JP2694723B2 - High-strength concrete pipe manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for producing high-strength concrete pipes, and more specifically, a molding method by centrifugal rotation and external vibration and pressure control is appropriately controlled. Such as centrifugal reinforced concrete pipes (so-called fume pipes), which are formed by combining the molding process by centrifugal rotation and external vibration and the molding process and centrifugal molding process by centrifugal rotation and rolling pressure, which are combined under the conditions. It relates to an improved method of manufacturing high strength concrete pipes.

[0002]

2. Description of the Related Art Centrifugal force Reinforced concrete pipes are made by fixing a cage made of rebar to the inner peripheral portion of a tubular molding mold, and while rotating the mold horizontally, concrete is poured in to create a strong centrifugal force. In addition, a dense pipe is molded and then cured, and is generally manufactured as a pipe, a pole, a pile, or the like. However, in the general method for producing a centrifugal concrete pipe as described above, by using concrete having a high water content, a large amount of water flows out during molding, and this water is released to the outside as it is and the environment is reduced. Contamination is caused, and since a part of the poured concrete is separated from the molding mold by centrifugal force and discharged as useless sludge, environmental pollution due to this is also a serious problem. Further, it was not possible to manufacture a satisfactory product having the required physical properties only by centrifugal force.

Various attempts have been made to solve these problems. That is, Japanese Patent Publication Sho 55-51
According to No. 722, concrete having a water: cement ratio of 22 to 33% is put into a molding mold, and at the same time as centrifugal rotation, a rolling roller is used to temporarily roughly fill the entire inner peripheral surface of the molding mold, and then the remaining Discloses a method of centrifuging and compacting concrete pipes by a two-stage molding method in which concrete is charged at regular intervals and is precisely filled with a compaction roller. This method is a method of precise filling using a compaction roller with a strain gauge built-in.Since the tube wall of the compaction roller must be thin in order to increase the sensitivity of the strain gage, Due to this, the mechanical strength of the compaction roller itself is small, it is not possible to generate the molding pressure due to the required compaction pressure, and there is a high risk of damage, and the compaction roller has two parts for the body part and the socket part. Since it is divided into parts, uniform molding is difficult. In addition, there is no specific description about the required centrifugal force and rolling force, and the number of rotations thereof, which are important items, and especially regarding the physical properties of the product manufactured by this method, Since there is no concrete description, it is impossible to estimate the degree of effect of this method.

Further, Japanese Patent Publication Sho 57-42011
No. 30 is an improved version of the above-mentioned centrifugal and compaction molding method, in which 30 g or more (250-2
(70 r.pm) centrifugal force is applied, and at the same time, the pressure roller is rotated at a speed of 10% or more than the inner peripheral surface speed of the pipe,
This is a method of manufacturing a centrifugal roller compaction pipe in which concrete compaction in a certain portion is completed and then the concrete throwing machine is moved to a filling position. In this method, the compaction state of concrete by the compaction roller is detected by the ammeter to detect the motor load and controlled by the controller.Therefore, the pressure of the compaction roller can be directly ascertained. In addition, since two rolling rollers for forming the body portion and the socket portion are used as in the above method, uniform forming cannot be expected. Further, since there is no description about the physical properties of the product by this method, its effect is unknown.

On the other hand, Japanese Patent Publication Sho 58-49371
U.S. Pat. No. 5,837,049 discloses a centrifugal, vibrational and compaction molding process which is an improvement over the two manufacturing processes described above. That is, concrete with a water: cement ratio of 28% or less is 95% of the total input amount.
% Over the entire length of the rotating mold, and after roughly filling with centrifugal force, the impact of the shock generation mechanism is applied to the mold from below in the rotating state, and the remaining concrete (5%) In the same manner as the above-mentioned method, precise filling is performed by using a compaction roller. In this method, the shock generation mechanism is a shock system using a cam, and the amplitude and strength of shock, that is, the degree of shock cannot be changed in various ways, and high shock, that is, high vibration cannot be applied. So
Unable to expect uniform compaction of concrete. Also, the types of products cannot be diversified. Therefore, this method has the drawback that high centrifugal force and high shock, that is, high vibration cannot be properly combined. Further, the precise filling method also has the same drawbacks as the above-mentioned method.

Incidentally, Japanese Patent Publication No. 60-46005.
No. 1 relates to a technique related to centrifugal and vibration impact molding, and relates to a technique for manufacturing a concrete pipe by simply applying a vibration impact after centrifugally rotating a molding mold filled with concrete. The vibration generating mechanism disclosed here uses an oscillating wheel (wheel) having a plurality of protrusions formed at regular intervals on the outer peripheral surface and an eccentric disc, and is not suitable for applying high-speed high vibration. Yes, or because it is not formed by a compaction roller, not only the compaction of concrete becomes insufficient, but also the inner surface of the manufactured pipe is not smooth and the thickness of the pipe wall becomes uneven. It has a drawback that the physical properties of the product cannot be imparted.
On the other hand, Japanese Unexamined Patent Publication No. 60-217110 cannot be said to be efficient centrifugal molding because the centrifugal cover is provided with a splash cover for preventing splashing of water and concrete during centrifugal molding of concrete.

