EP0760254B1 - Device for homogenising flowable materials - Google Patents

Description

• einen Behälter,
• wenigstens einen diesem Behälter zugeordneten Homogenisator,
• einen Zulauf für die Zuführung der Stoffe zum Homogenisator,
• einen Ablauf aus dem Homogenisator,
• eine absperrbare erste Verbindung zwischen dem Ablauf und dem Behälter, mittels der die Stoffe aus dem Ablauf in einen vom Homogenisator beabstandeten Bereich des Behälters rückführbar sind,
• eine zweite Verbindung zwischen dem Ablauf und dem Behälter, mittels der die Stoffe aus dem Ablauf in einen Bereich des Behälters zurückführbar sind, der einen geringeren Abstand vom Homogenisator aufweist als der Bereich, in dem die erste Verbindung in den Behälter mündet.

The invention relates to an invention for homogenizing flowable, in particular liquid or pasty substances, which comprises:

• a container,
• at least one homogenizer assigned to this container,
• an inlet for feeding the substances to the homogenizer,
• a sequence from the homogenizer,
• a lockable first connection between the drain and the container, by means of which the substances can be returned from the drain to a region of the container spaced from the homogenizer,
• a second connection between the outlet and the container, by means of which the substances can be returned from the outlet to an area of the container which is closer to the homogenizer than the area in which the first connection opens into the container.

Homogenization mixers are used in the pharmaceutical, cosmetic, chemical and food industry for the production of creams, ointments, Pastes, mayonnaises and similar products used. They have a mixing container on, usually at the bottom of the container a homogenizer for homogenizing and circulating the substances is arranged in the mixing container. The homogenizer is often designed as a rotor-stator dispersing machine, but can also be a circulation agitator to achieve a better pumping effect.

It is already known to design a homogenizing device so that the return of the material emerging from the outlet of the homogenizer into the mixing container either in the immediate vicinity of the homogenizer (usually on the tank bottom) or via a so-called circulation line in an upper area of the mixing container he follows. In the first case one speaks of a so-called homogenization in the boiler or mixing container and in the second case of a so-called homogenization in Circulation. Homogenization in the boiler is usually carried out when liquid or low-viscosity products can be homogenized. For higher viscosity products is usually homogenized in circulation, so that a regular shift of the entire boiler content takes place and a so-called product short-circuit over the Feed of the homogenizer is avoided.

EP-A 0 036 067 discloses a homogenizer in which the switchover between the two operating modes by means of an axially displaceable relative to the homogenizer Control ring takes place. The ring has two opposing sealing surfaces and closes the in the circulation line in its two axial end positions opening channel or the channel leading directly back to the boiler bottom. The each other channel is released. The Control ring is made by means of a single Hydraulic cylinder not described moved. This hydraulic cylinder must be placed in the area of the mechanically highly stressed homogenizer become. The arrangement of this hydraulic cylinder in the homogenizer and the necessary power transmission means Transferring the movement to the control ring means complication of the homogenizer structure and a weakening of its mechanical Resilience.

A generic homogenizing device is known from DE 28 05 942 C2. At this device is the discharge of the homogenizer via a throttle opening Annular gap connected to the bottom of the mixing container. With low viscosity Mixed material is fed back into the boiler through this throttle gap, it finds a place Homogenize in the boiler instead. If the mix has a higher viscosity during the mixing process friction in the throttle gap gradually leads to a blockage this gap, as a result of the then increasing pressure in the outlet, opens a sensor the bypass line, there is now homogenization in circulation.

This known device has various disadvantages. The one in the throttle gap Friction occurs increases the energy required for homogenization. A Defined process control is not possible, rather the operating states are established Homogenization in the boiler or homogenization in circulation independently depending on on the viscosity of the mix, transition states are also possible in which both types of homogenization take place simultaneously.

The invention has for its object a device of the type mentioned to create, which does not have the disadvantages mentioned or to a lesser extent.

The invention solves this problem in a device according to the preamble of the claim 1 in that the second connection has a closing device which when a predetermined pressure in the process is exceeded, this connection is released and it closes again when the pressure falls below a predetermined pressure.

The operation of the device according to the invention is as follows:

During the operation of the homogenizer, the mix is conveyed into the drain. When the lockable first connection is closed, the pressure in the drain increases long until a predetermined pressure is exceeded and the closing device second connection, which leads back to the container in a short way. It takes place then the so-called homogenization takes place in the boiler. The second connection is in the Usually end in the bottom of the container, but it can also be in other areas of the container that are located near the homogenizer inlet.

