EP2080549A2 - Stirring organ and stirring assembly for mixing and/or homogenisation of flowable media - Google Patents

Abstract

Stirring device comprises a tubular body (1) with side walls (1.1, 1.2, 1.3, 1.4) forming a bend or polygonal progression. Preferred Features: The tubular body has a rectangular cross-section. The side wall (1.3) is planar in relation to the side wall (1.1) and has the shape of a trapezium having parallel side edges forming a side edge of an inlet opening (2) and an outlet opening (3).

Description

The invention relates to an agitator of an agitator for mixing and / or homogenizing fluid media having the features according to the preamble of claim 1. Furthermore, the invention relates to an agitator for mixing and / or homogenizing fluid media with at least two such Rührorganen.

Agitators are used in a wide variety of applications. Examples of possible fields of application include the production of paints and varnishes or the production of beverages and foodstuffs. Also in the production of pharmaceutical products and cosmetics it regularly requires the use of agitators, so also in the paper and ceramic production. Depending on the particular field of application, different agitator arrangements are used for mixing and / or homogenizing the respective substances. Known are, for example, drum and container stirrers, which are arranged in or on the respective container, or self-supporting tripod stirrers. Even small to large-volume containers for storage or for the transport of mixtures may be equipped with a stirrer to prevent segregation during storage or transport. The agitator is adapted to the respective material to be stirred and the shape and size of the respective container.

Stirrers usually comprise a motor driven shaft, by means of which one or more rotatably connected to the shaft agitators are moved in a circular path. Used in a container with a flowable medium, the stirring elements are flowed around because of their movement of the medium. Depending on the shape of the stirrers, their arrangement in the container and the speed at which the stirrers are moved, set in the mix certain flow conditions, which cause a mixing of the material to be stirred.

There are stirrers are known, the betriebewuverden at high speeds to achieve the desired mixing effect by turbulence of the material to be stirred. This can lead to air intake and / or foaming, which are undesirable in certain applications. This is the case, for example, in the production of paints or in the production of ceramics. High speeds, especially in combination with sharp-edged stirring elements, can also cause shear forces that can damage impact and shear-sensitive mixtures. The sensitive substance mixtures often include certain foods or biochemical products. By adding certain color pigments, color mixtures can also have such a sensitivity. The associated with the high speeds usually high flow rates can also lead to a heating of the material to be stirred. When mixing and / or homogenizing temperature-sensitive mixtures, however, it is necessary to avoid such heating. At least in the abovementioned cases, it is necessary to use a substance-sparing stirring method and a corresponding stirring device which enables effective mixing of the material to be stirred even at low speeds.

From the DE 39 01 894 A1 An agitator is known which enables a complete mixing of a flowable medium at a relatively low speed of movement of the stirring elements. It is therefore also more sensitive to treatment Substance mixtures suitable. The low speed of movement of the stirring means causes countercurrents to form in the mixture, which promote the mixing effect. The stirring times can even be shortened. Low drive power and short stirring times also lead to a reduction in the required energy consumption. The agitator described comprises a shaft with arms extending perpendicular to the longitudinal axis of the shaft, each carrying a stirrer with a conically extending pipe section. The cross section of the conical tube section narrows in the opposite direction to the direction of rotation, ie in the direction of flow. The inlet opening for the flowing through material is thus greater than the outlet opening. The longitudinal axis of the conical tube section is also placed obliquely downwards in the direction of rotation. The concrete design and arrangement of the stirring elements and their low speed of movement to cause flow conditions that allow a wide-ranging detection of the material to be stirred and thus an effective and efficient mixing.

Tubular bodies having an inlet opening and an outlet opening for a flowable medium are also known from other areas of the art. For example, shows the US 1,012,308 A a propeller with a conically extending tubular body, wherein the inlet opening is larger than the outlet opening.

An at least partial constriction in the direction of flow also has the stirring element of the US 5,156,778 A on. The constriction is formed within a pipe section by at least one arcuately extending side wall.

Based on the above-described prior art, it is an object of the present invention to further develop a generic agitator, in particular the stirring elements of such a stirrer, so that complete mixing of the material to be stirred can be achieved even more efficiently.

