Photovoltaic panel cleaning device based on the principle of air multiplier

Abstract

The application discloses a kind of photovoltaic panel cleaning device based on air multiplier principle, mainly solve the problem of big damage and poor stability of prior art to solar panel.Its cleaning device includes longitudinal frame and cleaning component, motion chassis includes horizontal frame, motor, drive wheel and sensor, cleaning component is fixed on longitudinal frame, longitudinal frame and sensor are fixed on horizontal frame, motor and drive wheel are fixed on horizontal frame.Cleaning component includes three groups of fan, air duct air supply structure and air path connecting device, they are interconnected between each other;The output shaft of the motor on both sides is equipped with a speed reducer;Two wheels of axial symmetry periphery include oblique fixed soft material around the axis.Operate, cleaning device detects the position of itself relative to photovoltaic panel by sensor, to complete the cleaning of entire photovoltaic panel in the way of serpentine movement.The application has little damage to photovoltaic panel, low cost, high work efficiency, stable operation, and can be used for normal cleaning treatment of solar panel.

Description

Technical Field

[0001] This invention belongs to the field of electronic equipment technology, and specifically relates to a photovoltaic panel cleaning device that can be used for routine cleaning of solar panels. Background Technology

[0002] Solar energy, as a clean energy source, is one of the key development directions for future energy. With the development of the solar energy industry, the number and size of photovoltaic (PV) panels are increasing. However, as these panels are used over time, dust inevitably accumulates, weakening solar energy and damaging the panels due to the heat island effect. To address the growing cleaning needs of PV panels, various cleaning devices have emerged, mainly involving cleaning on the panel itself and cleaning underneath and on top of the panel. On-panel cleaning often uses roller-brush-like devices that directly contact the PV panel for cleaning. Cleaning underneath and on top of the panel often uses air pump-type devices. Both of these cleaning methods have their own shortcomings.

[0003] Patent document CN202020214107.7 discloses a photovoltaic panel cleaning robot based on negative pressure adsorption. This robot uses a panel-based cleaning method and includes a walking device, a battery, a waterless cleaning device, an image acquisition device, a communication and control device, and a negative pressure adsorption device. The negative pressure adsorption device includes a high-speed motor, a centrifugal fan, an upper base plate, a lower base plate, and a flow-blocking strip. The upper base plate covers the lower base plate, and the lower base plate is fixed below the upper base plate. An air inlet is located at the center of the lower base plate, and the edges of the lower base plate are not connected to the edges of the upper base plate, leaving gaps to form a flow-guiding cavity between them. The flow-blocking strip is fixed to the lower surface of the lower base plate and adheres to the photovoltaic panel. The high-speed motor is fixed to the upper base plate, and its output shaft extends into the flow-guiding cavity. A centrifugal fan is fixed to the output shaft of the high-speed motor. Because this robot cleans the photovoltaic panel through direct contact, it is prone to damaging the surface of the solar panel. Furthermore, when the device moving on the plate moves directly on the tilted solar panel, it becomes unstable due to gravity. Therefore, a large amount of electrical energy and space resources are used to generate negative pressure. Although this ensures the stable operation of the cleaning device, it also results in a lot of waste that is not related to the cleaning task.

[0004] Patent application number 202111366139.4 discloses a high-frequency airflow cleaning device for photovoltaic panels and a method for cleaning photovoltaic panels. This method combines on-panel and under-panel cleaning. The cleaning device includes a moving platform and cleaning components. The moving platform includes a manual jack and a telescopic transition plate. The cleaning components include two motors, cleaning cart stepped wheels, cleaning cart obstacle-crossing wheels, and a dust removal device. During operation, the height of the cleaning components is adjusted to align with the photovoltaic panel using the manual jack. The telescopic transition plate can be extended to bring the cleaning components close to the photovoltaic panel. The cleaning components are driven by two motors, while the dust removal device is driven by one motor, allowing it to move in two directions on the photovoltaic panel. The dust removal device uses high-frequency airflow through a multi-stage expansion chamber to remove dust from the photovoltaic panel and collects suspended dust particles blown up by the airflow through a negative pressure suction chamber. This device utilizes an air pump operating under the photovoltaic panel in conjunction with the cleaning device on top of the panel.

