JPS6371309A - Manufacture of low-temperature concrete, etc. - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a method for producing low-temperature concrete, etc., which can produce excellent low-temperature concrete and low-temperature mortar in an efficiently cooled state, particularly in hot weather. This is a technology that can be suitably used for manufacturing concrete, etc., and concrete with a large mass.

(b) Conventional technology It is known that when producing low-temperature concrete, etc., effective cooling can be achieved without any change in the composition by using liquid nitrogen. Low-temperature concrete, etc., in which the finished concrete, etc. is placed in a container, and then the tip of a liquid nitrogen introduction pipe is inserted into the container, and extremely low-temperature liquid nitrogen is directly sprayed onto the concrete, etc. to lower the temperature. There has been a manufacturing method for a long time.

According to this method, part of the liquid nitrogen spouted from the tip of the liquid nitrogen introduction tube evaporates, lowering the surrounding temperature, and at the same time absorbs heat from the air inside the container using the gas specific heat of the gasified nitrogen. Since the atmosphere inside the container is cooled, concrete etc. are rapidly cooled. In other words, concrete, etc. has a low boiling point (boiling point knee 196°C) and a large latent heat of vaporization (latent heat of vaporization: 48 Kcal/Kg) due to the properties of liquid nitrogen and the large specific heat of gas: 0.248 K.
cal/Kg'C) Based on the properties of nitrogen gas, it will be rapidly cooled. Therefore, there are advantages such as being able to arbitrarily set the temperature of concrete, etc. within a wide range.

(c) Problems to be solved by the invention However, in the method for manufacturing low-temperature concrete, etc., described above,
Since extremely low temperature liquid nitrogen is directly sprayed onto the finished concrete, there are disadvantages in that the sprayed liquid nitrogen rapidly cools and freezes only specific areas, or it evaporates all at once and expands hundreds of times. , the heat utilization efficiency is low due to the disadvantage that there is a large amount of nitrogen gas that is dispersed into the outside air at a low temperature without cooling the concrete, etc., so when bringing the concrete, etc. to be manufactured below the desired temperature, The disadvantage is that the amount of liquid nitrogen used is large, making it uneconomical.

In view of the above-mentioned problems, the present invention aims to provide a method for producing low-temperature concrete, etc., which makes it possible to quickly and accurately cool the concrete, etc. to be produced to a desired temperature range using a small amount of liquid nitrogen. be.

(d) Means to solve the problem The means taken by the present invention will be explained with reference to FIGS. 1 and 2.

Concrete or mortar is manufactured in the container 1 as follows.

That is, a material such as concrete is stored in the container 1, and then water is atomized in the container 1 and liquid nitrogen is vaporized to produce low-temperature concrete or the like.

(e) The working water is made fine in the container 1, and its surface area increases significantly. On the other hand, the temperature inside the container 1 drops significantly due to the vaporization of liquid nitrogen. As a result, the finely divided water undergoes rapid heat exchange within the container 1 (4), and its temperature drops within a short period of time. This low-temperature water serves as a medium to cool the material A, such as concrete.

On the other hand, the material A, such as concrete, is further cooled directly from the inside with cryogenic liquid nitrogen or the like in the container l.

Therefore, the extremely low temperature nitrogen gas produced by vaporizing liquid nitrogen contributes to the cooling of material A such as concrete more than before, and then is dispersed to the outside of the container.

When the material A, such as concrete, is cooled in this way, the concrete or the like to be manufactured will inevitably be in a cooled state and at a low temperature.

(F) Embodiments Hereinafter, specific embodiments of the present invention will be described based on the drawings.

1 and 2 show a mixer which is an example of a device for carrying out the present invention, and l is a container in which two stirring devices 2 and 2 are arranged in parallel, a kneading tank section 3 and a cover section. It consists of 4. 5 is a cement supply chute disposed at the center of the top surface of the cover portion 4, and 6 and 7 are a gravel supply chute and a sand supply chute disposed on each side of the cement supply chute 5. All chutes 5, 6, and 7 penetrate the top surface of the cover part 4, and each tip is connected to the stirring device 2 in the container.
2 facing upwards.

8 is the main pipe for supplying water, and there is a water stop valve 9 in the middle.
is interposed, and a branch pipe 10 is connected from the upstream side of the water stop valve 9.
is branched out. This branch pipe 10 branches into two on the downstream side of a water stop valve 9a interposed in the middle,
Each tip communicates with water injection nozzles 11 disposed below the top surface of the cover portion 4. Water injection nozzle 11/11
The jetting direction is directed downward, and the jetting jet is formed so as to atomize water into a mist or raindrop shape and spray the water so as to enlarge its surface.

12 is a main pipe for passing liquid nitrogen (with a pressure of around 9 kg/cut), and it branches into two on the downstream side of the valve 13, and each tip is connected to a respective water injection nozzle 1.
Each nitrogen injection nozzle 14, 1 arranged near 1, 11
It communicates with 4. This injection direction intersects with the injection direction of the water injection nozzle 11, and the water further atomized by liquid nitrogen is spread as uniformly as possible within the kneading tank section 3.

Although not shown in the drawings, a gas vent is provided as necessary to release the nitrogen gas expanded within the container 1 to the outside air.

