JPH01105704A - Method for feeding reinforcing fiber - Google Patents

Abstract

PURPOSE:To make it possible to realize uniform and fully dispersed state of fiber in a kneader by a method wherein tufts of artificial organic fibers, which are carried with a belt conveyer, are scraped off with a rotor, which is provided above the tip part of the conveyer and has a large number of projections, in nearly short fibers and, immediately after that, fed in material to be reinforced. CONSTITUTION:A scraping-off roller 4 is provided at the end of a belt conveyer 3. Tufts of fibers, which are carried with the belt 3, are scraped down by projections, which are provided on the surface of the rotor 4, so as to separate the tuft of fibers into nearly short fibers in order to fall down the separated fibers. In order to feed the scraped-down fibers in material to be reinforced with no stagnation, a method to send the scraped-down fibers to a fiber sending fan 6 is employed for pneumatically sending and feeding them to a kneader through pneumatic conveying piping. As a result, the fibers in the state of the tuft of fibers, are uniformly dispersed in the form of short fiber and uniformly mixed with cement without developing fiber balls.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for introducing reinforcing fibers into a machine needle for kneading reinforcing fibers for reinforcing a hydraulic molded product such as concrete, which is a brittle material. .

<Conventional technology> Hydraulic molded products such as concrete have high compressive strength, are non-combustible materials, are durable, and are inexpensive, so they are consumed in large quantities as civil engineering and construction materials. It has the disadvantage of being extremely weak against Conventionally, steel fibers have been widely used as a means to compensate for these drawbacks, but various problems remain. For example, there are problems with rust and corrosion of steel, the danger of the fibers rebounding when sprayed, and the fact that the fibers are heavy and difficult to carry, requiring large equipment, especially when feeding them into a mixing machine. In order to solve this problem, PE (
Artificial organic fibers such as polyethylene (polyethylene), PP (polypropylene), and PVA (polyvinyl alcohol) have been developed, and PVA fiber in particular has been found to have excellent performance equivalent to or better than steel fiber.

<Problems to be solved by the invention> The following problems arose. In other words, if the fibers are fed into a kneading machine in an insufficiently dispersed state, the fibers tend to form fiber balls, have a small apparent specific gravity, and are difficult to handle in a narrow space.

Recently, among PVA fibers, short PVA fibers, which have extremely thick fineness, high strength, and Young's modulus, have been attracting attention for their reinforcing effect. In other words, a large number of rod-shaped objects are assembled with each one facing in a free direction, resulting in a three-dimensional lump), and it is uniformly and sufficiently dispersed in the kneading machine. The problem is that it is difficult to input. In order to solve this problem, we have arrived at the present invention as a result of intensive research into a method for easily feeding the reinforcing fibers into a kneading machine without causing poor separation.

Means for Solving the Problems> The present invention is a method for introducing reinforcing fibers that easily form into fiber balls and have a small apparent specific gravity into a kneading machine. That is, the present invention provides a method for dispersing and introducing into a material to be reinforced artificial organic fibers having a strength of 5 g/dr or more, a Young's modulus of 100 g/dr or more, a fineness of 100 to 5000 dr, and an aspect ratio of 30 to 2000. The group of artificial organic fibers carried by the belt conveyor is scraped off into almost short fibers by a rotor having a large number of protrusions on the surface, and the scraped short fibers are not retained. This is a method of introducing reinforcing fibers, which is characterized in that the reinforcing fibers are immediately introduced into the object to be reinforced.

The kneading machine to be used in the method of the present invention has already been put to practical use for kneading steel fibers into moxibustion, and there are various types of kneading machines such as two-wheel forced stirring type and tilting type. However, the method of the present invention can be used with any type of kneading machine and can easily be adapted to the specifications of the kneading machine.

