JPH03233099A - Dust collector for tunnel - Google Patents

Abstract

PURPOSE:To make ventilation of air highly polluted with dust possible by installing electric dust collectors in a dust-collecting chamber provided in an upper space of a tunnel partitioned with ceiling boards, and by providing nozzles on outlets of blowers for guiding of streams of cleaned air to outward and downward directions. CONSTITUTION:An upper space in a tunnel 11 is partitioned with ceiling boards 5 over a required length, and thereby a dust-collecting chamber 2 is formed. Two dust collectors 3 are installed in parallel in the dust-collecting chamber 2, and the chamber is partitioned with a partition wall 6 to form air drafts. Then two blowers 4 are installed on the discharge side 2b of the drafts. Nozzles 13 are provided to outlets 4a of the blowers 4 with blowing ports of the blowers placed facing downward and slightly outward off the centerline of the tunnel 1. By operation of the dust collectors 3, dusts in polluted air in a space 1a on a driveway is collected, and cleaned air is blown out in spiral streams through the nozzles 13. Thereby the polluted air in the space 1a over the driveway and the cleaned air from the dust collectors 3 are mixed in a short time, and ventilation can be accomplished satisfactorily.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a tunnel dust collection device that removes soot and dust inside a tunnel using an electrostatic precipitator and reuses the contaminated air inside the tunnel. Regarding dust collection equipment.

[Conventional technology]

There are several types of tunnel dust collectors, and representative ones include the bypass tunnel type shown in FIG. 8(A), and the ceiling installation type shown in FIG. 8(B) and FIG. 9. Here, FIG. 9(A) is a plan view of FIG. 8(B), and the same (
B) is a longitudinal sectional view thereof. In the bypass tunnel method, a bypass passageway is provided in tunnel 1 to form dust collection chamber 2, and dust collection chamber 2 is connected from the tunnel side wall.
The contaminated air introduced into the tunnel is purified by an electrostatic precipitator (hereinafter simply referred to as a dust collector) 3, and then blown out from the tunnel side wall into the tunnel l by a blower 4. On the other hand, in the ceiling installation method, the upper space inside the tunnel 1 is partitioned by a ceiling plate 5 to form a dust collection chamber 2 with one end 2a as an intake side and the other end 2b as an air supply side. The contaminated air introduced into the dust collection chamber 2 is purified by the dust collector 3,
Air is blown into the tunnel 1 again from the blower 4 placed on the air supply side 2b. The ceiling installation method has the advantage of low civil engineering costs because there is no need to excavate a bypass channel. In FIG. 9 showing the ceiling installation method, two dust collectors 3 are installed in the dust collection chamber 2 via a partition wall 6, and two dust collectors 3 are installed on the air supply side 2.
Two axial flow blowers 4 each having a cylindrical casing 4b are disposed at b. Therefore, the air in the upper space of the tunnel introduced linearly from the intake lower on the end face of the intake side 2a along the tunnel center line is purified by the dust collector 3, and then
It is blown out straight into the tunnel upper space from a again. The ceiling plate 5 also serves as a floor plate that supports equipment such as the dust collector 3 (as shown in the figure, this ceiling plate 5 is usually extended to just below the air outlet 4a of the blower 4, and is used for maintenance, etc.) It is used as a means of accessing the air blower 4.Although only two dust collectors 3 are installed in Fig. 9, if more dust collectors 3 are installed,
These are arranged from the intake side 2a toward the exhaust side 2b while sequentially shifting their positions in the lateral direction. By the way, in the dust collection device shown in FIG. 9, the end face of the intake side 2a of the dust collection chamber is opened to form an intake lower, but the end face is closed and an intake port is formed at one end of the ceiling plate 5. (hereinafter referred to as the upward suction type). FIG. 1O is a vertical cross-sectional view showing a schematic configuration of the above-mentioned upper suction type. A rectangular window-shaped intake port 9 is provided. Contaminated air within the tunnel 1, which is guided into the dust collection chamber 2 from the intake port 9 as shown by the arrow, is purified by the dust collector 3 and returned to the tunnel 1 by the blower 4.

