Cement pre-mixer, production device of concrete mixture, and production method of cement suspension

Abstract

To provide a cement pre-mixer to produce cement suspension and a production device of concrete mixture provided therewith.SOLUTION: A cement pre-mixer 1 is provided with a treatment container having a treatment space 20, wherein the treatment container is provided with a side wall 21, a bottom part 22, and at least one part of at least one of mixture units 3.1, 3.2 projecting into the treat space 20, the mixture unit is connected with a shaft 30 having a rotational axis 31, the treatment container 2 is provided with at least a part of at least one of an ultrasonic probe 4 projected into the treatment space 20 and an ultrasonic wave oscillator 42 applying ultrasonic waves on the ultrasonic probe 4, comprising at least one of first introducing openings 60 for supplying cement, and an outlet 70 for a fluid supply line 7 to supply premixed cement suspension into a concrete mixer device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cement premixer for producing a cement suspension, as well as an apparatus for producing a concrete mix comprising such a cement premixer, and a method for producing a cement suspension and / or a concrete or mortar mix. [Background technology]

[0002] In the construction industry, precast concrete elements (concrete members prefabricated in a factory) are used. It is very important that the equipment is manufactured and assembled on-site, which means that production is not affected by the weather. Precast concrete elements can be produced with high quality throughout the year. However, the production of concrete with current technology involves a large input of material and energy. To ensure an efficient precast production process, the concrete needs to have a rapid strength development in order to minimize the time required for precast production. Rapid strength development is generally provided by highly reactive Portland cement and heat treatment of the concrete. However, highly reactive Portland cement is very expensive and has a significant carbon dioxide footprint. Additional heat treatment of the concrete can be carried out directly in the formwork or in a heat chamber with hot air, using superheated steam or hot oil. This consumes a significant amount of fuel and therefore CO2 emissions. 2 In addition, about one-third of the heat produced is used for the heat utilization of steel mold processing, so the chemical reaction You can't accelerate it either. This issue is addressed and discussed in Weisheit et al; Betonfertigteilherstellung (Potential for Heat Recovery in Precast Concrete Production), 2018, ibau, Weimar, Germany, Weimar, pp.1146-1153, Volume 1, ISBN 78-3-00-059950-7.

[0003] Furthermore, if the processing temperature of the concrete is too high, it may cause structural damage and result in a significant loss of the durability of the concrete. Therefore, the heat treatment cannot be arbitrarily increased. This is illustrated by Stark, Jochen; Wicht, Bernd (2013): Dauerhaftigkeit von Beton (Durability of Concrete) 2nd Revised Edition Berlin: Springer Vieweg, etc. and others.

[0004] The compressive strength can be increased by using chemical accelerators. However, chemical accelerators have a negative interaction with other concrete components and may not be economical as an alternative to heat treatment. Furthermore, the compressive strength achieved by chemical accelerators is insufficient at low temperatures to maintain a rapid and efficient process.

[0005] German Published Patent No. 10 2017 206 660 describes an apparatus for directly producing a concrete or mortar mixture in a concrete mixer using high-frequency vibrations. These high-frequency vibrations are transmitted to a concrete or mortar mixture containing cement, sand, gravel, grit, and, if possible, further admixtures and water. Russian Patent Nos. 2496748 and 2533516 describe methods for mixing and subjecting water and cement-water mixtures to ultrasonic treatment. Here, these methods differ in the selection of ultrasonic parameters and the resulting physical effects in relation to the present invention.

[0006] The above-mentioned literature describes an intensity of up to 2.5 W / cm 2 which falls within the so-called stable cavitation range. This means that over many acoustic cycles, gas / vapor bubbles grow and vibrate around their position. See the following paper. Mason, Timothy James, Lorimer, John Phillip (2002): Applied sonochemistry. Weinheim: Wiley-VCH Use of ultrasonic waves in chemistry and processing

[0007] In the present invention, a much higher intensity (25 W / cm 2 - 250 W / cm 2 ) is selected to generate so-called transient cavitation. This means that gas / vapor bubbles grow in the ultrasonic field and they release a large amount of energy (heat + pressure) and thus cavitation occurs after only a few acoustic cycles before they exist for only a few acoustic cycles before they exist before they collapse, generating cavitation Furthermore, in Russian Patent Nos. 2496748 and 2533516, an increase in ambient pressure during ultrasonic treatment has been proposed, but the present invention preferably operates at an ambient pressure of (1 bar + / - 0.1 bar).

