WO2021190100A1

WO2021190100A1 - Powder recovery and separation mechanism, system, and method for use in high-temperature environment

Info

Publication number: WO2021190100A1
Application number: PCT/CN2021/071509
Authority: WO
Inventors: 王黎明; 冉学举; 李燕乐; 李方义; 鹿海洋; 杜际雨; 张兴艺; 戚小霞
Original assignee: 山东大学
Priority date: 2020-03-26
Filing date: 2021-01-13
Publication date: 2021-09-30
Also published as: CN111282387A; CN111282387B

Abstract

The present invention relates to the technical field of powder spray coating. Disclosed are a powder recovery and separation mechanism, system, and method for use in a high-temperature environment. The mechanism comprises a housing and a mesh screen mechanism disposed in the housing, the mesh screen mechanism is connected to a power source, and the power source can drive the mesh screen mechanism to rotate, so as to centrifuge powder attached to the mesh screen mechanism. The present invention can effectively increase the powder utilization rate, and reduce the powder diffusion risk, and can be applied to various environments and working conditions.

Description

Powder recovery and separation mechanism, system and method used in high temperature environment

Technical field

The invention relates to the technical field of powder spraying, in particular to a powder recovery and separation mechanism, system and method used in a high-temperature environment.

Background technique

The statements here only provide background art related to the present invention, and do not necessarily constitute prior art.

Thermal spraying is the process of heating powdered materials into a molten or semi-molten state and spraying them onto the surface of the workpiece to be repaired by high-speed airflow to form a dense functional coating. It is often used to repair or improve the surface performance of key components. However, the actual spraying conditions are complex and diverse. The sprayed powder cannot be fully melted in the flame flow and cannot be deposited on the surface to be repaired. High-speed shooting powder particles often collide with each other in a complex gas field and deviate from the original direction, melting the powder particles. High-speed impact on the surface to be repaired will cause spattering and cause part of the powder to be lost; while spraying, it will often cause great dust pollution, especially when spraying metal powder; therefore, the existing powder spraying technology has two defects ①The powder utilization rate of thermal spraying technology is low; ②It is easy to cause metal particles to be dispersed in the air, which can cause metal poisoning when inhaled into the human body, and pollute the surrounding environment when discharged into the atmosphere. Therefore, it is particularly important for the recovery and separation of powder in thermal spraying work.

The inventor found that the existing recycling methods are mainly for powders at room temperature. Filters are often used when filtering powders. It is easy to block the filter after long-term use, and it is impossible to easily recover the residues in the filter and replace the filter. , And the recovery method is only for one kind of powder recovery and separation device, which cannot be used in a working environment where there are multiple powder mixtures.

Summary of the invention

In view of the shortcomings of the powder spraying recovery and separation process in the prior art, the purpose of the present invention is to provide a powder recovery and separation mechanism, system and method used in a high-temperature environment, which can effectively improve the powder utilization rate and reduce the risk of powder diffusion. It can be applied to a variety of environments and working conditions.

In order to achieve the above objectives, the present invention is achieved through the following technical solutions:

In the first aspect, the present invention proposes a powder recovery and separation mechanism for high temperature environments, including a box body and a mesh screen mechanism arranged inside the box body. The mesh screen mechanism is connected to a power source, and the power source can drive the mesh screen mechanism to rotate. Thus, the powder attached to the screen mechanism is centrifuged.

As a further technical solution, the mesh screen mechanism includes a plurality of single mesh screens arranged in parallel, and each single mesh screen is connected to a power source.

As a further technical solution, each of the single mesh screens has a circular shape, and the periphery of each single mesh screen is provided with gear teeth for engaging a power source.

As a further technical solution, each single mesh screen includes a first ring member, a second ring member and a screen mesh, the first ring member and the second ring member are buckled together, and the screen mesh is installed on the first ring member.

As a further technical solution, the first ring member includes a first frame body having an annular shape, an annular collection groove is opened in the first frame body, and an annular sliding groove is formed on both the top side and the bottom side of the first frame; Gear teeth are arranged on the periphery of a frame body, and the gear teeth can drive the first ring member to perform centrifugal movement by meshing with the power source; the first frame body also has a groove-shaped structure for installing a screen.

