A watering device for tree breeding

Abstract

The application discloses a watering device for forest tree breeding and relates to the technical field of watering devices.The watering device comprises a unmanned aerial vehicle body, a machine arm is installed on the unmanned aerial vehicle body, a wing is installed at the end of the machine arm, a watering mechanism is arranged on the unmanned aerial vehicle body, the watering mechanism comprises a mounting chamber, a liquid tank is installed in the mounting chamber, a plurality of rib plates are arranged on the inner side of the bottom of the liquid tank, the rib plates divide the bottom of the liquid tank into a plurality of liquid grooves, a plurality of main liquid bags are installed on the top of the rib plates, the main liquid bags and the liquid grooves are in one-to-one correspondence, and the main liquid bags and the liquid grooves cooperatively form liquid cavities for containing liquid, and the bottom of the liquid groove is connected with a spray head through a communication assembly.The main liquid bags and the liquid grooves are matched in the form of multiple partitions, can work based on the extrusion assembly, uniformly press the main liquid bags downward, make liquid be discharged from the spray head, better control the liquid spraying amount of each spray head to be consistent, and avoid the situation that liquid spraying is uneven due to slight blockage or other factors of a certain spray head.

Description

Technical Field

[0001] This invention relates to the field of irrigation equipment technology, and in particular to an irrigation equipment for forest tree breeding. Background Technology

[0002] Irrigation is a crucial step in the forest seedling cultivation process, affecting the survival rate and growth quality of seedlings. Traditional forest irrigation methods mainly rely on manual backpack sprayers or ground irrigation equipment, which is not only labor-intensive and inefficient, but also makes it difficult to achieve uniform and timely irrigation for large areas and complex terrains in seedling cultivation.

[0003] In recent years, drone technology has been increasingly applied to agricultural and forestry plant protection and irrigation due to its advantages such as high mobility, lack of terrain limitations, and high operational efficiency. Existing drone irrigation systems typically integrate the liquid tank and nozzles onto the drone platform, using a pump or gravity to deliver liquid to the nozzles for spraying. However, in practical use, these systems still have the following problems: Existing drone irrigation systems mostly employ a single liquid chamber combined with multiple nozzles, with each nozzle sharing the same liquid path. Due to factors such as changes in the drone's attitude during flight, differences in the resistance of the nozzle's pipeline, and minor blockages in individual nozzles, the actual liquid output of different nozzles can easily vary significantly, resulting in over-irrigation in some areas and under-irrigation in others.

[0004] Some improvement solutions attempt to achieve multiple liquid outlets through diversion valves or independent pump control, but this increases the complexity of the system and the risk of failure. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an irrigation device for forest tree breeding.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An irrigation device for forest tree breeding includes a drone body with an arm mounted on it and wings mounted at the ends of the arm. An irrigation mechanism is provided on the drone body, comprising an installation chamber containing a liquid tank. Multiple ribs are arranged on the inner side of the bottom of the liquid tank, dividing the bottom into multiple liquid channels. Multiple main liquid bladders are installed on the top of the ribs, each corresponding to a liquid channel, and the main liquid bladders and channels cooperate to form a liquid cavity for containing liquid. A nozzle is connected to the bottom of each liquid channel via a connecting component, and the nozzle is fixed to the arm by a nozzle bracket. A squeezing component is provided above each main liquid bladder to press out the liquid from the main liquid bladder and discharge it through the nozzle.

[0007] As a preferred embodiment of the present invention: the connecting component includes a liquid delivery pipe, one end of which is connected to the bottom of the liquid tank, and the other end of which is connected to an elastic liquid bladder. One side of the elastic liquid bladder is connected to a liquid distribution pipe, one end of which is connected to the nozzle, and a control valve for controlling the opening and closing of the liquid distribution pipe is provided on the liquid distribution pipe.

[0008] As a preferred embodiment of the present invention: a liquid bladder box is installed on the arm, the bottom of the elastic liquid bladder is fixed to the inner wall of the bottom of the liquid bladder box, and a distance measuring sensor is installed on the inner wall of the top of the liquid bladder box. The distance measuring sensor and the control valve are connected to the same control system.

