JPS61199912A - Continuous feeder for concrete - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an apparatus for continuously supplying concrete, and more particularly to an apparatus for continuously supplying mixed ready-mixed concrete at low temperatures.

(Prior Art and Opening Problem) As is well known, concrete generates heat due to the hydration reaction of cement, and as the temperature rises and falls, thermal stress is generated, which causes cracks to occur.

Therefore, in the case of ready-mixed concrete that is poured during the first hour when the ambient temperature is particularly high, or so-called mass concrete that uses artificial concrete, the effect of the heat generation mentioned above is noticeable, so it is specified in the concrete standard manual that the ready-mixed concrete should be poured. Temperature regulations are in place.

On the other hand, as ready-mixed concrete supply, concrete constituent materials such as aggregate, cement, and water slurry are supplied individually from one end and are kneaded while being transferred to the other end to produce ready-mixed concrete continuously. There is one that uses an auger mixer to feed the water.

This type of VR installation can be installed at a construction site adjacent to V4.
Compared to transporting mixed ready-mixed concrete in a mixer truck, this method has advantages such as less deterioration in the consistency of the concrete, but it has the following problems when complying with the above-mentioned temperature regulations.

That is, conventionally, ready-mixed concrete supplied by this type of apparatus has been cooled by means of pre-cooling each of the constituent materials of Concrete 1 to 1, or by means of mixing crushed ice into the mixing water.

However, with the former method, it is troublesome to individually control the cold temperature, and with the latter method, crushed ice melts into water, making it troublesome to manage the water-cement ratio.
Furthermore, it is difficult to cool fresh concrete sufficiently by cooling with crushed ice.

This invention was made in view of these problems, and its purpose is to provide sufficient cooling without requiring complicated management and without affecting the consistency of fresh concrete. The purpose of this invention is to provide a device for continuously feeding ready-mixed concrete.

(Means for Solving the Problems) In order to achieve the above object, the present invention transfers concrete constituent materials supplied individually from one end side to the other end side, and mixes them during transfer to make ready-mixed concrete. In a concrete feeding device equipped with an auger mixer that continuously supplies concrete, a plurality of pouring outlets [1 are provided along the transfer direction of the auger mixer, and a liquefied low-temperature medium is injected into the fresh concrete from the pouring outlets. , characterized by cooling fresh concrete by vaporizing the medium.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 to FIG. 3 show one example of concrete according to the present invention.
1 shows an embodiment of the connection supply device.

The feeding device shown in the same figure, as shown in the overall configuration in FIG. 1, supplies cement, aggregate, and water individually.

An auger mixer 10 that continuously produces and supplies ready-mixed concrete by kneading admixtures and the like while transferring them to the other end, and a storage of constituent materials installed adjacent to the rear end of the auger mixer 10. It is roughly composed of a device 12.

This storage device 12 contains cement A and aggregate B.

Water C is separated and stored, cement A is stored in a first supply bag W12 composed of a screw conveyor, etc., aggregate B is stored in a second supply device 13, water C is stored in a water supply pump 14, and further , the admixture contained in the tank 15 is supplied to one end of the auger mixer 10 by a metering pump 16 for a set amount.

As shown in detail in FIG. 2, the auger mixer 10 includes a case 20 having a substantially U-shaped cross section with an open upper end, a cover 22 that closes the opening of the case 20, and a cover 22 provided along the axial direction inside the case 20. a rotating shaft 24, a plurality of augers 26 and mixing blades 28 alternately fixed to the rotating shaft 24, and a rotating shaft 2 protruding from the distal end side of the case 20;
4 and a motor 26 fixed to the case 20.
The above-mentioned input port 30 for the concrete constituent material is opened on the upper surface of one end of the cover 22, and the discharge port 32 for mixed fresh concrete is opened on the lower surface of the other end. This is the same equipment used to load concrete onto plant ships.

The feeding device shown in the figure has the following features, particularly in the auger mixer 10.

That is, as shown in FIGS. 2 and 3, a plurality of spouts 34 and 34 are provided along the axial direction on the side surface of the case 20 of the auger mixer 10, and each spout 3
A liquefied low-temperature medium E that rapidly vaporizes in the atmosphere, such as liquid nitrogen or liquefied carbon dioxide, is injected from 4 through the vibrator 36 .

Here, each spout 34 can be installed at a slightly forward position of the kneading blade 28, and the pipe 36 can be inserted from the side along the rotational direction of the kneading blade 28 so as to be inclined downward. Preferably, with this configuration, the fresh concrete is vigorously stirred in the vicinity of the mixing blade 28, and the low-temperature medium E comes into contact with more of the fresh concrete, increasing the cooling efficiency and stopping the cooling of the concrete. When this occurs, concrete is prevented from entering the pipe 36.

