JPS6371310A - Mixer for 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) Field of Industrial Application The present invention relates to a mixer for low-temperature concrete, etc., which can produce excellent low-temperature concrete or low-temperature mortar in an efficiently cooled state.

(b) Prior Art Conventionally, there have been mixer trucks that pick up concrete, etc. from a mixer that kneads concrete or mortar materials to form concrete or mortar, and transport it to another location.

(c) Problems to be solved by the invention By the way, in order to deal with the problem of cracks caused by increased shrinkage of concrete, etc. in concrete, etc. in hot weather or in concrete with a large mass, concrete, etc. is cooled before pouring. It is necessary to put it in a state.

As one method, conventionally, the tip of a liquid nitrogen introduction pipe is inserted into the kneading container of the mixer truck to supply extremely low temperature liquid nitrogen.According to this method, liquid The cryogenic liquid nitrogen supplied from the tip of the nitrogen introduction tube evaporates and lowers the surrounding temperature, and at the same time, the gasified cryogenic nitrogen gas absorbs heat from the air inside the container and causes the temperature inside the container to decrease. Since the atmosphere is cooled, concrete etc. are rapidly cooled. In other words, concrete etc. have a low boiling point (boiling point knee 196℃)
And the latent heat of vaporization is large (latent heat of vaporization: 48Kcal/Kg
) and the gas specific heat is large (specific heat:
It is rapidly cooled based on the properties of nitrogen gas (0.248 Kcal/Kg'C). Therefore, there are advantages such as being able to arbitrarily set the temperature of concrete, etc. within a wide range.

However, when using the above method, the extremely low temperature nitrogen gas created by gasifying liquid nitrogen vaporizes and expands hundreds of times, so it is released into the outside air at a low temperature without cooling the concrete etc. The heat of liquid nitrogen is not fully utilized. Therefore, when bringing concrete or the like below a desired temperature, a large amount of liquid nitrogen is used, which is disadvantageous and uneconomical.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention seeks to provide a mixer that allows concrete to be manufactured to be cooled to a desired temperature range using a small amount of liquid nitrogen with a simple structure.

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

A liquid nitrogen injection nozzle 14 that injects liquid nitrogen into the inside of a kneading container 1 configured as follows using a conventional mixer as a front trap.
and a water spray nozzle 11 for spraying finely divided water inside the kneading container 1.

(e) The working water is made fine in the kneading vessel 1, and its surface area is significantly increased. On the other hand, the temperature of the atmosphere inside the kneading container 1 is lowered by cooling by vaporization of liquid nitrogen and cooling by extremely low temperature nitrogen gas produced by vaporization of liquid nitrogen. As a result, the finely divided water rapidly exchanges heat with the nitrogen gas, etc. in the kneading container 1, and the temperature drops in a short time. Then, this low-temperature water becomes a cooling medium, and the material A, such as concrete, is cooled.

On the other hand, the material A such as concrete is also directly cooled by the cryogenic liquid nitrogen in the kneading container 1 in parallel with the above cooling.

When the material A, such as concrete, is cooled in this way, the finished concrete, etc. will inevitably be in a cooled state, and by adjusting the amount of liquid nitrogen, etc., the desired temperature range can be achieved.

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

1 and 2 show an example of a mixer according to the present invention. Reference numeral 1 denotes a kneading container in which two stirring devices 2 are arranged side by side, and is composed of a kneading chamber part 3 and a cover part 4. 5 is a cement supply chute disposed at the center of the top surface of the cover section 4, and 6 and 7 are a fine aggregate supply chute and a coarse aggregate supply chute disposed on each side of the cement supply chute 5. be. All of the chutes 5, 6, and 7 pass through the top surface of the cover portion 4, and each tip faces above the stirring devices 2, 2 in the container.

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 in such a way as to increase its surface area.

Reference numeral 12 denotes a main pipe for supplying liquid nitrogen, which branches into two on the downstream side of the valve 13, with each tip connected to each nitrogen injection nozzle 14 arranged near the respective water injection nozzle 11. It communicates with 14. Nitrogen injection nozzle 1
The injection directions 4 and 14 intersect with the injection direction of the water injection nozzle 11, and the water whose atomization has been promoted by liquid nitrogen is spread as uniformly as possible within the kneading chamber 3.

