JPH0444883B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a centrifugal manufacturing apparatus for concrete pipes such as concrete piles, concrete poles, and humid pipes.

[Background Art] The centrifugal manufacturing method that is generally used to manufacture concrete pipes is as shown in Figs. , After installing core materials such as reinforcing bars, cement,
Fresh concrete made by mixing water, sand, fine stones, etc. is filled or poured, and this is placed on a centrifugal table 2 on which a driving roller 22 and a driven roller 23 are installed at a distance, and the above-mentioned Rotate the formwork 1 around its axis, and the fresh concrete inside the formwork 1
This is done by being pressed against the inner peripheral surface by centrifugal force and maintaining the contact state for a while.

By the way, the quality of a concrete pipe as a product depends not only on its uniformity and amount of cement used, but also on the magnitude of compaction force, which is equivalent to centrifugal force in centrifugal manufacturing. The greater the amount of cement and the greater the compaction force, the higher the strength can be obtained. However, the centrifugal manufacturing method has the following problems.
In other words, in order to increase the degree of compaction, formwork 1
It would be better to increase the rotational speed of the rollers 22 and 23, but this requires a high-output drive motor 20, as well as the accuracy of the formwork 1 and the rollers 22 and 23. , micro-vibrations with a short vibration period occur in the formwork 1 in a direction perpendicular to the axial direction, which increases the problem of cost and noise, and at the same time causes a decrease in strength due to material separation, and the micro-vibrations impede the solidification of fresh concrete. Therefore, molding takes a long time. When increasing the amount of cement, the amount of water used must be reduced, but unlike low-slump concrete with poor fluidity, which cannot be formed without applying strong compaction force, the above-mentioned Since it is difficult to increase the compaction force, it is not possible to improve the strength by using low-slump ready-mixed concrete. Therefore, concrete pipes formed by traditional centrifugal manufacturing methods are
I couldn't hope for something with high strength.

[Objective of the Invention] The present invention has been made in view of the above points, and its purpose is to provide a centrifugal manufacturing apparatus for concrete pipes that can easily produce concrete pipes with high strength. .

[Disclosure of the Invention] The present invention provides a concrete pipe centrifugal manufacturing apparatus that is equipped with a rotation drive means for rotating a cylindrical formwork filled with or injected with ready-mixed concrete around its axis. The vibration generating means generates vibration using compressed air or electric power as a power source. It is characterized in that it is removably attached to the center of the end face, and is connected to a power source via a rotary joint or slip ring, and the pressurizing means is removably connected to the other end face of the formwork. The fresh concrete that is in contact with the inner circumferential surface of the formwork is pressed against the inner circumferential surface of the formwork by the centrifugal force caused by the rotation of the formwork, and is further pressed against the inner circumferential surface of the formwork by the pressure of pressurized air, and is also shaken by vibration. The aim is to improve density and remove internal air bubbles and moisture.

Even if the rotation speed of the formwork is not very high, the internal pressure is high and the compaction force is increased.
Vibration is what increases the density and is what makes it possible to use low slump fresh concrete. The value of the internal pressure is set appropriately depending on the purpose of the concrete pipe, the type of fresh concrete used, the water-cement ratio, the maximum rotation speed of the formwork, etc. The value should be several times to several tens of times the force. In addition, the vibration here should of course not disturb the solidification of the fresh concrete, and it is preferable that the main vibration direction be in the axial direction of the formwork, but it is not limited to this, and the internal pressure It can be set as appropriate in the same way as the value of .

The present invention will be described below in detail based on the illustrated device.A cylindrical formwork 1 that is divided into halves in the upper and lower halves is closed at both ends, and the outer circumference is spaced apart in the axial direction. A plurality of body rings 10 are provided. On the other hand, the centrifugal table 2 that rotates the formwork 1 around its axis includes a plurality of drive rollers 22 attached at intervals in the axial direction to a drive shaft 21 that is rotationally driven by a motor 20, and each drive roller. 2
2 and a plurality of paired driven rollers 23, and the formwork 1 is placed on the centrifugal stand 2 so that the cylinder ring 10 is placed on the pair of driving rollers 22 and driven rollers 23. By the rotation of the drive roller 22 by the motor 20, the formwork 1 rotates around its axis. In the figure, 24 is a bearing.

Here, as is clear from FIG. 2, the end plate 11 attached to one end surface of the formwork 1 is provided with a coupling 12 equipped with a check valve in the center thereof, and an air conditioner is connected to the end plate 11. The presser 15 connects to the coupling 12 via the rotary joint 14.
The pipes are connected at some points. 1 in the diagram
6 is a solenoid valve, 17 is a pressure gauge, 18 is a support for the rotary joint 14, and 19 is an air hose. End plate 1 attached to the other end surface of formwork 1
As shown in FIG. 3, an air vibrator 30 that generates vibrations by reciprocating a built-in piston using air pressure supplied from the air compressor 15 is installed in the center of the air compressor 15, using means such as bolts, couplings, or chucks. are removably connected. Also, between the air compressor 15 and the air vibrator 30, a solenoid valve 36 and a pressure gauge 3 are connected.
7, a flow meter 38, a rotary joint 34, etc. are installed.

