Mixing device

Abstract

The invention relates to a mixing device (10) for mixing a building material, comprising a conveying pipe (18), a metering screw arranged in the conveying pipe (18) and driven by a first drive (20), a buffer tank (12) connected to the conveying pipe (18), and a mixing unit (28) having an elongated mixing tube (24) whose inlet is connected to an outlet of the conveying pipe (18). At least one elongated mixing element, in particular extending longitudinally along the mixing tube (24), is arranged in the mixing tube (24) and is driven by a second drive (26). The mixing tube (24) has a water inlet (28), and the first and second drives (20, 26) can be controlled independently of each other. In this way, the mixing activity of the mixing device is decoupled from its conveying activity, which considerably expands the possible mixing parameters.

Description

[0001] The present invention relates to a mixing device for mixing a building material. Such a mixing device, which is used in particular for mixing a dry building material homogenized in a mixing drum with water, generally has a buffer tank connected to a mixing tube in which the building material is conveyed and mixed with water. This device, known, for example, from EP 2 239 120 A2, provides good mixing results but has the disadvantage that the mixing parameters are limited.

[0002] It is therefore an object of the invention to provide a mixing device that allows for the greatest possible variability of the mixing parameters. This object is achieved by a mixing device with the features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims. Advantageous embodiments of the invention are also described in the description and in the drawing.

[0003] While in the prior art the conveying and mixing of the building material with water took place in a mixing tube, in the invention the conveying and mixing of the building material with water are assigned to two separate areas. Conveying is carried out by means of a conveying tube in which a metering screw driven by a first drive is arranged, and which conveying tube is connected to a buffer tank. Furthermore, the mixing device includes a mixing unit separate from the conveying tube, which has an elongated mixing tube whose inlet is connected to an outlet of the conveying tube. At least one longitudinally extending mixing element, preferably designed as a mixing screw, is arranged in the mixing tube. This mixing element is driven by a second drive.The mixing tube has a water inlet, allowing the building material to be mixed with water within it. The discharge end of the mixing tube, from which the finished mixture can be dispensed, is preferably located at the end furthest from the inlet, so that the entire length of the mixing tube can be used for mixing. Because the first and second drives can be controlled independently, the conveying speed and mixing activity can be controlled separately, significantly expanding the mixing parameters. This allows, for example, the adaptation of building materials requiring different mixing intensities. In this way, a highly customized addition of water to the dry building material can be achieved.

[0004] If necessary, further additives, such as chemical sealants for waterproof concrete, etc., can be added via an advantageously formed feed opening for additives in the mixing tube and mixed with the dry building material in order to achieve a desired individual property of the concrete produced from the mixture.

[0005] In an advantageous embodiment of the invention, the conveying pipe is inclined upwards at an angle of 10 to 75°, and in particular at an angle of 20 to 60°, to its outlet relative to the horizontal. This inclined arrangement ensures, firstly, that the conveying pipe is always well filled, which is advantageous for precise metering of the building material to the mixing pipe, and secondly, that the inclined arrangement saves space in the horizontal direction, allowing for a more compact arrangement of the mixing device in the horizontal plane.

[0006] The outlet of the conveying pipe is preferably located near its end, so that the entire length of the pipe can be used for metering the building material. Furthermore, if the outlet is located near its upper end, the conveying pipe is always 100% full, enabling precise metering.

[0007] In an advantageous embodiment of the invention, the inlet of the mixing tube is connected to the outlet of the conveying tube via a substantially vertical downpipe. The mixing tube is generally arranged horizontally, so that a vertical downpipe between the inclined conveying tube and the horizontal mixing tube saves space in the horizontal plane and also provides a reliable connection between the conveying tube and the mixing tube, which is resistant to clogging or the accumulation of components. However, it is also possible, in principle, to connect the inlet of the mixing tube directly to the outlet of the conveying tube.

[0008] As already explained above, the at least one mixing element is preferably arranged as a mixing screw. Two mixing screws can also be arranged side by side in the mixing tube, preferably moving in opposite directions. The arrangement and design of mixing elements are known from the prior art, and a wide variety of mixing elements can be used from this.

[0009] Preferably, the buffer tank is designed as a vertically extending container, connected along its underside to the conveying pipe and open towards it. This ensures that the buffer tank, which is usually well-filled, empties completely into the conveying pipe, thus keeping the conveying pipe consistently filled with building material. The buffer tank is typically connected to a central outlet opening of a mixing drum, for example, of a concrete mixer truck or a mixing container, and receives the building material through this central opening. Therefore, the buffer tank preferably has an opening in a vertical end wall for connection to such a mixing drum or other storage container for building materials. This type of buffer tank application is known per se and has proven to be very reliable.The vertical extension of the buffer tank also saves space in the horizontal plane, which is important for its arrangement on, for example, a mixing vehicle due to the limited space available.

