Removal device of drifting pumice stone

Abstract

To remove a huge amount of pumice stones drifting on a sea surface.SOLUTION: A removal device of a drifting pumice stone is, for example, a dustpan (intake port structure of drifting pumice stones which is composed of a depth regulation part for regulating a suction sea surface depth, an opening degree regulation part for regulating a suction sea surface opening degree, a suction opening constituted forward of the depth regulation part and the opening degree regulation part, and a pumice stone suction port arranged at the rear part of the depth regulation part and the opening degree regulation part), gives suction force to the pumice stone intake port in a part corresponding to a holder of a normal dustpan, and sucks the pumice stone.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device for efficiently recovering large amounts of drifting pumice that drifts on the sea surface due to the explosion of an underwater volcano or the like, or large amounts of drifting debris that drifts on the sea surface due to a tsunami or the like, from the surface of the water, such as the sea. [Background technology]

[0002] In 2021, a problem occurred in which large amounts of pumice, believed to have been produced by the eruption of the undersea volcano Fukutoku Okanoba in the Ogasawara Islands, drifted across the Pacific Ocean and washed up on the coasts of Okinawa and Kagoshima prefectures. As of November 2021, it is predicted that the pumice will also drift off the coast of the Kanto region, raising concerns about adverse effects such as engine trouble for fishing boats and the death of farmed fish in fish farms due to lack of oxygen. The national and prefectural governments that manage fishing ports are rushing to prepare equipment to prevent pumice from washing ashore, but no effective countermeasures have yet been found. Similar events can be expected not only from undersea volcanic eruptions, but also from a variety of other cases, such as a cargo ship running aground and its cargo being scattered over the ocean, or plastic waste being released into the sea or lakes due to flooding.

[0003] Dredging of oceans, rivers, lakes, and marshes has traditionally focused on materials that have accumulated at the bottom. Dredging also involves the collection of floating materials on the ocean surface, such as oil spilled from stranded tankers, which is relatively easy to collect because it is a liquid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-177053 [Patent Document 2] Patent Application No. 10-232719 Summary of the Invention [Problem to be solved by the invention]

[0005] The dredging technology described in Patent Document 1 can remove mud and gravel that has accumulated on the seabed, but it cannot recover pumice or plastic waste floating on the sea surface.

[0006] The spilled oil recovery technology described in Patent Document 2 differs from that described in Patent Document 1 in that it can recover floating objects on the sea surface, but it has the problem that it is limited to liquid oil and cannot be applied to floating objects on the sea such as pumice.

[0007] The present invention aims to efficiently and large-scalely remove solid waste such as pumice and plastics floating on the surface of the sea, lakes, rivers, etc.

[0008] The present invention was created in consideration of the above-mentioned problems, and aims to provide an apparatus and method for efficiently and on a large scale removing extremely large amounts of unwanted solid floating matter resulting from undersea volcanic eruptions, etc. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, as a first means, a drifting pumice etc. intake structure is provided which comprises a depth regulating section for regulating the suction water surface depth, an opening regulating section for regulating the suction water surface opening, a suction opening formed in the front by the depth regulating section and the opening regulating section, and a pumice etc. suction port located behind the depth regulating section and the opening regulating section.

[0010] As a second means, we provide a drifting pumice intake structure based on the first means, which further has a depth maintenance section for maintaining the depth control section of the drifting pumice intake structure at a predetermined position below the water surface.

[0011] Furthermore, as a third means, a drifting pumice etc. intake structure based on the first means or the second means is provided, which further has a guide section provided in front of the suction opening for guiding drifting pumice etc. to the suction opening.

[0012] Furthermore, as a fourth means, a drifting pumice etc. intake structure based on any one of the first means to the fourth means is provided, in which the depth maintenance section has an adjustment means for adjusting the depth restriction section in the vertical direction.

[0013] Furthermore, as a fifth means, there is provided a drifting pumice etc. removal device comprising a drifting pumice etc. intake structure of any one of the first to fourth means, and a forced movement device for forcibly moving the drifting pumice etc. toward the suction opening of the drifting pumice etc. intake structure.

[0014] Furthermore, as a sixth means, there is provided a drifting pumice etc. removal device comprising the drifting pumice etc. intake structure of any one of the first to fourth means, and a suction device comprising an ejector for sucking pumice etc. from the pumice etc. suction port, and a drive fluid pump for driving the ejector.

