Ultrafine powder conveying device for spraying

Abstract

The invention relates to a powder conveying device for conveying superfine powder for spraying, namely conveying powder which is small in density and particle size and easy to agglomerate in a thermal spraying process. Belongs to the technical field of thermal spraying. An ultrafine powder conveying device for spraying comprises a powder tank body, a gas carrying assembly and a powder feeding assembly. The powder feeding assembly comprises a conical surface mesopore baffle arranged in the powder tank body and provided with a downward opening, a straight pipe connector, a powder feeding hose and a powder feeding connector arranged on the wall of the powder tank body. According to the powder feeding device, after passing through the gas pressure valve and the gas flow meter, carrier gas enters the powder tank body through the gas feeding ring pipe exhaust hole in the carrier gas assembly at constant pressure and constant flow; quantitative control over the powder conveying amount can be achieved by adjusting the set values of the gas pressure valve and the gas flow meter; meanwhile, the gas carrying assembly is matched with the powder feeding assembly, powder is fed from bottom to top, and the adsorbed and agglomerated powder can be atomized.

Description

Technical Field

[0001] The invention relates to a powder feeding device, in particular to an ultrafine powder feeding device for spraying, that is, a powder feeding device for feeding powder with small density and particle size and easy to form agglomeration during thermal spraying, belonging to the technical field of thermal spraying. Background Art

[0002] In the thermal spraying process, the particle size and particle uniformity of the powder used for coating have a great influence on the quality of the coating. When the powder particle size is large, the powder has good fluidity and is easy to transport, but the powder is not easy to melt during the heating process of thermal spraying, resulting in the formation of voids in the coating and reducing the performance of the coating; when the powder particle size is small, the powder melting effect will be significantly improved. However, the smaller the particle size of the powder, the larger the specific surface area. When the powder is static and continuously transported, it is very easy to form adsorption agglomeration due to the combined action of multiple factors such as powder gravity, sliding friction between powder particles, electrostatic adsorption between powder particles, and van der Waals force, which greatly reduces the powder fluidity and significantly increases the difficulty of powder transportation. In severe cases, it may even block the powder delivery pipeline, making it impossible to transport the powder. This phenomenon is particularly serious for ceramic powders with low density, such as titanium oxide powder or aluminum oxide powder.

[0003] At present, the powder feeders commonly used in engineering are mainly rotary powder feeders, scraper powder feeders and vibrating powder feeders. When using a rotary powder feeder to transport fine powder, the powder feeding holes on the rotary disk are easily blocked by powder and powder cannot be output; when using a scraper powder feeder to transport fine powder, the powder outlet of the powder feeder is easily blocked by powder and powder cannot be output; when using a vibrating powder feeder to transport fine powder, the vibration device can continuously output powder, but the powder delivery amount is unstable and fluctuates with the frequency of the vibrator, which will have a great impact on the spraying effect.

[0004] The Chinese invention patent with the authorization announcement number CN 100446870C discloses a cold air power spraying method and device with downstream powder delivery. The method is to heat the working gas and input it into the convergent section upstream of the Raoult-type nozzle flow channel, and the gas expands and accelerates in the downstream divergent section after passing through the nozzle throat; the metal powder particles to be sprayed in the powder feeder are directly sent into the downstream divergent section of the nozzle by the carrier gas, and then accelerated to supersonic speed by the working gas therein; the powder particles to be sprayed are directly delivered to the downstream divergent section of the nozzle from the outside of the nozzle through the powder delivery holes on the side wall of the nozzle via the powder delivery pipe; the cross section of the divergent section flow channel is an elliptical-rectangular combination, the axes of all the powder delivery holes on the side wall of the nozzle are in the same plane with the major axis of the ellipse, the ellipse major axis plane is the longitudinal section where the major axis of the ellipse of the flow channel cross section is located, the outlets of all the powder delivery holes are located in the divergent section downstream of the nozzle, and the powder particles are accelerated by the working gas and sprayed from the outlet end of the divergent section of the nozzle. This solution can effectively solve the problem of powder clogging the nozzle, but because the powder delivery pipe is connected to the divergent section downstream of the nozzle, the stability of the powder flow depends not only on the flow and velocity of the carrier gas, but also has a direct relationship with the heating pipeline. When the hot air flow in the heating pipeline is unstable, the powder cannot be output stably and continuously. In addition, there are certain problems with the mixing uniformity of the powder and the carrier gas in the powder delivery pipeline. Summary of the invention

[0005] The present invention aims to solve the above problems and thus provides a powder feeding device, which is suitable for the field of thermal spraying technology, especially for feeding powder in the thermal spraying process, and aims to solve the problem of agglomeration caused by small powder particle size, which affects powder transportation.

