Foam pump for foaming liquid media

Abstract

The present invention relates to a foam pump and to a method for foaming liquid media. The liquid medium can be drawn in by means of the foam pump, the drawn-in medium can be mixed with gas within the foam pump to form a mixture, and the mixture can be frothed up to form a foam. The invention is characterised in that the foam pump comprises a homogenising section (22) for homogenising the foam, which homogenising section comprises a preferably rod-like homogenising shaft (23) that rotates during operation of the foam pump and is arranged within an elongated cavity (25) which is delimited by a circumferential, in particular cylindrical, inner surface (27), and through which the foam can be conveyed, and the homogenising shaft has a plurality of homogenising elements (24) for homogenising the foam, in particular by breaking up and / or reducing the size of gas bubbles within the foam.

Description

[0001] Foam pump for foaming liquid media

[0002] Description

[0003] The present invention relates to a foam pump for foaming liquid media, in which the liquid medium can be drawn in, in which the drawn-in medium can be mixed with gas, in particular air, to form a mixture, and in which the mixture can be foamed. The invention further relates to a corresponding method for foaming liquid media.

[0004] Such foam pumps are known in the prior art and can be used, for example, to generate adhesive foam from liquid adhesive as the medium and air as a gas or gas mixture (in this application, the term "gas" also includes gas mixtures of several different gases). A disadvantage is that the foams produced by such pumps are often not sufficiently homogenized. Even if special measures for foam homogenization are taken in such pumps, such as the use of static mixers or sieves, these are often not efficient enough, too complex, and / or too prone to failure, or have other disadvantages.

[0005] Based on this, the object of the present invention is to further develop foam pumps of the type mentioned above and the method mentioned above for foaming liquid media.

[0006] This problem is solved by a foam pump having the features of claim 1 and a method having the features of claim 18.

[0007] Accordingly, a foam pump according to the invention is characterized in that the foam pump has a homogenization section for homogenizing the foam, which comprises a preferably rod-shaped homogenization shaft rotating during operation of the foam pump, which is arranged in an elongated cavity bounded by a circumferential, in particular cylindrical, inner surface, through which the foam can be conveyed, and which has several homogenizing agents for homogenizing the foam.

[0008] The use of such a homogenization section within the foam pump, comprising a homogenization shaft, according to the invention, enables a structurally relatively simple yet efficient homogenization of the generated foam. After generation, the foam can be directly transferred within the foam pump to the homogenization section and homogenized there. During this homogenization process, gas bubbles in the liquid medium contained within the foam are reduced and / or diminished in size by the homogenization shaft or its homogenizing agent during rotation.

[0009] Preferably, the homogenizing means of the shaft can each be formed by a depression in the outer surface of the homogenizing shaft, in particular a depression with a regular or irregular shape.

[0010] The respective depression can be designed as a preferably elongated depression, in particular extending in the circumferential and / or axial direction of the homogenizing shaft, with a triangular, trapezoidal, rectangular, semi-circular, semi-elliptical, trough-shaped or (regularly or irregularly) polygonal contour in cross-section.

[0011] The homogenizing wave can, furthermore, have a number of preferably elongated, in particular wider and / or longer, main recesses, as well as a number of elongated, in particular narrower and / or shorter, auxiliary recesses, of which two main recesses spaced axially and / or circumferentially apart are connected by an auxiliary recess arranged between them, so that foam can flow from one of the two main recesses via the auxiliary recess to the other of the two main recesses. In the axial direction of the homogenizing wave, several groups of each pair of main recesses connected by an auxiliary recess can be arranged at an axial distance from one another, in particular axially one above the other. The auxiliary recesses of different groups can, in turn, be arranged circumferentially offset from one another.

[0012] The cavity in which the homogenizing shaft sits can be formed by a through-opening bounded by the inner surface in a solid, in particular disc-shaped, plate of the foam pump, or by several aligned through-openings, each bounded by a section of the inner surface, in a series of stacked solid plates. The plates can have any shape. In particular, they can be disc-shaped, but also cube-shaped, cuboid-shaped, etc.

[0013] The inner surface bordering the cavity may also contain several homogenizing agents, in particular those that interact with the homogenizing agents of the homogenizing wave for the purpose of homogenizing the foam.

[0014] The homogenizing agents of the inner surface can also be formed by a depression in the outer surface, in particular a depression with a regular or irregular shape.