After assembling the formwork 1 and installing the pile caps 50 and core materials 5 such as reinforcing bars inside, the formwork 1 is filled or poured with ready-mixed concrete made by mixing cement, water, sand, fine stones, etc. death,
This is placed on the centrifuge table 2. And at this time,
The formwork 1 and the air vibrator 15 are connected at the coupling 12, and the air vibrator 30 is also connected. Thereafter, the formwork 1 is rotated around its axis so that the ready-mixed concrete in the formwork 1 is brought into contact with the inner peripheral surface of the formwork 1 by centrifugal force, and the solenoid valve 16 is opened to allow the air compressor 15 to Pressurized air is sent into the formwork 1 to increase the air pressure within the formwork 1, and the air vibrator 30 is activated to vibrate the formwork 1 in its axial direction. The rotation speed of the formwork 1 is gradually increased from low speed to medium speed and then to high speed. The air pressure inside the formwork 1 is also gradually increased until it reaches a value several to several tens of times the centrifugal force. Vibration is applied to the formwork 1 a little while after the start of rotation.

FIG. 7 shows the control system. The control device 8 includes a motor 20 for rotating the formwork 1 by the centrifugal table 2.
In addition to controlling the air compressor 15 and the solenoid valve 16 by feeding back the pressure data from the pressure gauge 17, the pressure data from the pressure gauge 37 is also controlled.
Based on the data from the flowmeter 38 and the flowmeter 38, the solenoid valve 36
Adjust the opening. This allows the frequency and amplitude to be adjusted.

Now, the ready-mixed concrete filled inside the formwork 1 spreads over the entire inner periphery of the formwork 1 due to the centrifugal force caused by the rotation of the formwork 1, and is also spread around the inner periphery due to the centrifugal force and a stronger internal pressure. pressed against the surface. Even if the rotation speed of formwork 1 is not so high,
A powerful compaction force can be obtained, and even low-slump fresh concrete can be reliably formed. In addition, the axial vibration applied from the air vibrator 30 is
Shaking the fresh concrete increases the degree of compaction and pushes out air bubbles and moisture, improving the degree of compaction.

FIG. 6 shows an example in which a vibration motor 31 having an eccentric weight added to the rotor is used as the vibration generating means in place of the air vibrator 30. In the figure, 32 is an inverter, and 33 is a slip ring. The vibration motor 31 is set so that the direction of its rotation axis is perpendicular to the axial direction of the formwork 1. Note that it is of course possible to use other types of vibration generating means than the above two types.

[Effects of the Invention] As described above, in the present invention, air is introduced into the mold to increase the internal pressure of the mold, while the mold is rotated around its axis and vibration is applied. In addition to centrifugal force, strong air pressure acts on the ready-mixed concrete inside the frame, making it possible to obtain a large compaction force.At the same time, the vibrations shake the ready-mixed concrete, increasing its compaction density and pushing out air bubbles and moisture. The pressure means applies force to the concrete pipe in the radial direction, and the vibration generation means applies force in a direction perpendicular to the direction of the force applied by the pressure means. In order to apply vibration in the axial direction, the vibration applied by the vibration generating means does not inhibit the increase in compaction force by the pressurizing means. Compared to manufacturing equipment, it is possible to manufacture concrete pipes with higher strength, and it is also possible to form concrete with low slump, so in this respect as well, it is possible to obtain concrete pipes with high strength. It is also possible to significantly shorten the time required for molding. Since the vibration generating means is attached to the end face of the formwork, the vibrations generated by the vibration generating means are directly transmitted to the formwork, and not only can the vibrations be efficiently generated, but also the vibration generating means is located at the center of the end face of the formwork, so the vibration generated by the vibration generating means is transmitted equally to each part of the cylindrical formwork, and the vibration generating means is attached to the end face of the formwork. However, since it is connected to the power source via a rotary joint or slip ring, there is no problem in operating the vibration generating means, and moreover, the vibration generating means and the pressurizing means are detachable. Because of this structure, there is no need to provide vibration generating means or pressurizing means for each formwork, which is economical.

[Brief explanation of the drawing]

Figure 1 is a schematic front view of the device according to the present invention, Figure 2 is a schematic front view of the device according to the invention;
Figures a and b are a partial front view and a cutaway plan view of the same as the above, Figure 3 is a partial front view of the same as the above, Figure 4 is a cross-sectional view of the same as the above, Figure 5 is a block circuit diagram of the same as the above, and Figure 6 is another one. 7 is a front view of the conventional example, and FIG. 8 is a side view of the same example, 1 is a formwork,
2 is a centrifugal force, 15 is an air compressor, 30 is an air vibrator, and 31 is a vibration motor.

Claims (1)

[Scope of Claims] 1. In a concrete pipe centrifugal manufacturing apparatus equipped with a rotation drive means for rotating a cylindrical formwork filled with or poured with ready-mixed concrete around its axis, air is introduced into the formwork to form the mold. Equipped with a pressurizing means that increases the internal pressure of the frame and a vibration generating means that applies axial vibration to the formwork, the vibration generating means that generates vibration using compressed air or electric power as a power source can be freely attached to and detached from the center of the end face of the formwork. A centrifugal manufacturing device for concrete pipes, which is attached to the mold, is connected to a power source via a rotary joint or a slip ring, and has a pressurizing means detachably connected to the other end surface of the formwork. 2. The centrifugal concrete pipe manufacturing apparatus according to claim 1, wherein the vibration generating means is a vibration motor having an eccentric weight added to a rotor.