If the lockable first connection is opened, the mix can pass through this first Connection returned to the area of the container spaced from the homogenizer become. The pressure in the outlet consequently drops below a predetermined pressure, so that the closing device closes the second connection again. It is now taking place the so-called homogenization in circulation instead. According to the invention, it is therefore possible by simply opening or closing the barrier of the first connection To produce operating states of the homogenizer, so that an exact process control is possible. Since the opening or closing of the barrier is usually one causes a relatively large pressure drop or increase in the homogenizer process there is always a defined operating state of the device, in which either the the mixture is circulated first or via the second connection.

The cross section of the second connection is expedient within the scope of the invention chosen so that the product with a relatively high product viscosity relatively small friction losses flow through this second connection can. The friction losses occurring in the throttle gap in the prior art are avoided. Loss of pressure when passing through the second connection only to a small extent.

The closing device can be, for example, a valve that is in the process of a arranged pressure sensor is controlled. In the context of the invention, however, it is preferred that the closing device is acted upon by an external force in the closed position is biased. This external force is preferably a spring force. At a Pressure increase in the drain then the closing device against the spring force in it Open position pressed.

Different designs of the second connection are conceivable. As a rule, the second connection connect the drain of the homogenizer to the tank bottom. It is advantageously avoided that the second connection in the container in the area of the inlet of the homogenizer opens and thereby the inflow into the homogenizer disturbs. The second connection can be, for example, one or more of them Homogenizer housing and / or bore passing through the stator of the homogenizer or bores formed, which are preferably axially (parallel to the axis of rotation of the homogenizer) and the associated closing devices exhibit. However, it is particularly preferred to use the second connection as the outlet to form the ring channel connecting the inside of the container. For example, this Annular channel between the housing of the homogenizer and the stator or the stator cover be trained. The width of the ring channel is preferably dimensioned so that a low-friction and low-pressure passage even of relatively highly viscous Mixed material is possible. The ring channel opens in the preferred embodiment mentioned between the homogenizer housing and the stator cover in the area of the outer circumference of the homogenizer in the tank bottom, the return of the mixed material in the Containers in this area do not disturb the inflow into the homogenizer.

In the embodiment mentioned, the closing device is preferably as in the Area of the mouth of the ring channel formed in the drain arranged sealing ring, the spring loaded is biased into a closed position in which it is the ring channel sealed against the flow, and that when a predetermined value is exceeded Pressure in the drain against the spring force is movable into an open position in which it opens the ring channel towards the drain. In this embodiment of the invention is after closing the shutoff of the first connection and the subsequent pressure increase in the course of the homogenizer, a uniform discharge of mix into the Boiler possible over the entire circumference of the ring channel, so that the container contents is mixed evenly.

The first connection is usually designed as a circulation line, which is in the upper area of the container opens into this. With the help of this circulation line, it is possible, in particular Shift higher-viscosity products in the boiler to ensure that Even with these higher-viscosity products, uniform homogenization takes place.

In the context of the invention, a homogenizer is to be understood as any device a mixing and / or homogenizing effect using kinetic energy achieved. The homogenizer can be designed as a rotor-stator dispersion machine, which the kinetic energy of the rotor primarily through a strong swirl in Implemented dispersing effect and thus achieved an intensive homogenization. Based on these These rotor-stator dispersing machines only produce turbulence in proportion low pumping action, so that high drive energies may be required.

In the context of the invention it is also possible to use a rotor-stator dispersing machine instead to use a so-called circulation agitator as a homogenizer, that the kinetic energy of the rotor primarily in a pumping action and thus in Kinetic energy of the goods to be homogenized and only a low dispersing effect through swirling. Intermediate stages are also possible, for example conceivable to attach additional blades to the rotor of a rotor-stator dispersing machine, in order to improve the pumping action, as taken from DE-A-34 17 242 is known. Also the use of a homogenizer known from EP-B-0 290 033 is conceivable.

The use of a homogenizer with a higher pumping effect (circulation agitator) different compared to a rotor-stator dispersing machine with low pumping effect Benefits. Due to the high pumping speed of the circulation agitator can CIP cleaning the entire device without the aid of additional pumps be performed. The good pumping action allows the goods to be removed from the mixing device according to the invention in a second mixing container, while both the mixing device according to the invention and the second mixing container under reduced Pressure or vacuum. If only a rotor-stator dispersing machine with low pumping capacity, it may be necessary to support the Abförderns to aerate the mixing device from which is to be discharged. this in turn can lead to undesirable air pockets in the product to be homogenized to lead.

The possible high circulation rate when using homogenization in circulation A circulation agitator makes it possible to put smaller amounts of powder in the recycle stream suck in and thus feed the material to be homogenized.