[0015] The depressions of the inner surface can also be designed as preferably elongated depressions, in particular extending in the axial direction and / or circumferential direction of the homogenizing shaft, with a triangular, trapezoidal, rectangular, semi-circular, semi-elliptical, trough-shaped or regularly or irregularly polygonal contour in cross-section.

[0016] Regarding the pump stages of the foam pump, it can have a first pump stage for drawing in the liquid medium, in particular from a medium source or reservoir, and a second pump stage for mixing the drawn-in medium with gas, in particular from a gas source or reservoir, and / or for foaming the mixture of the liquid medium and the gas. The homogenization section can preferably be arranged downstream of the second pump stage.

[0017] The gas can be supplied to the foam pump from the gas source via a gas inlet. The foam pump, or its gas inlet, may have a check valve that prevents the liquid medium or adhesive from entering the gas inlet.

[0018] The first and second pump stages then enable the liquid medium or the mixture of liquid medium and gas to be pumped within the foam pump, particularly within a delivery channel in the foam pump. The first and second pump stages can each be formed by or comprise a gear pump, with both gear pumps being driven by a common drive shaft of the foam pump.

[0019] It can be specifically provided that the liquid medium is conveyed within the conveying channel from the second pumping stage into a mixing section of the conveying channel, where the mixing of the liquid medium with the gas and the foaming process then take place. The foamed liquid medium can then be conveyed along the conveying channel to the cavity of the homogenization section of the foam pump, which in this case forms a section of the conveying channel and in which the homogenization shaft rotates or is arranged to rotate.

[0020] Particularly advantageous is the ability to drive the homogenization shaft via the common drive shaft of both gear pumps in the foam pump. This allows for the production of a particularly compact foam pump.

[0021] Furthermore, a gear can be arranged on the homogenization shaft, which meshes with and rotates together with a gear of the gear pump of the first or second pump stage. This gear is mounted on a shaft of the gear pump of the first or second pump stage, in particular a shaft common to both gear pumps of the first or second pump stage. The gear of the homogenization shaft can preferably rotate with the meshing gear of the first or second pump stage at a gear ratio within a range of 1:1 to 10:1, preferably 1.5:1.

[0022] Furthermore, the homogenization shaft is preferably designed in such a way that, unlike the first and second pump stages, it does not convey the foam or the foamed mixture of liquid medium and gas, but exclusively homogenizes the foam.

[0023] Furthermore, the homogenizing shaft in the pump can be guided parallel to the shaft of the gear pump of the first or second pump stage, with whose gear the gear of the homogenizing shaft meshes.

[0024] The outer surface of the homogenizing shaft and / or the shaft of one or more gear pumps and / or one, several, or each gear of the foam pump and / or the plates of the foam pump may furthermore be surface-hardened, in particular by nitriding, carbonitriding, case hardening, or titanium nitriding. Alternatively or additionally, it may be provided that the gears of one or more gear pumps and / or the gear of the homogenizing shaft are made of thermoplastic polymer.

[0025] Further features of the present invention will become apparent from the attached claims, the following description of preferred embodiments, and the attached drawings. These show:

[0026] Fig. 1 shows a schematic cross-section through a first embodiment of a foam pump, in which the homogenizing shaft is driven by a drive shaft that simultaneously forms the main shaft of the gear pumps of the first and second pumping stages of the foam pump and is connected to the homogenizing shaft via two meshing gears. Fig. 2 shows a cross-section through a second embodiment of a foam pump, in which the homogenizing shaft forms the drive shaft for the gear pumps of the first and second pumping stages.

[0027] Fig. 3 shows a cross-section through a third embodiment of a foam pump, which is constructed similarly to the foam pump according to Fig. 1, but in which the meshing gears are wet gears, namely they are surrounded by the liquid medium or foam.

[0028] Fig. 4 shows an oblique view of the interconnected shafts of the first embodiment of the foam pump,

[0029] Fig. 5 shows a cross-section through the homogenizing shaft and part of the surrounding wall of one of several solid pump plates or pump discs of the foam pumps of Figs. 1-3, which includes this,

[0030] Fig. 6 shows a longitudinal section through the homogenization shaft of the foam pumps of Figs. 1-3.

[0031] Fig. 7 shows one of the pump plates of the foam pump shown in Figs. 1-3.