[Problem to be solved by the invention]

However, conventional ceiling-mounted tunnel dust collectors have various problems as described below, which cause a decline in dust collection performance. SUMMARY OF THE INVENTION An object of the present invention is to provide a tunnel dust collection device that solves these problems and improves the air cleanliness inside the tunnel. First, in the conventional device, as shown in FIG. 9, purified air that has been purified by the dust collector 3 is blown directly into the upper space from the blower 4 along the center line of the tunnel 1. Therefore, compared to the bypass tunnel system, it is difficult for the purified air to mix with the contaminated air in the roadway space la, and generally a distance of about 100 m is required for complete mixing. As a result, there is a limit to the installation interval of dust collectors, and there is a problem that sufficient dust collection cannot be achieved in sections where the engine load of automobiles increases and the amount of contaminated air increases, such as on uphill slopes in undersea highway tunnels. Ta. Incidentally, the installation interval of the dust collectors is determined based on the distance at which purified air and contaminated air are completely mixed. Therefore, the first purpose of this invention is to shorten the distance required for mixing purified air and unpurified contaminated air, increase the number of dust collectors installed per unit length of a tunnel, and improve air cleanliness. Our goal is to provide tunnel dust collectors with improved performance. Next, in the conventional device, since the lower part of the blower 4 is covered with the ceiling plate 5, as shown in FIG. The merging of the air is obstructed, a vortex 12 is generated, resulting in energy loss, and a large amount of electric power is required to blow a predetermined amount of air. Accordingly, a second object of the present invention is to provide a tunnel dust collection device that facilitates the merging of air at the blower outlet to reduce power consumption. By the way, there is a limit to the installation space for dust collectors in tunnels due to civil engineering restrictions, and it is desired to increase the processing air volume as much as possible while minimizing the space required per station. Accordingly, the third object of the present invention is to provide a tunnel dust collection device in which (1) the processing air volume per station is increased by adding a device to the arrangement of the dust collectors. Furthermore, in the case of an upward suction type dust collector, the edge of the intake port 9 has conventionally been cut out at right angles to the plate surface, so that the dust collection chamber has been cut out, as shown in Fig. 11. The air sucked into the dust collector 2 tends to contract at the suction port 9, separate from the front and rear edges 9a and 9b, and concentrate in the center of the suction surface 3a of the dust collector 3. Therefore, dust collector 3 is 8
Only 5 to 90% of the capacity could be exhibited, and the pressure loss at the intake port 9 also reached 5 to 10%. Accordingly, a fourth object of the present invention is to provide a tunnel dust collector that improves dust collection efficiency by reducing flow concentration and pressure loss caused by separation at the intake port in an upward suction type dust collector. There is a particular thing.

[Means to solve the problem]

In this invention, an upper space in a tunnel is partitioned from a lower space by a ceiling plate to form a dust collection chamber with one end serving as an intake side and the other end serving as an air supply side, and an electrostatic precipitator is installed in this dust collection chamber. In addition, the tunnel dust collector in which a blower is disposed on the air supply side is configured as follows. In order to achieve the first objective, a nozzle is provided at the blower opening of the blower so that the blowing direction of purified air is directed slightly outward and downward with respect to the center line of the tunnel. Air blowers are usually used as a set of two, but in that case,
The solid angle between the tunnel center line and the air blowing direction is 5
It is preferable to set the angle to 12°. To achieve the second objective, the ceiling partition plate below the blower is eliminated and the blower casing is exposed to the space below the tunnel. In this case, if a ventilation scaffold is provided below the blower, it will be easier to access the blower during maintenance and inspection. In conventional tunnel dust collectors, it has been common practice to arrange the dust collector parallel to the longitudinal direction of the dust collection chamber in order to guide the air flow straight to the suction surface of the dust collector. On the other hand, in this invention, in order to achieve the third objective, the second and subsequent dust collectors are overlapped with the dust collector in front of them when viewed from the intake side of the dust collection chamber. Arrange diagonally to the longitudinal direction. At that time, the projected area of the leading dust collector with respect to the flow seen from the intake side is made smaller than that of the other dust collectors, and the distance between the leading dust collector and the second dust collector is set to be smaller than that of the other dust collectors. Making the distance larger than the interval between the dust collectors is effective in preventing a drop in the air volume distribution to the second dust collector. Furthermore, in such a dust collector, it is preferable to adjust the air volume of the dust dispenser by changing the opening degree of the damper on the outlet side of the dust dispenser. In order to achieve the fourth objective, in the upward suction type, two types of radius, large and small, are continuous from the lower edge to the upper edge of the near side edge of the intake port along the gradient of the air flow. At the same time, the rear edge opposite to this edge is continuously rounded with two types of radii, large and small, from the upper edge to the lower edge. Two types of radii for rounding the edge of the intake port are suitable, where t is the thickness of the ceiling partition plate, t to 3t is suitable for the large radius R1, and t15 to t/3 is suitable for the small radius R2.

