Device and method for cooling aggregate for the production of fresh concrete

Abstract

The invention relates to a device (1) for cooling aggregate for the production of fresh concrete, comprising a cooling drum (2) which is designed to continuously convey cooling water (16) and aggregate in countercurrent with mutual contact. The cooling drum (2) has a cylindrical housing (4) and a shaftless screw conveyor (5) arranged therein for conjoint rotation; the shaftless screw conveyor (5) has a conveying screw (14) and shovel-like blades (22) arranged thereon; and the cooling drum (2) has, in the longitudinal direction of the housing (4), an inlet for aggregate and an outlet (7) for cooling water (16) at one end and an outlet for aggregate and an inlet (6) for cooling water (16) at the other end. The invention also relates to a system comprising a device (1) of this type and a silo (29) for storing cooled aggregate.

Description

[0001] Device and method for cooling an aggregate

[0002] The invention relates to a device for cooling aggregate for the production of fresh concrete, comprising a cooling drum configured to continuously convey cooling water and aggregate in countercurrent flow with mutual contact. The invention further relates to a system for providing cooled aggregate for the production of fresh concrete and a method for cooling aggregate for the production of fresh concrete.

[0003] To ensure that a concrete structure possesses the desired properties, the processing of fresh concrete must take place at predetermined temperatures or within specified temperature ranges. Typically, proper processing of fresh concrete requires that the concrete be at a temperature below 28°C, below 25°C, and possibly even below 20°C or 18°C, depending on the structure. Adherence to the specified temperatures during processing is of paramount importance, especially for large concrete structures such as dams, because otherwise the finished structure will not reliably meet the required properties regarding durability and load-bearing capacity.

[0004] Fresh concrete consists essentially of the following components: cement and water, as well as aggregates, which include in particular sand and rock. Furthermore, admixtures are used, which are primarily intended to influence the plasticity and deformability of the fresh concrete as desired.

[0005] Fresh concrete is generally defined as concrete that has not yet hardened. The cement paste, the mixture of water, cement, and other fine-grained components, has not yet set. This means that fresh concrete is still workable, i.e., malleable and partially flowable. While the cement paste is setting, the concrete is referred to as young concrete or green concrete. Once the cement paste has set, the concrete is called hardened concrete.

[0006] To achieve the desired target temperature of the fresh concrete, it is not possible to cool the fresh concrete mix made from the individual components. Instead, cooling must take place during production and / or one of the components must be pre-cooled.

[0007] It is known from the prior art that the water used in fresh concrete production can be pre-cooled or partially replaced with ice. Partial replacement of water with ice, in particular, achieves good cooling effects. However, the use of energy-intensive ice cooling systems is a disadvantage. Furthermore, even with the use of ice, the desired target temperature cannot always be reached because the percentage of water by mass is relatively small compared to the other components of the fresh concrete mix.

[0008] It is also known from the prior art to pre-cool the water used for fresh concrete production by means of an ice machine. For example, DE 20 2009 005 112 U1 and WO 2011 / 020449 A1 each disclose a generic device, i.e., a device for cooling aggregate for the production of fresh concrete, with a cooling drum configured to continuously convey cooling water and aggregate in countercurrent flow with mutual contact, wherein the cooling water is supplied to an ice machine before entering the cooling drum. A disadvantage here, too, is the high energy consumption caused by the ice machine.

[0009] Furthermore, WO 2014 / 086404 A1 discloses a device for cooling goods in a drum using chilled water. A continuous screw conveyor with many spiral turns is mounted on the inner wall of the drum, forcing the goods to be cooled in the opposite direction to the flow of the water. Between each pair of spiral turns, a chamber is provided, which has an opening in a section near the wall. The openings in adjacent spiral turns are arranged with a defined angular offset from each other, so that the water flow occurs only between adjacent chambers of the drum.

[0010] Instead of cooling the aggregate, pre-cooling the cement and / or sand is technically conceivable, but only very cumbersome and therefore expensive to implement and also not very effective, since both sand and cement are used in only a relatively small proportion in relation to the total quantity.

[0011] The aggregate accounts for by far the largest mass in relation to the final total weight. Therefore, by appropriately cooling the aggregate, the desired target temperature of the fresh concrete can be achieved simply based on its mass. It is thus preferable to cool the aggregate using water.

[0012] In this context, so-called irrigation systems have also become known, which are used to sprinkle rock transported on a conveyor belt with water. Such systems are very complex and, in particular, too expensive for transportable concrete mixing plants. Furthermore, they require a lot of space.

[0013] Irrigation of stockpiles is also known from the prior art. This method utilizes the evaporative cooling effect of the water. However, in normal operation, rock is removed from a stockpile using a wheel loader, so uniform saturation and utilization of evaporative cooling are not possible. Since it is crucial for the desired fresh concrete quality that both the mix design and the target temperature are precisely maintained, water irrigation of rock on stockpiles is technically very complex and therefore costly, especially with regard to achieving the desired mix.

[0014] There is therefore a vital industrial interest in reducing the construction effort in plant engineering and the energy required in the production of fresh concrete.

[0015] The invention is therefore based on the objective of providing a device with which the cooling of fresh concrete can be achieved in an energy-efficient manner and with comparatively little effort.

[0016] To solve this problem, the invention proposes a device of the type mentioned above, characterized in that the cooling drum has a cylindrical housing and a spiral conveyor arranged therein in a twisted manner, the spiral conveyor having a conveying helix and paddle plates arranged thereon, and that the cooling drum has, in the longitudinal direction of the housing, an inlet for aggregate and an outlet for cooling water at one end and an outlet for aggregate and an inlet for cooling water at the other end. Preferably, the inlet for the aggregate corresponds to the outlet for the cooling water, and the outlet for the aggregate corresponds to the inlet for the cooling water.

[0017] Furthermore, to solve this problem, a system for providing cooled aggregate for the production of fresh concrete is proposed, comprising a device of the type according to the invention and a silo for storing aggregate cooled by means of a device according to the invention.

[0018] Furthermore, to solve this problem, a method for cooling an aggregate for the production of fresh concrete is proposed, in which the aggregate and cooling water are continuously conveyed in countercurrent flow and brought into contact with each other by means of a device according to the invention.

[0019] The cooling process according to the invention, using the device according to the invention, has several advantages. Firstly, it enables effective cooling. Tests have shown that the aggregate leaves the cooling drum at a temperature approximately 3°C above the inlet temperature of the cooling water. Therefore, when cooling is carried out with water at 12°C, the aggregate leaves the cooling drum at a temperature of approximately 15°C.

[0020] It has also been shown that such a temperature is sufficient for the aggregate to achieve the desired target temperature of the finished concrete mix. This is, of course, contingent on the aggregate being processed promptly after cooling by the cooling drum, or on the use of a system according to the invention that allows for the intermediate storage of cooled aggregate. The entire process is very energy-efficient, as it does not require the use of ice or water cooled to a very low temperature, for example, by an ice machine, for cooling the aggregate.

[0021] Since the cooling rate or cooling using the device according to the invention is very effective and the cooled rock only needs to be about 3°C ​​warmer than the water used for cooling, it is perfectly sufficient to use cooling water at a low double-digit Celsius temperature, particularly between 10°C and 15°C. A further advantage is that the device according to the invention is very simple and robust in its construction. The supply of cooling water or of the aggregate to be cooled is also technically relatively straightforward.