[0006] A superfine powder conveying device for spraying, comprising a powder tank body, a carrier gas assembly having one end for inputting exogenous compressed gas and the other end communicating with the inner cavity of the powder tank body, and a powder delivery assembly having one end communicating with the inner cavity of the powder tank body and the other end for connecting to a thermal spray gun; the powder delivery assembly comprises a conical middle hole baffle plate which is arranged in the powder tank body and divides the inner space of the powder tank body into two upper and lower cavities, the conical middle hole baffle plate opening faces downward and has a constriction arranged upward; the powder delivery assembly also comprises a straight pipe joint integrally connected to the constriction, a powder delivery hose having a first end sleeved with the straight pipe joint, and a powder delivery joint arranged on the wall of the powder tank body and connected to the second end of the powder delivery hose.

[0007] The present invention inputs gas of fixed pressure and fixed flow rate into the powder tank from bottom to top from the gas carrier assembly, so that the powder in the tank gradually converges along the conical middle hole baffle under the action of the airflow, enters the hose through the necking and straight pipe joint, and then reaches the powder feeding joint connected with the hose for feeding the thermal spray gun, finally achieving the purpose of outputting from the upper end of the powder tank and feeding the thermal spray gun.

[0008] In the above technical solution of the present invention, the conical surface middle hole baffle refers to a baffle with a conical surface structure in the shape of a bell mouth, and because the middle part of the baffle has a hole-shaped constriction structure, it is called a conical surface middle hole baffle. The conical surface middle hole baffle divides the internal space of the powder tank into two upper and lower cavities because any edge of the conical surface middle hole baffle abuts against the inner wall of the powder tank.

[0009] As a preferred embodiment of the above technical solution, the carrier gas assembly includes a carrier gas ring tube disposed inside the powder tank, the carrier gas ring tube is evenly spaced with a plurality of exhaust holes, and the exhaust holes are disposed toward the bottom of the powder tank. The exhaust holes have an air hole diameter of 1 to 1.5 mm.

[0010] In the bottom-up conveying process, the gas pressure will first atomize the powder in the powder tank, increase the spacing between all powder particles, significantly reduce the effects of various factors that cause the powder to adsorb and agglomerate together, thereby eliminating the adsorption agglomeration formed by the powder in a static state, and effectively improve the fluidity of the powder. As the atomized powder passes through the conical middle hole baffle to reach the lower end of the powder delivery assembly, the gas pressure will gradually increase at the same gas flow rate due to the gradual decrease in the channel diameter. When it reaches the conical middle hole baffle, the gas pressure reaches the maximum, and the atomized powder can be quickly delivered to the hose of the powder delivery assembly. Therefore, during the conveying process, the powder delivery assembly will not be blocked. The exhaust hole with a diameter of 1~1.5mm on the carrier gas ring tube can ensure that the gas pressure output by the carrier gas ring tube is higher, so as to better blow up the powder.

[0011] There is a distance from the lower end of the powder tank to the powder delivery assembly. When there is a powder cluster that forms a large adsorption agglomeration and cannot be atomized, it will not enter the powder delivery assembly with the airflow due to its relatively large mass. In the above technical solution of the present invention, the exhaust hole is set downward. When the gas hits the bottom, it will rush back in the opposite direction, which can drive the powder to rise. Then, with the transportation of the airflow, the powder can be evenly delivered. The implementation of this technical solution can improve the conveying performance of powders with higher sedimentation. At the same time, since the final flow direction of the airflow is opposite to the direction when the airflow is just discharged from the exhaust hole, a vortex can be generated in the local space, which can not only avoid or slow down the deposition of the powder, but also avoid or slow down the agglomeration of the powder.

[0012] As a preferred embodiment of the above technical solution, the gas carrier assembly also includes a gas supply straight pipe, and a three-way joint, a gas supply joint, a gas flow meter and a gas pressure valve connected in sequence through the gas supply straight pipe; two of the openings of the three-way joint are respectively connected to the two interfaces of the carrier gas ring pipe.