[0009] As a preferred embodiment of the present invention: the extrusion assembly includes a pressure plate, a side groove is provided on the side of the liquid tank, a threaded seat is fixed on the outside of the pressure plate, the threaded seat slides in the side groove, a screw motor is installed in the installation chamber, a screw is installed at the output end of the screw motor, and the screw is threadedly connected to the threaded seat.

[0010] As a preferred embodiment of the present invention, the outer side of the main liquid bladder has a Z-shaped continuous pleated structure, and each pleat is equipped with a support rib adapted to the shape of the main liquid bladder.

[0011] As a preferred embodiment of the present invention: the pressure plate is connected to a side bracket, a guide frame is fixed in the installation room, and the side bracket slides on the outer wall of the guide frame.

[0012] As a preferred embodiment of the present invention: a central seat is installed at the center of the bottom of the liquid tank, and a second leak is provided on the outer side of the central seat. The central seat is connected to the corresponding liquid tank through each second leak. The inner diameter of the bottom end of the central seat gradually converges. A sealing plug is installed inside the central seat that can slide up and down. The shape of the bottom end of the sealing plug matches the inner shape of the bottom end of the central seat. The sealing plug is hollow inside and has an opening at the bottom. A first leak is provided on the side of the sealing plug that matches the position of the second leak. The opening is connected to each first leak through the inside of the sealing plug. A sealing seat is installed on the top of the sealing plug. The top of the sealing seat and the inner wall of the top of the central seat are connected by a spring. Based on the spring force, the sealing plug is pressed against the bottom of the central seat, and at the same time, the sealing seat seals each second leak. A liquid supply assembly is connected to the bottom of the liquid tank. The liquid supply end of the liquid supply assembly is connected to the bottom end of the central seat. When the liquid supply assembly supplies liquid, the water pressure pushes the sealing plug upward, causing the first leak to rise to the position of the second leak, thereby connecting the sealing plug and the liquid tank and realizing the supply of liquid to each liquid tank.

[0013] As a preferred embodiment of the present invention: a central rod is installed on the top of the central seat, and a sliding block is fixed in the middle of the pressure plate, the sliding block being slidably connected to the outer wall of the central rod.

[0014] As a preferred embodiment of the present invention: the liquid supply assembly includes a liquid pump, a mounting frame is installed at the bottom of the liquid tank, the liquid pump is mounted on the mounting frame, a take-up and untake-up roller is rotatably mounted on the mounting frame, a take-up and untake-up motor for driving the take-up and untake-up roller is installed on one side of the mounting frame, one end of the liquid pump is connected to a center seat through a short pipe, and the other end of the liquid pump is connected to a suction pipe, the middle part of the suction pipe is fixed to the take-up and untake-up roller by a fixing buckle, and one end of the suction pipe hangs down; in the winding state, the suction pipe is not completely tightened on the take-up and untake-up roller.

[0015] As a preferred embodiment of the present invention: a suction head is installed at the end of the suction tube, an end cover is detachably installed on the outside of the end of the suction tube, a first filter hole is provided on the end cover, and a second filter hole is provided on the suction head.

[0016] The beneficial effects of this invention are as follows: 1. By setting up multiple partitioned main liquid bladders and liquid tanks, the present invention can work based on the extrusion component to uniformly compress the main liquid bladder downwards, so that the liquid is discharged from the nozzle, thereby better controlling the consistent liquid volume of each nozzle and avoiding uneven liquid spraying caused by slight blockage or other factors in a certain nozzle.

[0017] 2. By incorporating a distance sensor and other structures, this invention enables liquid to first fill the elastic liquid bladder when the main liquid bladder is squeezed. The elastic liquid bladder expands towards the distance sensor after being filled with liquid. Once the squeezing is complete, the control valve is activated, allowing the elastic liquid bladder to squeeze the liquid out of the nozzle based on its rebound force. When the change in the distance sensor value reaches a threshold, the control valve is closed, thus achieving the purpose of quantitative irrigation.

[0018] 3. By setting support ribs and distributing them in multiple layers along a Z-shaped continuous fold, the present invention can maintain the shape of the main liquid bladder without affecting its compression.