Fig. 1

eine schematische Darstellung einer ersten Ausführungsform der erfindungsgemäßen Vorrichtung

Fig. 2

einen Querschnitt durch einen Teil des Mischbehälters und den Homogenisator;

Fig. 3

in einem vergrößerten Ausschnitt aus Fig. 2 einen teilweisen Querschnitt durch den als Rotor-Stator-Dispergiermaschine ausgebildeten Homogenisator;

Fig. 4

eine Fig. 1 entsprechende Darstellung einer zweiten Ausführungsform der Erfindung

Fig. 5

einen Querschnitt durch einen Teil des Mischbehälters und des Homogenisators dieser Ausführungsform;

Fig. 6

in einem vergrößerten Ausschnitt aus Fig. 5 einen teilweisen Querschnitt durch den als Umwälzrührwerk ausgebildeten Homogenisator;

Fig. 7

einen Querschnitt durch Rotor und Stator dieser Ausführungsform senkrecht zur Rotationsachse.

An embodiment of the invention is explained below with reference to the drawings. In it show:

Fig. 1

is a schematic representation of a first embodiment of the device according to the invention

Fig. 2

a cross section through part of the mixing container and the homogenizer;

Fig. 3

in an enlarged detail from FIG. 2, a partial cross section through the homogenizer designed as a rotor-stator dispersing machine;

Fig. 4

a representation corresponding to FIG. 1 of a second embodiment of the invention

Fig. 5

a cross section through part of the mixing container and the homogenizer of this embodiment;

Fig. 6

in an enlarged detail from FIG. 5, a partial cross section through the homogenizer designed as a circulating agitator;

Fig. 7

a cross section through the rotor and stator of this embodiment perpendicular to the axis of rotation.

First, the first embodiment will be described with reference to FIGS. 1 to 3.

The device according to the invention basically has a mixing container 1 and one homogenizer 2 driven by a drive 3. The at 4 in the inflow of Products entering the homogenizer can flow out of the homogenizer either through the ring channel to be described in more detail below back into the boiler are performed (homogenization in the boiler, indicated by the arrows at 5), or but led through the external circulation line 6 into the upper region of the mixing container 1 be so that the homogenization indicated by the arrows at 7 in circulation takes place. Shut-off valves 8, 9 are used to open or close the circulation line 6. After the homogenization has been completed, the product from the mixing container 1 to be discharged into a drain via the shut-off valve 10.

The structure of the homogenizer 2 can be seen more clearly in FIGS. 2 and 3. The drive 3 drives the shaft 11 with a shaft 12 provided with a hub 12 rotatably connected rotor 13, the two downward concentric to each other Rows of rotor teeth 14 and 15 has. With the homogenizer housing 16, the stator 17 is connected, the two mutually concentric rows of stator teeth 18, 19. A stator cover 20 connected to the stator 17 covers the rotor 13 on its outer circumference and at the same time forms the one labeled 21 Feed of the homogenizer. On the outer circumference of the homogenizer housing 16 is a concentric to the homogenizer shaft 22 is arranged, the drain of the homogenizer. As can be seen in FIG. 2, the channel 22 widens axial direction in the direction of rotation of the rotor 13 up to the connection of the outlet 22 with the circulation line 6. In the direction of rotation just behind the connection to the circulation line 6, the axial width of the outlet 22 narrows over a short circumferential section Use causes a large part of what is conveyed in the circumferential direction through the outlet 22 Mixed material exits into the circulation line 6 when the shut-off valve 8 and one the valves 9 or 10 are open. The said transition from the peripheral portion large axial width to the peripheral portion small axial width of the drain 22 is in Fig. 2 indicated at 23.

So far, this homogenizer corresponds to a conventional rotor-stator dispersion machine the state of the art. According to the invention is now between the homogenizer housing 16 and stator cover 20, an annular channel 24 is provided which Drain 22 connects to the product space of the mixing container 1. One of one indicated at 25 Spring device prestressed sealing ring 26 statically seals the ring channel 24 compared to the drain 22. It lies sealingly on a beveled surface 27 of the homogenizer housing 16.

When the homogenizer 2 is operating, the material contained in the container 1 is fed via the inlet 21 fed to the homogenizer 2. By rotating the homogenizer rotor is the product in a known manner with high forces (especially dispersing and Shear forces) and by the stator teeth 18,19 in the concentric to the rotor shaft 11 arranged annular drain channel 22 is pressed. Unless the valve 8 of the circulation line 6 is closed, the pressure in the outlet 22 rises until the Sealing ring 26 is raised against the force of the spring device 25 from its seat 27 is, so that the product from the outlet 22 through the ring channel 24 back into dei Container 1 can flow. In this operating state, the so-called mixing takes place in the Boiler instead (reference number 5 in Fig. 1).