[0015] Furthermore, as a seventh means, a drifting pumice etc. removal device is provided which comprises a drifting pumice etc. intake structure of any one of the first to fourth means, and a float device for floating on the water surface, the float device having a support part for supporting the drifting pumice etc. intake structure.

[0016] As an eighth means, we provide a drifting pumice etc. removal device based on any of the fifth to seventh means, which further includes a suction device consisting of an ejector for sucking pumice etc. from a pumice etc. suction port and a drive fluid pump for driving the ejector.

[0017] Furthermore, as a ninth means, a drifting pumice etc. removal device based on any one of the fifth means to the eighth means is provided, which further has a silt fence arranged so as to guide the drifting pumice etc. toward the suction opening of the drifting pumice etc. intake structure.

[0018] As a tenth means, we provide a drifting pumice etc. removal device based on any one of the fifth to ninth means, which further has a sieving device for separating the drifting pumice etc. sucked up by the suction device from seawater etc.

[0019] Furthermore, as an eleventh means, there is provided a method for removing drifting pumice, etc., which includes a step of removing drifting pumice, etc., floating on the sea using the drifting pumice, etc. intake structure described in any one of the first means to the fourth means.

[0020] Furthermore, as an eleventh means, we provide a method for removing drifting pumice, etc. based on the eleventh means, which includes a step of lowering the upper surface of the depth-regulating part of the drifting pumice, etc. intake structure described in any one of the first to fourth means below the depth below the water surface of the pumice, etc. floating on the sea, thereby removing the floating drifting pumice, etc.

[0021] Furthermore, as a thirteenth means, there is provided a method for removing drifting pumice, etc., based on the eleventh or twelfth means, which further includes a step of arranging silt fences so that the spacing between them gradually narrows toward the suction opening of the drifting pumice, etc. intake structure described in any one of the first to fourth means.

[0022] The present invention targets removal of unwanted materials that scatter and accumulate on the water surface, but the removal targets are not limited to the water surface, and may also be on the surface of oil or other liquids. Furthermore, the removal targets are pumice and plastic waste, but are not limited to these, and various floating objects such as wood chips and aquatic plants (e.g., water hyacinth) can also be targeted. [Effects of the Invention]

[0023] According to the present invention, floating matter such as pumice that is scattered or accumulated in large quantities and floating on the sea surface or the like can be efficiently and quickly recovered. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 2 is a perspective view of the drifting pumice and other intake structure of the first embodiment. [Figure 2]This is a conceptual diagram showing the removal of drifting pumice and the like, as viewed from the side, using the drifting pumice and the like intake structure of Embodiment 1. Note that in the drawing, the depth restriction part is positioned slightly shallower than the depth of the drifting pumice, but more accurately, it is appropriate to position it at a position sufficiently deeper than the depth of the drifting pumice. [Figure 3] FIG. 1 is a perspective view showing a float for mounting a structure for maintaining the drifting pumice and other intake structure of the first embodiment at a predetermined position below the water surface. [Figure 4] FIG. 10 is a perspective view of a jet flow device, which is an example of a forcible moving device for forcibly moving drifting pumice and the like in the second embodiment. [Figure 5] 10 is a conceptual plan view of a drifting pumice and the like removal device of the second embodiment, as viewed from above. FIG. [Figure 6] This is a conceptual diagram observed from the side, showing how the depth control section of the drifting pumice and other inlet structure of the drifting pumice and other removal device of embodiment 2 is maintained at a predetermined position below the water surface by an upper and lower winding pipe, which is an example of a depth maintenance section. [Figure 7] This is a conceptual diagram showing the drifting pumice and other debris removal device of embodiment 2 observed from above, with a silt fence being placed to guide drifting pumice and other debris toward the suction opening of the drifting pumice and other debris intake structure. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the scope of the present invention is not limited to the embodiments described below, and various modifications and changes can be made to the embodiments described below without departing from the gist of the present invention.

