the first pipe connection body (20) into the tank (10); c. detracting tank contents via the riser pipe (40); d. pumping the tank contents detracted via the riser pipe (40) by means of a pump (60); e. interconnecting the outlet (64) of the pump (60) so that it is possible both to introduce the tank contents detracted via the riser pipe (40) or the first pipe connection body (20) into the tank (10) via the mixing pipe (50) and to introduce the tank contents detracted via the riser pipe (40) into the tank (10) via the first pipe connection body (20); f. introducing the detracted tank contents into the tank (10) and mixing the detracted tank contents with the remaining tank contents by means of the mixing pipe (50); characterized by g. a step of introducing the via the riser pipe (40) detracted tank contents into the tank (10) via the first pipe connection body (20), wherein sediment of the tank contents is whirled up; and h. subsequent to step g: discharging tank contents from the tank (10) via the first pipe connection body (20), wherein discharging and mixing via the mixing pipe (50) take place simultaneously and sedimentation in the tank (10) during the discharging process is thereby prevented.

2. Method according to claim 1, wherein the riser pipe (40) is shorter than the mixing pipe (50).

3. Method according to one of claims 1 or 2, wherein the mixing pipe (50) runs inside the riser pipe (40), preferably runs concentrically inside the riser pipe (40).

4. Method according to one of claims 1 to 3, wherein the riser pipe (40) extends substantially vertically upwards into the tank (1) and / or has an open end (42).

5. Method according to one of claims 1 to 4, wherein a mixing nozzle (52) is connected to the upper end of the mixing pipe (50).

6. Method according to claim 5, wherein the mixing nozzle (52) is a jet pump which is configured to detract tank contents from the tank (10) and mix them with tank contents which are pumped via the mixing pipe (50) to the mixing nozzle (52).

7. Method according to one of claims 1 to 6, wherein the lower end of the riser pipe (40) is connected to a second pipe connection body (30).

8. Method according to one of claims 1 to 7, further comprising the step of detracting tank contents via the mixing pipe (50).

9. Method according to one of claims 1 to 8, wherein it is used for dry hopping, and wherein the tank (10) is a fermentation tank and the tank contents comprise hop particles.