Apparatus and method for cooling concrete

Abstract

The device for cooling concrete containing a given amount of water comprises an airtight container (20) defining a chamber (1) intended to accommodate a desired amount of concrete therein, an inlet opening (2) for the concrete into the chamber (1) and a pipe (3) communicating with the chamber (1) and extending from the chamber (1) to an outlet opening (5) for the concrete defined in the airtight container (20) at one end of the pipe (3) opposite the chamber (1). The pipe (3) is configured to convey the concrete from the chamber (1) towards the outlet opening (5). The device further comprises a vacuum pump (10) connected to the chamber (1) for adjusting the degree of vacuum in the chamber to at least partially cause evaporation of water from the concrete, and a condenser (12) arranged in the chamber (1) for condensing the evaporated water. The condenser (12) is configured for the condensed water to flow into the chamber (1) and / or into the concrete inside the pipe (3).

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for cooling concrete by advantageously utilizing the latent heat of vaporization of water. [Background technology]

[0002] During construction, concrete is placed in a fluid state and gradually changes to a rigid state according to a reaction known as concrete setting.

[0003] During this stage, the concrete needs to remain in a wet environment as long as possible to ensure that the complete process of hydration of the cement takes place and, as a result, the concrete has good mechanical and resistance properties.

[0004] At the same time, during the curing stage, the concrete must be kept below the maximum permissible temperature to prevent thermal stresses.

[0005] This problem is particularly evident when the placement of low-temperature concrete takes place in a high-temperature and / or low-humidity environment and / or when the placement is intended for large-scale works such as embankments and foundations. Indeed, in such cases, the increase in temperature generated by the hydration process of the cementitious materials can generate microcracks.

[0006] The formation of such microcracks can be prevented by limiting the temperature of the cooled concrete during pouring. In fact, there are strict standards regarding the temperature of cooled concrete during laying, which may require temperatures of 10°C or less.

[0007] A variety of mechanisms have been employed to meet these requirements.

[0008] Methods have been proposed and used to form concrete by cooling the components of the concrete, particularly the building aggregates, separately before mixing them.

[0009] To form concrete with water or air, for example, it is known to cool building aggregates before mixing.

[0010] Known systems for this purpose use ice and chilled water. These systems consume a significant amount of energy due to the need to maintain readily available reserves of chilled water and ice to compensate for heat dissipation and directly cool the concrete itself. Furthermore, while ice and chilled water are the only components of the mix with cooling capacity, they only constitute about 5 to 8% of the total mix weight, severely limiting the degree of cooling that can be achieved with these systems. Consequently, in a typical case where the average temperature of uncooled concrete is about 40°C, a system using only ice and chilled water cannot cool the building aggregate or concrete to a temperature below about 28°C.

[0011] Another prior art cooling system uses chilled water, ice, and chilled air blown into a refrigerated silo. This technique allows for the pre-cooling of coarse aggregates, but not fine aggregates. In fact, this technique requires that the aggregates themselves be large enough to form a "porous" mass that allows air to move between the stones, driven by a high-power fan. However, it is not possible to pre-cool both sand and cement, which make up approximately 45% of the total concrete mix, in this way. Thus, in a typical case where the average temperature of uncooled concrete is approximately 40°C, a system using chilled water, ice, and chilled air cannot cool the building aggregates or concrete to a temperature below 22°C. Furthermore, in addition to the problems described when only water and ice are used, the power level required to supply the fans is high, and in practical cases, the production equipment's nominal capacity is less than 1 m 3 There is an additional problem due to the fact that the cost can be as much as 1 kW per hour.

[0012] Furthermore, water and air cooling is not suitable for use with small-sized construction aggregates. In fact, the finest particles are washed away or blown away, altering the properties of the cooled material at the exit of the cooling process. Finally, the low porosity of fine aggregate deposits substantially prevents the flow of cool air between the particles.

[0013] In more sophisticated known systems, in addition to the use of cold water and ice, the coarser aggregate (gravel) is cooled on a conveyor belt by jets of cold water that are sprayed onto the gravel itself as it moves slowly along. However, the sand is passed through a rotating cylinder where a stream of cold air is blown in the opposite direction to the sand flow. Although this system is sophisticated, it is not capable of cooling the concrete to temperatures below 12°C. Furthermore, this solution involves additional components, which obviously contribute to increased costs and complexity of the equipment.

[0014] In addition to the drawbacks mentioned above, the above method requires considerable energy consumption, since the building aggregate must be kept cold after cooling until the concrete is mixed. Therefore, the additional cooling power required to maintain the building aggregate temperature at the desired level must be provided during the entire time between the cooling process and use. Furthermore, storing cooled building aggregate during a breakdown in one of the downstream devices in the concrete production and distribution line is costly. In fact, in the event of a shutdown or breakdown of upstream or downstream equipment, the temperature maintenance cannot be interrupted, since it can take more than a day to cool the entire hot aggregate silo.

