Dustproof device for observation device

Abstract

To provide a dustproof device capable of ensuring visibility of an observation device even in an environment with a lot of flying debris.SOLUTION: A dust prevention device 10 of an observation device 5 comprises a translucent panel 11 provided at the front part of the observation device 5, a first nozzle 12 that surrounds the panel and forms an airflow flowing forward, and a second nozzle 13 that forms an airflow that flows in a layer along a front surface 11a of the panel 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a dust prevention device for an observation device. [Background technology]

[0002] When installing observation devices such as observation sensors and observation cameras, a cover is generally attached to protect the observation devices. Patent Document 1 discloses a protective cover structure that can be fixed to the object to be installed without reducing the strength of the object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-35695 Summary of the Invention [Problem to be solved by the invention]

[0004] In environments with a lot of dust and other flying debris, the debris easily adheres to the cover, hindering observations by the observation device. An example of such an environment is the work space inside a tunnel under construction. Tunnel construction using the NATM (New Austrian Tunnelling Method) method involves spraying large amounts of concrete onto the excavation surface. During this work, the observation device monitors the condition of the sprayed concrete. However, large amounts of dust generated during excavation float around inside the tunnel, and some of the concrete sprayed onto the excavation surface bounces back. When placed in such an environment, the dust and concrete quickly adhere to the cover of the observation device, hindering observations.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a dustproof device that can ensure the visibility of an observation device even in an environment with a lot of flying debris. [Means for solving the problem]

[0006] A dustproof device for an observation device according to one embodiment of the present disclosure comprises a translucent panel disposed in front of the observation device, a first nozzle that forms an airflow that surrounds the panel and flows forward, and a second nozzle that forms an airflow that flows in a layer along the front surface of the panel.

[0007] The opening of the first nozzle may extend to surround the panel when viewed from the front and open forward. The opening of the second nozzle may be located on one side of the front surface of the panel when viewed from the front and open from one side to the other side of the front surface. The opening of the first nozzle may be located rearward of the panel. A gap may be formed between the first nozzle and the panel when viewed from the front. The first nozzle may be located outside the region located downstream of the second nozzle when viewed from the front.

[0008] The dustproof device may further include a window provided in front of the panel. In this case, the second nozzle may open in a part of an inner circumferential surface that forms the window. The window may include an inclined surface located on the inner circumferential surface at a position facing the second nozzle across the panel, and the inclined surface may be inclined so that the further away from the second nozzle the inclined surface is, the more forward it is positioned.

[0009] The dust prevention device may further include a visor portion provided on a side of the panel where the second nozzle is located and extending forward. The amount of gas ejected per unit time from the second nozzle may be set to a value between 1 / 11 and 1 / 9 of the amount of gas ejected per unit time from the first nozzle. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a dustproof device that can ensure the visibility of an observation device even in an environment with a lot of flying debris. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic perspective view of a dust prevention device according to an embodiment of the present disclosure; [Figure 2] FIG. 2 is a side view of the dustproof device according to the embodiment. [Figure 3A] FIG. 2 is a front view of the dustproof device according to the embodiment. [Figure 3B] FIG. 3B is a front view of a modified example of the dust prevention device shown in FIG. 3A. [Figure 4] 10A to 10C are front views of some examples of openings according to the present embodiment. [Figure 5] FIG. 1 is a cross-sectional view of an example in which a dustproof device according to an embodiment of the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present disclosure will be described below. Note that common parts in each drawing are assigned the same reference numerals, and redundant explanations will be omitted. For ease of explanation, mutually orthogonal directions, X, Y, Z, circumferential direction CD, and radial direction RD, are defined. The X and Z directions are parallel to a horizontal plane, and the Y direction is a vertically downward direction. The Z direction is the extension direction of the central axis 1, which is the reference axis of the dust prevention device 10 according to this embodiment, and is also the extension direction of the observation direction and optical axis of the observation device 5 to which the dust prevention device 10 is attached. Note that the central axis 1 and the optical axis of the observation device 5 may or may not coincide with each other. The reference axis of the circumferential direction CD and radial direction RD is the central axis 1.

