Underwater abandoned fishing net cleaning device

Abstract

The present invention relates to the field of water environmental protection technology, and in particular to an underwater abandoned fishing net cleaning device. The technical problems to be solved are: impurities attached to abandoned fishing nets cannot be cleaned away during cleaning, but instead drift into the ocean, polluting the marine environment; and marine debris on the abandoned fishing nets, caused by pulling on them during cleaning, falls and drifts into the ocean, preventing them from being cleaned and removed from the ocean. The technical solution of the present invention is an underwater abandoned fishing net cleaning device comprising a fixed cylinder and a mechanical clamp, wherein the mechanical clamp is movably connected to the fixed cylinder. The present invention utilizes the mechanical clamp to clamp the loose portions of abandoned fishing nets caught on reefs, and utilizes a mechanical cutter to cut the loose portions, thereby achieving the disposal of the loose portions of abandoned fishing nets caught on reefs. This prevents divers from snagging the loose portions of abandoned fishing nets caught on reefs during handling, resulting in multiple snagging of the abandoned fishing nets on the reefs and increasing the difficulty of cleaning.

Description

Technical Field

[0001] The present invention relates to the technical field of water area environmental protection, and in particular to an underwater abandoned fishing net cleaning device. Background Art

[0002] Fishing net cleaning is an important task in marine environmental protection. Fishing nets are important tools used by fishermen to catch fish. However, some fishing nets often fall into the sea and become abandoned fishing nets because they are not firmly reinforced. As more and more abandoned fishing nets fall into the sea, too many abandoned fishing nets gradually endanger marine life and become traps for marine life on the seabed, causing their death or a decline in their quality of life. The accumulation of fishing nets on the seabed will destroy the habitats of low-lying organisms and affect biodiversity. Therefore, cleaning ships often throw mechanical clamps to the seabed to pick up abandoned fishing nets, but abandoned fishing nets are often caught on seabed reefs due to their porous shape. In this scenario, divers usually dive to the seabed to clean up fishing nets that are caught on reefs. Abandoned fishing nets have been deposited on the seabed for a long time, and a large amount of impurities are attached to the fishing nets. When cleaning the abandoned fishing nets, the impurities attached to the fishing nets are often scattered in the ocean as the divers clean them, causing pollution to the marine environment. In addition, existing cleaning methods often use mechanical clamps to directly lift the abandoned fishing nets onto the ship. However, when the fishing nets fall into the ocean, the marine debris in the seawater is caught by the fishing nets. When the abandoned fishing nets are pulled, the marine debris on them falls and scatters in the seawater, and cannot be taken away from the ocean with the abandoned fishing nets. Summary of the Invention

[0003] In order to overcome the shortcomings of discarded fishing nets, in which impurities attached to the nets cannot be cleaned away and are scattered in the ocean, causing pollution to the marine environment, and in which marine debris on the discarded fishing nets falls and is scattered in the ocean due to pulling the discarded fishing nets during cleaning and cannot be cleaned up and taken away from the ocean, the present invention provides an underwater discarded fishing net cleaning device.

[0004] The technical solution of the present invention is: an underwater abandoned fishing net cleaning device, comprising a fixed cylinder, a mechanical clamp and an annular electric slide rail; the fixed cylinder is movably connected with the mechanical clamp, and a plurality of fixing parts are provided on the outside of the fixed cylinder, and the fixing parts are protrusions with vertical through grooves; the mechanical clamp is provided with a connecting block for connecting a hanging rope; the fixed cylinder is also provided with a connecting block for connecting a selection rope; an annular electric slide rail is fixedly connected to the outside of the fixed cylinder; it also includes an adaptive drive member, a mechanical cutter and a pushing drive member; the adaptive drive member is fixedly connected to the slider of the annular electric slide rail; the adaptive drive member is composed of a rotating shaft and an electric push rod, and the rotating shaft is externally connected to a motor; a connecting seat is rotatably connected to the telescopic part of the adaptive drive member, and the connecting seat has a built-in motor that can drive the connecting seat to rotate; a pushing drive member is fixedly connected to the connecting seat, and the pushing drive member is fixedly connected to the mechanical cutter.