[0022] From a process perspective, it is therefore preferred that the temperature of the cooling water is set to a predeterminable cooling temperature before contacting the aggregate, which is a maximum of 5 °C, preferably a maximum of 4 °C, and in particular a maximum of 3 °C, below the predeterminable target temperature of the aggregate after contacting has been completed.

[0023] The device according to the invention enables a very efficient process. In particular, compared to cooling with ice, it allows for very energy-efficient processing. Thus, the process according to the invention allows for savings of 30 to 50% in primary energy compared to cooling with ice. This also has the advantage that a machine for ice production can be completely dispensed with, which is also economically advantageous.

[0024] The primary energy savings achieved through this process result primarily from the fact that, to achieve the desired fresh concrete temperature, it is sufficient to use water at a temperature of, for example, 15°C to cool the aggregate. With such a cooling water temperature, the aggregate temperature in the intended process is approximately 18°C.

[0025] To achieve a cooling water temperature of, for example, 15°C, it is cooled in a plate heat exchanger in a counterflow with fresh water. The fresh water, taking into account a temperature variation of 3°C, has a temperature of 12°C. To maintain such a fresh water temperature, an evaporation temperature of approximately 9°C is required.

[0026] In contrast, ice production in conventional ice generators operates at an evaporation temperature of approximately -10°C to -25°C. The process achievable with the device according to the invention thus allows for a significantly higher evaporation temperature compared to the prior art, resulting in primary energy savings of up to 50%. Nevertheless, when the process according to the invention is carried out as intended, it is ensured that the desired target temperature of the fresh concrete can be achieved reproducibly.

[0027] The device according to the invention, and the method achievable with it, offer further advantages: Contact with the cooling water results in complete saturation of the aggregate with water. The cooled aggregate thus has a defined water content. This is of particular importance for maintaining the concrete mix design. The amount of water to be added from the aggregate to the concrete mix can be reduced by the defined amount of water contained in the saturated and cooled aggregate. In this context, it is also advantageous that the amount of aggregate can be reduced compared to the amount that would be required with dry aggregate. It has been shown that this can result in savings of approximately 15% to 20% in admixtures.This means a particularly advantageous saving that roughly corresponds to the investment costs for a device according to the invention.

[0028] According to the invention, a cooling drum with a spiral conveyor is used for cooling the rock. This cooling drum is preferably horizontally oriented and is supplied with the aggregate to be cooled on one side and with cooling water on the other. Due to an internal spiral helix, also called a conveying helix, of the spiral conveyor, the warm aggregate is transported from the inlet to the outlet. The cooling water, introduced in the opposite direction, cools the aggregate during transport from the inlet to the outlet.

[0029] The spiral conveyor also features paddle plates. These paddle plates are arranged on the spiral or conveying helix. The resulting design consists of a cooling drum with a cylindrical housing and a spiral conveyor twisted inside it, the spiral conveyor comprising a conveying helix and paddle plates attached to it.

[0030] The paddle plates have the advantage of ensuring intensive mixing of the aggregate and cooling water, thus maximizing heat transfer from the aggregate to the cooling water. Without paddle plates, there is a risk that the aggregate fed into the spiral conveyor will pass through it in "packets" without thorough and complete mixing with the cooling water. Under normal operating conditions, the spiral conveyor ensures that the aggregate fed into the spiral conveyor is transported lengthwise along the spiral until it reaches the outlet of the cooling drum.During transport, the paddle blades ensure that the aggregate bundles located between the individual spirals of the conveyor helix are carried along the circumference of the helix and, upon reaching a certain vertical speed, fall off the corresponding paddle blade. This advantageously results in complete immersion of the individual aggregate components with cooling water, thus optimizing the cooling effect. A turbulent flow is created around the aggregate components, drastically increasing the heat transfer coefficient.

[0031] According to a further feature of the invention, each 360° helix is ​​provided with two paddle plates arranged circumferentially offset from one another. The conveying helix can have a plurality of individual 360° helixes. For example, six, eight, or even more such helixes can be provided. These helixes are arranged one behind the other in the longitudinal direction of the conveying helix.

[0032] Each 360° helix preferably has two paddle blades. These are arranged at an angle to each other, for example, offset by 180°. This ensures thorough mixing of the aggregate conveyed by each 360° helix.

[0033] According to a further feature of the invention, the spiral conveyor is provided to have a total of twelve paddle plates. It has been shown that such a number of paddle plates is sufficient to ensure the desired complete mixing of the aggregate and cooling water.

[0034] According to a further feature of the invention, an angular offset of 20° to 25°, preferably 22.5°, is formed in the circumferential direction between two paddle plates arranged successively in the longitudinal direction of the conveyor helix. Thus, the paddle plates are not arranged in a straight line one behind the other in the longitudinal direction, but rather at an angle to each other from helix to helix. This additionally ensures that individual aggregate packages are not unintentionally conveyed through the conveyor helix in the longitudinal direction without being completely mixed with cooling water.

[0035] According to a further feature of the invention, a paddle plate has rectangularly shaped large surfaces that extend longitudinally and radially along the conveying helix. The surface normal of a large surface is thus orthogonal to the radial direction of the conveying helix, so that maximum mixing of the aggregate conveyed by the helix can take place through the paddle plates. This further optimizes the mixing of aggregate and cooling water with the aim of achieving the most effective possible cooling of the aggregate.

[0036] According to a further feature of the invention, the conveying helix has radially extending slots on its inner circumference. These slots also ensure improved mixing of the aggregate and cooling material, since the slots are permeable to cooling water while retaining the aggregate. In this way, an additional cross-flow between the cooling water and the aggregate can be achieved.

[0037] According to a further feature of the invention, the spiral conveyor has disc-shaped end plates between which the conveying helix is ​​arranged.

[0038] The disc-shaped end plates define the boundaries of the conveying helix. Under normal operating conditions, the aggregate or cooling water conveyed by the helix cannot be transported beyond its length, as the end plates at the ends of the helix act as a barrier. Mass flow is only possible through the openings provided by the end plates, as will be described in more detail below.

[0039] The design of the spiral conveyor and end plates also offers the advantage of simplified manufacturing, as it is sufficient to attach the end plates to the ends of the spiral conveyor, for example by welding, to provide the finished product. This results in an overall robust and therefore durable construction.

[0040] According to a further feature of the invention, the end plates are circular. This allows for a largely gap-free arrangement of the spiral conveyor within the associated housing, which is preferably cylindrical in shape to correspond to the circular end plates. This advantageously prevents unwanted mass flow past the end plates.

[0041] According to a further feature of the invention, it is provided that the end plates each have a through-opening, wherein the through-openings are aligned with each other centrally to the axis of rotation of the conveyor helix.

[0042] In its intended use, the spiral conveyor is fed with aggregate and / or cooling water through the corresponding openings in the end plates. One opening serves as an inlet for the cooling water and simultaneously as an outlet for the aggregate. The other opening serves as both an inlet for the aggregate and an outlet for the cooling water. Therefore, in normal operation, cooling water is fed into the spiral conveyor at one end, while aggregate is fed into the other. As a result, the cooling drum is fed with cooling water and aggregate in a counter-current flow, as previously described.

