CEMENT PREMIXER, A DEVICE FOR PRODUCING A CONCRETE MIXTURE AND A METHOD FOR PRODUCING A CEMENT SUSPENSION

Abstract

A cement premixer includes a treatment container having a treatment space. The treatment container has a side wall and a bottom, and at least one stirring unit at least partially projecting into the treatment space. The stirring unit is connected to a shaft having an axis of rotation. At least one ultrasonic probe projects at least partially into the treatment space. At least one ultrasonic oscillator applies ultrasound to the at least one ultrasonic probe. The cement premixer has at least one first introduction opening for the supply of cement and an outlet for the flow supply line for feeding a cement suspension provided by the cement premixer into a concrete-mixing device.

Claims

1-22. (canceled)

23. A cement premixer, comprising a treatment container having a treatment space, wherein the treatment container comprises a side wall and a bottom; a stirring unit at least partially projecting into the treatment space, wherein the stirring unit is connected to a shaft having an axis of rotation; at least one ultrasound probe at least partially projecting into the treatment space; at least one ultrasonic oscillator configured to emit ultrasound to the at least one ultrasonic probe; a control and/or evaluation unit configured to adjust the emitted ultrasound with an intensity of 25-250 W/cm.sup.2 and an amplitude of 15-500 μm; at least a first introduction opening configured to supply cement; and an outlet for a flow supply line to supply a cement suspension from the cement premixer into a concrete mixer.

24. The cement premixer of claim 23, wherein the cement premixer has a flange configured for connection to the concrete mixer.

25. The cement premixer of claim 23, wherein the at least one ultrasonic probe at least partially projects into the treatment space through the side wall of the treatment container.

26. The cement premixer of claim 23, wherein the treatment container has an axially symmetrical and rotationally symmetrical side wall, wherein an axis of symmetry of the side wall extends parallel to the axis of rotation of the stirring unit.

27. The cement premixer of claim 26, wherein the side wall has an extension in a half towards the bottom, wherein the extension extends around an entire circumference of the side wall concentrically to the axis of symmetry.

28. The cement premixer of claim 27, wherein the at least one ultrasonic probe comprises three or more ultrasonic probes projecting into the treatment space distributed at a same angle to one another about the axis of symmetry of the side wall.

29. The cement premixer of claim 28, wherein the three or more ultrasonic probes are arranged in a region of the extension in the side wall.

30. The cement premixer of claim 26, wherein the at least one ultrasonic probe has a longitudinal axis and the longitudinal axis is arranged at an angle of 55° to 65° to the axis of symmetry of the side wall of the treatment container and is aligned in a direction of the bottom of the treatment container.

31. The cement premixer of claim 23, wherein the cement premixer has a control and/or evaluation unit configured to control the stirring unit in such a way that operation takes place at speeds of 200 revolutions per minute to 300 revolutions per minute.

32. The cement premixer of claim 23, further comprising: a level sensor configured to determine a filling level of the cement premixer.

33. The cement premixer of claim 32, wherein the control and/or evaluation unit is configured to control an agitation speed of the stirring unit or an energy input of the ultrasonic oscillator as a function of the determined filling level.

34. A device for producing a concrete mix, the device comprising: a concrete mixer; and a cement premixer, which the cement premixer comprises a treatment container having a treatment space, wherein the treatment container comprises a side wall and a bottom; a stirring unit at least partially projecting into the treatment space, wherein the stirring unit is connected to a shaft having an axis of rotation; at least one ultrasound probe at least partially projecting into the treatment space; at least one ultrasonic oscillator configured to emit ultrasound to the at least one ultrasonic probe; a control and/or evaluation unit configured to adjust the emitted ultrasound with an intensity of 25-250 W/cm.sup.2 and an amplitude of 15-500 μm; at least a first introduction opening configured to supply cement; and an outlet for a flow supply line to supply a cement suspension from the cement premixer into the concrete mixer.

35. The device of claim 34, wherein the cement premixer is fluidically connected to the concrete mixer by a flanged connection between the outlet of the cement premixer and an inlet of the concrete mixer.

36. The device of claim 35, further comprising at least one of the following: a first cement container; a second cement container; a water inlet; and an admixture container, wherein the inlet of the concrete mixer is an inlet pipe or inlet shaft, wherein the inlet pipe or inlet shaft is detachably connected by a flange connection to at least the first cement container, the water inlet, or the admixture container.

37. The device of claim 34, further comprising: a metering device arranged between the cement premixer and the concrete mixer, wherein the metering device is configured to regulate metering of the cement suspension as a function of an amount of sand, gravel, or grit supplied.

38. A method, comprising: supplying cement and water into a treatment container having a treatment space; mixing, by at least one stirring unit at least partially projecting into the treatment space, the supplied cement and water to produce a cement suspension; transmitting, by at least one ultrasonic probe at least partially projecting into the treatment space, ultrasonic oscillations; and discharging the cement suspension via an outlet for further processing in a concrete mixer.

39. The method of claim 38, wherein the discharging of the cement suspension is performed according to a specific energy input per unit volume of the cement suspension.

40. The method of claim 38, wherein, based on a total mass of the cement suspension, with all components in the cement suspension adding up to 100 parts by weight, the cement suspension is from 20 parts by weight to 80 parts by weight cement; from 20 parts by weight to 80 parts by weight water; and from 0 to 10 parts by weight admixture.

41. The method of claim 38, wherein ultrasonic oscillations are generated by at least one ultrasonic oscillator, which applies ultrasound to the at least one ultrasonic probe.

42. The method of claim 38, wherein the stirring unit is operated at a speed of 200-300 revolutions per minute.

43. The method of claim 42, wherein the at least one ultrasonic probe transmits ultrasound in a frequency range from 18 kHz to 22 kHz into the cement suspension.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0086] An exemplary embodiment of the invention is now described in more detail below with reference to the accompanying drawing.

[0087] Herein, FIG. 1 shows a schematic cross-sectional view of an exemplary embodiment of the cement premixer according to the present invention;

[0088] FIG. 2 shows a top view of the exemplary embodiment of FIG. 1;

[0089] FIG. 3 shows a schematic diagram of concrete production by conventional methods; and

[0090] FIG. 4 shows a schematic diagram of a concrete production according to one embodiment of the present invention.

DETAILED DESCRIPTION

[0091] The following stipulation applies to the entire further description: If reference numerals are included in a figure for the purpose of graphic clarity, but are not explained in the directly associated descriptive text, reference is made to their mention in preceding figure descriptions.

[0092] As can be seen in FIG. 1, the cement premixer 1 comprises a treatment container 2, which has a treatment space 20. The treatment space 20 is delimited laterally by a rotationally symmetrical side wall 21 and downwardly by a bottom 22. Upwardly, the treatment space is closed by a lid 24. A stirring unit 3 with a shaft 30 projects into the treatment space 20, wherein the shaft projects into the treatment space through an opening in the lid 24.

[0093] In this embodiment, the side wall 21 has an outward extension 25 in the lower half. Four ultrasonic probes 4 are mounted in this area.

[0094] In this embodiment, the stirring unit 3 has two agitators (3.1, 3.2) that are attached to the shaft 30. The agitator blades of the agitators (3.1, 3.2) are spaced so that they do not touch the ultrasonic probes 4. The shaft 30 is set into rotary motion via the rotary disk by an external drive 5.

[0095] The shaft has an axis of rotation 31 coinciding with the axis of symmetry 23 of the side wall 21. The extension 25 is arranged concentrically to the axis of symmetry 23 outward (away from the axis of symmetry 23).

[0096] Laterally, at an angle of 60° to the vertical axis of symmetry 23 of the side wall 21, are the ultrasonic probes 4, which are directed downward toward the bottom 22.

[0097] In this embodiment, a control and/or evaluation unit 9 records the parameters filling level, energy input by the ultrasonic probes, and added water quantity by the water quantity meter 64. It controls the drive 5 for the stirring unit 3 (setting the number of revolutions of the stirring unit 3), the ultrasonic oscillators 42 in amplitude and frequency of the ultrasound (in this case, the energy input is determined by the control and/or evaluation unit 9), the solids valve 61, the water control valve, and the discharge of the suspension via the metering valve 71.

[0098] Furthermore, there is an introduction opening 60 in the lid 24, into which a pipe 6 for the supply of solids projects. This is controlled via the solids valve 61. In this embodiment, cement is added and the addition of cement is controlled via the solids valve 61. A water introduction line 62 for water is arranged through the side wall 21. Thus, water can be added via the water control valve 63 to produce the cement suspension. In this embodiment, the amount of water that is added is determined by the water quantity meter 64.

[0099] The level sensor 8 determines the level within the treatment space 20. This level measurement can, for example, be used by the control and/or evaluation unit as a basis for controlling the addition of water.

[0100] In the bottom 22 of the treatment container 2 there is an outlet 70 for the flow supply line 7 for discharging the finished cement suspension to the concrete mixer. The discharge of the cement suspension is controlled as a function of the specific energy input per unit volume via the metering device 71. The discharge line 7 is provided with a flange 72, with which the discharge line 7 can be quickly and easily connected to a concrete mixer.

[0101] FIG. 2 shows a top view of the embodiment of FIG. 1, wherein the arrangement of the four ultrasound probes 4 with an angle of 90° to each other in the side wall 21 is particularly visible here. The view into the treatment space 20 shows that the ultrasonic probes 4 are directed towards the axis of symmetry 23 of the side wall 21.

[0102] A flange can be coupled to the drive by means of mounting holes to allow the drive of the shaft 30 and thus the stirring unit 3.1 and 3.2.

[0103] FIG. 3 schematically shows the process according to the conventional method. In a concrete mixer 100, water is poured from the water inlet 200, admixtures from the admixture container 300, cement from the first or second cement container 400 and 500 and aggregate (sand, gravel and/or grit) from the corresponding containers 600, 700 and 800. The components are mixed directly in the concrete mixer to obtain a concrete mix.

[0104] In contrast to this conventional mode of operation, in the method according to the invention, which is shown schematically according to an embodiment in FIG. 4, a cement suspension is generated separately in the cement premixer 1. In this process, water from the water inlet 200 and cement from the cement containers 400 and/or 500 and, optionally, admixtures from the admixture container 300 are processed in the cement premixer to form a cement suspension. This cement suspension is then transferred from the cement premixer 1 to the concrete mixer 100. In the concrete mixer, the aggregate from the corresponding containers 600, 700 and 800 is then added to produce the concrete mix, which can then be further processed.

[0105] The combination of the cement premixer 1 and the concrete mixer 100 forms the device 1000 for producing a concrete mix.

[0106] The preparation of the activated cement suspension can be operated either in a batch process or in a continuous process.

Example

[0107] A concrete was produced by the method according to the invention for producing a cement suspension.

[0108] A laboratory-scale cement premixer according to the invention, as shown in FIG. 1, with a diameter of 400 mm up to 493 mm at the widest point and a total height of 550 mm, is distributed with 4 ultrasonic probes (sonotrodes) at 90° to each other around the axis of symmetry of the treatment container.

[0109] The treatment space contains 45 kg of cement, 20 liters of water and 0.5 kg of superplasticizer (admixture).

[0110] The stirring unit is operated at a speed of 250 revolutions per minute. Oscillations are transmitted in the low ultrasonic range of 20 kHz via the sonotrodes into the treatment space.

[0111] By using the ultrasonic treatment and the mixing tool, a fast and efficient homogenization of the cement suspension is achieved within less than 180 seconds.

[0112] The cement suspension produced in this way is transferred to a concrete mixer. Here, 225 kg of aggregate are added and the concrete is mixed.

[0113] The flowability of this concrete is significantly increased compared to conventional production methods and the early strength is considerably improved. Especially in the production of precast concrete parts, this leads to decisive advantages and precast parts of better quality, which can be produced in a shorter time.

[0114] Although the invention has been illustrated and described in detail by way of preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived from these by the person skilled in the art without leaving the scope of the invention. It is therefore clear that there is a plurality of possible variations. It is also clear that embodiments stated by way of example are only really examples that are not to be seen as limiting the scope, application possibilities or configuration of the invention in any way. In fact, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete manner, wherein, with the knowledge of the disclosed inventive concept, the person skilled in the art is able to undertake various changes, for example, with regard to the functioning or arrangement of individual elements stated in an exemplary embodiment without leaving the scope of the invention, which is defined by the claims and their legal equivalents, such as further explanations in the description.

LIST OF REFERENCE SIGNS

[0115] 1 Cement premixer [0116] 2 Treatment container [0117] 20 Treatment space [0118] 21 Side wall [0119] 22 Bottom [0120] 23 Axis of symmetry [0121] 24 Lid [0122] 25 Extension of the sidewall [0123] 3 Stirring unit [0124] 3.1 First agitator [0125] 3.2 Second agitator [0126] 30 Shaft [0127] 31 Axis of rotation [0128] 32 Drive pulley [0129] 33 Mounting holes [0130] 4 Ultrasonic probe (sonotrode) [0131] 41 Longitudinal axis of the ultrasound probe [0132] 42 Ultrasonic oscillator [0133] 5 Drive [0134] 6 Inlet (solids inlet for cement) [0135] 60 Introduction opening [0136] 61 Solids valve [0137] 62 Introduction line for water [0138] 63 Water control valve [0139] 64 Water quantity meter [0140] 7 Flow supply line [0141] 70 Outlet [0142] 71 Metering device [0143] 72 Flange [0144] 8 Level sensor for the level in the cement premixer [0145] 9 Control and/or evaluation unit [0146] 100 Concrete mixer [0147] 200 Water inlet [0148] 300 Admixture container [0149] 400 Cement container [0150] 500 Second cement container [0151] 600 Sand container [0152] 700 Gravel container [0153] 800 Grit container [0154] 1000 Device