JPH07116840B2 - Spraying material transportation / spraying device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a device for transporting and spraying concrete spraying material. More specifically, the present invention relates to a concrete spraying material transporting / spraying device that enables uniform mixing of the spraying material and high-speed transportation and is excellent in economic efficiency and operability.

(Background Art) Conventionally, in order to prevent the collapse of the ground in tunnels, underground cavities, etc., concrete has been sprayed on the exposed surface of the ground.

In such a case, conventionally, concrete has been sprayed by the following method.

(1) Dry method Mixing concrete spray material other than water by kneading (dry mix), transferring to the spraying machine while mixing the quick-setting agent by the belt conveyor, and transporting the mixture by hose with compressed air from the compressor, Spraying is performed by mixing with the water supplied from the water pump at the nozzle part.

(2) Wet method Knead the concrete spray material in the front part (slump 0
The mixture is transferred to a spraying machine while mixing the quick-setting agent by a belt conveyor, the mixture is hose-transported by compressed air from the compressor, and the mixture is sprayed from the hose outlet.

Similarly, the whole mixture is mixed (slump 6-12 cm), transported by a truck mixer, and the mixture is hose-transported by a spraying machine concrete pump, and the quick-setting agent is separately hose-transported by the compressed air from the compressor at the outlet nozzle section. Both are mixed and sprayed.

A part of fine aggregate, coarse aggregate and, in some cases, a quick-setting admixture is also conveyed by a belt conveyor while kneading a part of water, cement and sand, transporting them to a mortar pump and transporting them from the mortar pump to a hose It is transferred to a dry spraying machine, and the hose is transported by compressed air from a compressor, and both are mixed and sprayed at the outlet nozzle.

However, in the case of these conventional spraying methods, there are some problems that should be improved immediately.

For example, in the conventional spraying method, the spraying machine to be used has a special structure, is expensive, and requires a considerable amount of skill in its operation in both the dry method and the wet method. there were. In particular, this spraying machine was difficult to uniformly mix the concrete spraying material and to efficiently transport the hose, and it was quite difficult for even a skilled person to operate the spraying machine.

Further, in the above dry method and wet method, a quick-setting agent (in some cases, addition of fiber etc.) is added on the belt conveyor, but in this method the kneading state is not good, so the spray material Was not satisfactory, and moreover, it was easy for troubles to occur during transportation.

Furthermore, in the wet method, the quick-setting admixture is stored in a tank and pressure-fed to the vicinity of the nozzle by a compressor, so the equipment is complicated, the maintenance of the machine and the cost are disadvantageous, and the pipe outlet part Since it is only mixed, the state of kneading of the spray material is poor.

For this reason, there has been a strong demand for uniform mixing of the concrete spraying material, high-efficiency and high-speed transportation, and further realization of a concrete spraying apparatus that is easy to maintain and operate and at low cost.

(Object of the Invention) The present invention has been made in view of the above circumstances and is capable of uniform mixing and high-speed conveyance overcoming the problems of the conventional dry and wet concrete spraying devices. Easy-to-maintain, easy-to-operate, low-cost and economical transportation of concrete spray materials
The aim is to provide a spraying device.

DISCLOSURE OF THE INVENTION In order to achieve the above object, a spray material transporting / spraying device of the present invention is provided with a spray pipe for circulating compressed air toward an outlet, and a concrete spray material connected to the spray pipe. Of the Coanda spiral flow generator, which sends all or a part of the above into the spray pipe and transports it toward the outlet of the spray pipe by the Coanda spiral flow.The Coanda spiral flow generator is a connection part to the spray pipe. From the circular tube of which the diameter gradually increases in the opposite direction, the circular slit of the bend of the right-angled or acute-angled bent wall facing the curved wall of the end of the cylindrical tube, and the concrete at the other end of this bent wall. With a spray material inlet, the inclination angle θ of the cylindrical tube, tan θ is 1/4 ~ 1/8,
Compressed air is blown out from the annular slit to generate a Coanda spiral flow, and by this Coanda spiral flow, the concrete spraying material is fed into the spray pipe,
It is characterized in that it is transported in the spray pipe.

The Coanda spiral flow generated in the spray pipe of the present invention is completely different from the conventional laminar flow or turbulent flow known as a concern about the motion of fluid, and is turbulent even under the motion condition of the fluid belonging to the turbulent flow region. It was found by the inventor of the present invention to be different from. Its generation has already been proposed by this inventor.