[0043] According to a further feature of the invention, the through-openings are of different sizes. This takes particular account of the fact that different mass flows must be supplied to the spiral conveyor, namely aggregate on the one hand and cooling water on the other.

[0044] In this context, it is preferred that the smaller opening serves as an outlet for the aggregate on the one hand and an inlet for cooling water on the other. This ensures that the cooling water fed into the screw conveyor is conveyed as intended along the length of the screw conveyor, without the risk of cooling water unintentionally flowing back through the inlet. The differently sized openings thus ensure, particularly with regard to the cooling water, that the intended inlet and outlet of cooling water can occur.

[0045] According to a further feature of the invention, the spiral helix, i.e., the conveying helix, is connected to an inner wall of the housing in a rotary motion-coupled manner at least at one end in the longitudinal direction and / or on the outer circumference in the radial direction. A spiral conveyor, as defined by the invention, is a modification of a screw conveyor in which a central axial drive shaft is omitted. The drive of the spiral conveyor is therefore preferably achieved via a corresponding coupling with the housing. The housing, in turn, preferably has a drive shaft which is connected to a corresponding drive provided by the device, in particular a motor, preferably an electric motor.

[0046] According to a further feature of the invention, the housing and spiral helix are arranged coaxially with respect to their respective axes of rotation and are horizontally aligned with respect to the vertical direction. "Load direction" in the context of the invention refers to the local direction of the acceleration due to gravity. This advantageously ensures uniform contact between the aggregate and the cooling water. A flow gradient within the cooling drum is therefore avoided.

[0047] Preferably, the inlet for the cooling water is smaller than its outlet. This ensures that the cooling water can only flow through the cooling drum from the cooling water inlet to the cooling water outlet. In particular, it is provided that the inlet and outlet for the cooling water are each designed as a circular hole, which are arranged coaxially with respect to the axis of rotation of the housing, with the radial extent of the cooling water outlet being larger than the radial extent of the cooling water inlet. The process preferably involves setting a cooling water level within the cooling drum that lies radially above the cooling water outlet but below the cooling water inlet.

[0048] According to a further feature of the invention, the spiral helix has radially extending recesses, in particular slots and / or holes, on its inner circumference, with the recesses extending axially through the spiral helix. This improves the flow characteristics of the cooling water within the cooling drum. In this respect, it is particularly advantageous if immediately adjacent recesses are arranged equidistantly from one another in the direction of the helix and if the recesses are evenly distributed over the entire spiral helix.

[0049] According to a further feature of the invention, the spiral conveyor and / or the housing has a length of 8 m to 12 m and a diameter of 1.5 m to 2.3 m. This provides a conveying distance at the end of which the target temperature of the aggregate is reliably reached. From a process perspective, it is preferred that the aggregate and cooling water are in contact with each other in counterflow over a conveying distance of 8 to 12 meters. Furthermore, this makes it possible to arrange the entire device, in particular the cooling drum, and preferably the cooling circuit, within a conventional 40' container (shipping container), which greatly simplifies transport. Moreover, the container with the device can be positioned directly, i.e., in the immediate vicinity of a mixing hopper, so that the cooled aggregate can be processed immediately after leaving the cooling drum.

[0050] According to a further feature of the invention, a cooling water circuit is provided, which fluidically connects the cooling water outlet of the cooling drum with the cooling water inlet of the cooling drum. Preferably, the cooling water circuit includes a settling tank for separating rock particles originating from the aggregate. The heated cooling water leaving the cooling drum is first directed into the settling tank. Here, suspended particles can settle to the bottom, primarily due to gravity. Alternatively or additionally, it is preferably provided that the settling tank includes a particle filter, particularly in the form of a geotextile. The particle filter preferably has a diameter of 1.1 to 1.3 m and a height of 1.7 to 2.1 m. Such a settling tank, also called a settling basin, is purely optional and is therefore only provided if required.

[0051] In terms of the process, it is preferred that the cooling water is circulated, whereby heated cooling water is first cleaned of components of the aggregate after contact with the aggregate.

[0052] Preferably, the cooling water circuit further comprises a heat exchanger, in particular a plate heat exchanger, located downstream of the slurry tank in the direction of flow of the cooling water, for cooling and adjusting the temperature of the cooling water to a predetermined cooling temperature. The heat exchanger, in particular the plate heat exchanger, is preferably operated in counterflow with a cooling medium in the form of fresh water, which is preferably circulated in a second cooling circuit.

[0053] It is particularly preferred that the cooling water circuit has a control unit which has at least one sensor for measuring an actual value of the cooling water temperature, which is arranged in the flow path of the cooling water and upstream of the heat exchanger, and which has a data processing unit which is configured to compare the sensor-measured actual value with a target cooling temperature stored in the data and is configured, in the event of a predefinable deviation of the actual value from the target cooling temperature, to control the heat exchanger to which it is connected in such a way that the actual value is adjusted to the target cooling temperature within a predefinable tolerance.

[0054] The process preferably involves adjusting the purified cooling water to the desired cooling temperature after it passes through the evaporation tank. It is particularly preferred that the purified cooling water is passed through a heat exchanger to achieve this temperature adjustment, using fresh water as the cooling medium. Furthermore, it is preferred that the cooling temperature is adjusted by continuously comparing a continuously sensor-monitored actual value with a stored target value, where the target value is defined by a specific cooling water temperature. If the actual value deviates from the target value, the heat exchanger is activated by the control system to correct this deviation.

[0055] According to a further feature of the invention, a first conveying means, in particular a first conveyor belt, is provided, which serves for the continuous transport of the aggregate to be cooled to the cooling drum. The first conveying means is arranged in the conveying direction of the aggregate upstream of the cooling drum. This simplifies the process through automation.

[0056] Furthermore, a second conveying element, in particular a second conveyor belt, is preferably provided, which serves for the continuous transport of the cooled aggregate and preferably for the conveying connection to a mixing hopper for mixing fresh concrete. The second conveying element is located downstream of the cooling drum in the conveying direction of the aggregate. This simplifies the process through further automation. According to a particularly preferred feature of the invention, the second conveying element has a thermally insulated housing. This ensures, particularly in regions of the world with intense solar radiation, that the cooled aggregate is maintained at the target temperature on its way to further processing.

[0057] The process preferably involves transporting the cooled aggregate directly to a mixing bunker where fresh concrete is produced. Preferably, the cooled aggregate is mixed with water and cement.

[0058] The use of a slurry tank, as described above, is purely optional. A slurry tank is particularly useful when cooling the cooling water with fresh water is carried out using plate heat exchangers. The use of a slurry tank is preferred in this case because it prevents the plate heat exchangers from becoming clogged by rock particles, debris, and / or other impurities carried in the cooling water. Therefore, the use of a slurry tank is preferred when subsequent cooling of the cooling water is carried out using plate heat exchangers.

[0059] According to an alternative and preferred embodiment of the invention, a heat exchanger unit, which is not a plate heat exchanger, is used to cool the cooling water. Such a heat exchanger unit is preferably designed as an open heat exchanger. It is particularly preferred to form the open heat exchanger from individual vats connected in series in terms of flow characteristics. Such a vat is formed by a container, preferably a container with a cylindrical shape. The containers are designed without lids, i.e., they are open at the top. Therefore, such a heat exchanger unit is also an open heat exchanger.

