EP4311640A1 - Concrete compacting device with measurement of the compaction progress - Google Patents

Abstract

A concrete compaction device is specified, with a vibrating housing (4) for immersing in flowable concrete, with an unbalance exciter (6) driven by an electric motor (5) and arranged in the vibrating housing (4), with a current detection device (11) for detecting the electrical current that is recorded by the electric motor (5), and with an evaluation device (12) for determining a working state of the concrete compaction device based on the currently detected electrical current, the working state being selected from the group: positioning the vibrating housing (4) in the air, immersing the vibrating housing (4) in the concrete, carrying out a compaction process with the vibrating housing (4) immersed in the concrete, removing the vibrating housing (4) from the concrete, and the evaluation device (12) is designed to measure all of the to recognize the above-mentioned working states.

Description

The invention relates to a concrete compaction device with a device for measuring the progress of compaction. In particular, the invention relates to an internal vibrating device, such as an internal vibrator for concrete compaction.

It is known that fresh concrete must be compacted after being placed in a formwork in order to achieve a certain density while avoiding gas pores or so-called "gravel nests". A 10% lower density of concrete results in a halving of the compressive strength. However, excessive compaction of the concrete can lead to segregation of the concrete with zoned accumulation of cement paste.

Larger concrete pours are usually done manually using vibrators or shakers, such as. B. hose or rod vibrators. condensed. Such vibrators are internal vibrators in which an imbalance is driven by an electric motor inside a vibrating bottle (vibrator housing) that is immersed in the fresh concrete, which creates vibrations that compact the concrete. While concrete as a building material is subject to various and strict quality controls, the correct compaction of the concrete depends significantly on the individual skills of the operator of the internal vibrator. He alone determines whether an optimal and uniform compaction result is achieved. However, since the individual skills of different operators can naturally vary greatly, the quality of compaction can also vary considerably, which in certain cases leads to an inadequate compaction result and thus to insufficient concrete strength.

From the GB-A-1097651 An internal vibrator is known in which the power consumption of an electric motor driving an unbalanced mass is viewed as an indication of the degree of compaction of the concrete to be compacted. Measuring power consumption and its rough interpretation do not allow a reliable determination of the degree of compaction.

From the EP 1 165 907 B1 an internal vibrator with a measuring system for determining the compaction progress in concrete is known. The vibrations on the vibrating bottle are recorded, from which conclusions can be drawn about the compaction effect. However, the use of appropriate acceleration sensors on the vibrating bottle is difficult to implement in practice due to the strong vibrations and harsh environmental conditions. In addition, additional signal lines are necessary in a mechanically highly stressed environment.

Measuring and documenting the progress of compaction is still hardly possible in concrete technology. The compaction duration and the number of immersion processes with an internal vibrator as well as the choice of immersion points are usually based on the user's experience.

The invention is therefore based on the object of specifying a concrete compaction device, in particular an internal vibrating device, in which the degree of compaction of the currently compacted concrete can be reliably recorded.

The object is achieved according to the invention by a concrete compaction device with the features of claim 1. Advantageous embodiments are specified in the dependent claims.

A concrete compaction device is specified, with a vibrating housing for immersion in flowable concrete; an unbalance exciter driven by an electric motor, which is arranged in the vibrator housing; a current detection device for detecting the electric current consumed by the electric motor; and with an evaluation device for determining a working state of the concrete compaction device based on the currently detected electrical current; wherein the working state is selected from the group of positioning the vibrating housing in the air (operating the electric motor at idle), immersing the vibrating housing in the concrete, carrying out a compaction process with the vibrating housing immersed in the concrete, emerging the vibrating housing from the concrete; and wherein the evaluation device is designed to recognize all of the working states mentioned.

The electric motor can be arranged together with the unbalance exciter in the vibrating housing. In one variant, only the unbalance exciter is arranged in the vibrating housing, while the electric motor is arranged spatially separated from the vibrating housing in its own housing. In this case, the torque of the electric motor is transmitted via a flexible shaft to the unbalance exciter in the vibrator housing.

The working states can be recognized in particular based on the precisely recorded current curve with a correspondingly high sampling rate. While playing Not only the current current value, but also the change in the current values over time (e.g. detectable with the help of the sampling rate) plays a role, so that specific current profiles can be recorded and recognized. Due to the tendency of the current curve, the evaluation device can recognize the different working states and - where appropriate - also distinguish them from one another. For this purpose, the currently recorded current profile can be compared with current values and current curves or gradients, for example with known values or patterns, in order to be able to draw conclusions about the respective working status.

The working states “positioning the vibrating housing in the air” and “operating the electric motor at idle” are to be regarded as identical. In this case, the vibrator housing is still exposed to air and is not yet immersed in the concrete. The electric motor can be operated at idle or almost at idle, as the unbalance exciter can still rotate freely.

