JPH0127792B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION For example, in the primary lining of tunnel excavation work, when shotcrete is applied to a wall immediately after excavation, dust such as rock sand generated by the collision between the wall and the shotcrete can be removed. This invention relates to a dust collector for shotcrete construction that collects dust.

In recent years, as a construction method for tunnel excavation work, based on the idea of effectively utilizing the strength of the ground to maintain the stability of the tunnel, shotcrete, rock bolts, and steel supports have been used for the primary lining of the wall immediately after excavation. A method is provided for constructing a tunnel structure that is integrated with the ground by appropriately using supporting materials such as concrete.

By the way, when performing shotcrete construction using this construction method, a large amount of dust such as rock sand is generated at the construction site due to the collision of the shotcrete with the wall surface, especially when the construction site is a closed space. As a result, the dust concentration becomes extremely high, leading to a problem of deterioration of the working environment.

Conventionally, measures to remove the above-mentioned dust include adding dust-reducing agents to shotcrete, increasing the ventilation capacity of ventilation equipment installed at appropriate locations in tunnels, and Methods such as installing a fixed dust collector at a concrete construction site at a predetermined distance from the concrete spraying equipment have been adopted.

However, although the dust reduction method using the above-mentioned dust generation reducing agent can be expected to be effective to some extent, the effect has a limit and has not been able to improve the working environment. In addition, increasing the ventilation capacity of ventilation equipment and fixed dust collectors are effective in tunnels with small cross-sections, but in tunnels with large cross-sections, the dust spreads over a wide space and the treatment range becomes wider, making the equipment difficult to use. It has the drawback of being large and expensive, making it impractical.

This invention was made in view of the above circumstances, and its purpose is to efficiently remove dust generated when shotcrete collides with a wall surface during shotcrete construction in tunnel excavation work, etc. It is an object of the present invention to provide a dust collector that can collect dust, can be miniaturized, can be obtained at low cost, and can prevent deterioration of the working environment due to the dust, and its features are as follows: A dust trap is provided near the concrete spraying nozzle, and the dust is sucked through the dust trap immediately after the dust is generated.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a concrete spraying apparatus equipped with a dust collector for shotcrete according to the present invention. The concrete spraying device A is a device that travels inside a tunnel with a vehicle body 1 and sequentially applies shotcrete. The vehicle body 1 travels by driving a caterpillar 3 through wheels 2, and a machine frame 5 is attached to the front end of the vehicle body 1 via a rod 4, and this machine frame 5 is attached to a cylinder 8. This allows it to be raised and lowered in the vertical direction. An arm 6 is attached to the tip of the machine frame 5 by a cylinder (not shown) so as to be rotatable in the vertical direction about an axis in the longitudinal direction. An arm 7 is mounted so as to be movable. Furthermore, a spray nozzle attachment 10 is rotatably attached to the tip of the arm 7, and a spray nozzle 11 is attached to the spray nozzle attachment 10. A pipe (not shown) is attached to the spray nozzle 11, and this pipe is connected to a concrete storage tank and compressor (not shown) mounted on the vehicle body 1. Concrete and compressed air are supplied to the spray nozzle 11 in a mixed state.

A dust collection hood 12 is attached to the spray nozzle 11, the details of which are shown in FIGS. 2 and 3. The dust collecting hood 12 has an outer portion 13 and an inner portion 14 each having a substantially conical shape, and the proximal ends thereof are attached to a spray nozzle. A suction tube 15 is provided near the base end of the outer portion 13. A hollow portion 16 is formed between the outer portion 13 and the inner portion 14, and the tip portion is an opening portion 16a. In this case, the opening 16a is located above the opening 11a of the spray nozzle 11. On the other hand, the vehicle body 1 is equipped with a suction electric blower 18 (suction section). This suction electric blower 18 has a filter built therein, and has a mechanism for removing dust and releasing clean air when air containing dust is inhaled from the suction pipe 19. Suction pipe 15 provided on the outer side 13 of the dust collection hood 12
and a suction pipe 1 provided in the suction electric blower 18.
Between 9 and 9 is a bellows-shaped flexible tube 17.
is provided.

In the above configuration, the dust collection hood 12, the flexible tube 17, and the suction electric blower 18
constitutes a dust collector.

Next, the operation of the device having the above configuration will be explained.

First, the concrete spraying device sprays a mixture of compressed air and concrete onto the tunnel wall through the spray nozzle 11 while moving the vehicle body 1 sequentially to perform shotcrete construction. . At this time, the suction electric blower 18 is also started at the same time as the concrete spraying device is started. By the way, when performing shotcrete construction, a large amount of dust is generated due to collision between the shotcrete and the wall surface. Here, the dust collector collects the dust from the opening 16a of the hood 12 near the wall surface by using the suction force of the suction electric blower 18. The dust is guided from the dust collection hood 12 through the flexible tube 17 into the suction electric blower 18, and is removed by a filter built into the suction electric blower 18.

