JPH0440167B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> This invention provides a method for mixing ready-mixed concrete.
The present invention relates to a method for cooling concrete materials.

<Conventional technology> Generally, ready-mixed concrete is made of cement whose main components are limestone, sintered powder of granular soil, and fly ash.
It is made by mixing aggregates such as pebbles and sand and kneading the mixture uniformly with water, but during this kneading, the cement and water react and a reaction heat called heat of hydration is generated.

This increase in reaction heat causes cracks in concrete and a decrease in strength, so in order to suppress the increase in reaction heat, methods for cooling concrete materials have been proposed, such as the one shown in Figure 2. (Japanese Patent Application Laid-Open No. 61-220806).

It is arranged between a cement container 51 and a cement measuring device 53, an aggregate container 54 and an aggregate measuring device 56, a mixing water supply source 57 and a mixing water measuring device 59, and a mixing water supply source 57 and a water measuring device 59. An interposed water tank 60 for water cooling, a refrigerant supply vessel 64 that supplies liquefied refrigerant gas (liquid nitrogen) 65 into the water tank 60, and a refrigerant used for cooling the kneading water 58 and released from the water tank 60. The gas 65a is transferred to the aggregate container 5.
4 and a concrete mixer 70, when mixing a specified amount of cement 52 and a specified amount of aggregate 55 with a specified amount of mixing water 58, a refrigerant gas provided in a water tank 60 is provided. While blowing out bubbles of liquefied refrigerant gas 65 from the gas nozzle 61 to cool the water in the water tank 60 in advance,
The aggregate 5 is made of refrigerant gas 65a used for cooling the water.
This is a method in which 5 is cooled.

<<Problems to be solved by the invention>> Generally, the strength of concrete is determined by the amount of cement 5 charged into the concrete mixer 70 during mixing.
For example, the ideal amount of water is said to be 20 to 25% of the amount of cement. If the moisture content exceeds the specified amount, the strength of the concrete will decrease accordingly, so each measuring device 53, 56, 59 is designed to accurately measure the amount of water.

However, according to the above conventional example, the water 58 in the water tank 60 is discharged from the refrigerant gas 65 from the refrigerant gas nozzle 61.
It is cooled by blowing out air bubbles. Therefore, the refrigerant gas 65a released from the water tank 60
contains a large amount of moisture such as mist-like moisture or water vapor, and when the aggregate 55 is cooled with the refrigerant gas 65a, a large amount of water droplets adhere to the aggregate 55. Moreover, the amount of water droplets attached to the aggregate is not constant depending on whether the aggregate 55 is pebbles or gravel. For this reason, in the above-mentioned conventional method, the proportion of water varies depending on the content of the aggregate, and moreover, the proportion of water tends to increase, which has the disadvantage that the strength of the concrete decreases accordingly. Furthermore, the above-mentioned Japanese Patent Application Laid-Open No. 61-220806 proposes a method in which bubbles of refrigerant gas are released into a heat medium liquid such as glycol, and kneading water is indirectly cooled through this heat medium liquid. There is. According to this method, although the refrigerant gas does not come into contact with the water for kneading, it passes through the heat medium liquid instead of the water for kneading, so that the vapor or mist of the heat medium liquid is mixed into the vaporized refrigerant gas. As a result, droplets of the heat transfer fluid adhere to the aggregate, resulting in the same difficulties as in the conventional method described above. Moreover, since the droplets of the heat transfer liquid become organic impurities and mix into the concrete, there is a possibility that problems in construction such as a decrease in strength may occur.

<<Means for Solving the Problems>> The present invention has been made to solve the above problems, and is configured as follows.

In other words, when mixing a specified amount of cement and a specified amount of aggregate with a specified amount of mixing water, the water is cooled in advance with liquefied refrigerant gas, and the bones are mixed with vaporized refrigerant gas used to cool the water. In a method for cooling concrete materials, the mixing water is cooled by passing liquefied refrigerant gas through the gas pipes of a refrigerant gas heat exchange water cooler piped into the mixing water, and the gas flow in the gas pipes is cooled. By communicating the outlet with the gas inlet of the aggregate container through a refrigerant gas conduit and introducing the vaporized refrigerant gas into the aggregate container,
This method is characterized in that aggregates are cooled with a refrigerant gas that does not contain moisture or a liquid component of a heat transfer liquid (hereinafter simply referred to as moisture).