[0005] This results in higher costs, difficulty in deployment, and an inability to complete tasks quickly, leading to lower work efficiency. Furthermore, the areas requiring cleaning on the board are restricted by the movement of the chassis beneath, making it difficult to clean the entire area and requiring more time, thus limiting the work scope and reducing overall efficiency. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art by proposing a photovoltaic panel cleaning device based on the principle of air multiplier, which improves the damage to solar panels caused by direct contact cleaning devices, reduces costs, increases work efficiency, and minimizes resource waste while ensuring stable operation of the device.

[0007] The technical approach to achieving the objective of this invention is as follows: Damage to solar panels is reduced by employing a non-contact cleaning method. Cleaning is achieved through airflow via a duct structure, eliminating the need for an air pump and thus reducing costs. Efficiency is improved by directly placing the cleaning device on the photovoltaic panel. Positive and negative pressure devices and specially designed wheels ensure stable operation of the cleaning device on the photovoltaic panel, and negative pressure resources are absorbed by a guide cavity within the duct structure that requires a smaller airflow, avoiding resource waste.

[0008] Based on the above ideas, the technical solution of this invention is implemented as follows:

[0009] A photovoltaic panel cleaning device based on the principle of air multiplier includes a cleaning device and a moving chassis. The cleaning device includes a longitudinal frame 1 and a cleaning component 2. The moving chassis includes a transverse frame 3, a motor 4, drive wheels 5, and sensors 6. The cleaning component 2 is fixed to the longitudinal frame 1. The longitudinal frame 1 and the sensors 6 are fixed to the transverse frame 3. The transverse frame 3 is fixed to the motor 4. The motor 4 and the drive wheels 5 are axially and radially engaged. The device is characterized by:

[0010] The cleaning component 2 includes three sets of fans 21, 22, and 23, an air duct air supply structure 24, and an air duct connection device 25. The three sets of fans are connected to the air duct air supply structure through the air duct connection device.

[0011] The motor 4 is a hollow cup DC motor with two output shafts on both sides, each equipped with a reducer. 6 ;

[0012] The drive wheel 5 includes a pair of axially symmetrical wheels 51 and 52. The hub of each wheel includes a soft material that is obliquely fixed around the axis so that it is arranged in a herringbone pattern after installation.

[0013] Furthermore, each of the three sets of fans 21, 22, and 23 includes a front housing, a rear housing, a multi-layered dust collection plate, a DC motor, a V-belt, fan blades, bearings, and a fan bracket. The front housing and the rear housing are fastened together and fixed. The multi-layered dust collection plate is tightly attached to the inside of the front housing. The DC motor transmits power to the fan blades through the V-belt. The fan blades form a rotating pair with the fan bracket through the bearings. The fan bracket is fixed to the four corners of the front housing.

[0014] Furthermore, the three sets of fans 21, 22, and 23 are respectively fixed to the left rear, front rear, and right rear of the air duct structure 24 via the longitudinal frame 1. The suction surface of the second set of fans 22 faces upward, drawing in a large amount of air from top to bottom to form a positive pressure zone. The suction surfaces of the first set of fans 21 and the third set of fans 23 face downward, drawing in a small amount of air from bottom to top to form a negative pressure zone. Under the combined action of the positive and negative pressure zones, the force perpendicular to the inclined plane is distributed to the drive wheels 5 on the left and right sides of the longitudinal frame 1. Combined with the anti-slip function of the drive wheels, relative sliding between the cleaning device and the photovoltaic panel is avoided.

[0015] Furthermore, the air duct air supply structure 24 includes an air inlet 241, an air outlet 242, a main cavity 243, a guide cavity 244, a partition hole 245, two main air supply slots 246 and 247, and two auxiliary air supply slots 248 and 249.

[0016] Furthermore, the two main air supply slots 246 and 247 at the upper end directly supply air to the main cavity 243, and the auxiliary air supply slots 248 and 249 blow the guiding airflow into the guiding cavity 244, and distribute the guiding airflow into the main cavity 243 through the spaced square holes 245, so that the gas in the main cavity 243 is blown out from the small gaps of the air outlet 242.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The cleaning device of the present invention employs a non-contact cleaning method by using three sets of fans to supply air to the air duct structure through an air duct connection device and then exhausting air from the air duct structure. Compared with direct cleaning devices, this method reduces damage to the photovoltaic panels when cleaning them. At the same time, due to the air duct structure designed based on the principle of air multiplier, the air force provided by the fans can achieve a better cleaning effect. Compared with other non-contact cleaning devices, this method significantly reduces costs.

