FEEDING DEVICE FOR A CONCRETE MIXING PLANT

Description

[0001] The invention relates to a feeding device for a concrete mixing plant.

[0002] Concrete mixing plants are used to produce concrete. They consist of a rock silo and a mixing unit for mixing aggregate stored in the silo with cement and water to produce concrete. The fresh concrete produced in this way can then be delivered to a truck mixer. Modern concrete mixing plants typically use multi-chamber silos, in which different aggregates can be stored in the chambers, which can be used to produce different concrete mixtures.

[0003] In order to feed aggregate from a truck or mobile construction machine to a concrete mixing plant, concrete mixing plants typically include a feeding system whose main components are a feed hopper and a generally multi-part transport system. Common transport systems include a vibrating chute, a bucket elevator, and a branch conveyor. The vibrating chute is used to convey the aggregate to the bucket elevator, which represents the core of the transport system and bridges most of the distance between the feed hopper outlet and the silo inlet. The branch conveyor then transports the aggregate from the bucket elevator to the silo inlet. In multi-chamber silos, a rotary distributor belt is typically connected to the branch conveyor to direct the aggregate to a specific silo chamber.

[0004] In order to achieve a large feed volume per unit of time and to utilize a bucket elevator with a conveying capacity of, for example, 300 m³ / h, so-called double feed hoppers with two outlet areas and two vibrating feeders were proposed in the prior art. However, in order to utilize the maximum conveying capacity with such solutions, the double feed hopper must be fed evenly, which means that the truck or mobile construction machine must empty the same amount of aggregate material into the different areas of the hopper. If the filling is uneven, the conveying capacity of both vibrating feeders and consequently the conveying capacity of the bucket elevator is not fully utilized over the entire time. A further disadvantage of such solutions is that when changing material, the double feed hopper can only be refilled after it has been completely unloaded.

[0005] Another problem area when feeding multi-chamber silos is the necessary follow-up times and downtimes during the positioning process of the rotary distributor belt when a material change is required during feeding. Generic feeding devices for concrete mixing plants are known, for example, from CN 109 465 966 ​​A, CN 108 381 781 A, JPH06 23734 A, or CN 210 820 236 U, whereby CN 210 820 236 U discloses a feeding device for a concrete mixing plant according to the preamble of claim 1.

[0006] The object of the invention is to overcome these disadvantages of the prior art and to increase the efficiency of feeding devices.

[0007] The above object is achieved by the combination of the features of claim 1.

[0008] Accordingly, the invention relates to a feeding device for a concrete mixing plant with a feed hopper for an aggregate and a multi-part

[0009] A transport system for conveying aggregate from an outlet of a feed hopper to an inlet of a multi-chamber silo, wherein the multi-part transport system comprises, in a staggered arrangement, an initial transport device, a central transport device, and a final transport device. Furthermore, the feeding device has at least two feed hoppers, and the initial transport device is configured to convey aggregate from the outlets of the at least two feed hoppers toward the central transport device; and wherein the final transport device has a distribution device that is rotatable and reversible in a clockwise and counterclockwise direction about a vertical axis. The distribution device can be a rotary distributor belt.Furthermore, the feeding device according to claim 1 comprises a material detector in the area of ​​the initial transport device for detecting complete emptying of the feed hopper. The material detector can be a material sensor. Alternatively or additionally, other types of detectors, such as an optical sensor, can also be used.

[0010] These inventive measures enable an increase in efficiency. Firstly, the two feed hoppers can be alternately fed with aggregate, allowing the maximum conveying capacity of the transport system to be utilized more fully in practice and reducing the waiting time when changing materials. Furthermore, by appropriately positioning the material detector in the area of ​​the initial transport device, complete emptying of the feed hopper or one of the feed hoppers can be reliably detected. This means that if the target chamber of the multi-chamber silo needs to be changed, the required follow-up time until the final transport device can be changed can be determined more precisely. The distribution device, which can be rotated and reversible in both directions, enables the time required for changing the target chamber of the multi-chamber silo to be optimized.

[0011] The central transport device is preferably a bucket elevator. In one embodiment, the central transport device and the transport system can have a total conveying capacity of greater than 200 m³ / h, in particular greater than 300 m³ / h. Of course, embodiments with lower conveying capacities are also possible.

[0012] Furthermore, the invention according to claim 1 provides that the initial transport device has a belt conveyor and the belt conveyor is designed to transport aggregate from the at least two feed hoppers.

