JPH05116135A - Concrete kneading apparatus - Google Patents

Abstract

PURPOSE:To efficiently cool concrete in small space without requiring a large- scale cooling plant or a complicated device. CONSTITUTION:A snow horn 9 is provided to a mixer main body 2 having kneading space 5 formed therein in a freely detachable manner and liquefied carbon dioxide 13 is supplied to the mouth part 91 of the snow horn 9 through a cooling medium supply mechanism 11 and compressed air 35 is supplied to an air supply port 92 through an air supply means 30. The liquefied carbon dioxide 13 is subjected to adiabatic expansion in the snow horn 9 to become dry ice 13' which is, in turn, flewn by compressed air 35 to be supplied to a member to be kneaded and concrete during kneading is subjected to endothermic cooling by the heat of sublimation of the dry ice 13'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete kneading apparatus which can reduce temperature cracks generated in mass concrete or hot concrete.

[0002]

2. Description of the Related Art Conventionally, in order to reduce temperature cracks generated in mass concrete or hot concrete, ice (so-called flake ice) is required when kneading concrete.
A method of cooling concrete or aggregate with liquid nitrogen is used.

[0003]

However, the method of using ice requires a large-scale ice-making plant separately from the kneading device. Therefore, if the temperature of ice is lowered to the freezing point, the W / C (water Its cooling capacity is very limited as it has to be mixed into the concrete so as not to increase the cement ratio). Further, in the method using liquid nitrogen, it usually takes a very long time to cool it because it is used in the form of spraying it into the whole mixer car filled with concrete after kneading, and liquid nitrogen has a very low temperature of -196 degrees. However, the cold heat cannot be used effectively enough, that is, the cooling efficiency in this method is 30 to 4
It is very inefficient at 0%. Therefore, there has been proposed a method of modifying the raw concrete plant so that the aggregate such as sand or gravel is cooled in advance in a cooling facility using liquid nitrogen before kneading. However, since such an aggregate cooling facility requires a large-scale and complicated device exclusively for liquid nitrogen, it is a plan to install such an aggregate cooling facility in an existing ready-mixed plant where space and economy are limited. Is hard to be adopted. In view of the above circumstances, the present invention provides a concrete kneading device capable of efficiently cooling concrete in a small space without the need for large-scale plant facilities or complex devices for ice making or aggregate cooling. To do.

[0004]

That is, the present invention has a mixer body (2) in which a kneading space (5) is formed so that concrete (26) can be stored therein, and the mixer body (2) is provided. A kneading mechanism (6) is provided so as to be capable of kneading the members (19), (20), (25) to be kneaded in the kneading space (5), and the upper part (7) of the mixer body (2) is provided. )
The cylindrical snow horn (9) is attached to the snow horn (9).
Attach one end of the above to the kneading space (5) so as to open,
The other end (91) of the snow horn (9) is provided with a refrigerant supply nozzle (12), the refrigerant supply nozzle (12) is provided with a refrigerant supply means (11), and the refrigerant supply nozzle (12) is made of liquefied gas. Refrigerant (13) is freely connectable and compressed air (35) is supplied to one end (92) of the snow horn (9).
And is provided with a compressed air delivery means (30) capable of delivering the compressed air. The numbers in parentheses () indicate the corresponding elements in the drawings for the sake of convenience, and therefore the present description is not limited to the description in the drawings. below

The same applies to the column of [Operation].

[0005]

According to the present invention, the refrigerant supply nozzle (12) supplies the refrigerant (13) to the snow horn (9), and the refrigerant (13) is adiabatically expanded in the snow horn (9). From the above, it acts so as to be dropped onto the kneaded members (19), (20), (25) in the form of being blown off by the compressed air (35).

[0006]

EXAMPLE FIG. 1 is a view showing an example of a concrete kneading apparatus according to the present invention.

