ES2608557T3 - Mixing tool - Google Patents

Abstract

A mixing tool suitable for mixers with a mixing vessel, which can be fixed by means of a support arm (7) to a drive shaft that extends through the mixing vessel and can rotate the mixing tool in a direction of rotation (3), in which the mixing tool comprises the support arm (7) and a mixing member (4) disposed on the support arm (7), in which the member (4) of mixing has an opening (2) that passes through the mixing member (4) from an inlet side (13) to an outlet side (14) in the direction of rotation (3), in which the side (13) of inlet in the mixing member (4) has a cross section greater than the outlet side (14) in order to generate a convergent flow of the mixing material opposite the direction of rotation (3) with the member (4) of mixing during rotation, in which the opening (2) of the mixing member (4) is configured and n an arc shape or a circular arc shape in at least some regions, preferably on the side of the mixing member (4) facing away from the support arm (7), characterized in that the mixing member (4) it comprises an arc-shaped section (4c), at least one lateral rib (5) and a central rib (6), and by which the mixing member (4) comprises, on each of the two sides of the section ( 4c) with an arc shape, lateral ribs (5) that are connected through the central rib (6) fixed to the support arm (7).

Description

Mixing tool

The invention relates to a mixing tool according to the preamble of claim 1.

The mixing tool in question is suitable for mixing solids, solids-liquids or liquids. Mixing solids, such as bulk materials, results in particularly high requirements for the mixing tool. High mechanical strengths correspondingly cause high starting torques to start the mixing process, so that it results in high energy consumption in the mixer drive. Therefore, efficient operation of the mixer is not possible.

As a general rule, attempts are being made to obtain good mixing performance with suitable mixing tools and high torques on the drive shaft. For this purpose, it is necessary to design the mixer, the drive means and the mixing tool so that they are capable of coping with correspondingly high loads in order to meet the high mechanical requirements particularly when solids are mixed.

The mixing effect that can be achieved, the long operating time and, not least, the low wear, are essential criteria in the design of mixing tools of the type in question.

Mixing tools designed as plow grating blades are known, as described in DE 1 276 986. They comprise a mixing tool for mixers, for example, with a drum-shaped mixing vessel, in which the Mixing tool rotates with its edges separated a small distance from the wall of the mixing vessel. There are lifting ribs, which allow a high specific mixing effect, provided at the rear end of the mixing tool by means of cuts in the upper region of the side surfaces. However, the plow fence type mixing tool is not satisfactory in terms of energy efficiency,

Documents DE3901894A1, US1744294A, EP0530839A1, WO9005582A2, WO2009152382A2, DE 102010049034A1 and WO2010122092A2 also describe mixing tools.

Document DE 3901894 A1 describes a mixing tool according to the preamble of claim 1.

Furthermore, a shearing / mixing tool is known from DE 10 2009 01817 A1, which comprises a shear / thrust blade, an arm and a preferably triangular opening interposed therebetween. The opening serves for improved fluidization in the drying phase and, if necessary, a better and more complete mixing of the components during the mixing process. The shearing / mixing tool is primarily designed to achieve, in addition to a mixing effect, a restructuring of the material in the mixing material. For this purpose, the arm is straight, curved and / or inclined in order to promote the shearing action of the shearing / mixing tool.

The invention is based on the object of further improving and developing the known mixing tool, particularly with respect to energy efficiency during mixing.

The object is achieved with a mixing tool according to claim 1. The embodiments and advantageous developments are evident from the dependent claims.

What is essential is the idea of providing an opening in the mixing member that passes through it in the direction of rotation. The opening is configured so that a convergent flow of the mixing material opposite the direction of rotation can be generated with the mixing member. "Flow" means the amount of substance that passes through the opening of the mixing member, in which substances in a state of gas, liquid and / or solid aggregation can be used, in principle, as starting materials for the material of mixing.

