CN112980664A

CN112980664A - Automatic flat plate coating machine

Info

Publication number: CN112980664A
Application number: CN202110397874.5A
Authority: CN
Inventors: 李文强; 赵东; 王作鹏; 饶品凤
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-03-02
Filing date: 2021-04-14
Publication date: 2021-06-18

Abstract

The present invention relates to an automatic flat-plate coating machine, including a flat-plate loading rack (Fig. 2), a coating rack loading rack (Fig. 3), a main machine (reference numeral 31), a coating rack (Fig. 5), a flat-plate Conveying system (Fig. 4), coating rack conveying system, control system, coating rack locking device, automatic sterilizing device and other functional components, wherein the flat conveying system includes a flat conveying cabin and a hatch cover, and the flat conveying system has a vertical conveying flat plate , triple function of horizontal conveying flat plate and automatic coating. It has the characteristics of convenient operation, improved reliability of experimental data, fast speed, continuous operation, etc. It can be widely used in food and beverage, medicine, cosmetics, inspection institutions, and medical and health fields.

Description

Automatic flat plate coating machine

Technical Field

The invention relates to automatic flat plate coating machine equipment, which is mainly applied to the field of biology. The method is suitable for coating of clinical medical pathogenic microorganism samples, detecting the limit of microorganisms of foods, cosmetics and medicines, and further separating single bacterial colonies or counting viable bacteria of bacteria.

Background

The bacterial coating plate culture is a very common experiment in the field of biology, is mainly used for separating bacterial single colonies, counting the concentration of bacterial viable bacteria, and coating an inoculating loop commonly used in the plate coating process, and has the advantages of low speed, uneven coating and easy pollution, and is the most common problem in the experiment, and has higher requirement on the operating skill of an experimenter.

The invention aims to design automatic equipment, which can solve the problems and achieve the aims of high efficiency, uniform coating, difficult pollution, simple and convenient operation and low production cost.

The microbial coating is commonly used for detecting food, beverage, medicines and cosmetics, and the medical machine is used for clinical detection of pathogenic bacteria. The total number of bacteria is less than 100cfu/ml as indicated by the microbial limit of purified water in Chinese pharmacopoeia 2015 edition. Most of oral medicines such as medicaments, ointments, water aqua and the like have clear requirements on the total number of microorganisms and the number of specific microorganisms, in the field of food, the total number of bacteria and fungi is listed as a necessary item, the biological characteristics of food fermentation, such as beer, at different stages need to be monitored, and the microbial coating is also one of the commonly used methods.

And according to the relevant industry standard and the characteristics of flat plate coating, the volume of a coated sample is generally more than 0.2ml and less than 1 ml. The standard coating volume for this equipment design is therefore 1ml maximum.

Disclosure of Invention

The invention relates to an automatic coating machine, which comprises a flat plate loading frame (figure 2), a coating frame loading frame (figure 3), a host machine shell (reference numeral 31), a coating frame (figure 5), a flat plate conveying system (figure 4), a coating frame conveying system, a control system and the like. The device has the characteristics of simple and quick operation, simple structure and low cost.

The invention designs a plate loading frame (figure 2) which consists of a plate loading cabin (reference numeral 11) and a chassis (reference numeral 14), and can conveniently place a plate with an inner package and a culture medium added in the plate loading cabin (reference numeral 11). Inverting the culture medium plate completely packaged, cutting open the bottom seal of the plate inner packaging bag, inserting the plate loading cabin into the packaging bag, inverting the loading frame, pushing the loading frame into a host machine plate inlet (reference numeral 5), fixing the plate loading frame at a constant position through a chassis (reference numeral 14), and enabling the plate to freely slide up and down in the loading cabin (reference numeral 11). The plate loading frame has the following characteristics: the diameter of the inner diameter or the inscribed circle of the fixing rod (12) of the flat loading cabin (11) is more than 0.2mm larger than the outer diameter of the upper shell of the flat used, and the diameter of the outer diameter or the inscribed circle of the fixing rod (12) of the lower end of the flat loading cabin (11) or the inscribed circle of the fixing rod (12) is more than 0.2mm smaller than the diameter of the flat inlet (5) of the host (31); the lower end of the plate loading frame is provided with a chassis (reference numeral 14), the chassis (reference numeral 14) is annular, the outer diameter is larger than the outer diameter of a plate inlet (reference numeral 5) of a host (reference numeral 31), and the inner diameter is not smaller than the inner diameter of a plate loading cabin or the diameter of an inscribed circle of a fixing rod (reference numeral 12).