[0013] Furthermore, "front" refers to one side in the Z direction (the front right side in FIG. 1), and "rear" refers to the other side in the Z direction (the rear left side in FIG. 1). Furthermore, "up" refers to one side in the Y direction (the upper side in FIG. 1), and "down" refers to the other side in the Y direction (the lower side in FIG. 1). "Viewed from the front" means, for example, when looking rearward from any position on the central axis 1 (i.e., in the opposite direction to the Z direction).

[0014] The dust prevention device 10 according to this embodiment is attached to an observation device 5 (see FIG. 1). The dust prevention device 10 protects the optical system 6 (see FIG. 1) of the observation device 5 from flying debris such as dust, while ensuring the visibility of the observation device from the flying debris. The observation device 5 is an optical device with a predetermined viewing angle, such as an imaging device such as a video camera. The observation device 5 and the dust prevention device 10 are intended for use in an environment where there is a lot of flying debris such as dust. Such an environment is, for example, inside a tunnel under construction. The observation device 5 is installed inside the tunnel with the dust prevention device 10 attached, and observes, for example, the condition of concrete being sprayed onto the excavation surface (for example, the spraying position and amount, etc.).

[0015] Fig. 1 is a schematic perspective view of a dust prevention device 10 according to an embodiment of the present disclosure. Fig. 2 is a side view of the dust prevention device 10. Fig. 3A is a front view of the dust prevention device 10. Fig. 3B is a front view of a modified example of the dust prevention device 10 shown in Fig. 3A.

[0016] As shown in Fig. 1, the dustproof device 10 is attached to the observation device 5 so as to cover the optical system 6. The dustproof device 10 is attached to the observation device 5 using, for example, fixing parts such as bolts or bands, or a predetermined attachment (not shown). Alternatively, the dustproof device 10 may be provided with a housing (not shown). In this case, the housing (not shown) houses the observation device 5, and the observation device 5 is held stably inside it.

[0017] The dust prevention device 10 according to this embodiment includes a panel 11, a first nozzle 12, and a second nozzle 13. As shown in Fig. 2, the first nozzle 12 is connected to a gas supply device 16 via a supply adjustment unit 14. The second nozzle 13 is connected to the gas supply device 16 via a supply adjustment unit 15.

[0018] The gas supply device 16 is composed of a compressor, a gas cylinder, a blower, or the like, and supplies gas to each of the first nozzle 12 and the second nozzle 13. The gas is, for example, air. The supply adjustment unit 14 and the supply adjustment unit 15 are each composed of, for example, a well-known pressure reducing valve and a speed controller.

[0019] As shown in FIG. 1 , the first nozzle 12 is provided on a first member 17. The panel 11 and the second nozzle 13 are provided on a second member 18. The first member 17 and the second member 18 are connected to each other by fastening parts (not shown) such as screws, and their relative positions are fixed. The panel 11, the first nozzle 12, and the second nozzle 13 may each be provided on separate structures, or two of them and the remaining one may each be provided on separate structures. Alternatively, they may be provided on a single structure.

[0020] The first member 17 is an annular member extending in the circumferential direction CD with the central axis 1 as the reference. The first member 17 has a width in the radial direction RD that is at least large enough to form the first nozzle 12, and its inner diameter is set to a value equal to or larger than the outer dimensions of the second member 18. If the inner diameter of the first member 17 is larger than the outer dimensions of the second member 18, an annular gap 19 is formed between the second member 18 and the first member 17. In this case, the first member 17 is connected to the second member 18 via connecting portions (not shown) scattered around the second member 18.

[0021] The first nozzle 12 has an opening 12a as a gas outlet. The opening 12a extends in the circumferential direction CD so as to surround the panel 11 when viewed from the front, and opens forward. As shown in Fig. 3A, the opening 12a is formed, for example, in an annular shape extending over the entire area in the circumferential direction CD.

[0022] The opening 12a is a slit (slot) through which pressurized gas is accelerated and ejected. To obtain an ejection at a desired speed, the width of the opening 12a along the radial direction is set to, for example, about 0.1 to 0.5 mm. However, as long as an airflow ejected at a desired speed can be obtained, the width of the opening 12a is not limited to the above value.