<<Operation>> In the present invention, the kneading water is cooled by passing liquefied refrigerant gas into the gas pipe of the heat exchange type water cooler provided between the kneading water supply source and the kneading water meter, and Since the gas outlet is communicated with the inside of the aggregate container, even when using the refrigerant gas used to cool the mixing water, the aggregate can be cooled with the refrigerant gas that does not contain water. This makes it possible to maintain a stable water supply ratio at all times.

<<Example>> Fig. 1 is a schematic diagram of a concrete mixing apparatus showing an example of the present method invention.

This concrete mixing device includes a cement container 1 containing cement 2, a cement measuring device 3 disposed below the cement container 1, an aggregate container 4 containing aggregate 5, and an aggregate measuring device 6 disposed below the cement container 1. , a kneading water supply source 7 and a water meter 9, a refrigerant gas heat exchange type water cooler 10 interposed between the kneading water supply source 7 and the water meter 9, and a liquefied refrigerant gas ( A liquefied refrigerant gas container 14 that supplies liquid nitrogen) 15, and a refrigerant gas conduit that communicates the gas outlet of the water cooler 10 with the gas inlet at the bottom of the aggregate container and introduces the vaporized refrigerant gas 15a into the aggregate container 4. 17, and a concrete mixer 20 disposed below each measuring device 3, 6, 9, the concrete mixer 20 mixes a specified amount of cement 2, a specified amount of aggregate 5, and a specified amount of mixing water 8. 20 for kneading.

The water cooler 10 is, as schematically shown in FIG.
The kneading water 8 in the storage tank 11 is cooled by absorbing vaporization heat from the kneading water 8 in the storage tank 11 when it flows through the gas pipe 12 .

The refrigerant gas 15a that has absorbed the heat of vaporization passes through the refrigerant gas conduit 17 into the aggregate container 4 through a gas inlet formed at the bottom of the aggregate container 4, and cools the aggregates 5.

In addition, as shown by the imaginary line in FIG. 1, a refrigerant gas conduit 18 for introducing the liquefied refrigerant gas 15 into the concrete mixer 20 may be provided to cool the inside of the concrete mixer 20 as required. In this case, the refrigerant gas 15a cools the aggregate 5 and the concrete material in the concrete mixer 20.
is released into the atmosphere.

In the above embodiment, liquid nitrogen is used in consideration of harmlessness, non-flammability, cost, etc. However, liquid oxygen, liquefied methane gas, liquefied carbon dioxide gas, etc. can be used as long as the purpose of the present invention can be achieved. It is also possible to use liquefied refrigerant gas.

<<Effects of the Invention>> According to the present invention, even when aggregates are cooled with vaporized refrigerant gas used to cool kneading water,
Since the refrigerant gas does not contain water, there is no risk of unnecessary water droplets adhering to the aggregate. As a result, even if the content of the aggregate changes, the water supply ratio will not change or the water supply amount will not exceed the specified amount, which will not reduce the strength of the concrete. Moreover, since the water for kneading is cooled without using a heat transfer liquid, heat can be exchanged directly inside and outside the gas pipe, resulting in efficient cooling.
The refrigerant gas that cools the aggregates is not mixed with the heat transfer liquid, which is an organic impurity, and there is no adverse effect on the construction or quality of concrete.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a concrete mixing apparatus showing an embodiment of the present invention, and FIG. 2 is a diagram corresponding to FIG. 1 showing a conventional example. 1... Cement container, 2... Cement, 3... Cement measuring device, 4... Aggregate container, 5... Aggregate, 6... Aggregate measuring device, 7... Kneading water supply source, 8... Water for kneading, 9... Water measuring device , 10... Refrigerant gas heat exchange type water cooler, 14...
Liquefied refrigerant gas container, 15... Liquefied refrigerant gas (liquid nitrogen), 15a... Refrigerant gas, 17... Refrigerant gas conduit,
20...Concrete mixer.

Claims (1)

[Scope of Claims] 1. When kneading a specified amount of cement and a specified amount of aggregate with a specified amount of mixing water, the water is cooled in advance with liquefied refrigerant gas, and the water is used for cooling and vaporized. In a concrete material cooling method in which aggregates are cooled with refrigerant gas, the mixing water is cooled by passing liquefied refrigerant gas through the gas pipe of a refrigerant gas heat exchange water cooler piped into the mixing water, and the above-mentioned By communicating the gas outlet of the gas pipe with the gas inlet of the aggregate container via a refrigerant gas conduit and introducing the vaporized refrigerant gas into the aggregate container, the aggregate is cooled with refrigerant gas that does not contain moisture. A method for cooling concrete materials characterized by: