DE3938306A1 - MIXING HEAD FOR FOAMING A SUBSTANCE WITH A GAS - Google Patents

Abstract

The description relates to a mixing head for foaming a substance with a gas, e.g. a dairy product with nitrogen. The mixing head has a rotor with coaxial circles of teeth arranged in radially and axially staggered array. The substance to be foamed thus passes through the mixing head both radially and axially, whereby the teeth of the circles arranged axially one behind the other can become finer with increasing proximity to the exit aperture. The mixing head is preferably formed in several stages, i.e. within a rotor/stator stage the toothed circles have the same axial position with no axial offset.

Description

The invention relates to a frothing mixing head, which a toothed rotor in a toothed stator housing points, and which supply openings for a gas and one Substance of a given viscosity and an outlet opening having.

Mixing heads of this type are used in many areas of tech nik used. A special area of application is Food processing technology, where thin to viscous Substances, such as dairy products, with nitrogen be foamed before they are packaged. By the The end product becomes particularly light and foaming loose, which increases the enjoyment when consumed.

In a known foam mixing head of this type the teeth of the rotor in several, in the circumferential direction running rows arranged radially outward and aligned in the axial direction, with all teeth have substantially the same size. The stator teeth are complementary to the rotor teeth arranged that rotor and stator during assembly in axis direction can be pushed into each other, and in loading the rotor teeth are axially offset between the rows of stator teeth.

Due to the system, the tooth width can be a maximum of one tooth distance correspond, so that the ratio of tooth width and tooth spacing for a number of applications is particularly cheap. Beyond that, it is not possible to adapt the frothing process to the fact that  the fabric first enters the mixing head different viscosity or consistency than when exiting points because the fine distribution with the gas on the input side is inevitably lower than on the output side.

The invention has for its object a To specify the frothing mixing head of the type mentioned at the outset, which is an arbitrary tooth width / tooth spacing ratio enables.

This object is achieved in that the rotor and Stator teeth aligned in opposite directions in the axial direction and radially and axially offset in several sprockets are arranged, the ring gear diameter on the input side is smaller than the output side.

The invention is based on the basic idea that at a axial alignment of the teeth joining rotor and stator independent of the tooth width and the tooth spacing pending, so that this in view of the are freely selectable. It also circulates speed of the sprockets with increasing diameter greater. In other words, this means that the circumferential ge speed increases along the flow path, so that the inevitably increasing amount of gas in the passage is associated with a higher circulation speed.

In principle, it is possible that each rotor / stator Sprocket in diameter from the adjacent sprocket below separates, d. that is, there is a paired association. Man gets essentially continuous in this way Lich expanding rotor / stator.

However, it is particularly advantageous if the rotor / stator at least two, preferably three, rotor / stator stages each has several sprockets, which in their  Axis position match d. H. which axially not ge are mutually offset. This has the advantage that in a ring gear labyrinth within each rotor / stator stage is generated, which leads to a particularly good foaming mung contributes.

The radial passage of the material to be foamed is especially supported by the fact that the interdental spaces of the individual ring gears within a stator stage and / or rotor stage are the same.

The gas distribution is supported by the fact that the Ver toothing of a rotor / stator stage compared to that in Flow direction previous stage is finer.

The cleaning of the mixing head and the maintenance an aseptic condition when used in the food industry rich is facilitated in that the rotor and / or the Stator are integrally formed.

Alternatively, it may be appropriate that the individual NEN rotor / stator stages are releasably connected.

In a particularly advantageous further development of the Erfin the feeds are arranged on the front and the The outlet opening is tangential.

The invention is based on a in the drawing voltage illustrated embodiment described further.

Fig. 1 shows schematically an axial longitudinal section through a three-stage foam mixing head and

FIG. 2 schematically shows a cross section through the frothing mixing head along the section line II-II in FIG. 1.

The foaming-mixing head, designated overall by 10 , has a rotor 11 and a stator housing 12 . A substance to be foamed is fed via a first feed opening 13 in an end face of the stator housing 12 . A gas is added via a second feed opening 14 in the same end face. The foamed end product is abge leads via a tangential outlet opening 15 .