[0026] In "Embodiment 1," we will mainly explain "Claims 1, 2, 3, and 4." In "Embodiment 2," we will mainly explain "Claims 5, 6, 7, 8, 9, and 10." In "Embodiment 3," we will mainly explain "Claims 11, 12, and 13." <Outline of Embodiment 1>

[0027] The first embodiment is a structure for taking in floating pumice etc., which is used to remove floating pumice etc. on the sea surface, and is a structure used as part of a floating pumice etc. removal device described later. <Configuration of First Embodiment>

[0028] 1 is a diagram showing the intake structure for drifting pumice, etc. of this embodiment. The intake structure for drifting pumice, etc. is composed of a depth control unit, an opening control unit, a suction opening, a pumice, etc. suction port, and, as necessary, a depth maintenance unit, a guidance unit, and an adjustment means. <Drifted pumice etc. intake structure (0105): Embodiment 1: Mainly corresponds to claim 1>

[0029] As shown in Figure 2, the "drifted pumice, etc. intake structure (0105)" has the function of removing unwanted materials scattered or accumulated on the water surface and sending them out for subsequent processing. One example is a dustpan with a suction port shaped like the handle of a dustpan. When actually used on the water surface, it is possible to use not just one unit, but multiple units lined up closely together. They can also be lined up horizontally or in a V-shape with an open front. The drifted pumice, etc. intake structure can be portable or fixed to a float or other device fixed to the shore and permanently placed on the float. The float can also be configured with its own propulsion so that it can move freely on the water surface. The float can be of any type, as long as it has buoyancy and floats on the water surface. It can be a combination of multiple hollow plastic blocks, a boat, a ship, or a float.

[0030] <Depth restriction unit (0101): Embodiment 1: Mainly corresponds to claim 1>

[0031] The "depth restriction unit (0101)" has the function of restricting the depth of the suction water surface. The pumice and other suction port (described later) uses a pump or ejector to suck in unwanted objects in front of it, but if the area in the water where the suction flow occurs is too wide, it will not be able to effectively suck in the floating unwanted objects. Since the depth to which unwanted objects, such as pumice, plastic, and aquatic organisms, sink below the sea surface is roughly determined by their type, the depth restriction unit is provided to restrict the area in which the suction flow occurs while leaving some margin. The depth restriction unit is typically a plate-shaped structure as shown in Figure 1, but may be block-shaped or have other shapes without being limited to this.

[0032] The depth restriction unit may also be configured so that its vertical position can be adjusted relative to the opening restriction unit described below. For example, the opening restriction unit may have multiple parallel grooves on the inside, and the vertical position can be adjusted depending on which groove the depth restriction unit is inserted into. The vertical position may also be adjusted by a drive mechanism such as a motor. The width of the depth restriction unit can be designed to range from approximately 50 centimeters to 10 meters depending on the degree of dispersion and concentration of the floating objects and the size of the floating objects. If it is plate-shaped, a metal plate can be used. The length of the depth restriction unit can also be designed, similar to the width, from approximately 70 centimeters to 2 meters depending on the case. The typical shape of the depth restriction unit is a rectangle or trapezoid with its length longer than its width.

[0033] <Opening degree regulation unit (0102a, 0102b): Embodiment 1: Mainly corresponds to claim 1>

[0034] The "opening degree regulating units (0102a, b)" have the function of regulating the opening degree of the suction water surface. The opening degree of the suction water surface has the function of regulating the width between one opening degree regulating unit (0102a) and the other opening degree regulating unit (0102b), and the function of regulating the angle between one opening degree regulating unit (0102a) and the other opening degree regulating unit (0102b). In the example of Figure 1, the opening degrees are parallel, but they can also be configured in an inverted V shape, for example, so that the width between the two becomes wider toward the front. The opening degree regulating unit can also be configured with a variable opening degree, which allows the opening degree to be adjusted and optimized depending on the type of floating matter.

[0035] The opening can be adjusted manually or motor-driven. The height of the opening limiter is approximately 30 centimeters to 1 meter, and the optimal value can be selected depending on the type of floating objects and the depth of accumulation below the water surface. The opening limiter must be designed and positioned so that its top edge does not sink below the water surface when the depth limiter is positioned at the appropriate depth below the water surface. This would prevent accurate capture of floating objects. The optimal height of the opening limiter depends on the calmness of the water surface. In wavy waters such as the ocean or large lakes, the opening limiter must be set higher than the wave height. This is because once the target object, such as drifting pumice, is taken into the intake structure, it may be swept away by the waves. Therefore, it is preferable that the height of the opening limiter be adjustable depending on the wave height of the day.

