Coating chamber and powder coating device

Abstract

The present invention relates to a powder coating device and a coating cavity. Fluidizing gas is filled from the air inlet port, so that the powder can obtain a higher initial velocity and fluidize. Since the area of ​​the flow cross section of the inner cavity tends to increase in the direction from the air inlet port to the air outlet port. According to the fluid equation, the gas flow rate in the direction from the air inlet port to the air outlet port will show a decreasing trend. When the flow rate drops to a certain level, the lifted powder will gradually begin to settle and be lifted again when it approaches the air inlet port. Therefore, the powder will form an internal circulation within a limited height, thereby increasing the interaction between powder particles and reducing agglomeration. At the same time, since the height of the powder lifting is limited, the powder can be prevented from touching and adsorbing on the air outlet port. Moreover, the powder forming the internal circulation increases the impact on the cavity wall and reduces the powder adsorbed on the cavity wall. Therefore, the uniformity of the coating is significantly improved.

Description

Technical Field

[0001] The present invention relates to the field of film coating technology, and in particular to a film coating chamber and a powder film coating device. Background Art

[0002] The surface functionalization of powder particles is an important part of material surface engineering technology, especially for improving the original performance of particles. The surface functionalization of powder particles can be achieved by coating the surface of powder particles, i.e. coating.

[0003] Atomic layer deposition technology has been widely used in the process of coating powder particles due to its better uniformity, conformality and size controllability. In the current coating process, the equipment generally used is fluidized bed ALD (Atomic layer deposition) equipment. Fluidized bed ALD equipment needs to continuously evacuate the reaction chamber and fill it with fluidizing gas. In this way, the powder particles in the reaction chamber will be fluidized and dispersed.

[0004] However, dispersed powder particles often adsorb on the inner wall or port of the reaction chamber, resulting in the inability to effectively coat some of the contact areas between particles. In particular, when coating a large number of powder particles, the deposition uniformity is poor, resulting in poor uniformity of the final coating. Summary of the invention

[0005] Based on this, it is necessary to provide a coating chamber and a powder coating device that can improve the uniformity of coating in order to solve the above problems.

[0006] A coating cavity comprises an inner cavity, wherein an air inlet port and an air outlet port are respectively formed at two axial ends of the inner cavity, and the powder to be coated can be accommodated in one end of the inner cavity close to the air inlet port, and in the direction from the air inlet port to the air outlet port, the area of ​​the flow cross-section of the inner cavity tends to increase.

[0007] In one embodiment, the inner cavity includes a first straight pipe section, a second straight pipe section and a tapered pipe section, the inner diameter of the first straight pipe section is smaller than the inner diameter of the second straight pipe section, and the first straight pipe section and the second straight pipe section are respectively connected to the small end and the large end of the tapered pipe section, the air inlet port and the air outlet port are respectively arranged in the first straight pipe section and the second straight pipe section, and the powder to be coated can be accommodated in the first straight pipe section.

[0008] In one embodiment, the cone angle of the cone tube section is 10 degrees to 140 degrees.

[0009] In one of the embodiments, it further includes an outer cavity, the inner cavity is accommodated in the outer cavity, and the air outlet port is communicated with the outer cavity, and an exhaust port is formed at one end of the outer cavity away from the air outlet port.

[0010] In one of the embodiments, it also includes a vibration mechanism that can drive the inner cavity to vibrate.

[0011] In one embodiment, it further includes a vibration mechanism capable of driving the inner cavity to vibrate relative to the outer cavity, and the vibration mechanism includes:

[0012] Vibration source;

[0013] A connecting rod is inserted into the outer cavity and has two ends fixedly connected to the outer wall of the inner cavity and the vibration source respectively; and

[0014] The bellows is sleeved on the connecting rod, and the two ends of the bellows are respectively sealed and connected to the outer wall of the inner cavity and the inner wall of the outer cavity.

[0015] A powder coating device, comprising:

[0016] A coating chamber as described in any one of the above preferred embodiments;

[0017] An air circuit system, connected to the air inlet port and used to fill the inner cavity with gas;

[0018] A heating system, used to heat the coating chamber and the gas path system; and

[0019] The exhaust mechanism is connected to the coating cavity and exhausts air from the inner cavity through the air outlet port.