[0007]

As described above, the conventional method for manufacturing a concrete pipe is divided into two parts, a body part and a socket part, and each of them is molded by a corresponding rolling roller. A large amount of water and concrete are scattered during molding, the vibration device is incomplete, and the vibration effect is small,
Since the weight of the molding mold and concrete acts on the compaction roller, the compaction force is insufficient, and because the concrete is partially compacted by force, the appearance of the product is poor due to the unstable molding, and the pipe wall The thickness is also non-uniform and large bubbles are generated. In particular, when the rolling roller and the feeding conveyor are simultaneously operated in the molding mold due to the characteristics of the manufacturing method or the manufacturing apparatus, a small-diameter pipe, for example, an inner diameter of 5
It is difficult or almost impossible to produce tubes below 00 mm. In addition, when centrifugal rotation and vibration are performed in parallel, the effect is small in high-speed centrifugal rotation by this simple mechanical vibration mechanism. In summary, the above-mentioned conventional techniques are merely a combination of centrifugal rotation, vibration, and rolling pressure, and cannot exert an effect more than expected.

[0008] The present invention has a drawback in that the conventional technique has a drawback in the concrete pouring method, and in the molding method, it is not possible to properly combine centrifugal rotation, vibration, and compaction pressure. It was found that it was not possible to manufacture a product having a required strength, a uniform product thickness and a beautiful appearance, and as a result of repeated efforts to eliminate the drawbacks of this conventional technique, The present invention has been completed by eliminating the drawbacks described above.

[0009]

[Means for Solving the Problems] That is, according to the present invention, under controlled conditions, a constant amount of concrete is injected at the same time as water is injected while external vibration is simultaneously applied to the body and socket of the molding mold simultaneously with centrifugal rotation. Molding process that properly combines the molding process by centrifugal rotation and external vibration, and the molding process by centrifugal rotation and rolling by stepwise compaction molding simultaneously with centrifugal rotation and the molding process by high-speed centrifugal rotation as a finishing process By operating the process and the unit equipment for the above unit process under properly controlled conditions, water and concrete do not scatter during centrifugal rotation, concrete sludge does not occur, and environmental pollution is not induced. In addition, within a shortest time, we will manufacture small to large diameter concrete pipes with excellent physical properties and appearance and uniform wall thickness with high productivity by an automated system. To an improved method of producing a high strength concrete pipe which can and.

Therefore, a first object of the present invention is to provide a high-strength concrete which has a beautiful appearance, a uniform product thickness, high strength development and high productivity within the shortest time, and which does not generate concrete sludge. It is to provide an improved method of manufacturing a tube. A second object of the present invention is to provide an improved method for producing a high-strength concrete pipe using a dry concrete injection method by an automatic quantitative injection mechanism. A third object of the present invention is not to separately form a body portion and a socket portion of a concrete pipe, and to perform centrifugal rotation at a high frequency vibration (external vibration) and centrifugal rotation at the same time as centrifugal rotation without scattering of water and concrete. At the same time, it is an object of the present invention to provide a method for producing a high-strength concrete pipe, which comprises secondary molding by stepwise rolling and finish molding by high-speed centrifugal rotation.

[0011]

EXAMPLES In order to achieve the advantages and objects of the present invention as described above, the method of introducing dry concrete, centrifugal rotation, high frequency vibration (external vibration) and stepwise rolling compaction adopted in the present invention are applied. It will be described with reference to the drawings. I. Injection of dry concrete First, a method for injecting dry concrete according to the present invention is shown in FIG.
And FIG. That is, the ratio of water to cement (hereinafter referred to as "water: cement ratio") is 25 to 30.
% Dry concrete C to the upper and lower load cells (lo
Inverter type water injection device 10 by load cell type metering belt conveyor MC for a fixed amount from automatic feeder F equipped with ad cell type two-stage weighing hoppers 8 and 8 '.
Of the vibration generator 5 mounted on the inverter type high frequency vibration generator 4 while starting the discharge on the operating fixed quantity feeding conveyor 7 configured at the tip.
By applying vibration from the outside while advancing into the molding mold 11 during centrifugal rotation, a fixed amount of dry concrete is introduced into the body B of the molding mold 11 at intervals of 100 mm.

In this case, water is jetted from the inverter type water jetting device 10 to the dry concrete to be poured. The tip of the fixed quantity feeding conveyor 7 is the molding mold 1.
When the point just before the point P near the socket S of No. 1 (the position of the fixed quantity feeding conveyor 7 shown by the solid line in FIG. 1-1) is reached,
The primary loading process for the body part B is completed, and at this time, the operations of the fixed amount loading conveyor 7 and the automatic loading machine F are temporarily stopped. Next, the position detection system (PS in FIG. 1) moves the tip of the fixed quantity feeding conveyor 7 to immediately before the opening O of the socket S (the position of the fixed quantity feeding conveyor 7 shown by the broken line in FIG. 4) (at this time, the concrete After the injection and the water injection are not performed), the speed of the measuring conveyor belt MC is automatically decelerated to the speed corresponding to the size of the socket part in order to smoothly insert the socket part in a fixed amount, and the concrete amount is quantified. By discharging the concrete onto the socket portion S in a controlled amount by discharging it onto the charging conveyor 7, the charging is completed within a controlled time together with the water injection. In this manner, the primary injection of dry concrete (50-60% of the total amount) into the body B and the socket S is completed.

On the other hand, at the time of loading into the socket portion S, the belt 7'of the fixed quantity feeding conveyor 7 is rotated to the body portion B which is being vibrated externally at the same time as centrifugal rotation, and the speed is 30 to 80 m / mi.
In n, 50 to 80% of the socket portion input amount is input. Next, the belt 7'speed of the constant quantity feeding conveyor 7 is set to about 60-
While decelerating 70%, part of the remaining dry concrete (1
(0 to 15%), and then the remaining concrete (10 to 35%) is charged to the socket portion inclination start point P while the constant amount charging conveyor 7 is moved backward at a speed of 0.1 to 1 m / min. By doing so, it is possible to prevent the concrete from scattering from the socket portion to the outside during centrifugal rotation. When the primary injection process of concrete up to the socket S is completed, the water injection is interrupted, and at the same time as the backward movement of the constant-quantity injection conveyor 7 is started, the concrete (total amount of 40
(50%) to the body portion B of the molding mold 11 in the same manner as the above-described primary charging step to complete the secondary charging step of dry concrete, and complete the entire charging step of dry concrete to the molding mold 11. .