[0036] <Suction opening (0103): Embodiment 1: Mainly corresponds to claim 1>

[0037] The "suction opening (0103)" is configured forward by a depth restriction section and an opening restriction section. "Forward" refers to the direction where floating debris such as pumice is located. Because it is configured with a depth restriction section and an opening restriction section, its width is approximately 50 centimeters to 10 meters, and its height is approximately 30 centimeters to 1 meter. The suction opening can also be configured with a fence to prevent floating debris larger than the target object from being sucked in. Furthermore, a crusher to crush floating debris can be installed in front of or near the suction opening. This is to prevent the pumice suction port, described below, from becoming clogged with sucked floating debris. Furthermore, to ensure that the downstream pipes and hoses are free of floating debris upon completion of the suction process, a fine fence that can be freely opened and closed to allow only seawater to pass through, or a structure that can hold a filter, can also be installed.

[0038] <Pumice stone suction port (0104): Embodiment 1: Mainly corresponds to claim 1>

[0039] The "pumice etc. suction port (0104)" is a floating object suction port located behind the depth restriction unit and the opening restriction unit, and is the port through which floating objects are sucked in through a connected pipe or hose and sent out for post-processing. The pumice etc. suction port can generate an efficient suction flow by configuring the rear of the drifting pumice etc. intake structure in a funnel shape so that floating objects are efficiently concentrated. It is also preferable to provide a lid on the box-shaped body of the drifting pumice etc. intake structure in front of the pumice etc. suction port to reduce the amount of air flowing into the pumice etc. suction port. Furthermore, it is preferable to position the inner wall surface that forms the upper part of the pumice etc. suction port below the water surface, again to reduce the inflow of air.

[0040] Therefore, it is preferable that the funnel-shaped rear structure is configured so that its height gradually decreases. In other words, it is preferable that the funnel-shaped rear structure is configured so that the height between the top and bottom gradually decreases. It can also be configured so that the bottom side gradually rises. The cross-sectional area of the pumice stone or other suction port is preferably about 10 cm x 10 cm (not limited to rectangular) to about 50 cm x 50 cm (not limited to rectangular). It can be designed appropriately depending on the diameter of the pipe or hose connected thereto and the size of the object to be suctioned.

[0041] <Depth maintaining unit (0601, 0602): Embodiment 1: mainly corresponds to claims 2 and 4>

[0042] The "depth maintaining unit" (0601, 0602) has the function of maintaining the depth restricting unit of the drifting pumice and other inlet structure at a predetermined position below the sea surface. As mentioned above, the depth restricting unit is a functional part for restricting the depth of the underwater suction area, and the placement depth of the depth restricting unit must be determined depending on how deep the drifting pumice and other particles are distributed below the water surface. Therefore, the drifting pumice and other inlet structure must have the function of maintaining the depth of the depth restricting unit during operation.

[0043] In the example shown in Figure 6, the upper and lower hoisting pipes (0601) fixed to the drifting pumice intake structure are fixed on a float floating on the water surface. The hoisting amount of the hoisting rope attached to the upper and lower hoisting pipes is adjusted (by the adjusting means) by the hoisting winch to maintain a fixed hoisting amount, thereby maintaining the underwater position of the drifting pumice intake structure and, ultimately, the depth control unit. The upper and lower hoisting pipes may be solid or hollow. Furthermore, the vertical movement of the upper and lower hoisting pipes is not limited to that achieved by the hoisting rope. It may be achieved by rotating wheels attached closely to the upper and lower hoisting pipes, or by other means for vertical movement and fixation. In locations with strong vertical wave movement, the depth control unit may be configured to move up and down in synchronization with the vertical movement of the waves. The wave height is detected and synchronized by a motor or other device.

[0044] <Guiding part (0401): Embodiment 1: Mainly corresponds to claim 3>

[0045] FIG. 4 shows an intake structure for drifting pumice and the like according to this embodiment, which includes a guide portion. The guide portion functions similarly to a silt fence, which will be described later, but differs from a silt fence in that it uses a physical force to guide drifting and floating objects, such as drifting pumice, into the suction opening of the intake structure for drifting pumice and the like. One example of a force used as a physical force is a jet of seawater or the like. However, this is not limited to this, and the force may be a waterwheel or the like that is provided in front of the suction opening and sends floating objects into the suction opening with its blades, or a shovel or the like that sends floating objects into the suction opening. The guide portion physically forces floating objects, such as pumice, into the suction opening, thereby strengthening the force that sends drifting and floating objects into the suction opening in addition to the suction force of the pumice and the like suction opening, thereby enabling the drifting pumice and the like to be efficiently taken into the suction opening.

