Dust removal 3D screen

Abstract

To secure water permeability at a higher level while appropriately capturing a contaminant in flowing water.SOLUTION: A three-dimensional screen S1 includes: a screen body part 2 having a plurality of first water passages 3A penetrating in a thickness direction; and projection water pipe parts 4 which project toward the upstream side at positions adjacent to the first water passages 3A of an upstream side face U2 of the screen body part 2, and have second water passages 3B penetrating in the thickness direction. Out of the first water passages 3A and the second water passages 3B, at least the second water passages 3B are formed so that passage cross-sectional areas on the downstream side are relatively larger than passage cross-sectional areas on the upstream side.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a three-dimensional screen for dust removal used in a dust removal device that separates impurities (screen residue, garbage) from flowing water such as discharged water from rivers and reservoirs and inflow water in sewerage facilities. [Background technology]

[0002] A dust collector is known that uses an endless porous screen to capture impurities in flowing water and then rotates the porous screen to remove them. Conventionally, the porous screen used in this type of dust collector has mainly been a flat screen, such as a wire mesh, with a flat filtering surface (capture surface) for impurities.

[0003] However, flat screens have the problem that vinyl sheets or plastic plates tend to stick to the filtration surface, impairing water permeability in a short period of time. To address this problem, the applicant of the present application has developed and proposed a three-dimensional screen as a porous screen that solves this problem. This screen has protruding water pipes that protrude upstream from the filtration surface, creating a height difference between adjacent protruding water pipes (Patent Document 1). With this three-dimensional screen, even if vinyl sheets or the like stick to the filtration surface, they straddle the protruding water pipes (a bridging phenomenon), preventing the water passage (water passage holes) from being completely blocked. As a result, water permeability is more easily maintained. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4444913 Summary of the Invention [Problem to be solved by the invention]

[0005] Although the 3D screen of Patent Document 1 has the advantage of making the water passage less likely to become clogged, as mentioned above, the overall length of the water passage is increased by the extension dimension of the protruding water pipe, and it is thought that water passage may be hindered by dirt adhering to the inner wall surface of the passage or clogging of the passage with impurities. Therefore, there is room for further improvement in terms of maintaining water passage over the long term.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a dust-removing three-dimensional screen that can properly capture impurities in flowing water while ensuring a higher degree of water permeability. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, a three-dimensional dust-removing screen according to one aspect of the present invention is a three-dimensional dust-removing screen that captures impurities in flowing water while allowing flowing water to pass through in a thickness direction, and includes a screen main body portion having a plurality of first water passages each penetrating in the thickness direction, and protruding water passage pipe portions each protruding toward the upstream side at a position adjacent to the first water passages on the upstream side of the screen main body portion and having second water passages penetrating in the thickness direction, and of the first water passages and the second water passages, at least the second water passages are formed so that the passage cross-sectional area on the downstream side is relatively larger than the passage cross-sectional area on the upstream side. The protruding water pipe portion is formed in a truncated cone shape, with the outer diameter from the middle part to the base part gradually increasing from the upstream side to the downstream side. It is characterized by the fact that

[0008] In this dust-removing three-dimensional screen, the second water passage of the protruding water passage pipe section is formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. This reduces pressure loss of the flowing water compared to when the cross-sectional area of ​​the water passage is constant over its entire length. Furthermore, the passage is less likely to become clogged with impurities. Therefore, this dust-removing three-dimensional screen can ensure a higher level of water permeability.

[0009] In the configuration of this dust-removing three-dimensional screen, when the first water passage and the second water passage that are formed so that the cross-sectional area of ​​the downstream side is relatively larger than the cross-sectional area of ​​the upstream side are defined as enlarged water passages, the enlarged water passage may be configured to include a tapered section in which the cross-sectional area of ​​the passage gradually increases from the upstream side to the downstream side.

[0010] This configuration allows the enlarged water passage to be provided with a relatively simple structure including the tapered portion. Furthermore, if the dust-removing three-dimensional screen is a resin molded product, the tapered portion can be used as the draft angle of the mold, achieving a rational configuration that combines functionality and productivity.

[0011] In this case, the tapered portion may be provided so that the passage cross-sectional area is maximized at the downstream end of the expanded water passage.

[0012] With this configuration, impurities that have entered the enlarged water passage can easily escape downstream, making it less likely for impurities to clog the passage.