As a further technical solution, the second ring member includes a second frame body in a ring shape, a spherical joint is provided on one side of the second frame body, and the joint can be connected to the top side and/or bottom of the first frame body. On the side, the second frame body is positioned by the spherical joint and the annular slide groove; the other side of the second frame body is provided with a plurality of springs, the springs are connected to the box body, and a certain pre-tensioning force is provided to fix the net through the springs. The screen mechanism facilitates the clamping and removal of the screen.

In the second aspect, the present invention proposes a powder recovery and separation system for use in a high temperature environment, which includes an air collection box, a negative pressure source, a cooling mechanism, the recovery and separation mechanism as described in the first aspect, a waste water tank, and an air collection box. The top side of the gas collecting port is connected with a funnel-shaped gas collecting port, the gas collecting box is also connected with the negative pressure source and the cooling mechanism, the cooling mechanism is connected with the recovery and separation mechanism, and the recovery and separation mechanism is connected with the negative pressure source and the waste water tank.

As a further technical solution, the negative pressure source includes a first negative pressure source and a second negative pressure source, the first negative pressure source is connected to the air collecting box, and the second negative pressure source is connected to the recovery and separation mechanism. The first negative pressure source and the second negative pressure source can be independently switched on and off respectively.

As a further technical solution, the cooling mechanism includes a cooling box and a cooling fan connected above the cooling box; the left side of the cooling box is provided with a water injection port and a water outlet, and a cooling pipe is installed on the bottom side of the cooling box to cool The left side of the box is also provided with an observation window; the front and rear sides of the cooling box are equipped with ventilation windows, and the cooling box is also connected to a recovery and separation mechanism.

As a further technical solution, the box of the recovery and separation mechanism is connected to the cooling mechanism.

As a further technical solution, the box body of the powder and particle recovery mechanism is also connected to a waste water tank.

In the third aspect, the present invention also provides a powder recovery and separation method, using the powder recovery and separation system used in a high temperature environment as described in the second aspect, including the following steps:

Start the first negative pressure source;

The powder enters the air collecting box through the collection port, and then enters the cooling box for cooling;

After the powder is cooled in the cooling box, it enters the recovery and separation mechanism for dust filtration;

In the recovery and separation mechanism, when an abnormality in powder recovery and separation is found, the second negative pressure source is turned on, and the negative pressure value of the second negative pressure source is set to be smaller than the first negative pressure source, so that the gas in the box of the powder recovery and separation mechanism Flow from bottom to top, thereby blowing up the powder stuck in the screen, and collecting the powder in the collection tank in time through the centrifugal action of the screen mechanism.

The abnormality of powder recovery and separation is the case where the powder is stuck in the gap in the screen and cannot be collected in the collection tank by centrifugation.

The beneficial effects of the above-mentioned embodiments of the present invention are as follows:

1. The technical solution disclosed in the present invention achieves the purpose of recovering and separating dust in a high-temperature environment. The powder is cooled by a cooling box, which prevents the powder particles at high temperature from adhering to the inner wall of the pipe or the gap of the filter, causing powder Incomplete recovery and clogged filter.

2. The technical scheme disclosed in the present invention designs a multi-stage recovery and separation device for mixing multiple powders, which can fully separate powder particles of different particle sizes.

3. The technical scheme disclosed in the present invention uses a back-blowing device to avoid powder particles from clogging the filter screen, and at the same time uses a centrifugal device to further recover the powder in the filter screen, and a slot-type filter screen device can be used to quickly and easily recover the filter screen. Powder particles.

Description of the drawings

The drawings of the specification forming a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention.

FIG. 1 is a schematic diagram of the overall structure of one or more embodiments of the present invention,

Figure 2a is a schematic front side view of the cooling mechanism structure of one or more embodiments of the present invention,

Fig. 2b is a schematic view of the left side of the cooling mechanism structure of one or more embodiments of the present invention,

Fig. 3 is a schematic diagram of the cooling pipe structure of one or more embodiments of the present invention,

4 is a side view of the recovery and separation mechanism of one or more embodiments of the present invention,

Figure 5 is a schematic diagram of a single mesh screen according to one or more embodiments of the present invention,

Fig. 6a is a schematic top view of a first ring member of one or more embodiments of the present invention,

Fig. 6b is a cross-sectional view of the first ring member of one or more embodiments of the present invention taken along line A-A in Fig. 5a,

Figure 6c is an elevation view of the first ring member of one or more embodiments of the present invention,

Fig. 7 is a schematic diagram of a second ring member of one or more embodiments of the present invention,

Figure 8a is a front view of the recovery and separation mechanism of one or more embodiments of the present invention,

Fig. 8b is a schematic diagram of the mesh screen and pinion assembly cut along D-D in Fig. 7a according to one or more embodiments of the present invention.