[0015] It is clear how high the energy consumption associated with such a method is.

[0016] Furthermore, applicant has demonstrated that the above-described cooling systems impose excessively long cooling times, which can last for several hours.

[0017] Other known systems can use reduced pressure to cool the building aggregate, in which the building aggregate is wetted and fed into a reduced pressure chamber where reduced pressure is applied to cause evaporation of a given amount of water, thereby cooling the building aggregate.

[0018] The building aggregate thus cooled then receives cement to form the concrete mixture.

[0019] To obtain cooled concrete, it is therefore necessary to supercool the building aggregates to compensate for the heat provided as a result of the addition of the cement that has not been previously cooled. However, this supercooling is not only expensive, but also inefficient, since it is not possible to obtain a concrete mixture that is sufficiently cooled and, in any case, at the desired temperature.

[0020] Furthermore, known techniques for cooling construction aggregates of different sizes under reduced pressure are particularly inadequate. In fact, large diameter stones have a larger volume-to-surface area relationship than small stones. As a result, unlike small stones, which tend to cool more quickly as a result of their higher surface-to-volume relationship, the evaporation of water wetting large stones is wasted without their internal volume being cooled to the desired temperature.

[0021] Known systems for cooling construction aggregates under reduced pressure have been tested by the applicant and face various technical and thermodynamic limitations that make it extremely difficult to reach concrete temperatures below 15°C.

[0022] In fact, if the cement is not cooled, the aggregates will be overcooled to a level that is incompatible with the decompression technology used. It is therefore necessary to supply pre-cooled aggregates to these cooling units. For this pre-cooling of the aggregates, cooled, insulated hoppers are used, which entails additional investment and the consumption of electrical energy. Practical experiments have shown that in the case of pre-cooling of construction aggregates, the heat distribution is required for each m of the nominal capacity of the production equipment. 3 It has been shown that the average power consumption is approximately 1 kW per hour.

[0023] Furthermore, the prior art cooling process does not ensure control of the amount of residual water in the resulting mix and therefore does not ensure a correct water / cement ratio in the concrete.

[0024] This ratio must not be changed as it must be appropriate to characterize the concrete mixture according to the given mix design and to ensure the required performance level of the concrete based on the designer's requirements and the properties of the raw materials used.

[0025] Furthermore, the water / cement ratio is important to ensure both the correct fluidity of the mixture and, in particular, the ultimate resistance of the concrete.

[0026] In prior art cooling systems, the problem of uncertainty regarding the water percentage or water / cement ratio is exacerbated as such systems operate with larger water volumes.

[0027] Furthermore, prior art systems of evaporative cooling under reduced pressure are unable to comply with the mixing times and precision for measuring the product as stipulated by standards, and in particular are unable to prevent the risk of so-called concrete segregation after concrete formation.

[0028] Furthermore, prior art systems for cooling under reduced pressure by evaporation are inadequate in terms of both the energy and time required for the cooling process.

[0029] Furthermore, the cooling of the building aggregates that can be obtained with known systems is often insufficient to reach the desired pouring temperature.

[0030] It should be noted that in the present context, the term "concrete" refers to a building mass, preferably in a fluid state, obtained by mixing building aggregates (e.g., sand, gravel, crushed stone) in appropriate proportions with water and a binder (e.g., cement) that is activated in the presence of water. Summary of the Invention [Problem to be solved by the invention]

[0031] The technical problem addressed by the present invention is to provide an apparatus and method for cooling concrete that is structurally and functionally configured to at least partially overcome one or more of the drawbacks described with reference to the prior art above.

[0032] In particular, it is a first object of the present invention to provide an apparatus and method for cooling pumpable concrete.

[0033] It should be noted that in this context, the term "pumpable concrete" refers to concrete that is suitable for pumping as a result of its particle size distribution and cohesion. This type of concrete preferably contains aggregates with diameters of 30 or 32 mm or less, and even more preferably 25 mm or less.

[0034] A second object of the present invention is to provide an apparatus and method for continuously cooling concrete.

[0035] Another object of the present invention is to provide an apparatus and method for cooling concrete in a short period of time.

[0036] Another object of the present invention is to provide an apparatus for cooling concrete that is easily transportable.

[0037] Another object of the present invention is to provide an apparatus and method for cooling concrete at or very near the point of placement (cast-in-place concrete).

[0038] It is a further object of the present invention to provide an apparatus and method for cooling concrete that is low cost and simple in construction. [Means for solving the problem]

[0039] This problem is solved and these aims are achieved by the present invention by an apparatus and method for cooling concrete, preferably implemented in accordance with one or more of the accompanying claims.

[0040] In one aspect of the present invention, an apparatus is provided for cooling concrete (preferably of the pumpable type) containing a predetermined amount of water.

