CN111215272B

CN111215272B - Filter spraying device

Info

Publication number: CN111215272B
Application number: CN202010197926.XA
Authority: CN
Inventors: 陈庆平; 王益康; 陈积兰; 张林全; 方向; 陈锦锦; 姚潘姗
Original assignee: Zhejiang Lifeng Machinery Parts Co ltd
Current assignee: Zhejiang Lifeng Machinery Parts Co ltd
Priority date: 2020-03-19
Filing date: 2020-03-19
Publication date: 2024-05-07
Anticipated expiration: 2040-03-19
Also published as: CN111215272A

Abstract

The invention discloses a filter spraying device which comprises a spraying system and a plastic powder recovery system, wherein the spraying system comprises a unidirectional conveying assembly and a spray gun, the unidirectional conveying assembly comprises a conveying chain and carriers, the carriers are movably mounted on the conveying chain in a rotating mode and are equidistantly arranged on the conveying chain, the conveying chain penetrates through the plastic powder recovery system, the spray gun is positioned in the plastic powder recovery system, and the spraying range of the spray gun faces to the carriers on the conveying chain. The filter spraying device promotes plastic powder to be more uniformly distributed at all parts of the shell of the filter by improving the rotation quantity and the rotation angle of the carrier, and the uniformity of the shell spraying operation of the filter is effectively improved.

Description

Filter spraying device

Technical Field

The invention relates to a filter spraying device.

Background

The surface of the filter is covered with a protective layer, so that the filter has an antirust protective effect and can be more attractive in appearance. The protective layer is processed by adopting a plastic spraying process, a carrier is arranged on a circulating conveying path constructed by a chain, a shell of the filter to be processed is placed on the carrier, a spray gun is arranged at a specific working position, when the carrier carries the shell of the filter and passes through the spray gun, the shell of the filter can receive plastic powder sprayed by the spray gun, and finally, a protective layer is formed on the shell of the filter. Because the whole body of the shell of the filter needs to be sprayed with plastic powder, all parts of the shell of the filter must be ensured to enter the injection range of the spray gun. In the prior art, in order to ensure that the whole body of the shell of the filter can enter the injection range of the spray gun, a top injection technology is generally adopted, namely, the spray gun is arranged at a higher position, the injection direction of the spray gun is vertically downward, and the surface of the shell of the filter can be exposed in a vertically downward visual angle, so that plastic powder can be sprayed on most of the surface of the shell of the filter by adopting the top injection technology. However, no molding is obtained at the recess of the housing of the filter, since these surface structures cannot be present in the vertically downward view. In order to further make up for the technical defects, the prior art also provides a technical scheme for enabling the carrier to rotate at the spraying station and spray plastic powder from the horizontal direction. According to the technical scheme, the surface of the carrier is provided with the transmission teeth, the spraying station is provided with the space position fixing rack, when the carrier passes through the position of the rack, the transmission teeth on the carrier are meshed with the transmission teeth on the rack, and when the carrier moves forwards, the carrier can move forwards and rotate simultaneously under the driving action of the rack. According to the technical scheme, all parts of the shell of the filter can enter the injection range of the spray gun, but the rotation amount of the carrier in the injection range of the spray gun is very limited, the rotation angle is smaller than two hundred seventy degrees, and the plastic powder amount on one side of the shell of the filter is much larger than that on other parts, so that the plastic powder spraying uniformity effect is poor.

Disclosure of Invention

The invention aims to solve the technical problem of improving the uniformity of the spraying operation of the shell of the filter, thereby obtaining the spraying device of the filter.