The invention relates to a coating rack loading rack and a coating rack loading groove device, wherein the coating rack loading rack has similar functions with a flat plate loading rack and comprises a coating rack loading cabin (reference numeral 15) and a chassis (reference numeral 18). Coating frame loading groove device, the design is on host computer top right side, loading groove both sides (reference numeral 13) inboard distance is 82mm, be greater than the coating frame total length, the height design is 12mm, it is equivalent with the width of coating frame locating arm, design two bosss (reference numeral 16) in loading groove both sides, make the coating frame of packing accurately confirm to be located the loading groove, can make coating arm and loading groove bottom form certain clearance simultaneously, cut coating frame wrapping bag bottom and seal, insert the wrapping bag to the coating frame loading frame, make dead lever (reference numeral 17) follow the clearance passes, make the coating frame fix in the coating frame loading frame, can freely slide from top to bottom, but can not overturn or around or move, make the coating frame wrapping bag cover outside the coating frame loading frame simultaneously, play sealed pollution prevention's effect. Then the loading frame loaded with the coating frame is placed at the inlet position of the coating frame of the host machine and fixed.

The invention designs a flat plate conveying system which comprises a flat plate conveying cabin (reference numeral 19), a flat plate fixing disc (reference numeral 21), a bracket (reference numeral 25) and an electric push rod.

The flat plate conveying cabin (reference numeral 19) comprises a cabin body and a cabin cover (reference numeral 23), the cabin body plays a role of transporting flat plates left and right, meanwhile, a supporting platform is provided for transporting the flat plates up and down, and the cabin cover (reference numeral 23) plays a role of fixing a flat plate (reference numeral 21) for conveying the flat plates up and down. The flat plate conveying cabin body and the movable cabin cover (reference numeral 23) are characterized in that the cabin body is provided with a groove or a convex edge (reference numeral 20) which is matched with the convex edge or the groove (reference numeral 24) on the cabin cover (reference numeral 23), and the cabin cover (reference numeral 23) can slide in the cabin body under the driving of a motor and a screw rod. In order to achieve the functions of claim 4 and claim 10, the invention provides a flat plate conveying cabin cover (reference numeral 23), wherein structures such as a flat plate fixing disc driving motor fixing groove (reference numeral 32), a flat plate support driving motor fixing groove (reference numeral 34), a flat plate support fixing groove (reference numeral 33), a wire hole (reference numeral 35) and the like are designed for wire transmission.

The flat fixed disc (reference numeral 21) is connected with a motor output shaft fixed on the hatch (reference numeral 23) and can rotate under the drive of the motor to finish coating. The flat plate fixing frame is characterized in that the inner diameter of the upper opening of the flat plate fixing disc (reference numeral 21) is larger than the outer diameter of the lower flat plate shell, so that the lower flat plate shell can be fixed on the flat plate fixing disc (reference numeral 21), the lower surface of the flat plate fixing disc (reference numeral 21) is connected with a motor output shaft and can drive the flat plate fixing disc (reference numeral 21) and a flat plate to rotate together, and holes (reference numeral 22) are formed in the lower surface of the flat plate fixing frame.

And a bracket (reference numeral 25) is further designed in the plate conveying bin, and when the plate is coated, the bracket (reference numeral 25) can move downwards to support the cabin cover (reference numeral 23) so that the plate contacts the coating rack. When the flat plate is taken out, the bracket (reference numeral 25) can also move upwards to penetrate through the hole (reference numeral 22) below the flat plate fixed disc (reference numeral 21), and after the lower shell and the upper shell of the flat plate are supported to be closed, the flat plate is taken out, so that the contact between the flat plate and the outside is reduced, and the pollution is reduced. The support (reference numeral 25) has the following features: the bracket (reference numeral 25) is connected with a motor, the bracket (reference numeral 25) can be lifted, the bracket (reference numeral 25) is lifted, the flat plate can be supported through the hole (reference numeral 22) on the flat plate fixing disc (reference numeral 21), and when the bracket (reference numeral 25) is lowered, the hatch cover (reference numeral 23) of claim 4 can be supported to drive the flat plate fixing frame and the flat plate to ascend.