[0008] Russian Patent No. 2410237 discloses intensities in the range of 7*10 4 W / m 2 - 70*10 4 W / m 2 but does not specify ultrasonic amplification and is also aimed at dispersing and / or grinding cement

[0009] The present invention intends to describe the above types of cement mixers and the above types of methods such that the cement mixer can be integrated into an existing plant. On the other hand, the method using this apparatus enables the development of a higher strength of concrete more rapidly, more efficiently, and cost-effectively Summary of the Invention Means for Solving the Problems

[0010] The present invention solves the above problems by providing a cement premixer having the features of claim 1, providing an apparatus having the features of claim 12, and providing a method having the features of claim 16.

[0011] The cement premixer according to the present invention is composed of a processing container having a processing space, and the processing container is composed of a side wall and a bottom. Further, it includes at least one stirring unit that extends at least partially into the processing space, and this stirring unit is connected to a shaft having a rotation axis. Furthermore, the cement premixer includes at least one ultrasonic probe that extends at least partially into the processing space. Finally, the cement premixer includes at least one ultrasonic oscillator, such as a piezoelectric element, that applies ultrasonic waves to the at least one ultrasonic probe. The ultrasonic probe is particularly configured as a sonotrode and preferably operates in the following range (values referring to T = 2

[0012] 5 °C and normal pressure). Intensity of ultrasonic waves emitted by the ultrasonic probe: 25 W / cm - 250 W / cm 2 - 250 W / cm 2

[0013] When ultrasonic waves are introduced into the medium, the particles and the medium oscillate. This vibration transmits the kinetic energy of the ultrasonic waves. The intensity (I) corresponds to power, for example watts, and is transported per unit area. The unit is power per unit area (e.g., W / cm 2 ). Amplitude of ultrasonic waves emitted by the ultrasonic probe: 15 μm - 500 μm

[0014] The amplitude (u) represents the displacement of the ultrasonic wave (e.g., μm). At a constant frequency, the greater the amplitude, the higher the intensity. The greater the amplitude, the greater the pressure difference during the high - pressure and low - pressure cycles. Frequency of ultrasonic waves radiated by the ultrasonic probe: preferably 10 kHz - 30 kHz

[0015] The frequency (f) represents the vibration rate at the tip of the ultrasonic probe. Since the formation, growth, and collapse of vapor bubbles are time-dependent processes, higher frequencies result in smaller cavitation bubbles. Specific energy input (input to the medium - water): Desirably 25 Ws / ml - 250 Ws / ml

[0016] The above values can be determined electrically in water, for example, using an underwater microphone. The cement premixer according to the present invention comprises at least a first introduction opening for cement supply and an outlet for supplying the cement suspension provided by the cement premixer to a concrete mixing device or a concrete mixer.

[0017] Furthermore, the cement premixer according to the present invention can be provided with a control and / or adjustment device arranged to adjust the operation of the cement premixer within the above operating range. The side wall and the bottom close the processing space laterally and downward. The side wall extends particularly along the rotation axis of the stirring unit. The lid can close at least partially the upper part of the processing space.

[0018] In addition to the supply of cement, water can also be supplied through the introduction opening. Alternatively, water can be supplied through another introduction opening via another inlet pipe. The outlet preferably has an outlet opening. This is preferably arranged at the lower part of the processing container. The outlet can be configured, for example, as a drain pipe with a flanged end connection. A chute can also be considered as an outlet.

[0019] The outlet has an adjustment device, for example, a metering device, particularly a metering valve, by which the supply amount of the cement suspension to the concrete mixer can be regulated. Instead of the valve, an adjustable flap or sluice can also be provided.

[0020] Similarly, the inlet can include a regulating device for regulating the supply amount of cement and / or water and / or other mixtures to the processing vessel. The regulating device can be, for example, a solid valve or an adjustable solid flap. If water and / or further mixtures are supplied to the processing vessel through a separate inlet, for example an inlet pipe, these can also be provided with separate regulating devices. In a cement premixer, the stirring unit is connected to the drive unit via a shaft and can be moved within the processing space by rotation.