In order to solve the technical problems, the invention adopts the following technical scheme: the spray coating device of the filter comprises a spray coating system and a plastic powder recycling system, wherein the spray coating system comprises a unidirectional conveying component and a spray gun, the unidirectional conveying component comprises a conveying chain and a carrier, the carrier is movably mounted on the conveying chain in a rotating mode and is equidistantly arranged on the conveying chain, the conveying chain penetrates through the plastic powder recycling system, the spray gun is positioned in the plastic powder recycling system, the spray range of the spray gun faces the carrier on the conveying chain, the side surface of the carrier is provided with a transmission tooth, the spray coating system is further provided with an active rotating component, the active rotating component comprises a linear cylinder and a rack, the rack is fixedly connected with a piston rod of the linear cylinder, the direction of the movement of the linear cylinder is parallel to the conveying direction of the unidirectional conveying component, the rack body is protruded to one side, the rack is provided with a transmission tooth at the protrusion, the movement range of the transmission tooth of the carrier is intersected with the movement range of the transmission tooth of the rack, the spray gun is movably connected with the carrier through the engagement of the transmission tooth, the spray gun is annularly distributed on two sides of the conveying chain and in the same horizontal plane, the spray gun is intersected with the same area, and the movement range of the spray gun is located in the same area.

After the active rotating component works, more rotating quantity and rotating angle can be provided for the carrier in the original moving stroke of the carrier, and the shell of the filter positioned on the carrier can rotate more, so that the key component for obtaining uniform spraying is obtained; for a single carrier, after the linear cylinder stretches and stretches to drive the rack, the carrier can rotate positively and negatively, the rotation amount and the rotation angle can be increased by three times, and the single rotation angle can exceed three hundred and sixty degrees. In the technical scheme, the spray guns are distributed around the carrier instead of on one side of the carrier, which is the main reason that the spray guns are distributed annularly at equal angles in the same horizontal plane, so that a better uniform spraying effect can be obtained; in addition, the spraying range of the spray gun faces to a fixed circle center position, so that the optimal air flow opposite impact effect can be achieved, and the plastic powder diffusion range can be reduced.

The adhesive capability of the plastic powder can still be normally exerted when the plastic powder is diffused in the air to move along with the airflow, so that the plastic powder diffused in the air can be utilized to have positive significance for the shell of the filter on the carrier outside the spraying station. For this purpose, the distribution length of the driving teeth on the rack is set to a value greater than three times the distance between adjacent carriers, which not only greatly increases the rotation amount and rotation angle of the carriers, but also can be the rotation of the outer shell of the filter on the carrier outside the injection station to uniformly receive a small amount of diffused molding powder.

The optimal distribution structure of the spray guns is that two spray guns are arranged on two sides of a conveying chain respectively, namely, the interval angle of annular distribution of the spray guns is ninety degrees.

According to the technical scheme, in order to recycle the diffused plastic powder so as to facilitate secondary utilization, a plastic powder recycling system is optimized. The plastic powder recovery system comprises a floor-type negative pressure bin, a steady flow conveying air channel, an exhaust unit, a coarse grain collector and a fine dust collector, wherein a cavity is arranged in the floor-type negative pressure bin, the bottom end of the floor-type negative pressure bin is of an opening structure, a conveying chain penetrates through the cavity, the movement range of the carrier is intersected with the cavity, the positions of a spray gun and a rack provided with transmission teeth are all positioned in the cavity, the exhaust unit is arranged at the top end of the floor-type negative pressure bin, the air inlet end of the exhaust unit is communicated with the cavity, the steady flow conveying air channel is of a straight tubular structure, the exhaust unit is connected with one end of the steady flow conveying air channel, the air outlet end of the exhaust unit is communicated with the interior of the steady flow conveying air channel, the other end of the steady flow conveying air channel is connected with the fine dust collector, the steady flow conveying air channel is obliquely arranged, the coarse grain collector is arranged at the middle part of the steady flow conveying air channel, the top end of the coarse grain collector is at least provided with three collection channels, the center lines of the collection channels are all positioned in the vertical direction, the collection channels are arranged in a straight direction, the coarse grain collection channels are arranged at intervals, the coarse grain storage cavities are all arranged at the bottom ends of the conveying air channel, the coarse grain storage cavities are all arranged at the bottom ends of the coarse grain storage cavities, the coarse grain storage cavities are communicated with the interior of the fine dust storage cavities, the coarse grain storage cavities are communicated with the coarse grain storage cavities, the coarse grain storage cavities are arranged at the coarse grain storage cavities, the coarse grain storage and the coarse dust storage. The exhaust passage and the fine dust discharge port are communicated with the fine dust storage cavity, a filter element is arranged in the fine dust collector, the filter element is arranged in the exhaust passage, and the fine dust collector is provided with a valve on the fine dust discharge port.