As mentioned above, the reinforcing fibers targeted by the method of the present invention have a strength of 5 g/dr or more, a Young's modulus of 100 g/dr or more, a fineness of 100 to 5000 dr, and an aspect ratio of 30 to 30.
2000, and if the strength and Young's modulus are within the above range, the reinforcing effect will be fully exhibited, and if the fineness is less than 100 dr, it will be difficult to knead; If it exceeds it, the reinforcing effect will be poor. If the aspect ratio is less than 30, the fibers will be pulled out, resulting in poor reinforcement;
If it exceeds 0, the fiber separation will be defective. More preferably, strength is 8 g/dr or more, Young's modulus is 250 g/dr or more, fineness is 1500 to 3000 dr, and aspect ratio is 50 to 10 G.
Such artificial organic fibers can be uniformly dispersed using the method of the present invention, and particularly excellent results can be obtained.

The method of the present invention will be explained below with reference to the drawings. Fig. 1 is a plan view showing an example of the apparatus used in the method of the present invention, and Fig. 2 is an elevation view thereof. In these figures, l is a charging hopper, 2 is a raking rotor, 3 is a conveyor, and 4 is a A scraping rotor, 5 a suction side connection pipe, 6 a fiber sending fan, and 7 a discharge side connection pipe. Generally, the fibers are packaged in bags or cardboard cases and are placed into a feed hopper 1 or directly onto a conveyor belt. The shape of the charging hopper affects quantitative performance. If quantitative performance is important, it is better to have the hopper width closer to the conveyor and shallower. Usually, a hopper with a narrow lower part, such as those used for powder or granular materials, is not preferred. This is because, in the case of the fibers targeted by the method of the present invention, the fiber group tends to become clogged at the narrowed lower part. In order to further improve the quantitative accuracy, it is recommended to install a raking rotor 2 as shown in this figure. The raking rotor 2 rotates in the same direction as the conveyor belt and has the function of returning excess fibers to the rear of the conveyor belt, and is preferably provided with protrusions on the rotor surface so that the fibers are easily caught. The amount of supply at this time is determined by the size of the interval between the protrusion and the conveyor belt.

Incidentally, quantitative property can also be achieved by placing the fibers directly on the conveyor belt using human hands so that the thickness of the fiber group becomes almost uniform on the conveyor belt.

In addition to the device used in the method of the present invention, there is also a device for splitting the fiber group into almost short fibers, in which a blade rotating at high speed inside a drum using centrifugal force breaks apart the fiber clumps. Some have a structure in which the blades are rotated within a drum with a coarse mesh to break up the fibers, and the fibers are dropped from the gaps in the mesh. There is a structure in which a bar is swung in a chamber with a horizontal bar at the bottom to scrape fibers from the gaps between the horizontal bars.

All of these target steel fibers, and artificial organic fibers with significantly different specific gravity, physical properties, etc.
Even when used in these devices for steel fibers, favorable results cannot be obtained in terms of splitting properties and uniform dispersibility (temporally and areawise). The method of the present invention solves the problem of fiber separation and uniform dispersion by using the above-mentioned scraping rotor.

The scraping rotor used in the method of the present invention has a large number of protrusions on its surface, and uses the protrusions to scrape the fiber groups (clumps) carried by the conveyor belt downward, resulting in almost shorter fibers than the fiber lumps. It has the function of separating and dropping it to the bottom. It is preferable that the rotational speed of the Rogue is increased in accordance with the increase in throughput, that is, the speed of the feed conveyor. Usually, the rotation speed of the tip of the protrusion on the surface of the rogue is preferably 20 to 400 @ h < the speed of the conveyor belt, and the rotation direction of the rotor is preferably opposite to the rotation direction of the conveyor belt. The protrusions provided on the rotor surface should have a diameter of 1 to 3 mm - a length of 3 to 50 m.
Use a metal wire of 2 to 15 mm on the rotor surface.
It is preferable to install them at intervals. Alternatively, a metal band having protrusions may be wound around the rotor so that the protrusions stand on the surface of the rotor.