By using the above device, the present invention is implemented as follows.

First, material A such as concrete is stored in the container 1 through the chutes 5, 6, and 7. In this case, there is no problem in answering whether the material A for concrete or the like is only aggregate such as gravel and/or sand, or if it is aggregate with cement, water, and additives added. However, when mixing water with material A such as concrete, it is important to set the amount of water to be less than the planned mixing amount.

Next, the water in the container 1 is atomized and the liquid nitrogen is vaporized. To do this, the water stop valve 9a is opened and water is injected from the water injection nozzles 11. 13 and open the nitrogen injection nozzle 14.
・Cryogenic liquid nitrogen will be injected from 14.

In this case, the liquid nitrogen will vigorously mix with the water in the form of mist or raindrops. As a result, the water is promoted to become finer and is exposed to an atmosphere whose temperature is extremely lowered. In other words, the water has an increased surface area and is surrounded by an atmosphere with a significant temperature difference. Therefore, rapid heat exchange takes place in this atmosphere, and the water is cooled to an extremely low temperature in a short period of time, becoming partially ice-like.

When the above action is performed above material A such as concrete, cryogenic water and/or thin ice falls onto material A such as concrete that has been stirred in advance by stirring device 2. It falls onto the material A, such as concrete, which is being stirred by the stirring devices 2, 2, and is uniformly mixed or permeated into the material A, such as concrete. For this reason, the material A such as concrete is not only cooled by contacting the nitrogen gas in the container 1, but also is strongly kneaded by the stirring device 2. It is also cooled from within by cooled water and/or thin ice.

On the other hand, the cryogenic nitrogen gas, etc. that formed the atmosphere with a significant temperature difference inside the container 1 absorbs the heat of the finely divided water, so the temperature is higher than before.
In other words, the particles are sequentially dispersed outside the container 1 while the atmospheric temperature inside the container 1 is further lowered.

Then, predetermined amounts of water and liquid nitrogen are injected from the water injection nozzles 11, 11 and the liquid nitrogen injection nozzles 14, 14.

This allows material A such as concrete to be heated to an arbitrary temperature.

Note that the final amount of water contained in concrete, etc. is the sum of the amount of water injected from the water injection nozzles 11 and 2 of the water separately supplied to material A, such as concrete, so this amount of water is The amount of water must be adjusted to match the planned mix water amount for concrete, etc.

FIG. 3 shows a part of another concrete mixer for carrying out the present invention, and the difference from the previous device is that water and liquid nitrogen are directly supplied inside material A such as concrete, The injection nozzles 11a and lla and the nitrogen injection nozzles 14a and 14a are arranged close to the bottom of the kneading tank section 3.

According to this, since water is atomized and liquid nitrogen is vaporized in material A such as concrete, it is expected that the low heat accompanying vaporization of liquid nitrogen can be used more effectively.

Further, FIG. 4 shows a nozzle 15 with a double pipe structure in which a water injection nozzle llb is provided outside the nitrogen injection nozzle 14b, and such a nozzle can be used in place of the water injection nozzle 11 and the nitrogen injection nozzle 14 described above. You can also use This nozzle 15 has the advantage of being able to vaporize liquid nitrogen and atomize water at the same time with a single nozzle. It is also possible to use other media.

Further, in order to improve water jetting, it is preferable to provide a pressurizing device for increasing water pressure in the middle of the water piping.

(G) Effects of the Invention According to the present invention as described above, it is not simply spraying only liquid nitrogen onto finished concrete, etc., but the water is expanded to 1 m in the container and the liquid nitrogen is vaporized. , it is possible to effectively utilize the low heat of a large amount of nitrogen gas, which conventionally would have been dispersed into the outside air at a low temperature, and it is possible to efficiently cool the material A such as concrete. Therefore, it becomes possible to quickly and accurately cool the concrete, etc. to be manufactured to a desired temperature range using a small amount of liquid nitrogen, which has the advantage of making concrete manufacturing economical.

Further, since the material A such as concrete during the manufacturing process is cooled with liquid nitrogen or the like, there is an advantage that it is possible to freely avoid partially frozen state of the finished concrete.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a mixer which is an example of a device for implementing the present invention, and FIG. 2 is a side view of the mixer.
FIG. 3 is a partially cutaway front view of another mixer, and FIG. 4 is a sectional view showing a nozzle having a double tube structure. (Symbol) ■...Container 2...Agitator 11, lla, ILb...'Water injection nozzle 14.14a
, 14b...Nitrogen injection nozzle A...Materials such as concrete

Claims (1)

[Claims] 1. When producing concrete or mortar in a container,
A method for producing low-temperature concrete, etc., characterized by storing a material such as concrete in a container, and then atomizing water and vaporizing liquid nitrogen in the container. 2. A method for producing low-temperature concrete or the like according to claim 1, characterized in that water is atomized and liquid nitrogen is vaporized at least inside a material such as concrete made of aggregate. 3. A method for producing low-temperature concrete or the like according to claim 1, characterized in that water is atomized and liquid nitrogen is vaporized at least above a material such as concrete made of aggregate. 4. A method for producing low-temperature concrete, etc., according to claim 1, characterized in that finely divided water is frozen with liquid nitrogen.