[0060] At least two vats of the type described above are provided, but preferably three, four, or even more vats. In the simplest case, particularly for cost reasons, only one vat may be provided. The essential aspect of the invention is solely that the heat exchanger unit achieves such cooling that the cooled water can subsequently be used as intended.

[0061] The cooling water exiting the cooling drum at the water outlet is pumped via a flow-through connection into the first vessel of the open heat exchanger. From there, the cooling water flows from vessel to vessel until it reaches the last vessel of the heat exchanger. From there, the cooled water is returned to the cooling drum. The last vessel of the heat exchanger is thus fluidically connected to the cooling water inlet of the cooling drum. With appropriate sizing, the open heat exchanger can also have only one vessel. Compared to a heat exchanger with several vessels connected in series, this results in cost reductions and simplified operation.

[0062] To cool the cooling water using appropriately tempered fresh water, plates are used in the intended application, through which the fresh water flows. These plates are immersed in the individual vats. Three, four, five, or even more individual plates can be provided per vat. These plates are connected to an inlet manifold on one side and an outlet manifold on the other. In the intended application, appropriately tempered fresh water is supplied through the inlet manifold. From there, the individual plates connected to it are flooded with fresh water, or rather, the fresh water flows through the plates connected to it. These plates are immersed in the individual vats of the heat exchanger, so that the cooling water contained within is cooled, as it is in direct contact with the individual plates.Under normal operating conditions, the cooling plates arranged in the vats are circulated by the cooling water contained in the vats. In an alternative design, refrigerant can circulate through the individual plates instead of fresh water. In this case, an additional refrigeration system is provided in combination with the heat exchanger unit to cool the refrigerant after it has passed through the heat exchanger unit.

[0063] On the flow outlet side, the individual plates are connected to the outlet manifold, so that the fresh water heated after heat transfer can be discharged via this manifold.

[0064] The use of the aforementioned open heat exchanger has the particular advantage that the rock particles, impurities, and / or other contaminants carried along by the cooling water cannot lead to a blockage of the heat exchanger, as is the case with the use of a plate heat exchanger. Therefore, the use of a floatation tank can be advantageously dispensed with.

[0065] To prevent rock particles, contaminants, and / or other impurities carried by the cooling water from washing out the aggregate, it is further proposed that each tub be equipped with an agitator. Such an agitator ensures that the cooling water in a tub is constantly stirred and thus continuously circulated, keeping any rock particles, contaminants, and / or other impurities in motion and suspended, thereby ensuring their return to the aggregate. This advantageously allows for adherence to the mix design for the fresh concrete to be produced.

[0066] A further advantage of the open heat exchanger is that, lacking a required slurry tank, it can be compactly housed in its own enclosure. In particular, it is possible to house the open heat exchanger in a container, preferably a standard 40-foot container. Since the aforementioned cooling drum can also be housed in such a container, the result is a compact overall design consisting of two individual containers that can be stacked on top of each other. This advantageously allows for easy transport and simple on-site assembly. The container with the cooling drum is preferably positioned at the bottom, and the container housing the open heat exchanger is positioned above it, resting on the container containing the cooling drum. The system configured in this way is ready for operation without any further construction work.All that's needed is a fresh water supply and an electrical connection.

[0067] According to a further feature of the invention, the aggregate is dewatered after passing through the cooling drum as intended. "Dewatered" in the context of the invention means that cooling water adhering to the surface of the aggregate is removed. This is advantageous for two reasons. Firstly, it prevents unwanted carryover of cooling water. Secondly – ​​and this is a significant advantage – it ensures adherence to the recipe for the subsequent fresh concrete mix. The latter also has the further advantage that the aggregate exiting the cooling drum can be directly processed further, for example, in a concrete mixing plant.

[0068] If the aggregate is not dewatered as described above, the cooling water carried along with the aggregate will drip off. If the aggregate is temporarily stored in a silo, this dripping water collects at the bottom of the silo. If a concrete mixing plant is then fed from this silo, the batch near the bottom of the silo will be particularly moist due to the accumulated dripping water, or the last batch of aggregate will contain a higher water content compared to the other batches. This can lead to unintended inconsistencies in the mix design. The aggregate dewatering process provided according to the invention, which takes place after the aggregate has passed through the cooling drum, eliminates this disadvantage.

[0069] A dewatering screen is preferably used to dewater the aggregate. This dewatering screen is designed like a circulating conveyor belt and has corresponding openings through which dripping water can pass and then be conveyed away. The dripping water is preferably collected in a suitable trough so that it can be gathered and then returned to the cooling water circuit, thus enabling virtually loss-free operation of the cooling water circuit.

[0070] As a result, the aforementioned alternative of the inventive design is preferred, since a floatation tank can be dispensed with and, synergistically, a compact overall design of the entire system is made possible, as the cooling drum on the one hand and the heat exchanger on the other can each be housed in a single container. Furthermore, adherence to the recipe can be maintained, as unwanted carryover of aggregate particles is avoided.

[0071] In combination with both the first and second alternatives of the invention, drying of the aggregate is provided after it has passed through the cooling drum as intended. Preferably, a dewatering screen, designed as a conveyor belt, serves for drying. This screen is connected to the cooling drum on the aggregate outlet side. It allows residual cooling water adhering to the surfaces of the individual aggregate particles to drip off and then be removed. Unwanted carryover of cooling water is thus avoided, and in this context, it is particularly advantageous that reproducible and controllable consistency with regard to the composition of the fresh concrete is maintained.

[0072] The invention further proposes a system for providing cooled aggregate for the production of fresh concrete, comprising a device of the type according to the invention and a silo for storing cooled aggregate.

[0073] The system according to the invention comprises a device according to the invention for cooling aggregate and a silo for storing the aggregate previously cooled by the device. This storage enables a concrete mixing plant to be continuously supplied with cooled aggregate for the production of fresh concrete. The underlying concept of both the system according to the invention and the device according to the invention is to provide the aggregate required for fresh concrete production in a quantity and temperature sufficient for continuous production, even for large-scale applications. The aggregate provided and cooled according to the device according to the invention is ready for processing into fresh concrete. However, due to its design, the device has a limited throughput.When producing a relatively large quantity of fresh concrete, the device according to the invention must therefore be operated with a corresponding lead time so that ready-to-use aggregate is pre-produced before the actual fresh concrete production begins. This carries the risk that the pre-produced aggregate will reheat uncontrollably, which must be avoided at all costs. Either the aggregate leaving the device is processed immediately, or it is temporarily stored in a silo of a system according to the invention.

[0074] To prevent the cooled aggregate stored in the silo from warming up again, it is planned to keep the aggregate cool during storage in the silo. Alternatively, it would be possible to cool the silo itself instead of the aggregate. However, silo cooling has not proven effective and is also complex to implement. The system according to the invention therefore proposes to keep the aggregate, which has been previously cooled and then transferred to the silo, cool while it is inside the silo. This ensures the reliable provision of cooled aggregate for fresh concrete preparation.