[0005] Furthermore, the mechanical clamp consists of a rotator and a clamper. The rotator of the mechanical clamp is movably connected to the fixed cylinder, and the clamper of the mechanical clamp is installed on the rotating part of its rotator; the fixed part of the mechanical clamp rotator is connected to the connecting block.

[0006] Furthermore, a tooth block is provided on the clamping surface of the clamp of the mechanical clamp.

[0007] Furthermore, it also includes a filter plate, a filter cover and a water suction pipe; the filter plate is fixedly connected to the lower end of the fixed cylinder, the filter plate has the ability to deform, and a number of large filter holes are opened on the filter plate; the filter cover is fixedly connected to the top of the filter plate, the filter cover has the ability to deform, the filter cover and the filter plate form an independent space, and a number of winding rods are provided in the filter cover, and a large number of curved and staggered filter wires are provided on the surface of the winding rods; a water suction pipe is provided through the filter cover.

[0008] Furthermore, it also includes a pressing claw; a plurality of pressing claws are fixedly connected to the fixed cylinder, and the fixed cylinder is connected to a driving motor for driving the pressing claws to rotate.

[0009] Furthermore, a plurality of deformable metal strips are provided on the side of the filter plate that contacts the pressing claws, and the pressing claws correspond to the metal strips one by one.

[0010] Furthermore, it also includes a fixing hook; a plurality of fixing hooks are provided on the adaptive driving member.

[0011] Furthermore, the fixing hook is connected to the adaptive driving member by a spring.

[0012] Furthermore, the filter cover is hemispherical.

[0013] Furthermore, the large filter holes are distributed in a ring array.

[0014] The beneficial effects are as follows: the present invention uses a mechanical clamp to clamp the loose parts of the abandoned fishing net caught on the reef, and uses a mechanical cutter to cut the loose parts of the abandoned fishing net, thereby achieving the processing of the loose parts of the abandoned fishing net caught on the reef, avoiding the loose parts being caught on the reef when divers handle the abandoned fishing net caught on the reef, resulting in the abandoned fishing net being caught on the reef in multiple places, which increases the difficulty of cleaning;

[0015] By using the mechanical clamp to rotate, the loose parts of the abandoned fishing net caught on the reef are twisted into a hemp rope. This avoids the situation where the mechanical cutter cannot directly cut the abandoned fishing net, requiring multiple cuts, reducing work efficiency, and the abandoned fishing net is too large, requiring divers to cut around the abandoned fishing net multiple times.

[0016] The waste fishing net impurities are filtered through the filter plate and filter cover, so as to collect the waste fishing net impurities and prevent the impurities on the waste fishing net from being scattered in the sea and polluting the ocean.

[0017] By fixing the cut ends of the discarded fishing nets with fixed hooks, the discarded fishing nets can be collected and transported to the cleaning ship in the form of hemp ropes for cleaning, avoiding the direct lifting of the cut discarded fishing nets onto the cleaning ship, which may cause the discarded fishing nets to be caught on other reefs during the lifting process, and the marine garbage caught in the discarded fishing nets to be pulled away from the discarded fishing nets during cleaning, and drift in the ocean, polluting the ocean. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the three-dimensional structure of the underwater abandoned fishing net cleaning device of the present invention;

[0019] Figure 2 This is a schematic diagram of the combined three-dimensional structure of the adaptive arm, mechanical cutter and driving member of the present invention;

[0020] Figure 3 A partial cross-sectional view of the underwater abandoned fishing net cleaning device of the present invention;

[0021] Figure 4 This is a schematic diagram of the three-dimensional structure of the filter plate and filter cover combination of the present invention;

[0022] Figure 5 This is a schematic diagram of the three-dimensional structure of the large filter hole and the mechanical arm combination of the present invention;

[0023] Figure 6 For the present invention Figure 5 A magnified view of the area A in FIG;

[0024] Figure 7 This is a diagram showing the changing states of the filter plate and filter cover of the present invention.