[0032] Fig. 8 shows an alternative embodiment of such a pump plate.

[0033] A first embodiment of a foam pump 10 according to the invention, with which, for example, adhesive foam can be produced from liquid adhesive, is shown in section in Figure 1. From top to bottom, it comprises five (there can, of course, be more or fewer) in particular disc-shaped, solid (pump plates 11 with various recesses or bores 12, each aligned with one another. One of the plates 11, namely a middle plate 11A, is shown in top view in Figure 7.

[0034] A first pumping stage 13 of the foam pump 10 ensures that the liquid medium, in particular liquid adhesive, is pumped from a medium source, such as a reservoir for liquid adhesive, via a supply line or feeder 14 into a delivery channel 21 of the foam pump 10. For this purpose, the first pumping stage 13 is designed as a gear pump with two meshing gears 15A and 15B. Gear 15A is mounted on a main shaft 16 of the foam pump 10, which is driven by a motor (not shown), such as a servo motor. Gear 15B is mounted on a secondary shaft 20, which, in the embodiment shown in Figure 1, is driven by the main shaft 16, as will be explained in more detail below.

[0035] Downstream of the first pumping stage in the direction of flow, there is a second pumping stage 17 in which the supplied liquid medium is mixed with a gas, such as air, and foamed. For this purpose, a gas supply 18 terminates in the area of ​​the second pumping stage, through which the gas from a gas source (not shown) is conveyed into the foam pump 10 or into the corresponding mixing area of ​​the second pumping stage 17. The second pumping stage 17 is also designed as a gear pump. A gear 19 A of the second pumping stage is also mounted on the main shaft 16, and a second gear 19 B, meshing with gear 19 A, is mounted on the auxiliary shaft 20, which is driven by the main shaft.

[0036] Downstream of the second pump stage 17, the conveying channel 21 leads to a homogenization section 22 of the foam pump 10, in which the foam produced by the second pump stage 17 is homogenized. In particular, air bubbles in the foam are reduced and / or made smaller.

[0037] For this purpose, the homogenization section 22 has a rod-shaped homogenization shaft 23 with homogenizing agents 24, which rotates within a cylindrical, elongated cavity 25 adapted to the homogenization shaft 23. This cavity is formed by a group of aligned bores or through-openings 12 of the plates 11 and is laterally bounded by a cylindrical inner surface 27 formed by the plates 11. The cavity 25 is part of the delivery channel 21 of the foam pump 10, so that the foam produced is conveyed through this cavity 25 during pump operation.

[0038] The homogenizing agents 24 of the homogenization wave 23 act in the present case

[0039] Case for the purpose of homogenizing the foam produced by the foam pump 10 with homogenizing agents 26 of the homogenization section 22.

[0040] Specifically, the homogenizing means 24 of the homogenizing wave 23 comprise elongated depressions 28 arranged on the outer surface 29 of the homogenizing wave 23. The homogenizing means 26 of the inner surface 27 bounding the cavity 25 are also depressions, namely elongated depressions 30 of this inner surface 27. Neither the depressions 28 nor the depressions 30 necessarily have to be elongated.

[0041] The recesses 28 of the homogenizing shaft 23 comprise a first type of recess, namely main recesses 28 A, which are designed here as elongated recesses extending in the axial direction with a semicircular cross-section, cf. Fig. 5. As can be seen, for example, in Figure 4, several groups of such main recesses 28 A can be arranged distributed over the outer surface 29 of the homogenizing shaft 23. For example, three groups of main recesses 28 A arranged one below the other at an axial distance from each other, wherein in each group several main recesses 28 A are arranged side by side in the circumferential direction of the homogenizing shaft 23.

[0042] Individual main depressions 28 A of groups of main depressions 28 A arranged directly above one another are in turn connected in pairs by auxiliary depressions 28 B which, however, are designed as narrower depressions compared to the main depressions 28 A and also have a partially circular contour, so that foam can be transported via the auxiliary depressions 28 B from the upper main depression 28 A of each pair of main depressions 28 A to the lower main depression 28 A.

[0043] The recesses 30 of the inner surface 27 are also axially extending recesses, including those with a semicircular contour. Each inner surface 27 of each of the plates 11 that together form the cavity 25 can have such a recess 30. As shown in Figures 5 and 7, such a plate 11 can, for example, have three such recesses 30 distributed symmetrically in the circumferential direction, i.e., with equal angular spacing between them. In contrast, an alternative plate 1T shown in Figure 8 has, for example, only two recesses 30.