[0020] In one of the embodiments, it further includes an exhaust gas treatment mechanism disposed between the exhaust mechanism and the coating chamber.

[0021] In one of the embodiments, the suction rate of the suction mechanism for evacuating the inner cavity is adjustable.

[0022] In one embodiment, the vacuum mechanism includes a vacuum pump and a butterfly valve disposed between the vacuum pump and the coating chamber.

[0023] In one embodiment, the vacuum mechanism includes a vacuum pump and an exhaust bypass connected in parallel with the vacuum pump and capable of being opened or closed, wherein an exhaust rate of the exhaust bypass is lower than an exhaust rate of the vacuum pump.

[0024] The powder coating device and coating chamber mentioned above are filled with fluidizing gas from the air inlet port, so that the powder can obtain a higher initial velocity and fluidize. Since the area of ​​the flow cross-section of the inner cavity tends to increase in the direction from the air inlet port to the air outlet port. According to the fluid equation, the gas flow rate in the direction from the air inlet port to the air outlet port will show a decreasing trend. When the flow rate drops to a certain level, the lifted powder will gradually begin to settle and be lifted again when it approaches the air inlet port. Therefore, the powder will form an internal circulation within a limited height, thereby increasing the interaction between the powder particles and reducing agglomeration. At the same time, since the height of the powder lifting is limited, the powder can be prevented from touching and adsorbing on the air outlet port. Moreover, the powder forming the internal circulation increases the impact on the cavity wall and reduces the powder adsorbed on the cavity wall. Therefore, the uniformity of the coating is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the structure of a powder coating device in a preferred embodiment of the present invention;

[0027] Figure 2 for Figure 1 A schematic diagram of the structure of the inner cavity of the coating cavity in the powder coating device shown;

[0028] Figure 3 for Figure 2 Simulation of air flow velocity distribution in the inner cavity shown;

[0029] Figure 4 for Figure 2 The relationship between the air intake volume and the splash zone height under different pressures in the inner cavity is shown. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0033] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0036] See also Figure 1 The present invention provides a powder coating device 10 and a coating chamber 100 . The powder coating device 10 includes a coating chamber 100 , an air path system 200 , a heating system 300 and an exhaust mechanism 400 .

[0037] The coating chamber 100 has a reaction chamber formed therein for the powder to be coated, such as micro-nano particles, to react and obtain a coating layer coated on the surface of the powder particles. The coating chamber 100 can be a single-layer chamber or a double-layer chamber structure.

[0038] Please also read Figure 2 The coating chamber 100 in the preferred embodiment of the present invention includes an inner cavity 110. The interior of the inner cavity 110 can form the above-mentioned reaction chamber. Moreover, an air inlet port (not shown) and an air outlet port (not shown) are respectively formed at both ends of the axial direction of the inner cavity 110, and the powder to be coated can be accommodated in one end of the inner cavity 110 close to the air inlet port. The air inlet port and the air outlet port are generally provided with a filter screen, which can allow the precursor and the purge gas to pass through and can block the powder particles to be coated. In addition, the air inlet port and the air outlet port can also be provided with air connection flanges.

[0039] Furthermore, in the direction from the air inlet port to the air outlet port, the area of ​​the flow cross section of the inner cavity 110 tends to increase. The flow cross section refers to the flow cross section when the air flows from the air inlet port to the air outlet port. That is, the cross section is obtained by cutting the cross section in a direction perpendicular to the axial direction of the inner cavity 110. The area of ​​the flow cross section can have a trend of continuous increase or a trend of step-by-step increase.

[0040] The gas circuit system 200 is connected to the gas inlet port and is used to fill the inner cavity 110 with gas. The gas circuit system 200 generally includes a process gas circuit and a fluidizing gas circuit, which are respectively used to fill the inner cavity 110 with precursors, purge gas and fluidizing gas. The gas circuit system 200 can adopt relevant settings in the prior art. For example, the process gas circuit in the gas circuit system 200 includes a process gas pipeline, a source bottle connected to the process gas pipeline, a gas mass flow controller, etc. The fluidizing gas circuit includes a pulse valve, a gas mass flow controller, and a fluidizing gas pipeline. Among them, the source bottle is used to hold a precursor source in liquid or solid form, and the gas mass flow controller is used to introduce a specified flow of precursor into the reaction chamber. Opening the pneumatic valve (not marked) on the source bottle can realize that the nitrogen purge gas carries the precursor into the inner cavity 110, and closing the pneumatic valve on the source bottle can realize the function of only introducing nitrogen (i.e., purge gas). If multiple precursors need to be provided to the reaction chamber, multiple process gas pipelines can be set according to the actual needs of process production. In addition, pulse valves can be set on the process gas pipelines to control the multiple precursors to enter the reaction chamber alternately.