[0041] The apparatus comprises an airtight container defined therein: a chamber intended to contain a desired quantity of concrete, an inlet opening for the concrete into the chamber, and a pipe communicating with the chamber and extending from the chamber to an outlet opening for the concrete defined in the container at one end of the pipe opposite the chamber, the pipe being configured to convey the concrete from the chamber towards the outlet opening.

[0042] It should be noted that in the present context, the term "airtight" preferably means substantially airtight and refers to the state of the container in which the inlet and outlet openings are sealed. More preferably, an airtight container means that it is structurally suitable to withstand reduced pressure within the airtight container.

[0043] The apparatus further includes a vacuum pump connected to the chamber for adjusting a reduced pressure within the chamber to at least partially cause evaporation of water from the concrete, and a condenser disposed within the chamber for condensing evaporated water.

[0044] In one working configuration, the pipe preferably extends downward from the chamber, and even more preferably extends substantially vertically. With further reference to the working configuration, the pipe preferably meets a vertical level difference of at least 3 meters, and even more preferably 3 to 6 meters.

[0045] In a highly preferred embodiment, in the working configuration, the pipe has a vertical level difference of at least 4 meters, advantageously 4-5 meters. This configuration allows the formation of a (fluid) concrete column having a height such that it exerts a pressure of at least 1 atmosphere while passing through the pipe during operation, thereby ensuring the possibility of adjusting the negative pressure in the chamber.

[0046] The condenser is preferably arranged inside the chamber on the opposite side of the pipe and is advantageously arranged so that the condensed water flows, preferably as a result of gravity, e.g. by dripping, into the concrete inside the chamber and / or pipe. Advantageously, this arrangement allows the recovery, or at least substantial recovery, of the amount of water contained in the concrete at the start of the cooling process, so as to keep the water / cement ratio established by the concrete mix design substantially unchanged.

[0047] The chamber may be tapered towards the pipe to facilitate the flow of condensate, and more generally concrete, from the chamber towards the pipe.

[0048] According to another advantageous aspect, the pipe is configured to hermetically seal the chamber from the outlet opening by means of concrete which, when passing through the pipe, prevents the passage of air through the pipe from the outlet opening towards the chamber.

[0049] It should be noted that in this context, "sealed" preferably means tightly closed so as to be airtight or substantially airtight.

[0050] This configuration also makes it possible to maintain a reduced pressure in the chamber when the outlet opening is open to discharge the concrete, thereby ensuring the possibility of producing a continuous flow of cooled concrete.

[0051] It will be appreciated that the pipe preferably comprises a regulating device for regulating the flow of concrete through the outlet opening, which may for example comprise or consist of a valve or a pump or another means suitable for regulating the flow of concrete through the outlet opening.

[0052] In a preferred embodiment, the apparatus comprises a concrete supply pipe connected to the inlet opening.

[0053] In the operating configuration, the supply pipe preferably extends downwardly from the inlet opening, and even more preferably satisfies substantially the same vertical level difference as the other pipe.

[0054] Advantageously, the supply pipe is configured to convey concrete from the outside towards the inlet opening while at the same time sealing the chamber airtight against external pressure with the concrete preventing the passage of air through the supply pipe from the outside towards the inlet opening.

[0055] It should be noted that in this context, "external pressure" preferably means the atmospheric pressure outside the airtight container.

[0056] In one aspect, the present invention relates to a method for cooling concrete (preferably of the pumpable type) containing a predetermined amount of water by means of the device described above, said method comprising the steps of: supplying concrete at an initial temperature into the chamber through an inlet opening; conveying the concrete from the chamber to a pipe; adjusting the pressure in the chamber to reach a reduced pressure that at least partially causes evaporation of water from the concrete and consequently cools the concrete to a final temperature that is lower than the initial temperature; condensing water evaporated from the concrete in the chamber; Allowing the condensed water to flow into the concrete; removing the concrete at the final temperature from the pipe through an outlet opening.

[0057] It should be noted that in a preferred embodiment, the pressure downstream of the outlet opening (and therefore outside the airtight container) is equal to atmospheric pressure.

[0058] Advantageously, the method allows the chamber to be hermetically sealed from the outlet opening by concrete that, as it passes through the pipe, prevents the passage of air through the pipe from the outlet opening towards the chamber. This allows a reduced pressure to be maintained in the chamber even when the outlet opening is open to the outside to discharge the concrete from the device. In this way, the concrete can be removed from the outlet opening continuously (or, if applicable, preferably at regular time intervals) without interrupting the upstream cooling process.

[0059] Advantageously, the method allows, if applicable, for the concrete to be conveyed from the outside towards the inlet opening through the supply pipe by means of a pump suitable for pumping the concrete, whereby it is also possible to preferably hermetically seal the inlet opening against external pressure by the concrete which, when passing through the supply pipe, prevents the passage of air through the supply pipe from the outside towards the inlet opening.