[0013] By adjusting the gas pressure and gas flow, it is possible to achieve a stable and continuous output of quantitative powder for thermal spraying. At the same time, for some thermal spraying methods, using finer powder for thermal spraying can effectively improve the quality and performance of the coating prepared by thermal spraying.

[0014] As a preferred embodiment of the above technical solution, a plurality of grooves for generating cyclones are arranged on the inner conical surface of the conical hole baffle.

[0015] In the above technical solution of the present invention, the setting of the groove facilitates the generation of cyclones inside the cavity, so that the powder can be swirled in a local area, further improving the suspension properties of the powder and avoiding agglomeration; at the same time, it can also enable the powder to produce a certain degree of spiral feeding when being transported in the pipeline, thereby further improving the distribution uniformity and conveying flow rate of the powder dispersed in the carrier gas medium.

[0016] As a preferred embodiment of the above technical solution, the groove is a spiral groove.

[0017] As a preferred embodiment of the above technical solution, the powder tank body includes a tank body straight section, a tank body upper cover and a tank body lower conical section, the upper end of the tank body straight section is provided with a tank body flange, and the tank body upper cover is gland-connected to the tank body flange; the bottom of the tank body lower conical section is provided with a powder discharge hole, and a powder discharge plug is provided on the powder discharge hole.

[0018] As a preferred embodiment of the above technical solution, a step opening is provided on the end surface of the lower conical section of the tank body to facilitate the installation of the straight section of the tank body.

[0019] As a preferred embodiment of the above technical solution, a threaded hole corresponding to the screw hole of the tank flange is arranged on the end surface of the lower cone section of the tank body, and the tank flange, the tank straight section and the lower cone section of the tank body are connected by a long screw.

[0020] As a preferred embodiment of the above technical solution, a tank flange sealing ring is provided between the tank straight section and the tank flange, and a tank lower cone section sealing ring is provided between the tank straight section and the tank lower cone section.

[0021] As a preferred embodiment of the above technical solution, the gas carrier assembly is communicated with the inner cavity of the powder tank body through an air supply hole provided on the wall of the lower cone section of the tank body or the powder discharge hole.

[0022] In the above technical scheme of the present invention, when the air supply hole is arranged in the lower cone section of the tank body, the carrier gas sprayed from the exhaust hole first passes through the convergence effect of the inner wall of the lower cone section. Due to the reduction of space, the carrier gas flow rate increases rapidly, thereby improving the blowing effect on the inner wall of the lower cone section of the tank body; at the same time, due to the convergence of the air flow, the recoil gas flow rate is also enhanced, thereby further improving the dust-raising effect of the recoil air flow, making the powder in the tank body more easily in a suspended state, and also increasing the probability of collision between powder particles, avoiding or slowing down the agglomeration effect of the powder.

[0023] In the above technical solution of the present invention, when the air supply hole is arranged on the wall of the powder discharge hole, the recoil gas is first released in a confined space, and then due to the continuous release, the airflow quickly diffuses upward along the inner wall of the lower cone section of the tank body. The inner wall of the lower cone section of the tank body guides the diffusion of the airflow and promotes the dispersion of the powder. Therefore, it can effectively solve the problem of easy accumulation of powder at the original powder discharge hole.