As shown in FIG. 1, a kneading plant 1 for kneading concrete has a mixer main body 2 by a forced two-axis mixing mixer, and the mixer main body 2 has a leg portion 21 and a frame of the concrete plant. It is fixedly supported by 3rd grade. Inside the mixer main body 2, there is provided a kneading space 5 formed in the shape of a twin sinus so as to be able to store concrete. At the upper end of the mixer main body 2, there is an input port 22, for example, the mixing space 5 is shown in the drawing. It is provided so as to be openable and closable so as to open upward. In the kneading space 5, a pair of left and right mixing rotors 6 in the figure are provided so as to be respectively arranged in the left and right sinus portions of the kneading space 5 which are formed in a double sinus shape. In FIG. 6, two kneading blades 61 are provided so as to be rotatable about a rotation shaft 62 along the plane of the drawing. A drive source (not shown) for rotationally driving each mixing rotor 6 is fixed to the outside of the mixer main body 2, and a discharge port (Fig. (Not shown) is provided so as to be openable and closable.

By the way, in the upper part of the mixer body 2 in the figure,
A pair of left and right inspection windows 7 in the figure are provided in such a manner that the kneading space 5 is opened. Each inspection window 7 is provided with a snow horn 9 made of a steel pipe or the like with a beveled tip, and a seal ( It is removably mounted in an airtight manner via (not shown). An air supply path 10 is formed in each snow horn 9 so as to descend from the mouth 91 side toward the kneading space 5, and the air supply path 10 is provided for supplying a cooling medium to the kneading space 5. Nozzle 12 is inserted from the upper side of the air supply passage 10 in the drawing. A refrigerant supply mechanism 11 is connected to the nozzle 12 in a form capable of supplying a refrigerant composed of liquefied gas, for example, liquefied carbonic acid 13 in the embodiment, to the nozzle 12. That is, in the refrigerant supply mechanism 11, a tank 15 in which liquefied carbonic acid (LCO ₂ ) 13 is stored so as to be in a liquid state by applying a predetermined pressure P, is appropriately provided in the frame 3 or the like of the concrete plant. The liquefied carbonic acid 13 stored in the tank 15 is held at a predetermined temperature, that is, −20 degrees C. A feed pipe 16 is connected to the tank 15 so as to feed the liquefied carbon dioxide 13 stored in the tank 15, and a valve 17 is provided in the feed pipe 16 to open the valve 17. Thus, the liquefied carbonic acid 13 in the tank 15 is intervened in such a manner that an arbitrary amount can be fed to the nozzle 12 side.
In addition, normally, that is, except when kneading the cooled concrete, a window member formed in a plate shape, for example, is attached to the inspection window 7 in a freely openable / closable manner through a hinge or the like, and the window member is opened. By doing so, the state in the kneading space 5 can be visually confirmed. Further, on the bottom side of the snow horn 9, that is, on the lower side in the drawing, an air supply means 30 for supplying compressed air 35 to the kneading space 5 and an air nozzle 32 arranged at the tip of the air supply means 30 are sent. It is arranged so as to open to the airway 10. That is, the air supply pipe 31 is connected to the supply source side shown on the right side of the air nozzle 32 in the figure, and the air supply pipe 31 is connected to the air supply pipe 31.
It is inserted into an air supply port 92 which is formed in the bottom portion of the snow horn 9 depending on the pipe diameter. A compressor 33 shown in the lower right part of the drawing is connected to a supply source side of the air supply pipe 31 shown on the right side of the drawing through a valve 36. Therefore, the air supply means 30 includes the compressor 33.
The compressed air 35 generated by the valve 36, the air nozzle 3
With the pressure adjusted to any pressure via 2, the mixer main body 2
The air supply passages 10 are arranged on both the left and right sides in the figure, and are jetted toward the middle part of the kneading space 5 in the figure.