The proposed solution is advantageous in that a considerably lower resistance is obtained, in particular when the mixing process is initiated, by means of the mixing member with the opening. Consequently, the starting torque is reduced. The weight reduction in the mixing tool, which is additionally achieved by means of the opening in the mixing member, and the moment of inertia altered in this way also have an effect on the general mixing operation. In this way, the energy consumption of the drive means during mixing can be reduced, so that the overall energy requirements are reduced, regardless of the level of filling of the mixing vessel. At the same time, it has been found that the mixing effect and the attainable mixing quality are maintained, so that a good specific mixing performance is made possible in an efficient manner. In this way, taking into account the entire operating time, a great energy saving can be achieved.

According to the invention, the opening of the mixing member is configured in an arc shape or a circular arc shape, at least in some regions, preferably on the side of the mixing member facing away from the support arm. In this way, together with the mixing vessel, in particular cylindrical, an optimum adaptation of the mixing member to the mixing vessel is possible. In this way, product depositions or caking of the mixing material on the walls of the mixing vessel can be prevented in an improved manner.

According to the invention, the mixing member comprises an arc-shaped section, at least one lateral nerve and a central nerve. In this way, a particularly robust configuration adapted to the loading of the mixing member can be obtained, particularly for the mixing of solids.

According to the invention, an inlet side in the mixing member has a larger cross section than an outlet side. Further improved, the opening of the mixing member is configured to narrow in a direction opposite to the direction of rotation. In that case, the mixing member is preferably equipped with inclined inner faces, for example, in the arc-shaped section, on the lateral nerve and / or the central nerve. The cross section of the inlet side, which is larger compared to the outlet side, allows a convergent flow of the mixing material over the mixing member. If a substance to be mixed is introduced into the opening of the mixing member, a convergent flow is generated by the rotation of the mixing tool in the direction of rotation. The convergent flow can be adjusted in a specific manner by means of the inclined inner faces in the mixing member. Subsequently, the substances of the mixing material, for example particles of a bulk material, are correspondingly reflected or deflected on the inner faces of the mixing member. At higher rotational speeds of the mixing tool in the mixing vessel, the reflection of the mixing material on the inner faces causes a reduced influence of the opening on the overall mixing effect, as if it were not present. In this way, the mixing effect can be adjusted in a specific way depending on the rotation of the mixing tool. It is advantageous, in particular, that the starting torque during start-up, as well as the energy consumption during the mixing procedure are reduced by the proposed mixing tool. Accordingly, the mixing member, the mixing tool and the drive means are subjected to lower torques and can be sized accordingly. With respect to the production process, the mixing tool can be manufactured with a smaller material thickness. Excess capacity and reactive current components can also be reduced in the case of drive means, such as electric motors.

In another embodiment, the distance between the inlet side and the outlet side of the mixing member is at least 20 mm, more preferably at least 40 mm. Said distance thus improves the transport characteristics for a convergent flow in the mixing member. With a correspondingly rapid rotation of the mixing tool, the specific mixing performance is improved at the same time.

In order to optimize the strength of the mixing tool, in particular of the mixing member, the mixing member can also be conveniently configured in a substantially blade-shaped manner, the opening in that case forming a cut inside the shovel shape

In a preferred embodiment, the height of the mixing member, seen from the front, is less than the width of the mixing member, preferably at least 30%, more preferably at least 50%. In this way, the resistance during the mixing process can be further optimized. Alternatively or additionally, the mixing member may also comprise on the inlet side a front edge that is preferably formed, seen in the direction of rotation, in the form of a blade edge, in particular to narrow to a point.

It is particularly advantageous to arrange the mixing member, seen from the side of the mixing tool, at an angle on the support arm. Preferably, the mixing member forms an angle of 10 ° to 50 °, more preferably 20 ° to 40 ° with respect to the axis of the support arm. The inclined arrangement of the mixing member on the support arm allows defined transport characteristics of the mixing material. Product deposition or caking of the mixing material on the walls of the mixing vessel in an improved manner with the arc-shaped section protruding from the mixing member can also be prevented.