Among them, 1. Air collecting box, 2. Air collecting port, 3. First pipe, 4. Cooling mechanism, 41. Cooling box, 42. Ventilation window, 43. First air inlet, 44. Second air outlet , 45. Cooling fan, 46. Observation window, 47. Water injection port, 48. Water outlet, 49. Cooling pipe, 5. Second pipe, 6. Recovery and separation mechanism, 601. Second air inlet, 602. Recovery and separation The box body of the mechanism, 603. Mesh sealing cover, 604. Fixed table, 605. Fixed pillar, 606. Third air outlet, 607. Motor, 608. Gear bushing, 609. Straight connecting rod, 610. Pinion, 611. Single mesh screen, 612. Spherical joint, 613. Second ring, 614. Spring, 615. Screen, 616. Chute, 617. Collection trough, 618. Gear teeth, 619. First ring, 7. Waste water tank, 8. Magnetic control switch, 9. The third pipe, 10. The second fan, 11. The first fan.

In order to show the position of each part, the distance or size between each other is exaggerated, and the schematic diagram is only for illustration.

Detailed ways

It should be noted that the following detailed descriptions are all illustrative and are intended to provide further descriptions of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

It should be noted that the terms used here are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the present invention clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and/or "including" are used in this specification, they Indicate the existence of features, steps, operations, devices, components, and/or combinations thereof;

For the convenience of description, if the words "up", "down", "left", and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left, and right directions of the drawings themselves, and do not limit the structure. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

Term explanation part: The terms "installed", "connected", "connected", "fixed" and other terms in the present invention should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or a whole; It can be a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium, an internal connection between two components, or an interaction relationship between two components. For those of ordinary skill in the art The specific meaning of the above terms in the present invention can be understood according to the specific situation.

As described in the background art, in view of the shortcomings of the recovery and separation process in powder spraying in the prior art, the purpose of the present invention is to provide a powder recovery and separation mechanism, system and method used in a high-temperature environment, which can effectively improve powder utilization. At the same time, it can reduce the risk of powder diffusion. It can be applied to a variety of environments and working conditions. It will be described with reference to the embodiments and drawings.

Example 1

In a typical embodiment of the present invention, as shown in Figures 4 to 7b, a powder recovery and separation mechanism 6 used in a high temperature environment includes a box body and a mesh screen mechanism arranged inside the box body. The mechanism is connected with a power source, and the power source can drive the mesh-screen mechanism to rotate, thereby centrifuging the powder attached to the mesh-screen mechanism.

It can be understood that the power source in this embodiment selects a motor 607, and the motor 607 is connected to a gear sleeve 608, and the gear sleeve 608 is provided with a plurality of pinions 610 to engage and drive the mesh screen mechanism.

The mesh screen mechanism includes a plurality of single mesh screens 611 arranged in parallel, and each single mesh screen 611 is connected to a power source.

Each single mesh screen 611 has a circular shape, and gear teeth 618 are provided on the periphery of each single mesh screen 611. Each single mesh screen 611 includes a first ring 619, a second ring 613, and a screen 615. The first ring 619 and the second ring 613 are buckled together, and the screen 615 is installed on the first ring 619. The first ring member 619 includes a first frame body in a circular ring shape. The first frame body has a groove-shaped structure for installing a screen, and the screen is installed in the groove-shaped structure; the first frame body also has a ring-shaped collector It can be understood that the groove-shaped structure and the annular collecting groove 617 are connected; the top and bottom sides of the first frame are provided with annular slide grooves 616; the periphery of the first frame is provided with gear teeth 618, The teeth 618 can drive the first ring member 619 to perform centrifugal movement by meshing with the power source.