In the above case, the speed of the measuring conveyor belt MC is 10 to 80 m / min, and the advancing speed of the constant amount feeding conveyor 7 into the molding mold 11 is 2 to 5 m.
/ Min. In addition, the total amount of concrete input to the body portion B when the constant amount input conveyor 7 is advanced is 55 to 7,1.
The total amount of concrete injected into the socket S is 10 to 1,750 kg, and the amount of water injected into the body B during concrete injection is 0.2 to 20 kg.
It is 50 liters, and the water injection amount when the concrete is poured into the socket portion S is 0.1 to 20 liters. The belt 7'speed of the constant quantity feeding conveyor 7 is 30 to 80 m in the body B.
/ Min, 10 to 30 m / in the socket S
It is min.

On the other hand, after the completion of the primary injection process of concrete, the total amount of concrete input to the body B is 55 to 7,125 kg when the fixed amount conveyor 7 for the secondary injection process is moved backward. The backward speed of the constant quantity feeding conveyor 7 is 2 to 5 m / min, and the belt 7'speed of the constant quantity feeding conveyor 7 is 30 to 80 m / min. The amount of water jetted to the body portion B and the socket portion S during forward movement of the constant quantity feeding conveyor 7 is 0.3 to 70 l in total, and the water: cement ratio after the concrete feeding is completed is 26 to 32%. become.

In addition, when the fixed quantity feeding conveyor 7 is moving forward and backward, while the fixed quantity feeding conveyor 7 is moving at intervals of 100 mm, concrete is put in a fixed amount [a load cell provided in the two-stage weighing hoppers 8 and 8 '. Sensing through 9, eg 2 per 100 mm for 300 mm tubes
~ 3kg, 100mm in case of 1,000mm inner diameter tube
33-34 kg per hit]. When the input amount is insufficient, this is detected by the load cell 9 provided in the two-stage weighing hoppers 8 and 8 ′ which are functionally connected to the constant amount input conveyor 7 to operate, and the fixed amount is determined until the input amount. The loading conveyor 7 is stopped, and after the required loading amount is loaded, the fixed amount loading conveyor 7 moves to the next loading position. Similarly, in the case of charging the socket portion S as well, when the charging is completed by the set amount, the constant amount charging conveyor 7 moves (reverses) for the secondary charging process of concrete.

In the case where the concrete is charged, the body portion B is moved when the fixed amount charging conveyor 7 is moved forward (primary charging step).
Is 1.5 to 2.0 minutes, the socket section S is 0.5 to 1 minute, and it is 1.5 to 2 minutes when the vehicle is in reverse (secondary charging step for the body). Therefore, the total charging time is 3.5 to 5 minutes.

Next, the method for forming a concrete pipe by centrifugal rotation, external vibration, and compaction according to the present invention will be described with reference to FIG.
This will be described with reference to FIG. B. Molding of concrete pipe by combination of centrifugal rotation, external vibration and rolling compaction 1. Molding by centrifugal rotation and external vibration A description will be given with reference to FIGS. 1 and 3. Molding mold 11 in which a cage made of rebar is fixedly installed in the inner peripheral portion
To a first centrifugal rotating device equipped with separate rotary drive wheels 2 and 2'having no rotary shaft, by a first transfer carriage 1 composed of a raising / lowering device of a molding mold 11 and a forward / backward moving mechanism. Then, it is placed on the drive wheels 2 and 2'of the above device. Next, while the concrete is being charged according to the above-described concrete charging method (“a. Dry concrete charging”), the molding mold 11 is centrifugally rotated and molded by external vibration. That is, at the same time when dry concrete is discharged from the two-stage weighing hoppers 8 and 8'of the automatic throwing machine F onto the operating fixed-rate feeding conveyor 7, the first centrifugal rotating device rotates the forming mold 11 at low speed centrifugal rotation, that is, 3
The primary centrifugal rotation is performed at 0 to 200 rpm (centrifugal force: 3 to 5 g).

At this time, the inverter type high frequency vibration generator 4 provided on the upper part of the first centrifugal rotating device is lowered to bring the vibration transmission roller 6 of the vibration generator 5 into close contact with the tires 3 and 3'of the molding mold. At the same time, the high-frequency vibration force of 16 to 300 KN (frequency: 3, 6) is applied until the molding process of dry concrete by centrifugal rotation and external vibration is completed.
(00 to 12,000 Hz, amplitude: 0.2 to 0.7 mm)
Is added continuously. When the fixed amount of concrete is added, the molding mold 11 is subjected to medium-speed centrifugal rotation for 1 to 2 minutes by the first centrifugal rotation device while continuously applying vibration under the same external vibration conditions as described above, that is, 50 to 400 rpm. (Centrifugal force:
At 5 to 20 g), the secondary centrifugal rotation is carried out to uniformly distribute and consolidate the injected dry concrete, thereby completing the molding step by centrifugal rotation and external vibration of the present invention.

2. Molding by centrifugal rotation and compaction will be described with reference to FIGS. 2 and 3. After completing the molding process by centrifugal rotation and external vibration, the molding mold 11
The second transfer carriage E having the same structure and function as the first transfer carriage 1 allows the separation type rotary drive wheel W having no rotation axis,
W'is transferred to the side of the second centrifugal rotator equipped with the second
After being placed on the separation type rotary drive wheels W and W ′ of the centrifugal rotating device, centrifugal rotation (50 to 275 r.
pm; centrifugal force: 5 to 10 g), the compaction roller D of the compaction device R is moved into the body portion B of the molding mold 11, and the tip of the compaction roller D is inserted into the bracket I.

