JPH0698619B2 - Concrete material cooling system - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for cooling concrete materials such as gravel, sand and cement.

“Conventional technology” When constructing so-called mass concrete structures such as dams, bridge piers, and nuclear reactor facilities, concrete is prone to cracking due to temperature stress caused by the heat of hydration of cement, and concrete cracks are prevented. Has become an important issue in quality control.

As a means for preventing this cracking, a pre-cooling method is known in which the kneading temperature of concrete is lowered. In this method, concrete constituent materials such as cement, water, sand, and gravel are cooled in advance, and the cooled materials are mixed to obtain low-temperature concrete.

In the conventional pre-cooling method, it is general to use cold water, ice, or cold air as a cooling medium for cooling the above materials, and a refrigerator is used as a cold heat source for lowering the temperature of these cooling media. Is common.

[Problems to be Solved by the Invention] By the way, in the conventional pre-cooling method using the cold water, ice, or cold air as the cooling medium as described above, the temperature of the cooling medium itself can be lowered only to about 0 ° C. is there.
Therefore, the temperature of each concrete material can be lowered only by about 5 to 10 deg, and it cannot be made sufficiently low, and there is a problem that it takes a long time to cool it.

For this reason, it has been considered to cool the material directly and rapidly by using an ultra-low temperature liquefied gas such as liquid nitrogen, but in this case, a large amount of expensive liquefied gas is consumed. Moreover, it is difficult to freely control the cooling temperature, and it has not been widely used.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an apparatus that can obtain a sufficiently low temperature in a short time and can cool a material at low cost.

"Means for Solving Problems" The cooling device of the present invention is a device for cooling concrete materials such as gravel, sand, and cement, and has an input port provided in the upper portion and an outlet port provided in the lower portion. A silo for storing the concrete material therein, a blower for sending air into the silo through a blower pipe, and collecting and circulating the sent air from the upper part of the silo through a return pipe, and the blower. Provided in the middle of the pipe,
An air cooling device that blows a liquefied gas such as liquid nitrogen to the air sent to the silo to directly cool the air by the liquefied gas to form cooling air, and the air cooling device is provided at a front stage of the air cooling device. And a dehumidifying device provided in the middle of the blower pipe to dehumidify the air supplied to the air cooling device. Inside the silo, the blower pipe is connected to and fed by the blower pipe. A blow-out pipe for blowing out cooling air over the whole area of the concrete material stored in the silo is installed, and a large number of openings for blowing out the cooling air are provided on the peripheral surface of the blow-out pipe in a substantially uniform manner. It is characterized by being formed over the entire length.

It is preferable that the charging port provided on the upper portion of the silo is provided with a lid which is made of an elastic material such as hard rubber and has a flat plate shape, and a plurality of slits are radially formed at the center thereof. .

[Embodiment] An embodiment in which the present invention is applied to the cooling of gravel will be described below with reference to FIGS. 1 to 7.

FIG. 1 is a system diagram showing a schematic configuration of the cooling device of this embodiment. First, the configuration of the cooling device will be described.

This cooling device mainly includes a silo 1 for storing gravel, an air blowing device 2 for blowing cooling air into the silo 1, an air cooling device 3 for producing cooling air, and a dehumidifying device 4 for removing water in the air. It is a component.

The blower device 2 includes a blower 5, blower tubes 6a, 6b, 6c, and blower tubes 21,2.
2, 30 (see FIGS. 2 and 3) and a return pipe 34 (described later), and blows air by the blower 5 through the dehumidifier 4 and the air cooler 3 to the lower part of the silo 1, The cooling air sent in is collected from the upper part of the silo 1 through the return pipe 34 and circulated. Note that reference numeral 7
Is an outside air intake for taking in outside air as needed. In addition, a damper 8 for adjusting the air volume is provided in the middle of the air duct 6b.
Is provided.