[0019] 2. This invention changes the force distribution perpendicular to the inclined plane by using three sets of fans to generate positive and negative pressure. By employing a dual-output shaft reducer motor in conjunction with a drive wheel, it is directly installed on the photovoltaic panel. Compared to the method of coordinating on and under the panel, it can be quickly deployed and installed during operation, improving work efficiency. Compared to other devices that clean directly on the photovoltaic panel, it is more stable during operation, and the positive and negative pressure generated by the supply fans reduces resource waste compared to other negative pressure cleaning devices. Attached Figure Description

[0020] Figure 1 This is an overall structural block diagram of the present invention;

[0021] Figure 2 This is an isometric schematic diagram of the overall structure of the present invention;

[0022] Figure 3 This is a bottom view of the overall structure of the present invention;

[0023] Figure 4 This is an overall schematic diagram of the fan assembly in this invention;

[0024] Figure 5 This is a comparison diagram of the fan blades of different fan groups in this invention;

[0025] Figure 6 This is a schematic diagram of the external structure of the air duct in this invention;

[0026] Figure 7 This is a schematic diagram of the internal structure of the air duct in this invention;

[0027] Figure 8 This is a schematic diagram of the tire arrangement in this invention;

[0028] Figure 9 This is a schematic diagram of the invention moving horizontally. Detailed Implementation

[0029] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] Reference Figure 1 This example includes a cleaning device and a moving chassis. The cleaning device includes a longitudinal frame 1 and a cleaning assembly 2. The moving chassis includes a transverse frame 3, a motor 4, drive wheels 5, and sensors 6. The longitudinal frame 1 includes five components, namely 11-15. The cleaning assembly 2 includes an air duct supply structure 24, an air duct connection device 25, and three sets of fans 21, 22, and 23. The transverse frame 3 includes nine components, namely 31-39. The motor 4 includes four identical hollow-cup DC brushless motors 41-44. The drive wheels 5 are eight in pairs, namely 51 and 52, 53 and 54, 55 and 56, and 57 and 58. Each component in cleaning assembly 2 is fixed to the corresponding component in longitudinal frame 1. Each component in longitudinal frame 1 is fixed to the corresponding component in transverse frame 3. Sensor 6 is fixed to the corresponding component in transverse frame 3. Each component in transverse frame 3 is fixed to the corresponding motor 41 to 44. The four motors 41 to 44 are respectively axially and radially engaged with four sets of drive wheels 51 and 52, 53 and 54, 55 and 56, 57 and 58.

[0031] Reference Figure 2 and Figure 3 The longitudinal frame 1 described in this example includes a double-sided frame 11, two large supports 12 and 15, and two small supports 13 and 14; the transverse frame 3 includes a main frame 31 and eight identical flange supports 32, 33, 34, 35, 36, 37, 38, and 39, wherein flange supports 32, 33, 38, and 39 are fixed on the left side of the main frame 31, and flange supports 34, 35, 36, and 37 are fixed on the right side of the main frame 31; the air duct connection device 25 includes two large slot joints 251 and 252, two small slot joints 253 and 254, two air nozzle joints 255 and 256, and one three-way air nozzle joint 257; the four motors 41, 42, 43, and 44 each have two output shafts at both ends, and each motor is equipped with a 17:1 planetary reducer at both ends, that is, the first motor 41 is connected to the first set of reducers 411 and 412 at both ends. The two ends of the second motor 42 are connected to the second set of reducers 421 and 422, the two ends of the third motor 43 are connected to the third set of reducers 431 and 432, and the two ends of the fourth motor 44 are connected to the fourth set of reducers 441 and 442.

[0032] The air duct supply structure 24 is mounted on the main frame 31 via a double-sided frame 11. It is located at the forefront of the cleaning movement direction to ensure that the drive wheel 5 moves on the cleaned photovoltaic panel and prevents the device from slipping due to dust. The second fan group 22 is fixed to the transverse main frame 31 via two small supports 13 and 14. It is located directly behind the air duct supply structure 24, forming an upward air intake surface, which draws in a large amount of air into the air duct structure and creates a positive pressure zone. The first fan group 21 and the third fan group 23 are fixed to the transverse main frame 31 via two large supports 12 and 15, respectively, and are located to the left and right rear of the air duct supply structure 24, respectively, forming a downward air intake surface. Since these two fan groups are relatively close to the external solar panels, they can easily create a negative pressure zone while drawing in less air than the fan group 22. Under the combined action of positive and negative pressure zones, the force perpendicular to the inclined plane increases and is distributed only on the left and right sides of the transverse main frame 31. The flange supports 32, 33, 38, 39 on the left and the flange supports 34, 35, 36, 37 on the right are connected to the drive wheel 5 through the motor 4, thereby transmitting the force to the photovoltaic panel and preventing relative sliding between the cleaning device and the photovoltaic panel, so as to ensure the stable operation of the device during operation.