At the same time, the compaction roller D and the bracket I are synchronously lowered to a position of 5 to 10 mm from the inner surface of the concrete molding tube T in the molding mold 11, and the molding mold 11 and the compaction roller D are rotated at the same time. Press forming is started. Centrifugal rotation of the molding mold 11 (50 to 275 r.p.
m.) in the compaction molding performed at the same time, the linear pressure of the compaction roller D is set to the first stage: 10 to 20 kg / cm, the second stage: 21 to 30 kg / cm, the third stage: 31 to 40 kg.
/ Cm and the fourth stage: 41-50 kg / cm, and at the same time, the linear velocity of the compaction roller D is set in the first stage: 65-9.
60 m / min, second stage: 70 to 1,050 m / mi
n, the third stage: 75 to 1,080 m / min and the fourth stage: 80 to 1,130 m / min. In this case, the time at each stage is 2 to 60 seconds,
Total 8 to 240 seconds.

When the molding by the centrifugal rotation and the compaction is completed, the compaction roller 1 is moved up and the compact 1 is formed.
It is retracted from the body part B of 1. Next, the molding mold 1
1 is rotated at a high speed of 1 to 10 minutes at 100 to 600 rpm (centrifugal force: 20 to 50 g) by the second centrifugal rotating device to perform a finishing step, thereby completing the molding of the concrete pipe of the present invention. . It is also possible to carry out the above-mentioned molding method under the same conditions while changing the procedure. That is, the method of adding concrete is the same as the above-mentioned "a. Addition of dry concrete", and after "molding by centrifugal rotation and compaction" in the above-mentioned b-2, molding by centrifugal rotation and external vibration in b-1. You may implement the process of ". However, in this case, it is also possible to omit the high-speed centrifugal rotation in the final finishing stage of molding by centrifugal rotation and rolling, and carry out in the final step of (b) -1.

C. Steam curing and demolding The molded concrete tube T in the molding mold 11 that has undergone the above molding process is placed in a steam curing chamber and allowed to stand at ambient temperature for 3 hours.
Leave for 0 minutes to 1 hour. Then, the temperature of the curing room is steam-heated at a heating rate of 15 to 20 ° C. for 60 to 80 hours.
After raising the temperature to ℃, steam aging for 3 to 5 hours under this temperature, then gradually lowering the temperature at a cooling rate of 15 to 25 ℃ every hour, cooling to room temperature and removing from the curing room By doing so, the product according to the invention is obtained.

In carrying out the present invention, the reasons for limiting the numerical values of each condition are as follows. In each of the above-mentioned steps, the preferable condition at the time of adding the dry concrete is as follows: Discharge amount of the measuring belt conveyor: 55 to 7,125 k with respect to the body part of the molding mold at the time of advancing the constant amount supplying conveyor.
g / min, fixed amount feeding amount of conveyor: 55 to 7,1
25kg, Forward moving speed of fixed amount feeding conveyor: 2-5m
/ Min, Belt speed of fixed amount feeding conveyor: 30-80
m / min, discharge amount of the measuring belt conveyor to the socket of the molding mold: 20 to 3,500 k
g / min, fixed amount input of conveyor: 10 to 1,7
50 kg, forward movement speed of fixed amount feeding conveyor: 0.1
1 m / min, constant conveyor belt speed: 10
At 30 m / min, the metering belt conveyor discharge rate: 55-7, 125 kg / min, the metering rate conveyor charging rate: 55-7, to the body of the molding mold when the metering rate conveyor is moving backward. 125 kg, the backward moving speed of the fixed amount feeding conveyor: 2 to 5 m / min, and the belt speed of the fixed amount feeding conveyor: 30 to 80 m / min.
If it is less than or equal to the lower limit of each of the above numerical values, productivity decreases, and if it is above the upper limit, mechanical operation or maintenance becomes difficult.

In addition, in the fixed amount feeding per 100 mm of the fixed amount feeding conveyor, the discharge amount of 2 to 272 kg is a desirable range. If the discharge amount is 2 kg or less, the wall thickness of the concrete pipe becomes thin during molding of the concrete pipe, or an internal defect occurs. If the discharge amount is 272 kg or more, the wall thickness of the concrete pipe is too thick, which hinders the molding process. To finish. In addition, the amount of water jetted from the water jet nozzle of the inverter type water jet device located at the tip of the constant quantity feeding conveyor is 0.
3 ~ 0.8l (in case of 250mm inner diameter pipe) or 57 ~
70 l (in case of 3,000 mm inner diameter pipe) is desirable. If the lower limit value is 0.3 l or 57 l or less, it is difficult to mold the socket part, and the outer surface of the concrete pipe is in a poor state with bubbles, and the upper limit value is 0.8 l or 70 l or more. If so, the phenomenon of inclusion of bubbles occurs in the socket and the body, and unevenness is formed on the inner surface of the concrete pipe.

When the primary centrifugal rotation in the molding stage due to centrifugal rotation and external vibration of the molding mold is 30 rpm or less (centrifugal force: 3 g), the moldability of the concrete against the inner wall of the molding mold is deteriorated, and the concrete is less than the inner surface of the mold. If the cement mortar forms an agglomerate when it is peeled off and the pressure is 200 rpm (centrifugal force: 5 g) or more, the phenomenon of separation from the aggregate occurs. Therefore, the centrifugal rotation speed is 30 to 200 r.p.
The range of m. (centrifugal force: 3 to 5 g) is desirable. On the other hand, when the secondary centrifugal rotation in the molding step due to centrifugal rotation and external vibration is 50 to 40 rpm (centrifugal force: 5 to 20 g), the compaction effect is 50 rpm or less (centrifugal force: 5 g). Is insufficient and the required strength is not reached,
If it is 400 rpm or more (centrifugal force: 20 g), the required rolling effect will not occur.

