A UAV flame retardant spraying system

Abstract

The present invention provides a flame retardant spraying system for unmanned aerial vehicles, which belongs to unmanned aerial vehicles and includes an unmanned aerial vehicle body, a mounting frame is arranged at the bottom of the unmanned aerial vehicle body, a telescopic tube assembly is arranged on the mounting frame, a flame retardant spraying system is arranged at the movable end of the telescopic tube assembly, and a first driving assembly for driving the telescopic tube assembly to extend and retract in length is arranged on the unmanned aerial vehicle body; the flame retardant spraying system includes a solvent tank for containing flame retardant, a spraying port is arranged at the bottom of the solvent tank, an electronic valve for opening and closing the spraying port is arranged on the solvent tank, and a booster assembly is arranged on the mounting frame. When the unmanned aerial vehicle sprays flame retardant on a forest farm, the unmanned aerial vehicle flies to a safe flight altitude slightly above the forest, and the telescopic tube assembly is extended to lower the solvent tank to the forest, and the air flow is blocked by the surrounding forests, etc., to reduce the air flow rate, reduce the situation of the flame retardant being blown away after spraying, and improve the effective spraying rate of the flame retardant.

Description

Technical Field

[0001] The invention relates to the technical field of unmanned aerial vehicles, and in particular to a flame retardant spraying system for unmanned aerial vehicles. Background Art

[0002] With the development of science and technology in recent years, drone technology has been widely used and developed in many fields of life. Fire rescue has always been an urgent and dangerous task. Traditional ground firefighting requires firefighters to face the fire scene as soon as possible, which has a high risk factor. Especially for forest fire fighting, it takes a lot of manpower to transport firefighting facilities to the scene, and the firefighting efficiency is low. Therefore, as a supplement to ground firefighting, drone firefighting can quickly reach the fire fighting point from high altitude and carry out a series of firefighting work, which reduces the biggest danger hidden danger in the early stage for the subsequent firefighters to enter the scene, and has become an important development direction of consumer firefighting.

[0003] The patent with the announcement number CN112915421B discloses a method and a drone for spraying flame retardants for forest fires based on drones, including the following steps: using an infrared temperature measurement component to detect the fire area, allowing the GPS positioning component to obtain the first position information of the fire area, and sending the first position information to the remote control console; obtaining the first wind direction information of the fire area through a wind direction sensor, and sending the first wind direction information to the remote control console; determining the spraying area of ​​the flame retardant, the spraying area is the area around the fire area that has not caught fire; controlling the flame retardant spraying component to spray the flame retardant to the spraying area through the remote control console to form a flame retardant isolation zone. Among them, the flame retardant spraying component includes a flame retardant storage box, a flame retardant outlet and an electric control valve; the flame retardant storage box is provided with a flame retardant outlet, and the flame retardant outlet is connected to the electric control valve. After the electric control valve is opened to connect the flame retardant outlet with the external space of the flame retardant storage box, the flame retardant can fall to the spraying area under the action of gravity.

[0004] However, when drones are spraying flame retardants over forest farms, they need to spray at high altitudes to avoid scratching themselves against treetops on the ground. The air at high altitudes is affected by the temperature of the fire and the airflow rate is fast. The flame retardant is easily affected by the airflow during its fall and flies everywhere, which reduces the effective utilization rate of the flame retardant. Summary of the invention

[0005] In view of the above problems in the prior art, the present invention provides a flame retardant spraying system for an unmanned aerial vehicle.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0007] Provided is a UAV flame retardant spraying system, characterized in that it comprises a UAV body, a mounting frame is provided at the bottom of the UAV body, a telescopic tube assembly is provided on the mounting frame, a flame retardant spraying system is provided at the movable end of the telescopic tube assembly, and a first driving assembly for driving the telescopic tube assembly to extend and retract its length is provided on the UAV body;

[0008] The flame retardant spraying system comprises a solvent tank for containing flame retardant, a spraying port is arranged at the bottom of the solvent tank, an electronic valve for opening and closing the spraying port is arranged on the solvent tank, and a booster assembly is arranged on the mounting frame.