When the valves 8 and 9 are opened, the product can flow from the outlet 22 into the Exit circulation line 6. The pressure in the outlet 22 drops so far that the spring device 25 presses the sealing ring 26 back onto its seat 27 and the ring channel 24 closes against the outlet 22. The product is now passed through the circulation line 6 pumped, the homogenization indicated by 7 in FIG. 1 takes place in circulation.

After the homogenization has been completed, the valve 9 is closed and the valves 8 and 10 open, the content of the mixing container 1 is then from the homogenizer 2 promoted in the process.

A second embodiment of the invention is shown in FIGS. 4 to 7. This embodiment largely corresponds to the first embodiment, therefore they are the same Parts with the same reference numerals. To that extent, the description of the first Embodiment referred. The differences from the first embodiment lie in the training of the homogenizer as a circulation agitator and in training and management the circulation line 6. These differences are described in more detail below.

6 and 7 it can be seen that the rotor 13 has conveyor blades 34 which in primarily designed to promote the goods to be homogenized in the drain 22 are and, unlike the first embodiment, only a relatively small one Apply shearing and dispersing action to this material. Accordingly, the rotational energy of the rotor 13 primarily in kinetic energy of the material to be homogenized Guts (pumping effect) implemented. The stator has guide surfaces or blades 35, to achieve a substantially laminar flow of the delivery vanes 34 funded assets are determined. These guide vanes 35 thus serve, unlike in a rotor-stator dispersing machine, not as baffles to achieve a dispersing effect.

The homogenizer 2 of this embodiment thus achieves a much higher one Pumping power as the rotor-stator dispersing machine of the first embodiment. Customized the circulation line 6 is also designed differently to this higher pumping capacity (see Figs. 4 and 5). Because of the achievable high circulation speed in the circulation line 6, powder can be sucked into the circulating stream via a valve 29 and so be mixed with the good. Additional liquid can be supplied via a valve 28 become. In normal circulation operation, the valve 30 is open and the valves 31 and 32 closed. By closing the valve 30 and opening the valve 32, the homogenized can Well, for example, can be fed to another mixing container. This is often required when the aqueous phase and the fat phase must first be mixed separately.

The high pumping action of the homogenizer 2 also enables CIP cleaning (cleaning in place) of the entire system without the aid of additional pumps. To for this purpose, cleaning liquid is introduced into the system and by means of the homogenizer 2 pumped through the circulation line 6. By opening the valve 31, the Cleaning liquid sprayed by means of a spray head 33 in the upper region of the container 1 and so moisten the entire inner surface of the container 1 evenly. The entire pipeline path can also be flushed in circulation.

Since there is no need for separate CIP systems and pumps, this makes it possible Embodiment of the invention a very significant cost saving.

Claims (8)

1. An apparatus for homogenising fluid substances, which has:

   a container (1),

   at least one homogeniser (2) associated with this container (1) and with an intake (21) for feeding the substances to the homogeniser (2),

   an outlet (22) from the homogeniser (2),

   a disconnectable first connection (6) between the outlet (22) and the container (1), by means of which the substances can be returned from the outlet (22) into a zone of the container (1) spaced apart from the homogeniser (2),

   a second connection (24) between the outlet (22) and the container (1), by means of which the substances can be returned from the outlet (22) into a zone of the container (1) which is at a smaller distance from the homogeniser (2) than the zone in which the first connection (6) discharges into the container,

   characterised in that the second connection (24) has a closing device (25,26) which, when a predetermined pressure in the outlet (22) is exceeded, releases this connection (24) and closes it again when the pressure falls below a predetermined level.
2. An apparatus according to Claim 1, characterised in that the closing device (25,26) is biased into the closed position acted upon by an external force.
3. An apparatus according to Claim 2, characterised in that this external force is a spring force.
4. An apparatus according to any one of Claims 1 to 3, characterised in that the second connection is in the form of an annular passage (24) connecting the outlet (22) to the inside of the container (1).
5. An apparatus according to Claim 4, characterised in that the closing device is in the form of a sealing ring (26) which is disposed in the vicinity of the opening of the annular passage (24) into the outlet (22) and which is biased under spring loading into a closed position, in which it closes the annular passage (24) with respect to the outlet (22), and which can be moved against the spring force into an open position when a predetermined pressure is exceeded in the outlet (22), so that the annular passage (24) opens towards the outlet (22).
6. An apparatus according to any one of Claims 1 to 5, characterised in that the first connection is in the form of a circulation duct (6) which discharges into the container (1) in the upper region thereof.
7. An apparatus according to any one of Claims 1 to 6, characterised in that the homogeniser (2) is in the form of a rotor-stator dispersion machine.
8. An apparatus according to any one of Claims 1 to 6, characterised in that the homogeniser (2) in the form of a circulation agitator.

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