JPH0584786B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to a method for treating white smoke in a cooling concrete construction method for achieving a good finish in hot concrete or mass concrete construction.

<Conventional Technology> In order to achieve a good finish during the construction of hot summer concrete or mass concrete, it is necessary to keep the mixing temperature of the concrete used low. Conventionally, therefore, methods such as cooling materials such as cement and aggregate using cold water or adding ice to concrete mixing water have been adopted. However, these conventional methods have had various problems, such as requiring large-scale equipment, poor workability, not having a very large cooling effect, and difficult to control the quality of concrete.

The applicant has been researching and developing a rational concrete cooling method to replace the conventional method. Recently, a method has been developed that utilizes the latent heat and sensible heat of liquefied gases such as liquid nitrogen to cool the constituent materials of concrete, concrete during mixing, or concrete immediately after mixing. We are also conducting a detailed study of new technology. Regarding these research results, we have already applied for numerous patents and utility model registrations, such as Japanese Patent Application Laid-Open No. 61-286457.

One of the embodiments of the concrete cooling method using liquefied gas is a method in which liquefied gas is introduced into the rotating drum of a track mixer through an appropriate nozzle device to directly cool the concrete being mixed. (Sho 61-229506, etc.) In this method, the cryogenic gas that is vaporized from the liquefied gas is diffused from the mixer drum into the atmosphere, so it is called an open cooling method. On the other hand, there is also a cooling method called a closed type. For example, there is a method in which a concrete transport pipe is passed through the inside of a heat insulating housing, liquefied gas is introduced into the housing, and the concrete passing through the transport pipe is cooled from the surroundings (Japanese Patent Application Laid-Open No. 1983-1982-1).
72581 etc.). Although a closed type is more efficient in utilizing the cold energy of the liquefied gas, an open type is unavoidable depending on the embodiment.

<<Problems to be Solved by the Invention>> As a result of repeating specific experiments using the above method, the following problems occurred, particularly with respect to the open type.

For example, by inserting the nozzle device into the input hopper of a truck mixer, the liquefied gas (liquid nitrogen)
into the rotating drum. The liquefied gas vaporized within the drum gradually dissipates to the outside through the opening of the hopper. This vaporized refrigerant gas also has considerable sensible heat and is extremely low temperature. When this extremely low temperature gas diffuses into the atmosphere from the hopper, the surrounding air is rapidly cooled, and white smoke (fog) made up of minute water droplets or ice crystals blows out from the hopper.
This white smoke becomes such that it obstructs the visibility of the surrounding area, causing an obstruction to traffic and work in the surrounding area.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to make it possible to eliminate white smoke generated by liquefied gas vaporizing and diffusing into the atmosphere to the extent that it does not become a problem. An object of the present invention is to provide a method for treating white smoke in a cooled concrete construction method.

<Means for Solving the Problems> Accordingly, in the present invention, when cooling concrete by supplying liquefied gas to some or all of the concrete constituent materials, water droplets and ice generated by vaporization of the liquefied gas are removed. The white smoke containing crystals was sucked out and passed through an electrostatic precipitator.

<<Operation>> When the white smoke is passed through the electrostatic precipitator, the water droplets and ice crystals that form the basis of the white smoke are collected by the electrostatic precipitator, and the air returns to normal, transparent air.

<<Example>> An example of an embodiment of the cooled concrete construction method according to the present invention is shown in the figure. In the figure, 10 is a track mixer, and 11 is a track mixer 10.
drum mounted on the chassis, 12 is drum 1
Hopper part provided in accordance with the rear opening of 1,
13 indicates the rotation axis of the drum 11.

Reference numeral 20 denotes a cooling nozzle device for cooling the concrete being mixed in the drum 11 with liquid nitrogen.It is mounted at an appropriate height on a pedestal 21, and is connected to the drum from the hopper section 12 of the truck mixer 10 while it is stopped. 11 includes an elongated cooling nozzle device 2
Insert the tip of 0. There is a nozzle 23 at the tip of the cooling nozzle device 20 that injects liquid nitrogen,
This nozzle 23 is connected to a liquid nitrogen cylinder 22 through a hose 24.

As shown in the figure, the cooling nozzle device 20 is inserted into the drum 11, the drum 11 is rotated to mix concrete, and liquid nitrogen from the cylinder 22 is injected from the nozzle 23 and supplied to the concrete being mixed. The liquid nitrogen vaporizes within the drum 11, and the concrete is rapidly cooled by its latent heat and sensible heat. The vaporized nitrogen gas diffuses into the atmosphere from the hopper section 12. At this time, as described above, the surrounding air is cooled by the extremely low temperature nitrogen gas, and white smoke containing water droplets and ice crystals comes out of the hopper section 12.