[0009] Furthermore, the telescopic tube assembly comprises a plurality of telescopic branch tubes coaxially slidably sleeved, the top of the telescopic branch tube is provided with an anti-detachment hook portion folded outward twice, the bottom of the telescopic branch tube is provided with an anti-detachment overlap portion folded inward twice, a sealing ring is provided between the anti-detachment hook portion and the anti-detachment overlap portion, the top end of the outermost telescopic branch tube is connected to the mounting frame, and the bottom end of the innermost telescopic branch tube is detachably connected to the solvent tank;

[0010] The first driving assembly includes a driving motor, a winding drum, a storage wire and a pulley. The pulley is rotatably arranged at the bottom end of the innermost telescopic branch pipe. The winding drum is rotatably arranged on the mounting frame and is located on one side of the telescopic tube assembly. The driving motor is used to drive the winding drum to rotate. The storage wire is wound on the winding drum. One end of the storage wire is fixedly connected to the winding wire, and the other end is fixedly connected to the mounting frame after passing around the pulley.

[0011] Furthermore, the boosting assembly includes a compressed gas cylinder and a first connecting head. A sealing cover for closing the top of the telescopic branch tube is provided at the top of the outermost telescopic branch tube. A sealed air cavity is formed between the sealing cover and the telescopic tube assembly. The first connecting head is provided on the sealing cover and is connected to the air cavity. The compressed gas cylinder is connected to the first connecting head. An electronic exhaust valve for exhaust is provided on the sealing cover.

[0012] Furthermore, the solvent tank includes a tank body, a solvent soft bag and a push plate. The tank body is detachably arranged at the bottom end of the innermost telescopic branch pipe. The top of the tank body is open. The solvent soft bag is arranged in the tank body. The solvent soft bag is provided with a liquid outlet. The liquid outlet is detachably connected to the spraying port at the bottom of the tank body. The push plate is coaxially slidably arranged in the tank body above the solvent soft bag. The top opening of the tank body is connected to the air cavity in the telescopic tube assembly.

[0013] Furthermore, an electronic safety valve is arranged on the sealing cover.

[0014] Furthermore, a slide rail is provided in the tank body, and the push plate is coaxially slidably connected in the tank body. A first limit assembly for limiting the movement of the push plate is provided in the tank body, and the first limit assembly includes a limit part and an electric push rod. The limit part is arranged on the side of the push plate away from the solvent soft bag, and the limit part includes a limit block and a connecting rod. One end of the connecting rod is coaxially hinged with the push plate, and the other end is fixedly connected to the limit block. The limit block extends out of the push plate and can rotate coaxially relative to the push plate. A slide groove adapted to the limit block is provided on the inner wall of the tank body, and a limit groove for the limit block to be engaged is provided at one end of the slide groove close to the drone body. The electric push rod is arranged on the push plate, and the output end of the electric push rod is hinged to the connecting rod.

[0015] Furthermore, a guide tube is coaxially arranged on the outer side of the outermost telescopic branch tube, and both ends of the guide tube are open. The end of the guide tube away from the UAV body is the smaller end of the guide tube, and a guide channel is formed between the guide tube and the telescopic branch tube.

[0016] The UAV body is provided with a flight power system, and the top opening of the guide tube is located below the flight power system.

[0017] Furthermore, the mounting frame is rotatably connected relative to the UAV body, and a second limit assembly for limiting the rotation of the mounting frame is provided on the UAV body;

[0018] The second limiting component includes a limiting pin. Two mounting plates parallel to each other are arranged on both sides of the mounting frame on the UAV body. A rotating shaft is arranged on the mounting frame. The mounting frame is rotatably connected to the mounting plate through the rotating shaft. A first pin hole group is opened on the mounting frame. At least two second pin hole groups are opened on the mounting plate along the circumferential direction of the rotating shaft. The limiting pin passes through the first pin hole group and the second pin hole group at the same time to limit the rotation of the mounting frame.

[0019] Furthermore, the guide tube includes a fixed ring, a movable ring and a telescopic sleeve. The fixed ring and the movable ring are connected through the telescopic sleeve. The fixed ring is fixedly connected to the UAV body, and the movable ring is fixedly connected to the outermost telescopic branch pipe.