The invention designs a coating frame which can uniformly coat a sample on a flat plate and has the following characteristics that the coating frame consists of three parts, namely a sample adding port (reference numeral 7), a positioning arm (reference numeral 27) and a coating arm (reference numeral 28); the positioning arm (reference numeral 27) is of a T-shaped structure and is positioned at the upper end of the sample adding port (reference numeral 7); with this structure, the coating rack is suspended on the conveyor belt, and the conveyance of the coating rack is realized. The upper end of the coating arm (reference numeral 28) is provided with a groove (reference numeral 29) which is communicated with the sample adding port (reference numeral 26) of the coating frame, the volume of the groove (reference numeral 29) is more than 1ml, the coating surface at the lowest part of the coating arm (reference numeral 28) is in a circular arc shape, the bottom of the groove (reference numeral 29) is provided with a slit (reference numeral 30), the intersection line of the slit (reference numeral 30) and the bottom of the coating arm (reference numeral 28) can be controlled by controlling the height of the intersection line and the thickness of the coating layer, a sample flows into the groove (reference numeral 29) of the coating arm (reference numeral 28) through the sample adding port (reference numeral 26) of the coating frame and is uniformly coated on a flat plate through the slit (reference numeral 30), and the thickness of the coating layer can be controlled by controlling the height difference of the.

The invention designs a coating rack conveying system which comprises two conveying belts, wherein a coating arm (reference numeral 28) can pass through a space between the two conveying belts, and a coating rack is hung on the conveying belts through a positioning arm (reference numeral 27) and conveyed to a coating position to stop. After coating is completed, the conveyor belt continues to run to transport the coating rack out of the facility. Then, a new coating frame is replaced to repeat the actions, so that the mutual cross contamination is avoided. The conveyor system has the feature that the conveyor belt pitch is greater than the width of the coating arm (reference numeral 28) and less than the width of the positioning arm (reference numeral 27). The conveyor belt is designed to be wider at the inlet of the coating stand (reference numeral 6) than at the outlet of the coating stand (reference numeral 9), gradually tightening up the coating stand. The coating rack can move along the direction of the conveyor belt, can also move up and down in the gap of the conveyor belt, but can not move along other directions. Therefore, the coating frame can avoid scratching the flat plate due to the uneven flat plate in the coating process. Meanwhile, in order to ensure that the coating rack is not blocked when falling into the coating rack conveying system and the coating rack reaches the coating position, the coating rack is tightly fixed through the conveying system and cannot be conveyed out of the equipment at the outlet position due to the blocking of the garbage bag.

The invention also designs a coating rack locking device which is positioned below the inlet (reference number 6) of the coating rack and above the conveyor belt, when the locking device is opened, the lowermost coating rack enters the coating rack conveying system, and the last coating rack can be locked to avoid mutual influence.

The invention also designs a set of control system which controls the operation of each part through circuit design and internal programs. After a user respectively loads a flat plate and a coating rack (generally, 10 bags are arranged in the flat plate loading rack and the coating rack loading rack) into the corresponding flat plate loading rack and the coating rack loading rack, the flat plate loading rack and the coating rack are placed into a flat plate inlet (reference numeral 5) and a coating rack inlet (reference numeral 6) corresponding to a host (reference numeral 31), the user presses a start-stop (reference numeral 2) button, the equipment starts to operate, the sample is added after the user hears a prompt tone, the user adds a sample, presses a completion key (reference numeral 4), the equipment finishes coating, the corresponding coating rack and the flat plate are conveyed out of the equipment, then a new set is conveyed, the user hears the prompt tone to add the sample again, presses a completion key (reference numeral 4), the user presses the start-stop key (reference numeral 2) after all samples are added, the program automatically finishes coating, the flat plate and the coating rack are conveyed out of the equipment, and the program ends. In the operation process, the operation positions of the flat plate conveying cabin (reference numeral 19), the cabin cover (reference numeral 23), the support frame, the flat plate fixing disc (reference numeral 21) and the coating frame conveying belt need to be accurately controlled, corresponding parts are provided with position switches, and the position switches of all parts realize the position control of the corresponding parts.