[0013] In the above-described configuration of the dust-removing three-dimensional screen, the entire enlarged water passage may be the tapered portion. With this configuration, the entire enlarged water passage is the tapered portion, so that pressure loss of the flowing water can be effectively suppressed.

[0014] In the above-described three-dimensional dust removing screen, the portion of the enlarged water passage other than the tapered portion may be a straight portion having a constant cross-sectional area.

[0015] According to this configuration, it is possible to provide a tapered portion in the enlarged water passage within the range allowed based on the specific structure, such as the arrangement of the first and second water passages.

[0016] Furthermore, the above-mentioned dust-removing three-dimensional screen may include a plurality of types of protruding water-passing pipe sections that are different from one another in the length of protrusion from the upstream side surface of the screen main body.

[0017] According to this configuration, since multiple types of protruding water pipe sections with different protruding dimensions are provided, the second water passage is less likely to become blocked even if a vinyl sheet or plastic plate is caught across the protruding water pipe sections.

[0018] In the above-described three-dimensional dust removal screen, the distal end periphery of the protruding water passage pipe portion may be formed to have an arc-shaped cross section.

[0019] According to this configuration, impurities adhering to the tip of the protruding water pipe portion can be easily peeled off, and therefore the tip is less likely to be clogged with impurities. In the above-mentioned three-dimensional dust-removing screen, the portion of the enlarged water passage including the front downstream end may be a straight portion having a constant passage cross-sectional area. [Effects of the Invention]

[0020] As described above, the dust-removing three-dimensional screen of the present invention can adequately capture impurities in flowing water while ensuring a high degree of water permeability. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view of a dust removal device equipped with a dust removal three-dimensional screen according to the present invention. [Figure 2] 2 is a schematic plan cross-sectional view of the dust removal device. [Figure 3] FIG. 2 is a plan view of a main part of the dust removing three-dimensional screen (first embodiment). [Figure 4] 4 is a cross-sectional view of the dust-removing three-dimensional screen (a cross-sectional view taken along line IV-IV in FIG. 3). [Figure 5] FIG. 10 is a cross-sectional view of a main part of a dust-removing three-dimensional screen according to a modified example. [Figure 6] FIG. 10 is a cross-sectional view of a dust-removing three-dimensional screen according to a second embodiment. [Figure 7] FIG. 10 is a cross-sectional view of a main part of a dust-removing three-dimensional screen according to a modified example. [Figure 8] FIG. 10 is a cross-sectional view of a dust-removing three-dimensional screen according to a third embodiment. [Figure 9]FIG. 10 is a cross-sectional view of a main part of a dust-removing three-dimensional screen according to a modified example. [Figure 10] FIG. 10 is a cross-sectional view of a dust-removing three-dimensional screen according to a fourth embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a main part of a dust-removing three-dimensional screen according to a modified example. [Figure 12] FIG. 10 is a cross-sectional view of a dust-removing three-dimensional screen according to a fifth embodiment. [Figure 13] FIG. 10 is a cross-sectional view of a main part of a dust-removing three-dimensional screen according to a modified example. [Figure 14] FIG. 10 is a cross-sectional view of a tip portion of a protruding water pipe portion according to a modified example. [Figure 15] FIG. 2 is a schematic diagram showing a straight water passage and a tapered water passage. DETAILED DESCRIPTION OF THE INVENTION

[0022] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] [Dust removal equipment configuration] Fig. 1 is a perspective view showing a dust removal device 10 to which a dust removal three-dimensional screen S1 according to the present invention (hereinafter abbreviated as three-dimensional screen S1) is applied, and Fig. 2 is a schematic plan view of the dust removal device 10. Fig. 3 is a plan view of the main part of the three-dimensional screen S1 (a plan view of the dust removal screen 1 as seen from the inner peripheral side). Fig. 1 shows the dust removal device 10 with a part broken away.

[0024] 1 and 2, a dust removal device 10 includes a dust removal screen 1 for capturing impurities in flowing water through a water channel 11, a drive mechanism for driving the dust removal screen 1, and a removal device 14 for dropping and collecting the captured impurities from the dust removal screen 1. A three-dimensional screen S1 according to the present invention is incorporated into the dust removal screen 1.