[0044] Overall, the recesses 28 and the recesses 30 are designed and interact in such a way that, when the homogenization wave 23 is rotated, the aforementioned effects of homogenizing the foam are achieved.

[0045] As already described at the beginning, the recesses 28 and 30 can also have completely different shapes than the semicircular contour described in the present embodiment, such as a triangular, trapezoidal, rectangular, semi-elliptical or regularly or irregularly polygonal contour in cross-section.

[0046] Furthermore, they do not have to be directed in the axial direction, but can also, for example, run completely or partially in the circumferential direction or completely or partially obliquely to the axial direction, etc.

[0047] To enable the rotation of the homogenization shaft 23, various configurations exist. In the embodiment shown in Figure 1, the homogenization shaft 23 is driven by the main shaft 16. For this purpose, a further gear 31 A is mounted on the main shaft 16, which meshes with a gear 31 B located on the homogenization shaft 23. In this embodiment, both gears 31 A and 31 B are dry-running gears, meaning they are not exposed to the liquid medium or foam. Shaft seals 32, which seal these gears 31 A and 31 B in the area of ​​the shafts 16 and 23 respectively, can be seen in Figure 1.

[0048] This is different in the embodiment of Figure 3, in which the gears 31 A and 31 B are wet rotor gears, i.e. they are arranged accordingly in the area of ​​the conveying channel 21 or are connected to it in a fluid-conducting manner and are surrounded by the medium.

[0049] The embodiment of Figure 2 differs from the embodiment of Figure 1 primarily in that in this case the homogenizing shaft 23 forms the drive shaft or is driven by the motor not shown and its movements are transmitted to the main shaft 16.

[0050] It is understood that the respective shaft 16 or 23, which each forms the drive shaft and is driven by the motor, may also be divided or connected to the motor via a connecting shaft or other connecting gear.

[0051] The liquid medium or liquid adhesive supplied to the foam pump 10 via the feeder 14 can advantageously be supplied hydraulically under hydraulic pressure to facilitate the mixing of liquid and gas in the second pumping stage 17. This pressure can be controlled, for example, by a closed pressure control system at the pump inlet, which reads the adhesive pressure and acts upon it, thereby limiting the pressure to a specific maximum value. Furthermore, it is advantageous to control the percentage mass flow rate of the medium and gas.

[0052] The gas supplied via the gas inlet 18 is preferably introduced under pneumatic pressure through a manually or automatically activatable valve (not shown), which facilitates mixing with the liquid and improves the homogeneity of the generated foam. The valve can be a check valve that prevents the liquid medium or adhesive from entering the gas inlet 18 and allows gas flow only towards the foam pump 10.

[0053] Regarding the aforementioned gears 15 A, 15 B, 19 A, 19 B, 31 A, 31 B, these may be made of polymeric and / or metallic material and therefore require adequate lubrication to prevent wear and stiffening and to ensure smooth and efficient operation of the system.

[0054] If the gears 15A, 15B, 19A, 19B, 31A, and 31B are wet-running gears through which the liquid medium and / or foam circulates (compare gears 31A and 31B in Figure 3), they do not require additional lubrication to ensure their operation and extend their service life. However, if they are dry gears, as in Figures 1 and 3, lubrication is advisable to extend their service life. Therefore, an externally accessible feed channel 19 can be incorporated into one of the plates 11 to facilitate lubrication of the dry gears and thus ensure optimal operation and a longer service life.

[0055] As regards the rotational speed of the homogenizing shaft 23, it can rotate at the same, higher, or lower speeds compared to the main shaft 16. Preferably, however, at higher speeds, such as in a ratio range of 1:1 to 10:1, preferably in a ratio of 1.5:1, thereby ensuring the most synchronous and precise movement possible.

[0056] As explained, the harmonization shaft 23 can preferably be driven together with the main shaft 16 by a common drive shaft, which can simultaneously be the harmonization shaft 23 or the main shaft 16 itself. Theoretically, however, it is also conceivable that the harmonization shaft 23 is driven by a different drive shaft than the main shaft 16. As those skilled in the art will recognize, various configurations are possible here, in which one or both pump stages 13, 17 and / or the harmonization shaft 23 are driven separately.