[0020] The beneficial effects of the present invention are as follows: 1. After the UAV body flies to the minimum safe flight altitude above the treetops of the forest farm, the spraying height of the solvent tank can be lowered by extending the telescopic tube assembly, and the high-altitude air flow is blocked by the woods, etc. When the solvent tank sprays the flame retardant, the flame retardant is less blown by the wind, which can effectively reduce the influence of air on the spraying of the flame retardant and improve the effective spraying rate of the flame retardant;

[0021] 2. The booster component can increase the spraying rate of the flame retardant, thereby effectively reducing the situation where the flame retardant is blown away during the spraying process and improving the effective spraying rate of the flame retardant;

[0022] 3. By changing the rotation angle of the telescopic tube assembly, the drone can spray flame retardants on the facades of high-rise buildings in the city, which is suitable for rescue operations in various scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the downward spraying operation of the drone in an embodiment of the present application.

[0024] Figure 2 This is a schematic diagram of the state of a drone spraying the facade of a high-rise building in an embodiment of the present application.

[0025] Figure 3 This is a schematic diagram of the partial structure of the UAV in the cross-sectional state of the guide tube in an embodiment of the present application.

[0026] Figure 4 It is a schematic cross-sectional structural diagram of the telescopic tube structure of an embodiment of the present application.

[0027] Figure 5 This is a partial European structural schematic diagram of the solvent tank according to an embodiment of the present application.

[0028] Among them, 1. UAV body; 11. Mounting frame; 12. Mounting plate; 13. Limit pin; 2. Telescopic tube assembly; 21. Telescopic branch pipe; 22. Anti-detachment hook; 23. Anti-detachment overlap; 24. Sealing cover; 25. Electronic exhaust valve; 26. Air cavity; 27. Electronic safety valve; 3. Solvent tank; 31. Spray port; 32. Electronic valve; 33. Tank body; 34. Solvent soft bag; 35. Push plate; 36. Electric push rod; 37. Connecting rod; 38. Limit block; 381. Slide groove; 382. Limit groove; 41. Drive motor; 42. Winding reel; 43. Storage wire; 44. Pulley; 51. Compressed gas cylinder; 6. Guide tube; 61. Fixed ring; 62. Movable ring; 63. Telescopic sleeve. DETAILED DESCRIPTION

[0029] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0030] The embodiment of the present invention provides a flame retardant spraying system for an unmanned aerial vehicle, referring to Figure 1 and Figure 2, including a drone body 1, on which a control system, a flight power system, a video acquisition system, a wireless communication system and a power supply system are arranged. The control system is electrically connected to the executive components in each system and is used to control the actions of the executive components. The video acquisition system can take pictures of the environment around the drone body 1 and transmit them to the operator's remote communication terminal through the wireless communication system. The flight power system can enable the drone body 1 to perform actions such as flying, hovering and turning. The power supply system supplies power to the executive components in each system on the drone body 1.

[0031] Reference Figure 3 A mounting frame 11 is provided at the bottom of the UAV body 1, a telescopic tube assembly 2 is connected to the mounting frame 11, a flame retardant spraying system is connected to the movable end of the telescopic tube assembly 2, and a first driving assembly for driving the telescopic tube assembly 2 to extend and retract is provided on the UAV body 1. The flame retardant spraying system includes a solvent tank 3 for containing flame retardant, a spraying port 31 is provided at the bottom of the tube, an electronic valve 32 for opening and closing the spraying port 31 is provided on the solvent tank 3, and a pressurizing assembly for pressurizing the solvent tube is provided on the mounting frame 11.

[0032] During the flight of the drone body performing the flame retardant spraying, the drone body 1 flies and descends to a lower safe flight altitude, and the first drive component drives the telescopic tube component 2 to extend the length, so that the solvent tank 3 is closer to the ground, and then the electronic valve 32 is used to open the spray port 31, so that the flame retardant can be sprayed below the drone, which reduces the spraying height of the flame retardant, concentrates the spraying of the flame retardant, and reduces the amount of flame retardant wasted by the wind. And through the booster component, the sprayed flame retardant can be pressurized, the spraying rate of the flame retardant can be increased, and the anti-interference behavior can be reduced to reduce the waste of flame retardant.