[0010] Preferably, the first drive for the metering screw is arranged at an end face of the conveying tube. It is easily accessible from this end face and therefore easy to maintain, and it does not obstruct any inlets or outlets located in the casing of the conveying tube. The drive could also be powered by a motor via a chain at the end face of the metering screw. The motor / drive itself does not necessarily have to be located at the end face. An important aspect is that the force from the drive is applied to the metering screw shaft at the end face.

[0011] Similarly, the second drive for the at least one mixing element of the mixing tube is preferably arranged at an end face of the mixing tube. It is easily accessible from this end face and therefore easy to maintain, and it does not obstruct inlets located in the casing of the mixing tube, e.g., for water and / or additives. It should be noted that the mixing tube generally has a circular cylindrical base. However, it can also have other base shapes, such as square, rectangular, oval, or ellipsoidal, depending on the design of the mixing elements of the at least one mixing element located in the mixing tube. The motor / drive itself therefore does not necessarily have to be located on the end face of the mixing tube. The essential aspect is that the force from the drive is applied to the shaft of the at least one mixing element at the end face.

[0012] Preferably, the mixing tube is arranged transversely to the conveying pipe and extends horizontally. Mixing the construction material with water is best achieved in a horizontally extending mixing tube, as this allows the water to spread most effectively along its length. Preferably, the mixing tube is pivotably arranged in the horizontal plane relative to the conveying pipe, enabling it to pivot between an operating position, which typically extends longitudinally along the mixing vehicle or container, and a rest position transverse to it. In this way, it does not interfere with the transport vehicle's movement when in the rest position. In its operating position, the rear discharge end of the mixing tube can extend further beyond the rear of the transport vehicle or container, thus providing easier access for filling concrete silos handled by a crane.

[0013] The invention also relates to a concrete mixer truck comprising a wheeled frame on which a rotatable mixing drum for dry building materials is arranged, the drum having a central opening connected to an end-face opening of the buffer tank of a mixing device of the type described above. Similarly, the invention also relates to a concrete mixing container having a rotatable mixing drum connected to the central opening of the buffer tank of a mixing device of the type described above.

[0014] Finally, the invention also relates to a storage container for dry building materials, which is connected, in particular via a conveying device, to the opening of the buffer container of a mixing device of the type described above. Regarding the features and advantages of the invention, reference is made to the above description of the mixing device.

[0015] The invention is described below by way of example with reference to a schematic example in the drawing. This drawing shows: Fig. 1 a side view of an embodiment of a mixing device according to the invention, Fig. 2 a front view of the mixing device according to Fig. 1 , Fig. 3 a top view of the mixing device according to Fig. 1 , Fig. 4 a concrete mixer truck with a mixing device according to Fig. 1 , and Fig. 5 a side view of a concrete mixing container with a mixing device according to Fig. 1 .

[0016] The mixing device 10 according to the invention is described below with reference to the Figs. 1 to 3 described. The mixing device 10 includes a vertically extending buffer tank 12, which is connected at its end face 14 to a mixing drum 40 of a concrete mixer truck 32 or a concrete mixing container 42 ( Fig. 4 and 5) is connectable. A conveying pipe 18 is arranged on an inclined lower edge 16 of the buffer tank 12, which is inclined at an angle of approximately 45°, and is connected to the buffer tank 12 via an inlet. A screw conveyor (not shown) runs inside the conveying pipe 18 and is driven by a first drive 20 located at the lower end face of the conveying pipe 18. In the region of its upper end, the conveying pipe 18 is connected to a vertically downward-projecting downpipe 22, which is connected at its lower end to a mixing unit 23. This mixing unit comprises a mixing pipe 24 with at least one mixing element (not shown), e.g., a mixing screw, arranged in the mixing pipe and driven by a second drive 26. A water inlet 28 or an inlet for additives is also arranged on the mixing pipe 24.At its end facing away from the second drive 26 there is a downward-projecting outlet 30 of the mixing tube, from which concrete silos handled by a crane can easily be filled.

[0017] The advantage of those in the Figs. 1 to 3 The mixing device shown consists in the fact that the feed of the building material and the mixing activity of the mixing screw in the mixing tube 24 can be controlled separately via the two drives 20, 26, so that the building material can be mixed individually with water as well as with additional additives, independently of the material feed rate. A separate inlet can be provided in the mixing tube 24 for the addition of additives, or the water inlet can be used.