Preferably, the opening of the mixing member is oriented substantially perpendicular to the plane of rotation of the mixing tool. The advantageous mixing characteristics of the mixing member can thus be performed in a particularly effective manner when mixed in the direction of rotation.

Preferably, the arrangement of the mixing tool in the mixing vessel is designed so that the mixing member ends at a short distance from the wall of the mixing vessel. Depending on the application, preferably several mixing tools are fixed to the drive shaft. Particularly preferably, the individual mixing tools are arranged in the drive shafts of

so that the individual mixing members of the mixing tools substantially sweep the entire interior surface of the mixing vessel during a 360 ° rotation of the drive shaft, so that no volume region of the mixing vessel is left out during the mixing procedure . As a result, a uniform homogeneous mixture can be obtained which, seen in the individual regions, has identical product properties.

The invention will be explained in more detail below with reference to the drawings that merely represent an exemplary embodiment. In the drawings

Fig. 1 shows a schematic front view of a mixing tool,

Fig. 2 shows a perspective view of the mixing tool, and

Fig. 3 shows a rear view of the mixing tool.

It should be noted that the proposed mixing tool can be applied in all imaginable areas, such as the chemical, pharmaceutical, food and construction materials industry. In a preferred embodiment, the proposed mixing tool is used to mix solids, for example in the treatment of bulk materials in which liquids can also be added in order to humidify the mixing material.

Particularly preferably, the mixing tool is used together with a horizontally or vertically oriented cylindrical mixing vessel, in which a drive shaft is correspondingly arranged in a concentric manner. Then, the size, number and arrangement of the proposed mixing tools on the drive shaft can be conveniently adapted to the respective application in order to achieve a desired mixing effect. Apart from a rotation of the one or more mixing tools in the mixing vessel, it is also possible to configure the mixing vessel itself so that it is rotatable.

The mixing tool 1 in question is equipped, as shown in Figures 1 to 3, with a support arm 7 for connection to the drive shaft, as well as with a mixing member 4. As is evident from Fig. 1, the mixing member 4, seen from the front, has an opening 2, which is configured in a circular arc shape. Accordingly, the mixing member 4 comprises an arc-shaped section 4c. In that case, the mixing tool 1 can be arranged for example in a cylindrical mixing vessel so that the distance between the mixing member 4 and the wall of the mixing vessel is as small as possible, in order to prevent in this way the product depositions or the caking of the mixing material on the wall.

The essential thing now is that the mixing member 4 with the opening 2 achieves a lower resistance in the mixing material, so that, in particular, the starting torque of the mixing tool 1 during startup is reduced. Smaller torques are also obtained during the mixing process itself, so that energy consumption in the drive means is reduced. In this way, global energy requirements can be reduced.

The mixing member 4 comprises, on each of the two sides of the arc-shaped section 4c, lateral ribs 5c which are connected by a central rib 6 fixed to the support arm 7. In that case, the support arm 7 is therefore connected to the drive shaft of the mixer. The support arm 7 can be attached to the drive shaft in a removable manner, or the support arm 7 can be welded to the drive shaft. The inner faces 8 of the mixing member are preferably configured as inclined inner faces. For this purpose, the lateral nerve, for example, has an inclination 9a, seen in the circumferential direction 3. With this, the opening 2 of the mixing member 4 can be specifically adjusted to obtain a convergent flow of the mixing material. The details related to the inner faces 8 and the configuration of the opening 2 are explained later in the present specification.

In this case, the height of the mixing member 11 is configured to be smaller than the width of the mixing member 12. Preferably, the height of the mixing member 11 is less than the width of the mixing member by at least 30%, more preferably at least 50%. With this height-to-width ratio of the mixing member 11, advantages can be obtained as regards the flow.