[0033] Reference Figure 4 Specifically, the telescopic tube assembly 2 includes a plurality of coaxially slidably sleeved telescopic branch tubes 21, a coaxial anti-dropout hook portion 22 folded twice outward of the telescopic branch tube 21 is provided at the top of the telescopic branch tube 21, and an anti-dropout overlap portion 23 coaxially folded twice inward of the telescopic branch tube 21 is provided at the bottom of the telescopic branch tube. A sealing ring is provided between the anti-dropout hook portion 22 and the anti-dropout overlap portion 23. After the telescopic tube assembly 2 is extended, the anti-dropout hook portion 22 and the anti-dropout overlap portion 23 can cooperate with each other, and the sealing of the telescopic tube connection is maintained by the sealing ring. The top of the telescopic branch tube 21 located at the outermost layer is connected to the mounting bracket, and the bottom end of the innermost telescopic branch tube 21 is detachably connected to the solvent tank 3. After the flame retardant in the solvent tank 3 is emptied, the drone body 1 lands to the take-off point, and the emptied solvent tank 3 can be quickly disassembled and replaced with a new solvent tank 3, and the drone body 1 can take off again and continue to work.

[0034] Reference Figure 5In the embodiment of the present application, both ends of each telescopic branch tube 21 are open, and the first driving assembly includes a driving motor 41, a winding drum 42, a storage wire 43 and a pulley 44. The pulley 44 is rotatably mounted on the outer wall of the innermost telescopic branch tube 21 and is located at the bottom end of the telescopic branch tube 21. The winding drum 42 is rotatably mounted on the mounting frame 11 and is located on one side of the telescopic tube assembly 2. The driving motor 41 is fixed on the mounting frame 11 and is used to drive the winding drum 42 to rotate. The storage wire 43 is wound on the winding drum 42. One end of the storage wire 43 is fixedly connected to the winding drum 42, and the other end is fixedly connected to the mounting frame 11 after passing through the pulley 44. When the driving motor 41 drives the winding drum 42 to keep tightening the storage line 43, the telescopic tube assembly 2 is blocked by the storage line 43 and remains in the storage state. After the drone body 1 takes off, the driving motor 41 relaxes the driving force, the winding drum 42 rotates, and the storage line 43 is lengthened. Under the action of gravity, the solvent tank 3 drives the telescopic tube assembly 2 to lengthen.

[0035] In the embodiment of the present application, the booster assembly includes a compressed gas cylinder 51 and a first connector. The top of the outermost telescopic branch tube 21 is provided with a sealing cover 24 for closing the top of the telescopic branch tube. The solvent tank 3 closes the bottom end of the innermost telescopic branch tube 21, and a sealed air cavity 26 is formed between the sealing cover 24 and the solvent tube in the telescopic branch tube 21 group. The first connector is mounted on the sealing cover 24, and the first connector is connected to the air cavity 26. The compressed gas cylinder 51 is detachably mounted on the drone body 1, and the gas outlet end of the compressed gas cylinder 51 is detachably connected to the first connector. The sealing cover 24 is provided with an electronic exhaust valve 25 for exhaust. Through the setting of the booster assembly, when the telescopic tube assembly 2 is in the shortened state, the electronic exhaust valve 25 is closed, and the air cavity 26 remains sealed, so that the shortened state of the telescopic tube assembly 2 can be maintained.

[0036] The gas outlet of the compressed gas cylinder 51 adopts an electronic valve 32. After the control system controls the electronic valve 32 to open slightly, the gas enters the air cavity 26, so that the telescopic tube assembly 2 is extended. When the telescopic tube assembly 2 needs to be shortened, the control system controls the electronic valve 32 on the compressed gas cylinder 51 to close, the electronic exhaust valve 25 to open, and the drive motor 41 drives the winding drum 42 to reel in the storage line 43, so that the telescopic tube assembly 2 can be shortened. When the telescopic tube assembly 2 is shortened, the drive motor 41 does not need to maintain the driving force at all times, thereby improving the working stability of the drive assembly. In the embodiment of the present application, the output shaft of the drive motor 41 can rotate freely after power failure, and a guide ring can be set on the outside of the pulley 44 on the telescopic tube assembly 2 so that the storage rope can remain aligned with the pulley 44.

