JPH0549005B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> This invention relates to a concrete plant, and particularly relates to a concrete plant in which fresh concrete made by mixing cement, aggregate, etc. is cooled with liquefied gas. .

≪Conventional techniques and their problems≫ It has long been known that the quality of construction is largely dependent on the temperature at which the concrete used is mixed, in the case of concrete poured in hot weather or mass concrete placement for dam construction. It is being

For this reason, methods are generally used to cool the constituent materials of concrete, such as cement and aggregate, using cold water, or by adding ice to the water used for mixing concrete. was.

However, such conventional methods require large-scale equipment such as cooling equipment and ice makers, are not easy to work with, do not have a large cooling effect, and are difficult to control the quality of concrete. I had a problem.

The applicant has been researching and developing conventional concrete cooling methods that have had such problems, and has recently developed a method for cooling concrete using the latent heat and sensible heat of liquefied gases such as liquid nitrogen. It has been found that it is extremely effective to cool the constituent materials, concrete during mixing, or concrete immediately after mixing.

As a result of this research, for example,
Japanese Patent No. 229506 provides a device for directly cooling concrete during mixing by introducing liquefied gas into the rotating drum of a concrete mixer truck using a nozzle device.

However, with the device disclosed in this publication,
For example, when a large amount of concrete is placed in a short period of time, such as in dam construction, there is not enough concrete to be supplied.

To deal with this problem, a concrete plant should be built near the construction site, as was used in conventional dam construction, but in this case, a large amount of concrete would be heated using liquefied gas. There was no suitable equipment for continuous cooling.

The present invention was made in view of the above circumstances, and its purpose is to provide a concrete plant that can continuously cool a large amount of concrete with liquefied gas.

<<Means for Solving the Problems>> In order to achieve the above object, the present invention provides a silo containing cement, a storage tank containing aggregate, and a method for separately transporting cement from the silo and storage tank. A measuring device that measures cement and aggregate,
In a concrete plant equipped with a kneading mixer that adds various additives and a predetermined amount of water as necessary to a predetermined amount of cement and aggregate measured by this measuring device, the mixer mixes the mixture. A cooling mixer is provided to knead the mixed concrete again, and a first pump supplies liquefied gas for cooling the concrete from a storage tank to the cooling mixer.
A second supply passage for supplying liquefied gas for cooling cement or aggregate from the storage tank to the silo or storage tank is connected to the second supply passage.

<<Operation>> According to the concrete plant with the above configuration, liquefied gas is supplied to the silo or storage tank to pre-cool the cement or aggregate, and since the liquefied gas is supplied to the cooling mixer, the mixing mixer If the mixed concrete is put into this, it can be continuously cooled by the latent heat and sensible heat of the liquefied gas.

<<Example>> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a concrete plant equipped with a cooling function according to the present invention.

The concrete plant shown in the figure includes two silos 10, 10 containing cement, a storage tank 12 containing aggregate, a measuring device 14 for measuring cement, aggregate, etc. and a kneading mixer 16 for kneading.

The weighing device 14 is installed on the third floor of a tower-shaped structure 17, and above it is a cement hopper 18 that temporarily stores cement and aggregate.
Two aggregate hoppers 20 and two aggregate hoppers 20 are installed, and an on-off valve 22 is provided at the lower end of each of these hoppers 18 and 20, respectively.

At a position corresponding to the fourth floor of the structure 17, a flow straightening device 24 is installed above the aggregate hopper 20 to distribute the aggregates being sent, and a frame body 26 surrounds the flow straightening device 24. A fan 28 is provided inside the enclosure.

The cement in the silo 10 is fed to the cement hopper 18 side by feeding compressed air with a compressor 32 into a supply pipe 30 provided between the silo 10 and the cement hopper 18.

Further, the aggregate in the storage tank 12 is sent to the aggregate hopper 20 side via a belt conveyor 34 installed between the storage tank 12 and the aggregate hopper 20.