From the illustration in Fig. 2, it is evident that the mixing member 4 is in this case configured in a substantially blade-shaped manner, with the opening 2 forming a cutout inside the blade shape. The direction of arrow 3 indicates the direction of rotation of the mixing tool 1 in the mixing vessel. In this way, the result is an input side 13 in the mixing member 4, which serves for the input of the mixing material into the opening 2, and an output side 14, from which the introduced part of the mixing material exits from the opening 2. The inlet side 13 of the mixing member 4 has a larger cross section than the outlet side 14. Accordingly, the opening 2 of the mixing member 4 is configured so that the opening 2 is 4 10

narrow in a direction opposite to direction 3 of rotation. In that case, the inner faces 8 of the mixing member 4 are inclined accordingly. The inclination of the central rib 9b or the arc-shaped section 9c in this case preferably refers to a straight line perpendicular to the plane of the opening 2. Preferably, the central rib 9b, the arc-shaped section 9c and / or the 9th lateral nerve are inclined at an angle of 30º to 60º. This ensures that the particles of the substance of the mixing material are reflected or deflected specifically on the inner faces of the mixing member 4. At higher rotation speeds of the mixing tool, the influence of the opening 2 on the mixing effect is thus reduced in an improved manner. Because the higher torque is particularly required when the mixing procedure is started, due to the high starting torque, the proposed mixing tool allows an energy efficient start of the mixing procedure. As the speed of rotation of the mixing member 1 increases, a good specific mixing becomes possible due to the specific convergent flow in the mixing member, because the influence of the opening 2 on the mixing effect decreases as a function of rotation speed

Conveniently, the mixing member 1 may also have a front edge 4a on the inlet side 13 that may be formed in the form of a shovel edge, in particular to reduce resistance. The opening 2 of the mixing member is preferably oriented perpendicular to the plane of rotation of the mixing tool 1. This is important for the mixing characteristics of the mixing member.

As is evident from Figs. 2 and 3, the mixing member 4, seen from the side, is preferably provided at an angle on the support arm 7. Particularly advantageously, the mixing member forms an angle of 10 ° to 50 °, more preferably 20 ° to 40 °, with respect to axis 10 of the support arm. With this arrangement of the mixing member 4, advantages can be obtained with respect to the transport characteristics of the mixing tool 1.

It is also especially advantageous to arrange the mixing member 4 at an angle of inclination with respect to the wall of the mixing vessel. Accordingly, the arc-shaped section 4c of the mixing member 4 then forms a recess, in particular wedge-shaped, with the wall of the mixing vessel. In that case, the separation of the arc-shaped section 4c with respect to the wall of the mixing vessel is preferably smaller in the front area, that is, in the inlet side 13, than in the rear region, that is, on the outlet side 14 of the mixing member. In this way, the angle of inclination between the mixing member 4 and the wall of the mixing vessel can be specifically adjusted. Because the angle of inclination opens in a direction opposite to the direction of rotation 3, compactions of the mixing material between the wall of the mixing vessel and the mixing member can be avoided. This also makes it possible to keep the power consumption of the drive shaft low. Depending on the specific product properties of the mixing material, the angle of inclination and the distance of the mixing member 4 from the wall of the mixing vessel can be specifically optimized.

The mixing tool 1 is illustrated in a rear view in Fig. 3. The rear part of the mixing member 4b is preferably flat. From the illustration in Fig. 3, it is evident that the arc-shaped section 4c is preferably configured as a bent plate, in particular with a thickness of at least 5 mm. Accordingly, the arc-shaped section 4c, as a whole, may be configured as an inclined plate, viewed in the direction of rotation. This allows an inclination of the inner face 8 on the arc-shaped section 4c and, at the same time, towards the outside, a suitable angle of inclination of the mixing member 4 on the wall in the mixing vessel.