[0025] The names and serial numbers of the parts in the figure are: 1-fixed cylinder, 2-mechanical clamp, 3-adaptive drive member, 4-mechanical cutter, 101-push drive member, 102-annular electric slide rail, 201-filter plate, 20101-large filter hole, 202-filter cover, 203-water suction pipe, 204-pressing claw, 205-fixing hook, 206-metal strip. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] like Figure 1-Figure 3 and Figure 7As shown, an underwater abandoned fishing net cleaning device includes a fixed cylinder 1, a mechanical clamp 2 and an annular electric slide rail 102; the mechanical clamp 2 is movably connected to the fixed cylinder 1, and two fixing parts are provided on the outside of the fixed cylinder 1, and the fixing parts are protrusions with vertical through grooves; a connecting block for connecting a hanging rope is provided on the mechanical clamp 2; a connecting block for connecting a selection hanging rope is also provided on the fixed cylinder 1; an annular electric slide rail 102 is fixedly connected to the outside of the fixed cylinder 1.

[0029] It also includes an adaptive drive member 3, a mechanical cutter 4 and a pushing drive member 101; the adaptive drive member 3 is bolted to the slider of the annular electric slide rail 102; the adaptive drive member 3 is composed of a rotating shaft and an electric push rod, and the rotating shaft is externally connected to a motor; the telescopic part of the adaptive drive member 3 is rotatably connected to a connecting seat, and the connecting seat has a built-in motor that can drive the connecting seat to rotate; the connecting seat is bolted to the pushing drive member 101, which is an electric push rod, and the pushing drive member 101 is bolted to the mechanical cutter 4; the sliding block is driven by the annular electric slide rail 102 to drive the adaptive drive member 3 to rotate outside the fixed cylinder 1 to cut off the discarded fishing net.

[0030] The mechanical clamp 2 consists of a rotator and a clamper. The rotator of the mechanical clamp 2 is movably connected to the fixed cylinder 1, and the clamper of the mechanical clamp 2 is installed on the rotating part of its rotator; the fixed part of the rotator of the mechanical clamp 2 is connected to the connecting block; by controlling the mechanical clamp 2 to rotate in the rotating part, the fishing net clamped by the mechanical clamp 2 rotates with the mechanical clamp 2, and at this time the other end of the fishing net is caught by the reef, preventing it from rotating with the mechanical clamp 2. In this case, the abandoned fishing net is twisted into a hemp rope.

[0031] The clamping surface of the clamp of the mechanical clamp 2 is provided with tooth blocks; the tooth blocks on the mechanical clamp 2 increase the friction force when clamping the discarded fishing net, thereby preventing the discarded fishing net from slipping when clamped by the mechanical clamp 2.

[0032] The underwater abandoned fishing net cleaning device is referred to as the cleaning device below, and the cleaning device is described as follows: first, the location of the reef is detected by sonar and camera, and whether there are abandoned fishing nets on the reef surface is determined, and the data is transmitted to the cleaning ship. Then, the personnel on the cleaning ship will drive the cleaning ship to the abandoned fishing net based on the data, and the cleaning diver will dive to the seabed. The cleaning diver will specifically determine whether the abandoned fishing net is completely entangled on the reef or partially entangled on the reef. If the abandoned fishing net is completely entangled on the reef, it will be manually handled by the cleaning diver. If the abandoned fishing net is not completely entangled on the reef, the abandoned fishing net that is not caught on the reef will be handled by the cleaning equipment.