Note that, in normal cases, freezing of the spout 34 can be prevented by stopping the supply of the low-temperature medium E before the concrete cross-contamination is stopped.

A gas exhaust port 36 is open opposite the exhaust port 32.

In this case, case 20. Cover 22. The pipe 38 and the like that introduce the low temperature medium E into the spout 34 are themselves made of a heat insulating material, or are covered with a heat insulating sheet or the like.

In the continuous supply device configured as described above, the cement A, aggregate B, and water C1 admixture supplied to the auger mixer 10 are kneaded by the auger 26 and the mixing blade 28 while being transferred to the discharge port 32, and The liquefied low-temperature medium E is poured out from the spout 34 during cross-talk and transfer, and the mixed ready-mixed concrete is cooled by removing heat from the latent heat of vaporization and sensible heat when the low-temperature medium E evaporates.

Then, the gas whose temperature has increased due to vaporization is discharged to the outside from the exhaust port 36.

Now, when the fresh concrete is cooled as described above,
The liquid or low-temperature medium E has a lower melting point than water or water with crushed ice, and when it exchanges heat with the fresh concrete, it rapidly becomes a gas and is released to the outside without remaining inside. As well as allowing the concrete to cool down sufficiently,
There is no change in the consistency of ready-mixed concrete or changes in the properties of ready-mixed concrete.

In the above-mentioned device, when 60 m3 of fresh concrete is continuously supplied per hour, liquid nitrogen is used as the low temperature medium E, and if 150 β of this is supplied per minute, the kneading temperature is approximately 10°C lower than that of concrete without cooling. It was confirmed that it is possible to continuously supply ready-mixed concrete with a low

Figure 4 shows ready-mixed concrete made with the device of the present invention,
Temperature change when constructing a concrete structure using ready-mixed concrete made with conventional equipment (Figure A) 9
This is the measurement result of the generated stress (B in the same figure).

In the figure, the solid line indicates the device of the present invention, the same dotted line indicates the conventional device, and the dotted line in FIG. 4 indicates the surrounding outside air temperature.

As is clear from FIG. 4, when fresh concrete prepared by the apparatus of the present invention is used, the temperature rise relative to the outside air temperature is significantly reduced, and the amount of temperature drop is also reduced.

Therefore, as shown in Figure B, the tensile stress is reduced, making it safer against cracks.

In addition, when cooling the fresh concrete, a temperature sensor is inserted into the cooled fresh concrete, and the injection of the liquefied low-temperature medium E is controlled by the sensor, and an electric heater is wound around each spout 34, for example. It is desirable to install an antifreeze device.

Furthermore, the low-temperature medium E that has been gasified by heat exchange with the fresh concrete is not immediately discharged to the outside from the exhaust port 38, but is collected and guided to the aggregate B and water C storage device 22 immediately before use. By contacting with the aggregate B and water C, the constituent materials of the concrete may be cooled in advance to assist in lowering the temperature of the ready-mixed concrete after mixing.

(Effects of the Invention) As described above in detail in the embodiments, according to the continuous concrete supply device according to the present invention, by simply injecting the liquefied low-temperature medium without requiring complicated management, Effects such as being able to effectively cool fresh concrete -1- can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an overall view of the feeding device of the present invention, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a longitudinal sectional view of FIG. 2. FIG. 4 is a graph showing changes over time in temperature and stress of placed concrete of the present invention and a conventional example. 10... Auger mixer 12... First supply device 13... Second supply device 14... Water supply pump 16... Metering Pump 20... Case 22...
・Cover 24...Rotating shaft 26...
... Auger 28 ... Kneading blade 30 ...
...Input port 32...Discharge port 34.
...Spout 36...Vibe 38
...Exhaust port A...Cement
B: Aggregate C: Water D: Admixture E:
...Liquefied low-temperature medium patent applicant: Obayashi Co., Ltd. Attorney: Kensuke Shiro Figure 1 Figure 4

Claims (1)

[Claims] In a concrete supply device equipped with an auger mixer that transfers concrete constituent materials supplied individually from one end side to the other end side, mixes these materials during transfer, and continuously supplies ready-mixed concrete, the auger mixer 1. A continuous concrete supply device, characterized in that a plurality of spouts are provided along the transfer direction, a liquefied low-temperature medium is injected into the fresh concrete from the spouts, and the fresh concrete is cooled by vaporization of the medium.