The dead weight of the plastic powder can force the plastic powder to settle after floating until the plastic powder falls on the ground or other supporting surfaces, and the technical scheme utilizes the natural law to establish a structure capable of allowing the plastic powder diffused in the air to automatically fall. The floor-type negative pressure bin is used for covering a spraying operation area and sealing the spraying operation area in the cavity, so that the diffusion range of plastic powder in air is limited to the minimum range. The internal space of the steady flow conveying air duct is long and narrow, so that the whole plastic powder recycling system needs a certain occupied space, and enough implementation conditions can be obtained in the industrial application field. The steady flow conveying air duct is obliquely arranged, so that the internal space of the steady flow conveying air duct is obliquely distributed; for flowing air flow, the moving process in the steady flow conveying air duct is a climbing process, the time required for the air flow climbing is not short based on the long and narrow characteristic of the steady flow conveying air duct, the self-falling phenomenon of plastic powder can be gradually displayed in the climbing process, and particularly, the part with larger plastic powder particles occurs in the middle climbing stage from the beginning of self-falling. The coarse grain collector is arranged at the middle part of the steady flow conveying air duct, and coarse grain plastic powder is just positioned at the position of the collecting channel in the middle stage of climbing, so that the self-descending coarse grain plastic powder naturally falls into the coarse grain storage cavity. In this technical solution, instead of using a single large-opening collecting channel, a plurality of collecting channels are provided, mainly for avoiding the stall of the airflow, because the structure of the single large-opening collecting channel can make the width of the area where the airflow flows suddenly increase and the air pressure become smaller, so that the flow speed becomes very small, so that turbulence is generated to drive the coarse-grain plastic powder to separate from the area where the coarse-grain collector is located. The long and narrow feature of the steady flow conveying air duct is designed to make the airflow flow more stable, and if coarse plastic powder is not separated and enters the fine dust collector, the secondary utilization efficiency of the plastic powder can be affected, after all, the adhesive force of the coarse plastic powder is weaker than that of the fine plastic powder. Finally, the air flow from which coarse grains are separated through self-descending enters a fine dust collector, and the fine dust collector is large enough on the inner surface of the fine dust storage cavity and can be used for adhering a large amount of fine plastic powder, so that the plastic powder which is convenient for secondary use is collected in the fine dust collector. And the air filtered by the filter element can be directly discharged to the outside. The collected coarse plastic powder and fine plastic powder can be concentrated and output after being accumulated, and then can be used for spraying plastic powder to a filter to realize secondary utilization.

In order to further ensure that the collecting channel does not generate turbulent flow to the air flow in the steady flow conveying air channel, and simultaneously ensure that the plastic powder self-descending process is smoothly carried out, the width of the end, which is communicated with the inside of the steady flow conveying air channel, of the collecting channel gradually decreases in the direction from top to bottom.

In order to improve the self-dropping efficiency of the molding powder in the steady flow conveying air duct and fully ensure that the self-dropping of the molding powder occurs at the position of the collecting channel, the width of the inside of the steady flow conveying air duct is gradually increased from bottom to top.

The invention adopts the technical scheme that: the filter spraying device promotes plastic powder to be more uniformly distributed at all parts of the shell of the filter by improving the rotation quantity and the rotation angle of the carrier, and the uniformity of the shell spraying operation of the filter is effectively improved.

Drawings

The invention is described in further detail below with reference to the drawings and the detailed description.

FIG. 1 is a schematic illustration of a filter spray device of the present invention;

FIG. 2 is a schematic view of a unidirectional transport assembly of a filter spray apparatus according to the present invention;

FIG. 3 is a schematic illustration of the use of a unidirectional transport assembly of a filter spray apparatus of the present invention.

Detailed Description

The filter spraying device comprises a spraying system and a molding powder recycling system. The spray system is used to spray molding powder onto the housing of the filter to be processed. The molding powder recovery system is used for collecting molding powder diffused into the air from the spraying system.

