JPH0535650B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention involves inserting a nozzle section from the hopper section of a truck mixer into the drum, and injecting liquefied gas from the nozzle section toward the concrete inside to mix the concrete. This invention relates to a concrete cooling device for a truck mixer.

<Conventional technology> In order to achieve a good finish in 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 required large-scale equipment, had poor workability, did not have a large cooling effect, and had various problems such as difficulty in controlling the quality of concrete.

The applicant has been researching and developing a rational method for cooling concrete as an alternative to conventional methods. 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 embodiment of the method for cooling concrete with liquefied gas is to introduce liquefied gas into the rotating drum of a track mixer through a suitable nozzle device to directly cool the concrete during mixing.

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

A nozzle device is inserted into the input hopper of the track mixer, and liquefied gas (liquid nitrogen) is ejected 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 still has considerable sensible heat and is at an extremely low temperature. This extremely low temperature gas dissipating to the outside from the hopper means that cooling energy is wasted. Additionally, the extremely low temperature gas acts directly on the hopper, causing problems such as peeling of the paint on the inside of the hopper and damage to the rubber seals used to prevent concrete from leaking. Furthermore, the surrounding air is cooled by the extremely low temperature gas, and a large amount of white smoke (fog) made 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 confine refrigerant gas in the rotating drum of a truck mixer, effectively utilize cold energy, protect the hopper from low temperatures, and prevent the generation of white smoke. An object of the present invention is to provide a concrete cooling device for a truck mixer.

<Means for Solving the Problems> The concrete cooling device for a truck mixer according to the present invention has a conduit for guiding liquefied gas and a conduit for guiding air, and is inserted into the drum from the hopper part of the truck mixer. a slender composite pipe unit; a cooling nozzle portion disposed at the tip of the composite pipe unit for injecting liquefied gas supplied from the outside into the drum through a pipe line for guiding the liquefied gas; and the composite pipe unit; an air curtain nozzle section disposed on the rear side of the cooling nozzle section, and when the cooling nozzle section injects the liquefied gas into the drum, the air curtain nozzle section The composite tube unit is located in the drum near the outlet of the drum, and air supplied from the outside is blown out radially around the composite tube unit through a conduit that guides the air.

<Function> Liquefied gas is injected into the drum of the track mixer from the cooling nozzle at the tip of the composite pipe unit to cool the concrete being mixed inside. At the same time, the air blown out from the air curtain nozzle forms an air curtain-like air flow near the boundary between the drum and the hopper, thereby trapping the refrigerant gas in the drum and dissipating it to the outside. do not.

<Embodiment> FIGS. 1 and 2 show the configuration of an embodiment of the present invention.

In FIG. 1, numeral 10 is a truck mixer, numeral 11 is a drum mounted on the chassis of the truck, and numeral 12 is a hopper portion installed in alignment with the opening at the rear end of the drum 11. The drum 11 is inclined with the rear end side raised high, and is driven to rotate around a rotating shaft 13.

20 shows a concrete cooling device according to the present invention, which has a stand 2 which is the supporting base for the whole device.
1, the composite pipe unit 22 attached to the stand 21, and the composite pipe unit 2 via the hose 24.
A cylinder 23 that supplies liquid nitrogen to 2 and a hose 2
6 and an air compressor 25 for pumping air to the composite pipe unit 22 through the pipe 6.

As shown in FIG. 2, the composite pipe unit 22 is
It consists of a double tube with an inner tube 22a and an outer tube 22b having a concentric structure, and an air tube 22c attached parallel to the outer circumference of the outer tube 22b with a slight distance. Inner tube 2
2a is a liquid nitrogen cylinder 23 via a hose 24;
The opening at the tip is a cooling nozzle section 27. The outer pipe 22b is connected to a smoke extinguishing device (not shown) via a hose 31, and the opening at the tip thereof is an exhaust port 30. The exhaust port 30 opens slightly toward the rear of the cooling nozzle section 27. Further, the air pipe 22c is connected to the air compressor 25 via a hose 26, and an air curtain nozzle portion 28 is attached to the tip thereof. This air curtain nozzle portion 28 is attached to the outer tube 22b slightly rearward of the exhaust port 30.