That is, the inventor of the present invention, when a vector in the pipe radial direction is added to the vector of the fluid in the pipe direction, swirls the fluid, and a dynamic boundary layer is formed near the inner wall of the pipe based on this swirling flow, and the fluid spirals We found the fact that it travels at high speed in the pipeline direction while drawing a (spiral). In such a Coanda spiral flow, the fluid travels at high speed,
Moreover, even if solid particles exist due to the existence of the dynamic boundary layer, they do not collide with the inner wall of the pipe as in the case of turbulent flow. Therefore, in the process of spiral motion of the fluid, the state of the fluid is kept uniform, and local alteration due to collision and contact with the inner wall is suppressed.

The present invention utilizes the Coanda spiral flow having such excellent characteristics.

The present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 shows an example of a concrete spraying material transporting / spraying apparatus of the present invention. In this example, a spraying machine is not used, which is completely different from the conventional method.
Moreover, no belt conveyor is used for mixing and transferring concrete spraying materials.

The Coanda spiral flow generator 1 is supplied with a mixture 2 prepared by kneading all of the concrete spraying materials supplied from a constant quantity feeder, a quick-setting agent, a dust reducing agent, steel or glass fiber, and steam 3 etc. To do. Further, compressed air from the compressor 4 is supplied to the Coanda spiral flow generator 1.
The admixture 2 and the additive 3 such as a quick-setting agent are transported through the spray pipe 5 by the Coanda spiral flow generated by the inflow of compressed air and sprayed from the outlet nozzle portion 6. This device can be advantageously used in both the dry type and the wet type, but in the dry type, water is supplied from the water pump 7 to the outlet nozzle portion 6 and mixed with the spray material.

FIG. 2 is a sectional view showing the Coanda spiral flow generator and the spray pipe used in this example.

External air is introduced into the spray pipe 5 through an air inlet 8. The air inlet 8 has a diameter larger than that of the spray pipe 5. Compressed air may be introduced from the air introduction port 8. Further, it is not always necessary to make the diameter larger than that of the spray pipe 5 as in this example.

The Coanda spiral flow generation device 1 is connected to the spray pipe 5.

This Coanda spiral flow generation device 1 has, for example, the following configuration.

The cylindrical pipe 9 is connected to the branch 10 of the spray pipe 5, and its diameter gradually increases in the direction opposite to the connecting surface. Compressed air is supplied to the cylindrical tube 9 from the lateral direction through an introduction tube 11. At this time, an annular slit 12 is provided for sending compressed air into the cylindrical tube 9 toward the outlet of the blowing tube 5. Further, a wall surface 13 that is smoothly curved is provided from the annular slit 12 toward the spray tube 5. A bent wall surface 14 bent at a right angle or an acute angle is provided on the side opposite to the curved wall surface 13, and the interval of the annular slit 12 between the curved wall surface 13 and the bent wall surface 14 can be freely adjusted. Also,
A distribution chamber 15 for uniformly supplying compressed air to the annular slit 12 is provided.

The concrete spraying material and additives are supplied to the introduction port 16 by a constant quantity supply feeder or the like.

Coanda spiral flow generator 1 having such a structure
In (1), the motion vector of the compressed air from the annular slit 12 and the motion vector of the external air introduced together with the concrete spraying material and the additive from the inlet 16 are combined to generate the spiral motion 17. In that case, at the outlet of the annular slit 12, the compressed air moves by drawing the streamline of the arrow α by the Coanda effect to form a dynamic boundary transfer near the inner wall of the pipe. Further, a large negative pressure region is generated on the inlet 16 side of the annular slit 12 to promote the inflow from the inlet 16.

FIG. 3 and FIG. 4 show another example of the Coanda spiral flow generation device.

In the case of FIG. 3, the introduction port 16 is formed by a cone body 18. In addition, in the case of FIG.
Introducing pipe 19 is provided. This introducing pipe 19 is used effectively for introducing a concrete spraying material, a specific component of an additive, and a specific component, such as steel fiber, may be pressure-fed through this introducing pipe 19, Alternatively, it may be supplied by means such as a screw feeder.

In the case of the apparatus shown in FIG. 2, for example, in the case of the apparatus shown in FIG. 2, the apparatus for transporting and spraying the sprayed material by generating the Coanda spiral flow has a compressed air pressure of ^{2 to} 10 kg / cm ² , preferably 4 to.
7 kg / cm ² , and the inclination angle θ of the cylindrical tube can be such that tan θ is about 1/4 to 1/8. For example, the inner diameter of the spray pipe 5 in FIG.
L ₁ is 65φ, the inner diameter L ₂ of the air inlet 8 of the spray tube 5 is 100φ,
By setting the inner diameter l ₁ of the branch pipe 10 to 28φ and the inner diameter l _{2 of the} inlet 16 to 100φ, a device using compressed air pressure of 4 to 7 kg / cm ² can be constructed. The transport distance by the Coanda spiral flow can be appropriately set to about 30 to 120 m, and the transport speed can be appropriately selected to about 20 to 150 m / sec.

