JP3680124B2 - Raw concrete sticking prevention method in a stirrer and raw concrete sticking prevention apparatus for carrying out the method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for preventing sticking of raw concrete in a stirrer and a sticking prevention device for carrying out the method.
[0002]
[Prior art]
Until now, the raw concrete remaining in the base of the stirring plate and the like after being discharged from the stirrer has been washed in the raw concrete stirrer.
In the case of an agitator car, in the summer, the temperature inside the stirrer rises to about 30-40 ° C or more under the hot weather, and this temperature shortens the curing time of the raw concrete and decreases the concrete strength. Will occur. Further, the temperature in the agitator after the discharge rises rapidly, and the residual raw concrete solidifies rapidly in a short time.
In addition, due to the high temperature of the stirrer itself, even before the raw concrete is released, the raw concrete accumulates in the recesses in the stirrer, and the solidification and fixation of the concrete proceeds without sufficient stirring.
For this reason, even if water is rapidly ejected immediately after the raw concrete is discharged, the residual raw concrete once solidified cannot be washed off.
[0003]
Accordingly, the solidified residual concrete that cannot be easily peeled off enters the stirrer and is removed by a hammer or the like.
In the case of batchers, water washing is usually performed immediately after the release of raw concrete. However, the amount of fixing increases no matter how water washing is performed, and in practice at least once a week. To some extent I had to do the lifting work.
Whether it is an agitator car or a batcher, it is very dangerous to carry out the suspension work in the stirrer, and it is necessary to rotate the stirrer without knowing that the worker is still in the stirrer. There is an actual situation that the death accident that ends up is not refused every year.
As a safety measure, a safety device using a sensor for confirming the presence of a person as a stirrer has been proposed. However, since the cleaning work itself performed by the workers is not lost, complete safety measures have been impossible.
[0004]
Also, in the case of an agitator car, the time for unloading from the start of raw concrete production is determined to be within 90 minutes (JIS standard), and if it exceeds 90 minutes, the quality deteriorates due to high temperatures. Acceptance may be refused by the customer as outside.
[0005]
Separately, there is a cooling device that uses liquefied gas for the purpose of preventing the strengthening and cracking of the concrete after placement and maintaining the quality of the raw concrete, and temporarily cooling the raw concrete itself. Proposed.
There are many cooling devices for directly cooling the raw concrete before transportation, and some cooling devices for cooling at the installation site have been proposed.
Among them, an apparatus (Japanese Patent Laid-Open No. Sho 61-229507) that is mounted on an agitator car (concrete mixer car) and injects liquefied gas into the raw concrete has been proposed.
However, liquefied gas is very expensive and suitable for temporary cooling, but it is not suitable for continuous cooling during transportation because a large amount of liquefied gas is required.
[0006]
In addition, it has also been proposed to mix and use crushed ice in the raw concrete to cool the raw concrete. There is a drawback that the strength is lowered.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and by delaying the curing time, it prevents sticking of the raw concrete, facilitating the water washing operation, and makes it unnecessary for the worker to enter the stirrer. The present invention provides a raw concrete sticking prevention method in a stirrer and a raw concrete sticking prevention apparatus for carrying out the method.
In addition, the present invention provides a method and apparatus for maintaining the quality for a long time and preventing the decrease in the strength of the concrete.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention continuously feeds cold air into the agitator 3 of the raw concrete immediately before or immediately after the loading of the raw concrete until immediately before the in-machine cleaning. The concrete temperature is maintained in the set low temperature range to delay the curing time of the raw concrete, and after discharging the raw concrete, water is injected into the stirrer 3 to leave the in-machine residual raw concrete in an uncured state. This is a method for preventing sticking of raw concrete in a stirrer, characterized in that it is washed away.
[0009]
Further, the base end portion 2a of the air duct 2 is connected to the cold air blower 1, and the front end portion 2b is made to face the upper space in the agitator 3 of the raw concrete. The apparatus for preventing sticking of raw concrete in a stirrer for carrying out the above method characterized in that the concrete temperature can be maintained in a set low temperature range.
[0010]
Furthermore, in the apparatus having the above-described configuration, the agitator 3 is an agitator wheel 4.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings.
[0012]
The method for preventing the ready-mixed concrete in the stirrer 3 of the present invention continues to send cold air into the ready-mixed concrete stirrer 3 immediately before or after loading the ready-mixed concrete until immediately before the cleaning of the ready-mixed concrete. Maintaining the set low temperature range (the low temperature range of the present invention covers the range of about 1 ° C. to about 15 ° C.) delays the hardening time of the ready-mixed concrete and injects water into the stirrer 3 after the ready-mixed concrete is discharged. It is characterized in that the ready-mixed residual concrete is washed away before the ready-mixed concrete is hardened.
[0013]
Even in the case where the start time of the cleaning operation in the stirrer is delayed, it is necessary to keep sending the cold air until immediately before the cleaning without stopping the blowing so that the residual raw concrete is not solidified. Once the raw concrete is solidified, the adhesion strength to the inner wall of the stirrer becomes stronger, so it is meaningless to cool it after solidification.
[0014]
Next, as shown in FIG. 4, an apparatus for carrying out the above method connects the base end 2a of the cool air blowing duct 2 to the cool air blower 1, and the tip 2b of the raw concrete agitator 3 A temperature sensor (not shown) that detects the temperature in the stirrer 3 is attached to the tip 2b of the top 2b. When the temperature sensor detects that the temperature of the raw concrete in the stirrer 3 has become equal to or higher than the preset temperature, the cooler 1 is controlled to operate, and the temperature is lowered to the preset temperature and the raw concrete in the stirrer 3 is always controlled. -The temperature of the product can be maintained within a set low temperature range (about 1 ° C to about 15 ° C).
