JP2544372B2 - Local dust removal method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a local dust removal method. More specifically, the present invention relates to a method for effectively removing dust locally or where air pollution due to dust in a non-nel or a construction site is significant.

(Background Art) Conventionally, a large fan has been commonly used for ventilation and dust removal in a sealed space such as a construction site in a tunnel or in a locally contaminated area due to dust.

However, depending on the method of using such a fan, the ventilation and dust removing capacity of the fan are not so large, and conversely the required power is large, so that the cost burden is considerable. For this reason, air pollution due to dust cannot be effectively suppressed by the conventional fan method, and there is a need for immediate improvement from the viewpoint of the health and safety of construction workers.

In order to deal with such a problem, a method of forcibly suctioning and removing dust-contaminated air with pressurized air has been proposed in recent years, and an apparatus therefor has been put into practical use.

The jet flow device (d) shown in FIG. 7 is an example thereof, in which a compressed air inlet slit (a) is provided in the vicinity of the suction port (a) and the compressed air is discharged through the discharge port (a). C), the dust air is sucked and forcibly discharged from the suction port (a) by the negative pressure generated by the ejector effect. With this device, which is known in detail, pressurized air of 1 to 7 kg / cm ² is sent from the inlet slit (a), and dust contaminated air is removed by the generated jet flow. are doing.

FIG. 8 illustrates the case where this device is used in a cleaning system in a tunnel. In this system, air contaminated by dust generated at tunnel construction sites is blown backward by a jet flow device (d), collected by a duct (e), and cleaned by a dust collector (f). It is carried out.

In the case of such a jet flow device (d) and the dust removal method using the same, dust locally at the face such as the face of a tunnel is much smaller and more efficient than the conventional fan system. Although it can be done, the dust removing effect is still insufficient, and there are the following problems to be overcome.

That is, in the method using this jet flow device (d), as is clear from FIG. 7, the taper is expanded from the inlet slit (b) of the pressurized air toward the outlet (c). Since the velocity near the inner wall surface was the largest and the velocity at the center was small, the air pressure loss was extremely large, and the dust discharge capacity was greatly limited. In fact, the actual distance that the dust is blown from the discharge port (c) is only about 20 m. Moreover, at distances longer than this, as is apparent from the system shown in FIG. 8, the air contaminated with dust is widely dissipated, and the air region contaminated with dust is rather expanded. And the collection to the duct (e) is only limited.

It is also conceivable to connect the discharge port (c) and the duct (e) by a conduit. However, in the case of this jet flow device (d), since the velocity is high near the inner wall surface due to its structure, dust easily attaches to the pipe wall, and air contaminated by a large amount of dust is collected in the dust collector (f). It is difficult to transport the material to the pipe wall, and dust is in contact with the pipe wall, so that the pipe wall is significantly worn and inevitably damaged. Therefore, in reality, it is impossible to use the pipeline.

It is conceivable to arrange multiple ducts (e) or increase the diameter of the ducts (e), but in this case, suctioning the dust collector (f) and collecting dust through the filter are extremely heavy loads. Therefore, a large dust collector for collection is required, and the cost for installing and operating it is also large.

Therefore, instead of the conventional method as described above, high efficiency in a local area near the concrete spray nozzle or the tunnel excavator, such as a confined space where the air pollution due to dust is remarkable, and a small measure at low cost. It has been strongly desired to realize an improved new local dust removal method capable of dust removal.

(Object of the Invention) The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a new local dust removal method that improves the drawbacks of the conventional methods and is more efficient.

DISCLOSURE OF THE INVENTION In order to achieve the above object, the present invention arranges a Coanda spiral flow generation device in the vicinity of a concrete spray nozzle or a non-nel excavator, and generates dust-contaminated air to the Coanda spiral flow generation device. Concrete spray nozzle or tunnel, characterized in that it is conveyed in a pipeline by a Coanda spiral flow generated by the inflow of compressed air of the above and is guided to a dust collecting water tank or a dust collecting shower tank to remove dust contaminated air. A local dust removal method in the vicinity of an excavator is provided.

Explaining in more detail below, "Coanda spiral flow", which is a concept relating to the flow of fluid used in the present invention, is completely different from laminar flow or turbulent flow known as a conventional fluid motion concept. It has been found by the inventor of the present invention that it is essentially different from turbulent flow even though it is under the motion condition of the fluid belonging to the flow region. And the method for its generation has already been proposed by the present inventor.

That is, the inventor of the present invention, when the vector in the pipe radial direction is added to the fluid vector in the pipe axial direction, the fluid swirls,
We have found that a dynamic boundary layer is formed near the inner wall of the pipe based on this free swirling flow, and the fluid travels at high speed in the pipe direction while drawing a spiral. Such a Coanda spiral flow is essentially different from a forced vortex flow and is generated without giving a force for swirling. The fluid travels at high speed, and even if solid particles are present due to the presence of the dynamic boundary layer, they do not collide with the inner wall of the pipe as in the case of turbulence. For this reason, in the course of the spiral motion of the fluid, the state of the fluid is uniformly maintained, and local deterioration due to collision or contact with the inner wall is suppressed. Also, the wear of the inner wall of the pipe is controlled.

Such excellent properties are extremely useful as a chemical or physical unit process, or a system thereof, including transportation of fluids such as particles, slurries and fibrous substances.