Although not shown, if necessary, the kneading container 1
A gas vent is provided to allow nitrogen gas expanded inside to escape to the outside air.

The method of use and operation of the above device will be explained.

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

Next, the water is atomized and the liquid nitrogen is vaporized in the kneading container 1. For this purpose, the water stop valve 9a is opened and water is injected from the water injection nozzles 11. The valve 13 is opened and cryogenic nitrogen is injected from the nitrogen injection nozzles 14.

In this case, the liquid nitrogen is vigorously mixed with the water in the form of mist or raindrops, which promotes atomization of the water and surrounds it with extremely low temperature nitrogen gas. For this reason, rapid heat exchange takes place between water and nitrogen gas, etc.
The water is cooled down to extremely low temperatures 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. Alternatively, it falls onto the material A, such as concrete, which is being stirred by the stirring devices 2. For this reason, the material A such as concrete is not only cooled by contacting the nitrogen gas in the mixing container 1, but also is strongly kneaded by the stirring device 2. It is also cooled from within by finely divided water and/or thin ice.

On the other hand, the extremely low temperature nitrogen gas, etc. that formed the atmosphere with a significant temperature difference inside the kneading container 1 absorbs the heat of the finely divided water, so the temperature rises more than before. Then, the mixture is atomized to the outside of the kneading 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. Thereby, the material A such as concrete can be cooled to an arbitrary temperature, and the concrete to be manufactured can be cooled to a desired temperature range.

The amount of water contained in the final concrete, etc. is the sum of the amount of water injected from the water injection nozzles 11 and the amount of 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.

FIG. 3 shows a part of another mixer according to the present invention, and the difference from the previous embodiment is that a water injection nozzle 1la is used to directly supply water and liquid nitrogen into the inside of material A such as concrete. -11a and the nitrogen injection nozzles 14a, 14a are arranged close to the bottom of the kneading tank section 3.

According to this, in material A such as concrete, water is refined and liquid nitrogen is vaporized, so the cooling caused by evaporation of liquid nitrogen and the low heat of nitrogen gas produced by vaporization of liquid nitrogen. It is expected that this will enable more effective use of the

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 According to this nozzle 15, the advantage is that liquid nitrogen can be vaporized and water can be made fine at the same time with a single nozzle.
And/or there is an advantage that finely divided water can be efficiently frozen.

Further, FIG. 5 shows a part of still another mixer according to the present invention, and the difference from the previous embodiment is that the water injection nozzle ll
c and the nitrogen injection nozzle 14C are provided in a closed position within the kneading container 1.

If the kneading container 1 is not very large, the desired effect can be sufficiently obtained even with such a device. , a predetermined water injection nozzle 11·l is installed in the kneading container 1.
la, llb, llc... and nitrogen injection nozzle 14.
The following effects can be expected with a simple structure in which only 14a, 14b, 14c, etc. are provided.

That is, since water is atomized and liquid nitrogen is vaporized in the kneading container 1, the low heat of nitrogen gas, etc., which conventionally was dispersed into the outside air at a low temperature, can be effectively utilized. Therefore, material A such as concrete can be efficiently cooled.

Therefore, it becomes possible to cool the concrete, etc. to be manufactured to a desired temperature range with a small amount of liquid nitrogen, and there is an advantage that the manufacture of concrete, etc. becomes economical.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an example of a mixer according to the present invention, FIG. 2 is a side view of the same, FIG. 3 is a partially cutaway front view of another mixer according to the present invention, and FIG. FIG. 5 is a sectional view showing a nozzle with a double pipe structure, and a partially cutaway front view showing still another mixer according to the present invention. (Symbol) 1...Kneading container 11, lla, llb, 11c=・Water injection nozzle 14.14a, 14b, 14cm -・Nitrogen injection nozzle

Claims (1)

[Claims] 1. A low-temperature device characterized by being provided with a nitrogen injection nozzle that injects liquid nitrogen into the inside of the kneading container, and a water injection nozzle that injects atomized water into the inside of the kneading container. Mixer for concrete, etc. 2. A patent claim characterized in that the nitrogen injection nozzle and the water injection nozzle are integrated to form a double pipe structure, the inner tube being the nitrogen injection nozzle and the outer tube being the water injection nozzle. A mixer for low-temperature concrete, etc. as described in Scope 1.