The second ring member 613 includes a second frame body having a ring shape. One side of the second frame body is provided with a spherical joint. The joint can be connected to the top side and/or bottom side of the first frame. The body is positioned through the spherical joint 612 and the annular slide groove 616 to achieve positioning; the other side of the second frame body is provided with a plurality of springs 614, the springs 614 are connected to the box, and the springs 614 provide a certain pretension to fix the net. The screen mechanism facilitates the clamping and removal of the screen.

It can be understood that, in order to achieve multi-stage filtration, the meshes of the screens 615 installed in each single mesh screen 611 are different. In this embodiment, the screens 615 of the single mesh screens 611 are arranged from top to bottom. The mesh number is arranged from small to large.

It can be understood that, in this embodiment, in order to fix each single mesh screen 611 in the box body, the box body is provided with an outward protrusion as the mesh screen sealing cover 603 where the single mesh screen 611 is installed.

It can be understood that when a plurality of single mesh screens 611 are arranged from top to bottom, the spring 614 of each single mesh screen 611 can touch the mesh sealing cover 603, thereby playing a fixed clamping role.

Example 2

In a typical implementation of the present invention, as shown in Figures 1 to 7b, a powder recovery and separation device used in a high temperature environment includes a gas collecting box 1, and the top surface of the gas collecting box 1 is connected in a funnel shape. The right side of the gas collecting box 1 is connected to the first fan 11 that provides negative pressure, the rear side of the gas collecting box 1 is provided with a first air outlet, and the first air outlet of the gas collecting box 1 is connected to the first air outlet. The pipe 3 is connected to the first air inlet 43 of the cooling mechanism 4 through the first pipe 3; the cooling mechanism 4 is also provided with a second air outlet 44, and the second air outlet 44 of the cooling mechanism 4 is connected to the second pipe 5 through the first pipe 3. The second pipe 5 is connected to the second air inlet 601 of the recovery and separation mechanism 6; the recovery and separation mechanism 6 is also provided with a third air outlet 606, and the third air outlet 606 of the recovery and separation mechanism 6 is connected to the third pipe 9 through the third pipe 9. The second fan 10 with a reverse blowing effect is connected, and the third air inlet of the waste water tank 7 is connected through a third pipe 9. The third air inlet of the waste water tank 7 is provided with a magnetic control switch 8 that controls the flow of the pipe. After the first fan 11 is started, a negative pressure is formed in the gas collecting box 1, and the gas mixed with powder is sucked in from the gas collecting port 2, and the gas is delivered to the cooling through the first air outlet on the rear side of the gas collecting box 1 and connected to the first pipe 3 Institution 4.

The cooling mechanism 4 includes a cooling box 41 and a cooling fan 45 connected above the cooling box 41 to cool the water in the cooling box 41 by air cooling; a water injection port 47 is opened on the left side of the cooling box 41 And the water outlet 48, the cooling pipe 49 is installed on the bottom side of the cooling box 41, and an observation window 46 is opened on the left side of the cooling box 41; the cooling water can be injected through the water injection port 47, and the height of the cooling water can be observed through the observation window 46. It is determined that the water level is higher than the cooling pipe 49 at the inner bottom end of the cooling box 41. The cooling water pipe has a three-layer structure to ensure sufficient cooling effect. The water outlet 48 on the left side of the cooling box 41 can remove excess water.

The front and rear sides of the cooling box 41 are provided with ventilation windows 42 to exchange heat with the outside. The rear side of the cooling box 41 is provided with a first air inlet 43 and a second air outlet 44, and a cooling pipe 49 The two ends are connected, and the second air outlet 44 is connected to the recovery and separation mechanism 6 through the second pipe 5.

The cooling mechanism 4 cools the water in the box by air cooling, and then further cools the gas in the pipe through sufficient contact between the cooling water and the cooling pipe 49, and the cooling rate of the gas can be adjusted by adjusting the rotation speed of the cooling fan 45.