The inventor of the present invention has described the generation of a Coanda spiral flow having such excellent features, for example,
A device as shown in Figure 1 of the accompanying drawings has already been proposed.

In the example shown in FIG. 1, the Coanda spiral flow generator (1) is connected to the pipe (2), and the cylindrical pipe (3) connected to the pipe (2) is in the opposite direction. The diameter is gradually increasing toward it. Into a cylindrical tube (3),
Laterally through the inlet tube (4), pressurized fluid, eg
Introduce a compressed stream of gas, air, or liquid. An annular slit (5) is provided to pump this pressurized fluid in the direction of the conduit (2). Further, a wall surface (6) that is smoothly curved is formed from the annular slit (5) toward the conduit (2).

A bent wall surface (7) bent at a right angle or an acute angle is provided on the side opposite to the curved wall surface (6). The annular slits (5) are arranged such that their intervals can be adjusted freely. Furthermore, a distribution chamber (8) for uniformly supplying the pressurized fluid to the annular slit (5) is provided.

The end face opposite to the conduit (2) is an inlet (9), and the fluid can be introduced through this inlet (9).

In the Coanda spiral flow generator having such a structure, the motion vector of the pressurized fluid from the annular slit (5) and the motion vector of the fluid from the inlet (9) are combined to generate a spiral motion (10). . At that time, at the outlet of the annular slit (5), the pressurized fluid moves in a streamline along the arrow α by the Coanda effect to form a dynamic boundary layer near the inner wall surface of the conduit. Further, a large negative pressure region is generated on the inlet side (9) side of the annular slit (5), which promotes the inflow of fluid from the inlet port (9).

The shape in the vicinity of the annular slit (5) of such a Coanda spiral flow generating device is not limited to that shown in FIG. 1, and is, for example, FIG. 2, FIG.
As shown in FIGS. 4 and 5, various shapes can be used. From the annular slit (5), the pressurized fluid is
Smooth curved wall (6) so that it draws streamline α and flows
And the bent wall surface (7) having a right angle or an acute angle may form the annular slit (5).

The present invention uses the above Coanda spiral flow and its generation device to perform local dust removal on contaminated air that locally contains a large amount of dust generated near a concrete spray nozzle or a tunnel excavator.

As shown in FIG. 6, in the method of the present invention, for example, a Coanda spiral flow generation device (11), a pipe line (12) connected to this device, and a collection pipe connected to this pipe line (12). Use a dust tank (13) or a dust shower tank. The Coanda spiral flow generator (11) is placed near the concrete spray nozzle or tunnel excavator as described above, and the strong negative pressure generated at its inlet (15) causes air contaminated with a large amount of dust. Is sucked, and is conveyed in the pipe line (12) to the dust collecting water tank (13) or the dust collecting shower tank by the Coanda spiral flow.

Since the long-distance transport is possible at a high flow velocity of 120 m / s, for example, the length of the pipeline (12) is several tens of meters to 200 m.
It can be installed up to about m. The pressurized air for generating the Coanda spiral flow in the method of the present invention is 1 kg / cm ² to 1 from the pressurized air inlet (14) which is the annular slit of the Coanda spiral flow generator (11).
Send in the range of 0 kg / cm ² . Of course, there is no particular limitation on this pressure.

The dust collecting water tank (13) can have an extremely simple structure. The dust collecting water tank (13) can have various types and structures, and may be collected by a shower type dust collecting shower tank. It does not require a large dust collector unlike the conventional method.

This means that the in-pipe transfer of air contaminated with dust by the Coanda spiral flow is excellent in the transfer capacity of dust particles due to the spiral flow and also prevents the re-aggregation of the particles, so that the water in the water tank or shower tank is not This is because the separability due to the contact of, that is, the dust collection effect is good.

The dust collecting effect of the method of the present invention is extremely excellent in a local space such as a tunnel excavation site, a tunnel concrete spraying site, a ship hold, a factory, or the like, where contamination by dust is significant.

In particular, a remarkable local dust-removing effect can be obtained by mounting it in the vicinity of a spray nozzle of a concrete spray robot, a tunnel excavator, etc., which has not been an effective means until now. Of course, it should be pointed out that the invention is capable of various embodiments in details.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a Coanda spiral flow generation device. 2, 3, 4, and 5 are partial cross-sectional views showing an example of the slit portion of this device. FIG. 6 is a cross-sectional view illustrating the apparatus configuration for the method of the present invention. FIG. 7 and FIG. 8 are a sectional view and a front view showing a conventional device. The numbers in the figure indicate the following. 1 ... Coanda spiral flow generator 2 ... Pipe line 3 ... Cylindrical pipe 4 ... Introducing pipe 5 ... Slit 6 ... Curved wall surface 7 ... Bent wall surface 8 ... Distribution chamber 9 ... Inlet port 10 ... … Spiral motion 11 …… Coanda spiral flow generator 12 …… Pipeline 13 …… Dust collection tank 14 …… Pressurized air inlet 15 …… Inlet

Claims (1)

(57) [Claims] 1. A Coanda spiral in which a Coanda spiral flow generator is arranged in the vicinity of a concrete spray nozzle or a tunnel excavator, and dust-contaminated air generated is generated by feeding pressurized air into the Coanda spiral flow generator. A local dust removal method in the vicinity of a concrete spray nozzle or a tunnel excavator, which conveys a dust in a pipeline by a flow and guides it to a dust collection water tank or a dust collection shower tank to remove dust contaminated air.