[0025] The dust removal screen 1 is formed in the shape of an endless belt so as to penetrate the waterway 11 in the longitudinal direction. The dust removal screen 1 is provided vertically between a partition wall 12 protruding into the waterway 11 and an intermediate support wall 13 erected in the center of the waterway 11 downstream of the partition wall 12, with its upper portion exposed above the water surface, and is configured to rotate when the drive mechanism is operated.

[0026] More specifically, guides 20 for guiding the dust removal screen 1 are disposed on the partition walls 12 and the intermediate support walls 13, and a rotor 22 having a pair of sprockets 23 is supported above these guides 20. The dust removal screen 1 is stretched across these rotors 22 and guides 20, and a chain 30 (described later) of the dust removal screen 1 meshes with each of the sprockets 23. A motor 25 is disposed beside the rotor 22, and a drive chain 28 is stretched between a sprocket 26 attached to the output shaft of the motor 25 and a sprocket 27 attached to the rotating shaft of the rotor 22. In other words, when the rotor 22 is rotationally driven by the motor 25, the dust removal screen 1 rotates and moves in accordance with the rotation of the rotor 22.

[0027] As shown in Figure 3, the dust removal screen 1 comprises a pair of parallel endless chains 30 (only one side is shown in the figure), a plurality of frames 34 connected to both chains 30 and aligned in a circumferential direction between the chains 30, and a three-dimensional screen S1 detachably attached to each frame 34 with bolts and nuts. In the dust removal screen 1, adjacent frames 34 in the circumferential direction are connected to each other via connecting members (not shown), made of rubber, for example. With this configuration, the frames 34 are connected endlessly without any gaps while maintaining flexibility.

[0028] As shown in FIG. 1, the removal device 14 has a spray device 40 disposed directly above the rotor 22 and a trough 42 disposed inside the dust removal screen 1 opposite the spray device 40.

[0029] The spray device 40 is configured to pump up flowing water using, for example, a pump installed at the bottom of the waterway and spray water at high pressure toward the dust removal screen 1, causing the trapped impurities to fall off under the water pressure. The trough 42 is located below the dust removal screen 1, sandwiching the spray device 40 between them, and is configured to capture the impurities that fall off the dust removal screen 1 under the water pressure and guide them to a collection box 44.

[0030] In the dust removal device 10 as described above, the flowing water in the water channel 11 is guided to the inside of the dust removal screen through the opening 12a of the partition wall 12 as shown by the outline arrows in Figures 1 and 2, and flows downstream along the circumferential surface of the dust removal screen 1. Therefore, as the flowing water passes through the inner circumferential surface of the dust removal screen 1, impurities in the flowing water are captured.

[0031] While the impurities are being captured in this manner, the dust removal screen 1 is rotated by the driving force of the motor 25. As the dust removal screen 1 rotates, the captured impurities are pulled up from the water and carried to the upper end of the screen (the position of the rotor 22). Then, high-pressure water is sprayed by the spray device 40, removing the impurities from the dust removal screen 1 and collecting them in the trough 42. The water flow from the spray device 40 guides the collected impurities along the trough 42 to a collection box 44, from which they are carried out of the waterway by an operator.

[0032] [Structure of the 3D screen S1 (first embodiment)] Next, a detailed structure of the three-dimensional screen S1 that is applied to the dust removal screen 1 will be described. Fig. 4 is a cross-sectional view of the three-dimensional screen S1 (a cross-sectional view taken along line IV-IV in Fig. 3).

[0033] As shown in Figures 3 and 4, the three-dimensional screen S1 is roughly flat and rectangular in shape when viewed from above, and as described above, is attached to the frame 34 of the dust removal screen 1, and captures impurities in the flowing water while allowing the flowing water to pass through it in the thickness direction.

[0034] The three-dimensional screen S1 comprises a screen main body 2 having a plurality of first water passages 3A each penetrating the screen in its thickness direction, and protruding water passage pipes 4 each protruding upstream from a position adjacent to the first water passages 3A on the upstream side U2 of the screen main body 2 and having second water passages 3B penetrating the three-dimensional screen S1 in its thickness direction. The screen main body 2 and the protruding water passage pipes 4 are integrally formed from the same synthetic resin material (e.g., polypropylene). The terms "upstream" and "downstream" refer to the flow direction of water passing through the three-dimensional screen S1. The three-dimensional screen S1 is assembled to the frame 34 so that the protruding water passage pipes 4 are located on the inner periphery of the dust-removing screen 1.

