DE202005006133U1 - Batch mixer for production of viscous emulsions, ointments and creams incorporates an external homogenizer - Google Patents

Abstract

A horizontal pressure vessel (2) has at least one agitator (6) rotatable about the major axis (4) to provide clearing of the cylindrical surface, and a rotor type homogenizer (8) with its inlet (8a) at the low point of the vessel and a spaced-apart discharge point back into the vessel. The vessel has a removable or hinged end door (16), and may be provided with a heating / cooling jacket.

Description

The The invention relates to a device for mixing and homogenizing viscous media, with a cylindrical or trough-shaped, horizontally arranged boiler, around its longitudinal axis inside the boiler a mixing element rotatably guided is.

Such a device is for example from the DE 37 28 710 A1 known, which describes a mixer with mixer and crusher.

The This invention relates in particular to the preparation of emulsions such as creams of relatively high viscosity, wherein an essential basic operation is homogenizing in one so-called homogenizer is performed.

Of the mixing tank or boiler containing the product to be homogenized and to that the homogenizer belongs to, is equipped with a mixing device, where essential tasks are: ensuring a uniform distribution of boiler contents and the material returned by the homogenizer; Heat supply and discharge; Stripping the boiler inner wall, in particular to avoid Incrustations and to improve the heat transfer; and exchange of the Boiler contents from bottom to top for improved degassing of the Product.

at the known device is a laterally in the cylindrical container wall stored comminutor or homogenizer provided, resulting in the Problem results that a Scraper, if in addition is provided, an annular area could not strip in the area of the crusher.

In addition, points the known device Pflugscharförmige mixing elements, the Mix the contents of the kettle without looking for an axial direction flow to care.

So far be for the production of emulsions, creams and ointments horizontal mixers not used, although their use compared to mixing devices vertically arranged boiler offers great advantages, such as a larger ratio of coat surface to volume and thus a better heat transfer; larger liquid surface and less liquid level (lower static pressure at the bottom and thus better degassing); lower height and thus much easier installation in existing buildings; lateral opening and thus easier access to the process space; possibility a two-sided storage of the agitator.

to appropriate use However, some requirements are met, so no disadvantages across from the vertical arrangement remain. These are in particular: good mixing by circulating flow, good drainability or low residue, and good cleanability.

The The object of the invention is therefore a generic device to improve that yourself (also) for the processing of viscous emulsions such as creams, etc. is suitable.

These The object is achieved by a Device for mixing and homogenizing viscous media dissolved, with a cylindrical or trough-shaped, horizontally arranged boiler, around its longitudinal axis inside the boiler a mixing element rotatably guided is, wherein the device is characterized in that under the boiler is arranged a homogenizer whose inlet with a Bottom of the boiler is connected and its outlet via a Umpumpleitung with a remote from the inlet point of the boiler is connected, wherein the mixing member a wiper member for stripping having the cylindrical inner wall of the boiler.

It can be provided that the Scraper for stripping the substantially entire inner surface the boiler is formed, i. both the cylindrical surface as also at least one of the frontal surfaces.

Prefers are several stripping elements offset in the circumferential direction and in Overlapping axial direction arranged.

The Scraper may have at least one hollow cylinder segment.

In preferred development of the invention is provided that the mixing element designed to generate a circulating flow within the boiler is.

The Mixing element may have at least one mixing coil.

Prefers is provided that the Mixing member for generating an axial flow in the direction of or is formed away from the homogenizer.

It can be provided that the Mixing element has at least two coaxial mixing elements.

The mixing element can be two opposing Have mixing elements.

The Mixing device may have two mixing elements, one of which a front side wall (cover) and another at one opposite front side wall (cover) can be arranged.

The Mixing elements can with independent Be provided drives.

Prefers is provided that the Boiler is tilted about a horizontal axis.

Conveniently, the boiler is provided with an overhead inspection opening, which is closed with a removable lid.

Prefers the invention provides that the boiler at least one to open frontal, having a vertical axis pivotable side wall.

Prefers is provided that the Boiler in the area of the homogenizer provided with a depression is.

Of the Homogenizer can be flanged directly to the boiler, about with his case, and without intermediate switching of an independent supply line.

It is advantageous if the boiler completely or partially double-walled is trained.

Conveniently, are arranged on the mixing element cleaning nozzles.

Further Advantages and features of the invention will become apparent from the following Description of exemplary embodiments, with reference to a drawing, in which

1 shows a schematic longitudinal section and an end view of a device according to the invention,

2 shows a cross-sectional shape of a cylindrical and a trough-shaped boiler,

3 and 4 each show a variant of a kettle tiltable about a horizontal axis,

5 shows a coaxial mixing element,

6 shows an embodiment with two agitators,

7 shows an embodiment with two opposing mixing elements arranged on a common shaft,

8th shows a perspective view of a support structure for a three-armed mixing element (anchor basket),

9 shows a schematic cross-sectional view, a side and a top view of a stripping element,

10 shows an example of a device with a boiler to be opened with a sidewall to be opened,

11 shows different arrangements of a pumping line, and

12 explains the arrangement of cleaning nozzles on a mixing device.