As shown in fig. 1, the plastic powder recycling system comprises a floor type negative pressure bin 1, a steady flow conveying air duct 3, an air draft unit 4, a coarse grain collector 5 and a fine dust collector 9.

The floor type negative pressure bin 1 is a hollow shell structure formed by welding metal plates, a cavity 2 is arranged in the middle of the body, an opening is arranged at the bottom of the body, and the cavity 2 is directly communicated with the outside through the opening to form a semi-closed structure; two symmetrical notches with the same structure are arranged on the body, and the notches are used for enabling the carrier 16 on the circulating conveying path to enter the cavity 2 with the shell of the filter through the spraying system. The edge of body bottom is straight to the body of being convenient for is direct to be connected with ground, makes cavity 2 no longer communicate with the external world through the opening, places subaerial through the bottom of body in the actual production process. The cavity 2 in the floor type negative pressure bin 1 is communicated with the outside only through the notch.

The suction unit 4 includes a housing and an electric fan. The inside of the shell is hollow, two ends of the shell are respectively provided with an opening, the electric fan is arranged inside the shell, and after the electric fan is electrified, an airflow flow path which flows unidirectionally can be established inside the shell, so that an air inlet end is formed at one opening of the shell, and an air outlet end is formed at the other opening of the shell. The air extracting unit 4 is arranged at the top end of the floor type negative pressure bin 1, the shell of the air extracting unit 4 is connected with the body of the floor type negative pressure bin 1, and the air inlet end of the air extracting unit 4 is communicated with the cavity 2 of the floor type negative pressure bin 1.

The steady flow air delivery duct is of a straight tubular structure, the air draft unit 4 is connected with one end of the steady flow air delivery duct 3, the air outlet end of the air draft unit 4 is communicated with the interior of the steady flow air delivery duct 3, and the other end of the steady flow air delivery duct 3 is connected with the fine dust collector 9. The space posture of the steady flow conveying air duct 3 is in an inclined state, and one end of the steady flow conveying air duct 3 is higher than the other end of the steady flow conveying air duct 3. The width of the inside of the steady flow conveying air duct 3 is not the same everywhere, but gradually increases from bottom to top.

The fine dust collector 9 is of a hollow shell structure, a fine dust storage cavity 10 is formed in the middle of the inside of the fine dust collector 9, an exhaust passage 11 is formed in the top end of the fine dust collector 9, a fine dust discharge port 12 is formed in the bottom end of the fine dust collector 9, the exhaust passage is communicated with the fine dust storage cavity 10, and the fine dust storage cavity 10 is communicated with the fine dust discharge port 12. The fine dust storage cavity 10 is directly communicated with the inside of the steady flow conveying air duct 3; the exhaust passage 11 and the fine dust discharging port 12 are both directly communicated with the fine dust storage cavity 10. A filter element 13 is arranged in the fine dust collector 9, and the filter element 13 is arranged in the exhaust passage 11; in order to facilitate the control, the fine dust collector 9 is provided with a valve at the fine dust outlet 12, which is closed in the initial state.

The coarse grain collector 5 is also a hollow shell structure; the top end of the coarse grain collector 5 is provided with three collecting channels 6, the middle part inside the coarse grain collector 5 is provided with a coarse grain storage cavity 7, the bottom end of the coarse grain collector 5 is provided with a coarse grain discharge port 8, the collecting channels 6 are communicated with the coarse grain storage cavity 7, and the coarse grain storage cavity 7 can be communicated with the outside through the coarse grain discharge port 8. The coarse grain storage cavity 7 is in an inverted conical structure. In order to facilitate the control, the coarse grain collector 5 is provided with a valve on the coarse grain discharge port 8, which valve is closed in the initial state. The coarse grain collector 5 is positioned below the steady flow air supply channel, and the coarse grain collector 5 is arranged at the middle part of the steady flow conveying air channel 3. After installation, the central lines of the collecting channels 6 are all positioned in the vertical direction, and the collecting channels 6 are arranged at intervals and straightly along the steady flow conveying air duct 3. One end of the collecting channel 6 is positioned below the steady flow conveying air duct 3, the collecting channel 6 is communicated with the interior of the steady flow conveying air duct 3, and the other end of the collecting channel 6 is communicated with the coarse grain storage cavity 7; the width of the end of the collecting channel 6, which communicates with the interior of the steady flow delivery duct 3, gradually decreases in the top-down direction.