[0075] According to a further feature of the invention, the silo is provided to have a storage bunker for chilled aggregate, as well as an inlet for cooling water and aggregate and an outlet for cooling water and aggregate. The silo provides a storage bunker. In its intended use, this bunker serves to store chilled aggregate. For this purpose, an inlet is provided through which the storage bunker can be filled with aggregate. Furthermore, an outlet for aggregate is provided so that, in its intended use, chilled aggregate can be withdrawn for the preparation of fresh concrete.

[0076] Furthermore, an inlet and an outlet for cooling water are provided. This allows the storage bunker to be filled with cooling water so that the aggregate contained therein can be cooled, or at least the temperature of the previously cooled aggregate can be maintained, thus preventing the aggregate from heating up during storage in the silo.

[0077] According to a further feature of the invention, a separation device is provided which is operatively connected to the outlet and is designed to separate cooling water from cooled aggregate.

[0078] In its intended use, the silo's storage bunker contains aggregate on one side and cooling water on the other. At the silo's outlet, the cooling water and aggregate must be separated so that, for fresh concrete preparation, cooled aggregate is available in the exact quantity required by the recipe – meaning it is not diluted with residual cooling water. The system according to the invention therefore provides a separation device at the silo's outlet. This separation device is designed to separate the cooling water from the cooled aggregate, ensuring that the cooled aggregate is available in the exact quantity required by the recipe.

[0079] According to a further feature of the invention, the separation device is designed in multiple stages. In particular, a two-stage separation device is provided so that the desired consistency of the recipe can be reliably maintained. Due to the at least two-stage design, it is especially ensured that excess cooling water is drained off before the cooled aggregate is used further.

[0080] According to a further feature of the invention, the separation device comprises two cone-shaped pipe sections arranged one after the other in the direction of flow of the cooling water and the aggregate. Preferably, according to a first stage, the separation device has two pipe sections. In the event of discharge, both cooling water and aggregate are conveyed through these two pipe sections. The pipe sections are tapered, thus narrowing in the direction of flow. This creates a kind of funnel effect, which allows for the targeted discharge or removal of cooling water and aggregate from the silo.

[0081] In this context, a further feature of the invention provides that the first pipe section in the direction of travel, with its conically tapered end section, projects into the volume space provided by the other pipe section. This creates a kind of cascade of pipe sections. The first pipe section in the direction of travel engages with the second pipe section, and due to the conical shape of the first pipe section, an annular gap forms between the first and second pipe sections. This allows for the targeted discharge of aggregate while simultaneously separating cooling water, as will be explained in more detail below.

[0082] According to a further feature of the invention, the outer surface of the second pipe section in the direction of passage is closed. The second pipe section can thus receive the aggregate carried away via the first pipe section and convey it in a funnel-like manner. The closed outer surface therefore serves as a sliding surface for the carried-away aggregate.

[0083] According to a further feature of the invention, the outer surface of the first pipe section in the direction of flow is designed to be water-permeable. This creates a kind of sieve effect. A mixture of cooling water and aggregate is fed into the first pipe section. Since the first pipe section is designed to be water-permeable, i.e., has a water-permeable outer surface, the cooling water fed into the first pipe section can exit through its outer surface. The aggregate, on the other hand, is retained. This results in an initial separation of the cooling water and the aggregate. The cooling water exiting the first pipe section through its outer surface can be collected and discharged by appropriate devices.The aggregate is conveyed through the first pipe section and then reaches the second pipe section, which conveys the aggregate, largely free of cooling water, onward. According to a further feature of the invention, the second pipe section, with its conically tapered end, interacts with a discharge chute. The aggregate, largely free of cooling water, reaches the second pipe section after passing through the first. This second pipe section interacts with a discharge chute, so that the aggregate fed into the second pipe section is conveyed to the discharge chute, with intermediate sorting. From here, it can then be transported away. The discharge chute thus serves as a dewatering chute with a metering function.

[0084] According to a further feature of the invention, the separation device includes a filter unit which is located downstream of the discharge chute or which is provided by the discharge chute.

[0085] The filter unit of the separation system preferably constitutes the second stage of the separation system. In the filter unit, any residual cooling water, particularly any adhering to the aggregate after passing through the first stage, is removed. This residual amount of cooling water can result, in particular, from a column of water above the outlet of the storage bunker. This column can easily pass through the two aforementioned pipe sections, meaning that the aggregate exiting the first separation stage is still coated with residual cooling water. This residual cooling water is removed in the second separation stage, namely the dedicated filter unit.

[0086] The filter unit can be designed in its simplest form as a grate through which the cooling water can pass, but which retains the aggregate. Such a filter unit can either be a separate component located downstream of the discharge chute, or the discharge chute itself can incorporate the filter unit, in which case the chute itself provides the filter unit. In an alternative design, screen elements arranged in a steel box can serve as the filter unit, with the aggregate being transported by vibratory motors mounted externally on the steel box. In this case, the cooling water flows through openings provided by the screen panels of the screen elements and then collects at the bottom of the steel box. From there, it can be discharged.To minimize the amount of cooling water that can pass through the two pipe sections without collision, a further feature of the invention provides for a conical baffle within the storage bunker, positioned upstream of the cooling water outlet, with the apex of the baffle aligned opposite the cooling water outlet. This design prevents a water column above the outlet from forming, which would otherwise allow the pipe sections of the first separation stage to pass through without collision. Instead, the baffle directs the flow such that the mixture of cooling water and aggregate leaving the storage bunker impacts the preferably perforated outer surface of the first pipe section. This ensures maximized separation of cooling water and aggregate even during the first separation stage.

[0087] According to a particularly preferred feature of the invention, the cooling water is residual water originating from the device of the inventive type. Accordingly, cooling water exiting the cooling drum outlet of the device according to the invention is used to fill the silo. Any entrained rock residues leaving the device according to the invention along with the cooling water are thereby returned to the aggregate stored in the silo, thus pre-loading the cooling water before it is fed into the silo at the inlet. The aggregate in the storage bunker thus acts as a filter, whereby the cooling water flowing through the storage bunker is virtually clear at the outlet of the cooling bunker, i.e., free of any previously contained rock residues.These are retained by the aggregate in the storage bunker, thus being returned to the aggregate, ensuring a particularly optimized adherence to the recipe with regard to the amount of aggregate.

[0088] The result of this further development according to the invention is that the aggregate fed into a silo is continuously cooled and thus kept at temperature. This does not involve silo cooling, but rather the cooling of the already cooled aggregate. This cooling of the aggregate is carried out using process water that exits the cooling drum of the device according to the invention. This offers the advantage that sediments and rock residues carried along by the water are returned to the cooled aggregate in the silo. The use of process water as cooling water thus provides two synergistic advantages. Firstly, the aggregate is cooled, and secondly, any sediments, rock residues, and suspended solids present in the process water are filtered out by the aggregate itself, thereby ensuring maximum consistency with the original recipe.The water exiting the silo is essentially clear water, which is then cooled again but otherwise can be transferred to the inlet of the device according to the invention as cooling water without further treatment. Alternatively, the silo can be filled with cooling water, which is also fed to the cooling drum described above. In this case, cooling water is provided as described above and then serves both to fill the cooling drum and to fill the silo.

[0089] The silo described above with reference to the system according to the invention is patentable in itself. Therefore, the invention also proposes a silo for storing cooled aggregate. Such a silo can have the features and advantages already described above.

