JPH078490B2 - Concrete mixer with cooling function - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a concrete mixer, and more particularly to a concrete mixer with a cooling function adapted to cool concrete being kneaded by utilizing a liquefied gas.

<< Conventional Technology >> When concrete is manufactured in the heat, the kneading temperature becomes high, the unit water amount for obtaining the same consistency increases, and the unit cement amount required for obtaining the same water-cement ratio also increases. In addition, the drop of slump during transportation becomes large, and the unit water amount and cement amount must be further increased. This is not only uneconomical, but also increases the temperature rise due to the heat generation of the cement and increases the drying shrinkage, which increases the possibility of causing defects such as cracks. Further, the curing is quickened, the time allowed for splicing is shortened, and the construction becomes difficult.

Also, in mass concrete, since the concrete is a poor conductor of heat, the internal temperature rises with heat generation during hardening, the temperature difference between the inside and the outside surface increases, and surface cracks easily occur. . When the concrete is restrained from the outside, the shrinkage caused by the temperature drop after hardening is restrained, and a large tensile stress is generated.

For these reasons, it is necessary to take some measures to reduce the temperature of kneading concrete for hot concrete and mass concrete.

Conventionally, in order to suppress the kneading temperature of concrete to a low level, methods such as cooling materials such as cement, aggregate and water, and using crushed ice for kneading water have been adopted.

<< Problems to be Solved by the Invention >> The method for cooling a concrete material requires a large-scale facility for cooling, and the facility cost and its operating cost are enormous. Moreover, the effect of lowering the temperature of the kneaded concrete is not sufficient only by cooling the material, and the quality control of the concrete is difficult. The method using crushed ice also requires a large-scale ice making feeder and is a costly method. Also, when using crushed ice, it is difficult to control the temperature and water content of concrete properly,
It is difficult to control the quality of concrete.

The present invention has been made in view of the background as described above, and an object thereof is to use a very simple liquefied gas as a cooling source so that the concrete can be effectively cooled to an appropriate temperature during kneading. To provide a concrete mixer with cooling function.

<< Means for Solving Problems >> The concrete mixer with a cooling function according to the present invention is
A drum-shaped mixer main body, a center base standing upright from the center of the bottom of the mixer main body, a rotary head rotatably supported by the center base, and a concrete mixer at the tip portion attached to the rotary head. In a concrete mixer comprising a plurality of arms having a blade for mixing, and an inlet for concrete material provided on the upper part of the mixer body, the concrete mixer further includes an internal pipe that rotates coaxially with the rotary head. An external pipe for feeding a liquefied gas that communicates with the internal pipe through a rotary joint, and a pipe that is in communication with the internal pipe through the pipe in the central base or in the rotary head and around the central base or the rotary head. And an injection nozzle that opens to the center, through the external pipe and the internal pipe The liquefied gas is sent to the over scan or a rotary head, it is characterized in that ejected toward the concrete during kneading from the injection nozzle of the surroundings.

<< Operation >> According to the present invention, the liquefied gas is drawn into the center of rotation through the external pipe and the internal pipe, and the liquefied gas is injected from the periphery of the center base or the rotary head to the surrounding concrete. The injected cooling gas cools the entire concrete uniformly and efficiently in association with the stirring action by the arm that is mounted on the rotary head and rotates coaxially.

<< Embodiment >> FIG. 1 shows a first embodiment of the present invention. 10 is a drum-shaped mixer main body, 12 is a leg provided at the bottom of the mixer main body, 14 is a cylindrical center base provided at the center of the bottom of the mixer main body 10, 16 is rotatably mounted on the center base 14. The rotary head is supported and rotationally driven by a built-in motor (not shown). A plurality of arms 20 are attached to the peripheral surface of the rotary head 16 via fixtures 18, each arm 20 is arranged facing downward, and a kneading blade 22 is fixed to the tip portion thereof. There is.

24 is an opening / closing gate as an inlet for concrete material provided at the top of the mixer body 10, and 26 and 28 are opening / closing gates 24
It is a pipe for introducing concrete material and water provided in the part. The material of the concrete 30 is charged into the mixer main body 10 through the charging pipes 26 and 28, and the rotary head 16 is rotated. When the rotary head 16 rotates, a large number of blades 22 of the arm 20 rotate around the bottom of the mixer body 10 in concentric circles, forcibly mixing the concrete 30. The above are the usual components of a concrete mixer.

In the concrete mixer according to the present invention, in order to introduce a liquefied gas (for example, liquid nitrogen or liquid carbon dioxide) into the mixer body 10, the external pipe 32 and the internal pipe 3
4, The rotary joint 36 is provided. The internal pipe 34 is disposed coaxially with the upper part of the rotary head 16, and the internal pipe 34 and the external pipe 32 are connected by a rotary joint 36.

The internal pipe 34 is a pipe arm inside the rotary head 16.
It communicates with 38. A plurality of pipe arms 38 are radially mounted on the upper portion of the outer peripheral surface of the rotary head 16, and a plurality of nozzle portions 40 are provided on the lower surface of the pipe arm 38. Reference numeral 42 is a safety valve attached to the upper surface of the mixer main body 10 and opens when the pressure in the mixer main body exceeds a certain level.