In this way, during the construction of shotcrete in a tunnel, the dust generated by the collision between the shotcrete and the wall surface is directly collected by the opening of the dust collection hood near the wall surface.
Since it is removed by a filter in the suction electric blower, it is possible to maintain a good working environment.

Further, FIGS. 4 and 5 are diagrams showing another embodiment of the present invention.

To explain Figures 4 and 5, 11
is a concrete spraying nozzle for concrete spraying equipment. This spray nozzle 11
is provided with an ejection tube 25 inside near the tip, whose diameter gradually decreases toward the tip and opens at the tip.
Furthermore, the opening 2 of the ejection pipe 25 of the spray nozzle 11
A plurality of suction holes 24 are provided near 5a. On the other hand, 20 is a dust collection hood, which consists of an outer part 21 and an inner part 22 each having a truncated conical shape. The base end 21a of the outer part 21 is attached near the lower end of the suction hole 24 of the spray nozzle 11, and the base end 22a of the inner part 22 is attached near the upper end of the suction hole 24. . A hollow portion 23 is formed between the outer portion 21 and the inner portion 22, and the tip thereof is an opening 23a.

In this case, the opening 23a is the spray nozzle 1.
It is located above the opening 11a of No. 1.

Next, the operation of the device having the above configuration will be explained.

First, the concrete spraying device sprays a mixture of compressed air and concrete from the spray nozzle onto the tunnel wall surface, similar to the previous embodiment, to perform shotcrete construction. At this time, the area around the opening 25a of the jet pipe 25 provided inside the spray nozzle 11 becomes under negative pressure due to the passage of the shot concrete. Due to this negative pressure, air in the hollow part 23 of the dust collection hood 20 and air in the vicinity of the opening 23a are sucked through the suction hole 24. As a result, the dust near the wall surface is sucked together with the induced air from the opening 23a of the dust collection hood 20, and is further mixed with shotcrete and sprayed onto the wall surface.

In this way, during the construction of shotcrete in a tunnel, the dust generated by the collision between the shotcrete and the wall is sucked into the vicinity of the wall through the opening 23a of the dust collection hood 20, and further through the suction hole 24. It is mixed with shotcrete and sprayed onto the wall. This action is repeated continuously. This action allows dust to be collected without spreading into the tunnel, maintaining a good working environment. According to this embodiment, since there is no need for a suction device as shown in FIG. 1, there is an advantage that the device can be made smaller and lighter.

As explained above, according to the present invention, since the dust trap having a hollow interior and an opening at the tip is provided near the spray nozzle of the concrete spraying device, shotcrete construction in, for example, tunnel excavation work is possible. When performing this, the dust generated by the collision between the shotcrete and the wall surface can be collected near the wall surface. This prevents dust from spreading, so it is possible to maintain a good working environment. Moreover, it has the advantage that the device can be made smaller and lighter, and the device can be provided at a lower cost. In particular, according to the present invention, the dust collecting hood serving as the dust trapping body has a double structure in which the inside is hollow, and the outside air containing dust is sucked from the opening around the tip of the hood. The outside air sucked in from the nozzle forms an annular uniform laminar flow (cylindrical air curtain) near the opening toward the opening. The collected dust is trapped by the annular uniform laminar flow toward the opening and is difficult to escape from the dust collection hood, resulting in an extremely good suction effect. Furthermore, since the tip opening of the dust collection hood is set at a position that protrudes beyond the tip of the nozzle, this also has the effect of further improving the dust suction effect. In addition, since the dust collection hood has a structure in which an inhalation opening is provided around the tip, even if the diameter of the dust collection hood is increased to expand the dust trapping area, the outside air containing dust can still be absorbed. The suction force may not be greatly reduced, but rather the dust suction efficiency can be improved by expanding the trapping area.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a concrete spraying device equipped with a dust collector for shotcrete construction according to the present invention, and Fig. 2 is a vertical cross-section of the main part of the dust collector for shotcrete construction shown in Fig. 1. FIG. 3 is a plan view of the same, FIG. 4 is a vertical sectional view of a main part showing another embodiment of the present invention, and FIG. 5 is a plan view of the same. A... Concrete spraying device, 11... Spraying nozzle, 12, 20... Dust collection hood (dust trapping body), 16, 23... Hollow part, 16a, 23a...
...Opening part, 18...Electric blower for suction (suction part),
24... Suction hole (suction part).

Claims (1)

[Claims] 1 A concrete spraying device is equipped with a dust collection hood that protrudes from around the vicinity of the tip of a spray nozzle and is formed to surround the nozzle with the nozzle as the center, and the dust collection hood has an inner part and an outer part. As a result, the dust collection hood is formed into a double structure with a hollow interior and an opening around the tip, and the opening is located at a position that projects beyond the tip of the nozzle. for,
A dust collector for shotcrete construction, characterized in that the device is equipped with a suction section for applying negative pressure to the hollow section and suctioning outside air containing dust from an opening at the tip.