As shown in fig. 2 and 3, the spray coating system includes a unidirectional delivery assembly 14, a spray gun 20, and an active rotation assembly.

The unidirectional conveying assembly 14 comprises a conveying chain 15, a carrier 16, a frame, a motor and a speed changer. The conveying chain 15 is mounted on the frame through two chain wheels, the conveying chain 15 is unfolded in the horizontal direction to form an annular structure, two ends of the conveying chain 15 are semicircular, and the middle part of the conveying chain 15 is of a straight structure. The motor and the speed changer are both arranged on the frame, an output shaft of the motor is fixedly connected with an input shaft of the speed changer, and an output shaft of the speed changer is connected with one of the chain wheels. The motor starts the rear sprocket to rotate, and then drives the conveying chain 15 to run. The conveyor chain 15 runs unidirectionally in only one direction. The carrier 16 comprises a base 17, a rotating shaft 18 and a supporting sleeve 19, wherein one base 17 is fixedly connected with only one chain link of the conveying chain 15, the rotating shaft 18 is movably arranged on the base 17 through a bearing, the supporting sleeve 19 is fixedly connected with one end of the rotating shaft 18, and the center line of the supporting sleeve 19 is overlapped with the center line of the rotating shaft 18; a sliding block for supporting the base 17 is further arranged on the frame of the unidirectional conveying assembly 14, and the supporting base 17 is in sliding connection with the sliding block; the supporting sleeve 19 is in a truncated cone-shaped structure, and the bottom edge of the side surface of the supporting sleeve is provided with transmission teeth. The supporting sleeve 19 can make autorotation motion on the conveying chain 15 relative to the base 17 and the conveying chain 15, and all the carriers 16 are in an equidistant arrangement state. When the motor is started, the conveyor chain 15 is driven to run, and the carrier 16 rotates in the horizontal plane. There are four spray guns 20 in the spray system, one on each side of the straight portion of one of the conveyor chains 15, i.e., two spray guns 20 on each side. The spray guns 20 are fixed to the frame of the unidirectional transport assembly 14, and the four spray guns 20 are mounted at the same height and in the same horizontal plane. The spray guns 20 on the two sides are symmetrically distributed relative to the straight part of the conveying chain 15, and the distances from the two spray guns 20 on the same side to the straight part of the conveying chain 15 are the same; the spacing between adjacent spray guns 20 is the same between the four spray guns 20; the spray ranges of the spray guns 20 all face one of the areas of the range of motion of the carrier 16 along with the conveyor chain 15, namely, the spray ranges of the spray guns 20 intersect in the area, the distances from the carrier 16 to each spray gun 20 are the same when the carrier 16 enters the area, the four spray guns 20 are distributed in an equal-angle annular shape with the area as the center, and the interval angle of the annular distribution of the spray guns 20 is ninety degrees, as shown in fig. 3.

The active rotating assembly comprises a linear cylinder and a rack 21. The linear cylinder is fixedly mounted on the frame of the unidirectional transport assembly 14. The rack 21 is fixedly connected with a piston rod of the linear cylinder. The rack 21 is slidably movably mounted on the frame of the unidirectional transport assembly 14, and the rack 21 is slidable in a horizontal direction. The rack 21 is located outside one of the straight portions of the conveyor chain 15 of the unidirectional conveyor assembly 14, and when the linear cylinder drives the rack 21 to move, the direction of movement of the rack 21 is parallel to the straight portion of the conveyor chain 15 of the unidirectional conveyor assembly 14, and the direction of movement of the rack 21 is parallel to the conveying direction of the unidirectional conveyor assembly 14 because the conveyor chain 15 moves unidirectionally. One side of the rack 21 protrudes outwards, the rack 21 is provided with transmission teeth at the protruding part, and the distribution length of the transmission teeth on the rack 21 is greater than three times the distance between adjacent carriers 16. After the carrier 16 passes through the area near the rack 21, the transmission teeth on the carrier 16 can be meshed with the transmission teeth on the rack 21, that is, the movement range of the transmission teeth of the carrier 16 is intersected with the movement range of the transmission teeth of the rack 21, the carrier 16 and the rack 21 are movably connected through the meshing of the transmission teeth, the rack 21 is driven by a linear cylinder to move in a translational manner, the absolute value of the translational speed of the rack 21 is far greater than the absolute value of the movement speed of the carrier 16, the interaction amount between the rack 21 and the carrier 16 is increased, more rotation amount and rotation angle of the shell of the filter positioned in the intersection area of the injection range of the spray gun 20 can be obtained, and the rotation angle of the shell can exceed three hundred sixty degrees. The linear cylinder is contracted in the initial state. The conveying chain 15 passes through the body of the floor type negative pressure bin 1 through a notch embedded in the body of the floor type negative pressure bin 1, so that a straight part of one position of the conveying chain 15 is always positioned in the cavity 2, and the carrier 16 can also enter the cavity 2 after moving along with the conveying chain 15; in addition, both the spray gun 20 and the rack 21 are located in the cavity 2 at the location where the drive teeth are provided.