[0041] The heating system 300 is used to heat the coating chamber 100 and the gas system 200. The heating system 300 can be an electric heating component, which generally includes two parts. One part can be an electric heating plate structure coated on the outside of the coating chamber 100, which can conduct heat to the reaction chamber when powered on; the other part is a soft-pack heating belt that can be wrapped on the pipes of the gas system 200 and the source bottle. The main function of the heating system is to achieve and maintain a suitable temperature in the reaction chamber, usually 40℃ to 350℃.

[0042] In order to accurately control the temperature in the reaction chamber, a temperature measuring terminal 140 is further provided on the coating chamber 100 . The temperature measuring terminal 140 is used to monitor the temperature in the inner chamber 110 , and can be displayed on a display screen provided outside the coating chamber 100 .

[0043] The exhaust mechanism 400 is connected to the coating chamber 100 and exhausts the inner chamber 110 through the gas outlet port. The exhaust mechanism 400 is used to evacuate the reaction chamber to ensure that the reaction area is isolated from the air. The exhaust mechanism 400 can be a vacuum pump, an exhaust valve, or other structures.

[0044] Specifically in this embodiment, the powder coating device 10 further includes an exhaust gas treatment mechanism 500 disposed between the exhaust mechanism 400 and the coating chamber 100. When the exhaust mechanism 400 is exhausting, the exhaust gas in the reaction chamber will first be exhausted into the exhaust gas treatment mechanism 500, and then a certain amount of air will be filled in to react with it to generate harmless particles.

[0045] The process of the powder coating device 10 performing the coating process is roughly as follows:

[0046] The powder to be coated is loaded into the inner cavity 110; the exhaust mechanism 400 is started to evacuate the reaction cavity, thereby maintaining effective isolation between the reaction cavity and the air environment; the heating system 300 is turned on for heating, so that the reaction cavity reaches the appropriate temperature required for the reaction; the gas circuit system 200 is turned on, and the fluidizing gas is first introduced into the reaction cavity to fluidize and fully disperse the powder particles; then the first precursor is introduced into the reaction cavity and adsorbed on the surface of the powder particles; the purge gas is introduced to remove the excess first precursor in the reaction cavity; the second precursor is introduced into the reaction cavity to react with the first precursor adsorbed on the surface of the powder particles to form a coating layer; the purge gas is introduced to remove the excess second precursor in the reaction cavity.

[0047] If necessary, the above steps can be repeated until the thickness of the coating layer meets the requirements.

[0048] In the process of the gas path system 200 introducing fluidizing gas into the reaction chamber and fluidizing the powder particles, the powder particles first obtain a large initial velocity near the air inlet port and quickly splash toward the air outlet port. According to the principles of fluid mechanics, under the premise of a certain flow rate, the smaller the flow cross-section, the greater the flow rate. Therefore, the flow rate of the gas will show a decreasing trend in the direction from the air inlet port to the air outlet port. When the fluidized powder splashes toward the air outlet port and the flow rate drops to a certain level, the pressure difference will not be enough to support the powder. At this time, the lifted powder will gradually begin to settle and be lifted again when it is close to the air inlet port. In this reciprocating manner, the powder will form an internal circulation within a limited height in the inner cavity 110, thereby increasing the interaction between the powder particles and reducing agglomeration.

[0049] At the same time, since the height of the powder being lifted is limited, the powder can be prevented from touching and being adsorbed on the air outlet port, thereby preventing the air outlet port from being blocked or a large amount of powder from being adsorbed on the filter screen of the air outlet port. Moreover, the powder forming an internal circulation increases the impact on the wall of the inner cavity 110 and reduces the amount of powder adsorbed on the wall. Therefore, the uniformity of the coating is significantly improved.