[0023] The opening 12a may be located at approximately the same position as the panel 11 in the Z direction, or may be located several centimeters (for example, 1 cm) behind the panel 11 (see FIG. 2). The airflow 20 ejected from the first nozzle 12 generates negative pressure around the first nozzle 12 and moves forward while drawing in gas. By positioning the opening 12a a predetermined distance behind the panel 11, the airflow 20 passes near the panel 11, decelerating by that distance. In other words, the reduction in flow velocity alleviates the pressure drop near the panel 11, and it is possible to suppress the intrusion (suction) of flying debris radially inward (into the vicinity of the panel 11) due to the negative pressure.

[0024] Furthermore, the above-described gap 19 may be formed between the first nozzle 12 and the panel 11 when viewed from the front. The gap 19 is an annular space formed between the second member 18 and the first member 17, and penetrates the first nozzle 12 in the Z direction. When the gap 19 is formed, gas flows from the rear to the front through the gap 19. As a result, the pressure drop that occurs radially inward of the first nozzle 12 is alleviated by the inflow (supply) of gas from the gap 19. Therefore, it is possible to suppress the intrusion (suction) of flying debris radially inward (in other words, near the panel 11) due to negative pressure.

[0025] As shown in Fig. 3B, the openings 12a may be formed in a portion of the entire area extending in the circumferential direction CD. That is, when viewed from the front, the first nozzle 12 (openings 12a) may be located outside a region 22 located downstream of the second nozzle 13 (lower in Fig. 3B). The region 22 is the region that the second nozzle 13 looks out over, and in the example shown in Fig. 3B, it is formed by a trajectory (in other words, an extended region) when the cross-sectional shape of the openings 13a is virtually moved in the Y direction. This region 22 is approximately equal to the region through which the airflow 21 ejected from the second nozzle 13 flows.

[0026] 3B extends in the circumferential direction CD from one side to the other in the X direction above the panel 11 in a region other than the region 22. That is, the openings 12a are located on the left, upper, and right sides of the panel 11 when viewed from the front. The length of the openings 12a along the circumferential direction CD is set to a value equal to or greater than half the circumferential length of the openings 12a when they are formed over the entire area of the circumferential direction CD.

[0027] FIG. 4 is a front view of several examples of the openings 12a. For ease of explanation, the openings 12a are shaded in black. The opening 12a shown in FIG. 4(a) is a single slit extending continuously in the circumferential direction CD. This slit may be located at the center of the width direction of the first member 17 along the radial direction RD, or may be shifted radially outward or radially inward from the center. The shape of the openings 12a is not limited to the shape shown in FIG. 4(a). For example, as shown in FIG. 4(b), the openings 12a may be multiple (e.g., two) slits extending concentrically in the circumferential direction CD at intervals in the radial direction RD. The openings 12a may be scattered in the circumferential direction CD in the region where the openings 12a are formed. For example, the openings 12a may be configured by multiple round holes (see FIG. 4(c)) or multiple elongated holes (see FIG. 4(d)) arranged at intervals along the circumferential direction CD.

[0028] The second member 18 is a disk-shaped member that has a predetermined thickness in the Z direction and is perpendicular to the central axis 1. The second member 18 has a window portion 23 that opens forward. The window portion 23 is provided in front of the panel 11 and functions as an observation window for the observation device 5. The shape of the window portion 23 is arbitrary as long as it allows for the desired observation. For example, the window portion 23 is formed in a rectangular shape with sides in the X and Y directions.

[0029] The panel 11 is a light-transmitting flat plate and is provided in front of the observation device 5 (optical system 6). The panel 11 protects the optical system 6 from foreign matter such as flying debris, and also guides the flow of the airflow 21 ejected from the second nozzle 13. The panel 11 is made of a material such as transparent glass or resin.

[0030] The second nozzle 13 is located on one side of the front surface 11a of the panel 11 when viewed from the front. The second nozzle 13 has an opening 13a as a gas outlet. The opening 13a extends in one direction and opens from one side of the front surface 11a to the other. In the example shown in FIG. 1, the second nozzle 13 is provided on the front and upper side of the panel 11 and extends in the X direction. Furthermore, the second nozzle 13 opens from the upper side of the panel 11 to the lower side (i.e., in the Y direction).