[0021] The ultrasonic oscillator may include a controller for adjusting the amplitude of the vibration. By the amplifier and the adjustment of the amplitude that can be performed by this amplifier, as well as the intensity of the resulting ultrasonic vibration, the vibration can be easily adapted to different requirements in the production of different cement suspensions. This setting and the time interval of the ultrasonic treatment correspond to the amount of energy input that adapts to the amount of the cement suspension.

[0022] In a further embodiment of the cement premixer, the cement premixer has a mechanical interface, preferably a flange, via which it can be connected to a concrete mixer, preferably in a way that prevents media leakage.

[0023] For this purpose, the concrete mixer has a counter flange for removably connecting to the flange from the cement premixer as a flange connection. In this case, a drain pipe may be present at the bottom of the processing vessel for transferring the produced cement suspension to, for example, a concrete mixer or a mortar mixer. In another embodiment of the cement premixer, at least one ultrasonic probe extends at least partially into the processing space through the side wall of the processing vessel.

[0024] In a further embodiment of the cement premixer, the processing vessel is axially symmetric and preferably has a rotationally symmetric side wall, the axis of symmetry of which preferably extends parallel to the axis of rotation of the stirring unit. In the case of a rotationally symmetric side wall, the side wall is largely cylindrical. The axis of symmetry and the axis of rotation can coincide.

[0025] In another embodiment of the cement premixer, the side wall has an enlarged portion that extends along the entire circumference of the side wall concentrically with the axis of rotation in the half portion towards the bottom. The enlarged portion extends away from the axis of rotation. In another embodiment, the ultrasonic probe is arranged on the side wall of the extension portion.

[0026] In another embodiment of the cement premixer, at least two ultrasonic probes, preferably three or four ultrasonic probes, project into the processing space and are distributed equiangularly with respect to the axis of symmetry of the side wall. In another embodiment of the cement premixer, at least one ultrasonic probe has a longitudinal axis, and the longitudinal axis is arranged at an angle of 50° to 70°, particularly 55° to 65°, with respect to the axis of symmetry of the side wall of the processing vessel and is directed towards the bottom of the processing vessel.

[0027] In this case, the ultrasonic probe has one end inside the processing space and is directed towards the bottom side of the processing vessel. In another embodiment of the cement premixer, the stirring unit is arranged such that during operation, the intake of solids takes place at the center of the processing space.

[0028] The center of the cement premixer is located around the shaft of the stirring unit. Since the shaft rotates with the tools of the attached stirring unit, a so-called trombe (a type of whirlwind) is formed. This formed trombe transports the material downward to the central or in-region stirring unit elements of the longitudinal axis of the device and causes it to rise again along the edge portion of the cement premixer.

[0029] In this way, the cement suspension can achieve the flow within the medium by passing through the sonotrode (a probe equipped with an ultrasonic vibrator) multiple times. The size of the trombe is determined by the speed and diameter of the stirring unit and can be adapted to the dimensions of the cement premixer.

[0030] In a further embodiment, the cement premixer comprises a control and / or evaluation unit that controls the stirring unit in such a way that it operates at a speed of 200 rpm to 300 rpm. This can be achieved. To ensure good homogenization of the cement suspension, the stirring unit can operate within an operating range of 200 rpm to 300 rpm.

[0031] In another embodiment of the cement premixer, the stirring unit is configured to convey the cement suspension to the bottom and reverse the flow in the processing space during operation. For this purpose, the stirring unit has an inclination of the blades or propellers of the stirring unit of 50° to 55°, preferably 52° to 54°, to favor upward and downward flows.

[0032] In a further embodiment of the cement premixer, the cement premixer has a sensor for detecting the level of the cement premixer. The level measurement can be performed, for example, by radar waves or ultrasonic waves. In a further embodiment of the cement premixer, the control and / or evaluation unit is configured to control the stirring speed of the stirring unit and / or the energy input of the ultrasonic oscillator, preferably the ultrasonic oscillator, as a function of the determined filling level. unit and / or the energy input of the ultrasonic oscillator, preferably the ultrasonic oscillator, as a function of the determined filling level. It is configured to control the energy input amount per unit volume of the cement suspension. However, this energy input amount can also be calculated.