Since the kneading plant 1 has the above-mentioned structure, when kneading concrete using the kneading plant 1, first, the weight of sand or gravel is reduced through a hopper or the like of the concrete plant. Insert the aggregate 19 such as
2 into the kneading space 5, and the mixing rotor 6
Emptiness through. In the present embodiment, since the mixer main body 2 is a forced two-axis kneading mixer, the mixer main body 2 is fixed on the frame 3 or the like when the kneading is performed, and in the kneading space 5, only the kneading blade 61 is the rotating shaft 62. Is rotated in the direction parallel to the paper surface in the figure, and the aggregate 19 is kneaded. Then, at this time, the valve 17 of the refrigerant supply mechanism 11
Is opened by a predetermined amount, the liquefied carbonic acid 13 is sent out into the feed pipe 16 in a form in which the pressure is released from the tank 15 by an amount corresponding to the opening amount of the valve 17. Then, the liquefied carbonic acid 13 sent out from the tank 15 in a pressure-released form is pressure-fed in the feed pipe 16, and from the tip portion of the nozzle 12 into the feed passage 10 of the snow horn 9. Is ejected. The liquefied carbon dioxide 13 discharged into the feed passage 10 has been pressure-fed in the feed pipe 16, and the cross-sectional area of the pipe passage is narrowed through the nozzle 12, and the feed passage 10 has a mouth 91. Since it is formed so as to descend downward from the side toward the kneading space 5, the feeding path 10
It is discharged into the kneading space 5 in the form of being jetted downward from the inspection window 7 portion without staying inside. Then, the liquefied carbonic acid 13 which has been kept in a liquid state at about −20 ° C. by applying a predetermined pressure P in the tank 15 is discharged from the snow horn 9 until it is discharged into the kneading space 5. Adiabatic expansion and solidification occur in the feeding path 10, that is, dry ice 13 'is formed, and the dry ice 13' exhibits a temperature state of about -80 degrees C. On the other hand, the dry ice 1
At the same time when the 3'is discharged into the kneading space 5, the compressor 33 is driven to generate compressed air 35, which is pumped at a predetermined pressure Q through a valve 36 to remove the compressed air 35 from both sides in the drawing. The compressed air 35 is jetted toward the kneading section 5, that is, in the arrow R (or R ′) direction in the figure by discharging the compressed air 35 from the air nozzles 32, 32 at a predetermined pressure Q ′. In this way, when the compressed air 35 is jetted in the direction of the arrow R (or R ') in the figure via the air supply means 30, the dry ice 13' produced by the adiabatic expansion of the liquefied carbonic acid 13 in the snow horn 9 is generated. It is quickly delivered to the kneading space 5 without staying in the feeding passage 10. Therefore, the dry ice 13 ′ adheres to the pipe wall inside the snow horn 9 in a frost-like manner, and the frost-like dry ice 13 ′ forms a lump to block the feeding path 10, or the lump-like dry ice 13 ′. 'Is prevented from falling into the kneading space 5. Again, dry ice 13 '
The liquefied carbon dioxide discharged from the nozzle 12 is maintained because the temperature of the inside of the feed passage 10 is maintained so that the temperature does not drop extremely by promptly sending the liquefied carbon dioxide from the feed passage 10 to the kneading space 5. 13 can always be adiabatically expanded in a moment to become dry ice 13 '. Then, the production operation from the liquefied carbonic acid 13 to the dry ice 13 'is promoted one after another, that is, the dry ice 13' is constantly produced, so that the refrigerant supply mechanism 11 is provided with a stable cooling capacity. . Then, the dry ice 13 'released into the kneading space 5 is blown off by the compressed air 35 having a predetermined pressure Q', which is ejected from the left and right sides of the kneading space 5 in the arrow R (or R ') direction in the figure. As a result, the dry ice 13 ′ blown off from the left and right sides is agitated with each other, and the powder particle size is homogenized in the upper part of the kneading space 5 in the figure. by the way,
In the kneading space 5, since the aggregates 19 are kneaded through the mixing rotor 6 in the right and left sinuses formed in the shape of twin cavities, the dry state in a stirring state in which the powder particle diameters are uniform in this way. The ice 13 'does not concentrate and drop at one place of the aggregate 19 in the dry kneading, that is, the ice 13' is evenly dispersed and drops as shown by the arrows S and S'in the figure. Then, aggregate 19 and dry ice 13 '
In addition to the rotating operation of the aggregate 19 and the dry ice 13 ′ via the mixing rotor 6, the dry ice 13 ′ has already been agitated and homogenized via the air supply means 30 as described above, so that the aggregate 19 is removed. By evenly dispersing and dropping in, it is homogeneously mixed within an extremely short time. Thus, when the aggregate 19 and the dry ice 13 ′ are mixed, as described above, the dry ice 13 ′ exhibiting −80 ° C. absorbs heat from the aggregate 19 being kneaded at room temperature to sublime. As a result, the temperature of the aggregate 19 is significantly reduced. That is, since the dry ice 13 ′ has a solid state, it does not float in the kneading space 5 and the aggregate 19 is rotating.
Mix evenly in the inside to cool the aggregate 19 efficiently,
It is possible to provide a sufficiently low temperature state.