[0031] Like the opening 12a, the opening 13a is a slit (slot) with a rectangular cross section that accelerates and ejects gas to which a predetermined internal pressure has been applied. To obtain an ejection at a desired speed, the width of the opening 13a along the Z direction is set to, for example, about 1 to 2 mm. However, as long as an airflow ejected at a desired speed can be obtained, the width of the opening 13a is not limited to the above value.

[0032] On the other hand, the length of opening 13a along the X direction is set to a value equal to or greater than the width of panel 11 exposed through window portion 23. This length is determined by the width of window portion 23 along the X direction, and is, for example, about 50 mm. Note that, like the width of opening 13a, this length is not limited to the above-mentioned value.

[0033] The second nozzle 13 may open to the inner peripheral surface 23a of the window portion 23. That is, the opening 13a may be formed on the inner peripheral surface 23a. In this case, the inner peripheral surface 23a of the window portion 23 may include an inclined surface 23b. The inclined surface 23b is located at a position facing the second nozzle 13 (opening 13a) across the panel 11, and extends so that the further away from the second nozzle 13 it is, the more forward it is positioned. The inclined surface 23b may be a flat surface or a curved surface.

[0034] Next, an example of the operation of the dustproof device 10 will be described using Figure 2. In this description, it is assumed that the observation device 5 is observing the front. The dustproof device 10 is attached to the observation device 5, and the panel 11 is positioned in front of the optical system 6. The second nozzle 13 is positioned above the panel 11, and the opening 13a is positioned approximately horizontally and opens downward. On the other hand, the first nozzle 12 opens forward.

[0035] The gas supply device 16 supplies gas to each of the first nozzle 12 and the second nozzle 13. The internal pressure of the first nozzle 12 and the amount of gas supplied to the first nozzle 12 are adjusted by a supply adjustment unit 14. The internal pressure of the second nozzle 13 and the amount of gas supplied to the second nozzle 13 are adjusted by the supply adjustment unit.

[0036] When the internal pressure of the first nozzle 12 increases, gas is ejected from the opening 12a. As described above, the opening 12a opens forward and extends to surround the panel 11. Therefore, the gas ejected from the first nozzle 12 forms an airflow 20 that flows forward while surrounding the panel 11. In other words, the first nozzle 12 forms a hollow, cylindrical airflow 20 with the panel 11 located inside, and blows away debris flying toward the panel 11 forward.

[0037] The internal pressure of the first nozzle 12 is set to a value that will provide an ejection volume that will allow the airflow 20 to blow the debris forward. For example, assuming that the debris is relatively heavy, such as concrete slag (paste), the internal pressure of the first nozzle 12 is set to 0.5 MPa, which will provide an ejection volume per unit of approximately 200 L / min. By setting the ejection volume to this value, debris flying toward the dust control device 10 can be blown forward.

[0038] On the other hand, when the internal pressure of second nozzle 13 increases, gas is ejected from opening 13a. As described above, opening 13a is positioned horizontally above panel 11 and opens downward. Therefore, the gas ejected from second nozzle 13 forms a layered airflow 21 that flows downward along front surface 11a of panel 11. In other words, second nozzle 13 blows away flying debris toward panel 11 downward.

[0039] The internal pressure of the second nozzle 13 is set to a value that allows the airflow 21 to blow away the scattered objects downward. However, the airflow 21 flows radially inside the airflow 20 ejected from the first nozzle 12. Therefore, it is considered that most of the scattered objects that reach the airflow 21 have collided with the airflow 20.

[0040] For example, if the flying matter is slag, it can be assumed that the flying matter reaching the airflow 21 is relatively small slag that has broken up upon collision with the airflow 20. Therefore, the internal pressure of the second nozzle 13 is set to a value that will provide an ejection volume sufficient to blow such relatively small flying matter downward. However, if the ejection volume per unit of the airflow 21 is excessively increased, the negative pressure generated by the airflow 21 will induce unnecessary drawing in of the flying matter. Taking these factors into consideration, the ejection volume of the gas from the second nozzle 13 is set to a value smaller than the ejection volume of the gas from the first nozzle 12. Specifically, for example, the pressure is set to 0.15 MPa, which provides an ejection volume per unit of approximately 15 L / min. In this way, the ejection volume of the gas from the second nozzle 13 per unit time is set to a value between 1 / 11 and 1 / 9 of the ejection volume of the gas from the first nozzle 12 per unit time.