The dehumidifying device 4 is provided between the air blowing pipes 6a and 6b of the air blowing device 2.
Are arranged. The dehumidifier 4 is for obtaining the dry air by cooling the air sent by the blower pipe 6a to a temperature below the dew point to remove the moisture in the air to dehumidify it. The dehumidification by the dehumidifier 4 is such that when a large amount of water is present in the air when the air is cooled by the air cooling device 3 to be described later, the water deprives the heat of solidification and the air temperature changes. This is done in order to prevent the phenomenon of not being sufficiently lowered.

The air cooling device 3 is provided downstream of the dehumidifying device 4. The air cooling device 3 includes a cold air tank 14 and a liquid nitrogen discharge pipe 1 whose cross section is enlarged from the blower pipes 6b and 6c.
5, consisting of a cylinder 16 of liquid nitrogen and discharging the liquid nitrogen into the air sent from the blower pipe 6b to the cold air tank 14 to directly cool the air by the heat of vaporization of this liquid nitrogen. is there.

The cooling air cooled by the air cooling device 3 is blown into the silo 1 by the blower pipe 6c. The silo 1 stores gravel 17 inside, and as shown in FIG. 2, has a loading port in which a lid 32 described later is mounted and a hopper portion 18 is formed in the bottom portion as shown in FIG. An outlet 19 for gravel 17 is provided on the bottom surface. The gravel 17 is loaded by the shooter 20 from above the silo 1. In addition, it is desirable to attach a heat insulating material to the silo 1 so as to enhance the cold insulation effect.

The silo 1 is connected to the blower pipe 6c and is connected to the silo 1
Blower tubes 21, 22 and 30 for sending cooling air are installed therein. That is, around the outside of the bottom of the silo 1, there is provided an annular blower pipe 21 as shown in FIG.
A slit pipe (blowing pipe) 24 that penetrates the side wall of the silo 1 and extends upward in the silo 1 is connected to the blower pipe 21 via a valve 25. As shown in FIG. 4, the slit tube 24 has a large number of slits (openings) 26 formed on its circumferential surface over substantially the entire length thereof, and the cooling air is sent into the silo 1 through the slits 26. It contacts the gravel 17 stored in 1 and cools it. These slits 26 have different sizes over several steps (three steps in this embodiment) such that the slits 26 are small in the lower portion of the slit tube 24 and large in the upper portion thereof, and are evenly distributed over the entire length of the slit tube 24. Cooling air is discharged. Further, the blower pipe 22 is branched from the blower pipe 6c through a valve 27, and a slit pipe (blowing pipe) 28 similar to the slit pipe 24 is arranged in the blower pipe 22 at the center of the silo 1. (See FIG. 3). Further, as shown in FIG. 5, a ring-shaped slit tube (blowing tube) 23 connected to the blower pipe 6c through a valve 29 and a blower pipe 30 is provided at the bottom of the silo 1. There is. A large number of slits (openings) 31 are formed in the slit tube 23. The slits 31 are small in the vicinity of the connection point with the blower tube 30 and become large as the distance increases along the flow direction of the cooling air. ing. Cooling air is also sent into the silo 1 from the slit 31 of the slit tube 23 to cool the gravel 17.

In addition, a lid as shown in FIG.
32 is installed. The lid 32 is formed of an elastic material such as hard rubber into a circular flat plate shape corresponding to the cross-sectional shape of the silo 1, and a plurality of slits (8 slits in this embodiment) are radially formed in the central portion thereof. 33 are formed. When the gravel 17 is put into the silo 1 by the shooter 20 as shown in FIG.
The center part is lowered by the weight of 17 and opens, and after the completion of charging, it returns to its original position due to its elasticity and closes the opening part.

The return pipe 34 is provided between the silo 1 and the blower 2. The return pipe 34 is used to circulate and use the cooling air that has cooled the gravel 17 stored in the silo 1, one end of which is connected to the upper part of the silo 1 and the other end thereof is the air cooling. It is connected to the inlet side of the blower 5 located at the front stage of the device 3.