In the vibration (external vibration) applied to the molding mold by the inverter type high frequency vibration generator, preferable vibration conditions are a frequency of 3,600 to 12,000 Hz,
The vibration time is 3 to 10 minutes with an amplitude of 0.2 to 0.7 mm and a vibration force of 16 to 300 KN. When the frequency is 3,600 Hz or less, the amplitude is 0.2 mm or less, the vibration force is 16 KN or less, and the vibration time is 3 minutes or less, the cement mortar forms agglomerates, and the compaction effect of concrete decreases, and the frequency 1
2,000Hz or more, amplitude 0.7mm or more, vibration force 30
When it is 0 KN or more and the vibration time is 10 minutes or more, the phenomenon of separation between cement mortar and aggregate occurs.

On the other hand, the centrifugal force of the centrifugal rotating device when applying a rolling pressure is 5 to 10 g (50 to 275 rpm), and the linear velocity of the inner surface of the molding mold is 65 to 1,130 m.
/ Min is preferable. Further, the linear velocity and the linear pressure of the compaction roller with respect to the centrifugal rotation range as described above are 65 to 960 m / min and 10 to 20 kg / cm at the first stage compaction, and 70 at the second stage compaction respectively. ~ 1,050 m / min and 21-30 kg / c
m, 75 to 1,080 m / min at the time of the third stage compaction
And 31 to 40 kg / cm, and 80 to 1,130 m / min and 41 to 50 kg / cm during the fourth stage rolling compaction.
It is preferably in the range of cm. In the high-speed centrifugation after compaction, the centrifugal force of the centrifugal rotation device is 20 to 50 g.
The range of (100 to 600 rpm) is preferable.

In the above-mentioned molding by centrifugal rotation and compaction, if the lower limit value of each of the above conditions is not exceeded, the concrete may drop from the wall surface, the adhesive force may be reduced and the compaction force of the concrete may be weakened. If it is more than the upper limit value, the centrifugal force accelerated will cause the molding mold to be splashed out of the centrifugal rotating device, or the phenomenon of separation between cement mortar and aggregate will occur. Incidentally, by the manufacturing method of the present invention, dry concrete is quantitatively charged, and is molded by combining centrifugal rotation, vibration, and compaction, so that the dry concrete is uniformly dispersed in the molding mold, and the compaction effect is sufficient. And concrete does not scatter, and the molding process is divided into stages to transfer the trolley and the automatic control system is used, so the molding efficiency is high, the molding time is shortened, and the appearance of the finished product, that is, the inner surface and the outer surface are Not only does it have such an advantage that it is extremely smooth, but the high-strength concrete pipe of the present invention produced in this manner has the characteristic of exhibiting high strength at a shorter material age than conventional products.

The present invention will be specifically described below with reference to examples. Example 1 (Manufacture of high-strength concrete pipe having an inner diameter of 400 mm) (a) Forming by concrete injection and centrifugal rotation and external vibration A forming mold 11 provided with a reinforcing steel frame (cage) near the inner wall of the periphery was used by the first transfer carriage 1. 1) Transferred to a centrifugal rotating device and placed on the drive wheels 2, 2'of the centrifugal rotating device. Then, by driving the centrifugal rotating device, the molding mold 11 is centrifugally rotated at 111 rpm (centrifugal force:
3g) and at the same time, the vibration generator 4 is lowered, and the vibration transmission roller 6 of the vibration generator 5 is brought into close contact with the tires 3 and 3'of the molding mold so that an external vibration force of 48 KN (frequency 7,200 Hz, amplitude 0.31 mm). ) Mold 1
Immediately after adding to No. 1, concrete injection and water injection to the body portion B of the molding mold 11 were started.

That is, immediately after the centrifugal rotation of the molding mold 11 and the external vibration start, the upper and lower two-stage weighing hoppers 8,
Lower weighing hopper 8'of automatic feeder F equipped with 8 '
A dry concrete having a water to cement ratio (water: cement) of 25% was discharged onto the measuring belt conveyor MC from the body portion B of the molding mold 11 at a discharge rate of 137 kg / min. Then, the dry-type concrete discharged onto the measuring belt conveyor MC is moved (advanced) into the body portion B of the molding mold 11 at a speed of 3 m / min. It was put on the conveyor 7 '. The fixed quantity feeding conveyor 7 in which the concrete loaded from the measuring belt conveyor MC is loaded enters the body portion B of the molding mold 11 and the concrete is fed in a fixed amount per 100 mm with respect to the body portion B in the amount shown in Table 1. Immediately after the start, water was sprayed onto the concrete at the spraying amount shown in Table 1 below from the nozzle of the inverter type water spraying device 10 installed at the tip of the constant quantity feeding conveyor 7.

When the primary injection process of the dry concrete to the body B of the molding mold 11 is completed and the tip of the fixed quantity feeding conveyor 7 reaches the socket S of the molding mold, it temporarily stops (at this time, the automatic feeding machine). F, concrete injection and water injection were also stopped, centrifugal rotation and vibration continued), and concrete was injected under the injection conditions of the socket S shown in Table 2. That is, the discharge amount of the measuring belt conveyor MC to the socket S is set to 60 kg / min,
At the same time as the water injection, concrete is injected into the socket S at a speed of 20 m / min of the constant quantity feeding belt conveyor 7 '.
After injecting kg (60% of the total amount of the socket portion), 4.0 kg of concrete was added while decelerating the speed of the constant amount belt conveyor 7'to 18 m / min.