The compaction work begins with the working condition “immersion of the vibrator housing into the concrete”. The vibrating housing is successively lowered into the flowable concrete, which absorbs and dampens the vibrations of the vibrating housing. In the train, the current consumption by the electric motor is increased in order to be able to drive the unbalance exciter as before.

In the working state "carrying out a compaction process", the vibrating housing is largely completely immersed in the concrete and is held essentially stationary by the user at one point, so that the vibrating housing remains in the concrete. Due to the compaction effects in the concrete, the damping effect of the concrete on the vibrator housing changes, which in turn has an effect in the form of counterforces or countertorques acting on the unbalance exciter. This changes the current consumption by the electric motor, which can be recorded by the evaluation device.

In the working state "Exiting the vibrating housing from the concrete", the vibrating housing is pulled out of the concrete and raised. This means that the vibrating housing can vibrate more and more freely as the damping effect of the concrete gradually decreases. Accordingly, the electric motor can rotate freely again, so that the power it consumes is reduced and power consumption is reduced.

The evaluation device can use the respectively sampled current values and the gradients of the current values or the tendency of the current value development to recognize which working state the internal vibrator is in. During the compaction process ("carrying out a compaction process"), the evaluation device can detect the compaction state of the concrete based on the current profile, i.e. the current values and the gradient curve, and compare it with limit values, for example. If a certain limit value is reached, this is taken as a criterion that the concrete has been sufficiently compacted at this point.

In one variant, the evaluation device can recognize the working states “electric motor switched off” and “electric motor and/or unbalance exciter defective” as further working states. In this case, the electric motor either does not consume any power or a current consumption or a current profile is detected that does not fit into the schemes for the normal working states, e.g. a current consumption that is too low or too high.

The current detection device can be designed to detect the electrical voltage applied to the electric motor in addition to the current. This allows the measurement accuracy to be further increased.

The current detection device can be designed to detect the current with a sampling interval, wherein the sampling interval can be less than 5 s. In particular, the sampling interval can be less than 2 s, less than 1 s, less than 0.5 s or 1/10 s or less.

The evaluation device can be designed to determine the respective working state, taking into account the currently detected current profile with a currently detected electrical current and/or a respective determinable current gradient. The current gradient is a change in the current current value over time. Depending on the recorded absolute current value, possibly in conjunction with the current gradient, the evaluation device can thus record the working condition and also the degree of compaction in the concrete. The current value and current gradient can be evaluated together or separately. An example of the evaluation will be explained later in the description of the figures.

An interpretation device can be provided for interpreting the current curve during the working state "carrying out a compression process" is recognized, wherein the interpretation device can be designed to evaluate the current current gradient for interpreting the current profile, and wherein an approach of the current gradient to the values of zero is considered a criterion for compression progress. As the current gradient approaches zero, this means that the current current curve becomes flatter. This can be observed in the course of the compression process, whereby an approach of the current gradient towards zero means that the currently consumed current hardly changes. This is seen as a criterion for ensuring that the concrete in the area of the vibrating bottle has been sufficiently compacted.

A limit value for the approach of the current gradient to the value zero can be specified, and a signaling device can be provided to generate a signal for an operator when the limit value is reached by the current gradient. It is therefore not absolutely necessary that the current gradient actually reaches the value zero. Rather, an approach to the value zero and thus reaching the limit value may be sufficient. Reaching the limit value means that the concrete has been sufficiently compacted at that point. This condition can be determined by the interpretation device, which then gives the operator a signal via the signaling device that the concrete has been sufficiently compacted so that the operator can move the vibrating housing to another location in the concrete.

A power supply line can be provided for supplying the electrical current to the electric motor. In particular, the current detection device can be arranged in the area of the power supply line in order to be able to detect the electrical current that is absorbed by the electric motor.

A power source can be provided for the electric motor, which has an electrical energy storage and/or a power grid. The electrical energy storage can be, for example, a battery.

In particular, the electrical energy storage can have a portable battery, which is carried on the back of an operator like a backpack, for example. The electrical power for the concrete compaction device can therefore only be obtained from the battery carried by the operator. The operator is therefore self-sufficient and does not need any external power supply connections.

The current detection device, the evaluation device and the interpretation device can be arranged on the battery or coupled to the electronics (battery management system) of the battery. In particular, these devices can also be (partially) integrated into the battery management system, such as the current detection device.

In particular, the electrical energy storage can have control electronics, wherein the current detection device and/or the evaluation device and/or the interpretation device can be coupled to the control electronics. The current detection device, the evaluation device and/or the interpretation device can also be arranged spatially on the control electronics or the energy storage device.