[For use]

For the first purpose, by directing the purified air blowing direction slightly outward and downward from the center line of the tunnel, a swirling flow is generated within the tunnel space, which promotes mixing of purified air and contaminated air. do. For the second purpose, by eliminating the ceiling partition plate below the blower, the flow of air blown from the blower and the flow around its outer periphery are made parallel, facilitating their merging and preventing the generation of vortices. If necessary, ventilation scaffolding such as wire mesh, perforated steel plates, or metal gratings may be provided to provide access to the blower during maintenance and inspection. When arranging multiple dust collectors with their positions shifted horizontally from the intake side to the exhaust side of the dust collection chamber, stacking the front and rear dust collectors will allow you to maintain a fixed air path in the dust collection chamber. The effective air path area treated by the dust collector becomes wider compared to the area. On the other hand, if the front and rear dust collectors overlap, a problem arises in that the flow to the dust collector located at the rear is blocked by the dust collector located in front of it. Therefore, for the third purpose, as a result of repeated studies through experiments, we decided to arrange the second and subsequent dust collectors diagonally to the longitudinal direction of the dust collection chamber when viewed from the intake side of the dust collection chamber. It has been found that even if the front and rear dust collectors have a larger overlap than before, the flow to the rear dust collector will not be obstructed by the front dust collector. When tilting the dust collector, if the angle of inclination is too large, the air volume distribution of the dust supply engine will be uneven. According to experiments, if the inclination angle is 12 degrees or less and the distance between the front and rear of the dust collector is at least twice the width of the dust collector, the flow will be distributed almost evenly without the need for a special wind deflector. It has been found. Even in that case, the first dust collector faces the flow directly from the intake side and occupies a large area in the entire flow path of the dust collection chamber, so the air volume to the second dust collector immediately behind is reduced. death,
The effect tends to extend to the third or fourth dust collector. This is because the flow path area of the dust collection chamber is greatly reduced by the first dust collector, causing the flow to contract, and the flow separated in front of the second dust collector to the third and even fourth dust collectors. This is to go to the dust collector. In order to solve this problem, the projected area of the first dust collector for the flow should be made smaller than that of the other dust collectors, and the distance between the first and second dust collectors should be made smaller than the distance between the other dust collectors. to prevent separation and direct the flow to the second dust collector. The distance between the first and second dust collectors (dimension 0 in FIG. 4) is preferably at least 1.5 times the flow diameter on the intake side of the dust collection chamber. Furthermore, fine adjustment of the flow to the dust dispenser is performed by changing the opening degree of the damper on the exit side of the dust collector. For example, if you reduce the opening of a damper, the air volume of that dust collector will decrease, and the flow will be diverted to other dust collectors accordingly. A damper is also installed on the inlet side of the dust collector, but if the inlet damper is closed, the flow passing through the electrode plate will be biased and the dust building efficiency will decrease, so it is better to adjust the opening of only the outlet damper. Good. For the fourth purpose, the edges of the front side of the intake port and the opposite rear side of the intake port are rounded with 1112 different radii in succession. By providing a gradient in the flow direction, separation of the flow at this edge is suppressed, and the resulting pressure loss is also reduced.