[0046] When using the jet stream (0404) shown in Fig. 4, for example, high-pressure seawater is sent from a seawater jet pump placed in seawater via a high-pressure hose (0402) to a jet nozzle (0403), and the jet stream (0404) is sprayed from the jet nozzle toward the suction opening (0405). The jet nozzle is preferably placed at a position equal to or lower than the depth below the water surface of the floating objects such as the drifting pumice, so as to prevent the drifting objects such as the pumice from obstructing the waterway leading to the suction opening, and the jet stream is sprayed toward the suction opening located diagonally above, creating a current in the area of the sea surface where the drifting pumice is present.

[0047] It is preferable to have multiple jet nozzles that emit jet streams. This is because it is necessary to create a band-like flow with a width that matches the width of the suction opening. The jet nozzles may also be arranged in a fan shape so that they converge toward the suction opening. This is because it is possible to concentrate drifting debris such as pumice toward the suction opening from a wider area. The distance between the tip of the jet nozzle and the suction opening should be approximately 20 centimeters to 1 meter. It is preferable to increase the distance as the size of the drifting debris increases. The distance must be at least greater than the average size of the drifting debris.

[0048] <Embodiment 2>

[0049] <Embodiment 2 Overview and Configuration>

[0050] Embodiment 2 is a drifting pumice removal device. The drifting pumice removal device is a device that includes the drifting pumice intake structure described in any one of Embodiments 1 as part of its configuration, and in addition to the drifting pumice intake structure, is equipped with one or more of a forced movement device, a suction device, a float device, a silt fence, and a sieve device.

[0051] <Forced movement device (0702): Embodiment 2: Mainly corresponds to claim 5>

[0052] FIG. 7 shows a drifting pumice removal device comprising a forced-movement device (0702) and the drifting pumice intake structure described in any one of the first embodiments. The guidance unit described in the first embodiment has a similar configuration to the forced-movement device. The guidance unit uses physical force to send drifting objects toward the suction opening of the drifting pumice intake structure in front of the suction opening, while the forced-movement device of this embodiment is a device for sending drifting objects such as pumice toward the suction opening from well in front of the suction opening. Various forced-movement devices are conceivable, but a typical example is a vessel equipped with a water cannon. The water cannon is configured to collect drifting objects in the drifting pumice intake structure located forward. Furthermore, when a silt fence, as described below, is used, it is conceivable to forcibly move drifting pumice from outside the silt fence area toward the silt fence area using a forced-movement device such as a water cannon.

[0053] Another possible configuration is to create a wall on the sea surface using an oil fence or silt fence and pull it toward land. It is also possible to use a beach seine with floats to pull floating objects such as pumice toward land. When using a fishing net, it is also possible to secure the ends of the net with two fishing boats and move it toward the intake structure for drifting pumice, etc. In this case, the silt fence, which will be explained later, can be stretched in a V-shape toward the suction opening of the intake structure for drifting pumice, etc., and the fishing boats can move the fishing net, which is attached to the inside of the silt fence, from the outside toward the shore.

[0054] <Suction device (0703a, 0703b or 0502, 0503): Embodiment 2: mainly corresponds to claims 6 and 8>

[0055] 5 and 7 are diagrams showing a drifting pumice removal device comprising a suction device and the drifting pumice intake structure described in any one of the first embodiments. If floating matter such as pumice and plastics is sucked directly through the pump, it may damage the pump structure. Therefore, it is appropriate to use an ejector to send the suctioned matter, such as pumice, to post-treatment rather than passing it directly through the pump. The suction device of this embodiment comprises an ejector for sucking the pumice through the pumice intake and a driving fluid pump for driving the ejector. The driving fluid used is seawater, lake water, river water, or the like, in which floating matter floats. It is also possible to reuse the seawater separated from the pumice by the sieving device described below.

[0056] The suction device described in claim 6 is combined with the intake structure for drifting pumice etc. described in any one of embodiment 1, while the suction device described in claim 8 is added to the drifting pumice etc. removal device described in claim 5 or claim 7. That is, the drifting pumice etc. removal device is either the drifting pumice etc. intake structure described in any one of embodiment 1, a forced movement device, and a suction device, or the drifting pumice etc. removal device is the drifting pumice etc. intake structure described in any one of embodiment 1, a float device described later, and a suction device.