[0035] The first water passage 3A is a water passage with a circular cross section. The protruding water passage pipe section 4 is cylindrical, and therefore the second water passage 3B also has a circular cross section. As shown in Figures 3 and 4, the upstream side surface U2 of the screen main body 2 is provided with multiple rows of holes in the vertical direction, in which the first water passages 3A and the protruding water passage pipe sections 4 (second water passages 3B) are arranged alternately in a horizontal direction. In vertically adjacent hole rows, the first water passages 3A and the protruding water passage pipe sections 4 are arranged in reverse so that the first water passages 3A are not vertically adjacent to each other.

[0036] As shown in Figure 4, the first water passage 3A and the second water passage 3B are both formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. Specifically, the first water passage 3A and the second water passage 3B are both formed in a tapered shape (corresponding to the "tapered section" of the present invention) in which the cross-sectional area gradually increases from the upstream end to the downstream end. That is, the first water passage 3A is formed so that the inner diameter D1a is smallest at the upstream end and the inner diameter D1b is largest at the downstream end. The second water passage 3B is formed so that the inner diameter D2a is smallest at the upstream end and the inner diameter D2b is largest at the downstream end. The inner diameter D1a at the upstream end of the first water passage 3A is equal to the inner diameter D2a at the upstream end of the second water passage 3B.

[0037] As described above, the first water passage 3A and the second water passage 3B are formed so that the cross-sectional area of ​​the downstream passage is relatively larger than the cross-sectional area of ​​the upstream passage. Therefore, in this example, both the first water passage 3A and the second water passage 3B correspond to the "enlarged water passage" of the present invention.

[0038] [Action and effect] According to the structure of the three-dimensional screen S1 described above, the upstream side surface U2 of the screen main body 2 has a three-dimensional structure with the protruding water pipe section 4, so that the captured impurities cause a bridge phenomenon due to the unevenness of the protruding water pipe section 4, and flow through the gaps into the first water passage 3A. Therefore, as with the conventional three-dimensional screen (Patent Document 1), impurities are prevented from sticking to the upstream side surface U2 and blocking the water passage.

[0039] Furthermore, the water passage of the protruding water pipe section 4 (second water passage 3B) is tapered so that the cross-sectional area gradually increases from the upstream end to the downstream end (hereinafter, sometimes referred to as a "tapered water passage"). This reduces the pressure loss of flowing water compared to when the cross-sectional area is constant over the entire length of the protruding water pipe section (hereinafter, sometimes referred to as a "straight water passage"). Therefore, even though the protruding water pipe section 4 protrudes upstream from the screen main body 2, it is less susceptible to the effects of dirt adhering to the inner wall surface of the water passage. In addition, even if impurities flow into the second water passage 3B, the cross-sectional area gradually increases from the upstream end to the downstream end, making it less likely for the impurities to clog the water passage.

[0040] Furthermore, because the first water passage 3A and the second water passage 3B of the three-dimensional screen S1 are tapered passages, pressure loss is unlikely to occur, just like the second water passage 3B, and impurities that flow in are unlikely to clog the passages. Therefore, this three-dimensional screen S1 can ensure high water permeability while properly capturing impurities in the flowing water.

[0041] Here, we will compare the water permeability of a straight water channel and a tapered water channel, as shown in Figure 15, based on head loss, which is a physical quantity that represents the pressure loss that occurs in the water flow of a water channel as head pressure.

[0042] If the inner diameter of a straight passage is a, the friction resistance coefficient of the passage is λ, the flow velocity in the passage is V, the passage length is L, and the ratio of the passage length to the inlet diameter is γ (= L / a), the head loss hf0 of the straight passage is given by the following equation.

[0043] hf0=k0V 2 =[(3 / 2)+λγ]V 2 ...(Formula 1) Also, as shown in Figure 15, consider a tapered waterway where the inner diameter of the straight passage is the same as the inlet diameter. If the ratio of the outlet diameter b to the inlet diameter a of the tapered waterway is k (= b / a), the head loss of the tapered waterway is hf a is expressed by the following equation:

[0044] hf a =k a V 2 =[(1 / 2)+λγ[2 / (1+k)] 5 +(1 / k 4 )]V 2 ...(Formula 2) Using Equations 1 and 2, the head loss ratio n of a tapered channel to a straight channel can be calculated as follows:

[0045] n=hf a / hf0=[(1 / 2)+λγ[2 / (1+k)] 5 +(1 / k 4 )] / [(3 / 2)+λγ] (Eq. 3) Here, if the straight passage's inner diameter a = 5 mm and passage length L = 25 mm, and the tapered passage's inlet diameter a = 5 mm, outlet diameter b = 5.5 mm, and passage length L = 25 mm, then γ = 5 and k = 1.1. Furthermore, since the 3D screen S1 is made of resin, corrosion surcharges are not taken into account. If the flow velocity V in the passage is 0.5 m / s to 1.0 m / s, the passage's friction resistance coefficient λ is calculated as λ = 0.0278 to 0.03, based on a well-known formula for steel pipes. Substituting these values ​​into Equation 3, the head loss ratio n of the tapered passage to the straight passage is n = 1.3 / 1.65 = 0.788.

[0046] In other words, tapered water passages can reduce pressure loss to approximately 80% of that of straight water passages. In other words, tapered water passages reduce pressure loss by 20% compared to straight water passages. Therefore, the above-mentioned three-dimensional screen S1, in which the second water passage 3B and the first water passage 3A of the protruding water passage pipe section 4 are tapered water passages, can be said to ensure a higher level of water permeability. Note that the above results are for tapered water passages, but it can be inferred that a similar pressure loss reduction effect can be achieved if the water passage is formed so that the cross-sectional area of ​​the downstream passage is relatively larger than the cross-sectional area of ​​the upstream passage.

[0047] Furthermore, when the three-dimensional screen S1 is cleaned by the spray device 40, high-pressure water is sprayed onto the downstream side surface D2 of the three-dimensional screen S1, so that the first water passage 3A and the second water passage 3B can be cleaned efficiently. D1b, D2b Since the taper-shaped water passage has a maximum diameter ( D1b, D2b ) into the water passage, the high-pressure water acts more effectively on the inner wall surface of the water passage. Therefore, compared to the case of a straight water passage, it is possible to clean the first water passage 3A and the second water passage 3B more efficiently. This contributes to suppressing the adhesion of dirt to the inner wall surface of the water passage and thus reducing the pressure loss of the flowing water, and is also advantageous in ensuring the water permeability of the three-dimensional screen S1.

[0048] Furthermore, as mentioned above, the three-dimensional screen S1 is a resin molded product made of synthetic resin material, but because both the first water passage 3A and the second water passage 3B are tapered, the tapered shape can be used as the draft angle of the molding die. Therefore, it can be said that this three-dimensional screen S1 achieves a rational configuration that combines functionality and productivity.

[0049] 3 and 4, the protruding dimension h of each protruding water pipe section 4, i.e., the dimension from the upstream side surface U2 of the screen main body 2 to the tip of the protruding water pipe section 4, is the same. However, as shown in Fig. 5, the three-dimensional screen S1 may be configured to include multiple types of protruding water pipe sections 4 with different protruding dimensions.

[0050] Fig. 5 is a cross-sectional view of a main part of a three-dimensional screen S1 according to a modified example, corresponding to Fig. 4. The three-dimensional screen S1 shown in Fig. 5 is provided with a first protruding water pipe section 4H with a protruding dimension h1 and a second protruding water pipe section 4L with a smaller protruding dimension h2 as the protruding water pipe section 4. The protruding dimension h2 of the second protruding water pipe section 4L is, for example, approximately half the protruding dimension h1 of the first protruding water pipe section 4H.

[0051] In the three-dimensional screen S1 shown in Fig. 5, the first water passage 3A, first protruding water pipe section 4H (second water passage 3B), and second protruding water pipe section 4L (second water passage 3B) are arranged in a row in the horizontal direction, and the hole rows are arranged so that the first protruding water pipe section 4H and the second protruding water pipe section 4L are arranged alternately on either side of the first water passage 3A. In vertically adjacent rows, the arrangement of the first water passages 3A, first protruding water pipe section 4H, and second protruding water pipe section 4L in each hole row is regularly shifted so that the first water passages 3A are not vertically adjacent to each other.

[0052] With the three-dimensional screen S1 shown in Fig. 5, even if the captured impurities bridge across the first protruding water pipe section 4H, the flowing water will pass through the gap and enter the second water passage 3B and the first water passage 3A of the second protruding water pipe section 4L, thereby preventing the water passages 3A and 3B from being blocked by the impurities. Therefore, with the three-dimensional screen S1 of Fig. 5, it is possible to ensure a high degree of water permeability while enjoying the same effects as the three-dimensional screen S1 of Fig. 4 described above.

