EP0896833B1 - Device for homogenizing flowable materials - Google Patents

Description

The invention relates to a device for homogenizing flowable Substances, in particular mayonnaises, emulsions, ointments, Creams and the like, the viscosity of which may change during of homogenization changes, with a mixing container, an am Container arranged homogenizer, an inlet for the feed the substances from the mixing container to the homogenizer and one Drain from the homogenizer, which is connected to the Mixing container communicates.

Generic homogenizers are for example known from DE-PS 28 05 942. Usually the Homogenizer arranged in the bottom area of the mixing container that the inlet and outlet of the homogenizer in the bottom area of the mixing kettle open relatively close together. In addition, preferably a circulation line or bypass line is provided, from the drain of the homogenizer in the upper area of the Mixing container leads. The circulation line or bypass line is then executed lockable.

Such homogenizers allow two different homogenizers, known as "homogenizing in the mixing container" and "homogenizing in circulation or during emptying".

In the first case, the homogenized is returned from Mixing material emerging from the outlet of the homogenizer into the mixing container relatively close to the homogenizer feed, especially in the Area of the tank bottom. In the second case, this is homogenized Well returned to the top of the mixing bowl.

The choice between these two modes of operation allows it, influences the product viscosity, which changes in the course of homogenization can also change greatly, and other influences too take into account the specific mixing task put.

In the manufacture of pasty products such as creams, lotions, Ointments, mayonnaises and the like mostly become the raw materials presented in the liquid state; if necessary, they become this Purpose melted. These raw materials are in the in most cases thin at high temperatures. Often they have to applied with high mixing intensity in the fluid state be, for example, agglomerate-free suspensions or to achieve the finest emulsion droplets. The product viscosity often increases due to homogenization and can do a lot to increase drastically.

Basically, this also depends on the degree of filling of the mixing container, up to product viscosities of approximately 5000 mPas homogenization in the mixing container. The viscosity is then still low enough to redeploy the contents of the mixer ensure and avoid that product mixture from the end of the Homogenizer immediately flows back to the inlet (so-called "Product short circuit").

At higher viscosities, but again depending on the level in the mixing tank, you choose the homogenization in circulation, to force a redistribution of the entire boiler contents and Avoid product short circuits.

In the homogenizer according to DE-PS 28 05 942, the "direct" connection between the run of the homogenizer and the mixing container bottom an annular gap in the bottom of the Mixing container forms a throttle opening. When "homogenizing in Mixing container "is the correspondingly low-viscosity mix, with correspondingly relatively low resistance through which Throttle gap returned to the mixing tank. Increases during the mixing of the product viscosity results from the Adhesion of the product to the walls of the throttle gap correspondingly higher resistance in the gap. Exceeds this Resistance a limit that is about a product viscosity of corresponds to around 5000 mPas, then the otherwise blocked circulation line opened, and the product instead of to the bottom of the mixing container led to its upper area. Now homogenization takes place in circulation, so that a complete record the mix is guaranteed. Switching to homogenization in the circulation process is done manually, by opening of valves, or also pressure-dependent by sensors.

Such homogenizers are very different Machine sizes executed; the container contents vary for example between 15 l and 10,000 1. Different machine types have differently powerful homogenizers different geometries. Depending on the line size, number of the bends, valves etc. also vary the delivery resistances the circulation lines. It must always be ensured that the necessary homogenization operation actually takes place, in particular, therefore, that from a certain product viscosity, if the circulation line is opened, product promotion and homogenization actually at least almost exclusively via the circulation line takes place.

To achieve this, DE-OS 195 37 303 proposes the annular gap that connects the homogenizer drain and forms the mixing container, also lockable train. For this purpose, according to DE-OS 195 37 303, preferably one Closing device provided in the connection, the one has spring-loaded sealing element. For example the connection as an annular channel between the outlet of the homogenizer and the interior of the mixing container are formed, wherein then the closing device should be a sealing ring which in the Mouth of the ring channel is arranged. The sealing ring is through a spring pushed into its closed position, in which he the Closes the circular channel from the drain. With one The embodiment is the opening, that is, the release of the second Connection for homogenizing in the mixing tank, depending on the spring force.

