JPH0367612A - Method of cooling aggregate - Google Patents

Abstract

PURPOSE:To cool the aggregates efficiently at a low cost by spouting pressurized air successively or intermittently at spaces defined by aggregates or spaces defined by a storage vessel in which the aggregates are accommodated, and aggregates. CONSTITUTION:Pressurized air produced by an air compressor 16 is stored temporarily in a receiver tank 40 in order to be controlled in its pressure. And then, passing through a flow rate control valve 44 and a compression valve 46, it expands adiabatically and is sent in becoming low temperature to at least one of both pipe members 24, 26, after that, spouts from a nozzle 22 into aggregates 12. The pressurized air spouts into the spaces defined by the aggregates 12 and expands immediately, and then moves upward in continuing further expansion which goes on until the pressure becomes equal to the atmo spheric pressure. The rapid expansion of the pressurized air brings about the lowering of temperature, and it deprives heat threrefrom while flowing in con tact with particles, finally, goes away from the open-end of a bottle 14. In this fashion, particles are cooled therein. It is preferable that the aggregates 12 have been wetted, and the compressed air can be supplied successively and intermittently thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is aimed at reducing the mixing temperature of concrete.
The present invention relates to a method for cooling aggregate used for the purpose of cooling aggregates.

(Conventional technology) Conventionally, to cool aggregates, air cooling methods in which cold air is blown onto the aggregates, water cooling methods in which the aggregates are immersed in cold water, and vacuum cooling methods in which the aggregates are placed under low pressure have been used. There is.

(Problem to be solved by the invention) However, implementing the conventional air cooling method and water cooling method requires large-scale refrigeration equipment, and implementing the vacuum cooling method requires large-scale vacuum generation equipment. shall be. In order to construct this large-scale facility, we decided to cool the aggregate using the air cooling method, water cooling method, and vacuum cooling method. The drawback was that it was expensive.

SUMMARY OF THE INVENTION An object of the present invention is to provide an aggregate cooling method that can efficiently cool aggregates at low cost in order to eliminate the drawbacks of the conventional methods.

(Means for Solving the Problems, Actions and Effects of the Invention) In the aggregate cooling method according to the present invention, a space defined by a large number of particles such as sand and gravel in the aggregate, that is, a space constituting the aggregate; Alternatively, compressed air is blown out in a space defined by a storage container containing aggregate and the aggregate.

According to the present invention, the compressed air ejected into the space expands, and the temperature decreases along with the expansion.

The expanded air, whose temperature has been lowered, flows upward between the constituent particles of the aggregate while continuing to expand and lower its temperature, and removes heat from the constituent particles of the aggregate that it comes into contact with during the flow. As a result, the aggregate is cooled.

Compressed air can be generated cheaply and in large quantities using simple equipment such as near compressors, compared to supplying cooling air and water and creating a vacuum, which are necessary for carrying out conventional methods. can be done.

The aggregate can be pre-wetted with water. The water adhering to the surface of each particle of aggregate evaporates while the aggregate is left to stand, and the flowing air transports the water vapor to promote evaporation. Therefore, a large amount of heat of vaporization is removed from each particle during evaporation. Therefore, each particle receives the cooling effect caused by the expansion of the compressed air and the cooling effect caused by the evaporation of the water, and as a result, a higher cooling effect can be achieved. Water at room temperature may be used to wet the aggregate, and no special equipment is required for this purpose.

Furthermore, the compressed air can be cooled prior to being ejected. If compressed air at a lower temperature is used, the temperature of the expanded air will be even lower, so that the cooling effect of the aggregate can be further enhanced. The degree of cooling of the compressed air is not as high as that required when implementing the conventional method, and therefore a simple cooling facility is sufficient.

The compressed air can be supplied continuously or intermittently.

(Example) The aggregate cooling method according to the present invention can be implemented using a cooling device 10 shown in the accompanying drawings.

The cooling device 10 shown in FIG. 1 includes a bin 14 with an open top, which is a storage container for storing aggregate 12 made of a large number of particles such as gravel or sand shown in the embodiment, and a bin 14 with an open top. and a near compressor 16 for supplying the air.

According to the invention, the aggregate 12 is cooled by blowing said compressed air into the aggregate.

The bin 14 has a downwardly convex support portion 1 on which the aggregate 12 is placed.
8. The support part 18 has an outlet 2 for taking out the aggregate 12 that has been supplied from the open upper end of the bin 14 and has finished cooling.
has 0. Later-described side portion 28 defining the outer wall surface of the bottle 14
It is preferable that the side portion 28 is formed of a heat insulating material or that a heat insulating material is embedded in the side portion 28 in order to reduce heat transfer into and out of the bottle 14 through the side portion.

a plurality of outlets or nozzles 22 for the compressed air;
Two tube members 24 and 26 having a diameter are arranged parallel to each other inside the bottle 14 and spaced apart from each other in the vertical direction. Both tube members 24 , 26 extend perpendicular to the axis of the bottle 14 .

A lower tube member 24 having a smaller length dimension is supported on the support portion 18 of the bin 14 near its lower portion, and an upper tube member 26 having a larger length dimension is supported on the support portion 18 of the bin 14 above the support portion 18. is supported on the side portion 28 of.