1 explains the basic structure of a device according to the invention, which is a horizontal, cylindrical vessel 2 with one about a longitudinal axis 4 the boiler rotatable, helical mixing element 6 and a homogenizer located below the kettle 8th having. The mixing organ 6 can be a continuous helical coil or multiple helical elements 41 each having an angular range of, for example, 240 ° extend and are arranged overlapping each other.

The cylindrical kettle 2 is at a first end with a fixed to the cylindrical outer wall 10 connected lid 12 closed while passing on the opposite side by one around a vertical axis 14 hinged and hinged 15 held lid 16 closed and accessible after its opening in its full cross-section. 10 shows a device according to the invention with the lid closed and opened, with a sight glass 17 is provided.

On the fixed lid 12 are a storage 20 for the mixing organ 6 as well as a drive 24 arranged.

The homogenizer 8th is with his intake 8a at a lowest point of the boiler 2 connected, for the purpose of a favorable processability of relatively viscous media an inlet 8a the homogenizer with the boiler connecting inlet line either deleted or kept very short, so that the product passes from the boiler on the shortest path in the homogenizer. For example, the homogenizer can be flanged with its housing directly to the boiler. In the example shown, the homogenizer in an axial end position of the boiler 2 arranged, however, may be advantageously arranged in the middle depending on the configuration of the boiler and the mixing element or agitator. The positioning shown is particularly favorable because with the lid open 16 a smooth inspection, maintenance, etc. of the homogenizer can be performed.

The kettle 2 resting on a relatively low frame 26 on the ground 28 , so that a problem-free accessibility of all essential parts without ladders, scaffolding, etc. is given, regardless of the length of the boiler. The boiler is in the area of its cylindrical middle section and the left cover 12 double-walled, with an inner wall with 2a and an outer wall with 2 B is designated.

Of the Boiler is vacuum-proof and within operational requirements formed pressure resistant. After homogenizing must by Evacuate frequently be degassed, so that a Void volume is useful in an upper area of the boiler. For this purpose, a dome can be placed in a conventional manner.

Even though the boiler basically be completely filled can be, a mode of operation with a partial filling of less than 90% of maximum filling preferably, in particular a partial filling between 70% and 80% the maximum filling.

at an operation with partial filling takes due to the geometric conditions, the ratio of heat-transfer area to volume significantly, this particular for a horizontal boiler applies, due to the relatively slimmer configuration of the filling material in relation to to a comparable vertical boiler.

There with decreasing filling level the specifically available stationary homogenizer performance increases, can and must be lower Fills to Ensuring product quality be produced faster. For keeping a desired one quality be the times for Homogenizing and cooling at the degree of filling customized.

The vessel is ideally cylindrical (cross-sectional shape "a"), but may also be designed as a trough (cross-sectional shape "b"), such as 2 shows. In this case, the filling height should be chosen so that product wetting is present only in a heated or cooled and stripped area.

to better drainability, the boiler can be easily tilted or tilted be arranged. A tiltability of up to 45 ° is favorable. In this case can the emptying over the homogenizer or laterally arranged bottom outlet guaranteed become.

3 and 4 show different variants of the support and pivotal mounting one about a horizontal axis 21 tiltable boiler. One with 23 indicated drive is the pivotal movement of the boiler.

The Mixing organ is wall-going and is equipped with scrapers. Basically, all known Mischorgangeometrien applicable, exemplifying an article by M. Kraume "Mixing and Stirring ", Wiley-VCH, 2003, referenced. Stripping elements are designated 44, wherein these axially and arranged offset in the circumferential direction along the mixing element are. Stripping elements are also preferred in the lid areas arranged.

Especially is appropriate a helical one Mixing organ ("helical ribbon ") on which one or more stripping elements are attached. Conveniently, causes the mixing device to a direction of rotation dependent product transport too one side of the boiler, resulting in a transport to the homogenizer out, or at the direction of rotation of this away, ensured can be.

Especially useful are mixing devices that cause a circulation of the product within the boiler. This can, for example, an external 40a and an inside one 40b Spiral or screw done, taking on 5 referenced. A change in the direction of rotation of the mixing element changes the flow direction of the product. Inside and outside spiral 40a, b have opposite directions of action. This causes not only a circulation but also a mild shearing of the product and thus mixing between adjacent fluid layers.