When liquid nitrogen is supplied from the cylinder 23, the liquid nitrogen passes through the hose 24 and the inner tube 22a and is ejected from the cooling nozzle portion 27 at the tip. Further, when air is supplied by the air compressor 25, the air passes through the hose 26 and the air pipe 22c and is ejected from the small hole 28a of the air curtain nozzle section 28. The air curtain nozzle part 28 has a cylindrical shape, and has a large number of small holes 28a formed on its circumferential surface, and the air blown out from there is sent to the composite pipe unit 2.
2 in the center and spreads in the radial direction.

The operation of the concrete cooling system for a truck mixer constructed as described above will be explained below.

The truck mixer 10 is parked at an appropriate position relative to the stand 21 of the concrete cooling device 20. The position of the composite pipe unit 22 attached to the stand 21 can be adjusted freely, and by operating these joint mechanisms, the composite pipe unit 22 is inserted from the hopper portion 12 of the track mixer 10 into the drum 11 to a predetermined depth. . Then, while rotating the drum 11 and mixing the concrete inside,
Liquid nitrogen and air are supplied to the composite pipe unit 22. The liquid nitrogen is ejected from the cooling nozzle section 27 into the drum 11 and vaporized, thereby rapidly cooling the concrete being mixed.

Further, pressurized air is blown out radially from the air curtain nozzle portion 28 as described above. This nozzle part 28 is located at the most constricted part at the back of the hopper part 12, and the air flow radially blown out from here forms an air curtain that blocks the opening of the drum 11, and flows along the inner peripheral surface of the hopper part 12. Go outside. This air curtain confines the cryogenic gas within the drum 11, and prevents the cryogenic gas from freely escaping to the outside as in the prior art described above.

Further, when the pressure of the drum 11 increases, the gas inside the drum 11 is discharged from the exhaust port 30 through the outer pipe 22b and the hose 31. This exhaust gas contains a large amount of white smoke components, but if this white smoke is treated with a smoke extinguisher, it can be completely eliminated.

<Effects of the Invention> As explained in detail above, the concrete cooling device for a truck mixer according to the present invention cools the concrete inside by jetting liquefied gas from the hopper part into the drum, and also includes an air curtain in the hopper part. The extremely low temperature gas vaporized in the drum is trapped inside the drum
The cold energy of liquefied gas can be utilized without waste,
The cooling effect of concrete becomes extremely large. In addition, since the extremely low temperature gas in the drum hardly reaches the hopper, damage such as peeling of the paint on the hopper or damage to the rubber seal can be minimized. Furthermore, since very low temperature gas hardly dissipates to the outside from the hopper, the conventional problem of generating a large amount of white smoke is eliminated.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of a concrete cooling device for a truck mixer according to an embodiment of the present invention;
The figure is a partial cross-sectional view showing the main structure of the device. 10...Track mixer, 11...Drum,
12...Hopper part, 20...Concrete cooling device, 21...Stand, 22...Composite pipe unit, 22a...Inner pipe, 22b...Outer pipe, 22c...
...Air pipe, 23...Liquid nitrogen cylinder, 24...
Hose, 25... Air compressor, 26... Hose, 27... Cooling nozzle section, 28... Air curtain nozzle section, 30... Exhaust port, 31... Hose.

Claims (1)

[Claims] 1. A long and thin composite pipe unit that has a pipe line for guiding liquefied gas and a pipe line for guiding air, and is inserted into the drum from the hopper part of the track mixer, and a unit disposed at the tip of this composite pipe unit that carries the liquefied gas. a cooling nozzle section for injecting liquefied gas supplied from the outside into the drum through a conduit guiding the air, and an air curtain nozzle section disposed on the rear side of the cooling nozzle section in the composite pipe unit. , when the cooling nozzle unit injects the liquefied gas into the drum, the air curtain nozzle unit is located within the drum near the outlet of the drum, and is supplied from the outside through a conduit that guides the air. A concrete cooling device for a truck mixer, characterized in that air is blown out radially around the composite pipe unit.