[0024] In summary, the present invention has the following beneficial effects: 1. In the ultrafine powder delivery device for spraying described in the present invention, after the carrier gas passes through the gas pressure valve and the gas flow meter, it passes through the exhaust hole of the gas delivery ring pipe in the carrier gas assembly at a constant pressure and a constant flow rate and enters the powder tank; by adjusting the set values ​​of the gas pressure valve and the gas flow meter, quantitative control of the powder delivery amount can be achieved; 2. In the ultrafine powder conveying device for spraying described in the present invention, the exhaust holes of the air supply ring tube are evenly distributed in the circumferential direction of the air supply ring tube, and the diameter of the exhaust holes of the air supply ring tube is about 1mm~1.5mm; the exhaust holes are evenly distributed, which can ensure that the gas introduced from the exhaust holes is evenly discharged along the circumferential direction of the powder delivery tank body, so that the amount of powder blown up on the cross section of the powder delivery tank body is consistent and stable; it is avoided that due to the large gas flow introduced in one direction, the powder is blown up too much in one direction, and the powder is locally agglomerated near the center hole of the conical hole baffle due to the large amount of powder, causing the powder delivery component to be blocked; 3. In the ultrafine powder conveying device for spraying described in the present invention, the air supply ring is located at the bottom of the lower cone section of the tank body, and the exhaust hole of the air supply ring is opened downward. The exhaust hole of the air supply ring is opened downward to ensure that the introduced gas first passes downward into the powder delivery tank body to blow up the gas powder located below the air supply ring. The gas passes through the recoil at the bottom of the lower cone section of the tank body and is then transported from bottom to top, thereby preventing the part of the powder located at the bottom of the powder delivery tank body at the lower end of the air supply ring from being unable to be blown up. If the exhaust hole of the air supply ring is directed upward, the pressure of the gas is relatively high when it is discharged from the exhaust hole, which may cause turbulence in the powder delivery tank body and affect the stability of powder delivery. It may also form downward gas pressure on the powder below the air supply ring, compacting the powder at this position and aggravating the powder agglomeration. Once the powder with aggravated agglomeration at the bottom is blown up, it will affect the stability of powder delivery. 4. In the ultrafine powder conveying device for spraying described in the present invention, the conical middle hole baffle is inverted in the powder tank. The powder filled in the powder tank is blown into the center hole of the conical middle hole baffle by the gas entering the powder tank from below, passes through the powder delivery assembly, and is finally transported out from the upper end of the powder tank. Under the condition of constant gas flow, when the cross-sectional area of ​​the channel for conveying gas is smaller, the gas pressure is greater, and the conical middle hole baffle is inverted in the powder tank, which can ensure that the gas pressure gradually increases during the smooth airflow conveying process of the powder until the gas blows the powder into the powder delivery assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of an ultrafine powder conveying device for spraying according to Embodiment 1 of the present invention; Figure 2 yes Figure 1 A schematic diagram of the structure of a powder tank of an ultrafine powder delivery device for spraying; Figure 3 yes Figure 1 A schematic diagram of the structure of a carrier gas assembly of an ultrafine powder delivery device for spraying; Figure 4 yes Figure 1 A schematic diagram of the structure of a powder delivery assembly of an ultrafine powder delivery device for spraying; Figure 5 yes Figure 4 A schematic diagram of the structure of the groove of the powder feeding assembly; Reference numerals: 100. Powder tank, 200, carrier gas assembly, 300, powder feeding component, 400, tank base, 101. Tank cover, 102. Tank flange, 103. Tank straight section, 104. Lower cone section of the tank body, 105. Long screw, 106. Tank flange sealing ring, 107. Sealing ring of the lower cone section of the tank body, 108. Powder discharge plug, 109. Powder feeding hole, 110. Air supply hole, 111. Powder discharge hole, 112. Screw hole, 113. Threaded hole, 201, carrier gas loop tube, 202, air supply straight pipe, 203, tee connector, 204, air supply connector, 205. Gas flow meter, 206. Gas pressure valve, 207, exhaust hole, 301, cone-shaped center hole baffle, 302, straight pipe joint, 303, powder delivery hose, 304, powder feeding connector, 301-1, shrinking, 301-2, groove. DETAILED DESCRIPTION

[0026] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the present invention will be more comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0027] Furthermore, the drawings are merely schematic illustrations of the present invention and are not drawn to scale; some blocks shown in the drawings are functional entities and do not necessarily correspond to physically or logically separate entities.

[0028] Example 1 like Figure 1 As shown, this exemplary embodiment provides an ultrafine powder delivery device for spraying, which mainly includes: a powder tank 100, a carrier gas assembly 200, a powder delivery assembly 300 and a tank base 400.

[0029] Specifically, Figure 2 As shown, the powder tank 100 includes: a tank cover 101, a tank flange 102, a tank straight section 103, and a tank lower conical section 104. A long screw 105 passes through a screw hole 112 on the tank flange 102 and is screwed into a threaded hole 113 on the tank lower conical section 104. After the long screw 105 is tightened, the tank flange 102 and the tank lower conical section 104 can clamp the tank straight section 103. In order to ensure the sealing of the powder tank, a tank flange sealing ring 106 is installed between the tank flange 102 and the tank straight section 103, and a tank lower conical section sealing ring 107 is installed between the tank straight section 103 and the tank lower conical section 104. The lower end straight hole of the tank lower conical section 104 is a powder discharge hole 111, which is sealed with a powder discharge plug 108. After the spraying operation is completed, the powder discharge plug 108 is opened to discharge the remaining powder in the recovery tank. On the side wall of the lower cone section 104 of the tank body near the bottom, there is an air delivery hole 110 for delivering air or a carrier gas such as nitrogen or argon into the tank body. On the side wall of the tank body flange 102, there is a powder delivery hole 109 for the final discharge of the powder.