When in use, the shell of the filter waiting for powder spraying operation is placed on the carrier 16, the carrier 16 moves forward on the unidirectional circulation path, and after the shell of the filter enters the working range of the spray gun 20, powder spraying operation is performed. When the external gear teeth of the support sleeve 19 of the carrier 16 are engaged with the gear teeth on the rack 21 of the active rotation assembly, the rack 21 can enter into a rapid translational movement, whenever the rack 21 establishes a connection with the carrier 16 and drives the housing of the filter on the carrier 16 to spin. Since the absolute value of the translational speed of the rack 21 is much larger than the absolute value of the translational speed of the carrier 16, that is, the housing of the filter, the carrier 16 is continuously driven by the rack 21 to rotate until the carrier 16 moves away from the movement range of the rack 21 and the rotation operation is stopped while the rack 21 and the carrier 16 can establish a connection. The housing of the filter, during the occurrence of spinning, passes just beyond the injection range intersection region of the spray gun 20. The spray gun 20 continuously sprays the molding powder toward the outer shell of the filter, and the sufficient amount of rotation ensures that the molding powder is uniformly coated on all parts of the outer shell surface of the filter. When the carrier 16 carries the filter housing away from the spray gun 20 intersection area, the filter housing has completed the spray molding operation.

In the process, the plastic powder recovery system is always in a working state, and the air draft unit 4 works, so that an environment with the pressure smaller than the external pressure can be established in the floor type negative pressure bin 1. In this way, the plastic powder that has spread in the floor negative pressure bin and has not adhered to the surface of the housing of the filter cannot flow to the outside of the floor negative pressure bin 1. The diffused plastic powder moves from bottom to top along with the airflow, and enters the steady flow conveying air duct 3 after passing through the air draft unit 4. Because the steady flow conveying air duct 3 is obliquely arranged, the airflow is in a climbing motion state in the steady flow conveying air duct 3. The air flow moves in the steady flow conveying air duct 3, the width of the interior of the steady flow conveying air duct 3 gradually increases along with the increase of the height, and the movement speed of the air flow is slowed down, so that coarse grain plastic powder diffused in the air descends under the influence of self gravity, the coarse grain plastic powder can fall in the area of the collecting channel 6, finally the coarse grain plastic powder falls into the coarse grain storage cavity 7, and then the plastic powder distributed in the air only remains fine plastic powder. The airflow climbs to the highest position and then enters the fine dust collector 9, and as the inner space of the fine dust collector 9 is larger and the inner surface of the fine dust collector 9 is larger, the fine plastic powder in the airflow is adhered and deposited in the fine dust storage cavity 10 in a state that the flow speed is slower; the air flow is discharged outwards after being filtered by the filter element 13. The plastic powder gathered in the coarse grain storage cavity 7 and the fine dust storage cavity 10 can be discharged outwards by opening a valve, so that the aim of reutilizing the plastic powder is fulfilled.