The invention also designs a set of push rod control system which is positioned at one side of the flat plate and is opposite to the position of the flat plate outlet (reference numeral 10), when the flat plate returns to the initial position after coating, the lower flat plate shell is supported to the position of the flat plate outlet (reference numeral 10) by the supporting rod and is combined with the upper cover, at the moment, the push rod is started, so that the flat plate is ejected out from the plate outlet, and the upper and lower flat plate shells are well covered, thereby avoiding pollution.

The invention designs an intermediate platform, which is positioned about 25mm below a flat plate inlet (reference numeral 5) of a host machine, so that the height of the upper surface of the platform is not lower than the height of the lower edge of a flat plate outlet (reference numeral 10), the platform is provided with a round hole, the diameter of the round hole is larger than the outer diameter of a lower flat plate shell and smaller than the outer diameter of an upper flat plate shell, and the round hole is concentric with the flat plate inlet (reference numeral 5) of the host machine. After entering the apparatus through the inlet (reference numeral 5), the plate falls on the platform, as the plate moves further downward, the upper shell of the plate is stopped on the platform, so that the upper shell and the lower shell can be separated, and after coating is completed, the lower shell returns to the position to be combined with the upper shell, and then the plate is sent out of the apparatus through the outlet (reference numeral 10).

The invention also designs a retractable cover plate (reference numeral 8) above the sample adding port (reference numeral 7), when the operation is started, the cover plate (reference numeral 8) is pulled out, the special coating rack collecting bag is hung on the cover plate (reference numeral 8), and the coating rack automatically falls into the mobile phone credit to avoid polluting the environment.

The invention designs a foot switch (reference numeral 3) device which can replace a completion button and is convenient for a user to operate.

The automatic flat plate coating equipment designed by the invention has the advantages of simple operation, automatic disinfection function and automatic shutdown function. The user opens the power key, prepares to accomplish, presses and stops (reference numeral 2) button, and equipment begins to operate, after hearing the prompt tone, adds 1ml sample that awaits measuring to sample addition port (reference numeral 7), presses and accomplishes key (reference numeral 4), and all operations are accomplished automatically to equipment, hear the prompt tone again, and the sample is added again, circulates in proper order. After all the operations are finished, a start-stop key (reference numeral 2) is pressed, and after the equipment runs, a disinfection program is started, and the equipment is automatically shut down. The average time for coating one flat plate is only 3 to 4 seconds on average, so that the working efficiency is greatly improved. The equipment is also provided with an ozone disinfection system, all the operations are performed in a relatively sealed environment, the pollution of microorganisms can be avoided to the greatest extent, the operation is performed by one key, and after the disinfection is completed, the system automatically turns off the power supply without waiting.

Drawings

FIG. 1 shows a host housing

FIG. 2 is a plate loading frame

FIG. 3 shows a coating rack loading rack

FIG. 4 shows a plate conveyer

FIG. 5 shows a coating rack

FIG. 6 is a conveying hatch cover

FIG. 7 shows the whole machine

The figures are labeled as follows: 1. a power switch; 2. a start-stop key; 3. a foot switch interface; 4. a completion key; 5. a plate inlet; 6. a coating rack inlet; 7, a sample loading port; 8, a retractable cover plate; 9. a coating rack outlet; 10. a flat plate outlet; 11. a plate loading bay; 12. a plate loading frame fixing rod; 13. the coating frame is provided with a groove edge; 14. a plate carrier chassis; 15. a coating rack loading bay; 16. a coating rack loading slot boss; 17. a coating rack loading rack fixing rod; 18. a coating rack carrier chassis; 19 a flat plate conveying cabin; 20. a convex edge; 21. a flat plate fixing disc; 22. an aperture; 23. a flat plate transport hatch; 24. a groove; 25. a support; 26. a sample port of the coating frame; 27. a positioning arm; 28. a coating arm; 29. a groove; 30. sewing; 31 a host housing; 32. a motor fixing groove of a flat plate fixing disc; 33. a flat plate bracket fixing groove; the flat plate support drives a motor fixing groove; 35 line holes.