The scraped fibers must be thrown into the reinforcing material without being allowed to stagnate. For this purpose, for example, the scraped fibers must be immediately sent to a fiber feeding fan and then transported to a kneading machine via air feeding piping. A method of air transport and injection is used.

At this time, by changing the shape of the piping at the pneumatic feeding tip inputting section, that is, by changing the cross-sectional shape of the piping, it is possible to easily set the feeding state. Specifically, it is preferable to spread the input portion into a trumpet shape so that the fibers are uniformly scattered on the surface of the reinforcing material. Depending on the structure of the kneading machine, it is also possible to place a scraping rotor directly above the kneading machine and feed the fibers into the kneading machine by natural fall. Further, a dispersing device such as a centrifugal type or a one-way injector type may be provided below the scraping rotor, and the fibers may be introduced into the kneading machine. In any case, if the fibers remain for some time after being scraped off, they will become a fiber mass again, causing fiber balls. Therefore, it is most important to feed the fibers into the kneading machine in their original state. Although the method of the present invention was developed especially for PVA fibers, it can also be applied to organic fibers such as aramid, polypropylene, acrylic, etc. as long as they have the strength, Young's modulus, fineness, and aspect ratio described above.

BACKGROUND ART Conventionally, for the purpose of opening a fiber mass such as wool, a method has been generally used in which a fiber mass sent by a conveyor belt is opened using a device called a Fairnote. In this device, a large cylinder with many protrusions on its surface is surrounded by many small cylinders that also have a large number of protrusions, and the fiber mass moves back and forth between the large cylinder and the small cylinder by the rotation of these cylinders. The fiber mass is separated into small lumps or short fibers while passing from one side of the cylinder to the other. As is clear from this, the device used in the present invention and the device called Fairnote are completely different. When the above fair note is used in the method of the present invention,
The fibers are undesirably torn in the longitudinal direction and are subject to many scratches.

Figure 3 shows equipment added to the top of the equipment shown in Figure 2 to enable unmanned continuous operation, and Figure 4 is a side view of the equipment shown in Figure 3, viewed from the preparation side. be. In these figures, 12 is a weighing hopper, 13 is a storage conveyor, and 14
1 is a side cover, 15 is a raking beater, 16 is a weighing hopper bracket, and 17 is a balance weight.

In the case of operating the apparatus shown in FIGS. 1 and 2, the preparation work was carried out so that the thickness of each batch was almost the same, so a worker was always required for operation. However, with the apparatus shown in FIGS. 3 and 4, the storage capacity of the storage conveyor 13 allows a large number of batches to be operated continuously without any preparation work.

First, the input fibers are placed on the side cover 14 on the storage conveyor 13.
Fill it to the brim to prevent it from spilling. Next, when you press the operation start button, the storage conveyor 13 and the raking beater 15
rotates and the fibers are thrown into the weighing hopper 12. The weighing hopper 12 has an opening/closing damper built into its lower part. When the amount of fiber fed into the weighing hopper reaches a predetermined amount,
The storage conveyor 13 and the sweeping beater 15 are stopped, the weighing hopper damper is opened, and the weighed fibers fall into the preparation hopper 1. Next, the sweeping rotor 2, conveyor 3, sweeping rotor 4, and retirement fan 6 start rotating.

This device can also be operated in conjunction with the device described in FIGS. 1 and 2 or independently.

Furthermore, if a device for detecting the presence of fibers, such as a phototube, is attached to the charging hopper 1 and linked, it can also be used as a continuous mixer such as a hogger mixer.

Although various structures of the weighing hopper 12 can be considered, a balance weight type as shown in FIG. 4 is most preferable and inexpensive. Further, the traveling direction of the belt of the storage conveyor 13 is preferably substantially perpendicular to the traveling direction of the belt of the belt conveyor 3, as shown in FIGS. 3 and 4.