Claims

1. The utility model provides a filter spraying device, filter spraying device includes spraying system and molding powder recovery system, spraying system includes unidirectional transport subassembly (14), spray gun (20), unidirectional transport subassembly (14) are including conveying chain (15), carrier (16) are with rotation mode movable mounting on conveying chain (15) and equidistant are arranged on conveying chain (15), conveying chain (15) pass molding powder recovery system, spray gun (20) are located molding powder recovery system and spray range of spray gun (20) are towards carrier (16) on conveying chain (15), its characterized in that: the spraying system is characterized in that the side surface of the carrier (16) is provided with a transmission tooth, the spraying system is also provided with an active rotating assembly, the active rotating assembly comprises a linear cylinder and a rack (21), the rack (21) is fixedly connected with a piston rod of the linear cylinder, the direction of the movement of the rack (21) is parallel to the conveying direction of the unidirectional conveying assembly (14), the body of the rack (21) is protruded to one side, the transmission tooth is arranged at the protruded position of the rack (21), the movement range of the transmission tooth of the carrier (16) is intersected with the movement range of the transmission tooth of the rack (21), the carrier (16) and the rack (21) are movably connected through meshing of the transmission tooth, the spray guns (20) are distributed on two sides of a conveying chain (15) and are annularly distributed at equal angles in the same horizontal plane, the spraying range of the spray guns (20) is intersected in the same area and located in the movement range of the carrier (16), the powder recycling system comprises a floor type negative pressure bin (1), a conveying air duct (3), an air suction unit (4), a collector (5) and a coarse dust collector (9) are arranged in the floor type bin (2), the floor type negative pressure bin (1) is provided with a cavity (2), the movement range of the carrier (16) is intersected with the cavity (2), the parts of the spray gun (20) and the rack (21) provided with the transmission teeth are all positioned in the cavity (2), the exhaust unit (4) is arranged at the top end of the floor type negative pressure bin (1), the air inlet end of the exhaust unit (4) is communicated with the cavity (2), the steady flow conveying air duct (3) is of a straight tubular structure, the exhaust unit (4) is connected with one end of the steady flow conveying air duct (3), the air outlet end of the exhaust unit (4) is communicated with the inside of the steady flow conveying air duct (3), the other end of the steady flow conveying air duct (3) is connected with the fine dust collector (9), the steady flow conveying air duct (3) is obliquely arranged, the coarse grain collector (5) is arranged at the middle part of the steady flow conveying air duct (3), at least three collecting channels (6) are arranged at the top end of the coarse grain collector (5), the central lines of the collecting channels (6) are all positioned in the vertical direction, the collecting channels (6) are arranged at intervals and straightly along the steady flow conveying air duct (3), one ends of the collecting channels (6) are all positioned below the steady flow conveying air duct (3) and are communicated with the inside of the steady flow conveying air duct (3), coarse grain storage cavities (7) are arranged inside the coarse grain collector (5), the other ends of the collecting channels (6) are communicated with a coarse grain storage cavity (7), coarse grain discharge holes (8) are formed in the bottom ends of the coarse grain collectors (5), the coarse grain discharge holes (8) are communicated with the coarse grain storage cavity (7), valves are arranged on the coarse grain discharge holes (8) of the coarse grain collectors (5), fine dust storage cavities (10) are formed in the fine dust collectors (9), exhaust channels (11) are formed in the tops of the fine dust collectors (9), fine dust discharge holes (12) are formed in the bottoms of the fine dust collectors (9), the fine dust storage cavities (10) are communicated with the inside of the steady flow conveying air duct (3), the exhaust channel (11) and the fine dust discharging hole (12) are communicated with the fine dust storage cavity (10), a filter element (13) is arranged in the fine dust collector (9), the filter element (13) is arranged in the exhaust channel (11), a valve is arranged on the fine dust collector (9) at the fine dust discharging hole (12), the distribution length of transmission teeth on the rack (21) is more than three times of the distance between adjacent carriers (16), the annular distribution interval angle of the spray guns (20) is ninety degrees, the width of the end, which is communicated with the inside of the steady flow conveying air duct (3), on the collection channel (6) gradually becomes smaller in the upward-downward direction, the width of the inside of the steady flow conveying air duct (3) is gradually increased from bottom to top.