[0041] As described above, in this embodiment, airflow 20 first collides with the flying debris, and then airflow 21 collides with the flying debris that has entered radially inward of airflow 20. Therefore, even in an environment with a lot of flying debris, adhesion of the flying debris to panel 11 can be suppressed, and the visibility of observation device 5 can be ensured.

[0042] When the window portion 23 is provided in front of the panel 11, the inner peripheral surface 23a (see FIG. 1) of the window portion 23 is located on the opposite side from the second nozzle 13. When the inclined surface 23b is formed on this inner peripheral surface 23a, the airflow 21 can be guided smoothly downward without being disturbed.

[0043] 3B, when opening 12a of first nozzle 12 is not formed below panel 11, airflow 21 flows downward without colliding with airflow 20. This prevents the two airflows from colliding, thereby preventing vortexes from being generated and preventing unwanted entrainment of debris by the vortexes. Furthermore, by omitting the formation of airflow 20 below panel 11, the amount of gas consumed can be reduced, and the weight of dust prevention device 10 can also be reduced.

[0044] The amount of gas ejected from the second nozzle 13 is set to a necessary and sufficient value that is smaller than the amount of gas ejected from the first nozzle 12. This allows the amount of gas consumed by the dust control device 10 to be efficiently reduced. For example, in tunnel construction using the NATM method, a compressor is used to generate compressed air for spraying concrete. The gas supplied to the dust control device 10 may be supplied from this compressor. However, since the compressor's main purpose is to spray concrete, an amount of gas that would interfere with this spraying work cannot be consumed for dust control measures for the observation device 5. On the other hand, according to this embodiment, excessive consumption for dust control measures can be reduced. In other words, dust control measures for the observation device 5 can be carried out without interfering with the main work, such as spraying work.

[0045] The dust prevention device 10 may further include a eaves portion 24 indicated by a dotted line in Fig. 1. The eaves portion 24 is provided on the side of the panel 11 where the second nozzle 13 is located, and extends forward by a predetermined length. For example, the eaves portion 24 is attached to the front surface of the second member 18. Attaching the eaves portion 24 can help block flying debris from above.

[0046] Fig. 5 is a cross-sectional view of an example in which the dust prevention device 10 according to this embodiment is applied. The dust prevention device 10 shown in Fig. 5 includes a ring unit 30 that is attached to the observation device 5, and a lid unit 50 that covers the ring unit 30 from the front. The ring unit 30 includes an outer ring 31 and an inner ring 32 that is positioned radially inward of the outer ring 31. The outer ring 31 and the inner ring 32 are connected to each other via connecting units 33 that are spaced apart in the circumferential direction CD, and a gap 19 is formed between them.

[0047] The outer ring 31 corresponds to the first member 17 described above and includes a first nozzle 12. The first nozzle 12 of this example has an opening 12a consisting of a single slit, as shown in FIG. 4(a). The first nozzle 12 is configured with an annular groove 34 that opens forward and an annular plate 35 that covers the groove 34 from the front. The groove 34 has an inner circumferential surface 34b located radially inward relative to the space 34a and an inner circumferential surface 34c located radially outward relative to the space 34a. The width of the plate 35 in the radial direction RD is slightly narrower than the width of the groove 34 in the same direction, and the inner edge 35a of the plate 35 is in contact with the inner circumferential surface 34b. Therefore, a single slit 36 is formed as the opening 12a between the outer edge 35b of the plate 35 and the inner circumferential surface 34c of the groove 34. Furthermore, a space 34a behind the plate portion 35 in the groove portion 34 functions as a reservoir for the gas supplied from the gas supply device 16. As illustrated in FIG. 4, the shape of the opening 12a is not limited to the shape shown in FIG.