[0030] like Figure 3 As shown, the carrier gas assembly 200 includes a gas pressure valve 206 and a gas flow meter 205, which are used to adjust the pressure and flow of the powder delivery gas. The outer end of the gas delivery connector 204 installed on the gas delivery hole 110 is connected to the gas delivery pipe, and the inner end is connected to the gas delivery straight pipe 02 inside the powder tank 100. The gas delivery straight pipe 202 is connected to the carrier gas ring pipe 201 through a three-way connector 203. On the lower side of the carrier gas ring pipe 201, there are multiple gas delivery ring pipe exhaust holes with a diameter of 1mm~1.5mm distributed along the circumference of the ring pipe.

[0031] like Figure 4 As shown, the powder delivery assembly 300 is located in the powder tank 100, and a conical hole baffle 301 is formed at the center of the upper end to form a conical conical hole 301 and a circular hole, which is then connected to the straight pipe joint 302 by welding. One end of the powder delivery hose 303 is connected to the straight pipe joint 302, and the other end is connected to the powder delivery joint 304 installed on the powder delivery hole 109.

[0032] like Figure 5 As shown, a plurality of grooves 301-2 for generating cyclones are arranged on the inner conical surface of the conical middle hole baffle 301. Furthermore, the grooves 301-2 present a double helix structure composed of two groups of spirals as a whole, and each group of spirals is composed of eight independent arc-shaped grooves; the grooves 301-2 are evenly distributed on the inner conical surface of the conical middle hole baffle 301, and each groove 301-2 affects about 1 / 8 of the area of ​​a spiral circle, and the evenly distributed eight arc-shaped grooves just constitute a complete spiral circle, that is, a spiral depth of about one pitch. Furthermore, from an axial perspective, the distribution of the two groups of spirals on the inner conical surface of the conical middle hole baffle 301 differs by half a pitch. Furthermore, from a radial perspective, the two groups of spirals have a common spiral center, and the distribution position of the second group of spirals on the inner conical surface of the conical hole baffle 301 is closer to the spiral center, and the position difference between the two is 1 / 10 of the spiral radius; the spiral radius, that is, the distance from the starting point of the spiral to the spiral center, is the length of the farthest end of the groove 301-2 constituting the first group of spirals from the spiral center.

[0033] Working process: 1) With the powder discharge plug 108 tightened, unscrew the tank cover 101, take out the conical middle hole baffle 301 through the powder delivery hose 303, and pour in the powder. Put the conical middle hole baffle 301 back into the powder tank, adjust it to the approximate center position, and tighten the tank cover 101.

[0034] 2) Turn on the carrier gas switch, and adjust the gas pressure valve 206 and the gas flow meter 205 to the set value, so that the carrier gas enters the powder delivery tank at a constant pressure and constant flow rate. The carrier gas enters the carrier gas ring tube 201 through the three-way joint 203 and the gas delivery straight pipe 202, and enters the bottom of the powder tank 100 from the exhaust hole 207 of the carrier gas ring tube; Since the exhaust holes 207 are evenly distributed along the circumferential direction, the carrier gas also enters the powder tank 100 evenly from below along the circumferential direction and can blow up the powder evenly, so that the agglomeration of the powder in the powder tank 100 is effectively alleviated or completely dispersed. The blown powder will gradually rise along the conical middle hole baffle 301, gather at the center hole position, and be transported out through the powder delivery hose 303 and the powder delivery connector 304; Furthermore, the powder delivery amount can be changed by adjusting the carrier gas pressure and flow rate. When conveying the same type of powder, if the powder delivery amount is not adjusted much, it is recommended to adjust the carrier gas flow rate first and keep the carrier gas pressure unchanged; when the powder delivery amount changes greatly or the conveyed powder is changed, such as changing the carrier gas flow rate cannot achieve the specified powder delivery amount, it is necessary to adjust the carrier gas pressure and then adjust the carrier gas flow rate so that the final output powder delivery amount meets the conveying requirements.

