JP2995213B2 - Agitator for cooling concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agitator for cooling concrete, which prevents the growth of concrete ice blocks adhering to the vicinity of an inlet of a tank due to scattering of concrete caused by ejection of liquefied gas.

[0002]

2. Description of the Related Art It is necessary to minimize the rise in temperature of concrete and mass concrete cast in the heat due to heat generated by hydration of cement. As a countermeasure for suppressing such a rise in the temperature of the concrete, it is known that a method of pouring cooling concrete obtained by cooling concrete that has not been solidified yet during kneading is effective. As one of the methods for producing the above-mentioned cooled concrete, a method of using a liquefied gas as a refrigerant and introducing the gas into the concrete being kneaded has been adopted.
According to this method, concrete can be cooled efficiently and at high speed.

FIG. 2 shows an example of a conventional biaxial concrete agitator used for the above-mentioned cooling method, which is an apparatus for producing the above-mentioned cooled concrete. That is, this biaxial concrete agitator
A double cylindrical tank 1 having a cocoon-shaped lower section, a plurality of stirring blades 3 provided with a central axis 2 parallel to the center of each cocoon of the tank 1, Spout 4
a, a cover 5 covering the periphery of the upper opening of the tank 1, a cover 6 for opening and closing the upper surface of the cover 5, and an exhaust pipe 7 protruding from an appropriate location on the upper part of the tank 1.
And a discharge gate (not shown) provided at the lower center of the tank 1.

[0004] Then, the upper surface of the cover 5 is opened, a concrete material is poured into the tank 1, and the upper surface of the cover 5 is closed.
By jetting a liquefied gas such as liquefied nitrogen gas into the tank 1 through the tank, the concrete can be kneaded while being cooled.

[0005]

However, in the cooling concrete agitator having this structure, the concrete is rapidly cooled by the liquefied gas ejected, and is cooled by the ejection pressure of the gas or the rotation of the rotor. The scattered concrete scatters in the upper space in the agitator, freezes as freezing substance A on the inner peripheral wall of the cover 5, grows as shown in the figure, closes a part of the opening in the tank 1, and after the stirring operation. There is a problem that the efficiency of the work for manufacturing the cooled concrete is reduced, for example, because it becomes an obstacle when the new concrete material is introduced into the tank 1 again.

Further, there have been various inconveniences such as the impact of each part in the tank when the grown ice blocks fall and fall, and the homogeneity of concrete is impaired due to the mixing of the ice blocks.

In order to prevent the growth of this type of frozen matter, conventionally, a method has been adopted in which a rubber heater is attached along the inner peripheral wall of the cover 5 and this is heated to sequentially thaw the frozen matter. However, since the rubber heater itself is made of a heat insulating material, it has poor thermal responsiveness and needs to be constantly heated, so that the power consumption is large and uneconomical. In addition, mortar, frost, and the like easily adhere to the surface of the rubber heater, and the impact resistance to collision is low.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an agitator for cooling concrete capable of reducing the power consumption of this type of thawing heater and improving safety. And

[0009]

In order to achieve the above object, an agitator for cooling concrete according to the present invention comprises a tank for stirring concrete, a rotating blade for stirring provided inside the tank, and a jetting tank for jetting into the tank. In a cooling concrete agitator comprising a liquefied gas supply nozzle having an outlet opened, a cover for covering a peripheral edge of an upper opening of the tank, and a lid for opening and closing an upper surface of the cover, a rubber heater is provided on an inner peripheral wall of the cover. And the surface of the rubber heater is covered with a ceramic plate.

[0010]

In the above construction, the frozen matter adheres to the surface of the ceramic which is the inner wall surface of the cover. Since the ceramic surface has lubricity and good heat conductivity, the temperature rises instantaneously by heating the rubber heater. As a result, the frozen matter is melted, peeled off the surface of the ceramic, falls, and mixes with the concrete.