[0019] 4. By setting up a liquid supply component, the present invention can simultaneously supply liquid to each liquid chamber during liquid supply, thereby improving the liquid supply efficiency. When not supplying liquid, the sealing of the plug seat keeps each liquid chamber independent, so as to facilitate uniform irrigation.

[0020] 5. By setting up a liquid supply component, the present invention can control the rotation of the take-up and unwinding rollers during unwinding, so that the liquid suction tube is completely tightened on the take-up and unwinding rollers on the other side, without causing jamming. The middle part of the liquid suction tube is fixed to the take-up and unwinding rollers by a fixing buckle, thus avoiding the liquid suction tube from tightening itself by gravity in the standby state. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an irrigation device for forest tree breeding proposed in this invention; Figure 2 This is a schematic diagram of the irrigation device for forest tree breeding proposed in this invention from another angle; Figure 3 This is a cross-sectional schematic diagram of the elastic liquid bladder of an irrigation device for forest tree breeding proposed in this invention; Figure 4 This is a cross-sectional structural schematic diagram of the installation chamber of an irrigation device for forest tree breeding proposed in this invention; Figure 5 This is a cross-sectional structural schematic diagram of the liquid tank and main liquid bladder of an irrigation device for forest tree breeding proposed in this invention. Figure 6 This is a cross-sectional view of the disassembled structure of the liquid tank and main liquid bladder of an irrigation device for forest tree breeding proposed in this invention. Figure 7 This is a schematic diagram of the structure of the central seat and sealing block of an irrigation device for forest tree breeding proposed in this invention, after cross-sectional view.

[0022] In the diagram: 1-UAV body; 2-Arm; 3-Liquid bladder box; 4-Wing; 5-Suction pipe; 6-Take-up / unwind motor; 7-Liquid tank; 8-Liquid delivery pipe; 9-Control valve; 10-End cover; 11-Take-up / unwind roller; 12-Range sensor; 13-Elastic liquid bladder; 14-Liquid distribution pipe; 15-Nozzle; 16-Nozzle bracket; 17-Installation chamber; 18-Liquid pump; 19-Suction head; 20-Installation frame; 21-Screw; 22-Screw motor; 23-Guide frame; 24-Side bracket; 25-Slide seat; 26-Center rod; 27-Pressure plate; 28-Support rib; 29-Main liquid bladder; 30-Liquid tank; 31-Rib plate; 32-Center seat; 33-Spring; 34-First leak; 35-Sealing plug; 36-Sealing seat; 37-Second leak. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0024] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0025] Example 1: An irrigation device for forest tree breeding, such as Figure 1-7As shown, the device includes a drone body 1, on which an arm 2 is mounted, and at the end of the arm 2 are wings 4. An irrigation mechanism is provided on the drone body 1, comprising an installation chamber 17, within which a liquid tank 7 is installed. Multiple ribs 31 are provided on the inner bottom side of the liquid tank 7, dividing the bottom of the liquid tank 7 into multiple liquid troughs 30. Multiple main liquid bladders 29 are mounted on the top of the ribs 31, with each main liquid bladder 29 corresponding to a liquid trough 30, and the main liquid bladders 29 and liquid troughs 30 working together to form a liquid cavity for containing liquid. A nozzle 15 is connected to the bottom of each liquid trough 30 via a connecting component, and the nozzle 15 is fixed to the arm 2 via a nozzle bracket 16. A squeezing component is provided above each main liquid bladder 29 to squeeze out the liquid from the main liquid bladder 29 and discharge it through the nozzle 15. By setting multiple partitions for the main liquid bladder 29 to cooperate with the liquid tank 30, the main liquid bladder 29 can be pressed downwards and evenly based on the operation of the extrusion component, so that the liquid is discharged from the nozzle 15, which better controls the consistent liquid volume of each nozzle 15 and avoids uneven liquid spraying caused by slight blockage or other factors in a certain nozzle 15.