Thereafter, the constant amount feeding conveyor 7 was moved backward at a speed of 0.5 m / min to the inclination start point P of the socket portion, while the remaining 8 kg of concrete was loaded. When concrete was poured into such a socket portion S, water was sprayed onto the socket portion S under the conditions shown in Table 1. This completes the primary loading process (55% of the total amount) of dry concrete to the body B and the socket S (time required for primary loading: body 1 minute, socket 0.8 minutes, external vibration 5
Minute, centrifugal rotation 5 minutes).

In Table 1 below, per 100 mm of the molding mold body B of the constant quantity feeding conveyor 7 in the primary concrete feeding step (advance of the constant quantity feeding conveyor 7) at the time of manufacturing the centrifugal force reinforced concrete pipe having the inner diameter of 400 mm,
The amount of concrete input and the amount of water injection are shown respectively.

[0035]

[Table 1]

Upon completion of the primary concrete injection process up to the socket S, the operations of the automatic injection machine F, the constant quantity injection conveyor 7 and the water injection were temporarily suspended while continuing the centrifugal rotation and external vibration under the above conditions. After that, the backward movement of the constant quantity feeding conveyor 7 was started. That is, in this case, the injection of water is omitted, the concrete discharge amount of the measuring conveyor belt MC is 137 kg / min, the moving (reverse) speed of the constant amount feeding conveyor 7 is 3 m / min, and the constant amount feeding belt conveyor 7 '.
Table 1 under controlled conditions of moving speed of 60 m / min
The secondary injection process of dry concrete was completed by adding a fixed amount per 100 mm of the molding mold according to the concrete input amount (secondary input: reverse) (secondary input required time: 1 minute) (water for cement) Final ratio: about 27%). As described above, when the addition of concrete is completed, external vibration force of 48 KN (frequency 7,200 Hz, amplitude 0.31 mm) is continuously applied to the molding mold 11 and centrifugal rotation is performed at 203 rpm for 2 minutes (centrifugal force: 10 g).

(B) Molding by Centrifugal Rotation and Rolling Pressure The molding mold 11 which has completed the above step (a) is transferred to the centrifugal rotation and roller compaction molding device by using the second transfer carriage E, and is subjected to centrifugal rotation and rolling compaction. A molding process by pressure was carried out. That is, after placing the molding mold 11 that has been molded by centrifugal rotation and external vibration on the drive wheels W, W'of the second centrifugal rotation device, centrifugal rotation (143 r.pm; centrifugal force: 5) is performed.
g) while moving the compaction roller D of the compaction device forward into the rotating molding mold 11 at a speed of 6 m / min,
At the same time that the tip of the pressure roller is connected to the bracket I, the pressure roller D and the bracket I are synchronously lowered to a position of 5 mm from the inner surface of the molded concrete pipe T, and then the compaction mold 11 is centrifugally rotated and pressure is transferred. Simultaneously with the rotation of the roller D, stepwise rolling compaction was started under the conditions shown in Table 3. That is, the linear pressure of the compaction roller D is set to the first stage: 15 kg
/ Cm (linear velocity: 153 m / min) for 15 seconds, 2nd stage: 25 kg / cm (linear velocity: 162 m / min), 1
5 seconds, 3rd stage: 35 kg / cm (linear velocity: 171 m /
min) for 15 seconds, and the fourth stage: 45 kg / cm (linear velocity: 180 m / min) for 5 seconds under the conditions of 4 stages of roller compaction. When the centrifugal rotation and the compaction by the compaction are completed as described above, the compaction roller D is moved backward from the compact mold 11, and then the compact mold 11 is rotated at a high speed by the second centrifugal rotating device at 406 rpm for 2 minutes. (Centrifugal force: 40 g) to complete the molding of the concrete pipe of the present invention having an inner diameter of 400 mm. In the above process, no concrete slatch was discharged.

(C) Curing and demolding The concrete pipe T in the molding mold 11 which has undergone the above-mentioned molding process is placed in a steam curing chamber and left at ambient temperature for 60 minutes, and then the curing chamber is heated to 20 ° C./hr. Steam heated at a rate to 70 ° C. and maintained at this temperature for 4 hours. Then, 20
The high-strength concrete pipe of the present invention having an inner diameter of 400 mm was manufactured by gradually cooling at a cooling rate of ° C / hr, cooling to ambient temperature, and then demolding. The production conditions of Example 1 are summarized in Table 2, Table 2-1, Table 2-2 and Table 3. Examples 2 to 10 Example 1 except that the conditions shown in Tables 2 to 3 below are used
High strength concrete pipes of various inner diameters according to the present invention according to Examples 2 to 10 were manufactured in the same manner as in.

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

[Table 4]

[0042]

[Table 5]

[0043]

[Table 6]

[0044]

[Table 7]

Comparative Examples 1 to 4 Centrifugal reinforced concrete pipes of the conventional example were manufactured by a conventional method and used as a control and compared with a product by the method of the present invention. That is, using a reinforcing reinforcing frame and a molding mold of the sizes corresponding to the respective Examples 2, 3, 5 and 7,
While adding conventional wet concrete having a ratio of water to cement of 45% by using a screw conveyor, it was molded by centrifugal rotation in a centrifugal rotation device under the respective conditions shown in Table 4 below. After steam curing by the method, the mold was removed from the mold to manufacture the control centrifugal force reinforced concrete pipes of Comparative Examples 1 to 4. A large amount of water is leached on the inner surface of the concrete pipe that has been molded by centrifugal rotation, and the separation phenomenon between cement and aggregate is remarkable, and about 5% of the total input amount of concrete slatch is discharged during centrifugal molding. It was

[0046]

[Table 8]

Test Example The respective concrete pipes manufactured in Examples 1 to 10 and Comparative Examples 1 to 4 were subjected to an external pressure strength test in accordance with Korean Industrial Standards [KS F 4403 (centrifugal reinforced concrete pipe)]. And compared. The results are shown in Table 5, Table 6 and Table 7, respectively.