When turned counterclockwise, in 5 Seen from the left, the conveying effects and directions indicated by arrows are achieved. In the 5 right illustrated schematic frontal plan view symbolizes the spatial arrangement of the mixing helixes, wherein - seen from the left to the left - an increasing degree of blackening means a decreasing distance of the respective point of the helix of the (left of the device standing) viewer. The same applies to the illustration after 10 ,

Another advantageous embodiment includes a Koaxialrührwerk, ie, an outboard mixing element and lying on a separate shaft, coaxially arranged inner mixing element. The mixing elements can be of independent drives and be driven in the same or in opposite directions.

Thereby, that the Homogenizer is located below the boiler, stand both Kesseldeckelseiten available, a stirrer take. This gives you the opportunity two coaxial agitators to install, so that until to four separately driven mixing elements can be available.

6 shows a preferred variant, in which an outer, relatively slowly running mixing element (anchor with mixing helix (s)) 36 on the fixed lid 12 is arranged and a central, relatively fast-running second mixing element 38 (Mixing propeller with two or more wings) on the lid to be opened 16 is arranged. Both mixing elements have their own, separately controllable drives 24a . 24b Mistake.

If the homogenizer is located centrally or centrally below the vessel, and a directional mixing element such as a mixing helix is used, two helices should be fed from both sides towards the center 40 be provided, like 7 shows.

The support structure of the radially outwardly disposed mixing element, also referred to as anchor or anchor basket, requires at least one arm, for example two or three arms. For reasons of deflection in one-sided storage, it is advantageous to choose three circumferentially equally spaced arms, since the stiffness of an anchor is increased with a comparatively low material usage. 8th shows a perspective view of such an armature with three arms 42 , The inner surface of the boiler is indicated by circular contours. At one end (or both) of the anchor basket is stored in one or both lids of the boiler.

The necessary stripping elements are expediently designed such that she are easily replaceable. For The application should be in a horizontally lying ointment mixer they additionally in to be shaped that they Slightly idle in the vertical direction or the product easily expires.

A preferred variant of a stripping element 44 shows 9 above in the form of a depending on the direction of rotation differently inclined hollow cylinder segment. The stripping element 44 is preferably made of fluorinated plastic. The outer surface is preferably not machined to obtain the natural smoothness of the extrusion process. In a variant 44a a stripping element ( 9 , Middle and bottom) is the hollow cylinder segment with its axis 45 with respect to the boiler longitudinal axis 4 slightly inclined (angle α), wherein longitudinal edges of the stripping element are arcuately adapted to the boiler inner surface. In this way, the stripping elements support the directional effect of the mixing element.

When preferred material PVDF is used because the ideal geometry for the Holder is to represent by a thermal joining process. Preferably, several stripping elements are offset in the circumferential direction and overlapping each other in the axial direction, so that an overlapping Abstreifverhalten is achieved.

There due to the horizontal wave of the mixing element a certain Shaft deflection results are compared to the vertical boiler greater distances between Holm and scraper to consider. By a correspondingly wider selected scraper this can guaranteed with this characteristic also boilers with less precise roundness can be used.

The Sealing of the shaft of the mixer is as well as the seal the Homogenisatorwelle product contact. Depending on the application (fine chemistry, Food, cosmetics, pharmaceutical), the seal is designed differently, for example as radial shaft seal, product lubricated mechanical seal or double-acting mechanical seal with sealing medium.

If required, the at least one shaft of the mixing device can or be stored on both sides. A one-sided storage with below open basket (anchor) allows the use of additional agitators from the other side and facilitates the design of the lateral Cover.

11 explains different ways of arranging a pumping line 46 with which is prevented from the outlet 8b homogenized product coming from the homogenizer, re-enters the homogenizer in a short-circuited manner. Possible endpoints of the pumping line 46 are with 48 to 56 denotes, where 48 a short return near the homogenizer 8th designated, 52 a long return near the homogenizer, 54 a short return on the opposite side of the homogenizer and 56 a long return on the opposite side of the homogenizer.

It is advantageous if a short recirculation occurs at low fill levels. Particularly preferred is a short return such that they are central is arranged in a lower area of the boiler. advantageously, the feedback can be tangential lead, so that you the circulating flow supported.

To Achieve as much as possible complete discharge or a small amount of residue inside the boiler is next to it the measures already mentioned (Mixing element with conveying direction to the homogenizer, smooth wiper) favorable, if the mixing organ has a comparatively small surface. In addition, can the mixer itself provided with suitable scrapers and thereby to be cleaned from product.

Farther it can be cheap be, below the boiler in the area of the homogenizer a depression in the boiler casing and / or in the lid, so that the product preferably flows by itself to the homogenizer.

