JPH0233886Y2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> This invention relates to a concrete spray nozzle, and particularly relates to an improvement of a fiber-reinforced concrete spray nozzle.

<<Prior Art and Problems>> As is well known, concrete has a high compressive strength, but a very low tensile strength.

Therefore, in recent years, reinforcing fibers such as short fibers such as alkali-resistant glass fibers and carbon fibers have been mixed into concrete to increase its tensile strength.

On the other hand, in the tunnel construction method, for example, concrete is sprayed as a lining for the excavated surface, and if this lining concrete reinforcing fiber is mixed, effects such as the ability to reduce the spraying thickness can be obtained.

However, when reinforcing fibers are mixed into concrete and sprayed in advance, the specific gravity of the reinforcing fibers and the concrete constituent materials is greatly different, so it is easy to form a ball-shaped mass of only the reinforcing fibers, resulting in variations in strength. There were problems such as the hoses used to transport these items becoming clogged.

Therefore, when mixing reinforcing fibers with this type of lining concrete, the concrete and reinforcing fibers are transferred separately and mixed when sprayed with a spray nozzle.

As a spray nozzle, a double-pipe structure was exclusively used, with an inner pipe located in the center that spouted reinforcing fibers, and an outer pipe located around the inner pipe that spouted concrete concentrically. , I had the following problem.

That is, with a simple double-pipe structure, a blind spot for concrete flow occurs within the outer pipe, and concrete may accumulate and solidify during spraying.

As a result, the concrete spout is partially blocked, reinforcing fibers adhere to this area and gradually grow, and the concrete spouting speed varies, making it difficult to obtain good spraying conditions.

This problem can be solved by making the spout of the outer tube larger, but if it is made larger, a large amount of mist will be ejected from the upper part of the spout, and lump-shaped concrete will be ejected from the lower part, making it impossible to achieve a homogeneous spraying condition.

This idea was devised in view of the above-mentioned conventional problems, and it allows the solidifying material such as concrete to be smoothly ejected without stagnation in the pipe, and can be sprayed in a homogeneous state mixed with reinforcing fibers. An object of the present invention is to provide a spray nozzle for fiber-reinforced concrete.

《Means for solving the problem》 In order to achieve the above object, this invention has an inner tube placed in the center from which reinforcing fibers are ejected, and a tube placed around the inner tube to solidify mortar, etc. A spray nozzle having a double-tube structure consisting of an outer tube for ejecting material, characterized in that compressed air is injected through a space separated within the outer tube.

<<Operation/Effect>> In the spray nozzle having the above configuration, the blind spot in the outer tube disappears due to the flow of compressed air injected from the space and the flow of the solidifying material, and the solidifying material is smoothly jetted, increasing the jetting speed. In addition, the reinforcing fibers ejected from the inner tube at the center are uniformly diffused, and a good spraying condition is obtained.

<<Embodiments>> Hereinafter, preferred embodiments of this invention will be described in detail with reference to the accompanying drawings.

1 and 2 show an embodiment of the spray nozzle for fiber-reinforced concrete according to this invention.

The spray nozzle 10 shown in the figure has an inner tube 12 disposed at the center and ejects reinforcing fibers A, and is disposed around the outer circumference of the inner tube 12 so as to surround this, and has a reduced diameter at the tip and is used to spray concrete, mortar, etc. It is based on a double tube structure consisting of an outer tube 14 that spouts out the solidifying material B, and the reinforcing fibers A and the solidifying material B are transported separately, and mixing them when jetting them is different from the conventional nozzle. is the same as

The spray nozzle 10 shown in the figure has the following features.

That is, the solidifying material B protruding into the outer tube 14
transport pipe 16 and the tip nozzle part 14a of the outer pipe 14.
A ring material 18 having a U-shaped cross section with a larger diameter than the outer tube 14 is fixed between the outer tube 14 and the outer tube 14 to form an annular space 20. A plurality of through holes 22 are bored in the hole.

Compressed air C is injected into the annular space 20 via an injection pipe 24 .

In the spray nozzle 10 configured as described above, reinforcing fibers A such as short glass fibers are fed into the inner tube 12 using compressed air, and the solidifying material B is introduced into the outer tube 14 via the transport tube 16 using a pump or the like. When performing pressure feeding and spraying work, compressed air C is also sent into the annular space 20 via the injection pipe 24.

The pressure of the compressed air C is adjusted appropriately so that the solidifying material B sprayed from the spray nozzle 10 does not bounce excessively.

This compressed air C, together with the transfer speed of the solidified material B, prevents the solidified material B from stagnation in the outer tube 14 and smoothly moves the solidified material B to the tip nozzle portion 14a.

Therefore, unlike the conventional double pipe structure, the tip nozzle part 14a is not partially blocked by the solidifying material B, and the ejection state does not vary as in the case where the nozzle part 14a has a large diameter. A homogeneous spraying condition can be obtained without occurrence of.

FIG. 3 shows another embodiment of this invention, and only its features will be described below.

That is, in this embodiment, the space 20 is separated by a partition wall 26 fixed to the rear end 14b of the outer tube 14, and a plurality of through holes 22 are formed in the partition wall 26.

Even with the spray nozzle 10' formed in this manner, the same effects as in the above embodiment can be obtained.

Note that the ring material 18 shown in FIG.
Even if it is provided between the rear end portion 14b of 4 and the transport pipe 16, the same effect can be obtained.

<<Effects of the invention>> As explained above in detail in the examples, the spray nozzle for fiber-reinforced concrete according to this invention has excellent effects such as being able to spray reinforcing fibers and solidifying material in a homogeneous mixed state. is obtained.

[Brief explanation of drawings]

FIGS. 1 and 2 show an embodiment of this invention, with FIG. 1 being a cross-sectional view thereof, and FIG. 2 being a cross-sectional view taken from FIG. 1. FIG. 3 is a sectional view showing another embodiment of this invention. 10... Spray nozzle, 12... Inner pipe, 14...
Outer pipe, 16... Transport pipe, 18... Ring material, 20
... Space, 22 ... Through hole, 24 ... Injection pipe,
26... Partition wall, A... Reinforcing fiber, B... Solidifying material,
C...Compressed air.

Claims (1)

[Claims for Utility Model Registration] (1) Two pipes consisting of an inner tube disposed at the center from which reinforcing fibers are ejected, and an outer tube disposed surrounding the inner tube from which a solidifying material such as mortar is ejected. A spray nozzle for fiber-reinforced concrete, characterized in that the spray nozzle has a double-pipe structure and is formed by injecting compressed air through a space separated within the outer pipe. (2) The spray nozzle for fiber-reinforced concrete according to claim 1, wherein the space is formed in an annular shape around the outer circumference of the outer tube. (3) The spray nozzle for fiber-reinforced concrete according to claim 1, wherein the space is separated from the rear end of the outer tube.