The operating state "homogenization in the circulation process" should also according to DE-OS 195 37 303, can be selected in that the barrier the first connection between the homogenizer drain and Mixing container is opened. As long as the first connection that Circulation line, is open, the second connection through the Closing device must be closed.

For products with high viscosity, for which the homogenization in Circulation procedure is just required, must in the course of the Homogenizer such a high pressure that the line resistances be overcome in circulation. Is the pressure in the drain too low, the line resistances in circulation act like the shut-off, i.e. the first connection is effectively closed. now are the line resistance in circulation is quite considerable. At high Product viscosities, above 5000 and up to about 100000 mPas through valves, pipe bends, pipe cross-sections, but also due to the substantial adhesion of the product to pipe walls, large Line resistances. The line resistance in circulation can be without correspond to another 2 bar overpressure. The locking device switches (by opening) to the wrong homogenization mode just then (in the mixing container) if this is because of the very high viscosity of the mixed material is the least questionable; and the earlier, the lower the spring pressure. So would have to to achieve the goal of DE-OS 195 37 303 at all, the closing device in the second connection, between the homogenizer process and the mixing tank bottom, even at such high Pressures remain closed as they are necessary to keep the Line resistance in circulation also with highly viscous mix overcome. For example, the proposed spring loaded Sealing ring device in the ring channel the corresponding Springs are designed so strong that they are always larger Apply force than is necessary to reduce the line resistance in the To overcome circulation. However, this necessarily means that the other operating mode, namely homogenizing in the mixing vessel, is only possible when the circulation is blocked, because the closed one Closing device in the second connection against this high spring pressure would have to be opened. Even then, in addition, a very high pumping power of the homogenizer is required, to open the closing device.

This makes it when working with the homogenizer at low speed, and correspondingly low pressure build-up in the drain, but impossible, to operate the device. For example, foaming products in which no air is homogenized should then no longer process at all.

However, if you decrease the spring force to avoid this problem, the closing device no longer closes. The arrangement of the sealing ring and directional channel then corresponds functionally the throttle gap known from DE-OS 28 05 942.

The device according to DE-OS 195 37 303 can therefore be fundamentally only operate if there are sufficient quantities of mix at high Speed of the homogenizer, i.e. processed at high capacity can be. With increasing product viscosity in mixed operation then there is an increasing increase in resistance in the closing device, which is functionally a throttle gap completely corresponds. Switching inevitably occurs homogenization in circulation, with simultaneous product short-circuit over the second connection.

So while the device according to DE-OS 195 37 303 the desired The intended closing device does not achieve the intended purpose as a rule to significant problems of a different kind that Devices with throttle gap do not occur. In particular, this concerns the cleaning of the mixing container. If by distance of the mix and rinsing the container with cleaning solution and the like when the drain is depressurized, the locking device actually closing as intended is a complete one The mixing container cannot be emptied after cleaning. The (second) connection between the drain and The bottom of the container is closed because the homogenizer has no pressure can build more if air is sucked in when largely emptied is so that there is washing water above the locking device accumulates, which the homogenizer cannot pump out. This can result in considerable contamination. That in the DE-OS 195 37 303 provided "cleaning in place", which the The pump effect of the homogenizer is to be exploited by the provided locking device made impossible.

There are no clear statements in the prior art that the geometry of the annular gap in such homogenizers correlate with product viscosity and flow behavior.

Against this background, it is an essential task of the Invention to design generic homogenizers so that with simple means even with very different Machine sizes, homogenizer performance, etc. definitive setting of the required homogenizing operation allow.

In particular, it is an essential object of the invention generic homogenizers with simple means so to design that ensured even with high product viscosities is that with the circulation line open, the product promotion and homogenization at least almost exclusively via the circulation line.

These tasks are carried out with a device with the Features of claim 1 solved.

The invention is based on the idea of generic Homogenizers with circulation line by choice of certain Geometries for the annular gap in the homogenization operation as described in the beginning is explained, depending on the viscosity of the product set.