The object is achieved by a stirrer having the features of claim 1. Preferred concrete embodiments of the stirrer are described in the subclaims. In addition, the object is achieved by an agitator with at least two such stirring elements.

According to the invention, the stirring element with the features of the preamble of claim 1 has a four-sided walls tubular body, of which at least one has a curved or polygonal course in longitudinal section. The arcuate or polygonal extending side wall is preferably located outside with respect to the circular path along which the stirring member is moved. In other words, this side wall is the closest to the inner wall of the container receiving the stirring material. Preferably, the begebförmige or polygonal course of the side wall is adapted to the course of the container inner wall such that the stirring material located in the intermediate space is completely detected and included in the stirring process. In an agitator moving along a circular path, an arcuate or polygon-like course of a side wall also has a positive effect on the flow conditions prevailing on the agitator, provided that the arcuate or polygon-like sidewall follows a circular line substantially concentric with the circular path. Because of this measure, the tubular body is given a streamlined shape and can be moved more easily through the stirring material due to the reduced flow resistance. This makes it possible to save drive energy and thus to operate an efficient stirring process.

According to a preferred embodiment, the tubular body of the stirring member has a rectangular cross-sectional shape. Starting from a rectangular cross-sectional shape in the region of the inlet opening, the cross-sectional shape can change in the length development of the tubular body. Preferably, however, all four side walls are perpendicular to each other.

Further preferably, the side wall opposite the arcuate or polygonal pull side wall is flat and has the shape of a trapezoid. The two parallel side edges of the trapezium each form a side edge of the inlet opening and the outlet opening. At the other two side edges of the trapezoid, two more side walls connect.

Preferably, the side wall opposite the arcuate or polygonal-shaped side wall has the shape of an isosceles trapezium. The two inner angles at the long parallel side edge are 70 ° - 80 °, preferably 76 °. The tubular body thus has a narrowing cross-section. In this case, the inlet opening for the medium flowing through is larger than the outlet opening.

The preferably made of a metallic material side walls of the tubular body are welded together along their longitudinal edges. The weld gives the pipe body a sufficient stability. Other materials which can be welded together can also be provided as material for the tubular body.

The agitator according to the invention for mixing and / or homogenizing fluid media comprises a drivable shaft and at least two stirring elements according to the invention, wherein each stirring element is connected via a support arm in the direction of rotation fixed to the shaft. The shaft can preferably be driven by an electric motor, so that each stirring element fastened on the outside of a support arm can be moved along a circular path concentric to the shaft longitudinal axis. The agitator preferably has one or two pairs of stirring elements lying opposite one another, which are each arranged on a common support arm. In a pair of stirrers, the support arm preferably has a low overall height in the direction of the shaft axis in order to reduce the flow resistance at the corresponding side surfaces.

In each case two Rührorganpaaren the support arms can be arranged crosswise. To attach the stirring elements to the shaft, a sleeve is preferably arranged at the intersection of the intersecting support arms or in the center of a support arm, by means of which the stirring elements can preferably be connected via a screw connection with the shaft. In addition, the attachment of the stirring elements on the shaft can also be effected via a plug connection, as far as a rotationally fixed connection, at least in the direction of rotation of the shaft, is ensured.

A screw or plug connection for attachment of the stirring elements on the shaft of a stirrer should be solvable to allow the replacement of the stirring elements. Depending on the nature of the material to be stirred or the size of the container, the agitator or the stirring elements can then be matched to the particular application in terms of their concrete shape, size or number.

Depending on the application, it may be necessary for the stirring elements to be introduced into a container. If the container has only a small opening, it may be advantageous if each stirring element is connected to the shaft via a hinged and / or pivotable support arm. The support arms are pivoted for insertion of the stirring elements in the container in an orientation parallel to the shaft longitudinal axis and thereby brought together the stirring elements. In this way, the discharge of the agitator can be reduced, so that the introduction of the stirring elements is also possible through small openings. The provision of the stirring elements is due to the centrifugal forces with commissioning of the agitator independently. In addition, return mechanisms may be provided, for example, springs, which support a provision of the stirring elements.