[0011] The rubber heater is protected by the ceramic, and there is no fear of electric leakage due to collision of mortar or frozen matter.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a biaxial agitator according to this embodiment. The same parts as those in the conventional example are denoted by the same reference numerals, and only different parts will be described using different reference numerals. Further, in this embodiment, a case in which a biaxial type is adopted as the agitator will be described, but the present invention is not limited to such an example, and for example, a single-axis type agitator and other types of agitators may be used. Can be easily applied.

The agitator in the figure has a double cylindrical tank 1 having a cocoon-shaped cross section at the bottom, as in the conventional example.
A plurality of rotary blades 3 for stirring provided at the center of each cocoon of the tank 1 in parallel with a central axis 2, a nozzle 4 having an outlet 4a opened in the tank 1, and an upper opening of the tank 1 A cover 5 for covering the periphery of the cover 5 and a cover 6 for opening and closing the upper surface of the cover 5; Have.

Rubber heaters 10 are attached to the inner peripheral walls on both sides of the cover 5, and a ceramic plate 12 is fixed on the surface of the rubber heater 10 to cover the surface of the rubber heater 10.

The rubber heater 10 has a large number of heating wires 10b embedded in a rubber plate 10a as shown in an enlarged view of a part of FIG. 1. The heating is performed by passing a current through the heating wire 10b. Then, the entire rubber plate 10a is heated.

The heating wire 10b is intermittently heated by an external power turned on and off by a thermostat or a timer (not shown).

The heat transfer coefficient of the ceramic plate 12 is small, and when heat is transmitted from the heating wire 10b side, the entire surface thereof is instantaneously and uniformly heated. The exposed surface is top-glued and the like to make it smooth.

In the above configuration, when the liquefied gas is supplied through the nozzle 4 while stirring the concrete, the concrete is rapidly cooled, and thereby, the inner peripheral wall inside the cover 5 which is a free space where the rotor 3 does not interfere. The frozen matter adheres to the surface of a certain ceramic plate 12, but since the ceramic plate 12 is instantaneously heated in response to the heating of the heating wire 10b, the frozen matter does not grow without growing according to the heating cycle of the heating wire 10b. The adhering surface melts and falls from the surface of the ceramic plate 12 and is mixed with the concrete. Therefore, the impact given to each part due to the drop of the grown ice block, and the resulting unevenness in quality are prevented beforehand.

[0019]

As described above in detail, in the agitator for cooling concrete according to the present invention, the ceramic surface has lubricity and has good heat conductivity, so that the temperature rises instantaneously by heating the rubber heater. In addition, since the frozen matter melts without growing and peels off from the surface of the ceramic and mixes with the concrete, the operation of supplying, stirring and discharging the concrete can be sequentially and continuously repeated without being hindered by the frozen matter. In addition, it is possible to eliminate various problems such as the impact of ice blocks on each part of the agitator due to the growth of frozen matter and uneven quality.

Further, according to the present invention, the rubber heater is protected by the ceramic, there is no fear of electric leakage due to the collision of mortar or icy matter, and the heat consumption is fast, so that the power consumption can be reduced. Further, since there is no fear of an accident such as electric leakage due to the heater, safety can be improved.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing the entirety and a main part of an agitator for cooling concrete according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional agitator for cooling concrete and a defect thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank 2 Center axis 3 Stirring rotor 4 Nozzle 5 Cover 6 Lid 10 Rubber heater 10a Rubber plate 10b Heating wire 12 Ceramic plate

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Matsushima 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Obayashi Corporation Tokyo head office (56) References JP-A-3-5631 (JP, A) 2-115410 (JP, U)

Claims (1)

(57) [Claims] 1. A concrete stirring tank, a stirring rotor provided inside the tank, a liquefied gas supply nozzle having an ejection port opened in the tank, and a peripheral edge of an upper opening of the tank. A cooling concrete agitator having a cover that covers the cover and a cover that can open and close the upper surface of the cover, wherein a rubber heater is attached to an inner peripheral wall of the cover,
An agitator for cooling concrete, wherein the surface of the rubber heater is covered with a ceramic plate.