To clean the boiler and the entire device from the inside, it is possible to provide on-site installations in the boiler ("cleaning in place", CIP) .The cleaning takes place, for example, through nozzles arranged in the boiler jacket, which can be arranged such that they can be moved outwards Operation of the mixer and scrapers during production, or alternatively or additionally, nozzles 60 be provided on or in the mixing device, such as 12 shows, so that an ideal approach of the cleaning liquid to all desired positions is possible. The mixing element is at least partially designed as a hollow profile. The supply takes place via a central shaft 22 , The nozzles can be extendable.

Further can be provided, cleaning heads through a cover page through cleaning holes in the lid or after opening the lid.

The entire arrangement is preferred by a programmable logic Control regulated. Sensors for Pressure, temperature, flow, pH, Particle size and / or other product characteristics give the required input signals.

basics Advantages of the present invention are: good mixing; large heat transfer area and short process times; low height (Installation in low building possible); loss of elaborate Deckelhubeinrichtungen (required for vertical Boiler); easy access to the homogenizer for inspections; good degassing (size Surface); no stage; easy product feed and two-way access and resulting size variability for the Construction of the mixing device.

2

boiler

2a

inner wall

2 B

outer wall

4

longitudinal axis

6

mixing member

8th

homogenizer

8a

Inlet

8b

outlet

10

outer wall

12

cover (Side wall)

14

swivel axis

15

hinge

16

cover (Side wall)

17

sight glass

20

storage

21

axis

22

wave

23

Rotary actuator

24

drive

24a, 24b

drive

26

frame

28

ground

36

first mixing element

38

second mixing element

40

mixing shaft

40a

internal spiral

40b

external spiral

41

spiral element

42

poor

44

stripping element

44a

obliquely positioned stripping element

45

axis

46

recirculating

48

short return

52

Long return

54

short return

56

Long return

α

angle

Claims (19)

Device for mixing and homogenizing viscous media, with a cylindrical or pressure-shaped, horizontally arranged vessel ( 2 ), about its longitudinal axis ( 4 ) inside the boiler ( 2 ) a mixing element ( 6 ) is rotatably guided, characterized in that under the boiler ( 2 ) a homogenizer ( 8th ) whose inlet ( 8a ) with a bottom of the boiler ( 2 ) and its outlet ( 8b ) via a pumping line ( 46 ) with one of the inlet ( 8a ) remote point of the boiler ( 2 ), the mixing element ( 6 ) a scraper ( 44 ) for stripping the cylindrical inner wall of the boiler ( 2 ) having. Apparatus according to claim 1, characterized in that the wiper member ( 44 ) for stripping the entire inner surface of the kes sels ( 2 ) is trained. Apparatus according to claim 1 or 2, characterized in that a plurality of stripping elements ( 44 ) offset in the circumferential direction and are arranged overlapping each other in the axial direction. Device according to one of the preceding claims, characterized characterized in that Scraper having at least one hollow cylinder segment. Device according to one of the preceding claims, characterized in that the wiper member ( 44 ) at least one opposite the longitudinal axis ( 4 ) of the boiler ( 2 ) inclined Abstreifelement ( 44 ) having. Device according to one of the preceding claims, characterized in that the mixing element ( 6 ) for generating a circulating flow within the boiler ( 2 ) is trained. Device according to one of the preceding claims, characterized in that the mixing element ( 6 ) at least one mixing helix ( 40 ) having. Device according to one of the preceding claims, characterized in that the mixing element ( 6 ) for generating an axial flow in the direction of or away from the homogenizer. Device according to one of the preceding claims, characterized in that the mixing element ( 6 ) at least two coxial mixing elements ( 36 . 38 ) having. Device according to one of the preceding claims, characterized in that the mixing element ( 6 ) has two opposing mixing elements. Device according to one of the preceding claims, characterized in that the mixing element ( 6 ) has two mixing elements, one of which on a front side wall ( 12 ) and another on an opposite front side wall ( 16 ) is arranged. Device according to one of claims 9 to 11, characterized that the Mixing elements have at least two independent drives. Device according to one of the preceding claims, characterized in that the boiler ( 2 ) is tilted about a horizontal axis. Device according to one of the preceding claims, characterized characterized in that Boiler is provided with an overhead inspection opening, which with a removable lid is closed. Device according to one of the preceding claims, characterized in that the boiler ( 2 ) at least one front-side, to a vertical axis pivotable side wall (cover) ( 12 . 16 ) having. Device according to one of the preceding claims, characterized in that the boiler ( 2 ) in the region of the homogenizer ( 8th ) is provided with a recess. Device according to one of the preceding claims, characterized in that the boiler ( 2 ) is formed completely or partially double-walled in its cylindrical or trough-shaped area. Device according to claim 17, characterized in that one or both covers ( 12 . 16 ) are double-walled. Device according to one of the preceding claims, characterized in that on or in the mixing device ( 6 ) Cleaning nozzles ( 60 ) are arranged.