The configuration of this cooling device has been described above.
A cooling method by this device will be described. First, a predetermined amount of gravel 17 is put into the silo 1. And this gravel
The amount of air blown by the damper 8 and the amount of liquid nitrogen discharged from the cylinder 16 are adjusted according to the set value of the cooling temperature of 17. Here, the temperature of the liquid nitrogen discharged from the cylinder 16 is an extremely low temperature of about minus 196 ° C. (at 1 atm),
By mixing this with air, the temperature of the air is set to, for example, about -30 ° C to -40 ° C.
Furthermore, the amount of dehumidification by the dehumidification device 4 is adjusted. It is desirable that the relative humidity of the dry air obtained by the dehumidifier 4 be about 20 to 30% or less. Then, when the blower 5 is operated, the air taken in from the outside air intake 7 is dehumidified and then cooled, and the cooling air is discharged into the gravel 17 stored in the silo 1, and the gravel 17 Will be contacted with and cooled. At this time, the slit pipes 24 connected to the blower pipes 21 are arranged on the outer peripheral portion of the silo 1, and the slit pipes 24 extend vertically in the silo 1 and further to the blower pipes 22. The connected slit tube 28 is arranged in the central portion of the silo 1 and
Since 28 extends vertically in the silo 1, the cooling air passes through the entire area of the gravel 17 to cool the gravel 17 uniformly and efficiently. The cooling air that has cooled the gravel 17 is recovered through the return pipe 34, returned to the blower 5, cooled through the dehumidifier 4 and cooled by the air cooling device 3, and again inside the silo 1 from the blower pipe 6c. Will be circulated to. When the gravel 17 is cooled to the set temperature by continuing the circulation of the cooling air for a predetermined period of time, the operation is stopped, the gravel 17 is discharged from the outlet 19 at the bottom of the silo 1, and new gravel is charged. Repeat the procedure.

As described above, in the cooling method using this cooling device, the temperature of the gravel is lowered by a maximum of about 20 degrees because the air is sufficiently cooled by liquid nitrogen and the gravel is cooled by this low temperature cooling air. Is possible,
Therefore, low-temperature gravel, which cannot be obtained by the conventional means using cold water or cold air, can be obtained in a short time. In addition, compared to the case of cooling by directly spraying liquefied gas directly onto the gravel, the consumption of liquid nitrogen can be reduced, operating costs can be significantly reduced, and cooling can be performed by adjusting the discharge amount of this liquid nitrogen. The temperature can be easily set. Also, the slit tube 2 provided in the silo 1
The cooling air is blown out through the entire area of the gravel 17 through 3,24,28, and the cooling air is forcibly recovered from the upper part of the silo 1 through the return pipe 34. Will flow upward from the bottom, so that the cooling air will pass over the entire area of the gravel 17 without creating a short circuit, and the gravel 17 will be in a floating / flowing state due to the upstream side of the cooling air blowing. Therefore, the particles of the gravel 17 (or other concrete material such as sand or cement) will not freeze and harden each other, and the individual particles such as the gravel 17 in the silo 1 Cooling air is surely brought into contact with all of them to uniformly and effectively cool the whole.

Further, since this device is designed to dehumidify before cooling the air, it is possible to prevent the decrease of the air temperature from being hindered by the moisture in the air, and it is possible to enhance the cooling efficiency. Further, since the silo 1 is provided with the lid 32 made of an elastic material, the cooling air blown into the silo 1 does not unnecessarily flow out, the cooling effect of the silo 1 is enhanced, and the lid is provided when gravel is thrown in. You can save the trouble of opening and closing 32 each time.

Although liquid nitrogen is used in the cooling device of the above embodiment, the present invention is not limited to this, and other liquefied gas such as liquid helium may of course be used.

Furthermore, the present invention can be applied not only to cooling gravel but also to sand and cement, and the forms of slit pipes (blow-out pipes) 24, 28, 23 arranged in the silo 1 are Of course, it may be appropriately changed depending on the type and the required cooling temperature.

"Effects of the Invention" As described in detail above, the cooling device of the present invention has the following excellent effects.

An air cooling device that directly cools the air with a liquefied gas is provided, and the cooling air obtained by this is used to cool the concrete material, so that the concrete material can be cooled to a sufficiently low temperature in a short time with a simple device. Moreover, the consumption of the liquefied gas can be reduced, and the cooling temperature can be freely set, so that the concrete material can be efficiently cooled at low cost.