[0050] In this embodiment, the exhaust rate of the exhaust mechanism 400 for exhausting the inner chamber 110 is adjustable. When the first precursor and the second precursor are charged into the reaction chamber, the exhaust rate of the exhaust mechanism 400 can be reduced so that the air intake rate in the reaction chamber is greater than the exhaust rate. In this way, a higher pressure can be maintained in the reaction chamber.

[0051] When the pressure in the reaction chamber increases, on the one hand, it can prevent the precursor from being drawn away before it has time to adsorb or react, increasing the time the precursor stays in the reaction chamber, thereby ensuring that sufficient adsorption reaction occurs on the surface of the powder and reducing waste. On the other hand, it can also reduce the pressure difference between the exhaust side (exhaust port) and the intake side (intake port), thereby effectively controlling the height of the splash zone during powder fluidization. In this way, it can prevent the adsorption and removal of the precursor from being affected by a large amount of powder adsorbed on the exhaust side, thereby improving the growth efficiency of the coating layer.

[0052] like Figure 4 As shown, the higher the pressure in the reaction chamber, the lower the height of the powder splashing zone is under the premise of the same air intake flow rate.

[0053] When the purge gas is introduced to remove the excess precursor, the exhaust rate of the exhaust mechanism 400 can be increased. In this way, the excess precursor can be removed quickly, which helps to improve the coating efficiency.

[0054] There are many ways to adjust the air extraction rate of the air extraction mechanism 400. For example:

[0055] Please refer again Figure 1 In this embodiment, the exhaust mechanism 400 includes a vacuum pump 410 and a butterfly valve 420 disposed between the vacuum pump 410 and the coating chamber 100. Since the power of the vacuum pump 410 remains unchanged after it is started, the exhaust rate of the entire exhaust mechanism 400 can be adjusted by controlling the opening degree of the butterfly valve 420.

[0056] Another example:

[0057] In another embodiment, the vacuum mechanism 400 includes a vacuum pump and an exhaust bypass (not shown) connected in parallel with the vacuum pump and capable of being opened or closed, wherein the exhaust rate of the exhaust bypass is lower than the exhaust rate of the vacuum pump.

[0058] The exhaust bypass can be a conduit with a relatively small diameter, which can be connected in parallel with the vacuum pump through an angle valve and communicated with the coating chamber 100. When the precursor is injected into the reaction chamber, the vacuum pump is turned off and the exhaust bypass is opened, so that the exhaust gas is only discharged from the conduit. However, due to the relatively small diameter of the conduit, the intake rate in the reaction chamber will be greater than the exhaust rate, thereby maintaining a relatively high pressure in the reaction chamber.

[0059] When the purge gas is charged into the reaction chamber, the vacuum pump can be turned on to improve the pumping efficiency and the cleaning efficiency of the precursor. When the vacuum pump is turned on, the exhaust bypass can also be closed to prevent the tube with a smaller diameter from being blocked after a long period of work. Compared with setting a butterfly valve, setting an exhaust bypass to achieve adjustable pumping rate is less costly.

[0060] Obviously, in other embodiments, an electric control device may be provided to adjust the power of the vacuum pump, thereby achieving the purpose of adjustable exhaust rate.

[0061] Please refer again Figure 2 In this embodiment, the inner cavity 110 includes a first straight tube section 111, a second straight tube section 112 and a tapered tube section 113. The inner diameter of the first straight tube section 111 is smaller than the inner diameter of the second straight tube section 112, and the first straight tube section 111 and the second straight tube section 112 are respectively connected to the small end and the large end of the tapered tube section 113, and the air inlet port and the air outlet port are respectively provided in the first straight tube section 111 and the second straight tube section 112, and the powder to be coated can be contained in the first straight tube section 111.

[0062] The first straight pipe section 111, the second straight pipe section 112 and the tapered pipe section 113 can be integrally formed and connected by welding. At this time, in the direction from the air inlet port to the air outlet port, the area of ​​the flow end surface of the inner cavity 110 increases in a step-like manner. Among them, the small-diameter first straight pipe section 111 is used to place powder, so that the powder can obtain a higher initial velocity during fluidization.

[0063] The diameter of the conical tube section 113 gradually increases, so the gas flow rate entering the conical tube section 113 will gradually decrease, and the pressure drop of the powder or is gradually reduced. Therefore, it can avoid the sudden settling of the raised powder, thereby reducing the interaction between the powder particles. The second straight tube section 112 with a large diameter provides a buffer space for the powder particles to splash, thereby further avoiding the blockage of the gas outlet port or the adsorption of a large amount of powder on the filter screen of the gas outlet port.