Reference numeral 30 is an electrostatic precipitator for sucking and eliminating white smoke coming out of the hopper section 12, and a cylinder body 32, which is the main body of the device, is set up near the track mixer 10 on a stand 31. ing. A cylindrical electrode 35 is formed on the inner peripheral surface of the cylindrical body 32, and a linear electrode 34 is arranged on the center line of the cylindrical body 32. A high-voltage power source 33 is provided on the upper part of the cylinder 32, and a positive electrode 35 and a linear electrode 3 are connected to the cylindrical electrode 35.
4 is applied with a negative high voltage DC power source.

There is an air inlet 38 on the outer periphery of the upper end of the cylinder 36, and an opening at the lower end of the cylinder 32 serves as an air outlet 39. Air is sucked into the inlet 38 and the cylindrical body 32
A flexible duct 37 is connected to the inlet side of the fan 36.

Drum 1 from cooling nozzle device 20 as described above.
When cooling the concrete by showering it with liquid nitrogen, the electrostatic precipitator 30 is operated, high-voltage power is applied to the electrodes 34 and 35, and the fan 36 is rotated. And duct 3
The suction end of 7 is brought as close as possible to the opening of the hopper part 12, and as much white smoke as possible coming out of the hopper part 12 is sucked into the duct 37. The white smoke sucked from the duct 37 is sent to the upper part of the cylinder 32, passes through the cylinder 32 from top to bottom, and diffuses to the outside from the outlet 39 at the lower end. While passing through this cylindrical body 32, water droplets and ice crystals, which form the basis of white smoke, are adsorbed by the cylindrical electrode 35 according to the well-known principle of electrostatic precipitation, and from the outlet 39, no white smoke components are released. Clear air comes out. Water droplets and ice crystals adhering to the cylindrical electrode 35 form a large aggregate and fall to the outlet 39 due to their own weight.

Note that when passing the white smoke mentioned above through the electrostatic precipitator, if a large block of ice grows on the dust collecting electrode side, heat the dust collecting electrode side to melt the ice and quickly discharge it. All you need to do is provide a heater.

The method for treating white smoke in the cooled concrete construction method of the present invention is not only carried out in the form described above, but also includes various concrete cooling methods using liquefied gas proposed by the applicants.
This method can be implemented as an open type cooling method in which vaporized cryogenic gas is diffused into the atmosphere. Various embodiments are conceivable; for example, the cooling nozzle device 20 described above cools the concrete in the drum 11 of the track mixer 10 in a suitable building, and the entrance and exit of the building is closed with an air curtain. The building may be partitioned with a wall, and the air inside the building may be sucked into an electrostatic precipitator.

<Effects of the Invention> As explained in detail above, the present invention supplies liquefied gas to some or all of the concrete constituent materials, obtains low-temperature concrete using the latent heat and sensible heat of the liquefied gas, and , the white smoke containing water droplets and ice crystals that is generated when liquefied gas vaporizes and diffuses into the atmosphere is sucked in and passed through an electrostatic precipitator, so extremely low-temperature gas does not enter the atmosphere. This eliminates the inconvenience of the white smoke generated by dispersion obstructing traffic in the surrounding area or impeding work in the surrounding area, and facilitates concrete cooling work and concrete pouring work. You can proceed.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an example of an embodiment of the white smoke treatment method according to the present invention. 10... Track mixer, 11... Drum, 12
...Hopper part, 13... Rotating shaft, 20... Cooling nozzle device, 21... Frame, 22... Liquid nitrogen cylinder, 2
3... Nozzle, 24... Hose, 30... Electrostatic precipitator, 31... Stand, 32... Cylindrical body, 33... High voltage power supply, 44... Linear electrode, 35... Cylindrical electrode, 36... Fan, 37... Duct, 38 ...Entrance, 39...Exit.

Claims (1)

[Claims] 1. Before or after concrete pouring,
When liquefied gas is supplied to some or all of the concrete constituent materials and the concrete is cooled by the latent heat and sensible heat of the liquefied gas, white water containing water droplets and ice crystals is generated due to the vaporization of the liquefied gas. A method for treating white smoke in a cooling concrete construction method, characterized by sucking smoke and passing it through an electrostatic precipitator.