[0057] <Float device (0301, 0504, 0603 or 0704): Embodiment 2: Mainly corresponds to claim 7>

[0058] The "float device (also called a barge float)" has a support part for supporting the intake structure for drifting pumice and other debris and its accessories, and is designed to float on the water surface. The depth maintenance part, guidance part, and depth maintenance part adjustment means of embodiment 1 are supported and installed on this float device. The float device need only be buoyant, and may be a simple plastic block, or may be a boat, raft, or ship. It may also be provided with propulsion. It is also preferable that the float device be equipped with a fixing means for fixing it to the coast, quay, seabed, or bottom of the water.

[0059] It is preferable that the device be configured so that it can be secured to a fixed object on land with a metal rod or rope, or so that it can be secured to the seabed by lowering an anchor. If necessary, it is also preferable that it has a silt fence securing means for securing the silt fence described below. The silt fence securing means preferably functions to connect the silt fence to the left and right sides of the suction opening.

[0060] <Silt fence (0705): Embodiment 2: Mainly corresponds to claim 9>

[0061] The "silt fence" is arranged to guide drifting pumice and the like toward the suction opening of the drifting pumice and the like intake structure, so that the pumice and the like can be removed with as high a yield as possible. The forcing movement device described above may also be configured and operated to forcibly move the pumice and the like to the area surrounded by the silt fence.

[0062] <Sieving device (0705): Embodiment 2: Mainly corresponds to claim 9>

[0063] The "sieving device" has the function of separating the seawater and other materials from the pumice and other materials sucked by the suction device and transported through a transport pipe together with the seawater and other materials connected to the suction opening. As described above, a portion of the separated seawater may be configured to be reused as the ejector driving fluid. The pumice and other materials separated from the seawater and other materials by the sieving device may be dropped into a vessel and transported in batch processing. The vessel itself may be replaceable.

[0064] <Embodiment 3>

[0065] <Outline of Embodiment 3>

[0066] This embodiment relates to a method for removing drifting pumice and the like.

[0067] The first is a method for removing drifting pumice and the like, including the step of removing drifting pumice and the like floating on the sea using any one or more of the drifting pumice and the like intake structures of embodiment 1. When a depth-limiting unit, for example, a dustpan-type drifting pumice and the like intake structure is used, the part corresponding to the bottom plate is maintained at a position sufficiently deeper than the subsurface depth of the drifting pumice and the like, and the drifting pumice and the like are guided to a sieve by the suction force of an ejector or the like connected to a pumice and the like suction port, and then separated from seawater and the like and collected in a vessel. The vessel is preferably replaceable and portable, and when the vessel becomes full with pumice and the like, it is replaced with a replacement vessel, and the full vessel is transported by a transport vehicle to a pumice and the like treatment plant.

[0068] The second is a method for removing drifting pumice and the like, including the step of removing drifting pumice and the like floating on the sea surface using one or more of the drifting pumice and the like intake structures of the first embodiment, and the step of removing the pumice and the like while maintaining the upper surface of the depth-restricting portion of the drifting pumice and the like intake structure below the subsurface depth of the pumice and the like floating on the sea surface. Since the subsurface depth of the pumice and the like may fluctuate, the subsurface depth of the pumice and the like is constantly monitored using image analysis or the like, and the depth of the depth-restricting portion is appropriately adjusted to remove the drifting pumice and the like. Constant monitoring methods include image analysis using a camera, as well as a method using a laser sensor. The method using a laser sensor involves installing multiple laser light sources, for example, at 1-centimeter intervals in the depth direction, and a light-receiving sensor that receives laser light from the laser light sources in front of the suction opening, and measuring and determining the depth to which the laser light is blocked.