Preferably, each support arm made of a metallic material, such as a flat steel, which is attached via a welded connection to the stirring elements in order to ensure the necessary stability.

According to a preferred embodiment, the stirring elements of an operating agitator are arranged rotationally symmetrically at the same distance from each other. All stirrers move on the same circular path.

Of the four side walls, which make up each stirrer, at least one side wall is aligned substantially parallel to the shaft longitudinal axis during operation of the stirrer. If all four side walls are perpendicular to one another, the inlet or outlet opening of the stirring element has a horizontal or standing rectangular cross-section. During operation of the agitator, the longitudinal axis of a support arm is furthermore preferably aligned substantially perpendicular to the longitudinal axis of the shaft. Further preferably, the side wall connected to the support arm and preferably aligned parallel to the shaft longitudinal axis relative to the longitudinal axis of the support arm has an angle of incidence of 40 ° to 50 °, preferably 45 °. The angle of attack of this side wall causes the inlet opening has a larger cross-section than the outlet opening of the stirring element. This is especially true when the arcuate in longitudinal section or polygonal extending side wall according to a preferred embodiment in the operation of the agitator follows a substantially concentric with the wavelength axis circular line.

The above-described embodiment of an agitator according to the invention or a stirrer equipped with such agitators allow energy and time to be saved during mixing and / or homogenization of a fluid medium and thus allow a particularly efficient stirring process to be carried out. In addition, differently shaped stirrers or Rührorgananordnungen be kept and replaced if necessary, so that the right stirrer is available for each application. The specific design and arrangement of the stirring elements, which are adapted to the material to be stirred and the container, also counteract the formation of dead zones, since the material to be stirred is completely captured and thoroughly mixed.

Fig.1

eine Ansicht einer Rührorgananordnung quer zur Wellenlängsachse eines Rührwerks,

Fig.2

einen Längsschnitt durch ein Rührorgan der Fig. 1 entlang der Schnittlinie B-B,

Fig.3

eine Ansicht der Rührorgananordnung nach Fig.1 parallel zur Wellenlängsachse,

Fig.4

Schnittansicht eines Rührorgans nach Fig.3 entlang der Schnittlinie A-A,

Fig.5

perspektivische Darstellung der Rührorgananordnung nach Fig.1,

Fig.6

eine weitere perspektivische Darstellung der Rührorgananordnung nach Fig.1.

A concrete embodiment of the present invention will be explained in more detail with reference to the drawings. Show it:

Fig.1

a view of a stirrer arrangement transverse to the longitudinal axis of a stirrer,

Fig.2

a longitudinal section through a stirrer of Fig. 1 along the section line BB,

Figure 3

a view of the stirrer assembly according to Fig.1 parallel to the wavelength axis,

Figure 4

Section view of an agitator after Figure 3 along the section line AA,

Figure 5

perspective view of the stirrer assembly according to Fig.1 .

Figure 6

a further perspective view of the stirrer assembly according to Fig.1 ,

Fig.1 is a Rührorgananordnung with two opposite to a common support arm 4 Rohrkörpem 1 can be seen. The support arm 4 consists of a flat steel which centrally carries a sleeve 7 for attachment of the stirring elements on a shaft of a stirrer. The attachment of the tubular body 1 formed as Rührorgane on the support arm 4 via a welded connection 4.1 (see Figure 3 ). Each stirring element comprises four side walls 1.1, 1.2, 1.3, 1.4, whose longitudinal edges are also welded together. The free side edges, that is, the end faces, form an inlet opening 2 and an outlet opening 3 for a medium flowing through. The respective opening cross-sections lie approximately in a plane which extends radially through the shaft center.

At least one side wall 1.3 of a tubular body 1 has an arcuate course in longitudinal section. It thus follows approximately one concentric to the longitudinal axis 5 circular line. The arcuately extending side wall opposite side wall 1.1 is compared with the longitudinal axis 6 of the support arm 4 at an angle γ = 45 ° employed. The formation and arrangement of the side walls 1.3 and 1.1 of the tubular body 1 cause the lying in the direction of rotation D and thus an inlet opening for a medium flowing through the opening 2 has a larger cross-section than the outlet opening 3. This is supported by the arrangement of the side walls 1.2 and 1.4, which converge toward the outlet opening 3 (see Fig.2 ).