[0015]
For example, when the outside air temperature becomes 28 ° C. and the temperature inside the stirrer 3 rises and the raw concrete temperature reaches about 15 ° C., the cool air fan 1 is operated and the temperature is lowered by about 3 ° C. to about 12 ° C. Below.
In addition, when the outside air temperature is about 12 ° C, the temperature inside the stirrer 3 rises above that and becomes higher than the outside air temperature. If left as it is, the outside air temperature is about 15 ° C or higher. Even if it is lower than this, the cold air blower 1 is operated.
In summer, the outdoor temperature during the day is always higher than about 15 ° C, and in winter, the temperature is often lower.
For this reason, the temperature control by the temperature sensor is not used, and the set cooling temperature of the cool air blower 1 is mechanically set to -10 ° C during the period from May to October under the condition of the insulation coating. However, the period from November to April may be set to -5 ° C. Also, the set value can be set more finely than this.
[0016]
In order to cool the entire inner wall of the stirrer 3, the cold air flows downward, so that it is necessary to face the upper space in the stirrer 3 and open the air duct 2.
In the case of an agitator wheel (Japanese Patent Laid-Open No. 61-229507) that is press-fitted into a conventional raw concrete, bubbles are mixed in the raw concrete and the strength of the concrete is reduced. Therefore, it should not be opened to the middle or bottom of the stirrer 3.
[0017]
The cold air machine 1 to be used can be operated using a household power source, an automobile engine, or the like as a power source. In this case, continuous cooling is possible as long as there is fuel. In addition, the cost of generating cold air is extremely low compared to submerged gas.
[0018]
In particular, in the agitator vehicle 4 in which the stirrer 3 is mounted on an automobile, it can be continuously cooled at a low cost for a long time by using an automobile engine as a power source.
And even if it takes a long time and is transported over a long distance, there is an advantage that deterioration in the quality of concrete can be prevented by maintaining it at a low temperature.
[0019]
In summer, the temperature in the stirrer 3 may rise to 40 ° C. or more when exposed to direct sunlight. However, as shown in FIGS. 2 and 3, if the stirrer 3 portion is covered with the heat insulating material 5, the temperature rise can be effectively prevented by itself, and the load and energy consumption on the motor of the cool air fan 1 can be reduced. Can be reduced.
[0020]
Since the temperature is low in winter, it is not necessary to cover the heat insulating material 5. For this reason, it makes sense to make the heat insulating material 5 removable by a stirrer.
In addition, as shown in FIG. 5, the insulating material 5 made of foamed polystyrene is bonded to a vinyl sheet 7 and a hook, an attached tape 8a or the like is attached to the end thereof. It is also possible to adopt a body winding type in which the fixing means 8 is provided and wound around the stirrer 3.
The outside of the stirrer 3 is not covered with the bottom face not exposed to sunlight, and the heat insulating effect can be obtained by covering the top face and the side face exposed to direct sunlight with the heat insulating material 5.
[0021]
Further, as shown in FIG. 6, the air duct 2 can also be improved in energy efficiency by being covered with a heat insulating material 9 such as foamed polystyrene in order to prevent temperature rise.
Reference numeral 10 in FIGS. 1 and 2 denotes a water tank that stores water used for cleaning or the like in the stirrer 3.
[0022]
【The invention's effect】
The present invention is as described above, and the cool air is continuously fed into the agitator of the raw concrete to maintain the temperature inside the apparatus at about 15 ° C. or less, thereby greatly delaying the curing time of the raw concrete.
By delaying the curing time, the raw concrete is prevented from sticking, and the residual raw concrete is easily washed away by a simple water washing operation. Therefore, the work inside the stirrer is completely unnecessary.
In addition, since the temperature is maintained at an appropriate temperature, deterioration of the raw concrete quality can be prevented. And long-distance delivery is possible without causing quality degradation, and live concrete can be placed under high temperatures in summer.
[0023]
In other countries, such as the United States, where there is no raw concrete base, raw concrete raw materials, ie, raw sand, cement, and water can be delivered to produce raw concrete locally due to the difficulty of long-distance delivery. However, it takes a lot of time and money to construct a live concrete manufacturing facility for that purpose, which is a large cost burden.
According to the present invention, the curing time of raw concrete is greatly delayed by cold air, and long-distance delivery from a small number of bases at a long distance from such a site is possible. No construction is required and a significant cost reduction can be realized.
[Brief description of the drawings]
FIG. 1 is a side view of an agitator vehicle according to the present invention.
FIG. 2 is a side view showing a state in which an agitator wheel stirrer is covered with a heat insulating material.
3 is a cross-sectional end view taken along line AA of the stirrer portion in FIG. 2. FIG.
FIG. 4 is a schematic front view of a batcher according to the present invention.
FIG. 5 is a circular end view of a body-wrap type coated insulating material.
FIG. 6 is a sectional end view showing a state in which the air duct is covered with a heat insulating material.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cold air blower 2 Air duct 2a Opening part of air duct 3 Raw concrete stirrer 4 Agitator wheel 5 Heat insulating material 6 Removable bolt 7 Vinyl sheet 8 Fixing means 8a Adhesive tape 9 Heat insulating material 10 Water tank

Claims (1)

The base end (2a) of the air duct (2) is connected to the cold air blower (1), and the front end (2b) faces the upper space in the agitator (3) of the ready-mixed concrete, and the front end (2b) ) Is equipped with a temperature sensor for detecting the temperature in the agitator (3), and the temperature of the ready-mixed concrete in the agitator (3) is controlled by controlling the temperature sensor so that the cold air fan (1) is operated. about 1 ℃ fresh concrete anti-sticking device in stirring machine, characterized in that to allow maintained at the set low temperature range of to 15 ° C..

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