[0053] [Second embodiment of the 3D screen] Fig. 6 is a cross-sectional view of a main part of a three-dimensional screen S2 according to the second embodiment, corresponding to Fig. 4 described above. The basic structure of the three-dimensional screen S2 of the second embodiment is the same as that of the three-dimensional screen S2 of the first embodiment, and the following explanation will mainly focus on the differences from the three-dimensional screen S1 of the first embodiment. This also applies to the three-dimensional screens S3 to S5 of the third to fifth embodiments described later.

[0054] In the three-dimensional screen S2 of the second embodiment, the shapes of the first water passage 3A and the second water passage 3B are different from those of the three-dimensional screen S1 of the first embodiment.

[0055] Specifically, the second water passage 3B includes a straight section 5a, which is a section with a constant inner diameter, and a tapered section 5b, which is a section where the inner diameter gradually increases from the upstream side to the downstream side. Roughly speaking, the section within the protruding water passage pipe section 4 is the straight section 5a, and the section downstream of that is the tapered section 5b. The first water passage 3A also includes a similar straight section 6a and tapered section 6b. Within the first water passage 3A, the section near the inlet for flowing water is the straight section 6a, and the section downstream of that is the tapered section 6b.

[0056] In the three-dimensional screen S2 of the second embodiment, the second water passage 3B is also formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. Therefore, the pressure loss of the flowing water is reduced compared to when the entire second water passage 3B is a straight water passage, and the flowing impurities are less likely to clog the passage. Similarly, the first water passage 3A includes a tapered portion 6b and is formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. Therefore, the pressure loss of the flowing water is reduced compared to when the entire first water passage 3A is a straight water passage, and the flowing impurities are less likely to clog the passage.

[0057] Therefore, the three-dimensional screen S2 of the second embodiment can also provide the same effects as the three-dimensional screen S1 of the first embodiment.

[0058] Note that the three-dimensional screen S2 of the second embodiment may also be configured to include a first protruding water pipe section 4H and a second protruding water pipe section 4L having different protruding dimensions as the protruding water pipe section 4, as shown in Fig. 7. This configuration makes it possible to ensure a higher degree of water permeability for the same reasons as in the case of the three-dimensional screen S1 (see Fig. 5) according to the modified example of the first embodiment.

[0059] [Third embodiment of the 3D screen] Figure 8 is a cross-sectional view of a main part of a three-dimensional screen S3 according to the third embodiment, and corresponds to the cross-sectional view of Figure 4. The three-dimensional screen S3 of the third embodiment is similar to the three-dimensional screen S2 of the second embodiment in that the water passage includes a straight portion and a tapered portion.

[0060] In the three-dimensional screen S3 of the third embodiment, the second water passage 3B has a section within the protruding water passage pipe section 4 that is a straight section 5a, a section downstream of which is a tapered section 5b that expands in diameter, and a section downstream of the tapered section 5b that is a straight section 5c.

[0061] Similarly, the first water passage 3A also includes straight sections 6a, 6c and a tapered section 6b. In the first water passage 3A, the section near the inlet for flowing water is the straight section 6a, a section downstream of that is the tapered section 6b with an increased diameter, and the section downstream of the tapered section 6b is the straight section 6c.

[0062] In the three-dimensional screen S3 of the third embodiment, the second water passage 3B is also formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. Therefore, compared to when the entire second water passage 3B is a single straight water passage, pressure loss of the flowing water is reduced and inflowing impurities are less likely to clog the passage. Similarly, the first water passage 3A is also formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. Therefore, compared to when the entire first water passage 3A is a single straight water passage, pressure loss of the flowing water is reduced and inflowing impurities are less likely to clog the passage.

[0063] Therefore, the three-dimensional screen S3 of the third embodiment can also provide the same effects as the three-dimensional screen S1 of the first embodiment.

[0064] Note that the three-dimensional screen S3 of the third embodiment may also be configured to include a first protruding water pipe section 4H and a second protruding water pipe section 4L with different protruding dimensions as the protruding water pipe section 4, as shown in Fig. 9. This configuration makes it possible to ensure a higher degree of water permeability for the same reasons as the three-dimensional screen S1 (see Fig. 5) according to the modified example of the first embodiment.