[0048]

[Table 9]

[0049]

[Table 10]

[0050]

[Table 11]

[0051]

[Table 12]

As is clear from Tables 5 and 6, the concrete pipes according to the present invention show an external pressure strength that is close to the KS standard value at the age of 3 days, and the KS standard value is reached from the age of 7 days. In contrast to the much higher external pressure strength, the conventional concrete pipes (comparative examples) show almost no external pressure strength even at 28 days of age, which does not reach the KS standard value. In particular, as can be seen from Table 7, even when the present invention and the comparative example (conventional example) are compared in the same type of product, the present invention shows that the external pressure strength at each age is different from that of the comparative example (conventional example). Shows a remarkable increase rate of.

[0053]

From the above results, therefore, it can be seen that the method of the present invention exhibits higher productivity in a shorter manufacturing process than the conventional method and a large external pressure strength at a short material age.
Since the product according to the present invention can be sufficiently used from the age of 7 days, it can be commercialized with a short age. As described above, the present invention constitutes an automated integrated production process line and can continuously carry out the unit process, and the molding method by centrifugal rotation, vibration and rolling force is appropriately combined and controlled. Since it can be carried out under specified conditions, there is no splash of water and concrete, beautiful appearance, high strength development within the shortest time, prevention of concrete sludge formation,
Since it is possible to mass-produce high-strength concrete pipes having a uniform product thickness and high productivity, its significance in industrial use is great.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of an apparatus for molding dry concrete into a molding mold according to an embodiment of the present invention and molding by centrifugal rotation and vibration.

FIG. 2 is a cross-sectional configuration diagram of an apparatus for molding by centrifugal rotation / rolling pressure according to an embodiment of the present invention.

FIG. 3 is a manufacturing process diagram showing an example of the present invention.

FIG. 4 is a sectional view of an opening of a socket of the molding mold of FIG.

Claims (23)