[0060] According to another advantageous aspect, in order to regulate the subatmospheric pressure in the chamber, the concrete passing through the above-mentioned pipes forms respective (fluid) columns having a height such that they exert a pressure of at least 1 atmosphere.

[0061] The features and advantages of the present invention will be better understood from the detailed description of a preferred embodiment given by way of non-limiting example with reference to the sole figure of the accompanying drawings, namely Figure 1, which is a schematic illustration of an apparatus for cooling concrete according to the invention. [Brief explanation of the drawings]

[0062] [Figure 1] 1 is a schematic diagram of an apparatus for cooling concrete according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0063] In FIG. 1, reference numeral 100 designates an apparatus for cooling concrete.

[0064] The device 100 comprises an airtight container 20 suitable for withstanding reduced pressure, in which is defined a chamber 1 intended to contain a desired amount of concrete, an inlet opening 2 for the flow of concrete into the chamber 1, a pipe 3 communicating with the chamber 1 through a mouth 4 of the pipe 3 connected to the chamber 1, and an outlet opening 5 for the concrete from the pipe 3, defined in the end of the pipe 3 on the side opposite the chamber 1.

[0065] The concrete is intended to flow from the inlet opening 2 to the outlet opening 5 by passing through the chamber 1 and then through the pipe 3 .

[0066] Preferably, the pipe 3 extends longitudinally along an axis X, and even more preferably, the chamber 1 extends coincident with the pipe 3 along the axis.

[0067] In some embodiments, the inlet opening 2 is oriented radially relative to the axis X, while the outlet opening 5 may be oriented in line with the axis X. It will be appreciated that in some embodiments, the outlet opening 5 may also be oriented radially relative to the axis X.

[0068] The chamber 1 is delimited by a connection portion 6 to the pipe 3 , a top wall 7 opposite the connection portion 6 , and at least one side wall 8 extending from the connection portion 6 to the top wall 7 .

[0069] Preferably, the connection portion 6 tapers towards the mouth 4 of the pipe 3. In a preferred embodiment, the connection portion 6 defines a truncated cone, the tip of which is directed towards the pipe 3.

[0070] In some embodiments, chamber 1 is axisymmetric about axis X. Side wall 8 is preferably cylindrical, while top wall 7 may be substantially planar. It will be appreciated that the configuration of chamber 1 can be adapted to the limitations regarding production capacity demands and space requirements imposed by different applications of the system.

[0071] In a preferred embodiment, the inlet opening 2 is defined through the connecting portion 6 or the side wall 8 or at the boundary between them, preferably at an intermediate position between the top wall 7 and the mouth 4 of the pipe 3 .

[0072] Advantageously, the pipe 3 has a length L suitable to receive a concrete column having a height such that it exerts a pressure of (at least) 1 atmosphere while passing through the pipe 3 .

[0073] The density of concrete is generally 2200 to 2600 kg / m 3 It should be noted that in a highly preferred embodiment, the length L of the pipe 3 is therefore at least 3 metres, preferably between 3 and 6 metres. Even more preferably, the length L is at least 4 metres, advantageously between 4 and 5 metres.

[0074] In a preferred embodiment, the pipe 3 has a hollow circular cross section. Advantageously, its diameter is selected to ensure the desired flow rate and the desired speed of passage of the concrete through the pipe 3. To this end, the diameter of the pipe 3 may be constant or may be variable over the longitudinal extension of the pipe itself.

[0075] According to another advantageous aspect, a regulating device 9 is provided for regulating the flow of concrete through the outlet opening 5 of the pipe. Preferably, the regulating device 9 is configured to keep the outlet opening 5 (hermetically) closed and to open it temporarily when it is desired to remove a desired amount of cooled concrete (e.g., a volume in the range of 300 to 400 liters). In some embodiments, the regulating device 9 is configured to open the outlet opening 5 at regular time intervals at a desired frequency. It will be appreciated that by appropriately adjusting the regulating device 9 relative to the supply flow rate, removal of cooled concrete may also be performed continuously.

[0076] It should be noted that the amount of concrete to be removed is fixed, and the frequency with which the regulating device 9 opens the outlet opening 5 depends on the flow rate of concrete through the pipe 3. The pipe 3 is therefore advantageously dimensioned according to the desired frequency with which the regulating device 9 opens the outlet opening 5. To this end, it is envisaged that the end portion 30 of the pipe 3 immediately upstream of the outlet opening 5 and the regulating device 9 may have a larger cross section (e.g., in terms of diameter or surface area) relative to the rest of the pipe 3. This configuration makes it possible to form a discharge extension of sufficient volume in the end portion 30 so that the desired amount of concrete is discharged each time the outlet opening 5 controlled by the regulating device 9 is opened, while at the same time maintaining a concrete column of the desired height inside the pipe 3.