Thus, according to the invention, a generic device is designed that the annular gap has a gap length L and a gap width S has, which are dimensioned so that the ratio L / S maximum is about 160 if the gap width S is greater than 0.5 mm and / or the gap length L is greater than 30 mm.

Another definition of the invention is for the ratio L / S set a minimum value of more than 60; this concerns also geometries with gap widths S ≤ 0.5 mm and / or gap lengths L ≤ 30 mm.

The subclaims define advantageous configurations of the Invention. Such gap geometries are in particular according to the invention preferred, in which the gap width S between 0.55 mm and 1.5 mm, with the gap width usually being between 0.7 mm and will choose 1.5 mm. The gap width S is particularly preferably at about 1 mm.

The gap length L can be relatively large, between about 5 mm and about Vary 100 mm; it is not excluded that the gap length can also be larger than 100 mm. But in particular lies the Gap length between 8 mm and 80 mm, preferably between 20 mm and 80 mm. A gap length of is currently particularly preferred about 70 mm.

The most preferred ratio of L / S lies at around 80.

The annular gap need not have a constant gap width in the course of Have gap length. Rather, it is quite advantageous that the gap width changes over the gap length. Through that associated speed changes of the product in the gap can the resistance values and thus the viscosity-dependent Adhesion and flow behavior of the product strongly influenced in the gap and be optimized.

For example, this can be realized by how is preferred according to the invention in the region of the annular gap radial at least one of the components defining the annular gap Steps or shoulders are provided over the gap length of the Define ring gaps distributed areas of different gap width. This is followed by sections in which those defining the gap Walls are radially closer to each other, in areas where these walls are further apart, so that over the Length of the annular gap chambers of larger volume and narrowing points take turns in which the product is significantly faster must flow, and is sheared more.

The use of these measures is particularly advantageous in such cases Homogenizers that have a lockable circulation or Bypass line, the shut-off valve depending Automatically actuated by pressure in the outlet under sensor control is.

Figur 1

einen schematischen Querschnitt durch eine erfindungsgemäße Homogenisiervorrichtung, ausgehend von der in der DE-PS 28 05 942 beschriebenen Vorrichtung, und

Figuren 2a bis 2c

verschiedene erfindungsgemäße Spaltgeometrien.

The invention is explained in more detail below with the aid of the attached figure. In it show:

Figure 1

a schematic cross section through a homogenizing device according to the invention, starting from the device described in DE-PS 28 05 942, and

Figures 2a to 2c

different gap geometries according to the invention.

The homogenizing mixer 10 shown in FIG. 1 comprises a mixing container 11, on the bottom 11a of a gyro homogenizer 14 with an inlet 12 and an outlet 13 is fixed. The Drain 13 of the gyro homogenizer 14 is via a three-way valve 15 with one in the upper region of the mixing container 11 leading circulation line 16 connected. On the other hand, the Drain 13 via the three-way valve 15 with a drain line 17th connected.

The outlet 13 of the gyro homogenizer 14 is through an annular gap 18 connected to the mixing container 11. Also closes directly at the outlet 13, a shut-off valve 19, which means an automatic drive 21, depending on the pressure in Process 13 is actuated; the pressure is measured by a sensor 20 detected that protrudes into the process 13. The sensor 20 controls the automatic drive 21. The shut-off valve 19 can also be operated manually be operated.

In operation, the low-viscosity mix contents are from the gyro homogenizer 14 via the inlet 12 from the mixing container 11 sucked. The gyro homogenizer 14 conveys this mix, depending after the shut-off valve 19, either over the annular gap 18 back into the bottom area of the mixing container, or over the circulation line 16 in the upper region of the mixing container.

As long as the viscosity of the mix allows this, i.e. low is enough, the homogenization takes place in the container, whereby the Mixture from the annular gap 18 at a relatively high speed and relatively low throughput. The high exit speed contributes to the intensive mixing of the mixing container contents at. This intensive mixing results even with low filling of the mixing container 11. Because of the relative low throughput results in an intensive mixing and crushing effect in the gyro homogenizer itself.