[0033] The first air nozzle connector 255, the three-way air nozzle connector 257, and the second air nozzle connector 256 in the air duct connection device 25 are fixed and connected to the three fan groups 21, 22, and 23, respectively; the two air nozzle connectors 255 and 256 are connected to the two small slot connectors 253 and 254 through flexible hoses; the three-way air nozzle connector 257 is connected to the two large slot connectors 251 and 252 through flexible hoses. These slot connectors 251, 252, 253, and 254 are fixed and connected to the air duct air supply structure 24, respectively.

[0034] The first set of reducers 411 and 412 are fixed to the first set of flange supports 32 and 33 on the left side, and are axially and radially fixed to the drive wheels 51 and 52 respectively; the second set of reducers 421 and 422 are fixed to the first set of flange supports 34 and 35 on the right side, and are axially and radially fixed to the drive wheels 53 and 54 respectively; the third set of reducers 431 and 432 are fixed to the second set of flange supports 36 and 37 on the left side, and are axially and radially fixed to the drive wheels 55 and 56 respectively; the fourth set of reducers 441 and 442 are fixed to the second set of flange supports 38 and 39 on the right side, and are axially and radially fixed to the drive wheels 57 and 58 respectively. This is used to provide sufficient power to the cleaning device and can complete the straight or turning movements of the device by controlling four independent motors.

[0035] Reference Figure 4 and Figure 5The first set of fans 21 includes a front housing 211, a rear housing 212, a multi-layer dust collection plate 213, a DC motor 214, a V-belt 215, fan blades 216, and a fan bracket 217. The front housing 211 and the rear housing 212 are fastened together. The multi-layer dust collection plate 213 is close to the inside of the front housing 211, thereby adsorbing dust in the air. At the same time, the multi-layer dust collection plate 213 is a quick-release structure and can be replaced after working for a period of time. The high-speed DC motor 214 transmits power to the fan blades 216 through the V-belt 215. The fan blades 216 form a rotating pair with the fan bracket 217 through bearings. The fan bracket is fixed to the four corners of the front housing 211. When working, the fan blades rotate clockwise, blowing air from the front housing to the rear housing, which serves as the airflow input for the cleaning device.

[0036] The third group of fans 23 has the same structure and volume as the first group of fans 21.

[0037] The structure of the second fan group 22 is the same as that of the first fan group 21, but the size of its fan blades 226 is 1.25 times that of the first fan blades 216, so as to provide more sufficient airflow for cleaning through the second fan group 22.

[0038] Reference Figure 6 and Figure 7 The air supply structure 24 of the air duct has an overall structure of circular groove, including two main air supply slots 246 and 247, two auxiliary air supply slots 248 and 249, an air inlet 241, an air outlet 242, a main cavity 243, a guide cavity 244, and a spacer hole 245.

[0039] The two main air supply slots 246 and 247 are located on one side outside the long side of the main cavity 243 and are arranged symmetrically with respect to the center vertical line of the long side of the main cavity; the two auxiliary air supply slots 248 and 249 are located on one side outside the long side of the guide cavity 244 and are arranged symmetrically with respect to the center vertical line of the long side of the guide cavity. This bidirectional air intake method increases the local pressure in the main cavity and improves the air outlet velocity of the main cavity.

[0040] The two main air supply slots 246 and 247 directly supply air to the main cavity 243; the two auxiliary air supply slots 248 and 249 blow guide airflow into the guide cavity 244, and distribute the guide airflow into the main cavity 243 through the spaced square holes 245, so that the gas in the main cavity 243 is blown out from the small gaps of the air outlet 242. According to Bernoulli's principle, the pressure at the air outlet decreases, which allows the air inlet 241 to draw in a large amount of air and blow a large amount of air out evenly from the air outlet 242.