[0077] The apparatus 100 further comprises a vacuum pump 10 connected to the chamber 1 by an intake pipe 11 for creating and maintaining a reduced pressure inside the chamber 1 .

[0078] It should be noted that in this context, the term "reduced pressure" refers to a pressure condition below atmospheric pressure.

[0079] In a preferred embodiment, the vacuum pump 10 has an operating range of 10 to 100 mbar, or possibly 30 to 70 mbar.

[0080] Preferably, the intake pipe 11 is connected to the chamber 1 on the side opposite the mouth 4 of the pipe 3. For example, the intake pipe 11 can be connected to the top wall 7 or to the side wall 8 area.

[0081] The apparatus 100 further comprises a condenser 12 located inside the chamber 1, preferably opposite the mouth 4 of the pipe 3. In some embodiments, the condenser 12 is attached to the top wall 7.

[0082] It should be noted that in this context the term "condenser" preferably refers to a heat exchanger.

[0083] Advantageously, the condenser 12 is of the tubular type, which configuration makes it possible to minimize the introduction of air into the condenser's connections in the chamber 1. According to another advantageous aspect, a cooler 13 is provided which is connected to the condenser 12 and provides a cooling fluid passing through the condenser 12.

[0084] In a preferred embodiment, the device 100 comprises a supply pipe 14 for concrete to the inlet opening 2 .

[0085] In some embodiments, the inlet opening 2 is defined at the end of a supply pipe 14 connected to the chamber 1, for example in the region of the connecting portion 6 or the side wall 8, or at the boundary between these two, preferably at an intermediate position between the top wall 7 and the mouth 4 of the pipe 3.

[0086] In some embodiments, the end of the supply pipe 14 that defines the inlet opening 2 projects into the interior of the chamber 1, preferably until it reaches the axis of symmetry X of the chamber itself. Even more preferably, the end of the supply pipe 14 that projects into the interior of the chamber 1 is directed towards the connecting part 6, or in any case away from the condenser 12. This configuration makes it possible to direct the flow of concrete from the inlet opening 2 into the pipe 3.

[0087] Advantageously, the supply pipe 14 has a hollow circular cross section which is preferably constant over its entire longitudinal length.

[0088] The supply pipe 14 may be drawn from a tank 15 containing concrete, preferably pumpable concrete, which may be at ambient temperature and / or pressure. In a preferred embodiment, the supply pipe 14 is substantially parallel to the pipe 3 over at least part of its entire longitudinal length. Preferably, the part of the supply pipe 14 has a length L' of at least 3 meters, even more preferably between 3 and 6 meters. In a highly preferred embodiment, the length L' is at least 4 meters, advantageously between 4 and 5 meters. It should be noted that in a highly preferred embodiment, the length L' is substantially equal to the length L of the pipe 3.

[0089] Advantageously, a pump 16 is provided which is suitable for pumping concrete and is connected to the supply pipe 14 in order to supply concrete under pressure from the tank 15 to the inlet opening 2. For this purpose, the pump 16 has an operating range which ensures, with an appropriate margin, a regular supply of the system.

[0090] To control the parameters of the concrete cooling process, the device 100 may include one or more sensors that may be selected from a pressure sensor 17, a temperature sensor 18, a level sensor 19, and a flow rate sensor 21, which may be connected to the chamber 1 and / or the pipe 3 and / or the condenser 12.

[0091] In a preferred embodiment, at least one pressure sensor 17 is provided, connected to the chamber 1 , preferably opposite the mouth 4 of the pipe 3 .

[0092] In a preferred embodiment, at least one temperature sensor 18 is provided which is connected to the chamber 1 (preferably in the region of the connection part 6) and / or the pipe 3 (preferably in the region of the mouth 4) or to the boundary between the chamber 1 and the pipe 3.

[0093] Preferably, there is provided at least one temperature sensor 18 connected to the condenser 12. Even more preferably, there are provided two temperature sensors 18, one connected to the inlet of the condenser 12 and the other connected to the outlet of the condenser.

[0094] In some embodiments, a plurality of level sensors 19 are provided, distributed over the longitudinal extent of the chamber 1 and / or pipe 3 and configured to measure the level of concrete in the chamber 1 and / or pipe 3, respectively.

[0095] In a preferred embodiment, there is provided at least one level sensor 19 connected to the chamber 1 (preferably on the side facing the pipe 3) and another level sensor 19 connected to the pipe 3 (preferably at an intermediate position between the mouth 4 and the outlet opening 5).

[0096] In a preferred embodiment, the chamber 1 is provided with two level sensors 19, preferably connected in the region of the connection part 6. More preferably, one of the two level sensors 19 is connected to the connection part 6 on the side opposite the pipe 3, and the other is connected to the connection part 6 on the side facing the pipe 3 (e.g. in the region of the mouth 4).