[0037] In the embodiment of the present application, the solvent tank 3 includes a tank body 33, a solvent soft bag 34 and a push plate 35. The tank body 33 is detachably mounted on the bottom end of the innermost telescopic branch pipe 21. Specifically, the tank body 33 is threadedly connected to the bottom end of the innermost telescopic branch pipe 21. The top of the tank body 33 is open and communicates with the air cavity 26 in the telescopic tube assembly 2. The solvent soft bag 34 is mounted in the tank body 33. The solvent soft bag 34 is provided with a liquid outlet, which is threadedly detachably connected to the spray port 31 at the bottom of the tank body 33. The push plate 35 is coaxially slidably arranged in the tank body 33, and the push plate 35 is located on the side of the solvent soft bag 34 away from the spraying port 31. When the booster assembly inflates the air cavity 26 to extend the telescopic tube assembly 2, the booster assembly continues to inflate the air cavity 26 and opens the electronic valve 32 on the spraying port 31 at the bottom of the solvent tank 3. The air pressure can be used to push the push plate 35, squeeze the solvent soft bag 34, and spray the flame retardant from the spraying port 31, thereby increasing the flame retardant injection power, effectively reducing the situation where the flame retardant is blown away by the wind, and improving the effective utilization rate of the flame retardant.

[0038] Furthermore, the sealing cover 24 is provided with an electronic safety valve 27, through which the air pressure in the air cavity 26 can be kept within a safe air pressure value range during and after the flame retardant is sprayed. And by adjusting the pressure limit value of the electronic safety valve 27 through the control system, the maximum pressure value in the air cavity 26 can be adjusted, that is, the maximum spraying rate of the flame retardant can be adjusted.

[0039] In the embodiment of the present application, a slide rail is provided in the tank body 33 along its axial direction, a slider is fixedly connected to the push plate 35, and the push plate 35 is slidably connected to the slide rail via the slider. A first limiting assembly for limiting the movement of the push plate 35 is also provided in the tank body 33. The first limiting assembly can be a limiting part and an electric push rod 36. The limiting part includes a limiting block 38 and a connecting rod 37. The limiting part is arranged on the side of the push plate 35 away from the solvent soft bag 34. One end of the connecting rod 37 is coaxially hinged with the push plate 35, and the other end is fixedly connected to the limiting block 38. The limiting block 38 extends out of the edge of the push plate 35. A sliding groove 381 adapted to the limiting block 38 is opened on the inner wall of the tank body 33 along its own axial direction. A limiting groove 382 for the limiting block 38 to be engaged is opened at one end of the sliding groove 381 close to the drone body 1. During the movement of the push plate 35, the limiting block 38 cooperates with the sliding groove 381 to be slidably connected in the sliding groove 381. When the push plate 35 moves to a side close to the drone collective, the limiting block 38 is located at the end of the sliding groove 381 and is aligned with the limiting groove 382. The electric push rod 36 is hinged to the push plate 35, and the output end of the electric push rod 36 is hinged to the connecting rod 37. The output end of the electric push rod 36 extends out, pushing the limiting part to rotate relative to the push plate 35, so that the limiting block 38 can be embedded in the limiting groove 382, ​​thereby limiting the movement of the push plate 35 in the tank body 33. When the push plate 35 is locked, the push plate 35 can be prevented from continuously squeezing the solvent soft bag 34, and the solvent soft bag 34 can be prevented from being squeezed and damaged, thereby protecting the solvent soft bag 34.

