JPH0349855Y2 - - Google Patents

Description

[Detailed description of the invention] <<Industrial Application Field>> This invention relates to an agitator for cooling concrete that is used to properly finish the construction of hot concrete or mass concrete.

<<Prior Art>> When concrete is manufactured in hot weather, the mixing temperature becomes high, the unit amount of water required to obtain the same consistency increases, and the unit amount of cement required to achieve the same water-cement ratio also increases. In addition, the slump of concrete during hot weather during transport is greater. The unit water volume and cement volume must be further increased. Not only is this uneconomical, but
It also increases the temperature rise due to the heat generated by the cement, and increases drying shrinkage, making it more likely to cause defects such as clutches. Furthermore, since it hardens quickly, the time allowed for pouring is shortened, making construction difficult.

Furthermore, in mass concrete, concrete is a poor conductor of heat, and as it hardens and heats up, the internal temperature rises, increasing the temperature difference between the inside and outside surfaces, and surface clutches are likely to occur.
On the other hand, when concrete is restrained from the outside, the shrinkage caused by the temperature drop after hardening is also restrained.
Large tensile stresses occur.

For these reasons, hot concrete and mass concrete must be constructed while keeping the temperature of the concrete sufficiently low.

Conventionally, in order to keep the mixing temperature of concrete low, methods such as cooling cement, aggregate, water, etc., or using crushed ice in the mixing water (this is called pre-cooling) were used. ).

Another method was to install a cooling pipe in advance at the place where concrete is to be poured, and cool the concrete by passing cold water through the cooling pipe during concrete pouring to suppress the temperature rise caused by the hydration reaction. cooling).

[Problems that the invention aims to solve] Methods for cooling materials such as cement, aggregate, and water have low cooling effects despite the large scale of cooling equipment, and quality control is also difficult. The method of using crushed ice also requires large-scale ice-making equipment, and it is difficult to appropriately control the temperature and moisture content of the concrete.

Conventionally, the above-mentioned precooling has been carried out in concrete plants because it requires large-scale equipment. Therefore, when transporting concrete using a truck mixer to a concrete placement site far from the plant,
Even if it is cooled at the plant stage, the temperature of the concrete will rise at the pouring site.

Furthermore, the above-mentioned pipe cooling not only requires large-scale cooling equipment and water passage equipment, but also makes the installation work extremely complicated. Furthermore, there were problems such as the cooling pipe being susceptible to corrosion and the problem that the initial heat generation of the concrete could not be effectively suppressed due to the time lag between the cooling start time and the heat generation state of the concrete.

This idea was devised in view of the conventional problems mentioned above, and its purpose was to receive and temporarily store concrete transported to the pouring site by truck mixers, etc., and to prevent material separation of the concrete. To provide an agitator for cooling concrete, which has a simple structure that can efficiently cool concrete in a short time, and can reliably inject liquefied gas.

<Means for Solving the Problems> In order to achieve the above-mentioned purpose, the present invention includes a temporary storage container having an inlet and an outlet for concrete, and the separation of materials by stirring the concrete in this container. A concrete cooling agitator is provided with an agitation mechanism for preventing the liquefaction of the liquefied gas, and a nozzle mechanism for spouting liquefied gas from a storage container into the container to cool the concrete inside the container, The nozzle mechanism is formed in a double structure having a hollow part filled with vaporized gas, and the nozzle mechanism includes a tapered hole whose diameter expands outward, a valve body attached to the tapered hole, and a hollow part that is filled with vaporized gas. It is characterized by having an electric heater disposed near the.

<<Operation>> Prepare the above agitator and liquefied gas storage container at the concrete placement site. When the truck mixer arrives from the plant, the transported concrete is placed in the container through the receiving port and stored in the container until pouring. During storage, the stirring mechanism is activated to prevent separation of concrete materials. At the same time, liquefied gas is ejected from the nozzle mechanism to cool the concrete inside. The cooled concrete is taken out from the outlet and poured. At this time, the vaporized liquefied gas fills the hollow part of the container. In addition, the nozzle mechanism that injects liquefied gas is equipped with an electric heater, so
Freezing of the taper hole through which liquefied gas is injected can be prevented.

<<Embodiment>> FIG. 1 shows a horizontal agitator which is a first embodiment of this invention. Cylindrical container 1 on the trolley
0 (drum) is mounted horizontally. Container 10
A concrete receiving port 12 is provided at one end, and a concrete discharge port 14 is provided at the other end. Although not shown, each of the intake port 12 and the discharge port 14 is provided with a shutter plate that opens and closes the opening.

A hollow shaft 16, which also serves as the nozzle device, is rotatably supported at the center of the container 10, and a spiral stirring blade 18 is attached around the hollow shaft 16. The hollow shaft 16 is rotationally driven in a predetermined direction by a drive unit 20 (including a motor and gears) attached to the outer wall of the end of the container 10. 22 indicates the concrete contained in the container 10, and this concrete 22 is
8 rotates together with the central shaft 16 to agitate the concrete material so as not to cause separation, and force acts to push the concrete from the receiving port 12 side to the discharge port 14 side.

A large number of nozzle holes 24 (nozzle mechanism) are formed in the hollow shaft 16. Further, the end of the hollow shaft 16 communicates with a hose 28 via a rotary pipe joint 26. Although not shown, this hose 28 is connected to a liquid nitrogen storage container. When liquid nitrogen is pumped from the storage container through the hose 28 to the hollow shaft 16, the liquid nitrogen is ejected from the nozzle hole 24 and rapidly cools the surrounding concrete 22 with its latent and sensible heat.