[0097] The level sensor 19 may be of the continuous type or may be a level sensor for a defined threshold. Advantageously, the defined threshold level sensor can operate with various measurement methods, such as, for example, capacitive resistive, microwave, radar, ultrasonic or gravimetric.

[0098] In some embodiments, there is provided at least one flow sensor 21 connected to the condenser 12 and configured to measure the flow rate of the cooling fluid per unit time.

[0099] Advantageously, a control unit is provided for the vacuum pump 10 operatively connected to at least one pressure sensor 17 of the chamber 1 for adjusting the degree of vacuum in the chamber 1 depending on the pressure measured by the sensor 17.

[0100] According to another advantageous aspect, a control unit for the cooler 13 is provided operatively connected to the at least one temperature sensor 18 in order to regulate the amount of heat removed from the condenser 12 according to the temperature of the concrete measured by the sensor 18. It can be appreciated that the amount of heat removed by the condenser 12 depends on the amount of cooling fluid (advantageously measured by the flow sensor 21) and the temperature difference at the inlet and outlet of the condenser (advantageously measured by the temperature sensor 18).

[0101] According to another advantageous embodiment, a control system is provided for the pump 16 and the regulating device 9, which is connected to one or more level sensors 19 in order to regulate the flow rate of concrete passing through the device according to the concrete level measured by the sensors 19. This arrangement makes it possible to regulate the concrete flow rate and level suitable to ensure the continuity of the process.

[0102] In the working configuration, the device 100 is configured so that the pipe 3 extends downwardly from the chamber 1. Preferably, in the working configuration, the supply pipe 14 also extends downwardly from the chamber 1. Even more preferably, in the working configuration, the supply pipe 14 extends downwardly from the inlet opening 2.

[0103] In this configuration, the chamber 1 is preferably placed at an elevated position (relative to the ground) by a support structure, and preferably the axis X of the pipe 3 (and of the chamber 1) is oriented substantially vertically.

[0104] It will be noted that in the operating configuration, the chamber 1 together with the pipe 3 forms a structure similar to that of a surge tank of the type used in waterways.

[0105] It will be appreciated that in some cases the pipe 3 may be oriented obliquely relative to the ground, provided that the longitudinal extension of the pipe 3 from the mouth 4 to the outlet opening 5 satisfies a vertical level difference. Preferably, this level difference is at least 3 metres, even more preferably 3 to 6 metres. In a highly preferred embodiment, this level difference is at least 4 metres, advantageously 4 to 5 metres.

[0106] In its operational configuration, the supply pipe 14 is also preferably oriented substantially vertically over at least a portion of its longitudinal extent. It will be appreciated that the supply pipe 14 can be raised at an angle to the ground and / or form a curve along its longitudinal extent, provided that, from its withdrawal position within the tank 15 to the inlet opening 2, the supply pipe 14 satisfies a vertical level difference, preferably a vertical level difference substantially equal to that satisfied by pipe 3. Preferably, the vertical level difference satisfied by the supply pipe 14 is at least 3 meters, and even more preferably, 3 to 6 meters. In a highly preferred embodiment, the vertical level difference satisfied by the supply pipe 14 is at least 4 meters, and advantageously, 4 to 5 meters. This configuration means that, during operation, the concrete column passing through the supply pipe 14 has a height substantially equal to that of the concrete column passing through pipe 3.

[0107] The operation of the device 100 is described below.

[0108] Concrete, preferably of the pumpable type and containing a predetermined amount of water, is fed into the device 100 from a tank 15 at an initial temperature Ti (e.g., ambient temperature) through a supply pipe 14 and an inlet opening 2 as a result of the effect of negative pressure exerted by a vacuum pump 10 and / or the effect of positive pressure exerted on the concrete by a delivery pump 16.

[0109] Inside the chamber 1 the concrete is guided downwards from the connection part 6 towards the mouth 4 of the pipe 3, preferably as a result of gravity.

[0110] The concrete continues to flow downward from the mouth 4 through the pipe 3, preferably as a result of gravity, accumulating within the pipe 3 and forming a column of concrete as it passes through the pipe 3. In a preferred embodiment, such a column fills the pipe 3 over its entire length L. The flow of concrete through the pipe 3 is regulated by a regulator 9 which blocks the discharge of concrete from the outlet opening 5.

[0111] Advantageously, the regulator 9 and the delivery pump 16 are synchronized with each other or in any case cooperate to maintain in the pipe 3 a column of concrete having the desired height.

[0112] When the regulator 9 opens the outlet opening 5, the concrete is free to discharge from the pipe 3 through the outlet opening 5, but the chamber 1 still remains sealed against external pressure (atmospheric pressure) because the column of concrete passing through the pipe 3 has such height and cohesion that it creates a lid-like barrier or blockage that prevents the introduction of air from the outlet opening 5 into the chamber 1 during the period that the outlet opening 5 remains open.

[0113] It should be noted that chamber 1 also remains sealed against external pressure in the area of ​​supply pipe 14. In fact, the concrete passing through supply pipe 14 prevents the introduction of air from the outside towards chamber 1, in a similar way to what happened through pipe 3.

[0114] For this purpose, it can be seen that it is particularly advantageous to use pumpable concrete to obtain airtightness through the pipes 3, 14, since this concrete, with its cohesion, prevents the formation of porosity and ensures the formation of a lubricating layer on the sliding surfaces of the pipes 3, 14 that is able to prevent the introduction of air.

[0115] This configuration allows the chamber 1 to be sealed airtight, so that the vacuum pump 10 can adjust the pressure Po inside the chamber 1 itself via the intake pipe 11.

[0116] During operation, care must be taken that each column of concrete, having substantially the same height, moves in the pipe 3 and in the supply pipe 14 so as to exert a pressure of (at least) 1 atmosphere.

[0117] In this way, the airtightness of the chamber 1 is ensured, and the pressure Po inside the chamber 1 can be adjusted to be lower than atmospheric pressure by the vacuum pump 10.

[0118] In this situation, the vacuum pump 10 adjusts the reduced pressure in the chamber 1 so as to at least partially evaporate the water from the concrete. The amount of water evaporated at this stage may be, for example, 10-15% of the amount of water initially contained in the concrete introduced into the device 100.

[0119] It will be appreciated that evaporation of water involves subtraction of an amount of energy corresponding to the latent heat of vaporization of water, and therefore involves cooling the concrete from an initial temperature Ti to a final temperature Tf (e.g., 10°C) lower than the initial temperature Ti.

[0120] By appropriately adjusting the pressure Po and therefore the degree of vacuum in the chamber 1, it is possible to achieve the desired final temperature Tf. For example, the degree of vacuum can be 10 to 100 mbar, or in some cases 30 to 70 mbar.

[0121] The water evaporated from the concrete remains in the chamber 1 and condenses in contact with the heat exchange surfaces of the condenser 12. Indeed, as a result of the passage of the cooling fluid, the condenser 12 removes the latent heat from the water evaporated from the concrete. The water evaporated from the concrete therefore condenses, i.e. changes from a gaseous state to a liquid state. According to another advantageous aspect, the water thus condensed returns to the evaporated concrete, thereby ensuring compliance with the predetermined water / cement ratio during the entire process.

[0122] Preferably, the condensed water falls back onto the concrete as a result of gravity, for example by dripping, from the surface of the condenser 12 down towards the concrete below inside the chamber 1 and / or pipe 3 .

[0123] Advantageously, care must be taken to ensure that the condensed water returning to the concrete does not cause the phenomenon of concrete segregation, since the introduction of concrete into the chamber 1 through the inlet opening 2 and the evaporation process within the chamber 1 are turbulent phenomena, which ensure a constant and active remixing of the concrete.

[0124] The process of evaporation of water from the concrete, and consequently the resulting remixing, advantageously includes both the concrete passing through the chamber 1 and the concrete present in the pipe 3, at least at its mouth 4.

[0125] Moreover, such remixing ensures uniform cooling of the concrete not only on the surface but also at great depths.

[0126] The time it takes for the concrete to pass through the pipe 3 may be less than one minute (e.g., 30 to 40 seconds), but the flow rate of the pipe itself (e.g., 60 to 100 m 3 / h).

[0127] Once the concrete to be cooled is charged into the chamber 1, it can be removed through the outlet opening 5, ensuring the continuity of the cooling process and therefore an uninterrupted supply of concrete without any downtime.

[0128] Advantageously, the concrete discharged from the outlet opening 5 has substantially the same amount of water as the concrete introduced and a final temperature Tf suitable for pouring, so that the concrete discharged from the outlet opening 5 can be poured directly or poured into a concrete mixer for transport to the place of use.

[0129] It may be noted that the final temperature Tf depends on factors such as the thermal inertia and amount of concrete placed in chamber 1, the initial temperature Ti of the concrete, and the amount of water evaporated / condensed during the process. By acting on the above variables, it is possible to obtain concrete with the desired final temperature Tf.

[0130] The present invention thereby solves the problems described while achieving several advantages, including the following:

[0131] An energy-efficient process that allows the concrete to be cooled continuously with no downtime. Energy-efficient process, allowing coolers to be used within their best performance range Energy-efficient process as it affects all components of the concrete, - The concrete can be cooled to a temperature of 10°C or less. The ability to recover the condensate in such a way that the amount of water provided in the concrete according to the concrete mix design is not substantially changed; A cooling process that allows for ready-to-manufacture concrete to be cooled in a short time; A cooling process that allows the concrete to be cooled in real time, without being affected by the conditions of upstream or downstream equipment and without requiring energy for pre-cooling and / or maintaining the temperature of the building aggregates; Devices for cooling concrete with minimal thermal inertia, making it possible to start the cooling process in a short time, without the need for pre-cooling or storage and maintenance of cooled components of the device; Simple and compact device, A mobile device that can be easily installed at the site where concrete is being poured.