Detailed Description

1 mounting of the plates

Placing the well-packed flat plates (10 bags) on an operation table, inverting, keeping the cover downward, keeping one surface of the culture medium upward, and placing the flat plates orderly to avoid toppling; the bag is cut open along the seal, the plate carrier chassis (reference numeral 14) is held in hand, and the plate carrier is inserted into the bag while the plate is loaded into the plate in the chamber. After the packaging bag is inserted to the bottom, a finger is placed in the middle of the bottom plate, the other hand holds the packaging bag and the lower end of the loading cabin or the fixed rod (reference numeral 12), the packaging bag and the lower end of the fixed rod are inclined at a certain angle, the finger is pressed onto the bottom flat plate, the flat plate loading frame is turned over, and the flat plate loading frame is placed on the host (reference numeral 31). The plate carrier is pushed into the plate entrance (reference numeral 5) of the host (reference numeral 31).

2. Coating rack mounting

The coating rack (10 bags in each bag) with intact inner package is laid flat and put into a loading groove of the coating rack, attention is paid to ensure that the lower end of the coating rack faces to the left towards a right positioning arm, the coating rack is cut off along a right sealing position by scissors, a base is loaded on the coating rack by holding, a rack fixing rod (reference numeral 17) is inserted into a packaging bag, the top end of the fixing rod (reference numeral 17) is inserted into a gap between the coating rack and the bottom of the fixing groove, the coating rack loading rack is pushed leftwards by the right hand, a packaging bag of the coating rack is held by the left hand, the coating rack positioning arm is fixed between the fixing rods (reference numeral 17), the coating rack is completely loaded in a cabin, and meanwhile, the packaging bag is sleeved outside the coating rack loading rack to play a. The lower opening of the bottom plate of the coating rack loading frame is blocked by hand, the base of the coating rack loading frame is downward and is placed on a main machine (reference numeral 31). The coating rack carrier is pushed into the host computer (reference numeral 31) into the coating rack entrance (reference numeral 6).

3. The system starts to operate

When a button of a start-stop (reference numeral 2) is pressed, a support (reference numeral 25) in the flat plate conveying cabin (reference numeral 19) descends by about 15mm, the upper shell of the flat plate is left on a platform at the position of a flat plate outlet (reference numeral 10), and the lower shell of the flat plate descends into the flat plate conveying cabin (reference numeral 19) along with the flat plate support frame.

The coating rack locking device is automatically switched on, the coating rack falls on the coating rack conveyor belt, the coating rack is conveyed forwards by 150mm, and the coating rack is stopped at the coating position.

The flat plate transport chamber (reference numeral 19) moves 150mm as a whole, reaches the coating position, and stops.

The plate holder continues to move 20mm downward, raising the hatch (23) by about 15mm, bringing the plate medium and the spreader into contact.

The device sends out a prompt tone to indicate that the preparation is finished and the sample can be added.

The user adds 1ml of sample from the sample addition port (reference numeral 7), and the sample flows into the coating arm slot along the sample addition port, and then presses the completion key (reference numeral 4) or depresses the foot switch (reference numeral 3).

The flat fixed disk (reference numeral 21) rotates for 2-3 circles. So that the sample in the coating arm groove is uniformly coated on the plate culture medium.

The plate support moves up 20mm and the hatch (reference numeral 23) is lowered.

The coating-stand conveyor belt continues to run forward for 2 seconds and the coating stand is conveyed out of the coating-stand outlet (reference numeral 9).

The plate conveying cabin (reference numeral 19) returns to the initial position, the plate supporting frame continues to move upwards for 20mm, the lower shell of the plate is supported to the position of the plate outlet (reference numeral 10), and the upper shell and the lower shell of the plate are combined together.

The electric push rod is activated to push the coated plate out to the plate outlet (reference numeral 10).

And taking out the flat plate, automatically entering the next hiking program by the equipment, and repeatedly executing the steps.

If the user finishes making one sample and does not make the next sample, after the user finishes adding the sample, the start-stop key (pop-up) is pressed again (reference numeral 2), the device finishes coating automatically, and the coating rack and the flat plate are conveyed out of the device.

The apparatus automatically performs a disinfection program. After the disinfection is finished, the power supply is automatically turned off.

The device is used for coating microorganisms, 10 samples are coated, the total time is less than 2 minutes, and the efficiency is improved by more than 5 times compared with the manual coating efficiency. The coating is uniform, and the coating area accounts for more than 90% of the whole plate area. The coating uniformity is higher than manual coating. It is also very convenient to install the plate and the coating stand, for a total time not exceeding 1 minute.

Claims

1. an automatic flat coating machine, it is characterized in that described automatic flat coating machine comprises flat loading rack, coating rack loading rack, host shell, coating rack, flat conveying system, coating rack conveying system, control system , intermediate platform, coating rack locking device, coating rack loading slot, disinfection components and other functional components.