<Effects of the Invention> As described above, the present invention has practical advantages when the newly developed artificial organic fibers described above are used in hydraulic molded products in place of steel fibers. It is indispensable. For example, conventionally, 4
A loom separator is installed at the fiber inlet of the kneading machine, which is located at a height of about 300 m, and a person picks up the bags containing the fibers and manually loads them into the sifter in small quantities for operation. Although it was impossible to employ such a method in large-scale side sole construction, the present invention has made it possible to put it to practical use in such construction for the first time.

A practical example will be explained below.

Example 1 One of the latest tunnel construction methods is NATM (New Australian Tunnel Method). The method of the present invention was carried out at the construction site with the following specifications. At that time, the apparatus shown in FIGS. 1 and 2 was used.

Fiber specifications Material PVA fineness
1500dr Cut length 30am Strength 9g/dr Young's modulus 300g/dr Aspect ratio 70 Fiber feed amount 3kg/mi Mixing ratio
t vot% vs. Concrete Conveyor
300v x 1000(! 0.4kw scraped rotor φ400 x 30012 G, 7
5kw fiber sending fan 15m'/ll1
in
By attaching a stopper 11, it is easy to move and use.

In addition, the scraping rotor surface has a diameter of 3 mm and a length of 30 mm.
A+A steel wire is installed at 15m5+ pitch.

The pipe outlet (input part) from the retirement fan is widened in a trumpet shape so that the fibers are evenly distributed on the cement surface. Also, the speed of the conveyor belt is 1. Ota/la t
160 m/win was adopted as the rotational speed of the tip of the surface protrusion of the ns scraping rotor. The scraped fibers were scattered on the cement surface without stagnation.

As a result, the PVA fibers, which were in the form of fiber lumps, were evenly dispersed into short fibers and could be mixed uniformly into the cement without forming fiber balls.

Example 2 In Example 1, an apparatus was used in which the storage conveyor, weighing hopper, etc. shown in FIGS. 3 and 4 were installed on the apparatus shown in FIGS. 1 and 2, and the storage conveyor 900Wx 100OL 0.4kw and weighing hopper 250Wx 9007! Fibers were added to cement in the same manner as in Example 1, except that the operation was performed at x 400 h. The weight of the parts in FIGS. 3 and 4 other than the apparatus shown in FIGS. 1 and 2 is approximately 500 kg.

By using such a device, unmanned continuous operation is possible, and the uniform dispersion of fibers is also improved to the same level as in Example 1.
As well as being extremely good.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an example of an apparatus capable of carrying out the method of the present invention, and FIG. 2 is a side view. FIG. 3 is a side view of the apparatus shown in FIG. 2 which has been further improved, and FIG. 4 is a rear view of the apparatus shown in FIG. 3 as viewed from the preparation side. In the figure, each number indicates the following. ■, Preparation hopper 2. Scraping rotor 3
, conveyor 4. Scraping rotor 5
, Suction side connection pipe 6. Retirement fan 7, discharge side connection pipe 8. Operation panel 9, common frame 10
．． Wheel 11, stopper 12. Weighing hopper 13, storage conveyor 14. Side cover 15, raking beater 16. Weighing hopper bracket 17,
Balance weight 18. Support point 19, frame
Taiwan Patent Applicant RiRa Shi Co., Ltd.

Claims (1)

[Claims] 1. Strength is 5 g/dr or more, Young's modulus is 100 g/dr or more, fineness is 100 to 5000 dr, and aspect ratio is 30.
In a method of dispersing artificial organic fibers having a particle size of 2,000 to 2,000 in a material to be reinforced, the artificial organic fibers carried by a belt conveyor are placed on the top of the belt conveyor with a large number of protrusions on the surface. 1. A method for introducing reinforcing fibers, which comprises scraping off almost all short fibers with a rotor having a rotor, and immediately throwing the scraped short fibers into an object to be reinforced without allowing them to stagnate. 2. A weighing hopper is installed above the belt conveyor, and a storage conveyor is installed above it, and the fibers stored on the storage conveyor are fed into the weighing hopper almost quantitatively as artificial organic fibers on the belt conveyor. The reinforcing fiber charging method according to claim 1.