[0057] The harmonization shaft 23 is guided in an upper and a lower section by guides 33, which ensures smooth and controlled operation. The guides 33 used can be fixed or rotatable, such as ball bearings. The guides 33 can be made, for example, of thermoplastic polymer or metal, preferably bronze or brass.

[0058] As mentioned at the outset, the harmonization shaft 23 and / or the shaft 16, 20 of one or both gear pumps 13, 17 and / or one, several, or each gear 15A, 15B, 19A, 19B, 31A, 31B of the foam pump 10 and / or the plates 11, 1T of the foam pump 10 may also be specially hardened or subjected to a hardening treatment to ensure their durability and strength under demanding operating conditions. The treatment may be any type of surface hardening, such as nitriding, carbonitriding, case hardening, or cyanidating. Preferably, a titanium nitriding treatment is carried out, which ensures durability, hardness, and wear resistance.

[0059] *****

[0060] Reference symbol list

[0061] 10 Foam pump 31 B Gear

[0062] 11 plates homogenization wave

[0063] 11 A Plate 32 Shaft seals

[0064] 11 ' plates 33 guides

[0065] 12 holes

[0066] 13 first pump stage

[0067] 14. Supply of liquid medium

[0068] 15 A Gear first pump stage

[0069] 15 B Gear first pump stage

[0070] 16 Main wave

[0071] 17 second pump stage

[0072] 18 Gas supply

[0073] 19 Feed

[0074] 19 A Gear second pump stage

[0075] 19 B Gear second pump stage

[0076] 20 secondary shaft

[0077] 21 Conveyor channel

[0078] 22 Homogenization section

[0079] 23 homogenization wave

[0080] 24 Homogenizing agent wave

[0081] 25 cavity

[0082] 26 Homogenizing agent inner surface

[0083] 27 Inner surface of cavity

[0084] 28 depressions

[0085] homogenization wave

[0086] 28 A Main depressions

[0087] 28 B Auxiliary depressions

[0088] 29 outdoor area

[0089] homogenization wave

[0090] 30 recesses on the inner surface

[0091] 31 A Gear Main Shaft

Claims

Patent claims 1. Foam pump for foaming liquid media, with which the liquid medium can be drawn in, in which the drawn-in medium can be mixed with gas to form a mixture and in which the mixture can be foamed into a foam, characterized in that the foam pump has a homogenization section (22) for homogenizing the foam, which comprises a preferably rod-shaped homogenization shaft (23) rotating during operation of the foam pump, which is arranged in an elongated cavity (25) bounded by a circumferential, in particular cylindrical, inner surface (27), through which the foam can be conveyed, and which has several homogenizing means (24) for homogenizing the foam, in particular by reducing and / or decreasing the size of gas bubbles in the foam.

2. Foam pump according to claim 1, characterized in that the homogenizing means (24) of the homogenizing shaft (23) are each formed by a recess (28) in the outer surface of the homogenizing shaft (23), in particular a recess (28) with a regular or irregular shape.

3. Foam pump according to claim 2, characterized in that the recesses (28), which preferably extend in the circumferential and / or axial direction of the homogenizing shaft (23) and are in particular elongated, have a triangular, trapezoidal, rectangular, semicircular, semi-elliptical, trough-shaped or (regularly or irregularly) polygonal contour in cross-section.

4. Foam pump according to one or more of the preceding claims, characterized in that the homogenization shaft (23) has a number of preferably elongated, in particular wider and / or longer main recesses (28 A) and a number of preferably elongated, in particular narrower and / or shorter auxiliary recesses (28 B), of which two axially and / or circumferentially spaced main recesses (28 A) are connected by an auxiliary recess (28 B) arranged between them, such that Foam can flow from one of the two main depressions (28 A) via the auxiliary depression (28 B) to the other of the two main depressions (28 A).

5. Foam pump according to claim 4, characterized in that several groups of each of two main recesses (28 A) connected to each other by an auxiliary recess (28 B) are arranged at a distance from each other, in particular from each other, in the axial direction, and that the auxiliary recesses (28 B) of different groups are arranged offset from each other in the circumferential direction.

6. Foam pump according to one or more of the preceding claims, characterized in that the cavity (25) in which the homogenizing shaft (23) is seated is formed by a through-opening (12) bounded by the inner surface (27) in a solid, in particular disc-shaped plate (11 , 11') of the pump or by several through-openings (12) of a series of solid, in particular disc-shaped plates (11 , 11') arranged one on top of the other, aligned with each other and bounded by a section of the inner surface (27).