2. The flat loading rack according to claim 1, characterized in that the flat loading rack comprises a chassis and a flat loading compartment, and the flat loading compartment is a circular space or a space composed of more than 3 fixed rods, and the flat loading The inner diameter of the cabin or the diameter of the inscribed circle of the fixing rod is more than 0.2mm larger than the outer diameter of the medium plate cover used, and the outer diameter of the bottom end of the loading tank or the outer diameter of the inscribed circle of the fixing rod is more than 0.2mm smaller than the diameter of the entrance of the main engine plate; the outer diameter of the chassis is larger than that of the main engine The diameter of the entrance of the plate shall not be less than the inner diameter of the loading compartment or the diameter of the inscribed circle of the fixing rod.

3. The coating rack loading rack according to claim 1 is characterized in that the coating rack loading rack comprises a coating rack loading compartment and a chassis; the coating rack loading compartment is composed of more than 4 fixing rods, and The cloth rack can be fixed in the loading compartment of the coating rack through the fixing rod, and can only slide up and down in the loading compartment of the coating rack; the size of the chassis is larger than the size of the entrance of the main coating rack, and it is fixed with the fixing rod; the coating The rack fixing rod at the lower end of the chassis can penetrate deep into the inlet of the main machine coating rack to match it, so that the coating rack loading rack is fixed at the inlet position of the main machine coating rack.

4. The flat conveying system according to claim 1, characterized in that the flat conveying system has triple functions of conveying the flat up and down, conveying the flat left and right, and driving the flat to rotate, the flat conveying system comprises a flat conveying cabin, and the flat is fixed. The plate is composed of a tray, a bracket and an electric push rod; the flat conveying cabin is composed of a cabin body and a movable hatch cover. The hatch cover can slide in the cabin, and the conveying cabin has wire holes, which can drive the conveying cabin to move left and right; the flat plate fixing plate is connected with the motor output shaft, which can drive the plate fixing plate and the plate to rotate, and the plate fixing plate has holes below; The bracket can be driven up or down by a motor. When the bracket is raised, the plate can be supported through the hole on the plate fixing plate. When the bracket is lowered, the hatch cover is supported to drive the plate fixing plate to rise; The electric push rod is used to send the coated flat plate out of the equipment.

5. The coating rack according to claim 1 is characterized in that the coating rack comprises a sample feeding port, a positioning arm, and a coating arm consisting of three parts; the positioning arm is a T-shaped structure and is located at the top of the coating rack There is a groove on the top of the coating arm, which is communicated with the sample feeding port, the volume of the groove is greater than 1ml, and there is a slit at the bottom of each coating arm that communicates with the groove on the coating arm.

6. The coating rack conveying system according to claim 1, wherein the coating rack conveying system is composed of two conveyor belts, and the distance between the conveyor belts is greater than the width of the coating arms in the coating rack, and Less than the width of the positioning arm in the coater.

7. The control system according to claim 1, characterized in that the control system comprises a sample adding finish and a start-stop button, a flat conveying cabin, a hatch cover, a support frame, a flat plate fixing plate and a coating rack conveying respectively Equipped with a positioning switch, it can accurately control the position of the flat conveying cabin, the hatch cover, the support frame, the flat plate fixing plate and the coating frame; the sample addition and start and stop buttons are used to control the coating operation.

8. The middle platform according to claim 1, wherein the middle platform is located at the outlet of the flat plate, and there is a circular hole on the platform, the diameter of which is larger than the outer diameter of the lower shell of the flat plate and smaller than the outer diameter of the upper shell of the flat plate. The entrance of the host plate is concentric with the circle.

9. The coating rack locking device according to claim 1, characterized in that it has the function of locking and separating the coating rack, and is located below the entrance of the coating rack. When the flat plate starts to be transported, the locking device is opened, and the coating rack is unlocked and enters the conveyance. system, and then the locking device snaps shut, locking the latter coater from the previous coater.

10. The coating rack loading slot according to claim 1, wherein the width of both sides of the coating rack loading slot is greater than the width of the coating rack, and there is more than one boss inside the loading slot, and the boss is different from the width of the coating rack. The two sides are parallel, and the height of the boss is less than the height of the two sides.