[0033] In particular, the control and / or evaluation unit can control or record the specific energy input amount per unit volume of the cement suspension. However, this energy input amount can also be calculated. This can be achieved. In a further embodiment, the control and / or evaluation unit can also control the supply of cement, water and optionally the mixture. The supply of water is effected, for example, depending on the level measurement of the treatment vessel. The supply of water is effected, for example, depending on the level measurement of the treatment vessel.

[0034] In a further embodiment, the control and / or evaluation unit can also control the flow of the cement suspension, for example as a function of the energy input per unit volume of the cement suspension. In a further embodiment, the control and / or evaluation unit can also control the flow of the cement suspension, for example as a function of the energy input per unit volume of the cement suspension. The invention also comprises an apparatus for producing a concrete mixture comprising a concrete mixer and a cement premixer according to the invention.

[0035] The cement premixer can preferably be connected to the concrete mixer such that fluid can flow therebetween by means of a flange connection between the outlet of the cement premixer and the inlet of the concrete mixer. The connection can be effected mechanically, for example together with a tube fitting which ensures the connection.

[0036] In a further embodiment of the apparatus, the apparatus comprises at least one of a first cement container, a second cement container, a water tank, and / or a mixture container, and the inlet is formed as an inlet pipe or an inlet shaft, which is preferably removably connected by means of a flange connection to at least one of a first cement container of the apparatus and / or one water tank of the apparatus and / or one further container of the apparatus. In a further embodiment of the apparatus, the apparatus comprises at least one of a first cement container, a second cement container, a water tank, and / or a mixture container, and the inlet is formed as an inlet pipe or an inlet shaft, which is preferably removably connected by means of a flange connection to at least one of a first cement container of the apparatus and / or one water tank of the apparatus and / or one further container of the apparatus.

[0037] In a further embodiment of the apparatus, the apparatus comprises a metering device between the cement premixer and the concrete mixer, which metering device regulates the metering of the cement suspension depending on the additional amount of sand, gravel or grit. The amount of sand, gravel or grit (aggregate) supplied is detected by the supply time when the sensor or valve is open. A flow sensor or a weighing belt can also record the amount of the corresponding aggregate.

[0038] The metering device is arranged between the outlet of the cement premixer and the inlet of the concrete mixer. The concrete mixer also comprises an ultrasonic probe capable of introducing ultrasonic vibrations into the mixture of concrete or mortar.

[0039] The present invention is also based on a method for providing a cement suspension, comprising the steps of providing at least cement, water, and optionally at least one admixture in a processing vessel having a processing space, mixing by means of at least one stirring unit protruding at least partially into the processing space to produce a cement suspension, transmitting ultrasonic waves to the cement suspension by means of at least one ultrasonic probe protruding at least partially into the processing space, and discharging the cement suspension via an outlet for further processing, in particular discharging it into a concrete mixer.

[0040] The addition of the admixture is optional. When providing the cement suspension, the admixture may be absent, in which case only cement and water are provided. In particular, in the method for producing a cement suspension, cement, water and optionally an admixture are suspended in the cement premixer according to the present invention.

[0041] In particular, the cement suspension contains 50 to 80 parts by weight of cement, 20 to 40 parts by weight of water, and 0 to 10 parts by weight of an admixture based on the total mass of the cement suspension, and the sum of all components of the cement suspension is 100 parts by weight.

[0042] The above admixtures should be understood as concrete admixtures. These are small amounts of liquid, powder, or granular substances added to the concrete during mixing, based on the cement content. They are raw or hardened concrete DIN EN 206-1 / DIN 1045-2 (current specifications as of July 2019) In concrete according to DIN EN 934-2 (in its current specification) or concrete admixtures approved by the general building authorities may only be used. Aggregates are not generally considered as concrete admixtures.