[0018] Fig. 4Figure 32 shows a concrete mixer truck, which has a frame 34 with wheels 36. A vehicle cab 38 is also mounted on the frame 34, from which a rotatable mixing drum 40 and a mixing device 10 flanged to the rear are mounted, as shown in the figures. Figs. 1 to 3 can be controlled.

[0019] Similarly, it shows Fig. 5 a concrete mixing container 42, which also has a frame 44 on which a rotatable mixing drum 40 with a flanged mixing device 10 is located. The mixing device 10 can thus be flanged to stationary as well as mobile mixing drums or other storage containers for dry building materials.

[0020] The invention is not limited to the illustrated embodiment, but can instead be varied within the scope of protection of the attached patent claims. Reference symbol list:

[0021] 10 Mixing device 12 Buffer tank 14 End of buffer tank for connection to a mixing drum or a building material container 16 Lower edge of buffer tank for connection to the conveying pipe 18 Conveying pipe 20 First drive on the end of the conveying pipe for driving the conveying or metering screw 22 Vertical downpipe for connecting the outlet of the conveying pipe to the inlet of the mixing pipe 23 Mixing unit 24 Mixing pipe 26 Second drive for at least one mixing element of the mixing pipe, e.g. for a mixing screw 28 Water inlet or inlet for additives 30 Outlet end of the mixing pipe 32 Concrete mixer truck 34 Frame of the concrete mixer truck 36 Wheels of the concrete mixer truck 38 Cab of the concrete mixer truck 40 Mixing drum 42 Concrete mixing container 44 Frame of the concrete mixing container

Claims

1. Mixing device (10) for mixing a building material, comprising a conveying pipe (18), a metering screw arranged in the conveying pipe (18) and driven by a first drive (20), a buffer tank (12) connected to the conveying pipe (18) and a mixing unit (23) comprising an elongated mixing tube (24) whose inlet is connected to an outlet of the conveying pipe (18), wherein - at least one mixing element, in particular extending in its longitudinal direction, is arranged in the mixing tube (24), - the at least one mixing element is driven by a second drive (26), - the mixing tube (24) has a water inlet (28), - the first and second drives (20, 26) are controllable independently of each other.

2. Mixing device (10) according to claim 1, characterized by the fact that an outlet (30) of the mixing tube (24) is arranged in the region of its longitudinal end.

3. Mixing device (10) according to claim 1 or 2, characterized by the fact thatthe conveying pipe (18) is inclined upwards towards its outlet at an angle of 10 to 75 degrees relative to the horizontal, in particular at an angle between 20 degrees and 60 degrees.

4. Mixing device (10) according to one of the preceding claims, characterized by the fact that the outlet of the conveying pipe (18) is arranged in the area of ​​its end, preferably in the area of ​​its upper end.

5. Mixing device (10) according to one of the preceding claims, characterized by the fact that the inlet of the mixing tube (24) is connected to the outlet of the conveying tube (18) via a substantially vertically running downpipe (22).

6. Mixing device (10) according to one of the preceding claims, characterized by the fact that that at least one mixing element is designed as a mixing screw.

7. Mixing device (10) according to one of the preceding claims, characterized by the fact thatthe buffer tank (12) is designed as a vertically extending container which is connected to the conveying pipe (18) over a length at its underside and is open towards it.

8. Mixing device (10) according to claim 7, characterized by the fact that the buffer tank (12) has an opening in a vertical end wall (14) for connection to a mixing drum or other storage container for building materials.

9. Mixing device (10) according to one of the preceding claims, characterized by the fact that the first drive (20) is arranged at a front end of the conveying tube (18).

10. Mixing device (10) according to one of the preceding claims, characterized by the fact that the second drive (26) is arranged at a front end of the mixing tube (24).

11. Mixing device (10) according to one of the preceding claims, characterized by the fact that the mixing tube (24) preferably extends transversely to the conveying tube (18), in particular horizontally.

12. Mixing device (10) according to one of the preceding claims, characterized by the fact that the mixing tube (24) has an inlet (28) for the addition of additives.

13. Concrete mixer vehicle (32) comprising a frame (34) provided with wheels (36) on which a rotatable mixing drum (40) for dry building materials is arranged, which has a central opening which is connected to an end-face opening (14) of the buffer container (12) of a mixing device (10) according to one of the preceding claims.

14. Concrete mixing container (42) on which a rotatable mixing drum (40) for dry building materials is arranged, which has a central opening that is connected to an end-face opening (14) of the buffer container (12) of a mixing device (10) according to one of the preceding claims.

15. Storage container for storing dry building materials, which is connected, in particular via a conveying device, to the opening (14) of the buffer container (12) of a mixing device (10) according to one of the preceding claims.

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