Claims

1. An apparatus (100) for cooling concrete containing a predetermined amount of water, comprising: an airtight container (20) defined in it a chamber (1) intended to contain a desired quantity of concrete, an inlet opening (2) for the entry of said concrete into said chamber (1), and a pipe (3) communicating with said chamber (1) and extending from said chamber (1) to an outlet opening (5) for said concrete defined in said airtight container (20) at one end of said pipe (3) opposite said chamber (1), said pipe (3) being adapted to convey said concrete from said chamber (1) towards said outlet opening (5); a vacuum pump (10) connected to the chamber (1) for adjusting the degree of vacuum in the chamber (1) to at least partially cause evaporation of the water from the concrete; a condenser (12) arranged inside the chamber (1) for condensing the evaporated water, the condensed water being configured to flow into the chamber (1) and / or the concrete inside the pipe (3); An apparatus (100) comprising:

2. 2. The apparatus (100) according to claim 1, wherein the pipe (3) is configured to hermetically seal the chamber (1) from the outlet opening (5) by the concrete preventing the passage of air through the pipe (3) from the outlet opening (5) towards the chamber (1) when passing through the pipe (3).

3. 3. The device (100) according to claim 1 or 2, wherein the pipe (3) extends downwards from the chamber (1) in an operating configuration.

4. 4. The device (100) according to any one of claims 1 to 3, wherein the pipe (3) extends substantially vertically in an operational configuration.

5. 5. The device (100) according to any one of claims 1 to 4, wherein the pipe (3) in its working configuration satisfies a vertical level difference of at least 3 meters.

6. An apparatus (100) as described in any one of claims 1 to 4, wherein the pipe (3) in an operating configuration satisfies a vertical level difference of 3 to 6 meters.

7. An apparatus (100) as described in any one of claims 1 to 4, wherein the pipe (3) in an operating configuration satisfies a vertical level difference of 4 to 5 meters.

8. 8. Apparatus (100) according to any one of the preceding claims, wherein the pipe (3) comprises a regulating device (9) for regulating the flow of the concrete through the outlet opening (5).

9. 9. The device (100) according to any one of claims 1 to 8, wherein the chamber (1) tapers towards the pipe (3).

10. 10. The device (100) according to any one of claims 1 to 9, wherein the condenser (12) is arranged inside the chamber (1) on the opposite side of the pipe (3).

11. 11. The device (100) according to any one of claims 1 to 10, comprising a supply pipe (14) for supplying concrete connected to the inlet opening (2).

12. 12. The apparatus (100) of claim 11, wherein the supply pipe (14) extends downwardly from the inlet opening (2) in an operative configuration.

13. 13. The device (100) according to claim 11 or 12, wherein the pipe (3) and the supply pipe (14) satisfy substantially the same vertical level difference in the working configuration.

14. 14. The apparatus (100) according to any one of claims 11 to 13, wherein the supply pipe (14) is configured to transport the concrete from the outside towards the inlet opening (2) while at the same time sealing the chamber (1) airtight against external pressure by the concrete, which when passing through the supply pipe (14), prevents the passage of air through the supply pipe (14) from the outside towards the inlet opening (2).

15. 15. A method for cooling concrete containing a predetermined amount of water by means of a device (100) according to any one of claims 1 to 14, comprising the steps of: - feeding the concrete at an initial temperature (Ti) into the chamber (1) through the inlet opening (2); - conveying the concrete from the chamber (1) to the pipe (3); adjusting the pressure (Po) in the chamber (1) to reach a reduced pressure that at least partially causes evaporation of the water from the concrete and consequently cools the concrete to a final temperature (Tf) that is lower than the initial temperature (Ti); - condensing the water evaporated from the concrete in the chamber (1); - allowing the condensed water to flow into the concrete; - removing said concrete from said pipe (3) through said outlet opening (5) at said final temperature (Tf).

16. 16. The method of claim 15, comprising hermetically sealing the chamber (1) from the outlet opening (5) by the concrete preventing the passage of air through the pipe (3) from the outlet opening (5) into the chamber (1) when passing through the pipe (3).

17. A method as claimed in claim 15 or 16, comprising transporting the concrete from the outside towards the inlet opening (2) through a supply pipe (14).

18. 18. The method of claim 17, comprising hermetically sealing the inlet opening (2) against external pressure by the concrete, which prevents the passage of air from the outside through the supply pipe (14) to the inlet opening (2) when passing through the supply pipe (14).

19. 19. A method according to any one of claims 15 to 18, wherein the concrete passing through the pipe (3) and / or the supply pipe (14) forms respective columns having a height such that they exert a pressure of at least 1 atmosphere.

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