FIG. 2 shows the detailed structure of the nozzle hole 24 portion. As shown in the figure, the nozzle hole 24 is a tapered hole whose diameter increases toward the outside, and a valve body 24a is attached to this tapered hole. This valve body 24a functions as a check valve, and the hollow shaft 1
Liquid nitrogen from inside 6 is spouted to the outside,
This prevents mortar in the container 10 from entering the hollow shaft 16. Further, an electric heater 24b is disposed inside the shaft 16 near the nozzle hole 24, and the heater 24b is configured to heat the periphery of the nozzle hole 24. This is nozzle hole 24
This is to prevent the area near the nozzle hole 24 from being rapidly cooled and freezing when liquid nitrogen is ejected from the nozzle hole 24.

A safety valve 30 is provided at the top of the container 10, and when the pressure inside the container 10 increases to a certain degree, the safety valve 30 opens to release the gas inside.

As is clear from the above explanation, the concrete transported by the truck mixer is received into the container 10 from the receiving port 12, and the drive unit 20 is used to move the concrete into the hollow shaft 1.
6. While rotating the stirring blade 18, liquid nitrogen is force-fed from the storage container to the hollow shaft 16, and liquid nitrogen is ejected from the nozzle hole 24. This allows the concrete to cool rapidly while preventing concrete separation. At the time of pouring, the shutter of the discharge port 14 is opened to discharge the concrete.

By the way, it is desirable that the container 10 be made of a material with good heat insulation properties. Further, the container 10 has a hollow double structure, and is configured to fill the hollow portion with vaporized nitrogen. Freshly vaporized nitrogen has a very low temperature, so by filling and circulating the hollow part of the container 10, the cooling efficiency of the concrete 22 can be greatly increased.

FIG. 3 shows a vertical agitator which is a second embodiment of this invention. In this second embodiment, a cylindrical container 10 is arranged vertically, and has an inlet 12 at its upper part and an outlet 14 at its lower part.

A hollow shaft 16 is horizontally supported near the center of the container 10 and is rotationally driven by a drive unit 20. A plurality of independent plate-shaped stirring blades 32 are radially attached around the hollow shaft 16. The support shafts of these stirring blades 32 are also hollow, and the hollow shaft 1
It communicates with 6. A nozzle hole 24 having a structure similar to that shown in FIG. 2 is formed on the support shaft. These nozzle holes 24 communicate with the hollow shaft 16, the rotary joint 26, and the hose 28.
is connected to a liquid nitrogen storage container (not shown).

The nozzle hole 24 is provided on the back side with respect to the rotating direction of the stirring blade 32. The stirring blade 32 is rotationally driven by the hollow shaft 16 and stirs the concrete 22, and liquid nitrogen is jetted out from the nozzle hole 24 on the back side of the stirring blade 32 to evenly cool the concrete 22.

In this embodiment as well, the container 10 has a double structure.

By the way, in both the first and second embodiments described above, liquid nitrogen is supplied through the hollow shaft 16 which is the rotation shaft of the stirring blade 18 or 32, but the present invention is not limited to this. Regardless of whether the container is horizontal or vertical, a nozzle pipe with numerous nozzle holes is constructed in the upper space of the container, and liquid nitrogen is directed from this nozzle pipe toward the concrete inside the container in a shower shape. It may also be configured to eject.

Additionally, when cooling concrete, if a sensor is installed to detect the temperature of the concrete in the container and the amount of liquefied gas ejected is adjusted according to the temperature of the concrete, insufficient cooling or overcooling of the concrete can be prevented. .

<<Effects of the invention>> As explained in detail above, according to the concrete cooling agitator according to this invention, pouring can be easily achieved by simply adding a simple configuration to the temporary storage agitator used at the pouring site. Since the concrete immediately before being cooled can be extremely efficiently cooled to the desired temperature in a short time, it is possible to finish hot concrete and mass concrete construction with good results.

In addition, in this invention, the container in which concrete is primarily stored has a double structure with a hollow part,
The hollow space is filled with naturalized liquefied gas. Not only can the temperature of the cooled concrete be kept at a low temperature, but also the cooling efficiency can be increased.

Furthermore, in this invention, the nozzle mechanism has a reverse valve structure, which prevents concrete from entering the nozzle mechanism, and the nozzle mechanism has an electric heater, which prevents the injection of liquefied gas. In some cases, freezing of the tapered hole can also be prevented.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the horizontal concrete cooling agitator according to this invention, Figure 2 is a detailed view of the nozzle hole 24 part in Figure 1, and Figure 3 is a vertical concrete cooling agitator according to this invention. FIG. 10... Container, 12... Inlet, 14... Outlet, 16... Hollow shaft, 18, 32... Stirring blade,
20... Drive unit, 22... Concrete,
24... Nozzle hole, 26... Rotary pipe joint, 28
……hose.

Claims (1)

[Scope of utility model registration request] A temporary storage container having a concrete reception port and a discharge port, a stirring mechanism for stirring the concrete in the container to prevent material separation, and a liquefied gas pumped from the storage container into the container. A concrete cooling agitator is provided with a nozzle mechanism for cooling the concrete inside, the container being formed in a double structure having a hollow portion filled with the vaporized liquefied gas,
The nozzle mechanism is for concrete cooling, characterized in that it has a tapered hole whose diameter expands outward, a valve body attached to the tapered hole, and an electric heater arranged near the tapered hole. Agitator.