[0043] In particular, in the method according to the invention, the stirring unit operates at a speed of 50 rpm-500 rpm. In particular, the ultrasonic probe transmits ultrasonic waves in the frequency range of 16 kHz-30 kHz, particularly in the frequency range of 18 kHz-22 kHz, into the cement suspension and has a power of 5 W / cm 2 -100W / cm 2 It has a strength in the range of

[0044] Concrete or mortar is produced in particular by the combination of a cement premixer according to the invention with a concrete mixer. The process can be operated in either a batch or continuous process. In a batch process, the ingredients are added to a processing vessel, mixed and agitated under ultrasound to form an activated cement suspension, which is then transferred, for example, to a concrete mixer. In a continuous process, the raw materials are continuously added to the processing vessel and processed in such a way that an activated cement suspension is continuously withdrawn from the cement premixer and transferred, for example, to a concrete mixer.

[0045] The cement premixer according to the present invention enables particularly efficient homogenization and physical and chemical activation of the cement binder. Since the ultrasonic treatment in the cement premixer is limited to the components of cement, water, and optionally admixtures, the energy generated by the high-frequency ultrasonic oscillator can be directly used to activate the cement binder. As a result, compared to the use of ultrasonic waves in a mixture of cement, water, admixtures, chemically inert sand, gravel or grit, a much-improved use of the input energy amount becomes possible. Only 20% - 35% of the reaction part of concrete, cement, and water forms in the concrete, while the chemically inert part, sand, gravel, and grit form the remaining part. Therefore, in the device according to the present invention, the energy is consumed in a much smaller proportion of the material and is thus used much more efficiently. Also, by generating a cement suspension in the cement premixer, much better mixing than the conventional method can be achieved.

[0046] Due to the improved activation of the reaction part of the concrete and the homogenization of the cement suspension in the cement premixer, a significant reduction in the cement content can be achieved. Furthermore, the heat treatment time can be significantly shortened. For various applications, the heat treatment can be dispensed with completely. Also, the use of the cement premixer according to the present invention accelerates the hardening of the concrete and improves the workability (processing characteristics) of the concrete.

[0047] Also, the cement premixer according to the present invention has the advantage that it can be very easily and cost-effectively integrated as an additional module into an existing concrete mixing plant without much labor. The arrangement of the introduction openings for supplying cement (from the cement meter) and incidentally water, as well as the arrangement of the outlets to the fluid supply line for discharging the finished cement suspension, are particularly suitable for such integration. The mechanical interface, preferably a flange, further improves the efficient integration.

[0048] By using level measurement, the supply rates of cement and / or water can be determined based on changes in the filling level. The combination of using an ultrasonic probe and a stirring unit is particularly advantageous. Cement and water require a considerably higher mixing intensity than the aggregates of concrete for complete pulping. Therefore, it has been shown that an activated cement suspension is produced by the synergistic interaction between the stirring unit and the ultrasonic oscillator.

[0049] The stirring unit according to the present invention can produce a relatively low-speed and homogeneous suspension, especially in combination with the application of ultrasonic energy. This reduces the wear of the stirring unit and at the same time results in lower power consumption.

[0050] As can be seen from the foregoing description, the present invention can be used for various applications in the field of concrete and mortar production. Therefore, the present invention opens up a wide range of applications and uses, for example, in the production of precast concrete elements.

[0051] The modifications and features mentioned and described herein can also be implemented in combinations of two or more modifications or features with each other, provided that the combinations are not mutually contradictory, and such combinations are also encompassed by the present invention.

Brief Description of the Drawings

[0052] One embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Figure 1

Figure 2

Figure 3

Figure 4

Best Mode for Carrying Out the Invention

[0053] The following provisions apply to the entire further description. Although reference signs are described in the figures for the purpose of clarity of the drawings, if they are not explained in the relevant direct description text, the description of the previous figure is referred to.

[0054] As shown in FIG. 1, the cement premixer 1 is composed of a processing container 2 having a processing space 20. The processing space 20 is laterally delimited by a rotationally symmetric side wall 21 and downwardly delimited by a bottom 22. Above, the processing space 20 is closed by a lid 24. A stirring unit 3 provided with a shaft 30 protrudes into the processing space 20, where the shaft protrudes into the processing space through the opening of the lid 24. The mouth part projects into the processing space.