The kneading mixer 16 is located on the second floor of the structure 17 and is provided below the measuring device 14, and is equipped with a hopper 36 for discharging the mixed concrete at its lower end.
6 is bifurcated so that the discharge direction can be changed.

The basic configuration of the concrete plant as described above is the same as that of conventional plants of this type, but
The concrete plant shown in FIG. 1 is characterized by having a cooling function as explained below.

That is, on the first floor of the structure 17,
Two closed type cooling mixers 38, 38 are provided below the discharge hopper 36 of the kneading mixer 16.

A first gas supply passage 42 from two tanks 40, 40 containing liquefied nitrogen gas is connected to each of these cooling mixers 38, 38.

The liquefied gas supply passage from the tank 40 has a second gas supply passage 44 branched from the first gas supply passage 42, and this second gas supply passage 44 is connected to the cement hopper 18 and the aggregate hopper. 20 and each of these hoppers 18, 2
The cement and aggregate in the container are pre-cooled.

Further, the cement hopper 18 and the aggregate hopper 20 are connected to the cooling mixer 38 by a third gas supply passage 46, and the cooling mixer 38
The liquefied gas supplied to the hoppers 18 and 20 is introduced into each hopper 18 and 20 after being vaporized.

A concrete pump 52 having a receiving hopper 50 is arranged below the cooling mixer 38.

Now, in the concrete plant configured as described above, cement is sent from the silo 10 to the cement hopper 18 by the compressor 32, and aggregate is individually sent from the storage tank 12 to the aggregate hopper 20 by the belt conveyor 34. send to.

The cement and aggregate fed into each hopper 18, 20 are transferred to the weighing device 1 by opening the on-off valve 22.
4 and supplied in a predetermined amount to the kneading mixer 16, where various additives and a predetermined amount of water are added and kneaded.

The concrete mixed in the mixer 16 is fed into the cooling mixer 38 via the discharge hopper 36, and while driving the mixer 38, the concrete is mixed in the first mixer 16.
Open the valve of the gas supply passage 42 of the tank 4.
Liquefied nitrogen gas is supplied from 0.

The supplied liquefied nitrogen gas removes heat from the concrete in the process of vaporizing and cools it, and the vaporized gas is supplied to the cement hopper 18 and the aggregate hopper 20 via the third supply passage 46. The cement and aggregate contained in the hoppers 18 and 20 are pre-cooled.

In this case, the second gas supply passage 44 may be opened in advance to pre-cool the cement and aggregate to be introduced into the metering device 14.

The above operations are performed in sequence as a series, and the concrete that has been sufficiently cooled by the cooling mixer 38 is then pumped to the pouring site via the concrete pump 52.

<<Effects of the Invention>> As explained in the embodiments above, according to the concrete plant equipped with a cooling function according to the present invention, cement or aggregate is pre-cooled using the latent heat and sensible heat of liquefied gas, and Since the concrete can be cooled after mixing, a large amount of concrete can be continuously and efficiently cooled.

[Brief explanation of drawings]

FIG. 1 is an overall layout diagram showing an embodiment of a concrete plant according to the present invention. 10... Silo, 12... Storage tank, 14... Measuring device, 16... Mixer for kneading, 38... Mixer for cooling, 42... First gas supply passage, 44...
Second gas supply passage, 46...third gas supply passage.

Claims (1)

[Scope of Claims] 1. A silo containing cement, a storage tank containing aggregate, a measuring device for measuring cement and aggregate sent individually from these silos and storage tanks, and this measuring device In a concrete plant equipped with a kneading mixer that adds various additives and a predetermined amount of water as necessary to a predetermined amount of cement and aggregate measured by A cooling mixer for mixing concrete again is provided, a first supply passage for supplying liquefied gas for concrete cooling from a storage tank is connected to the cooling mixer, and cement or bone is supplied from the storage tank to the silo or storage tank. A concrete plant equipped with a cooling function, characterized in that a second supply passage is connected to supply liquefied gas for cooling materials.