[0033] First, the abandoned fishing net cleaning personnel on the cleaning boat will fix the cleaning device on the reel on the cleaning boat through four steel wire ropes, two of which are fixed on the mechanical clamp 2, and two steel wire ropes are fixed on the fixed drum 1. The motor is started to drive the reel to rotate. Through the rotation of the reel, the four steel wire ropes fixed on the cleaning device and the cleaning device fixed thereto are lowered to the seabed to the abandoned fishing net that is not caught by the reef. At this time, the mechanical clamp 2 is located at the upper end of the fixed drum 1. When the cleaning device enters the seabed, it passes through the outer surface of the fixed drum 1 through the two hard rods lowered from the boat. The vertical groove on the convex block on the side is used to prevent the device from floating and rotating. Then the reel is driven to lower the two steel wire ropes connected to the mechanical clamp 2, and the mechanical clamp 2 is lowered to the abandoned fishing net to clamp the abandoned fishing net. Then the personnel on the cleaning boat start the reel to reel in the two steel wire ropes that fix the mechanical clamp 2. At this time, the position of the fixed cylinder 1 remains unchanged, and the mechanical clamp 2 is lifted upward in the fixed cylinder 1. The mechanical clamp 2 clamps the abandoned fishing net and drags it into the fixed cylinder 1. At the same time, the motor in the mechanical clamp 2 is driven to rotate the rotator of the mechanical clamp 2. At this time, the clamp of the mechanical clamp 2 As the fixed cylinder 1 rotates, the abandoned fishing net clamped by the mechanical clamp 2 is also driven to rotate together. At this time, the abandoned fishing net is partially caught by the reef and the other part is clamped by the mechanical clamp 2. Driven by the rotation of the mechanical clamp 2 and the reef's resistance to its movement, the scattered part of the abandoned fishing net is twisted into a hemp rope in the fixed cylinder 1. Since one end of the abandoned fishing net is caught by the reef, the entire cleaning device is subjected to the reaction force of the twisting and approaches the reef. The abandoned fishing net is twisted into a hemp rope and is driven by the rotation of the mechanical clamp 2 to rotate continuously, so that the abandoned fishing net is in a Tighten the straightened state, at this time the annular electric slide rail 102 drives the slider connected to the adaptive drive member 3 to drive the adaptive drive member 3 to rotate to the stretched position of the abandoned fishing net, and the motor in the adaptive drive member 3 drives the rotating shaft connected to the slider to drive the electric push rod of the adaptive drive member 3 to rotate, at this time the electric push rod of the adaptive drive member 3 rotates from the original vertical state to the inclined downward state, and then drives the motor of the connecting seat, at this time the connecting seat pushes the drive member 101 to extend toward the stretched position of the abandoned fishing net, and pushes the drive member 101 to drive the mechanical cutter 4 connected thereto to extend toward the stretched position of the abandoned fishing net, as shown in FIG. Figure 7As shown, the annular electric slide rail 102 then drives the slider connected to the adaptive drive member 3 to drive the adaptive drive member 3 to rotate back and forth, and the adaptive drive member 3 itself adapts to the expansion and contraction and angle adjustment, pushing the drive member 101 to adapt to the expansion and contraction, so that the mechanical cutter 4 always keeps in contact with the abandoned fishing net to directly cut the abandoned fishing net twisted into a hemp rope shape. The above work process assists divers in handling the scattered parts of the fishing net, and avoids the scattered parts of the fishing net being caught on the reef again during the process of divers handling the abandoned fishing net caught on the reef, resulting in the abandoned fishing net being caught on the reef in multiple places, increasing the difficulty of cleaning, and when cleaning the scattered abandoned fishing net, the mechanical clamp 2 and the reef abandoned fishing net are used to twist the scattered parts into a hemp rope shape to avoid the abandoned fishing net not being caught on the reef. The parts are scattered in the sea water, and the abandoned fishing net cannot be cut off in a concentrated manner, and multiple cuttings are required. Divers need to collect the abandoned fishing net for a long time.

[0034] Example 2

[0035] On the basis of Example 1, Figure 4-Figure 7 As shown, it also includes a filter plate 201, a filter cover 202 and a water suction pipe 203; the filter plate 201 is bolted to the lower end of the fixed cylinder 1, the filter plate 201 has the ability to deform, and a plurality of large filter holes 20101 are opened on the filter plate 201; a filter cover 202 is fixedly connected to the top of the filter plate 201, the filter cover 202 has the ability to deform, the filter cover 202 and the filter plate 201 form an independent space, and a plurality of winding rods are provided in the filter cover 202, and a large number of curved and staggered filter wires are provided on the surface of the winding rods; a water suction pipe 203 is provided through the filter cover 202; a water pump connected to the water suction pipe 203 is used to extract impurity-containing seawater from the bottom of and around the filter plate 201, and the seawater containing impurities enters the filter plate 201 from the large filter holes 20101, and the impurities in the seawater are filtered and retained by the filter wires on the filter cover 202 in the chamber formed by the filter plate 201 and the filter cover 202.

[0036] It also includes a pressing claw 204; four pressing claws 204 in a ring array are bolted to the fixed cylinder 1, and the fixed cylinder 1 is connected to a driving motor for driving the pressing claws 204 to rotate; the filter plate 201 is pressed downward by the pressing claws 204, and the filter plate 201 drives the filter cover 202 to form a bowl shape to absorb impurities attached to the fishing net when the fishing net is cut.