(57) [Claims] 1. In the production of a concrete pipe by centrifugation, vibration and compaction molding, (a) Weighing of concrete having a ratio of water to cement of 25 to 30% by an automatic throwing machine equipped with a load cell type two-stage weighing hopper. A predetermined amount is discharged from the conveyor belt to the fixed amount feeding conveyor, and while the fixed amount feeding conveyor is moved forward into the molding mold, the discharged concrete is subjected to low-speed centrifugal rotation and external vibration at the same time by the first centrifugal rotation device. In the body part in the molding mold, at the same time, at a constant interval, at the same time, at the same time, water is injected in a controlled amount from the inverter type water injection device, concrete is injected into the body part, and the constant amount conveyor is When reaching just before the opening of the socket of the molding mold, the speed of the measuring conveyor belt is reduced to The total amount of concrete into the socket portion by discharging a predetermined amount of concrete into the socket portion at the same time as the water injection from the inverter type water injection device at the same time as the water injection from the inverter type water injection device. The primary injection step of the concrete which inputs 50-60% of the amount, and the water injection is interrupted after the primary injection step of the concrete, while continuing the low speed centrifugal rotation and the external vibration of the molding mold, Simultaneously with the start of reverse travel, a secondary concrete injection process is performed in which the remaining concrete is quantitatively injected into the above-mentioned body part at regular intervals, and after these processes are completed, the molding mold is subjected to medium speed centrifugation while continuously applying external vibration. Centrifugal rotation and external vibration molding step of rotating, and (b) After completion of the centrifugal rotation and external vibration molding step, the molding mold (2) While centrifugally rotating with the centrifugal rotating device, the compacting roller of the compacting device is introduced into the molding mold, and is lowered to a position of 5 to 10 mm from the inner surface of the concrete pipe molded, and pressure in four stages and Centrifugal rotation and compaction molding step of stepwise compaction molding at the same time as centrifugal rotation at speed, and (c) After completion of the centrifugal rotation and compaction molding step, the molding mold is subjected to high-speed centrifugation with the second centrifugal rotation device. A method for producing a high-strength concrete pipe, comprising a high-speed centrifugal rotation molding step as a finishing step of rotating. 2. The method for producing a high-strength concrete pipe according to claim 1, wherein the speed of the belt is 10 to 80 m / min when discharging the concrete from the measuring belt conveyor to the constant quantity feeding conveyor. 3. The method for producing a high-strength concrete pipe according to claim 1, wherein the rate of advance of the constant quantity feeding conveyor into the molding mold is 2 to 5 m / min. 4. The centrifugal rotation and the low speed centrifugal rotation in the first centrifugal rotation device in the external vibration molding step are 30 to 200 rpm.
The centrifugal force in this case is 3 to 5 g, and the method for producing a high-strength concrete pipe according to claim 1, wherein 5. The vibration in the centrifugal rotation and the external vibration forming process is applied with an oscillating force of 16 to 300 KN using an inverter type high frequency vibration generator, and the frequency in this case is 3.
600-12,000Hz, amplitude 0.2-0.7mm
The method for producing a high-strength concrete pipe according to claim 1, wherein 6. The amount of concrete discharged from the weighing belt conveyor is 55 to 7,125 when the concrete is charged into the body portion when the fixed amount feeding conveyor is advanced into the molding mold.
kg / min, forward speed 2-5 of the above-mentioned fixed amount feeding conveyor
m / min, the belt speed of the above-mentioned fixed amount feeding conveyor is 30 to
80 m / min, the concrete feeding amount of the constant amount feeding conveyor is 55 to 7,125 kg, and the feeding time is 1.5 to 2.
It is 0 minutes, The manufacturing method of the high strength concrete pipe of Claim 1 characterized by the above-mentioned. 7. The high-strength concrete according to claim 1, wherein the amount of water jetted to the body portion at the time of concrete injection at the same time as the advance of the constant quantity injection conveyor into the molding mold is 0.2 to 50 l. Pipe manufacturing method. 8. Injecting concrete into the socket portion when advancing into the molding mold of the above-mentioned fixed amount feeding conveyor,
Belt amount of the constant quantity feeding conveyor at the time of advancing into the body portion is 30 to 80 m / min, and the amount of the socket portion is 50 to 8
0% is input, and the belt speed of the above-mentioned fixed amount input conveyor is 6
After loading 10 to 15% while decelerating from 0 to 70%, set the above-mentioned fixed quantity feeding conveyor to 0.1 at the socket inclination start point.
The remaining 10 to 35% of concrete is added while moving backward at a speed of ˜1 m / min.
A method for producing the high-strength concrete pipe described. 9. The concrete feeding to the socket portion is performed at a belt speed of the constant amount feeding conveyor of 10 to 30 m.
/ Min, the concrete input amount is 10 to 1,750 kg, and the input time is 0.5 to 1 minute, the method for producing a high strength concrete pipe according to claim 1 or 8. 10. The method for producing a high-strength concrete pipe according to claim 9, wherein the amount of water sprayed when the concrete is poured into the socket portion is 0.1 to 20 liters. 11. When advancing into the molding mold of said fixed quantity feeding conveyor, the total amount of water sprayed to the body and socket is 0.3 to 70 l, and the water: cement ratio of concrete is 25 to 30%. Claim 1 characterized in that
The method for producing a high-strength concrete pipe according to any one of 6, 7, and 8. 12. The secondary speed of the constant quantity feeding conveyor for secondary charging to the body portion after the primary charging of the concrete is 2 to 5 m / min, and the belt speed of the conveyor is 30 to 80 m / min. The method for producing a high-strength concrete pipe according to claim 1, wherein the total amount of concrete to be fed into the body portion when the fixed amount feeding conveyor is moved backward is 55 to 7,125 kg. 13. The concrete loading amount of the fixed amount feeding conveyor at constant intervals is a constant amount while being sensed by a load cell provided in a two-stage weighing hopper while the fixed amount feeding conveyor moves 100 mm in a molding mold. The method for producing a high-strength concrete pipe according to any one of claims 1, 3, 6, 7 and 12, characterized in that it is charged. 14. The method for producing a high-strength concrete pipe according to claim 13, wherein the amount of concrete input per 100 mm of the fixed amount input conveyor is 2 to 272 kg. 15. The high-strength according to claim 1 or 8, characterized in that a concrete amount is injected into the socket portion of the constant-quantity feeding conveyor while being sensed by a load cell provided in a two-stage weighing hopper. Concrete pipe manufacturing method. 16. After completion of the second step of adding concrete to the molding mold, the vibration force of 16 to 300 KN (frequency 3, 60) is applied to the molding mold by the first centrifugal rotating device.
50 ~ 400r.pm (centrifugal force: 5 ~ 5 while applying external vibration of 0 ~ 12,000Hz, amplitude 0.2 ~ 0.7mm)
The method for producing a high-strength concrete tube according to claim 1, wherein the method is centrifugally rotated at 20 g). 17. The method for producing a high-strength concrete pipe according to claim 1, wherein the centrifugal rotation condition in the second centrifugal rotation device is 50 to 275 rpm (centrifugal force: 5 to 10 g). 18. The molding by the pressure roller at the same time as the centrifugal rotation in the second centrifugal rotation device, the pressure and speed of the pressure roller are the first step: 10 to 20 kg / cm and 65, respectively.
~ 960 m / min, 2nd stage: 21-30 kg / cm
And 70 to 1050 m / min, 3rd stage: 31 to 40
kg / cm and 75 to 1080 m / min, 4th stage:
The high-strength concrete according to claim 1 or 17, characterized by centrifugal rotation and compaction molding in which the compaction is performed at 41 to 50 kg / cm and 80 to 1130 m / min, and the rolling time for each stage is 2 seconds to 60 seconds. Pipe manufacturing method. 19. After the centrifugal and compression molding, the molding mold is treated with a second centrifugal rotating device at 100 to 600 rpm (centrifugal force:
The method for producing a high-strength concrete pipe according to claim 18, characterized in that high-speed centrifugal rotation is performed at 20 to 50 g) for 1 to 10 minutes. 20. The automatic dosing machine, a constant dosing conveyor,
The method for producing a high-strength concrete pipe according to claim 1, wherein an integrated production line including a first centrifugal rotating device and a vibration generating device and a second centrifugal rotating device and a compacting device is used. 21. The centrifugal rotating device wherein each of the first centrifugal rotating device and the second centrifugal rotating device has a separate rotary drive wheel without a rotary shaft.
Or the method for producing a high-strength concrete pipe according to 20. 22. A first transfer carriage is used for transferring and placing the molding mold on the first centrifugal rotating device, and a second transfer carriage is used for transferring and placing the molding mold on the second centrifugal rotating device. 21. The method for producing a high-strength concrete pipe according to claim 1, wherein 23. The transfer carriage is configured to raise a molding mold,
23. The method for manufacturing a high-strength concrete pipe according to claim 22, wherein the descending device and the forward-backward moving mechanism are provided.