On the other hand, since the dry ice 13 'absorbs heat from the aggregate 19 and sublimes to become carbon dioxide gas, the carbon dioxide gas is discharged to the outside of the mixer main body 2 through the charging port 22 or another exhaust port. , Avoids the incorporation of carbon dioxide into freshly produced fresh concrete 26 '. That is, almost all of the dry ice 13 ′ becomes carbon dioxide gas during the kneading of the aggregate 19. Therefore, by discharging the dry ice 13 ′ from the charging port 22 and other exhaust ports within a short time, the carbon dioxide gas becomes fresh. The risk of remaining in the concrete 26 and contributing to its neutralization after hardening of the concrete is avoided. The amount of the dry ice 13 ′ can be set arbitrarily by simply adjusting the opening / closing state of the valve 17, so that the aggregate 19 is cooled to the most economical temperature state. Kneading can be done easily. That is, dry ice 1
As 3'is endothermic sublimation, it becomes carbon dioxide gas and is discharged from the kneading space 5, and does not remain in the fresh concrete 26 after kneading, so that W / C (water cement ratio) of concrete Although any amount can be dropped into the kneading space 5 regardless of the above, the amount of the dry ice 13 'is based on the kneading concrete temperature, the cement temperature, the aggregate particle size, etc. which are specified in advance by the specifications and the like. Then, the aggregate 19 can be arbitrarily adjusted so as to be in a predetermined temperature state (for example, a predetermined temperature state such as −10 degrees C. or 0 degrees C or less).

In this way, when the temperature of the aggregate 19 is lowered to an arbitrary value by the dry ice 13 'via the coolant supply mechanism 11, the aggregate 19 is made of sand or gravel having a large grain size. Since the aggregate 19 has a large heat storage capacity as compared with the powder such as the cement 20 and the admixture 23, the aggregate 19 now holds a large amount of cooling heat. Then, next, the cement 20 and the admixture 23, which have been preliminarily compounded and weighed, and water 25 are dropped into the kneading space 5 through the input port 22 through the concrete plant, and thereby the fresh concrete 26 is main-kneaded. Here, the inlet 22
Since the cement dropped from the plant was stored in cement silos, etc.
The temperature of the water 25 is close to the outside air temperature, and therefore, the temperature of the water 25 is relatively high with respect to the temperature of the kneading concrete defined by the above specifications. Therefore, when the main kneading is performed in this manner, the aggregate 19 that retains a large amount of cooling heat as described above is combined with the cement 20 and the admixture 23 that are powder or fluid under these relatively high temperature conditions. The water 25 is efficiently cooled in a short time. Then, when these materials in the kneading space 5 are subjected to the main kneading until a predetermined property is obtained, the sufficiently cooled good quality fresh concrete 26 is discharged from the discharge port of the mixer body 2. Therefore, the cold heat of the liquefied carbonic acid 13 (dry ice 13 ′) dropped into the kneading space 5 through the refrigerant supply mechanism 11 during the dry kneading of the aggregate 19 is temporarily stored in the aggregate 19 having a large heat storage capacity. As a result, 70-80% (experimental value) of the cold heat of the liquefied carbonic acid 13 is effectively used for cooling the fresh concrete 26 without being wasted by releasing heat to the outside of the mixer body 2 or the like. Therefore, when mass concrete or hot concrete is molded by the fresh concrete 26 thus kneaded and discharged, a solid structure with a significantly reduced possibility of temperature cracking can be formed.