[0040] In order to further prevent the flame retardant from being blown away by the wind during the spraying process, in the embodiment of the present application, a guide tube 6 is coaxially arranged on the outer side of the outermost telescopic branch pipe 21. Both ends of the guide tube 6 are open, and the end of the guide tube 6 away from the drone body 1 is the smaller end of the guide tube 6. A guide channel is formed between the guide tube 6 and the telescopic branch pipe 21, and the top opening of the guide tube 6 is located below the flight power system. Through the guide tube 6, part of the downward airflow in the flight power system can be collected and blown out along the flame retardant spraying direction, reducing the impact of crosswind on the flame retardant.

[0041] Furthermore, the mounting frame 11 is rotatably connected relative to the drone body 1, and the drone body 1 is also provided with a second limit assembly for limiting the rotation of the mounting frame 11. Specifically, two parallel mounting plates 12 are provided on both sides of the mounting frame 11 on the drone body 1, a rotating shaft is provided on the mounting frame 11, and the mounting frame 11 is rotatably connected to the mounting plate 12 via the rotating shaft, a first pin hole group is provided on the mounting frame 11, and at least two second pin hole groups are provided on the mounting plate 12 at intervals along the circumference of the rotating shaft, and the second limit assembly includes a limit pin 13, and the limit pin 13 limits the rotation of the mounting frame 11 by simultaneously passing through the first pin hole group and the second pin hole group. In the embodiment of the present application, in the two limit states of the mounting frame 11, the telescopic tube assembly 2 is respectively in a state of being vertically arranged relative to the UAV body 1 and in a state of being at any angle between 0° and 30° relative to the horizontal plane. In addition to being able to operate in natural environments such as forest farms and grasslands to spray flame retardants downwards, the UAV body 1 in the present application can also be used to spray flame retardants on the facades of high-rise buildings in the city, thereby increasing the scope of use of the UAV.

[0042] Furthermore, the guide tube 6 includes a fixed ring 61, a movable ring 62 and a telescopic sleeve 63. The fixed ring 61 and the movable ring 62 are connected by the telescopic sleeve 63. The fixed ring 61 is fixedly connected to the UAV body 1, and the movable ring 62 is fixedly connected to the outermost telescopic branch pipe 21. When the mounting frame 11 is flipped, the telescopic sleeve 63 is flipped accordingly, which also plays a role in reducing the phenomenon of the flame retardant being blown away by the wind.

[0043] It should be understood by those skilled in the art that, although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments once those skilled in the art are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A UAV flame retardant spraying system, characterized in that: The invention comprises an unmanned aerial vehicle body (1), wherein a mounting frame (11) is arranged at the bottom of the unmanned aerial vehicle body (1), a telescopic tube assembly (2) is arranged on the mounting frame (11), a flame retardant spraying system is arranged at the movable end of the telescopic tube assembly (2), and a first driving assembly for driving the telescopic tube assembly (2) to extend or retract its length is arranged on the unmanned aerial vehicle body (1); The flame retardant spraying system comprises a solvent tank (3) for containing the flame retardant, a spraying port (31) is arranged at the bottom of the solvent tank (3), an electronic valve (32) for opening and closing the spraying port (31) is arranged on the solvent tank (3), and a booster assembly is arranged on the mounting frame (11); The telescopic tube assembly (2) comprises a plurality of telescopic branch tubes (21) coaxially slidably sleeved, the top of the telescopic branch tube (21) is provided with an anti-detachment hook portion (22) folded outward twice, the bottom of the telescopic branch tube (21) is provided with an anti-detachment overlap portion (23) folded inward twice, a sealing ring is provided between the anti-detachment hook portion (22) and the anti-detachment overlap portion (23), the top end of the outermost telescopic branch tube (21) is connected to the mounting frame (11), and the bottom end of the innermost telescopic branch tube (21) is detachably connected to the solvent tank (3); The first driving assembly comprises a driving motor (41), a winding drum (42), a receiving wire (43) and a pulley (44); the pulley (44) is rotatably arranged at the bottom end of the innermost telescopic branch pipe (21); the winding drum (42) is rotatably arranged on the mounting frame (11) and is located on one side of the telescopic tube assembly (2); the driving motor (41) is used to drive the winding drum (42) to rotate; the receiving wire (43) is wound on the winding drum (42); one end of the receiving wire (43) is fixedly connected to the winding wire, and the other end is fixedly connected to the mounting frame (11) after winding around the pulley (44); The pressurizing assembly comprises a compressed gas cylinder (51) and a first connector; a sealing cover (24) for sealing the top of the telescopic branch pipe (21) is provided at the top end of the outermost telescopic branch pipe (21); a sealed air cavity (26) is formed between the sealing cover (24) and the telescopic pipe assembly (2); the first connector is provided on the sealing cover (24) and communicates with the air cavity (26); the compressed gas cylinder (51) is connected to the first connector; and an electronic exhaust valve (25) for exhaust is provided on the sealing cover (24); The solvent tank (3) comprises a tank body (33), a solvent soft bag (34) and a push plate (35); the tank body (33) is detachably arranged at the bottom end of the innermost telescopic branch pipe (21); the top of the tank body (33) is open; the solvent soft bag (34) is arranged in the tank body (33); a liquid outlet is arranged on the solvent soft bag (34); the liquid outlet is detachably connected to the spraying port (31) at the bottom of the tank body (33); the push plate (35) is coaxially slidably arranged in the tank body (33) above the solvent soft bag (34); the top opening of the tank body (33) is connected to the air cavity (26) in the telescopic tube assembly (2).