Fig. 1

in schematischer Darstellung einen Innenrüttler als erfindungsgemäße Betonverdichtungsvorrichtung; und

Fig. 2

ein Beispiel für die Änderung der Stromaufnahme in Abhängigkeit von unterschiedlichen Arbeitszuständen einer Betonverdichtungsvorrichtung.

These and other advantages and features of the invention are explained in more detail below using examples with the aid of the accompanying figures. Show it:

Fig. 1

a schematic representation of an internal vibrator as a concrete compaction device according to the invention; and

Fig. 2

an example of the change in current consumption depending on different working states of a concrete compaction device.

Fig. 1 shows a schematic representation of a concrete compaction system with an internal vibrator 1 and an energy device 2.

The internal vibrator 1 has an operating hose 3, at one end of which a vibrating bottle 4 serving as a housing is attached. Inside the vibrating bottle 4, an electric motor 5 is provided, which rotates an unbalance exciter 6. The unbalance exciter 6 can, for example, be an unbalance shaft on which an unbalance mass is attached eccentrically, so that when the unbalance shaft rotates, vibrations are generated which are introduced into the concrete to be compacted via the outer housing wall of the vibrating bottle 4. The structure of such a vibrating bottle 4 with an electric motor 5 and unbalance exciter 6 is known per se.

In a variant not shown, which is also known per se, the electric motor 5 is not arranged in the vibrating bottle 4, but in its own housing, spatially separated from the vibrating bottle 4. In this case extends between the electric motor 5 and the unbalance exciter 6 arranged in the vibrating bottle 4 there is a flexible shaft via which the torque of the electric motor 5 can be transmitted to the unbalance exciter 6. The flexible shaft is surrounded by the operating hose 3, which can also be used to guide the vibrating bottle 4.

The in Fig. 1 The operating hose 3 shown can be several meters long, so that the operator can hang the vibrating bottle 4 over a greater distance in the concrete to be compacted during the compaction work. The Fig. 1 is otherwise not to scale and does not reflect the real length of the operating hose 3.

At the end of the operating hose 3 opposite the vibrating bottle 4, a switching device 7 is attached, via which the electric motor 5 can be switched on and off. The switching device 7 can also serve as a coupling point for a power line 8 (power cable). The electrical supply lines of the power line 8 are guided inside the operating hose 3 to the vibrating bottle 4, so that the operating hose 3 also takes on the function of a protective hose. At the end of the power line 8 opposite the switching device 7, one in the Fig. 1 Plug, not shown, can be provided in a manner known per se.

The plug can be inserted into the energy device 2. At the one in the Fig. 1 In the example shown, essential parts of the energy device 2 can be arranged on a carrying device, not shown, which can be carried by a user, for example on his back, with the aid of carrying straps, similar to a backpack. The carrying device can have a supporting frame that reliably supports the components attached to it. This is also the case, for example DE 10 2018 118 552 A1 described. The energy device 2 has a battery 9 as an electrical energy storage device. The battery 9 can be exchangeable and can be replaced with a fresh battery 9 when it is exhausted.

Instead of the battery 9, it is also possible to provide an electrical supply via the public network or an existing network at the construction site.

Furthermore, part of the energy device 2 can be a converter 10, which in particular converts the current drawn from the battery 9 in terms of voltage and frequency in a manner suitable for the electric motor 5. This transformed one Electricity is then supplied from the converter 10 to the electric motor 5 via the power line 8.

Symbolically, a current detection device 11, an evaluation device 12 and an interpretation device 13 are also provided on the energy device 2. These components can also be arranged elsewhere on the internal vibrator. However, their arrangement in the vicinity of the battery 9 or the converter 10 is useful in order to precisely record and interpret the current drawn by the electric motor 5.

The current detection device 11, the evaluation device 12 and the interpretation device 13 do not have to be present as physically separate components. Rather, they can also be arranged in the battery 9 or in the battery management of the battery 9 or in the converter 10 or elsewhere. For example, the evaluation device 12 and the interpretation device 13 can also be spatially arranged elsewhere, for example as a software application on a smartphone that is carried by the operator of the internal vibrator. In this case, a communication path or interface must be provided in order to transmit the current values recorded by the current detection device to the evaluation device 12.

The current detection device 11 is used to detect the electrical current that is absorbed by the electric motor 5. It is possible to record the current in short sampling intervals.

The measurement results of the current detection device 11 are passed on to the evaluation device 12, which can detect a working state of the internal vibrator based on the currently detected electrical current (current values and current curve or current gradient), as described below using Fig. 2 is explained.

The interpretation device 13 is intended to interpret the flow curve during a compression process. In particular, the interpretation device 13 should recognize and classify the compression state during the compression process.

If the interpretation device 13 determines that the concrete has currently been sufficiently compacted, a signal device (not shown) can be used Signal can be given to the operator of the internal vibrator 1 so that he ends the compaction at the corresponding point and continues it at another place.