In the above configuration, the rotary head 16 is rotated to rotate the blade.
When the concrete 30 is mixed and mixed at 22, the external pipe 32 is connected to the liquefied gas storage container, and the liquefied gas is fed to this. The liquefied gas introduced is internal pipe 34, pipe arm 38.
It flows inside and jets downward from the nozzle portion 40. The pipe arm 38 is located above the concrete 30 being mixed and is rotating together with the rotating head 16. Since the liquefied gas is ejected from the pipe arm 38 toward the concrete 30 below, the concrete 30 can be evenly cooled to a considerably low temperature. The degree of cooling can be adjusted by appropriately controlling the ejection amount of the liquefied gas and the ejection and stopping of the liquefied gas. For example, the mixer body 10
A temperature sensor is provided near the bottom of the concrete 30 to control the degree of cooling while measuring the temperature of the concrete 30 and lower the concrete 30 to an optimum temperature. Note that when the inside of the mixer main body 10 has a high pressure to some extent due to the ejection of the liquefied gas, the safety valve 42 opens and releases the gas to the atmosphere.

FIG. 2 shows a second embodiment of the present invention. The same components as those in the first embodiment described above are designated by the same reference numerals,
A description of the same parts will be omitted. In this embodiment, the internal pipe 34 communicates with the pipe 46 shown by the dotted line, and is led from the rotary head 16 to the lower side of the center base 14. The nozzle portion 44 for ejecting the liquefied gas is
The liquefied gas introduced radially into the pipe 46 is blown into the concrete 30 from here.
In this way, since the nozzle portion 44 is arranged in the concrete 30 being mixed, the concrete 30
The cooling effect of is more direct.

In the second embodiment, the nozzle 44 is made of concrete.
Since it is buried in the nozzle 30, the portion near the nozzle portion 44 may be overcooled, and water or mortar may be frozen around the nozzle portion 44. To prevent this, the nozzle portion 44 is provided with an appropriate heating means. As a heating means, a thin heating medium circulation pipe is wound around the nozzle portion 44, and a high temperature liquid or gas is supplied to the circulation pipe. In FIG. 2, 32a
Is a liquefied gas pipe, and 32b is a pipe for supplying the heating medium.

FIG. 3 shows a third embodiment of the present invention. In this embodiment, the liquefied gas jet nozzle portion 48 is provided on the back side of the kneading blade 22 (the rear side in the rotational direction), and the nozzle portion 48 and the internal pipe 34 pass through the arm 20. It is connected by piping 50. According to this embodiment, on the back side of the rotating blade 22, the liquefied gas is transferred to the concrete 30
Since it is ejected toward, the cooling action of the liquefied gas can be spread evenly over the concrete 30.

<< Effects of the Invention >> As described in detail above, according to the present invention, the drum-shaped mixer main body, the center base standingly installed from the center of the bottom of the mixer main body, and the center base rotatably In a concrete mixer comprising a supported rotating head, a plurality of arms attached to the rotating head and having a blade for concrete mixing at a tip portion thereof, and a concrete material input port provided on an upper portion of the mixer body. Liquefied gas sent to the mixer through the external pipe and the internal pipe to the concrete being mixed, the injection nozzle provided around the center base or the rotary head through the pipe in the center base or the rotary head. Since it is jetted from, it is attached to the rotary head The liquefied gas can be evenly sprayed over the whole of the concrete being stirred, whereby the concrete being kneaded can be efficiently cooled.

[Brief description of drawings]

1, 2, and 3 are block diagrams of the first, second, and third embodiments of the present invention, respectively. 10 …… Mixer body, 16 …… Rotating head 20 …… Arm 22 …… Mixing blade 30 …… Concrete, 32 …… External piping 34 …… Internal piping, 36 …… Rotary joint 40,44,48 …… Nozzle part

Claims (6)

[Claims] 1. A drum-shaped mixer main body, a center base standing upright from the center of the bottom of the mixer main body, a rotary head rotatably supported by the center base, and attached to the rotary head. Multiple arms with blades for concrete mixing at the tip,
In a concrete mixer provided with a concrete material input port provided at an upper portion of the mixer body, the concrete mixer further communicates with the internal pipe coaxially rotating with the rotary head and the internal pipe via a rotary joint. An external pipe for feeding a liquefied gas, and an injection nozzle communicating with the internal pipe via the pipe in the center base or the rotary head and opening to the periphery of the center base or the rotary head, A concrete mixer with a cooling function, characterized in that a liquefied gas sent to a center base or a rotary head through pipes and internal pipes is ejected from the injection nozzles around these toward the concrete being mixed. 2. The concrete mixer with cooling function according to claim 1, wherein the nozzle portion is provided above the concrete being mixed. 3. The concrete mixer with cooling function according to claim 1, wherein the nozzle portion is provided so as to be located inside the concrete being mixed. 4. The concrete mixer with a cooling function according to claim 1, wherein the nozzle portion rotates together with a kneading blade. 5. The invention according to claim 1, wherein the nozzle portion is provided on the back side of the kneading blade.
Concrete mixer with cooling function according to the item. 6. The concrete mixer with cooling function according to claim 1, wherein a heating means for preventing freezing is added to the nozzle portion.