JP2595823B2 - Cooling method for concrete aggregate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cooling an aggregate for concrete, wherein the aggregate is kneaded with cement in a pre-cooling method while the aggregate is cooled to 0.degree.

[0002]

2. Description of the Related Art The pre-cooling method is a method of pre-cooling a concrete material to lower the temperature at which the concrete is poured. Generally, the aggregate occupies most of the volume of the concrete and has a large cooling effect. After being cooled in advance, the mixture is kneaded to form a concrete having a kneading temperature of about 10 ° C.

As a method of cooling the aggregate, generally, a method of cooling by circulating cold air or cold water in the aggregate bin, or a method of spraying cold water during transportation is generally used, but has the following problems. .

[0004]

That is, if cold air or cold water is used, the temperature of the aggregate cannot be reduced to 0 ° C. or less, and if the transportation time and the mixing time are long, the once cooled aggregate will heat up. However, there is a disadvantage that the cooling capacity is reduced. As a countermeasure, it has been considered to circulate a refrigerant with extremely high cooling efficiency such as liquefied nitrogen gas inside the aggregate bin and to further lower the temperature, but since a cylinder and other supply equipment are required, When a new cooling facility is newly installed, the equipment cost is high, and the refrigerant once heat-exchanged cannot be reused and is consumed, resulting in a high running cost.

An object of the present invention is to provide a method of cooling an aggregate for concrete that can utilize existing equipment and can be mixed with concrete while cooling the aggregate to a lower temperature.

[0006]

In order to achieve the above object, the present invention provides a method of cooling concrete aggregate before kneading, wherein an antifreeze is used as cooling water and the temperature is reduced to 0 to -15 ° C. Setting, and immersing the aggregate in a tank containing the cooling water.

[0007]

The antifreeze used for cooling the aggregate does not freeze even when cooled to -15 ° C, and can be cooled using ordinary cooling equipment. The antifreeze liquid cooled to this temperature is stored in a tank, and the aggregate can be cooled to 0 ° C. or lower by immersing the aggregate in the tank. The cooled antifreeze is collected and reused.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an entire configuration of a concrete manufacturing plant to which the method of the present invention is applied. In the figure, the manufacturing plant is provided with an aggregate bin 1a containing fine aggregate S and an aggregate bin 1b containing coarse aggregate G. A first belt conveyor 2 is provided below each of the aggregate bins 1a and 1b.

At the end of the first belt conveyor 2,
A switching chute 3 is provided, and a second and third extending in a direction away from each other are provided at an outlet of the switching chute 2.
Belt conveyors 4 and 5 are installed. At the end side of the third belt conveyor 5, a batcher plant 6 for kneading is provided. A fourth belt conveyor 8 is provided at the end of the second belt conveyor 4 for distributing and supplying the aggregates S and G to a plurality of cooling tanks 7 installed below the second belt conveyor 4.

An antifreeze liquid W is supplied to each cooling tank 7 from a cold water storage tank 9 via a pump P. The antifreeze W is cooled by the chiller 10 and its temperature is set to 0 ° C. to −15 ° C. A drain screen 11 with a belt conveyor is disposed below the cooling tank 7. Aggregates S and G drained by the screen 11 are passed through fifth and sixth belt conveyors 12 and 13. It is transferred to an intermediate position of the third belt conveyor 5.

On the other hand, the used antifreeze solution W separated by the draining sieve 11 is sent to the sedimentation tank 14 to remove the contaminating sand, and the supernatant of the sedimentation tank 14 is sent to the chiller 10. Supplied and reused. The cold water storage tank 9 is provided with a temperature sensor, and the drive control of the water cooler 10 is performed in accordance with the value indicated by the sensor, so that the temperature of the antifreeze W in the cold water storage tank 9 is constantly 0 to- It is kept at 15 ° C. In addition, the chemical to be added to the antifreeze W is, for example, ethylene glycol, propylene glycol, or the like.

In the above configuration, the type of aggregate, the mixing ratio of cement, mixing water and the like, and the production amount are determined. When the plant is operated, the designated aggregate bin 1
A predetermined amount of each of the aggregates S and G is sequentially supplied onto the first belt conveyor 2 via the measuring units a and 1b. In addition, the pump P is driven to supply the antifreeze liquid W in the cold water storage tank 9 to the cooling tank 7, and the aggregates S and G are put into the cooling tank 7 via the second and fourth belt conveyors 4, 8. And immersed in the antifreeze solution W. Thereby, each of the aggregates S and G is cooled to 0 ° C. or less.

After that, the antifreeze liquid W is removed by the draining screen 11, and the aggregates S and G are transferred to the third belt conveyor 5 via the fifth and sixth belt conveyors 12 and 13, and the batcher It is put into the plant 6. While the cooling process of each of the aggregates S and G is being performed, the cement is put into the batcher plant 6 and the aggregates S and G are cooled.
Kneaded with G and water.

The temperature of the concrete after kneading is 5
The cooling temperature of the antifreeze liquid W required for cooling the aggregates S and G is determined according to the outside air temperature, the kneading time, the cement and the water temperature when this temperature is set.

[0015]

As has been described in detail in the above embodiments, in the method for cooling concrete aggregate according to the present invention, the antifreeze used for cooling the aggregate freezes even when cooled to -15 ° C. Therefore, the concrete can be cooled to an extremely low temperature by using ordinary cooling equipment, and the temperature of the finished concrete can be maintained at a desired low temperature. Also,
By using the antifreeze, the cooling equipment of a conventional concrete manufacturing plant can be diverted, and the used antifreeze can be collected and reused, so that there are advantages such as low equipment cost and running cost.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a concrete manufacturing plant to which an aggregate cooling method of the present invention is applied.

[Explanation of symbols]

 1a, 1b Aggregate bin 7 Cooling tank S, G Aggregate W Antifreeze

Claims (1)

(57) [Claims] 1. A method of cooling an aggregate for concrete before kneading, wherein an antifreeze is used as cooling water, the temperature is set at 0 to -15 ° C., and the aggregate is placed in a tank containing the cooling water. A method for cooling aggregate for concrete, characterized by immersing water.