[0037] Four deformable metal strips 206 are provided on a surface of the filter plate 201 that contacts the pressing claws 204 , and the pressing claws 204 correspond to the metal strips 206 one by one.

[0038] It also includes a fixing hook 205 ; three fixing hooks 205 are provided on the adaptive driving member 3 .

[0039] After the fixing hook 205 is connected to the adaptive driving member 3 with a spring, the spring's tensile properties are utilized to adaptively stretch and deform as the abandoned fishing net swings back and forth with the flow of seawater, thereby reducing the constantly changing pulling force on the adaptive driving member 3 and protecting the adaptive driving member 3.

[0040] The filter cover 202 is hemispherical, which makes it easier for the equipment to pull the abandoned fishing nets to the cleaning ship and reduce the resistance caused by seawater.

[0041] The large filter holes 20101 are arranged in a circular array. As abandoned fishing nets are deposited on the seabed and soaked in seawater, they age. When the mechanical clamp 2 clamps and twists the scattered parts of the abandoned fishing nets, the abandoned fishing nets in the twisting area will be subjected to a significant twisting force, causing the aged abandoned fishing nets to break and scatter into a large number of fragments, which are scattered in the surrounding seawater, affecting the survival of marine life. Before the cleaning device is lowered, the water pump 203 located on the filter cover 202 is connected to an external water pump. When the mechanical clamp 2 clamps the abandoned fishing nets, the personnel on the cleaning boat start the water pump, and the water pump 203 connected to the water pump begins to pump the surrounding seawater into the water pump 203. At this time, because the scattered parts of the abandoned fishing nets are still Since it is in the open state, the area where debris may be generated is relatively large. Therefore, the filter plate 201 is kept in a flat and unfolded state, the suction range of the large filter hole 20101 is expanded, and the fishing net fragments are captured over a large area. Due to the extraction of the suction pipe 203, the seawater containing the discarded fishing net fragments enters the filter cover 202 from the large filter hole 20101 of the filter plate 201. When the seawater containing the discarded fishing net fragments enters the suction pipe 203 through the filter cover 202, the filter wire in the filter cover 202 absorbs and intercepts the discarded fishing net fragments in the seawater, and the filtered seawater flows from the suction pipe 203 to the suction pump, and the suction pump discharges the filtered seawater back into the sea.

[0042] The discarded fishing net is twisted into a hemp rope shape and then cut and put into the fixed cylinder 1. At this time, the pressing claw 204 is driven to gather toward the center below the fixed cylinder 1. When the pressing claw 204 gathers, the filter plate 201 connected to it and the filter cover 202 connected to the filter plate 201 are deformed to the shape of Figure 7 In the state shown, the motor drives the adaptive drive member 3 to drive the mechanical cutter 4 together, and drives the adaptive drive member 3 and the mechanical cutter 4 to slide on the annular electric slide rail 102. Figure 7As shown, the mechanical cutter 4 is driven to extend toward the abandoned fishing net, and the fixed hook 205 is located in front of the mechanical cutter 4 at this time. During the cutting process of the mechanical cutter 4, the fixed hook 205 located in the front hooks the part of the abandoned fishing net close to the part clamped by the mechanical clamp 2, thereby limiting and fixing the abandoned fishing net at the cutting end, ensuring that the abandoned fishing net hooked by the fixed hook 205 maintains the shape of a hemp rope. At this time, the fixed hook 205 acts as a reef to fix the abandoned fishing net, so that it does not spread out due to being cut by the mechanical cutter 4. Because the abandoned fishing net has been on the seabed for a long time, in addition to its own aging fragments, its surface will also collect some other garbage. By twisting the abandoned fishing net into a hemp rope shape, these garbage can be bound inside the hemp rope to prevent the garbage from falling from the abandoned fishing net during the lifting process.