Although the snow horn 9 is detachably attached to the inspection window 7 of the mixer body 2 in the above-described embodiment, the snow horn 9 is provided at the upper portion of the mixer body 2, for example, the charging port. It may be attached to 22 or the like.
By removing the snow horn 9, the kneading plant 1 can be easily used not only for kneading cooled concrete as described above, but also for kneading ordinary concrete or other concrete.
When the snow horn 9 is deteriorated or damaged, the snow horn 9 is not replaced without replacing the mixer main body 2.
Since only the kneading plant 1 can be exchanged and the kneading plant 1 can be used again for kneading the cooled concrete, the maintenance of the apparatus is easy, that is, economical concrete kneading can be performed using a simple apparatus. Further, the air supply means 30 sends the compressed air 35 to the discharge end of the snow horn 9 which is the end of the feed passage 10 to mix the dry ice 13 ′ generated in the feed passage 10 with the kneading space. 5 may be configured in any manner as long as it can be sent to Therefore, the air nozzle 32 is connected to the air supply port 92 of the snow horn 9.
However, it may be attached to any one of the mixer main body 2 and the like, for example, the inlet 22
A portion or a central portion of the kneading space 5 in the drawing may be arranged, or an air nozzle 32 may be provided in the refrigerant supply mechanism 11 of the nozzle 12 portion from which the liquefied carbonic acid 13 is discharged. Even in this case, as a result, the compressed air 35 is discharged to the portion of the inspection window 7 on the discharge end side of the snow horn 9.
Will be sent. Further, in the above-described embodiment, the example in which the dry ice 13 ′ made of the liquefied carbonic acid 13 is used as the refrigerant for cooling the aggregate 19 is described, but the refrigerant is fresh concrete to be kneaded by the kneading plant 1. It suffices if the fresh concrete 26 can be cooled without increasing or decreasing the concrete W / C (water cement ratio) of 26, so that, for example, liquefied carbonic acid 13 can be replaced with other liquefied gas such as liquefied nitrogen. Absent. Further, the time when the refrigerant is dropped into the kneading space 5 may be any time during the step of kneading the fresh concrete 26, for example, the aggregate 1
Before dropping 9 into the kneading space 5, or at the same time as dropping the aggregate 19, or when dropping the cement 20, water 25, or the like,
Furthermore, it does not matter whether the material to be kneaded is dropped during the main kneading or after the main kneading.

[0013]