[0041] The air outlet 242 has a slope of 1:20 and an air volume 1.5 times that of the air inlet 241. The air inlet has an outer slope of 1:15 and an inner slope of 1:1.5. This slope parameter setting can ensure that the pressure difference between the air inlet and the air outlet is large enough, thereby increasing the airflow utilization rate.

[0042] The spaced square holes 245 are evenly arranged on the long side of the main cavity 243 and close to the side of the guide cavity 244 to ensure the guiding function of the guide cavity.

[0043] Reference Figure 8 The first set of axially symmetrical wheels 51 and 52 each includes a set of double-strand soft materials 511 and 521 and an alloy hub 512 and 522. Each hub has a set of fixing holes at both ends, and the soft material is evenly wound around the outer periphery of the alloy hub and fixed through the holes at both ends. The two wheels are wound in opposite ways, i.e., left higher than right or left lower than right, forming a herringbone arrangement after installation. This arrangement is mainly used to ensure that when the device moves horizontally on the solar panel, the vertical contact line between the drive wheel and the inclined plane is longer and there are more contact points. At the same time, the herringbone arrangement ensures that the forces parallel to the inclined plane generated by the two wheels during movement cancel each other out, preventing the device from sideslipping. The soft material is made of rubber, polyurethane, or other plastic polymers to increase the contact area between the drive wheel and the solar panel, thereby further increasing the friction between the wheel and the photovoltaic panel and ensuring the stability of the device during operation. The second set of drive wheels 53 and 54, the third set of drive wheels 55 and 56, and the fourth set of drive wheels 57 and 58 have the same structure as the first set.

[0044] Reference Figure 9 The working principle of this example is as follows:

[0045] Before use, place this cleaning device in the lower left corner of the photovoltaic solar panel. After installing the multi-layered dust collection plate, power is supplied by an external power cord. The three sets of fans 21, 22, and 23 start running, delivering airflow into the air duct structure 24 for cleaning. The first set of fans 21 and the third set of fans 23 provide negative pressure for the cleaning device, while the second set of fans 22 draws air upwards to provide positive pressure. Under the combined action of the positive and negative pressure areas, the force of the cleaning device perpendicular to the inclined plane is distributed on the drive wheel that directly contacts the solar panel. At this point, the cleaning process officially begins. The cleaning device cleans in a serpentine motion, with the specific actions as follows:

[0046] The cleaning device starts moving parallel to the right from the lower left corner of the photovoltaic panel. After the edge is detected by sensor 6, it moves out of the maximum length of the cleaning device and locks the two sets of wheels on the left. This causes the right motor to rotate, and the cleaning device's leftward rotation is adjusted by differential speed. When sensor 6 detects that the cleaning device is horizontal, it moves vertically upward until it reaches the maximum length of the cleaning device. Then, the two sets of wheels on the left are locked, and the right motor rotates, and the cleaning device's leftward rotation is adjusted by differential speed. When sensor 6 detects that the cleaning device is vertical, it starts moving to the left. This completes the parallel movement of the cleaning device to the right.

[0047] It then begins to move parallel to the left until sensor 6 detects the edge and exits the device to its maximum length. It then locks the two sets of wheels on the right and the left motor rotates to adjust the cleaning device's rightward rotation through differential speed. When sensor 6 detects that the cleaning device is horizontal, it moves vertically upward until it reaches the maximum length of the cleaning device. Then, it locks the two sets of wheels on the right and the left motor rotates to adjust the cleaning device's rightward rotation through differential speed. When sensor 6 detects that the device is vertical, it forms the initial rightward movement posture, thus completing the parallel movement to the left.

[0048] This left-and-right movement is repeated until all areas of the photovoltaic panel are cleaned. During this process, the cleaning effect is ensured by the air duct structure, and the stability of the cleaning device is guaranteed by the positive and negative pressure generated by the fan assembly and the increased friction of the drive wheels.

[0049] The above description is merely a specific example of the present invention and does not constitute any limitation on the present invention. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and details without departing from the principles and structure of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the protection scope of the claims of the present invention.