[0064] It should be noted that, in other embodiments, the inner cavity 110 may also be a cavity structure formed by splicing a plurality of straight pipe sections with successively increasing or decreasing diameters. In addition, the inner cavity 110 may also be a conical hollow structure as a whole, with the air inlet port located at the small end and the air outlet port located at the large end. In this case, in the direction from the air inlet port to the air outlet port, the area of ​​the flow end surface of the inner cavity 110 is in a continuous increasing trend.

[0065] Furthermore, in this embodiment, the cone angle of the cone tube section 113 is 30 to 85 degrees. Experimental verification shows that when the cone angle of the cone tube section 113 is between 30 and 85 degrees, the powder has a better dispersion effect and a lower probability of hitting the gas outlet port.

[0066] The commonly used dimensions of the inner cavity 110 are as follows: the diameter d of the first straight tube section 111 is 20 to 100 mm, and the height h1 of the first straight tube section 111 is 10 to 150 mm; the total height h3 of the inner cavity 110 is 50 to 800 mm; the height h2 of the tapered tube section 113 is 30 to 400 mm; the angle α, that is, half of the tapered angle of the tapered tube section 113, is 15 degrees to 45 degrees.

[0067] At this size, when the total intake air flow rate is 100sccm~50slm, according to Figure 3 From the simulation of the air flow velocity distribution in the inner cavity 110 shown, it can be seen that the air flow velocity is high in the first conical tube section 111, while the air flow velocity in the second straight tube section 112 drops sharply.

[0068] Please refer again Figure 1 In this embodiment, the coating chamber 100 further includes an outer chamber 120, the inner chamber 110 is accommodated in the outer chamber 120, and the gas outlet port is connected to the outer chamber 120, and an exhaust port is formed at one end of the outer chamber 120 away from the gas outlet port.

[0069] The outer cavity 120 is generally cylindrical and is coaxially arranged with the inner cavity 110. The exhaust mechanism 400 in this embodiment is connected to the exhaust port, and exhausts the inner cavity 110 by directly exhausting the outer cavity 120. On the one hand, the outer cavity 120 can protect and keep the inner cavity 110 warm; on the other hand, the exhaust mechanism 400 is not directly connected to the outlet port of the inner cavity 110, and the outlet port is far away from the exhaust port. Therefore, it can effectively prevent the powder in the inner cavity 110 from being sucked into the exhaust mechanism 400.

[0070] In addition, a cavity door 121 is provided at one side end of the outer cavity 120 to facilitate the placement and removal of the inner cavity 110 .

[0071] In this embodiment, the coating chamber 100 further includes a vibration mechanism 130 that can drive the inner chamber 110 to vibrate. The vibration mechanism 130 can assist in dispersing the powder particles by generating mechanical vibration, thereby reducing the powder adsorption on the inner wall of the inner chamber 110 and the filter screen of the air outlet port, thereby effectively improving the uniform deposition effect of a large number of powder particles.

[0072] It should be noted that, in other embodiments, the powder particles may be dispersed by stirring, rotating, or the like.

[0073] Furthermore, in this embodiment, the vibration mechanism 130 can drive the inner cavity 110 to vibrate relative to the outer cavity 120. The vibration mechanism 130 includes a vibration source 131, a connecting rod 132 and a bellows 133.

[0074] The vibration source 131 is used to generate vibration energy, and can be a vibration generating device such as a vibration motor, a pneumatic vibrator, an ultrasonic vibration rod, etc. The vibration source 131 is arranged on the outside of the outer cavity 120, and is connected to the inner cavity 110 through a connecting rod 132, and transmits the vibration energy generated by the vibration source 131 to the inner cavity 110. Specifically, the connecting rod 132 is penetrated through the outer cavity 120, and the two ends are respectively fixedly connected to the outer wall of the inner cavity 110 and the vibration source 131. The bellows 133 is sleeved on the connecting rod 132, and the two ends of the bellows 133 are respectively sealed and connected to the outer wall of the inner cavity 110 and the inner wall of the outer cavity 120. In this way, a closed space can be formed between the inner cavity 110, the outer cavity 120 and the bellows 133, thereby avoiding the vacuum of the entire coating cavity 100 from being destroyed due to the gap at the junction of the connecting rod 132 and the outer cavity 120.