【Example】

Now, an embodiment of the present invention in a dust collector for a highway tunnel will be described based on FIGS. 1 to 7. In all the embodiments described below, the same reference numerals are used for parts that are the same as or correspond to those of the conventional example. FIG. 1 shows a first embodiment of the present invention, in which FIG. 1(A) is a plan view, FIG. 1(B) is a vertical cross-sectional view, and FIG. - It is a sectional view along line C. The upper space of the tunnel 1 that communicates with the left and right sides of the figure is partitioned by a ceiling plate 5 over a required length to form a dust collection chamber 2. The left end of the dust collection chamber 2 in the figure is an intake side 2a, and the right end is an air supply side 2b. Inside the dust collection chamber 2, two dust collectors 3 are arranged on the left and right so that they are slightly spaced apart, and the air passages through which contaminated air flows through them are separated from each other by a partition wall 6. On the air supply side 2b, two axial flow type blowers 4 each having an impeller housed together with a drive motor in a cylindrical case song are arranged so as to pass through each of the above-mentioned ventilation paths along the center line of the tunnel 1. It is located. A nozzle 13 is provided at the air outlet 4a of the blower 4 to determine the direction of air blowing.
The air outlet is oriented slightly outward and downward relative to the tunnel centerline. In such a configuration, when the dust collector is operated,
Contaminated air in the roadway space la is led to the dust collection chamber 2 from the intake lower at the end face of the intake side 2a, where soot and dust are removed by the electrostatic precipitator 3 to become purified air, which is then returned to the roadway space from the nozzle 13 of the blower 4. is blown out. Since the purified air from the nozzle 13 is directed outward and downward with respect to the tunnel center line as shown by the solid line arrow, this purified air flows into a pair of spiral secondary flows as shown by the broken line arrow within the roadway space la. (swirling flow). As a result, the purified air blown out from the nozzle 13 entrains the contaminated air in the roadway space la and mixes with it in a short time. As a result of a demonstration test, it was confirmed that according to the above configuration, the distance at which purified air and contaminated air are completely mixed is approximately 10% shorter than that of the conventional method. Figure 2 shows an application of this invention to a single blower (jet fan) 4 placed in the middle of a dust collector in order to promote mixing of purified air and contaminated air. By directing the blown air outward and downward and creating a swirling flow shown by the broken line, the mixing efficiency can be increased and the capacity of the jet fan 4 can be made smaller than before. According to the above configuration, the purified air blown out from the blower 4 generates a swirling flow in the roadway space la, compared to the conventional structure in which the purified air is simply blown out along the center line to the upper layer of the roadway space 1a. Mixing of purified air and contaminated air is promoted, and the installation interval of dust collectors can be shortened from about 100 m to about 90 m. FIG. 3 shows a second embodiment of the invention, and FIG. 3(A)
is a plan view of the dust collection chamber, and (B) is a longitudinal sectional view thereof. In the figure, the ceiling plate 5 that partitions the dust collection chamber 2 ends at a connection part with the blower 4, and the cylindrical casings 4b of the two blowers 4 are exposed below. As a result, as shown in the figure, the air flow 11 on the outer periphery approaches the air flow 10 blown from the blower 4 almost parallel to it, and the two smoothly merge without creating a vortex. therefore,
The energy loss associated with the mixing of the two flows 10.11 is smaller than before. In addition, if necessary for maintenance and inspection of the blower 4, as shown in the figure, if a ventilation scaffold 14 made of, for example, a wire mesh is provided below the blower 4, the air flow 11 from the lower space 1a can be obstructed. It is possible to maintain the same workability as before. 4 and 5 show a third embodiment of the invention. First, FIG. 4(A) is a plan view of the dust collection chamber, and FIG. 4(B) is a sectional view of the tunnel along line B-B. in this case,
In the dust collection chamber 2, six dust collectors 3 (3A to 3F) are sequentially shifted in position in the lateral direction and arranged from the air intake side 2a to the air supply side 2b. 15 is a partition that connects the dust collectors 3, 16 is a partition that connects the first and sixth dust collectors 3A and 3F and the side wall of the dust collection chamber 2, and these partitions 15 and 16 pass through the dust collectors 3. This is to separate the contaminated air before passing through and the purified air after passing through. Also,
17 is a guide wall for guiding the flow to the dust collector 3F. Among the six dust collectors 3, the leading dust collector 3A has a smaller projected area for the flow than the others when viewed from the intake side 2a, and the dust collector 3A has a smaller projected area with respect to the flow than the others. is set up. On the other hand, the second and subsequent dust collectors 3 (
3B to 3F) are installed obliquely with respect to the longitudinal direction of the dust collection chamber 2 so as to partially overlap the dust collector 3 in front of each of them. Here, the tilt angle α of the dust collector 3 is