The recovery and separation mechanism 6 includes a cylindrical recovery and separation box. The top side of the recovery and separation box is provided with a second air inlet 601 to introduce the cooled gas into the recovery and separation mechanism 6; There is a mesh screen mechanism, which can filter out powders of different particle sizes step by step. The mesh screen sealing cover 603 is provided on the outside of the mesh screen mechanism to achieve the effect of sealing the overall mechanism; the rear side of the recovery and separation mechanism 6 is provided with a gear sleeve 608 and a motor 607 , The motor 607 is connected to and drives the gear bushing 608, the gear bushing 608 is connected with a straight connecting rod 609, the straight connecting rod 609 is connected with a plurality of pinion gears 610, the chain rod through which the motor 607 drives a plurality of pinion gears 610 to be directly connected The rod 609 rotates on a shaft, and the pinion 610 drives the screen mechanism to perform centrifugal movement, which effectively separates the residues in the screen 615 around the periphery to achieve a collection effect, and at the same time avoids the drawbacks of the screen 615 that is easy to block under long-term use .

The mesh screen mechanism includes a plurality of single mesh screens 611, and the plurality of single mesh screens 611 are arranged in a vertical direction and fixed in the recovery separation box;

The single mesh screen 611 includes a first ring 619, a second ring 613, and a screen 615. The screen 615 is circular. The screen 615 is mounted on the first ring 619, the first ring 619 and the second ring 615. Piece 613 is positioned and locked.

The first ring member 619 includes a first frame body in a circular ring shape. The first frame body is provided with an annular collection groove 617. The top and bottom sides of the first frame body are both provided with an annular slide groove 616, and the annular slide groove 616 The cross-sectional shape is a trapezoid; a ring of gear teeth 618 is provided on the periphery of the first frame, and the gear teeth 618 can engage with the pinion 610 to drive the first ring 619 to perform centrifugal movement; the first frame also has a screen for installing的槽状结构。 Slot-like structure.

The second ring member 613 includes a second frame body in a ring shape. One side of the second frame body is provided with a spherical joint. , The second frame body cooperates with the annular sliding groove 616 through the spherical joint 612 to achieve the positioning effect; the other side of the second frame body is provided with a plurality of springs 614, and the spring 614 is connected to the box body of the recovery and separation mechanism 6 through the spring 614 Provide a certain pre-tightening force to fix the mesh screen mechanism.

Through this mesh screen mechanism, it is very convenient to exchange for mesh screen in later maintenance. At the same time, for the powder gas mixed with different particle sizes, the powder with different particle sizes in the screen 615 can be recovered by filtration, which is beneficial to the further recovery of the powder. deal with.

The lower end of the recovery and separation mechanism 6 is connected to a fixed platform 604, which serves to fix the recovery and separation box on the ground or other supporting foundations. The bottom side of the fixed platform 604 is connected to a number of fixed pillars 605 to support; There is a third air outlet 606. It can be understood that the fixed platform 604 and the recovery and separation box are connected to form a relatively closed box. The two fans 10 are connected, and a magnetic control switch 8 is provided at the interface of the waste water tank 7 to control the opening and closing of the pipeline. The wind intensity of the second fan 10 is greater than that of the first fan 11, which plays a role of blowback. When it is found that the powder recovery and separation is abnormal, it is mainly because the powder is stuck in the gap in the screen 615 and cannot be collected in the collection tank 617 by centrifugation. The pipe of the waste water tank 7 can be closed by the magnetic switch 8 and the first The second fan 10, because the wind strength is greater than the strength of the first fan 11, the gas flows from bottom to top, thereby blowing up the powder stuck in the screen 615, and the powder is collected in the collection tank 617 in time by the centrifugal effect of the screen mechanism.

The waste water tank 7 is mainly filled with water, which is used to absorb the ultrafine heavy metal particles and dust brought from the air, so as to avoid escaping into the air and causing harm to the human body and environmental pollution.

Example 3

In a typical embodiment of the present invention, a powder recovery and separation method is disclosed, using a powder recovery and separation device suitable for high-temperature environments as described in Example 2, including the following steps:

1) Start the first fan 11;

2) The powder enters the gas collecting box 1 through the collection port, and then enters the cooling box 41 for cooling;

3) After the powder is cooled in the cooling box 41, it enters the recovery and separation mechanism 6 for dust filtration;

4) In the recovery and separation mechanism 6, when an abnormality in powder recovery and separation is found, the pipe of the waste water tank 7 can be closed through the magnetic control switch 8, and the second fan 10 can be turned on. Since the strength of the wind is greater than the strength of the first fan 11, there is a gas from Flow downward and upward, thereby blowing up the powder stuck in the screen 615, and collecting the powder in the collection tank 617 in time through the centrifugal action of the screen mechanism.