[0065] [Fourth embodiment of the 3D screen] Fig. 10 is a cross-sectional view of a main part of a three-dimensional screen S4 according to the fourth embodiment, and corresponds to Fig. 4. The three-dimensional screen S4 of the fourth embodiment is generally the same as the three-dimensional screen S3 of the third embodiment, but differs in structure from the three-dimensional screen S3 of the third embodiment in the following points.

[0066] In the fourth embodiment, the section of tapered portion 5b provided between straight portions 5a and 5c of second water passage 3B is longer than tapered portion 5b of the third embodiment. Specifically, the section of tapered portion 5b is approximately half the thickness of the screen main body. The same is true for tapered portion 6b of first water passage 3A, where the section of tapered portion 6b is approximately half the thickness of the screen main body.

[0067] Furthermore, the protruding water pipe section 4 of the fourth embodiment is formed in a truncated cone shape that gradually increases in diameter from the middle to the base end (from the upstream side to the downstream side) from the tip end to the base end. In other words, the protruding water pipe section 4 is provided, from the middle to the base end, with an enlarged diameter section 4a whose outer diameter gradually increases from the tip end to the base end.

[0068] In the three-dimensional screen S4 of the fourth embodiment, the second water passage 3B is also formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. Therefore, compared to when the entire second water passage 3B is a single straight water passage, pressure loss of the flowing water is reduced and inflowing impurities are less likely to clog the passage. Similarly, the first water passage 3A is also formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. Therefore, compared to when the entire first water passage 3A is a single straight water passage, pressure loss of the flowing water is reduced and inflowing impurities are less likely to clog the passage.

[0069] Therefore, the three-dimensional screen S4 of the fourth embodiment can also achieve the same effects as the three-dimensional screen S1 of the first embodiment. Furthermore, in this three-dimensional screen S4, the expanded diameter portion 4a is provided from the middle to the base of the protruding water pipe portion 4, thereby reducing the flat area around the inlet of the first water passage 3A. This has the advantage of preventing fine impurities from accumulating on the flat area.

[0070] 11, the three-dimensional screen S4 of the fourth embodiment may also be configured to include a first protruding water pipe section 4H and a second protruding water pipe section 4L having different protruding dimensions as the protruding water pipe section 4. This configuration makes it possible to ensure a higher degree of water permeability for the same reasons as the three-dimensional screen S1 (see FIG. 5) according to the modified example of the first embodiment.

[0071] [Fifth embodiment of the 3D screen] FIG. 12 is a cross-sectional view of a main part of a three-dimensional screen S5 according to the fifth embodiment, and corresponds to the cross-sectional view of FIG. 4 described above.

[0072] In the three-dimensional screen S3 of the fifth embodiment, the section of the second water passage 3B within the protruding water passage pipe section 4 is a straight section 5a, and the section within the screen main body section 2 is a straight section 5c with a larger inner diameter than the straight section 5a. There is no tapered section, and the straight sections 5a and 5c are directly connected. In the first water passage 3A as well, the section near the flowing water inlet is a straight section 6a, and the section downstream of that is a straight section 6c with a larger inner diameter than the straight section 6a.

[0073] In the three-dimensional screen S5 of the fifth embodiment, the second water passage 3B is also formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. Therefore, compared to when the entire second water passage 3B is a single straight water passage, pressure loss of the flowing water is reduced and inflowing impurities are less likely to clog the passage. Similarly, the first water passage 3A is also formed so that the cross-sectional area on the downstream side is relatively larger than the cross-sectional area on the upstream side. Therefore, compared to when the entire first water passage 3A is a single straight water passage, pressure loss of the flowing water is reduced and inflowing impurities are less likely to clog the passage.

[0074] Therefore, the three-dimensional screen S5 of the fifth embodiment can also provide the same effects as the three-dimensional screen S1 of the first embodiment.

[0075] 13, the three-dimensional screen S5 of the fifth embodiment may also be configured to include a first protruding water pipe section 4H and a second protruding water pipe section 4L having different protruding dimensions as the protruding water pipe section 4. This configuration makes it possible to ensure a higher degree of water permeability for the same reasons as the three-dimensional screen S1 (see FIG. 5) according to the modified example of the first embodiment.

[0076] The above describes the three-dimensional screens S1 to S5 of the present invention, but the three-dimensional screens S1 to S5 described above are merely examples of preferred embodiments of the present invention, and their specific configurations can be modified as appropriate without departing from the spirit of the present invention.