[0013] According to the present invention, the initial transport device has at least two transfer devices for conveying aggregate from the outlets of both feed hoppers onto belt conveyors. It is preferred that the two transfer devices can be controlled individually. The transfer devices are preferably vibrating chutes. If, for example, only one of the feed hoppers is full, a stronger vibration and thus a higher conveying capacity can be selected at the associated vibrating chute than if both feed hoppers are full. Thus, regardless of whether one or both feed hoppers are completely full, the maximum conveying capacity of the transport system can be utilized as fully as possible.

[0014] According to the present invention as defined in claim 1, the material detector is arranged on the belt conveyor in the region of the at least two transfer devices, in particular directly downstream of the at least two transfer devices in the conveying direction. The material detector can be arranged above the belt conveyor. Such positioning has proven particularly advantageous. In particular, at least two individual material detectors can be provided, with each of the material detectors being assigned to one of the feed hoppers. Each of the material detectors is arranged in particular in the region of the belt conveyor (preferably above the belt conveyor) and directly downstream of the respective transfer device of the assigned feed hopper. In this way, the emptying of each feed hopper can be determined individually.

[0015] In a typical embodiment, the final transport device comprises a conveyor, for example, a branch conveyor, for conveying aggregate from the central transport device to the distribution device. The central and final transport devices can be part of an S-conveyor.

[0016] In a variant of the invention, the sections of the distribution device that extend in opposite directions from the area through which its vertical axis of rotation runs are of equal length. The vertical axis of rotation thus extends through the center of the distribution device. The conveying means, in particular the stub conveyor, preferably empties the aggregate onto the distribution device in this area.

[0017] Furthermore, the feeding device can be provided with a reading device for automatically reading information about an aggregate to be fed into the feed hopper. For example, the reading device can be designed to automatically read QR codes, RFID tags, or other electronically generated labels. A control unit of the feeding device can use the read information to define a specific target chamber for the material in the multi-chamber silo.

[0018] According to the invention, the feeding device has a control unit which is designed to detect a complete emptying of a feed hopper on the basis of a signal from the material detector, to determine a follow-up time and, after the follow-up time has elapsed, to initiate a readjustment of the distribution device, wherein, within the scope of the readjustment of the distribution device, the direction of rotation of the distribution device about the vertical axis and the conveying direction of the distribution device are determined taking into account the actual and the target position in such a way that the required angle of rotation about the vertical axis is minimal.

[0019] The next emptying process can then be started, taking into account the positioning time of the distribution device or the rotary distribution belt.

[0020] The invention further relates to a concrete mixing plant with a multi-chamber silo and a feeding device according to the invention. The mixing plant typically further comprises a mixer for mixing aggregates stored in the silo with cement, which can be stored in a separate silo or container of the mixing plant, and water to form concrete. The fresh concrete thus produced can then be delivered to a truck mixer via a discharge device of the mixing plant.

[0021] Further details and advantages of the invention will become apparent from the exemplary embodiment described below with reference to the figures. The figures show: Figure 1: a side view of a concrete mixing plant according to the invention; and Figure 2: a top view of this concrete mixing plant.

[0022] The concrete mixing plant of the present invention comprises two separate feed hoppers 1 and 2 for feeding aggregate, each of whose outlets is coupled to a transfer device 3 designed as a vibrating chute. The vibrating chutes 3 can be controlled independently of one another and serve to uniformly fill the vertical bucket elevator 6 via a belt conveyor 4, which ends at the inlet 7 of the bucket elevator 6.

[0023] An outlet 8 of the bucket elevator 6 is followed by a conveyor 9 designed as a branch belt and a distribution device 10 designed as a rotary distribution belt to transport the aggregate into one of the chambers 12 of the multi-chamber aggregate silo 11. Each chamber 12 contains a continuous level indicator 13.

[0024] Instead of the arrangement of belt conveyor 4, bucket elevator 6 and stub belt 9, other conveying devices can also be provided, for example a single belt conveyor or an S-conveyor.

[0025] Above the belt conveyor 4 are two material detectors 5 designed as material sensors, each of which is coupled to one of the feed hoppers 1 or 2. During operation, the material sensors 5 signal to a control unit (not shown) when a feed hopper 1 or 2 is completely empty in order to mark the start of a necessary follow-up time in the event of a material change. When determining the follow-up time, the control unit takes into account the time required for material transport of the aggregate from the vibrating chute 3 via the belt conveyor 4, the bucket elevator 6, the branch conveyor 9 and the rotary distribution belt 10 into the silo chamber 12 of the aggregate silo 11. By appropriately positioning the material sensors 5 depending on the conveyor belt speed and the conveying distance, the follow-up time can be optimally shortened.