[0026] To facilitate spraying; such as Figure 3 As shown, the connecting component includes a liquid delivery pipe 8, one end of which is connected to the bottom of the liquid tank 7, and the other end of which is connected to an elastic liquid bladder 13. One side of the elastic liquid bladder 13 is connected to a liquid distribution pipe 14, one end of which is connected to the nozzle 15. A control valve 9 is provided on the liquid distribution pipe 14 to control the opening and closing of the liquid distribution pipe 14.

[0027] To facilitate liquid spraying; such as Figure 3 As shown, a liquid bladder box 3 is installed on the arm 2, the bottom of the elastic liquid bladder 13 is fixed to the inner wall of the bottom of the liquid bladder box 3, and a distance sensor 12 is installed on the inner wall of the top of the liquid bladder box 3. The distance sensor 12 and the control valve 9 are connected to the same control system. By setting up structures such as the distance sensor 12, when the main liquid bladder 29 is squeezed, the liquid can first fill the elastic liquid bladder 13. The elastic liquid bladder 13 expands towards the distance sensor 12 after being filled with liquid. After the squeezing is completed, the control valve 9 is opened, so that the elastic liquid bladder 13 squeezes the liquid out of the nozzle 15 based on the rebound force. After the change in the value of the distance sensor 12 reaches the threshold, the control valve 9 is closed, thus achieving the purpose of quantitative irrigation. The height of the elastic fluid bladder 13 should be higher than the height of the main fluid bladder 29.

[0028] To facilitate extrusion; such as Figure 4 , Figure 5 , Figure 6As shown, the extrusion assembly includes a pressure plate 27, a side groove is provided on the side of the liquid tank 7, a threaded seat is fixed on the outside of the pressure plate 27, the threaded seat slides in the side groove, a screw motor 22 is installed in the installation chamber 17, a screw 21 is installed at the output end of the screw motor 22, and the screw 21 is threadedly connected to the threaded seat.

[0029] To improve structural strength; such as Figure 5 , Figure 6 As shown, the outer side of the main liquid bladder 29 has a Z-shaped continuous pleated structure, and each pleat is equipped with a support rib 28 that matches the shape of the main liquid bladder 29. The width of the support rib 28 is much smaller than the spacing between each pleat. By setting support ribs 28 and distributing them in multiple layers along a continuous Z-shaped fold, the shape of the main liquid bladder 29 can be maintained without affecting its compression.

[0030] To improve structural stability; such as Figure 5 As shown, the pressure plate 27 is connected to a side bracket 24, and a guide frame 23 is fixed inside the installation chamber 17. The side bracket 24 slides on the outer wall of the guide frame 23. The screw motor 22 operates, driving the screw 21 to rotate, which in turn drives the pressure plate 27 to compress or reset the main liquid bladder 29 under the guidance of the guide frame 23.

[0031] To facilitate the simultaneous replenishment of liquid into each liquid chamber; such as Figure 5 , Figure 6 , Figure 7 As shown, a center seat 32 is installed at the center of the bottom of the liquid tank 7. A second leak 37 is provided on the outer side of the center seat 32. The center seat 32 is connected to the corresponding liquid tank 30 through each second leak 37. The inner diameter of the bottom end of the center seat 32 gradually converges. A sealing plug 35 is installed inside the center seat 32 and can slide up and down. The shape of the bottom end of the sealing plug 35 is adapted to the inner shape of the bottom end of the center seat 32. The sealing plug 35 is hollow inside and has an opening at the bottom. A first leak 34 is provided on the side of the sealing plug 35, which is adapted to the position of the second leak 37. The opening is connected to each first leak 34 through the inside of the sealing plug 35. A sealing seat 36 is installed on the top of the sealing plug 35. The top of the sealing seat 36 and the inner wall of the top of the center seat 32 are connected by a spring 33. Based on the force of the spring 33, the sealing plug 35 is pressed against the bottom of the center seat 32, and at the same time, the sealing seat 36 seals each of the second leaks 37. A liquid supply assembly is connected to the bottom of the liquid tank 7. The liquid supply end of the liquid supply assembly is connected to the bottom end of the center seat 32. When the liquid supply assembly supplies liquid, it pushes the sealing plug 35 upward based on the water pressure, so that the first leak 34 rises to the position of the second leak 37, thereby connecting the sealing plug 35 and the liquid tank 30, and realizing the supply of liquid to each liquid tank 30. By setting up a liquid supply component, liquid can be supplied to each liquid chamber simultaneously during liquid supply, improving the liquid supply efficiency. When not supplying liquid, the sealing seat 36 seals each liquid chamber independently, so as to facilitate uniform irrigation.