Both tube members 24 , 26 connect to the near compressor 16 via a conduit 30 extending through the side 28 and support 18 of the bin 14 and a conduit 32 extending through the side 28 of the bin 14 . It is connected to the. A conduit 30 connected to the lower tube member 24 , a conduit 32 connected to the upper tube member 26 , and a conduit 34 connected to the near compressor 16 are connected to each other outside the bin 14 via a stop valve 40 . connected to each other.

The conduit 34 is sequentially provided with a receiver tank 40 with a pressure reducing valve, a stop valve 42, a flow control valve 44, a pressure reducing valve 46 with a pressure gauge, etc. from the near compressor 16 toward the bin 14.

Compressed air generated by the near compressor 16 is temporarily stored in a receiver tank 40, and the pressure is adjusted during this time. The compressed air in the receiver tank flows out by opening the stop valve 42, passes through the flow rate control valve 44, and further passes through the pressure reducing valve 46, where it expands adiabatically. 24 and 26 and is ejected from the nozzle 22 into the aggregate 12.

The compressed air is ejected into a space defined by a large number of particles constituting the aggregate 12, expands immediately, and moves upward through the aggregate 12 while continuing to expand.

This expansion continues until the pressure of the compressed air becomes equal to atmospheric pressure. The rapid expansion of the compressed air, similar to adiabatic expansion, results in a decrease in the temperature of the compressed air. The air, whose temperature has decreased, removes heat from the constituent particles of the aggregate while flowing in contact with the particles, and is then discharged to the outside from the open upper end of the bottle 14. In this way, the particles are cooled.

The pressure reducing valve 46 can be omitted. However, by arranging the pressure reducing valve 46, the temperature of the compressed air can be lowered twice: after passing through the pressure reducing valve and after being ejected into the aggregate 12. This allows the aggregate 12 to be cooled more effectively. Conduit 3 instead of pressure reducing valve
It is also possible to cool a portion of the compressed air 4, for example with liquid nitrogen (LN2), thereby lowering the temperature of the compressed air passing through the conduit 34.

Furthermore, before putting the aggregate 12 into the bin 14, water (surface water) may be attached to part or all of the surface of the constituent particles of the aggregate 12 by sprinkling water on it or passing it through water. desirable. According to this, the surface water of the aggregate 12 evaporates within the bottle 14, and the air that is ejected into the aggregate 12 and rises therein promotes the evaporation of the surface water. Due to the evaporation, heat of vaporization is removed from the constituent particles of the aggregate 12, and the aggregate 1
2 is further promoted. In this case, it is therefore desirable to supply drier compressed air (eg, at a temperature of 30% or less).

The compressed air can be supplied continuously or intermittently, taking into account the type and temperature of the aggregate 12, the supply amount and temperature of the compressed air, and the like.

To ensure cooling of the aggregate 12, a plurality of thermometers 48 are placed inside the bin 12 for measuring the temperature of the aggregate 12.

The tube members 24,26 with nozzles 22 have a quantity of 2
The number of nozzles 22 may be 3 or more or 1 instead of the illustrated example, and the number of nozzles 22 may be increased or decreased as necessary. Moreover, the pipe members 24 and 26 can be arranged, for example, so as to intersect three-dimensionally.

Further, instead of using the pipe members 24 and 26, for example, as shown in phantom lines in the drawing, a plurality of spaces or chambers 50 can be provided in a stepped manner along the slope of the support portion 18. Each chamber 50 has an open surface that opens diagonally upward, and the open surface is covered with a net or mesh plate (not shown) that can prevent the aggregate 12 from flowing into each chamber 50. .

Each chamber 50 is connected to conduit 34 via a conduit (not shown). According to this example, compressed air can be blown out in each chamber 50, which is a space defined by a part of the bottle 14 and the aggregate 12, and the air expanded in each chamber 50 is discharged through the net or mesh. It passes through the plate and rises through the aggregate 12. As a result, the aggregate 12 is cooled, similar to when using the nozzle described above. The chamber 50 can be provided on the entire slope of the support part 18, for example.

Further, as shown in FIG. 2, the support part 18 is formed of a breathable material such as the net or mesh plate, and the conduit 34 is connected to the space 52 below the support part 18, that is, the bottle 1.
4 and the aggregate 12 are opened to a defined space, and the compressed air can be blown out in the space 52. The compressed air released into the space 52 passes through the support part 18 and reaches the aggregate 12.
The aggregate 12 is thereby cooled.

[Brief explanation of drawings]

FIG. 781 and FIG. 2 are schematic illustrations of an apparatus for carrying out the aggregate cooling method according to the present invention and a portion of another example apparatus, respectively. 10: Aggregate cooling device, 12: Aggregate, 14: Bin (aggregate storage container), 1: Air compressor, 2: Nozzle, 50.52: Chamber (space).

Claims (6)

[Claims] (1) A method of cooling aggregates by blowing compressed air into the aggregates. (2) A method for cooling aggregates, in which compressed air is jetted out in a space defined by a storage container containing aggregates and the aggregates. (3) Claim (3) wherein the compressed air is continuously ejected.
The method for cooling aggregate according to 1) or (2). (4) Claim (4) wherein the compressed air is ejected intermittently.
The method for cooling aggregate according to 1) or (2). (5) Claim (1) wherein the aggregate is pre-wetted with water.
) or the aggregate cooling method described in (2). (6) The method for cooling aggregate according to claim (1), (2) or (5), wherein the compressed air is cooled prior to being ejected.