7. Foam pump according to one or more of the preceding claims, characterized in that the inner surface (27) defining the cavity (25) also has several homogenizing means (26), in particular homogenizing means (26) cooperating with the homogenizing means (24) of the homogenizing shaft (23) for the purpose of homogenizing the foam.

8. Foam pump according to one or more of the preceding claims, characterized in that the homogenizing means (26) of the inner surface (27) are each formed by a depression (30) in the inner surface, in particular a depression (30) with a regular or irregular shape.

9. Foam pump according to claim 8, characterized in that the recesses (30) of the inner surface (27) are each elongated, in particular extending in the axial direction and / or circumferential direction, recesses (30) with a triangular, trapezoidal, rectangular, semicircular, semi-elliptical, trough-shaped or regularly or irregularly polygonal contour in a cross-section.

10. Foam pump according to one or more of the preceding claims, characterized in that the foam pump has a first pumping stage (13) for drawing in the liquid medium and a second pumping stage (17) for mixing the drawn-in liquid medium with gas and / or for foaming the mixture into foam, and that the homogenization section (22) is arranged downstream of the second pumping stage (17).

11. Foam pump according to claim 10, characterized in that the liquid medium or the mixture of liquid medium and gas can be conveyed by the first and the second pump stage (13, 17), and that the first and the second pump stage (13, 17) each comprise a gear pump, wherein the two gear pumps can each be driven by a common drive shaft of the foam pump.

12. Foam pump according to claim 10, characterized in that the homogenization shaft (23) can also be driven by the common drive shaft of the two gear pumps of the foam pump.

13. Foam pump according to one or more of the preceding claims 11-12, characterized in that a gear (31 B) is arranged on the homogenization shaft (23), which meshes with and rotates together with a gear (31 A) of the gear pump of the first pumping stage (13) or the second pumping stage (17), which is mounted on a shaft (16) of the gear pump of the first or the second pumping stage (13, 17), in particular a shaft (16) common to both gear pumps of the first or the second pumping stage (13, 17).

14. Foam pump according to claim 13, characterized in that the gear (31 B) of the homogenizing shaft (23) rotates in a transmission ratio which lies in a transmission ratio interval of 1 :1 to 10:1, preferably 1.5:1 , to the meshing gear (31 A) of the first or second pump stage (13, 17).

15. Foam pump according to one or more of the preceding claims, characterized in that the homogenization shaft (23) is designed such that it does not convey the foam or the foamed mixture of liquid medium and gas.

16. Foam pump according to one or more of the preceding claims, characterized in that the homogenizing shaft (23) in the foam pump is guided parallel to the shaft (16) of the gear pump of the first and / or the second pump stage (13, 17), with whose gear (31 A) the gear (31 B) of the homogenizing shaft (23) meshes.

17. Foam pump according to one or more of the preceding claims, characterized in that the outer surface of the homogenizing shaft (23) and / or the shaft of one or each gear pump and / or one, several or each gear (15A, 15B, 19A, 19B, 31A, 31B) of the foam pump and / or the plates (11, 11') of the foam pump is / are surface-hardened, in particular by means of nitriding, carbonitriding, case hardening or titanium nitriding, and / or that the gears (15A, 15B, 19A, 19B, 31A) of one or each gear pump and / or the gear (31B) of the homogenizing shaft (23) is made of thermoplastic polymer.

18. Method for foaming liquid media using a foam pump, in particular a foam pump according to one or more of the preceding claims 1-17, wherein the liquid medium is drawn in by the foam pump, wherein the drawn-in liquid medium is mixed with gas to form a mixture and wherein the mixture is foamed in the foam pump, characterized in that the foam is conveyed in the foam pump through an elongated cavity (25) of a homogenization section (22) of the foam pump, bounded by a circumferential, in particular cylindrical, inner surface (27), for homogenizing the foam, in which a preferably rod-shaped homogenization shaft (23) having several homogenizing means (24) for homogenizing rotates and homogenizes the foam, in particular by reducing the size and / or size of gas bubbles in the foam.

19. Method for foaming liquid media according to claim 18, characterized by one or more features of claims 1 - 17. *****

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