[0075] The powder coating device 10 and the coating chamber 100 are filled with fluidizing gas from the air inlet port, so that the powder can obtain a higher initial velocity and fluidize. Since the area of ​​the flow cross section of the inner cavity 110 tends to increase in the direction from the air inlet port to the air outlet port. According to the fluid equation, the gas flow rate in the direction from the air inlet port to the air outlet port will show a decreasing trend. When the flow rate drops to a certain level, the lifted powder will gradually begin to settle and be lifted again when it approaches the air inlet port. Therefore, the powder will form an internal circulation within a limited height, thereby increasing the interaction between the powder particles and reducing agglomeration. At the same time, since the height of the powder lifting is limited, the powder can be prevented from touching and adsorbing on the air outlet port. Moreover, the powder forming the internal circulation increases the impact on the cavity wall and reduces the powder adsorbed on the cavity wall. Therefore, the uniformity of the coating is significantly improved.

[0076] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A coating chamber, comprising an inner chamber, characterized in that: An air inlet port and an air outlet port are formed at two axial ends of the inner cavity, respectively. The powder to be coated can be accommodated in one end of the inner cavity close to the air inlet port, and in the direction from the air inlet port to the air outlet port, the area of ​​the flow cross section of the inner cavity tends to increase; It also includes an outer cavity, the inner cavity is accommodated in the outer cavity, the gas outlet port is connected to the outer cavity, and an exhaust port is formed at one end of the outer cavity away from the gas outlet port; The inner cavity comprises a first straight pipe section, a second straight pipe section and a tapered pipe section, the inner diameter of the first straight pipe section is smaller than the inner diameter of the second straight pipe section, and the first straight pipe section and the second straight pipe section are respectively connected to the small end and the large end of the tapered pipe section, the air inlet port and the air outlet port are respectively arranged in the first straight pipe section and the second straight pipe section, and the powder to be coated can be contained in the first straight pipe section; The height of the inner cavity is 50 mm to 800 mm, the diameter of the first straight tube section is 20 mm to 100 mm, the height of the first straight tube section is 10 mm to 150 mm, the height of the tapered tube section is 30 mm to 400 mm, and the half cone angle of the tapered tube section is 15 degrees to 45 degrees; The outer cavity is cylindrical and is coaxially arranged with the inner cavity. The exhaust mechanism is connected to the exhaust port and exhausts air from the inner cavity by directly exhausting air from the outer cavity.

2. The coating chamber according to claim 1, characterized in that: Also included is a vibration mechanism capable of driving the inner cavity to vibrate.

3. The coating chamber according to claim 1, characterized in that: Also included is a vibration mechanism capable of driving the inner cavity to vibrate relative to the outer cavity, the vibration mechanism comprising: Vibration source; A connecting rod is inserted into the outer cavity and has two ends fixedly connected to the outer wall of the inner cavity and the vibration source respectively; and The bellows is sleeved on the connecting rod, and the two ends of the bellows are respectively sealed and connected to the outer wall of the inner cavity and the inner wall of the outer cavity.

4. A powder coating device, characterized in that: include: The coating chamber according to any one of claims 1 to 3; An air circuit system, connected to the air inlet port and used to fill the inner cavity with gas; A heating system, used for heating the coating chamber and the gas path system; and The exhaust mechanism is connected to the coating cavity and exhausts air from the inner cavity through the air outlet port.

5. The powder coating device according to claim 4, characterized in that: It also includes an exhaust gas treatment mechanism disposed between the exhaust mechanism and the coating chamber.

6. The powder coating device according to claim 4, characterized in that: The suction rate of the suction mechanism for sucking air from the inner cavity is adjustable.

7. The powder coating device according to claim 6, characterized in that: The vacuum mechanism includes a vacuum pump and a butterfly valve arranged between the vacuum pump and the coating chamber.

8. The powder coating device according to claim 7, characterized in that: The exhaust mechanism comprises a vacuum pump and an exhaust bypass which is connected in parallel with the vacuum pump and can be opened or closed. The exhaust rate of the exhaust bypass is lower than the exhaust rate of the vacuum pump.

Images