[0048] The inner ring 32 has a large diameter portion 37 and a small diameter portion 38 located in front of the large diameter portion 37. The outer diameter of the large diameter portion 37 is smaller than the inner diameter of the outer ring 31 and larger than the outer diameter of the small diameter portion 38. A mounting hole 39 for the observation device 5 is formed in the large diameter portion 37. Meanwhile, a through hole 40 communicating with the mounting hole 39 is formed in the small diameter portion 38. A step 41 onto which the panel 11 is attached is formed on the inner circumferential surface of the through hole 40.

[0049] The lid portion 50 is fixed to the inner ring 32 so as to cover the small diameter portion 38. The above-mentioned window portion 23 is formed in the lid portion 50. Furthermore, the inner circumferential surface 23a of the window portion 23 is formed with the opening 13a of the second nozzle 13 and an inclined surface 23b.

[0050] The lid portion 50 has a recess 51 that covers the small diameter portion 38. The inner diameter of the recess 51 is larger than the outer diameter of the small diameter portion 38. Therefore, when the lid portion 50 is fixed to the inner ring 32, a gap 52 is formed between the outer peripheral surface 38a of the small diameter portion 38 and the inner peripheral surface 51a of the recess 51. The gap 52 communicates with the second nozzle 13 and functions as a reservoir for the gas supplied from the gas supply device 16.

[0051] The outer dimensions of the window portion 23 are set slightly smaller than the outer dimensions of the panel 11. Therefore, the bottom surface 51b of the recess 51 contacts the edge portion 11b of the panel 11. In this example, a groove portion 51c is provided in the upper portion of the bottom surface 51b that contacts the edge portion 11b. The groove portion 51c communicates with the gap 52 and opens to a portion of the inner circumferential surface of the window portion 23. This forms the second nozzle 13. In other words, the structure combining the small-diameter portion 38 and the lid portion 50 corresponds to the second member 18 described above. Furthermore, the opening 13a in this example is formed by a portion (upper portion) of the panel 11 and the inner surface of the groove portion 51c. Therefore, the airflow 21 (see FIG. 2) can flow downward while contacting the front surface 11a of the panel 11, effectively suppressing the adhesion of flying debris. [Explanation of symbols]

[0052] DESCRIPTION OF SYMBOLS 5...observation device, 6...optical system, 10...dustproof device, 11...panel, 12...first nozzle, 12a...opening, 13...second nozzle, 13a...opening, 16...gas supply device, 17...first member, 18...second member, 19...gap, 20...air flow, 21...air flow, 22...area, 23...window portion, 23a...inner peripheral surface, 23b...inclined surface, 24...eaves portion, 30...ring portion, 31...outer ring, 32...inner ring, 33...connecting portion, 34...groove portion, 35...plate portion, 36...slit, 37...large diameter portion, 38...small diameter portion, 39...mounting hole, 40...through hole, 41...step, 50...lid portion, 51...recess

Claims

1. A dustproof device for an observation device, a light-transmitting panel provided in front of the observation device; a first nozzle that forms an airflow that flows forward while surrounding the panel; a second nozzle that forms a laminar airflow along the front surface of the panel; Dustproof device for observation equipment.

2. The opening of the first nozzle extends so as to surround the panel when viewed from the front and opens forward. The opening of the second nozzle is located on one side of the front surface of the panel when viewed from the front, and opens from one side to the other side of the front surface. A dustproof device for an observation device according to claim 1.

3. The opening of the first nozzle is located rearward of the panel. A dustproof device for an observation device according to claim 2.

4. When viewed from the front, a gap is formed between the second nozzle and the panel. A dustproof device for an observation device according to claim 3.

5. When viewed from the front, the first nozzle is located outside the area located downstream of the second nozzle. A dustproof device for an observation device according to claim 1.

6. Further, a window portion is provided in front of the panel, The second nozzle opens to a part of the inner circumferential surface that forms the window portion. A dustproof device for an observation device according to claim 1.

7. the window portion includes an inclined surface located on the inner circumferential surface at a position facing the second nozzle with the panel interposed therebetween, The inclined surface extends so as to be positioned forward as it moves away from the second nozzle. A dustproof device for an observation device according to claim 6.

8. the panel further includes a canopy portion that is provided on the side where the second nozzle is located and that extends forward. A dustproof device for an observation device according to claim 1.

Images