In step 4), the abnormality of powder recovery and separation is mainly caused by the powder being stuck in the gaps in the screen 615 and cannot be collected in the collection tank 617 by centrifugation.

The above descriptions are only preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

A powder recovery and separation mechanism used in a high temperature environment, which is characterized by comprising a box body and a mesh screen mechanism arranged inside the box body. The mesh screen mechanism is connected to a power source. Centrifuge the powder in the mesh screen mechanism.
The powder recovery and separation mechanism used in a high-temperature environment according to claim 1, wherein the mesh screen mechanism comprises a plurality of monomer mesh screens arranged in parallel, and each of the monomer mesh screens is connected to a power source.
The powder recovery and separation mechanism used in a high-temperature environment according to claim 2, wherein each of the monomer mesh screens has a circular shape, and the periphery of each of the monomer mesh screens is provided for meshing The gear teeth of the power source.
The powder recovery and separation mechanism for high temperature environments according to claim 2, wherein each single mesh screen includes a first ring member, a second ring member and a screen, the first ring member and the second ring The ring member is buckled, and the screen is installed on the first ring member.
The powder recovery and separation mechanism used in a high-temperature environment according to claim 4, wherein the first ring member comprises a first frame body in a circular ring shape, and an annular collection groove is opened in the first frame body. Both the top and bottom sides of a frame are provided with annular slide grooves; the outer periphery of the first frame is provided with gear teeth, which can engage with the power source to drive the first ring member to perform centrifugal movement; It also has a trough-like structure for installing the screen.
The powder recovery and separation mechanism for high-temperature environments according to claim 4, wherein the second ring member includes a second frame body in a ring shape, and one side of the second frame body is provided with a spherical shape The joint can be connected to the top side and/or the bottom side of the first frame body; the other side of the second frame body is provided with a plurality of springs, and the springs are connected to the box body.
A powder recovery and separation system used in a high temperature environment, comprising a gas collection box, a negative pressure source, a cooling mechanism, the recovery and separation mechanism according to any one of claims 1 to 6, and a waste water tank, and the top side of the gas collection box Connected to the funnel-shaped air collecting port, the air collecting box is also connected to the negative pressure source and the cooling mechanism, the cooling mechanism is connected to the recovery and separation mechanism, and the recovery and separation mechanism is connected to the negative pressure source and the waste water tank.
The powder recovery and separation system used in a high-temperature environment according to claim 7, wherein the negative pressure source includes a first negative pressure source and a second negative pressure source, and the first negative pressure source is connected to the gas collecting box, The second negative pressure source is connected to the recovery and separation mechanism; the first negative pressure source and the second negative pressure source can be independently switched on and off.
The powder recovery and separation system used in a high-temperature environment according to claim 7, wherein the cooling mechanism includes a cooling box and a cooling fan connected above the cooling box; a water injection port is opened on the left side of the cooling box A cooling pipe is installed on the bottom side of the cooling box and the water outlet, and an observation window is also opened on the left side of the cooling box; the front and rear sides of the cooling box are equipped with ventilation windows, and the cooling box is also connected to a recovery and separation mechanism.
A powder recovery and separation method using the powder recovery and separation system for high temperature environments according to any one of claims 8-9, comprising the following steps:

Start the first negative pressure source;

The powder enters the air collecting box through the collection port, and then enters the cooling box for cooling;

After the powder is cooled in the cooling box, it enters the recovery and separation mechanism for dust filtration;

In the recovery and separation mechanism, when an abnormality in powder recovery and separation is found, the second negative pressure source is turned on, and the negative pressure value of the second negative pressure source is set to be smaller than the first negative pressure source, so that the gas in the box of the powder recovery and separation mechanism Flow from bottom to top, thereby blowing up the powder stuck in the screen, and collecting the powder in the collection tank in time through the centrifugal action of the screen mechanism.