[0043] After the cutting is completed, one end of the cut abandoned fishing net is fixed by the mechanical clamp 2, and the other end is hooked and fixed by the fixing hook 205, and is located in the fixing cylinder 1 in the shape of a hemp rope. The personnel on the cleaning boat start the reel to lift the cleaning device onto the boat, and take out the abandoned fishing net brought out of the device after lifting it onto the boat. The above work flow realizes the filtering treatment of impurities attached to the abandoned fishing net, thereby preventing impurities on the abandoned fishing net from being scattered in the sea when the abandoned fishing net is cleaned, polluting the ocean, and using the abandoned fishing net twisted into a hemp rope to wrap other marine garbage on the abandoned fishing net and take it away from the ocean, thereby preventing the marine garbage caught in the abandoned fishing net from being pulled away from the abandoned fishing net during cleaning, floating in the ocean, and polluting the ocean.

[0044] The large filter holes 20101 are distributed in a circular array.

[0045] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An underwater abandoned fishing net cleaning device, comprising a fixed cylinder (1), a mechanical clamp (2) and an annular electric slide rail (102); the fixed cylinder (1) is movably connected to the mechanical clamp (2), and a plurality of fixing parts are provided on the outside of the fixed cylinder (1), and the fixing parts are protrusions with vertical through grooves; a connecting block for connecting a hanging rope is provided on the mechanical clamp (2); a connecting block for connecting a hanging rope is also provided on the fixed cylinder (1); an annular electric slide rail (102) is fixedly connected to the outside of the fixed cylinder (1); the characteristics are: The invention also includes an adaptive driving member (3), a mechanical cutter (4) and a pushing driving member (101); the adaptive driving member (3) is fixedly connected to the slider of the annular electric slide rail (102); the adaptive driving member (3) is composed of a rotating shaft and an electric push rod, and the rotating shaft is externally connected to a motor; a connecting seat is rotatably connected to the telescopic part of the adaptive driving member (3), and the connecting seat has a built-in motor that can drive the connecting seat to rotate; the pushing driving member (101) is fixedly connected to the connecting seat, and the mechanical cutter (4) is fixedly connected to the pushing driving member (101).

2. The underwater abandoned fishing net cleaning device according to claim 1, characterized in that: The mechanical clamp (2) consists of a rotator and a clamp. The rotator of the mechanical clamp (2) is movably connected to the fixed cylinder (1). The clamp of the mechanical clamp (2) is installed on the rotating part of the rotator. The fixed part of the rotator of the mechanical clamp (2) is connected to the connecting block.

3. The underwater abandoned fishing net cleaning device according to claim 2, characterized in that: A tooth block is provided on the clamping surface of the clamp of the mechanical clamp (2).

4. The underwater abandoned fishing net cleaning device according to claim 3, characterized in that: The filter housing (202) further comprises a filter plate (201), a filter cover (202) and a water extraction pipe (203); the filter plate (201) is fixedly connected to the lower end of the fixed cylinder (1); the filter plate (201) has a deformable capacity, and a plurality of large filter holes (20101) are provided on the filter plate (201); a filter cover (202) is fixedly connected above the filter plate (201); the filter cover (202) has a deformable capacity, the filter cover (202) and the filter plate (201) form an independent space, and a plurality of winding rods are provided in the filter cover (202), and a large number of bent and interlaced filter threads are provided on the surface of the winding rods; a water extraction pipe (203) is provided through the filter cover (202).

5. The underwater abandoned fishing net cleaning device according to claim 4, characterized in that: It also includes pressing claws (204); a plurality of pressing claws (204) are fixedly connected to the fixed cylinder (1), and the fixed cylinder (1) is connected to a driving motor for driving the pressing claws (204) to rotate.

6. The underwater abandoned fishing net cleaning device according to claim 5, characterized in that: A plurality of deformable metal strips (206) are provided on a side of the filter plate (201) that contacts the pressing claw (204), and the pressing claw (204) corresponds to the metal strips (206) one by one.

7. The underwater abandoned fishing net cleaning device according to claim 1, characterized in that: It also includes a fixing hook (205); a plurality of fixing hooks (205) are provided on the adaptive driving member (3).

8. The underwater abandoned fishing net cleaning device according to claim 7, characterized in that: The fixing hook (205) is connected to the adapting drive member (3) by a spring.

9. The underwater abandoned fishing net cleaning device according to claim 4, characterized in that: The filter cover (202) is hemispherical.

10. The underwater abandoned fishing net cleaning device according to claim 4, characterized in that: The large filter holes (20101) are distributed in a ring array.

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