[0035] For example, when using the above-mentioned ultrafine powder conveying device for spraying to convey Al2O3 powder (powder particle size is 5μm~15μm), the carrier gas pressure is 0.7MPa, the carrier gas flow rate is 15L / min, and the powder delivery amount is 437g / h; the carrier gas pressure is 0.7MPa, the carrier gas flow rate is 20L / min, the powder delivery amount is 652g / h; the carrier gas pressure is 0.6MPa, the carrier gas flow rate is 15L / min, and the powder delivery amount is 382g / h. When using the above-mentioned powder delivery device to convey TiO2 powder (powder particle size is 5μm~15μm), the carrier gas pressure is 0.7MPa, and the carrier gas flow rate is 20L / min, and the powder delivery amount is 725g / h.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A superfine powder conveying device for spraying, comprising a powder tank (100), a gas carrier component (200) having one end for inputting exogenous compressed gas and the other end communicating with the inner cavity of the powder tank (100), and a powder conveying component (300) having one end communicating with the inner cavity of the powder tank (100) and the other end connected to a thermal spray gun; characterized in that: The powder delivery assembly (300) comprises a conical middle hole baffle (301) arranged in the powder tank (100) and dividing the internal space of the powder tank (100) into two upper and lower cavities, the conical middle hole baffle (301) opening downward and having a constriction (301-1) arranged upward; the powder delivery assembly (300) further comprises a straight pipe joint (302) integrally connected to the constriction (301-1), a powder delivery hose (303) with a first end sleeved with the straight pipe joint (302), and a powder delivery joint (304) arranged on the wall of the powder tank (100) and connected to the second end of the powder delivery hose (303).

2. The ultrafine powder conveying device for spraying according to claim 1, characterized in that: The carrier gas assembly (200) comprises a carrier gas ring tube (201) arranged inside the powder tank body, a plurality of exhaust holes (207) are evenly spaced on the carrier gas ring tube (201), and the exhaust holes (207) are arranged toward the bottom of the powder tank body (100).

3. The ultrafine powder conveying device for spraying according to claim 2, characterized in that: The carrier gas assembly (200) further comprises a straight gas supply pipe (202), and a three-way joint (203), a gas supply joint (204), a gas flow meter (205), and a gas pressure valve (206) which are sequentially connected via the straight gas supply pipe (202); two openings of the three-way joint (203) are respectively connected to two interfaces of the carrier gas ring pipe (201).

4. The ultrafine powder conveying device for spraying according to claim 1, characterized in that: A plurality of grooves (301-2) for generating cyclones are arranged on the inner conical surface of the conical middle hole baffle (301).

5. The ultrafine powder conveying device for spraying according to claim 4, characterized in that: The groove (301-2) is a spiral groove.

6. The ultrafine powder conveying device for spraying according to claim 2, characterized in that: The powder tank body (100) comprises a tank body straight section (103), a tank body upper cover (101) and a tank body lower conical section (104); a tank body flange (102) is provided at the upper end of the tank body straight section (103); the tank body upper cover (101) is press-connected to the tank body flange (102); a powder discharge hole (111) is provided at the bottom of the tank body lower conical section (104); and a powder discharge plug (108) is provided on the powder discharge hole (111).

7. The ultrafine powder conveying device for spraying according to claim 6, characterized in that: The end surface of the lower conical section (104) of the tank body is provided with a step opening for facilitating the installation of the straight section (103) of the tank body.

8. The ultrafine powder conveying device for spraying according to claim 6, characterized in that: A threaded hole (113) corresponding to the screw hole (112) of the tank flange (102) is provided on the end surface of the tank lower cone section (104); the tank flange (102), the tank straight section (103) and the tank lower cone section (104) are connected via a long screw (105).

9. The ultrafine powder conveying device for spraying according to claim 8, characterized in that: A tank flange sealing ring (106) is provided between the tank straight section (103) and the tank flange (102), and a tank lower cone section sealing ring (107) is provided between the tank straight section (103) and the tank lower cone section (104).

10. The ultrafine powder conveying device for spraying according to claim 6, characterized in that: The gas carrier assembly (200) is communicated with the inner cavity of the powder tank body (100) through a gas delivery hole (110) provided on the wall of the tank body lower cone section (104) or the powder discharge hole (111).

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