The mixing tool 1 preferably consists of steel, particularly preferably, stainless steel, in order to obtain a wear-adapted configuration.

In a preferred embodiment, several proposed mixing tools 1 are arranged on a drive shaft. In particular, the mixing tools 1 are arranged on the drive shaft so that the individual mixing members of the mixing tool substantially sweep the entire inner surface of the mixing vessel during a 360 ° rotation of the drive shaft. This ensures that no volume region of the mixing vessel is left out during the mixing procedure.

In the tests with the proposed mixing tools, it has been found that the starting torque when starting the mixer is reduced compared to conventional mixing tools already in the case of unfilled mixing containers. In the tests with different levels of filling (in this case using quartz sand) and different speeds of rotation of the mixing tool, it was found that, in the proposed mixing tool, not only the starting torque is lower when starting the mixing procedure, but the average torque is also reduced as a whole. At the same time, the quality of mixing in the different samples produced with the proposed mixing tools and conventional mixing tools did not show significant differences with respect to the extinction determined by means of an extinction measurement using a photometer (λ = 690 nm ). Depending on the level of filling, energy savings of up to 20% could be found compared to conventional mixing tools.

Reference Numbers 10

one

Mixing tool

2

Opening

3

Rotation direction

4

Mixed member

4th

Front edge of the mixing member

4b

Rear of the mixing member

4c

Arc-shaped section

5

Lateral nerve

6

Central nerve

7

Support arm

8

Inner face of the mixing member

9a

Tilt of the lateral nerve

9b

Central nerve tilt

9c

Inclination of the arc section

10

Support arm shaft

eleven

Mixing member height

12

Mixing member width

13

Inlet side on mixing member

14

Outlet side in the mixing member

Claims (6)

1. A mixing tool suitable for mixers with a mixing vessel, which can be fixed by means of a support arm (7) to a drive shaft that extends through the mixing vessel and can rotate the mixing tool. mixing in a rotation direction (3), in which the mixing tool comprises the support arm (7) and a mixing member (4) disposed on the support arm (7), in which the member (4 The mixing has an opening (2) that passes through the mixing member (4) from an inlet side (13) to an outlet side (14) in the direction of rotation (3), in which the side (13) inlet in the mixing member (4) has a cross section greater than the outlet side (14) in order to generate a convergent flow of the mixing material opposite the direction (3) of rotation with the member (4) mixing during rotation, in which the opening (2) of the mixing member (4) is configured in an arc shape or a circular arc shape in at least some regions, preferably on the side of the member ( 4) mixing oriented in the opposite direction to the support arm (7), characterized in that the mixing member (4) comprises an arc-shaped section (4c), at least one lateral rib (5) and one rib (6) ) central, and by which the mixing member (4) comprises, on each of the two sides of the arc-shaped section (4c), lateral ribs (5) that are connected through the fixed central nerve (6) to the support arm (7).

2.

Mixing tool according to the preceding claim, characterized in that the opening (2) of the mixing member (4) narrows in a direction opposite to the direction of rotation (3), preferably with inner faces (8) inclined in the member ( 4) mixing.

3.

Mixing tool according to any one of the preceding claims, characterized in that the distance between the inlet side (13) and the outlet side (14) of the mixing member (4) is at least 20 mm, more preferably at least 40 mm

Four.

Mixing tool according to any one of the preceding claims, characterized in that the mixing member (4) is configured in a substantially blade-shaped manner, with the opening (2) forming a cutout inside the blade shape.

5.

Mixing tool according to any one of the preceding claims, characterized in that the mixing member (4) comprises on the inlet side (13) a front edge (4a) that is preferably formed, seen in the direction (3) of rotation , in the form of a blade edge, in particular, so that it narrows to a point.

6.

Mixing tool according to any one of the preceding claims, characterized in that the opening (2) of the mixing member (4) is oriented substantially perpendicular to the plane of rotation of the mixing tool (1).