[0090] Furthermore, a method for providing cooled aggregate for the production of fresh concrete is eligible for protection in itself, in particular using a system of the type described above, in which an aggregate is cooled by means of cooling water and the cooled aggregate is fed into a silo for storage and in which the cooled aggregate in the silo is further cooled by means of cooling water.

[0091] The process also provides for the use of cooling water, which is taken as wastewater from a previous cooling step, to further cool the aggregate located in the silo.

[0092] Further features and advantages of the invention will become apparent from the following description with reference to the figures. These show:

[0093] Fig. 1 shows a schematic representation of a device according to the invention; Fig. 2 shows a schematic representation of the interior of a cooling drum according to the invention in an axial view;

[0094] Fig. 3 shows a schematic perspective view of a device according to the invention;

[0095] Fig. 4 shows a schematic perspective view of a spiral conveyor according to the invention;

[0096] Fig. 5 shows a schematic perspective view of a silo arrangement of a system according to the invention;

[0097] Fig. 6 shows a schematic sectional view from above of the silo arrangement according to Fig. 5, specifically according to section line BB according to Fig. 7;

[0098] Fig. 7 shows a schematic sectional view from the side of the silo arrangement according to Fig. 6 and

[0099] Fig. 8 shows a schematic sectional view from the side of the silo arrangement according to Fig. 6, specifically according to section line AA according to Fig. 7.

[0100] Figure 1 shows the device 1 according to the invention. The device 1 has a cooling drum 2 and a first cooling circuit 3.

[0101] The cooling drum 2 has a cylindrical housing 4 made of metal, preferably steel, which has a length of 8 m to 12 m, preferably 9 m to 11 m, and a diameter of 1.0 m to 2.5 m, preferably 1.5 m to 2.2 m. The housing 4 has an internal spiral conveyor 5, as shown in detail in Figure 2.

[0102] The housing 4 of the cooling drum 2 has a cooling water inlet 6 at one end and a cooling water outlet 7 at the other end in the axial direction. The cooling water inlet 6 has a smaller cross-section than the cooling water outlet 7. This ensures that the cooling water does not leave the cooling drum 2 via the cooling water inlet 6, but can only flow through the cooling drum 2 from the cooling water inlet 6 to the cooling water outlet 7. The cooling water therefore leaves the cooling drum 2 through the cooling water outlet 7, after passing through the cooling drum 2 in the axial direction, specifically in the conveying direction 8.

[0103] In this case, the cooling water inlet 6 and the cooling water outlet 7 are each designed as a circular opening in the respective end wall of the cylindrical housing 4. The cooling water inlet 6 and the cooling water outlet 7 are each arranged coaxially with respect to the axis of rotation of the housing 4. The radial extent of the cooling water outlet 7 is greater than the radial extent of the cooling water inlet 6. The process preferably involves setting a cooling water level within the cooling drum that lies radially above the cooling water outlet 7 but below the cooling water inlet 6.

[0104] The cooling water flows through the cooling drum 2 in the conveying direction 8. The aggregate to be cooled – also called rock fraction – is conveyed through the cooling drum 2 in the opposite direction 9. The inlet 6 for the cooling water forms the outlet for the aggregate, and the outlet 7 for the cooling water forms the inlet for the aggregate.

[0105] The temperature of the cooling water supplied to the cooling drum 2 at the cooling water inlet can be adjusted as required. The cooling water temperature depends on the desired target temperature of the fresh concrete being produced using cooled aggregate. For example, if a target temperature of 25°C is desired for the fresh concrete, then, assuming the sand, cement, and water temperatures are appropriate, a temperature of 18°C ​​relative to the aggregate is required. Generally, a temperature difference of 3°C is established in cooling drum 2 between the desired aggregate temperature and the cooling water temperature. Therefore, if an aggregate temperature of 18°C ​​is required, cooling water at a temperature of 15°C must be supplied to the cooling drum.

[0106] As will be explained in more detail below, the cooling water is cooled in a second cooling circuit 12 before being fed to the cooling drum 2. The cooling of the cooling water in the second cooling circuit 12 is achieved by means of a heat exchanger, preferably a counterflow plate heat exchanger 11. Such a heat exchanger has a temperature difference of approximately 3°C. Therefore, to reliably achieve an aggregate temperature of 18°C, the cooling water supplied to the cooling drum 2 must be set to 12°C on the plate heat exchanger side. This results in a temperature difference of 6°C between the desired aggregate temperature and the temperature to be set for the cooling water in the second cooling circuit 12.

[0107] Cooling water at a temperature of 12°C can be produced at an evaporation temperature of approximately 9°C. In contrast to prior art cooling methods using ice, this advantageously leads to a saving of approximately 30% to 50% in primary energy consumption at the refrigeration unit, i.e., the compressor. Unlike ice production, an evaporation temperature of -10°C to -25°C is no longer required, but only approximately 9°C, as explained above. The device according to the invention offers the synergistic advantage that, depending on the desired target temperature of the fresh concrete and thus the desired target temperature of the cooled aggregate, higher evaporation temperatures can also be used. This variability depending on the target temperature of the fresh concrete is not possible with ice production.

[0108] The first cooling circuit 3 connects the cooling water outlet 7 to the cooling water inlet 6 via a flow-related system. Cooling circuit 3 is equipped with appropriate pumps and valves (not shown) to generate the flow. Upstream of the cooling drum 2, cooling circuit 3 includes a settling tank 10 for separating rock residues, particularly suspended particles. The settling tank 10 contains a particle filter (not shown), for example, in the form of a geotextile.

[0109] Upstream of the flotation tank 10, the cooling circuit 3 provides a counterflow plate heat exchanger 11 for adjusting the heated cooling water to the cooling temperature. Fresh water is used as the cooling medium and is circulated in a second cooling circuit 12.

[0110] Upstream of the plate heat exchanger 11, a temperature sensor 13 is arranged in the flow path of the cooled cooling water. This sensor is connected to a control unit (not shown), which in turn is connected to the plate heat exchanger 11 and / or flow control elements (not shown), such as pumps and / or valves (not shown). The cooling drum 2 has a drive shaft (not shown) which is connected to a drive unit (not shown) in the form of an electric motor. This causes the housing 4 – and, via rotary coupling, also the spiral conveyor 5 – to rotate about the longitudinal axis of the cylindrical housing 4. The drive unit has a control system that allows the rotational speed of the housing to be regulated.

[0111] As can be seen from an overall view of the diagram in Fig. 1, the cooling water, which cools the aggregate in the intended application, is circulated in the closed cooling circuit 3. The cooling water, set to a preselected cooling temperature, is fed into the cooling drum 2 at the cooling water inlet. It then flows longitudinally through the cooling drum 2, from right to left with respect to the plane of the drawing in Fig. 1, until it reaches the cooling water outlet 7. As it passes through the cooling drum 2, the cooling water heats up due to the cooling of the aggregate. Thus, a heat transfer occurs from the aggregate to the cooling water.

[0112] The heated cooling water exiting cooling drum 2 at the cooling water outlet is then directed to the simmering tank 10. From there, it flows to the plate heat exchanger 11. Here, it is cooled without contact in a counterflow process, either using fresh water or a refrigerant circulating in a separate, closed cooling circuit 12. The cooling water exiting the plate heat exchanger 11 has cooled to the desired temperature, which is monitored by the temperature sensor 13 and, if necessary, adjusted or regulated according to temperature signals. The cooled cooling water is then fed back to cooling drum 2 at the cooling water inlet. From there, it flows back through cooling drum 2 in the direction of flow 8.