[0055] In the present embodiment, the side wall 21 has an outwardly expanding portion 25 in the lower half. Four ultrasonic probes 4 are attached to this region. In the present embodiment, the stirring unit 3 has two agitators (3.1, 3.2) attached to the shaft 30. The agitating blades of the agitators (3.1, 3.2) are separated so as not to contact the ultrasonic probe 4. The shaft 30 is set in a rotational motion via a rotating disk by an external drive device 5. The shaft 30 has a rotation axis 31 that coincides with the symmetry axis 23 of the side wall 21. The expanding portion 25 is arranged concentrically outside (away from the symmetry axis 23) with respect to the symmetry axis 23. The shaft 30 is set in a rotational motion via a rotating disk by an external drive device 5.

[0056] The shaft 30 has a rotation axis 31 that coincides with the symmetry axis 23 of the side wall 21. The expanding portion 25 is arranged concentrically outside (away from the symmetry axis 23) with respect to the symmetry axis 23. Laterally, the ultrasonic probe 4 forms an angle of 60° with the vertical symmetry axis 23 of the side wall 21, and the ultrasonic probe 4 is directed downward toward the bottom 22. The ultrasonic probe 4 is directed downward toward the bottom 22.

[0057] In this embodiment, the control and / or evaluation unit 9 records the parameter filling level, the energy input by the ultrasonic probe, and the amount of water added by the water meter 64. The control and / or evaluation unit 9 controls the drive 5 of the stirring unit 3 (setting the rotation speed of the stirring unit 3), the ultrasonic oscillator 42 in terms of ultrasonic amplitude and frequency (in this case, the energy input amount is determined by the control and / or evaluation unit 9), the solid matter valve 61, the water control valve, and the discharge of the suspension through the metering valve 71.

[0058] Furthermore, the lid 24 has an introduction opening 60, and a pipe 6 for supplying solid matter protrudes into the introduction opening. The pipe 6 is controlled via the solid matter valve 61. In this embodiment, cement is added, and the addition of cement is controlled via the solid matter valve 61. The water introduction line 62 for water is arranged through the side wall 21. Therefore, water can be added via the water control valve 63 to produce a cement suspension. In this embodiment, the amount of water added is determined by the water meter 64.

[0059] The level sensor 8 determines the level in the treatment space 20. This level measurement is used by the control and / or evaluation unit, for example, as a basis for controlling the addition of water. At the bottom 22 of the treatment container 2, there is an outlet 70 for the fluid supply line 7 for discharging the completed cement suspension to the concrete mixer. The discharge of the cement suspension is controlled as a function of the energy input amount per unit volume. The discharge line 7 is provided with a flange 72, and the discharge line 7 can be quickly and easily connected to the concrete mixer using the flange.

[0060] ​​​​​​​​FIG. 2 is a plan view of the embodiment of FIG. 1, in which the arrangement of four ultrasonic probes 4 at 90° angles to each other on the side wall 21 is particularly visible. The view into the treatment space 20 shows the ultrasonic probes 4. 2 shows that the probe 4 is oriented towards the axis of symmetry 23 of the side wall 21. Mounting holes allow the flange to be connected to a drive device, enabling the driving of the shaft 30 and thus the stirring units 3.1 and 3.2.

[0061] FIG. 3 shows a schematic diagram of the steps of the conventional method. In a concrete mixer 100, water is poured from a water inlet 200, admixture is poured from an admixture container 300, and the first cement container or the second cement container 310 is poured. Cement is poured from cement containers 400 and 500 and aggregates (sand, gravel and / or grit) are poured from corresponding containers 600, 700 and 800. The components are mixed directly in the concrete mixer to obtain the concrete mixture.

[0062] In contrast to this conventional mode of operation, in the method according to the present invention according to the embodiment shown in Figure 4, a cement suspension is generated separately in the cement premixer 1. In this process, water from the water inlet 200, cement from the cement containers 400 and / or 500, and optionally admixture from the admixture container 300 are processed in the cement premixer 1 to form a cement suspension. The cement suspension is transferred from the cement premixer 1 to the concrete mixer 100, where aggregates from the corresponding containers 600, 700, 800 are added to produce a concrete mix, which is then further processed.