is set to 10 degrees except for the dust collector 3F, and only the dust collector 3F is set to 5 degrees. In addition, the distance between the first dust collector 3A and the second dust collector 3B can be made larger than the distance d between the second and third dust collectors by providing a non-sloping part of length S on the partition wall 15. It is. In such a configuration, contaminated air introduced into the dust collection chamber 2 from the roadway space 1a of the expressway tunnel 10 through the intake lower opening at the end face of the intake side 2a is evenly distributed to the dust collector 3 as shown by the solid line arrow. The air is distributed, and the soot and dust are removed by the famous confectionery dust machine 3 to become purified air, which is blown out from the blower 4 into the roadway space 1a as indicated by the broken line arrow. The effective air path area of the dust collector 3 in Figure 4 is the sum of the areas of the air suction surfaces of each of the six dust collectors 3, but the dust collectors 3 are arranged deeply one on top of the other as shown in the figure. Therefore, the total is about 20% larger than before. In other words, the amount of air processed per station of ventilation equipment increases accordingly. Since the second and subsequent dust collectors 3 are arranged diagonally with respect to the longitudinal direction of the dust collection chamber 2, even with the above-mentioned shape, the flow continues along the partition wall 6 from the famous confectionery dust collectors 3B to
Approximately evenly distributed among the 3Fs. In that case, since the first dust collector 3A occupies a large area in the flow path of the dust collection chamber 2, if the projected area for the flow is equal to that of the other dust collectors 3B to 3F, it is indicated by the arrow in Figure 6. As shown, the flow separates from the partition wall 15, producing a 'ia flow, and passes over the second dust collector 3B to the third dust collector 3C.
Begins to head towards. Therefore, as shown in FIG. 4, the first dust collector 3A is made smaller to suppress the occurrence of contracted flow, and the gap is increased to direct the flow toward the dust collector 3B. It has been confirmed through experiments that it is sufficient that the distance is at least 1.5 times the flow diameter of the suction side 2a of the dust collection chamber 2. Now, in order to further finely adjust the distribution of the flow to the confectionery dusting machines 3 arranged as shown in FIG. 4, the opening degree of the outlet damper of the famous confectionery dusting machine 3 is changed as described below. FIG. 5 is a horizontal sectional view showing a schematic plan configuration of the dust collector 3, in which 18 is an inlet damper, 19 is a charging section, 20 is a dust collecting section,
21 is an exit damper. The soot and dust particles in the contaminated air guided into the dust collector 3 through the artificial damper are charged by the charging section 19 to which a high voltage from the high voltage generator 22 is applied. The dust is captured by the dust collector 20 to which a high voltage is applied. The purified air from which soot and dust has been removed flows out through the outlet damper 21. Soot and dust deposited on the charging section 19 and the dust collecting section 20, and the air blow pipe 2
The compressed air blown out from 4 and 25 is used to blow it off at any time. The inlet and outlet dampers 18 and 21 rotate around vertical opening and closing shafts 18a and 21a, respectively, to open and close the front and rear of the dust collector 3. When the opening degree of the damper 18 or 210 becomes smaller, the resistance of the dust collector 3 to the flow increases, and the air volume of the dust collector 3 decreases. The reduced air volume is directed to other dust collectors 3. In that case, the inlet damper 18 is fully opened and the opening degree of the outlet damper 21 is adjusted to balance the flow rate of the famous confectionery machine 3. If the opening degree of the inlet damper 18 is made small, the flow when passing through the electrode plate of the dust collection section 20 will be biased, and the dust collection efficiency will be reduced. Therefore, it is preferable to adjust the damper only on the exit side. In order to evenly distribute the flow to the confectionery dusting machine 3, there is a method of forcibly distributing the flow by installing a guide vane 26 as shown in Fig. The effects are complex and optimal design is difficult. Moreover, excessive design has many restrictions, such as an increase in the load on the blower 4 (FIG. 4). In this respect, there is an advantage that the adjustment of the flow rate by the outlet damper 21 does not affect the flow of other dust collectors 3. FIG. 7 is a vertical cross-sectional view of a main part of an upper suction type dust device showing a fourth embodiment of the present invention. In the figure, along the air flow indicated by the arrow, the front edge 9a of the intake port 9 has two consecutive radii: R1 at the lower edge and R2 at the upper edge (R1>RZ). Further, the rear end edge 9b facing the end edge 9a is rounded with two consecutive large and small radii, R1 at the upper edge and R2 at the lower edge. As a result, the flow of contaminated air flowing into the dust collector 2 is limited to the edge 9.
It is sucked diagonally upward along the slopes of a and 9b, and separation and associated contraction flow do not occur. This flow flows into almost the entire surface of the suction surface 3a of the dust collector 3, contacts the not-illustrated electrode plate of the dust collector 3 without any waste, and is efficiently collected. Moreover, the pressure loss at the intake port 9 is also minimized.

