JP2595822B2 - 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, a method of using cooling water or ice water as the kneading water for the concrete, and a method of charging liquid nitrogen during kneading. In general, the aggregate occupies most of the volume of the concrete and has a large cooling effect. Therefore, the aggregate is supplied to the kneading position in a state of being cooled in advance, and the concrete having a temperature of about 10 ° C. is obtained.

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, in the present invention, an antifreeze is used as the cooling water, and the water temperature is set at 0 to -15 ° C.

[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 sprinkled on the aggregate through a water spraying facility, and the aggregate can be cooled to 0 ° C. or less according to the amount of heat. After watering, the 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 a concrete manufacturing plant to which the method of the present invention is applied. A plurality of aggregate bins 1 containing aggregates G, and a first belt conveyor having a starting end arranged below the aggregate bins 1 are shown. 2, a second belt conveyor 4 connected to the end of the first belt conveyor 2 via a dewatering sieve 3, a chute 5 having an opening disposed below the end of the second belt conveyor 4, Concrete mixer 6 connected to the lower part of chute 5 and chute 5
A water supply head 8 and a cement bottle 7 facing the opening.

A water sprinkling pipe 9 having a plurality of water sprinkling heads 9a is arranged in the upper part of the first belt conveyor 2 along the conveying direction. A tray 10 for collection is arranged below the first belt conveyor 2 and the dewatering sieve 3 along its longitudinal direction. These are connected to the cold water circulation equipment 11.

The chilled water circulating equipment 11 includes a water tank 12 for storing tap water B, a raw water tank 14 for storing recovered water A 'and separating slurry, an adjusting tank 15 for adjusting the concentration of antifreeze, and a cooling tank for storing cooled antifreeze. A water tank 16 and a refrigerator 18 are provided.

The water pipe 9 is provided with a pump P1 in a cold water tank 16.
And cooled antifreeze A is supplied.
The collecting tray 10 is connected to the raw water tank 14, and the tray 1
The water A 'recovered within 0 is circulated here. Raw water tank 14
Is supplied to the adjusting tank 15. In addition to the recovered water A ', water B in the water tank 12 is supplied to the adjusting tank 15 through the pump P2, and a predetermined amount of ethylene glycol or propylene glycol is supplied according to the detection result of the concentration detector 15a. And so on, and adjusted so that the antifreeze has a predetermined concentration.

The antifreeze A in the adjusting tank 15 and the cold water tank 16
Are supplied to the refrigerator 18 via the pumps P3 and P4, respectively, and the cooled antifreeze A circulates in the chilled water tank 16 in its entirety. The chilled water tank 16 is provided with a temperature sensor 16a, and the drive of the refrigerator 18 is controlled in accordance with the value indicated by the sensor 16a, so that the temperature of the antifreeze A in the chilled water tank 16 is constantly 0 to -15. ℃. Further, the water B in the water tank 12 is communicated with the water supply head 8 through the cold water producing machine 20 so that the water B cooled to a predetermined temperature can be supplied therefrom.

In the above configuration, the type of the aggregate G, the mixing ratio of the cement S, the water B for mixing and the like, and the production amount are determined. When the plant is operated, the measuring section 1a of the designated aggregate bin 1 is operated. A predetermined amount of aggregate G is sequentially discharged onto the first belt conveyor 2 through the first belt conveyor 2. Further, the pump P1 of the cold water tank 16 is driven to supply the cooled antifreeze to the sprinkling pipe 6, and the sprinkling head 9a is moved toward the aggregate G on the conveyor 2.
Antifreeze A cooled to below 0 ° C and below -15 ° C
Spray. As a result, the aggregate G is cooled to at least 0 ° C. or less while being transported on the belt conveyor 2. Then, after the antifreeze A adhered to the surface of the aggregate G is removed through the dewatering sieve 3, the aggregate G is transferred to the second belt conveyor 4, and is then put into the chute 5 from the end. At the same time, a predetermined amount of cement S is put into the chute 5 through the measuring portion 7a of the cement bottle 7, and a predetermined amount of water B cooled through the measuring portion 8a of the water supply head 8 is also put therein. Can be

On the other hand, the recovered water A 'which overflows from the first belt conveyor 2 or falls into the tray 10 through the dewatering sieve 3 is collected in the raw water tank 14, from which the adjusting tank 15 and the refrigerator 18 are again moved. After that, it is circulated to the cold water tank 16 and reused.

The concrete temperature after kneading is 5
The cooling temperature of the antifreeze A required for cooling the aggregate G, the amount of water spraying, etc. are determined according to the outside air temperature, the kneading time, the temperature of the cement S, and the temperature of the water B when this temperature is set. Is done.

[0016]

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 since the antifreeze can be collected and reused after watering, there are advantages such as low equipment cost and running cost.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aggregate bin (stock position) 2 First belt conveyor 3 Dewatering sieve 4 Second belt conveyor 5 Chute 6 Concrete mixer 7 Cement bin 8 Water supply head 9 Watering pipe 9a Watering head 10 Collection tray 11 Cold water circulation equipment G bone Material S Cement B Water A Antifreeze A 'Collected water

Claims (1)

(57) [Claims] 1. A method for discharging aggregates at a stock position onto a belt conveyor and cooling the aggregates by spraying cooling water on the aggregates while conveying the aggregates to a mixing position with cement. A method for cooling aggregate for concrete, characterized in that an antifreeze liquid is used as the cooling water, and a watering temperature is set at 0 to -15 ° C.