Even if a spraying machine is not used as in the prior art, uniform mixing of spraying materials and high-speed transportation can be realized. Further, there is no trouble caused by the adhesion of the spray material to the wall of the spray pipe.

FIG. 5 shows another example of the device of the present invention. This example shows an example using a spraying machine.
An additive 3, for example, a binder, a dust reducing agent, a fiber, steam or the like is fed into the spray pipe 5 by the Coanda spiral flow generator 1, and the mixture 2 of other concrete spray materials is sprayed by a belt conveyor or the like. It is transferred to the machine 20 and transported in the spray pipe 5. Also in this case, the spray pipe 5
Coanda spiral flow is generated in. By this Coanda spiral flow, the additive 3 is transported and sprayed while being uniformly mixed with the admixture of the concrete spraying material.

FIG. 6 shows the installation relationship between the Coanda spiral flow generator 1 and the sprayer in the case of this example. From the spraying machine 20, compressed air and a concrete spraying material are supplied. The pressure in this case is 2-10 kg / cm ² ,
The mixing ratio is preferably 4 to 7 kg / cm ² , and the mixing ratio can be about 10 to 30. Of course, the present invention is not limited to the above example. It goes without saying that various modes are possible.

(Effects of the Invention) As described above, according to the present invention, the equipment can be transported and sprayed at a much lower cost and easier to operate than the conventional apparatus.

Since the kneading is carried out by the pressure source and the continuous quantitative kneading is carried out in a thin pipe, the kneading is more homogeneous and efficient than the kneading in the hopper of the spraying machine. Moreover, because of the Coanda spiral flow, there is no trouble due to the adhesion of the spray material into the pipe, and stable spraying at high speed is possible.

[Brief description of drawings]

FIG. 1 is an assembly layout diagram showing an example of the apparatus of the present invention. FIG. 2 is a sectional view of the Coanda spiral flow generator and the spray pipe. FIG. 3 and FIG. 4 are cross-sectional views showing examples of other Coanda spiral flow generators, respectively. FIG. 5 is an assembly layout diagram showing another example of the apparatus of the present invention, and FIG. 6 is a partial sectional view thereof. The numbers in the figure indicate the following. 1 ... Coanda spiral flow generator, 2 ... Concrete spraying material mixture, 3 ... Additive, 4 ... Compressor, 5 ... Spraying pipe, 6 ... Exit nozzle part, 7 ... Water pump, 8 ... … Air inlet, 9 …… cylindrical tube, 10 …… branching tube, 11 …… introduction tube, 12 …… annular slit, 13 …… curved wall surface, 14 …… bent wall surface, 15 …… distribution chamber, 16 …… Introduction, 17 …… Spiral motion

Continuation of the front page (56) References JP-A-56-124465 (JP, A) Photograph of the description and drawings attached to the application for Japanese Patent Application No. 59-108681 (No. 61-22561). Microfilm (JP, U) Microfilm (JP, U) taken from the contents of the specification and drawings attached to the application for Japanese Patent Application No. Sho 60-21882 (No. Sho 61-139762)

Claims (2)

[Claims] 1. A spray pipe for circulating compressed air toward an outlet, and a whole or a part of a concrete spray material fed into the spray pipe, which is connected to the spray pipe, and is directed toward the spray pipe outlet. The Coanda spiral flow generator consists of a cylindrical pipe that gradually increases in diameter in the opposite direction from the connection to the spray pipe, and the curved end of this cylindrical pipe. Having an annular slit between a right-angled or acute-angled bent wall surface facing the wall surface, and an inlet for the concrete spraying material at the other end of the bent wall surface, the inclination angle θ of the cylindrical pipe is tan θ is 1 / 4 to 1/8, and a Coanda spiral flow in which compressed air is blown out is generated from the annular slit, and this Coanda spiral flow causes the concrete to flow into the blowing pipe. A spraying material transporting / spraying device, characterized in that the spraying material is fed in and transported in the spraying pipe. 2. The spraying material transporting / spraying device according to claim 1, wherein fibers are used as an additive in the spraying material.