[0113] The design of a closed cooling circuit 3 has the particular advantage that any rock particles carried along with the cooled aggregate are continuously circulated, thus preventing any unwanted discharge of rock particles from the aggregate. The quality of the aggregate therefore remains unchanged. If necessary, unwanted rock particles and / or other substances are separated in the settling tank 10, especially those that would impede continuous cooling operation by clogging or blocking individual pipes.

[0114] The closed cooling circuit 3 also offers the advantage of continuous process operation, so that aggregate can be cooled virtually on demand by a concrete plant, and in the quantity required by the plant to produce the fresh concrete to be processed subsequently. The device according to the invention can therefore be operated by a concrete plant on demand as needed. A lead time, such as that required for ice production, for example, is advantageously not required in advance. The device according to the invention is therefore very flexible in its application, both with regard to the operating time or period and with regard to the total quantity of cooled aggregate to be produced.

[0115] Figure 2 shows the interior of the housing 4 of the cooling drum 2. The spiral conveyor 5, the cooling water inlet 6 and the cooling water outlet 7 can be seen.

[0116] The spiral conveyor 5 provides a conveying helix 14, also called a spiral helix, as well as paddle plates 22, which are not visible in the figure. The spiral helix 14 is coupled to the inner wall of the cylindrical housing 4 on its outer circumference and is attached to the inner wall for this purpose.

[0117] Furthermore, the conveying or spiral helix 14 provides radially extending slots 15 on its inner circumference, which extend completely through the conveying or spiral helix 14 in the axial direction. This improves the flow characteristics of the cooling water within the cooling drum 2. To further improve the flow characteristics, adjacent slots 15 are arranged equidistant from each other in the direction of rotation. Additionally, a plurality of slots 15 are evenly distributed over the entire spiral helix 14.

[0118] Also visible is the cooling water 16, which flows through the cooling drum 2 from the cooling water inlet 6 to the cooling water outlet 7 and thereby contacts the unseen aggregate.

[0119] Figure 3 shows the device 1 according to the invention in a schematic perspective view, whereby the paddle plates 22 of the conveying helix 14 are not shown for clarity. These can be seen in particular from the illustration in Figure 4.

[0120] As shown in Figure 3, a feed point 17 serves to supply the cooling drum 2 with aggregate. This feed point is designed in the form of a funnel and is fluidically connected to a conveyor belt and / or similar conveying device. During operation, aggregate can thus be fed into the cooling drum 2 via the feed point 17 through the cooling water outlet 7. The aggregate thus introduced into the cooling drum 2 is then conveyed through the cooling drum 2 in the conveying direction 9 as described above, until it reaches the cooling water inlet 6, through which the cooled aggregate is discharged.

[0121] The spiral conveyor 5 serves to convey the aggregate in the conveying direction 9, and has the conveying or spiral helix 14 equipped with slots 15, which is twisted and received by the housing 4 of the cooling drum 2.

[0122] The cooling water outlet 7 is fluidically connected to a connection nozzle 18. This connection nozzle 18 serves as the fluidic connection to a pipe or line through which the cooling water 16 is guided in a closed flow circuit 3. Cooling water 16, which passes through the cooling drum 2, thus enters the system via the connection nozzle 18, from where it is then transported towards the plate heat exchanger 11 (not shown in Figure 3).

[0123] A drive roller 19 serves to rotate the cooling drum 2; the housing 4 of the cooling drum 2 rests on this roller, transmitting force. The drive roller 19 is driven by a motor, in particular an electric motor.

[0124] Aligned parallel to the drive roller 19, a further roller, not visible in Figure 3, is provided, which as a traveling roller supports the housing 4, which is circular in cross-section, on the rear side with reference to the drawing plane according to Figure 3.

[0125] The entire cooling drum 2 is housed in an enclosure 20. This enclosure 20 can, for example, be a standard 40-foot container. This ensures easy transport of the entire device 1 using conventional means of transport. In particular, transport by ship and / or truck to a desired place of use is easily facilitated.

[0126] Fig. 4 shows a schematic representation of the design of the spiral conveyor 5 according to the invention in detail.

[0127] As illustrated in the exemplary representation of Fig. 4, the spiral conveyor 5 has a conveying helix 14, also called a spiral helix, and paddle plates 22 arranged on the conveying helix 14. These paddle plates 22 serve to further mix the aggregate conveyed by the conveying helix 14 in the intended use, so that, through intensive contact with cooling water, targeted cooling of the aggregate is achieved.

[0128] As can be seen in Fig. 4, two blade plates 22 are provided for each 360° helix. The blade plates 22 are arranged offset from each other in the circumferential direction 21. They can, for example, be arranged opposite each other, as can be seen in Fig. 4.

[0129] In the embodiment shown in Fig. 4, the spiral conveyor 5 has a total of twelve paddle plates 22. Between two paddle plates 22 that follow one another in the longitudinal direction 23 of the conveyor helix 14, an angular offset a of 22.5° is formed in the circumferential direction 21. This optimizes the mixing of cooling water and aggregate, thus preventing aggregate fed into the conveyor helix 14 from passing through the conveyor helix 14 in batches without mixing.

[0130] Each blade 22 has rectangularly shaped large surfaces 24. These extend both in the longitudinal direction 23 and transversely to it, namely in the radial direction 25.

[0131] The spiral conveyor 5 also has disc-shaped end plates 26. In the illustrated embodiment, these are circular and each has through-openings 27. The through-openings 27 are of different sizes in their geometric design, with the through-opening 27 with the smaller diameter serving as the cooling water inlet 6, whereas the through-opening 27 with the larger diameter serving as the cooling water outlet 7.

[0132] A cooled aggregate leaving the cooling drum 2 described above can subsequently be fed into a silo 29 for storage, as shown in Figures 5 to 8.

[0133] Figures 5 to 8 each show a silo system 28, which in the illustrated embodiment has two silos 29. Of course, further silos 29 can also be provided, depending on the desired storage quantity.

[0134] A silo 29 has a storage bunker 30, which provides a volume space 31 for storage purposes. An inlet 32 ​​and an outlet 34 are also provided. Below the outlet 34, a transport device 35 with a conveyor belt 45 is provided, which serves to remove aggregate taken from a silo 29.

[0135] Cooled aggregate is fed into silo 29, preferably aggregate that has been cooled by means of a previously described device 1. To counteract warming of the aggregate in the storage bunker 30, the aggregate stored in silo 29 is cooled further.

[0136] For further cooling, cooling water is used, which is supplied to a silo 29 via a feed line 33. The cooling water then enters the storage bunker via the inlet 32 ​​and can flow through it to the outlet 34, resulting in further cooling of the aggregate stored in a storage bunker 30.

[0137] To enable the precise removal of cooled aggregate from silo 29 according to the recipe, i.e., without unpredictable adhesion of cooling water, a separation device 36 is provided on the outlet side of silo 29. This is shown in particular in Figures 7 and 8. In the illustrated embodiment, the separation device 36 provided for each silo 29 is designed in two stages and has a first separation stage 37 and a second separation stage 38. In the intended use, the aggregate obtained from these two separation stages 37 and 38 is free of cooling water.