【Effect of the invention】

According to this invention, the following effects can be obtained. By installing a nozzle in the blower's air outlet that directs the purified air slightly outward and downward from the center line of the tunnel, the distance required for mixing the purified air from the dust collector with the contaminated air in the tunnel space can be reduced. is shorter, the number of dust collectors installed per unit length of the tunnel can be increased compared to the conventional method, and sufficient ventilation is possible even in tunnels with high soot and dust concentrations. By exposing the blower casing to the lower space inside the tunnel, energy loss at the blower outlet is reduced, so the operating power of the blower is reduced by 1 to 5 liters compared to conventional methods.
% reduction. In that case, a ventilation scaffold can be provided below the blower if necessary. When multiple dust collectors are arranged from the intake side to the air supply side of the dust collection chamber by shifting their positions in the horizontal direction, by partially overlapping the dust collectors and arranging them diagonally, The effective air path area increases, and the amount of air processed per station of ventilation equipment can be increased without increasing the installation space for dust collectors. In addition, by making the first dust collector smaller and making the interval between the first and second dust collectors larger than the distance between other dust collectors, highly uniform flow distribution to the famous confectionery dust collector can be achieved. Furthermore, by adjusting the opening degree of the outlet damper of the famous confectionery machine, fine adjustment of the flow rate becomes easy. In an upward suction type dust collector, the front edge of the intake port is large from the lower edge to the upper edge. J) By continuously rolling two types of radii, and by continuously rolling two types of radii, large and small, on the rear edge opposite this edge from the upper edge to the lower edge, it is possible to Flow separation is improved, concentration of flow to the center of the dust collector suction surface and pressure loss are reduced, and dust collection efficiency is improved by 10 to 15%.