Claims

1. A photovoltaic panel cleaning device based on the principle of air multiplier, comprising a cleaning device and a moving chassis, the cleaning device comprising a longitudinal frame (1) and a cleaning component (2), the moving chassis comprising a transverse frame (3), a motor (4), a drive wheel (5) and a sensor (6), the cleaning component (2) being fixed on the longitudinal frame (1), the longitudinal frame (1) and the sensor (6) being fixed on the transverse frame (3), the transverse frame (3) being fixed on the motor (4), the motor (4) and the drive wheel (5) being axially and radially coupled, characterized in that: The cleaning component (2) includes three sets of fans (21, 22, 23), an air duct air supply structure (24), and an air duct connection device (25). The three sets of fans are connected to the air duct air supply structure through the air duct connection device. The air supply structure (24) includes an air inlet (241), an air outlet (242), a main cavity (243), a guide cavity (244), a partition hole (245), a main air supply slot (246, 247), and a secondary air supply slot (248, 249). The two main air supply slots (246, 247) directly supply air to the main cavity (243), and the auxiliary air supply slots (248, 249) blow the guide airflow into the guide cavity (244), and distribute the guide airflow into the main cavity (243) through the spacer hole (245), so that the gas in the main cavity (243) is blown out from the small gap of the air outlet (242), which drives the air inlet (241) to draw in a large amount of air, and blows out a large amount of air evenly from the air outlet (242); The motor (4) is a hollow cup DC motor with two output shafts on both sides and a reducer is installed on each of them. The drive wheel (5) includes a pair of axially symmetrical wheels (51, 52), and the hub of each wheel includes a soft material that is obliquely fixed around the axis so that it is arranged in a herringbone pattern after installation.

2. The apparatus according to claim 1, characterized in that, The first fan (21) includes a front housing (211), a rear housing (212), a multi-layer dust collection plate (213), a DC motor (214), a V-belt (215), fan blades (216), and a fan bracket (217). The front housing (211) is fastened and fixed to the rear housing (212). The multi-layer dust collection plate (213) is tightly attached to the inside of the front housing (211). The DC motor (214) transmits power to the fan blades (216) through the V-belt (215). The fan blades (216) form a rotating pair with the fan bracket (217) through bearings. The fan bracket is fixed to the four corners of the front housing (211).

3. The apparatus according to claim 1, characterized in that, The third group of fans (23) and the first group of fans (21) The structure and volume are the same; the structure of the second fan (22) is the same as that of the first fan (21), and the size of its fan blade (226) is 1.25 times that of the first fan blade (216).

4. The apparatus according to claim 1, characterized in that, Three sets of fans (21, 22, 23) are fixed to the left rear, front rear, and right rear of the air supply structure (24) via the longitudinal frame (1). The suction surface of the second set of fans (22) faces upward, drawing in a large amount of air from top to bottom to form a positive pressure zone. The suction surfaces of the first set of fans (21) and the third set of fans (23) face downward, drawing in a small amount of air from bottom to top to form a negative pressure zone. Under the combined action of the positive and negative pressure zones, the force perpendicular to the inclined plane is distributed to the drive wheels (5) on the left and right sides of the longitudinal frame (1), preventing relative sliding between the cleaning device and the photovoltaic panel.

5. The apparatus according to claim 4, characterized in that: The air outlet (242) has a slope of 1:20 and an air volume that is 1.5 times that of the air inlet (241); The air inlet has an outer slope of 1:15 and an inner slope of 1:1.

5. The two main air supply slots (246, 247) are arranged symmetrically with respect to the center vertical line of the main cavity on one side outside the long side of the main cavity (243). The two auxiliary air supply slots (248, 249) are arranged symmetrically with respect to the center vertical line of the long side of the guide cavity (244) on one side outside the long side of the guide cavity.

6. The apparatus according to claim 4, characterized in that: The spacer holes (245) are evenly arranged on the long side of the main cavity (243) and close to the guide cavity (244).

7. The apparatus according to claim 1, characterized in that, The air duct connection device (25) includes four slotted connectors (251, 252, 253, 254) and three air nozzle connectors (255, 256, 257). The slotted connectors (253, 254) and air nozzle connectors (255, 256) are paired in pairs, and the slotted connectors (251, 252) and air nozzle connectors (257) are paired in a two-to-one manner, and each is connected by a hose.

8. The apparatus according to claim 1, characterized in that: A pair of axially symmetrical wheels (51, 52) each include a set of double-strand soft material and an alloy hub. Each hub has a set of fixing holes at both ends. The soft material is evenly wrapped around the outer periphery of the alloy hub and fixed through the holes at both ends. The two wheels are wrapped in opposite ways, i.e., left high and right low or left low and right high.

9. The apparatus according to claim 1, characterized in that... The soft material mentioned is made of rubber, polyurethane, or other plastic polymers.

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