2. The flame retardant spraying system for unmanned aerial vehicles according to claim 1, characterized in that: The sealing cover (24) is provided with an electronic safety valve (27).

3. The flame retardant spraying system for unmanned aerial vehicles according to claim 1, characterized in that: The tank body (33) is provided with a slide rail, the push plate (35) is coaxially slidably connected in the tank body (33), and a first limit assembly for limiting the movement of the push plate (35) is provided in the tank body (33). The first limit assembly includes a limit part and an electric push rod (36). The limit part is provided on a side of the push plate (35) away from the solvent soft bag (34). The limit part includes a limit block (38) and a connecting rod (37). One end of the connecting rod (37) is coaxially hinged with the push plate (35), and the other end is The tank body (33) is fixedly connected to a limit block (38), the limit block (38) extends out of the push plate (35) and can rotate coaxially with respect to the push plate (35), a slide groove (381) adapted to the limit block (38) is provided on the inner wall of the tank body (33), and a limit groove (382) for the limit block (38) to engage is provided at one end of the slide groove (381) close to the UAV body (1), the electric push rod (36) is arranged on the push plate (35), and the output end of the electric push rod (36) is hinged to the connecting rod (37).

4. A UAV flame retardant spraying system according to any one of claims 1 to 3, characterized in that: A flow guide tube (6) is coaxially arranged on the outer side of the outermost telescopic branch tube (21), the two ends of the flow guide tube (6) are open, the end of the flow guide tube (6) away from the drone body (1) is the smaller end of the flow guide tube (6), and a flow guide channel is formed between the flow guide tube (6) and the telescopic branch tube (21); The drone body (1) is provided with a flight power system, and the top opening of the guide tube (6) is located below the flight power system.

5. The UAV flame retardant spraying system according to claim 4, characterized in that: The mounting frame (11) is rotatably connected relative to the drone body (1), and a second limiting component for limiting the rotation of the mounting frame (11) is provided on the drone body (1); The second limiting component comprises a limiting pin (13); two mutually parallel mounting plates (12) are arranged on both sides of the mounting frame (11) on the drone body (1); a rotating shaft is arranged on the mounting frame (11); the mounting frame (11) is rotatably connected to the mounting plate (12) via the rotating shaft; a first pin hole group is provided on the mounting frame (11); at least two second pin hole groups are provided on the mounting plate (12) at intervals along the circumference of the rotating shaft; the limiting pin (13) simultaneously passes through the first pin hole group and the second pin hole group to limit the rotation of the mounting frame (11).

6. The flame retardant spraying system for unmanned aerial vehicles according to claim 5, characterized in that: The guide tube (6) comprises a fixed ring (61), a movable ring (62) and a telescopic sleeve (63); the fixed ring (61) and the movable ring (62) are connected via the telescopic sleeve (63); the fixed ring (61) is fixedly connected to the drone body (1); and the movable ring (62) is fixedly connected to the outermost telescopic branch pipe (21).

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