Figure 3 It can be seen that the side wall 1.4 of the two tubular body 1 is not flat. The outlet opening 3, unlike the inlet opening 2 for the medium flowing through, has no rectangular cross section (see also FIG FIGS. 5 and 6 ).

The sectional view of Figure 4 shows the position of the support arm 4 and the sleeve 7 with respect to a stirrer 1. The sleeve 7 is arranged coaxially to the shaft longitudinal axis 5 and can be attached to attach the stirrers with the shaft on this. In the direction of rotation D acting locking elements cause a rotationally fixed connection of the stirring elements with the shaft. Like that Fig.4-6 can be seen, the support arm 4 is off-center with respect to the surface of the respective side wall 1.1 of the stirring elements 1. The sleeve 7 is arranged on a side surface of the support arm 4 such that it does not protrude beyond the stirring elements. This allows a compact design of the stirrer assembly.

Not shown, but still part of the agitator is an electric motor driven shaft, which is connectable to the Rührorganordnung. The shaft may be part of a tripod stirrer or other agitator that can be used in a container containing a fluid medium. Conveniently, the connection of the Rührorgananordnung with the shaft is detachable, so that the stirrer assembly can be exchanged and adapted to the particular application. Such an optimized stirrer allows complete mixing of the material in a very short time and with reduced drive power, so that the process can be described as particularly efficient.

Claims (12)

Agitator of an agitator for mixing and / or homogenizing fluid media with a tubular body (1) having an inlet opening and an outlet opening for a fluid medium, the inlet opening (2) being larger than the outlet opening (3),
characterized in that the tubular body (1) comprises four side walls (1.1, 1.2, 1.3, 1.4), of which at least one has an arcuate or polygonal course in longitudinal section. Stirring element according to claim 1,
characterized in that the tubular body (1) has a rectangular cross-sectional shape. Stirrer according to claim 1 or 2, characterized in that the arcuate or polygonal extending side wall (1.3) opposite side wall (1.1) is flat and has the shape of a trapezoid, wherein the two parallel side edges of the trapezoid each have a side edge of the inlet opening (2). and the outlet opening (3) form. Stirrer according to claim 3, characterized in that the side wall (1.1) opposite the arcuate or polygon-like side wall (1.3) has the shape of an isosceles trapezium and the two internal angles (a, β) at the long parallel side edge between 70 ° and 80 ° ; preferably 76 °. Stirrer according to one of claims 1 to 4, characterized in that the side walls (1.1,1.2,1.3,1.4) of the tubular body are welded together along their longitudinal edges (1.5). Agitator for mixing and / or homogenizing fluid media with a driven shaft and with at least two stirring members according to one of claims 1 to 5, wherein each stirring member via a support arm (4) in the direction of rotation D is fixedly connected to the shaft. Agitator according to claim 6, characterized in that each stirring member is connected via a hinged and / or pivotable support arm (4) with the shaft. Agitator according to claim 6 or 7, characterized in that the support arm (4) consists of a flat steel, which is fastened via a welded connection (4.1) to the stirring elements. Agitator according to one of claims 6 to 8, characterized in that in operation, the stirring elements are arranged rotationally symmetrical and at the same distance from each other. Agitator according to one of claims 6 to 9, characterized in that in operation at least one side wall (1.1) of each stirring element is aligned substantially parallel to the longitudinal axis (5) of the shaft. Agitator according to one of claims 6 to 10, characterized in that in operation the longitudinal axis (6) of the support arm (4) is oriented substantially perpendicular to the longitudinal axis (5) of the shaft and connected to the support arm (4) Side wall (1.1) relative to the longitudinal axis (6) of the support arm (4) has an angle of attack (γ) of 40 ° to 50 °, preferably 45 °. Agitator according to one of claims 6 to 11, characterized in that in operation, the arcuate or polygonal in the longitudinal section extending side wall (1.3) of a substantially to the shaft longitudinal axis (5) concentric circle follows.

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