[0063] The combination of the cement premixer 1 and the concrete mixer 100 forms an apparatus 1000 for producing a concrete mixture. The preparation of the activated cement suspension may be operated as either a batch or a continuous process. Example A concrete was produced by the method according to the invention for producing a cement suspension.

[0064] As shown in Figure 1, the laboratory-scale cement mixer according to the present invention has a diameter ranging from 400 mm to 493 mm at its widest point, a total height of 550 mm, and four ultrasonic probes (sonotrodes) distributed at 90° to each other around the symmetry axis of the processing vessel. The processing space contains 45 kg of cement, 20 liters of water, and 0.5 kg of superplasticizer (admixture). are contained.

[0065] The stirring unit operates at a speed of 250 revolutions per minute. Vibration is transmitted to the processing space through the sonotrode in a low ultrasonic range of 20 kHz. By using ultrasonic processing and mixing tools, rapid and efficient homogenization of the cement suspension is achieved within 180 seconds.

[0066] The cement suspension thus produced is transferred to a concrete mixer. Here, 225 kg of aggregate is added and the concrete is mixed. The fluidity of this concrete is significantly increased compared to the conventional manufacturing method, and the early strength is considerably improved. Especially in the manufacture of precast concrete components, it can be manufactured in a shorter time, leading to a decisive advantage and better quality precast components.

Explanation of Reference Numerals

[0067] List of symbols 1 Cement mixer 2 Processing vessel 20 Processing space 21 Side wall 22 Bottom 23 Symmetry axis 24 Lid 25 Enlarged part of the side wall 3 Stirring unit 3.1 First agitating mixer 3.2 Second agitating mixer 30 Shaft 31 Rotation axis 32 Driving pulley 33 Mounting holes 4 Ultrasonic probe (sonotrode) 41 Longitudinal axis of the ultrasonic probe 42 Ultrasonic oscillator 5 Driving device 6 Inlet (solid material inlet for cement) 60 Introduction opening 61 Solid material valve 62 Introduction line for water 63 Water control valve 64 Water meter 7 Fluid supply line 70 Outlet 71 Measuring device 72 Flange 8 Level sensor for the level in the cement premixer 9 Control and / or evaluation unit 100 Concrete mixer 200 Water inlet 300 Admixture container 400 Cement container 500 Second cement container 600 Sand container 700 Gravel container 800 Grit container 1000 Device

Claims

1. A cement premixer (1), comprising: A processing vessel (2) having a processing space (20) and including a side wall (21) and a bottom (22); at least one stirring unit (3; 3.1, 3.2) which projects at least partially into the treatment space (20) and is connected to a shaft (30) having an axis of rotation (31); At least one ultrasonic probe (4) protruding at least partially into the treatment space (20); 、 At least one ultrasonic oscillator for applying ultrasonic waves to at least one ultrasonic probe (4). A container (42), 25W / cm ２ -250W / cm ２ and an amplitude of 15 μm-500 μm, The cement premixer has at least one first inlet opening (60) for supplying cement and a flow inlet opening (62) for injecting the cement suspension provided by the cement premixer (1) into the concrete mixer. A cement premixer having an outlet (70) for a supply line (70).

2. The cement premixer (1) is connected to the concrete mixer (100).

2. The cement premixer (1) of claim 1, further comprising a mechanical interface, preferably a flange (72), for connecting the premixer to the cement premixer.

3. At least one ultrasonic probe is inserted at least partially through the side wall (21) of the treatment vessel (2).

2. The cement premixer (1) according to claim 1, wherein the premixer (1) partially projects into the treatment space (20).

4. The treatment vessel (2) has an axisymmetric, preferably rotationally symmetric, side wall (21).

3. A cement premixer (1) according to claim 1 or 2, wherein the axis of symmetry (23) preferably extends parallel to the axis of rotation (31) of the stirring unit (3; 3.1, 3.2).

5. 5. A cement premixer (1) according to claim 4, characterized in that the side wall (21) has an enlarged portion (25) in its half portion towards the bottom (22), said enlarged portion (25) extending along the entire circumference of the side wall (21) concentrically with the axis of symmetry (23).