As described above, according to the present invention, there is provided the mixer main body 2 in which the kneading space 5 is formed so that concrete such as fresh concrete 26 can be stored, and the mixer main body 2 is mixed. The kneading mechanism such as the rotor 6 is provided with the aggregate 19, cement 20, water 2 in the kneading space 5.
5 and other members to be kneaded are provided so that they can be kneaded,
A cylindrical snow horn 9 is attached to the upper part of the inspection window 7 of the mixer body 2 so that one end of the snow horn 9 is opened to the kneading space 5, and the mouth 91 of the snow horn 9 is attached.
A coolant supply nozzle such as a nozzle 12 is provided at the other end of the coolant supply unit, and a coolant supply means such as a coolant supply mechanism 11 is supplied to the coolant supply nozzle, and a coolant including a liquefied gas such as liquefied carbonic acid 13 is freely supplied to the coolant supply nozzle. Since the compressed air 35 is connected and the compressed air delivery means such as the air supply means 30 capable of delivering the compressed air 35 to one end of the air supply port 92 of the snow horn 9 is provided, the refrigerant supply nozzle causes the snow horn 9 to operate as a refrigerant. The refrigerant can be adiabatically expanded in the snow horn 9 and then dropped onto the member to be kneaded in the form of being blown off by the compressed air 35. That is, the refrigerant is powdered by adiabatic expansion in the snow horn 9, but the powdered refrigerant is quickly kneaded without staying in the snow horn 9 via the compressed air delivery means. In addition to being sent to the space 5, the particle diameter of the powder is homogenized and then drops onto the member to be kneaded, so that the member to be kneaded and the refrigerant are uniformly mixed in the kneading space 5 in a short time. . Then, the member to be kneaded is rapidly cooled by the endothermic sublimation action of the refrigerant made of liquefied gas. Therefore, when the concrete kneading device according to the present invention such as the kneading plant 1 is used for kneading the concrete, the refrigerant can be directly charged into the mixer main body 2. It does not need to be provided separately from 2, that is, tank 1
It is possible to easily and efficiently cool the concrete by requiring only a small space for storing the refrigerant such as 5. When mass concrete or hot concrete is placed by using the concrete cooled by the refrigerant supply means in this way, a solid structure with less possibility of temperature cracking can be constructed. Since the refrigerant mixed in the material to be kneaded is composed of liquefied gas, it is gasified during the kneading of concrete and discharged from the concrete, so that the risk of neutralization of concrete is avoided, There is no concern that the refrigerant will affect the concrete W / C (water cement ratio) that must be taken into consideration when cooling with ice or the like. Further, when the compressed air delivery means is provided in the snow horn 9, it is possible to prevent the refrigerant from adhering to the tube wall inside the snow horn 9 and forming a lump. Therefore, the temperature inside the snow horn 9 is maintained so as not to be extremely lowered, so that the liquefied gas supplied to the refrigerant supply nozzle can be steadily adiabatically expanded into a refrigerant. That is, the refrigerant is stably supplied to the kneading space 5. Further, it is also prevented that the lumped refrigerant that has adhered to the pipe wall in the snow horn 9 falls to one place on the member to be kneaded, so that the member to be kneaded and the refrigerant are even more uniform. Therefore, the concrete can always be cooled in a stable state. When the snow horn is detachably attached to the mixer main body, the snow horn 9 can be removed from the mixer main body 2 so that the refrigerant is not supplied to the kneading space 5. That is,
Since the mixer main body 2 can be used for producing ordinary concrete other than cooled concrete, it is possible to manufacture the mixer main body 2 for the present invention by modifying an existing suitable mixer main body. Can be done easily. Therefore, one concrete kneading device can be used for kneading cooled concrete and for kneading other concrete, for example, to concretely operate the concrete plant efficiently and economically produce concrete. ..

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a concrete kneading device according to the present invention.

[Explanation of symbols]

 1 …… Kneading plant (concrete kneading device) 2 …… Mixer body 5 …… Mixing space 6 …… Mixing rotor (kneading mechanism) 7 …… Inspection window (upper part of mixer body) 9 …… Snow horn 91 …… Mouth ( The other end of the snow horn 92 ... Air supply port (one end of the snow horn) 11 ... Refrigerant supply mechanism (refrigerant supply means) 12 ... Nozzle (refrigerant supply nozzle) 13 ... Liquefied carbon dioxide (refrigerant) 19 ... Aggregate (material to be mixed) 20 ... Cement (material to be mixed) 25 ... Water (material to be mixed) 26 ... Fresh concrete (concrete) 30 ... Air supply means (compressed air delivery means) 35 ... Compressed air

Claims (3)

[Claims] 1. A mixer main body having a kneading space formed therein so that concrete can be stored therein, and a kneading mechanism is provided in the mixer main body so that the kneading member in the kneading space can be kneaded. Provided, a cylindrical snow horn is mounted on the upper part of the mixer main body, one end of the snow horn is attached to the kneading space, and a refrigerant supply nozzle is provided at the other end of the snow horn. A concrete kneading device comprising a refrigerant supply means, which is connected to the refrigerant supply nozzle so as to freely supply a refrigerant composed of a liquefied gas, and is provided with a compressed air sending means capable of sending compressed air to one end of the snow horn. 2. The concrete kneading apparatus according to claim 1, wherein the compressed air delivery means is provided on the snow horn. 3. The concrete kneading device according to claim 1, wherein the snow horn is detachably attached to the mixer body.