In the example shown, the frothing-mixing head is constructed in three stages, ie the rotor 11 consists of a first, second and third rotor / stator stage 16 , 17 , 18 connected in series, which are connected to one another at least in a rotationally fixed manner on a shaft 19 are. Each of the rotor / stator stages 16 , 17 , 18 consists of a cylinder 20 , 21 or a disk 22 , on which, in the example shown here, in each case three sprockets 23 , 24 , 25 are arranged, which are coaxial with the shaft 19 in Direction to the two feed openings 13 , 14 are aligned.

The first rotor stage 16 assigned to the two feed openings 13 , 14 has the smallest diameter. The diameter of the two following rotor stages 17 , 18 is in each case larger by a predetermined amount in such a way that the associated ring gears 24 and 25 lie radially outside the cylinders 20 and 21 of the preceding first and second rotor stages 16 , 17 .

The ring gears 23 , 24 , 25 of the three rotor stages 16 , 17 , 18 are in engagement with complementary ring gears 26 , 27 , 28 which are arranged on the stator housing 12 . The figure shows that the stator housing 12 and the stator sprockets 26 , 27 , 28, in accordance with the gradation of the rotor 11, run in the same way in three stages, which expand outward in the direction of flow. During assembly or disassembly, the rotor 11 can therefore easily be pulled out of the stator housing 12 if a housing cover 29 is removed.

The flow of a substance to be foamed takes place according to arrow 30 initially in the radial direction through the first rotor / stator stage 16 . After passing through the outermost stator-side toothed ring, the material is guided into the second rotor stage 17 via a conically widening space 31 according to arrow 32 . A passage through the second and third stages 17 , 18 then takes place in the same way.

The rotor-side sprockets 24 , 25 of the second and third rotor stage 17 , 18 and the associated stator-side sprockets 27 , 28 are each finer compared to the sprockets 23 , 26 of the first rotor / stator stage 16 . With increasing mixing, the gas particle size is therefore refined, the circumferential speed also being increased compared to the previous stage due to the larger diameter.

In principle, it is also possible to provide the same diameter for the individual rotor / stator stages 16 , 17 , 18 . The material to be foamed is fed back inside after each step.

From the sectional view of FIG. 2 through the stator housing 12 along the section line II-II it can be seen that the tooth spaces 33 of the three stator-side sprockets 26 are substantially the same, so that radial straight straight passage channels are formed, wel che the radial Support the passage of fabric. The individual teeth are designated 35 .

Claims (8)

1. foaming-mixing head, which has a toothed rotor in a toothed stator housing, and which has feed openings for a gas and for a substance to be foamed, given viscosity and an outlet opening, characterized in that the rotor and stator teeth ( 35 ) aligned in opposite directions in the axial direction and are arranged radially and axially offset in a plurality of ring gears ( 23 to 28 ), the ring gear diameter being smaller on the input side than on the output side. 2. Mixing head according to claim 1, characterized in that 'the rotor ( 11 ) and the stator housing ( 12 ) has at least two rotor / stator stages ( 16 , 17 , 18 ), each with a plurality of ring gears ( 23 , 24 , 25 or 26 , 27 , 28 ) are provided, which coincide in their axis position. 3. Mixing head according to claim 2, characterized in that three rotor / stator stages ( 16 , 17 , 18 ) are present. 4. Mixing head according to one of the preceding claims, characterized in that the tooth spaces ( 33 ) of the individual toothed rings ( 23 to 28 ) within a rotor / stator stage ( 16 , 17 , 18 ) are essentially the same. 5. Mixing head according to one of claims 2 to 4, characterized in that the toothing of a rotor / stator stage ( 16 , 17 , 18 ) is finer in comparison to the previous stage in the flow direction. 6. Mixing head according to one of the preceding claims, characterized in that the rotor ( 11 ) and / or the stator housing ( 12 ) are integrally formed. 7. Mixing head according to one of claims 2 to 5, characterized in that the individual rotor and / or stator stages ( 16 , 17 , 18 ) are detachably connected to one another. 8. Mixing head according to one of the preceding claims, characterized in that the feeds ( 13 , 14 ) are arranged on the end face and the outlet opening ( 15 ) extends tangentially.