[0138] The first stage 37 of the separation device 36 has two pipe sections 39 and 40, each of which is conically shaped. Each pipe section 39 or 40 is thus designed as a conical cylinder and accordingly has a tapered end section. The first pipe section 39 in the direction of passage 41 has a water-permeable outer surface, for example, a perforated outer surface. The second pipe section 40 in the direction of passage 41, however, has a closed outer surface.

[0139] As can be seen in particular in the illustrations according to Fig. 7 and Fig. 8, the first pipe section 39 in the passage opening 41 projects with its tapered end section into the second pipe section 40 in the flow direction 41. In this respect, there is a kind of cascade between the two pipe sections 39 and 40.

[0140] In its intended use, the first separation stage 37 results in the following operating principle. A mixture of cooling water and cooled aggregate leaves the storage bunker 30 via the outlet 34. This mixture comes into contact with the inner surface of the first pipe section 39. Since this section is permeable to water, the cooling water can pass through the surface, be collected, and then discharged. The aggregate, however, cannot pass through the surface of the first pipe section 39 and is conveyed to the second pipe section 40. Because the first pipe section 39 engages the second pipe section 40 with a tapered end, a reliable transfer of the aggregate from the first pipe section 39 to the second pipe section 40 is ensured. The aggregate exiting the second pipe section 40 can then be collected and transported away by means of a discharge chute 42.

[0141] The cooling water column in storage bunker 30, located directly above outlet 34, can pass through the two pipe sections 39 and 40 without collision, i.e., without being guided over the outer surface of the first pipe section 39. A certain amount of residual water thus still adheres to the aggregate exiting pipe section 40. To separate this residual water from the aggregate, a filter unit, for example in the form of a grate, is provided according to the second separation stage 38. This can be located downstream of the discharge chute 42 or be part of it. In any case, the filter unit provides a further separation between the residual cooling water and the aggregate, so that cooled aggregate suitable for fresh concrete production is obtained at the end of the separation system.

[0142] To prevent cooling water from the storage bunker 30 from passing through the two pipe sections 39 and 40 without collision, a conical baffle 43 is arranged inside the storage bunker 30. Its apex is oriented opposite the outlet 34. This ensures that cooling water can only flow out in a ring-shaped pattern around the baffle 43, causing the cooling water to impact the outer surface of the first pipe section 39 under the influence of gravity.

[0143] The aggregate, freed from cooling water according to the first and second separation stages, then reaches the transport device 35 described above via a chute 44.

[0144] The cooling water used to cool the aggregate stored in silo 29 is preferably process water originating from the cooling water outlet 7 of the aforementioned device 1. This has the advantage that any rock fragments, sediments, and / or suspended particles of the aggregate stored in silo 29 that may be entrained by the cooling water are removed, resulting in a particularly precise delivery of the cooled aggregate according to the recipe.

[0145] Reference sign

[0146] 1 device 25 24 large area

[0147] 2 Cooling drum 25 radial direction

[0148] 3 first cooling water circuit 26 end plate

[0149] 4 Housing 27 Through-hole

[0150] 5 spiral conveyors, 28 silo equipment

[0151] 6 Cooling water inlet 30 29 Silo

[0152] 7 Cooling water outlet 30 Storage bunker

[0153] 8 Direction of flow of cooling water 31 Volume space

[0154] 9 Conveying direction Aggregate 32 Inlet

[0155] 10 floatation tanks 33 feed line

[0156] 11 plate heat exchangers 35 34 outlet

[0157] 12 Second cooling circuit 35 Transport device

[0158] 13 Temperature sensor 36 Separation device

[0159] 14 Conveyor helix (spiral helix) 37 first stage

[0160] 15 slots, 38 second stage

[0161] 16 Cooling water 40 39 Pipe section

[0162] 17 Inlet point 40 Pipe section

[0163] 18 Connection spigots 41 Direction of passage

[0164] 19 Drive roller 42 Discharge chute

[0165] 20 Enclosure 43 Impact body

[0166] 21 Circumferential direction 45 44 Slide

[0167] 22 bucket plate 45 conveyor belt

[0168] 23 Longitudinal direction

Claims

Patent claims 1. Device for cooling aggregate for the production of fresh concrete, comprising a cooling drum (2) designed to continuously convey cooling water (16) and aggregate in countercurrent flow with mutual contact, characterized in that the cooling drum (2) has a cylindrical housing (4) and a spiral conveyor (5) arranged therein in a twisted manner, wherein the spiral conveyor (5) has a conveying helix (14) and paddle plates (22) arranged thereon, and that the cooling drum (2) has, in the longitudinal direction of the housing (4), an inlet for aggregate and an outlet (7) for cooling water (16) on one end and an outlet for aggregate and an inlet (6) for cooling water (16) on the other end.

2. Device according to claim 1, characterized in that two blade plates (22) are provided for each 360° helix, which are arranged offset from each other in the circumferential direction (21).

3. Device according to one of the preceding claims, characterized in that an angular offset (a) in the circumferential direction (21) of 20° to 25°, preferably of 22.5°, is formed between two paddle plates (22) following one another in the longitudinal direction (23) of the conveying helix (14).

4. System for providing cooled aggregate for the production of fresh concrete, comprising a device according to any one of the preceding claims 1 to 3 and a silo (29) for storing aggregate cooled by means of a device according to any one of the preceding claims 1 to 3.

5. System according to claim 4, characterized in that the silo (29) has a storage bunker (30) for cooled aggregate, an inlet (32) for cooling water and aggregate, and an outlet (34) for cooling water and aggregate.

6. System according to claim 5, which is configured to supply cooling water to the inlet (32) which originates as residual water from the device according to any one of the preceding claims 1 to 3.

7. System according to claim 5 or 6, characterized by a separating device (36) operatively connected to the outlet (34), which is configured to separate cooling water from cooled aggregate.

8. System according to claim 7, characterized in that the separating device (36) has two cone-shaped pipe sections (39, 40) which are arranged one after the other in the direction of passage (41) of the cooling water and the aggregate.

9. System according to claim 8, characterized in that the first pipe section (39) in the direction of passage (41) projects into the volume space provided by the other pipe section (40) with its conically tapered end section.

10. System according to claim 8 or 9, characterized in that the outer surface of the second pipe section (40) in the direction of passage (41) is closed.

11. System according to claim 8, 9 or 10, characterized in that the outer surface of the first pipe section (39) in the direction of passage (41) is designed to be water-permeable.

12. System according to one of the preceding claims 8 to 11, characterized in that the second pipe section (40) in the direction of passage (41) cooperates with a pouring trough (42) with its conically tapered end region.

13. System according to claim 12, characterized in that the separating device (36) has a filter unit which is located downstream of the discharge chute (42) or which is provided by the discharge chute (42).

14. System according to one of the preceding claims 5 to 13, characterized in that a conical impact body (43) is fluidically positioned upstream of the outlet (34) within the storage bunker (30), wherein the conical tip of the impact body (43) is formed opposite the outlet (34).

5. Method for cooling an aggregate for the production of fresh concrete, in which the aggregate and cooling water (16) are continuously conveyed in countercurrent flow and brought into contact with each other by means of a device according to one of the preceding claims 1 to 3.

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