Since a dehumidifying device is provided in the preceding stage of the air cooling device to cool the air after dehumidifying it by liquefied gas such as liquid nitrogen, it is possible that the cooled air contains a large amount of water. Absent. Therefore, when the air is cooled, the moisture hardly takes away the heat of solidification, so that the temperature of the air can be sufficiently lowered in a short time by a small amount of the liquefied gas, and the liquefaction can be performed. It is also advantageous in terms of cost by suppressing the gas consumption.

Since the cooling air that has cooled the concrete material is collected from the silo through the return pipe and is circulated and introduced again into the silo by the liquefied gas, the cooling heat loss of the cooling air is almost eliminated. In other words, the cooling air cooled by the liquefied gas is lower in temperature than the outside air even after the concrete material is once cooled, so that by collecting this low-temperature cooling air and cooling it to a predetermined temperature, the consumption of the liquefied gas is reduced. The amount and the air cooling time can be reduced, and the air cooling efficiency can be further improved.

Since the blowing pipe is installed in the silo, the cooling air is blown out through the blowing pipe over the whole area of the concrete material in the silo, and the cooling air is forcibly recovered from the upper part of the silo, Cooling air blow-up does not occur in the silo and a short circuit of cooling air does not occur. Therefore, ensure that cooling air is in contact with the entire concrete material to cool the entire concrete material uniformly and efficiently. You can

If a flat lid made of elastic material with radial slits is provided at the silo inlet, the cooling effect of the silo can be enhanced and cooling efficiency can be further improved, and at the time of concrete material input. You can save the trouble of opening and closing the lid each time.

[Brief description of drawings]

1 to 7 are views showing an embodiment of the present invention. FIG. 1 is a system diagram showing an overall schematic configuration of a cooling device of this embodiment, FIG. 2 is a vertical sectional view of a silo, and FIGS. 3 to 5 show a shape of a blower pipe for feeding cooling air into the silo. FIG. 3 is a plan view, FIG. 4 is an enlarged elevation view of a slit tube, FIG. 5 is a plan view, FIG. 6 is a plan view showing the shape of a silo lid, and FIG. It is an elevation sectional view explaining an operation of a lid. 1 ... silo, 2 ... air blower, 3 ... air cooler,
4 ... Dehumidifier, 5 ... Blower, 6a, 6b, 6c, 21,22,30 ...
… Blower tube, 17 …… gravel (concrete material), 19 …… outlet, 23,24,28 …… slit tube (blowing tube), 26,31…
… Slit (opening), 32 …… Lid, 33 …… Slit, 34…
… Return pipe.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Nagura, Kenji Nagura, 2-16-1, Kyobashi, Chuo-ku, Tokyo Within Shimizu Construction Co., Ltd. (56) References Japanese Patent Publication No. 29-75 (JP, B1) 29-6947 (JP, Y1) Showa 59-7679 (JP, Y2)

Claims (2)

[Claims] 1. A device for cooling concrete material such as gravel, sand and cement, the silo having an inlet at the top and an outlet at the bottom and storing the concrete material therein. A blower for sending air into the silo through a blower pipe, and collecting the air from the upper part of the silo through a return pipe to circulate it; and an air provided in the blower pipe and fed into the silo. An air cooling device for directly cooling the air with the liquefied gas by blowing a liquefied gas such as liquid nitrogen to produce cooling air; and an air cooling device located in the front stage of the air cooling device in the middle of the blower pipe. A dehumidifying device for dehumidifying the air supplied to the air cooling device, wherein the silo is connected to the blower pipe by the blower pipe. A blow-out pipe is provided for blowing out the cooled air taken in over the entire area of the concrete material stored in the silo, and a large number of openings for blowing out the cooling air are provided on the peripheral surface of the blow-out pipe. A cooling device for concrete material, characterized in that it is formed over almost the entire length of the blow-out pipe. 2. A lid having a flat plate shape made of an elastic material such as hard rubber, and a plurality of radial slits formed at the center of the insertion opening provided at the upper portion of the silo. The cooling device for the concrete material according to claim 1, wherein the cooling device is provided.