[0032] To improve the stability of the movement of the pressure plate 27; such as Figure 5 , Figure 6 As shown, a central rod 26 is installed on the top of the central seat 32, and a slide 25 is fixed in the middle of the pressure plate 27. The slide 25 is slidably connected to the outer wall of the central rod 26.

[0033] To facilitate fluid replenishment; such as Figure 4 , Figure 5 As shown, the liquid supply assembly includes a liquid pump 18, a mounting frame 20 is installed at the bottom of the liquid tank 7, the liquid pump 18 is mounted on the mounting frame 20, a take-up and untake-up roller 11 is rotatably mounted on the mounting frame 20, a take-up and untake-up motor 6 for driving the take-up and untake-up roller 11 is installed on one side of the mounting frame 20, one end of the liquid pump 18 is connected to the center seat 32 through a short pipe, and the other end of the liquid pump 18 is connected to a suction pipe 5. The middle part of the suction pipe 5 is fixed to the take-up and untake-up roller 11 by a fixing buckle, and one end of the suction pipe 5 hangs down; in the winding state, the suction pipe 5 is not completely tightened on the take-up and untake-up roller 11; By setting up a liquid supply component, during unwinding, the rotation of the take-up and unwinding rollers 11 can be controlled so that the liquid suction pipe 5 is below, and since the other side is completely tightened on the take-up and unwinding rollers 11, it will not cause jamming. The middle part of the liquid suction pipe 5 is fixed to the take-up and unwinding rollers 11 by a fixing buckle, which avoids the liquid suction pipe 5 from tightening itself by gravity in the standby state.

[0034] To avoid the inhalation of impurities; such as Figure 4 As shown, a suction head 19 is installed at the end of the suction tube 5, and an end cover 10 is detachably installed on the outside of the end of the suction tube 5. The end cover 10 is provided with a first filter hole, and the suction head 19 is provided with a second filter hole.

[0035] For aspects not fully disclosed in this invention, such as specific control methods, signal transmission methods, power supply methods, etc., since they are conventional existing technologies and common knowledge, they are not described in detail. The above specific embodiments are merely exemplary embodiments of this invention, and some structures of this invention can be equivalently replaced with structures commonly used in the prior art to achieve the same or similar technical effects.

[0036] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An irrigation device for forest tree breeding, characterized in that, The device includes a drone body (1), on which an arm (2) is mounted, and an wing (4) is mounted at the end of the arm (2). The drone body (1) is equipped with an irrigation mechanism, which includes an installation chamber (17). A liquid tank (7) is installed in the installation chamber (17). Multiple ribs (31) are provided on the inner side of the bottom of the liquid tank (7). The ribs (31) divide the bottom of the liquid tank (7) into multiple liquid troughs (30). Multiple main liquid bladders (29) are installed on the top of the ribs (31). The main liquid bladders (29) and the liquid troughs (30) correspond one-to-one, and the main liquid bladders (29) and the liquid troughs (30) cooperate to form a liquid cavity for containing liquid. The bottom of the liquid trough (30) is connected to a nozzle (15) through a connecting component. The nozzle (15) is fixed to the arm (2) through a nozzle bracket (16). A squeezing component is provided above the main liquid bladders (29) to squeeze out the liquid from the main liquid bladders (29) and discharge it through the nozzle (15).

2. The irrigation device for forest tree breeding according to claim 1, characterized in that, The connecting component includes a liquid delivery pipe (8), one end of which is connected to the bottom of the liquid tank (7), and the other end of which is connected to an elastic liquid bladder (13). One side of the elastic liquid bladder (13) is connected to a liquid distribution pipe (14), one end of which is connected to a nozzle (15). A control valve (9) is provided on the liquid distribution pipe (14) to control the opening and closing of the liquid distribution pipe (14).