[Brief explanation of drawings]

FIG. 1(A) is a plan view of the first embodiment of the present invention.
Figure (B) is a cross-sectional view of the joint, and Figure 1 (C) is Figure 1 (B).
2 is a longitudinal sectional view of an applied example of this invention, and FIG. 3 (A) is a plan view of a dust collection chamber in a second embodiment of this invention. (B) is its longitudinal cross-sectional view;
FIG. 4(A) is a plan view of a dust collection chamber in the third embodiment of the present invention, FIG. 4(B) is a sectional view of the tunnel along line B-B, and FIG. FIG. 6 is a horizontal sectional view showing a schematic plan configuration of the dust collector, FIG. 6 is a plan view of the main part of the dust collection chamber to explain the flow of air in the dust collection chamber, and FIG. 7 is a fourth embodiment of the present invention. FIG. 8(A) is a perspective view showing a general example of a bypass tunnel type tunnel dust collector, FIG. 8(B) is a perspective view of a ceiling installation type, and FIG. A) is a plan view of Fig. 8(B), Fig. 9(B)
) is a longitudinal sectional view thereof, FIG. 10 is a longitudinal sectional view showing a general schematic configuration of an upper suction type dust collector, and FIG. 11 is a longitudinal sectional view of a main part thereof. be. DESCRIPTION OF SYMBOLS 1...Tunnel, 2...Dust collection chamber, 2a...Intake side, 2b...Air supply side, 3...Dust collector, 4...Blower, 4b...Casing, 5 ...ceiling board, 7,9
...Intake port, 13...Nozzle. Figure 3 Figure 8 Figure 1

Claims (1)

[Claims] 1) The upper space in the tunnel is partitioned from the lower space by a ceiling plate to form a dust collection chamber with one end serving as an intake side and the other end serving as an air supply side, and an electrostatic precipitator is formed in this dust collection chamber. At the same time, in a tunnel dust collector with a blower installed on the air supply side, a nozzle is installed at the blower opening of the blower to direct the direction of purified air blowing out slightly outward and downward with respect to the center line of the tunnel. Features of tunnel dust collection equipment. 2) Separate the upper space in the tunnel from the lower space with a ceiling plate to form a dust collection chamber with one end as the intake side and the other end as the air supply side, install an electrostatic precipitator in this dust collection chamber, and install the What is claimed is: 1. A tunnel dust collector in which a blower is disposed on the air supply side, the casing of the blower being exposed to a lower space within the tunnel. 3) The tunnel dust collection device according to claim 2, further comprising a ventilation scaffold provided below the blower. 4) Separate the upper space in the tunnel from the lower space with a ceiling plate to form a dust collection chamber with one end as the intake side and the other end as the air supply side, and install multiple electrostatic precipitators horizontally within this dust collection chamber. In the tunnel dust collection device, the electrostatic precipitators are arranged from the intake side to the exhaust side with their positions sequentially shifted in the direction, and a blower is arranged on the air supply side, and the second and subsequent electrostatic precipitators are arranged as viewed from the intake side. A tunnel dust collector characterized in that each tunnel dust collector is arranged obliquely to the longitudinal direction of a dust collection chamber, overlapping with an electric dust collector in front of the tunnel dust collector. 5) In the apparatus according to claim 4, the projected area of the first electrostatic precipitator with respect to the flow when viewed from the intake side is smaller than that of other electrostatic precipitators, and the area between the first electrostatic precipitator and the second electrostatic precipitator is A tunnel dust collector characterized in that the distance between an electrostatic precipitator and the other electrostatic precipitators is larger than the distance between other electrostatic precipitators. 6) The tunnel dust collector according to claim 4 or 5, wherein the air volume of each electrostatic precipitator is adjusted by changing the opening degree of the outlet damper of each electrostatic precipitator. Device. 7) Separate the upper space in the tunnel from the lower space with a ceiling plate to form a dust collection chamber with one end as the intake side and the other end as the air supply side, and install an electrostatic precipitator in this dust collection chamber, and In a tunnel dust collection device in which an air intake port is provided on the air intake side of the ceiling board and a blower is placed on the air supply side, the front edge of the air intake port is extended from the lower edge to the upper edge along the gradient of the air flow. It is characterized in that two types of radii, large and small, are continuously rounded, and the rear edge opposite this edge is continuously rounded with two types of radii, large and small, from the upper edge to the lower edge. Tunnel dust collector.