6. 6. A cement premixer (1) according to claim 1, wherein at least two ultrasonic probes (4), preferably three or more ultrasonic probes (4), protrude into the treatment space (20) and are distributed with respect to one another at approximately the same angle around the axis of symmetry (23) of the side wall (21).

7. 7. The method according to claim 1, wherein the ultrasonic probe (4) is arranged in the region of the enlarged portion (25) of the side wall. The cement premixer (1) according to the above.

8. At least one ultrasonic probe (4) has a longitudinal axis (41), are arranged at an angle of 50° to 70°, in particular 55° to 65°, to the axis of symmetry (23) of the side wall (21) of the treatment vessel (20) and are aligned in the direction of the bottom (22) of the treatment vessel (2).

2. A cement premixer (1) according to any one of the above.

9. 9. The cement premixer (1) according to any one of claims 1 to 8, characterized in that the cement premixer has a control and / or evaluation unit (9) for controlling the stirring unit (3; 3.1, 3.2) to operate at a speed of 200 to 300 revolutions per minute.

10. 10. The method according to claim 1, further comprising a level sensor (8) for detecting the level of the cement premixer. The cement premixer (1) according to any one of the above.

11. 10. The cement premixer (1) according to claim 9, wherein the control and / or evaluation unit (9) is configured to control the stirring speed of the stirring unit and / or to control the energy input of an ultrasonic generator, more preferably of an ultrasonic generator, as a function of the determined filling level.

12. An apparatus (1000) for producing a concrete mixture, comprising a concrete mixer (100) and a cement premixer (1) according to any one of claims 1 to 11.

13. 13. The apparatus (1000) of claim 12, wherein the cement premixer (1) is fluidly connected to the concrete mixer (100), preferably by a flange connection (72) between an outlet (60) of the cement premixer (1) and an inlet of the concrete mixer (100).

14. The apparatus includes a first cement container (400), a second cement container (500), a water inlet (200), and 14. The apparatus (1000) according to claim 12 or 13, further comprising at least one of a first cement container (400) and / or a water tank (200) and / or an admixture container (300), and the inlet (6) is formed as an inlet pipe or an inlet shaft detachably connected, preferably by a flange connection, to at least one of the first cement container (400) and / or the water tank (200) and / or the admixture container (300) of the apparatus (1000).

15. 15. An apparatus (1000) according to any of claims 12 to 14, wherein a metering device (71) between the cement premixer (1) and the concrete mixer (100) regulates the metering of the cement suspension as a function of the amount of sand, gravel or grit supplied.

16. 1. A method for delivering a cement suspension comprising the steps of: A treatment vessel (2) having a treatment space (20) for treating cement, water and at least one optional admixture. and providing At least one stirring unit (3) protruding at least partially into the treatment space (20) to produce a cement suspension; At least one ultrasonic probe (4) protruding at least partially into the treatment space (20) transmitting ultrasonic oscillations thereto; A method for delivering a cement suspension comprising the step of discharging the cement suspension through an outlet (60) for further processing, in particular in a concrete mixer.

17. 17. A method as claimed in claim 16, wherein the discharge of the cement suspension is performed according to a specific energy input per unit amount of cement suspension.

18. The cement suspension is 50 to 80 parts by weight of cement; 20 to 40 parts by weight of water; 18. A method of delivering a cement suspension as claimed in claim 16 or 17, comprising from 0 to 10 parts by weight of admixture based on the total mass of the cement suspension, the total of all components of the cement suspension adding up to 100 parts by weight.

19. 19. A method for delivering a cement suspension according to any one of claims 16 to 18, wherein ultrasonic vibrations are generated by at least one ultrasonic generator (42) and ultrasonic waves are applied to at least one ultrasonic probe (4).

20. The stirring unit (3; 3.1, 3.2) rotates at 50-500 revolutions per minute, preferably at 100-1500 revolutions per minute.

20. A method as claimed in any one of claims 16 to 19, operating at a speed of 200 rpm to 300 rpm.

21. A method according to any one of claims 16 to 20, wherein the ultrasonic probe transmits ultrasonic waves into the cement suspension in a frequency range of 16kHz-30kHz, in particular in a frequency range of 18kHz-22kHz.

22. 22. A method of mixing concrete or mortar using an apparatus according to any one of claims 16 to 21.

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