[0069] The third is a method for removing drifting pumice and the like, which includes the step of removing drifting pumice and the like floating on the sea using one or more of the intake structures for drifting pumice and the like of embodiment 1, and further includes the step of arranging silt fences so that the intervals between them gradually narrow toward the suction opening of the intake structure for drifting pumice and the like. This is a method for removing drifting pumice and the like that can be configured to be performed simultaneously with the first and second embodiments of this embodiment. [Explanation of symbols]

[0070] 0101 Depth regulation section 0102 Opening degree regulation unit 0103 Suction opening 0104 Pumice etc. suction port 0105 Drift pumice intake structure 0301 Float (Barge Float) 0302 Position of the intake structure for drifting pumice etc. relative to the float 0112 Consumption amount acquisition rule storage unit 0401 Jet nozzle structure 0402 Pipe that sends high-pressure seawater to the jet nozzle 0403 Jet nozzle 0404 Jet 0405 Suction opening where the jet stream is directed 0501 Overall view of the drifting pumice removal device 0502 Ejector 0503 Drive pump for ejector drive fluid 0504 Combined Floats 0601 Up and down lifting pipe for moving up and down the intake structure (depth control part) for drifting pumice etc. 0602 Lifting winch for moving the upper and lower hoisting pipe up and down 0603 Float (Barge Float) 0604 Drift pumice intake structure 0605 Hoisting rope 0701 Drifting pumice removal equipment (drifting pumice dredging equipment) 0702 Forced movement devices (e.g., water pumps, fences, nets and fishing boats, etc.) 0703 Suction device (ejector + ejector drive fluid drive pump + power supply, etc.) 0704 Float (Barge Float) 0705 Silt fence 0706 Sieving equipment

Claims

1. a depth limiting portion for limiting the depth of the suction water surface; an opening degree regulating unit for regulating the opening degree of the suction water surface; a suction opening formed in the front by a depth restriction portion and an opening restriction portion, the suction opening having a fence for preventing floating objects larger than the object to be removed from being sucked in; a suction port for pumice etc. disposed behind the depth restriction unit and the opening restriction unit; This is a structure for taking in drifting pumice and other debris.

2. 2. The drifting pumice and other intake structure according to claim 1, further comprising a depth maintaining portion for maintaining the depth regulating portion of the drifting pumice and other intake structure at a predetermined position below the water surface.

3. 3. The drifting pumice and the like intake structure according to claim 1 or 2, further comprising a guide portion provided in front of the suction opening for guiding the drifting pumice and the like to the suction opening.

4. 5. The drifting pumice and other debris intake structure according to claim 1, wherein the depth maintaining section has an adjusting means for adjusting the depth restricting section in the vertical direction.

5. The drifting pumice or the like intake structure according to any one of claims 1 to 4, A drifting pumice removal device comprising: a forced movement device for forcibly moving drifting pumice toward the suction opening of the drifting pumice intake structure.

6. The drifting pumice or the like intake structure according to any one of claims 1 to 4, 1. A suction device comprising: an ejector for sucking pumice etc. from a suction port for pumice etc.; A drifting pumice and other removal device comprising: a drive fluid pump for driving an ejector; and a suction device comprising the drive fluid pump.

7. The drifting pumice or the like intake structure according to any one of claims 1 to 4, A floatation device for floating on the surface of water, A float device having a support part for supporting the intake structure for drifting pumice etc.; A drifting pumice removal device consisting of:

8. 1. A suction device comprising: an ejector for sucking pumice etc. from a suction port for pumice etc.; 8. The drifting pumice and other debris removal device according to claim 5 or claim 7, further comprising a suction device comprising a drive fluid pump for driving the ejector.

9. 9. The drifting pumice and the like removal device according to claim 5, further comprising a silt fence arranged to guide the drifting pumice and the like toward the suction opening of the drifting pumice and the like intake structure.

10. 10. The apparatus for removing drifting pumice and the like according to claim 5, further comprising a sieving device for separating the drifting pumice and the like sucked by the suction device from seawater and the like.

11. A method for removing drifting pumice and the like, comprising the step of removing drifting pumice and the like floating on the sea using the drifting pumice and the like intake structure according to any one of claims 1 to 4.

12. A method for removing drifting pumice, etc. as described in claim 11, which includes a step of lowering the upper surface of the depth-limiting portion of the drifting pumice, etc. intake structure described in any one of claims 1 to 4 below the subsurface depth of the pumice, etc. floating on the sea to remove the floating drifting pumice, etc.

13. A method for removing drifting pumice, etc. as described in claim 11 or claim 12, further comprising a step of arranging silt fences so that the spacing between them gradually narrows toward the suction opening of the drifting pumice, etc. intake structure described in any one of claims 1 to 4.

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