[0077] In the three-dimensional screens S1 to S5 of the embodiments, the screen main body 2 and the protruding water pipes 4 are integrally molded from a synthetic resin material, but either or both of the screen main body 2 and the protruding water pipes 4 (4H, 4L) may be made of metal. In this case, the screen main body 2 and the protruding water pipes 4 (4H, 4L) may be fixed to each other by joining means such as screws or welding.

[0078] In the three-dimensional screens S1 to S5 of the embodiment, the first water passage 3A and the second water passage 3B are both circular in cross section, but they may also be polygonal in cross section (square, rectangle, regular hexagon, etc.). The same applies to the (outline of) the protruding water passage pipe portion 4.

[0079] In the modified examples of the three-dimensional screens S1 to S5 of the embodiment (Figures 5, 7, 9, 11, and 13), two types of protruding water pipe sections 4H and 4L with different protruding dimensions are provided as the protruding water pipe sections 4, but three or more types of protruding water pipe sections 4 with different protruding dimensions may also be provided.

[0080] Furthermore, in the three-dimensional screens S1 to S5 of the embodiment, the tips of the protruding water pipes 4 (4H, 4L) are flat, but the periphery of the tips of the protruding water pipes 4 (4H, 4L) may be formed with an arc-shaped cross section, as shown in Fig. 14. This configuration has the advantage that impurities adhering to the tips of the protruding water pipes 4 can be easily peeled off, making the tips less likely to be clogged with impurities. [Explanation of symbols]

[0081] 1 Dust removal screen 2 Screen body 3A 1st waterway 3B 2nd waterway 4. Protruding water pipe section 4H First protruding water pipe section 4L Second protruding water pipe section 5a, 5c straight section 5b Tapered section 6a, 6c straight section 6b Tapered section S1, S2, S3, S4, S5 3D screens (dust removal 3D screens)

Claims

1. A three-dimensional dust-removing screen that captures impurities in flowing water while allowing flowing water to pass through in the thickness direction, a screen main body portion having a plurality of first water passages each penetrating in the thickness direction; The screen body comprises a protruding water pipe section that protrudes toward the upstream side at a position adjacent to the first water channel on the upstream side of the screen body and has a second water channel that penetrates in the thickness direction, Of the first and second water channels, at least the second water channel is formed such that the cross-sectional area of ​​the downstream channel is relatively larger than the cross-sectional area of ​​the upstream channel. The aforementioned protruding water passage section is formed in a frustum shape, where the outer diameter from the middle section to the base section gradually increases from the upstream side to the downstream side, characterized in that it is a three-dimensional screen for dust removal.

2. The dust-removing three-dimensional screen according to claim 1, When a channel is defined as an enlarged channel among the first and second channels described above, such that the cross-sectional area of ​​the downstream channel is relatively larger than the cross-sectional area of ​​the upstream channel, The three-dimensional screen for removing dust is characterized in that the enlarged water passage includes a tapered portion in which the passage cross-sectional area gradually increases from the upstream side to the downstream side.

3. 3. The dust-removing three-dimensional screen according to claim 2, The three-dimensional screen for removing dust is characterized in that the tapered portion is provided so that the passage cross-sectional area is maximized at the downstream end of the enlarged water passage.

4. The dust-removing three-dimensional screen according to claim 2 or 3, A three-dimensional screen for removing dust, characterized in that the entire enlarged water passage is the tapered portion.

5. The dust-removing three-dimensional screen according to claim 2 or 3, A three-dimensional screen for removing dust, wherein the portion of the enlarged water passage other than the tapered portion is a straight portion having a constant cross-sectional area of ​​the passage.

6. The dust-removing three-dimensional screen according to any one of claims 1 to 3, A three-dimensional dust removal screen characterized in that the aforementioned protruding water passage sections are provided with a plurality of types of protruding water passage sections, each having a different protruding dimension from the upstream side surface of the screen body.

7. The dust-removing three-dimensional screen according to any one of claims 1 to 3, The three-dimensional screen for removing dust is characterized in that the peripheral edge of the tip of the protruding water passage pipe portion is formed to have an arc-shaped cross section.

8. The dust-removing three-dimensional screen according to claim 2, A three-dimensional screen for removing dust, wherein a portion of the enlarged water passage including a front downstream end is a straight portion having a constant cross-sectional area of ​​the passage.

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