The information about the compaction state can be communicated to the operator in various ways. For example, the corresponding data can be displayed to the operator via assistance systems, e.g. applications installed on smartphones. In addition, it is also possible to easily record the measurement results for later documentation.

Fig. 2 shows an example of the course of the current drawn by the electric motor 5 over time during different working states of the internal vibrator 1. The respective current values can be recorded by the current detection device 11 with short sampling intervals.

During phase a, the internal vibrator runs in the air and is not immersed in the concrete (idling phase, operating the electric motor at idle, positioning the vibrator housing in the air). In this phase, the current consumed is constantly low.

While the vibrator housing is immersed in the concrete (phase b), the current consumption increases and reaches a detectable maximum.

If the internal vibrator then remains in the concrete (compacting process), the concrete is compacted in the area of effect of the vibrating bottle 4 (phase c). A partially decreasing current curve can be seen, with a negative current gradient.

Based on the changing current gradient (current drop), the progress of the compression process can be deduced by the evaluation device 12 in conjunction with the interpretation device 13. The further the compression progresses, the flatter the curve becomes, i.e. the current gradient approaches zero. The current drawn always remains higher than in the idling phase in the air (phase a), so that the states of idling (phase a) and "immersed" or "compression" (phase c) can be clearly distinguished from one another.

When the vibrating bottle 4 emerges from the concrete (phase d), a brief increase in current can be observed due to the change in position of the vibrating bottle 4. The current drawn then drops to the level corresponding to idle Value returns as soon as the internal vibrator is exposed to air again. Finally, the current consumption goes back to the idle phase (phase e).

In particular, in the case of an energy device that is designed to be portable in a backpack system and has an energy storage device that can be used to operate internal vibrators, measuring devices are usually already present, for example in the battery control electronics, with which the input power in the form of current and voltage is used to operate the internal vibrator can be measured. Additional sensors, especially in the vibrating bottle or the protective hose, are not required.

Due to the high measurement accuracy and sampling rate, it is possible to draw conclusions from the current curve about the working status (idle, immersion, dwell, emergence) as well as the compaction progress of the internal vibrator in the concrete. To determine the respective working status, the measured values or their progressions and changes are compared with known values or patterns.

The measurements can be carried out in a suitable manner with battery-operated internal vibrators, but also with mains-operated internal vibrators.

Claims (10)

Concrete compaction device, with - a vibrator housing (4) for immersion in flowable concrete; - an unbalance exciter (6) driven by an electric motor (5) which is arranged in the vibrator housing (4); - a current detection device (11) for detecting the electrical current that is absorbed by the electric motor (5); and with - an evaluation device (12) for determining a working state of the concrete compaction device based on the currently detected electrical current;
where - the working state is selected from the group + Positioning the vibrator housing (4) in the air + Immerse the vibrator housing (4) in the concrete + Carrying out a compaction process with the vibrator housing (4) immersed in the concrete + Exiting the vibrator housing (4) from the concrete; and where - The evaluation device (12) is designed to recognize all of the working states mentioned. Concrete compaction device according to claim 1, wherein further working states can be detected by the evaluation device (12): - Electric motor (5) switched off - Electric motor (5) and/or unbalance exciter (6) defective. Concrete compaction device according to one of the preceding claims, wherein the current detection device (11) is designed to detect the electrical voltage applied to the electric motor (5) in addition to the current. Concrete compaction device according to one of the preceding claims, wherein - the current detection device (11) is designed to detect the current with a sampling interval; and where - the sampling interval is less than 5 seconds. Concrete compaction device according to one of the preceding claims, wherein the evaluation device (12) is designed to determine the respective working status to be determined taking into account the currently detected electrical current and/or a respective determinable current gradient. Concrete compaction device according to one of the preceding claims, wherein - an interpretation device (13) is provided for interpreting the current profile while the working state “carrying out a compression process” is recognized; - the interpretation device (13) is designed to evaluate the current current gradient for interpreting the current curve; and where - an approach of the current gradient to the value zero is considered a criterion for compression progress. Concrete compaction device according to one of the preceding claims, wherein - a limit value is specified for the current gradient to approach zero; and where - A signaling device is provided for generating a signal for an operator when the limit value is reached by the current gradient. Concrete compaction device according to one of the preceding claims, with a power supply line (8) for supplying the electrical current to the electric motor (5). Concrete compaction device according to one of the preceding claims, wherein a power source for the electric motor has an electrical energy storage (9) and / or a power network. Concrete compaction device according to one of the preceding claims, wherein - the electrical energy storage (9) has control electronics; and where - the current detection device (11) and/or the evaluation device (12) and/or the interpretation device (13) are coupled to the control electronics.

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