3. The irrigation device for forest tree breeding according to claim 2, characterized in that, The arm (2) is equipped with a liquid bladder box (3), the bottom of the elastic liquid bladder (13) is fixed to the bottom inner wall of the liquid bladder box (3), and a distance sensor (12) is installed on the top inner wall of the liquid bladder box (3). The distance sensor (12) and the control valve (9) are connected to the same control system.

4. The irrigation device for forest tree breeding according to claim 1, characterized in that, The extrusion assembly includes a pressure plate (27), a side groove is provided on the side of the liquid tank (7), a threaded seat is fixed on the outside of the pressure plate (27), the threaded seat slides in the side groove, a screw motor (22) is installed in the installation chamber (17), a screw (21) is installed at the output end of the screw motor (22), and the screw (21) is connected to the threaded seat by a thread.

5. The irrigation device for forest tree breeding according to claim 4, characterized in that, The outer side of the main liquid bladder (29) has a Z-shaped continuous pleated structure, and each pleat is equipped with a support rib (28) that matches the shape of the main liquid bladder (29).

6. The irrigation device for forest tree breeding according to claim 4, characterized in that, The pressure plate (27) is connected to a side bracket (24), and a guide frame (23) is fixed inside the installation chamber (17). The side bracket (24) slides on the outer wall of the guide frame (23).

7. The irrigation device for forest tree breeding according to claim 4, characterized in that, A center seat (32) is installed at the center of the bottom of the liquid tank (7). A second leak (37) is provided on the outer side of the center seat (32). The center seat (32) is connected to the corresponding liquid tank (30) through each second leak (37). The inner diameter of the bottom end of the center seat (32) gradually converges. A sealing plug (35) is installed inside the center seat (32) and can slide up and down. The shape of the bottom end of the sealing plug (35) is adapted to the inner shape of the bottom end of the center seat (32). The sealing plug (35) is hollow inside and has an opening at the bottom. A first leak (34) is provided on the side of the sealing plug (35) and is adapted to the position of the second leak (37). The opening is connected to each first leak (34) through the inside of the sealing plug (35). A sealing seat (36) is installed on the top of the plug (35). The top of the sealing seat (36) and the inner wall of the top of the center seat (32) are connected by a spring (33). Based on the force of the spring (33), the sealing plug (35) is pressed against the bottom of the center seat (32), and the sealing seat (36) seals each second leak (37). The bottom of the liquid tank (7) is connected to a liquid supply assembly. The liquid supply end of the liquid supply assembly is connected to the bottom end of the center seat (32). When the liquid supply assembly supplies liquid, it pushes the sealing plug (35) upward based on the water pressure, so that the first leak (34) rises to the position of the second leak (37), thereby connecting the sealing plug (35) and the liquid tank (30) to achieve liquid supply to each liquid tank (30).

8. The irrigation device for forest tree breeding according to claim 7, characterized in that, A central rod (26) is installed on the top of the central seat (32), and a slide (25) is fixed in the middle of the pressure plate (27). The slide (25) is slidably connected to the outer wall of the central rod (26).

9. An irrigation device for forest tree breeding according to claim 7, characterized in that, The liquid supply assembly includes a liquid pump (18), a mounting frame (20) is installed at the bottom of the liquid tank (7), the liquid pump (18) is installed on the mounting frame (20), a take-up and untake-up roller (11) is rotatably installed on the mounting frame (20), a take-up and untake-up motor (6) for driving the take-up and untake-up roller (11) is installed on one side of the mounting frame (20), one end of the liquid pump (18) is connected to the center seat (32) through a short pipe, and the other end of the liquid pump (18) is connected to the suction pipe (5). The middle part of the suction pipe (5) is fixed to the take-up and untake-up roller (11) by a fixing buckle, and one end of the suction pipe (5) hangs down; in the winding state, the suction pipe (5) is not completely tightened on the take-up and untake-up roller (11).

10. An irrigation device for forest tree breeding according to claim 9, characterized in that, The suction tube (5) is equipped with a suction head (19) at the end, and an end cover (10) is detachably installed on the outside of the end of the suction tube (5). The end cover (10) is provided with a first filter hole, and the suction head (19) is provided with a second filter hole.

Images