In the case of the annular gap 18 according to FIGS. 1 and 2, the ratio is total gap length to the gap width according to the invention a maximum of about 160. In such Embodiments is in particular the gap width S on average about 1 mm and the gap length L in total about 70 mm.

In the embodiment of the invention shown in FIG Annular gap defined by the outer wall of the homogenizer stator on the one hand, and the homogenizer housing on the other hand, which here integrally attached to the container bottom 11a. With the preferred The embodiment according to FIG. 2a is the inner surface of the housing provided with ring grooves that cause the ring gap to in the direction of flow, alternately expanded and narrowed again.

In Figure 2b, these grooves are instead on the outside of the Stator provided, but have exactly the same effect.

FIG. 2c shows an embodiment in which corresponding grooves and thus radial steps or shoulders, provided in both components are.

In the cited cases according to FIGS. 2a to 2c, the total length of the annular gap consists of several gap length ranges L1, L2 ... in which the gap width S1, S2 ... is different in each case. For the dimensioning of the ratio of gap length to gap width in the sense according to the invention, the gap length is then added up from all gap length ranges, where: L / S = (L1 / S1 + L2 / S2 + ...).

Such gap geometries are also suitable for devices which the gap width S ≥ 0.5 mm and / or the gap length L ≥ 30 mm. According to the invention it is provided that the ratio L / S, possibly composed of parts L1 / S1, L2 / S2 etc, is greater than 60.

In the most preferred embodiments of the invention is the ratio L / S, possibly composed Individual contributions with different gap widths as defined above, around 80 ± 3. For example, it is currently one preferred embodiment, with a gap width of about 1 mm and a gap length of about 70 mm, at 70.

In practice, the geometry of the annular gap will be coordinated with the other machine parameters. Doing so the mixing tank size, the dimensions of the circulation line (if available), and the performance as well as the geometry of the homogenizer.

It is definitely planned to use existing machines retrofit accordingly.

Claims (8)

1. Device for homogenising materials which are capable of flowing, in particular of mayonnaise, emulsions, ointments, creams or the like, the viscosity of which changes during the homogenisation, with a mixing vessel (11), an homogenizer (14) arranged at the vessel (11), a supply (12) for supplying materials from the mixing vessel (11) to the homogenizer (14) and a drain (13) leaving the homogenizer (14) which communicates with the mixing vessel (11) via an annular gap (18),
   characterised in that the annular gap (18) has a gap length L and a gap width S, for which the ratio L/S: 60 < L/S ≤ 160 is fulfilled.
2. Device according to claim 1,
   characterised in that the gap width S is between 0.55 mm and 2.5 mm, preferably between 0.7 mm and 1.5 mm and more preferably approximately 1 mm.
3. Device according to claim 1 or 2,
   characterised in that the gap length L is between 5 mm and 100 mm, in particular between 8 mm and 80 mm and preferably between 20 mm and 80 mm and in particular preferably approximately 70 mm.
4. Device according to one of claims 1 to 3,
   characterised in that the ratio L/S is approximately 80.
5. Device according to one of claims 1 to 4,
   characterised in that the annular gap (18) has at least two gap length regions (L1, L2...) having different gap widths (S1, S2 ...), wherein: L/S = (L1/S1 + L2/S2 + ...).
6. Device according to one of the preceding claims,
   characterised in that a drain pipe (17) is provided for the materials from the device, which may be shut off, wherein the drain (13) from the homogenizer (14) is connectable to the drain pipe (17) and wherein the shutoff of the drain pipe (17) is accomplished by means of a blocking valve (19) arranged therein.
7. Device according to claim 6,
   characterised in that an end of a bypass pipe (16) is connected to the drain pipe (17) after the blocking valve (19) and another end to the upper region of the mixing vessel (11) and that a three-way valve (15) or respective individual blocking valves are arranged in between.
8. Device according to claim 7,
   characterised in that the blocking valve (19) may be actuated by means of an automatic drive (21) controlled by a sensor (20) in correspondence to the viscosity of the product in the drain (13).

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