[0026] In order to minimize the pivoting times required on average for the rotary distribution belt 10 when positioning it to another silo chamber 12, a rotary distribution belt is used that is reversible with respect to the (horizontal) conveying direction of the belt and that can be rotated in both directions (clockwise and counterclockwise) about a vertical axis.

[0027] Silo chamber 12 is selected via position switches. By scanning the delivery note (e.g., QR code), errors in chamber selection can be prevented.

[0028] The silo 11 of this concrete mixing plant can be fed as follows.

[0029] A truck driver drives to the facility and either manually selects silo chamber 12 (e.g., chamber 1) using a control system, or a delivery note is automatically scanned, e.g., using a QR code. The scanned information contains details about the quantity of aggregate and the type of rock. From this, the facility's control system determines the correct silo chamber 12.

[0030] The system's control system then checks, based on the delivery data or manual input, whether the chamber's capacity is sufficient for the delivery quantity. It receives the corresponding information on the current fill level from fill indicator 13. Optionally, a visual check can also be performed using a suitable display, such as an LED.

[0031] If, in an example scenario, the feed hopper 1 has just been filled and is currently being emptied, the truck driver must now unload his load into the feed hopper 2.

[0032] As soon as the feed hopper 1 signals that it is empty, which is done via the material sensor assigned to this feed hopper, a follow-up time is waited for before the rotary distributor belt 10 is repositioned. During the follow-up time, the emptying of the feed hopper 2 can already begin.

[0033] To reposition the rotary distributor belt 10, the control system detects the fastest possible position change to move the rotary distributor belt 10 from an actual to a target position for feeding the new silo chamber 12. The direction of rotation of the rotary distributor belt 10 around a vertical axis (clockwise or counterclockwise) and the new conveying direction of the rotary distributor belt are then determined. The rotary distributor belt is repositioned accordingly.

[0034] While the feed hopper 2 is being emptied, the feed hopper 1 can be refilled at the same time to start a new cycle.

Claims

1. Filling device for a concrete mixing plant having a feed hopper (1, 2) for an aggregate and a multi-part transport system for conveying the aggregate from an outlet of the feed hopper (1, 2) to an inlet of a multi-chamber silo (11), wherein the multi-part transport system comprises an initial transport device, a central transport device and a final transport device in a staggered arrangement, wherein the filling device has at least two feed hoppers (1, 2) and the initial transport device is designed to convey aggregate from the outlets of the at least two feed hoppers (1, 2) in the direction of the central transport device; wherein the filling device has a material detector (5) in the area of the initial transport device for recognising complete emptying of the at least two feed hoppers (1, 2); wherein the initial transport device has a belt conveyor (4), wherein the initial transport device has at least two transfer devices (3), and wherein the material detector (5) is arranged on the belt conveyor (4) in the area of the at least two transfer devices (3), in particular in the conveying direction directly after the at least two transfer devices; characterised in that the final transport device has a distribution device (10) that can be rotated clockwise and anti-clockwise about a vertical axis and can be reversed; and in that the filling device has a control unit designed to recognise a complete emptying of a feed hopper (1, 2) by means of a signal from the material sensor (5), to determine a run-on time, and to initiate a readjustment of the distribution device after the run-on time has elapsed, wherein the direction of rotation of the distribution device (10) about the vertical axis and the conveying direction of the distribution device (10) are determined as part of the readjustment of the distribution device (10), taking into account the actual position and the target position, such that the required angle of rotation about the vertical axis is minimised.

2. Filling device according to claim 1, characterised in that the at least two transfer devices are in particular vibrating chutes (3) for conveying aggregate from the outlets of the at least two feed hoppers (1, 2) onto belt conveyors (4), wherein it is provided that the transfer devices (3) can be controlled individually.

3. Filling device according to either one of the preceding claims, characterised in that at least two individual material detectors (5) are provided, wherein each of the material detectors (5) is assigned to one of the feed hoppers (1, 2).

4. Filling device according to any one of the preceding claims, characterised in that the final transport device has conveying means, in particular a branch conveyor belt (9) to convey aggregate from the central transport device to the distribution device (10).

5. Filling device according to any one of the preceding claims, characterised in that the sections of the distribution device (10), which extend in opposite directions starting from the area through which its vertical axis of rotation runs, are of equal length.

6. Filling device according to any one of the preceding claims, characterised in that the filling device has a reading device for automatically reading in information on an aggregate to be fed into the feed hopper (1, 2).

7. Concrete mixing plant having a multi-chamber silo and a filling device according to any one of the preceding claims.