Powder stage treatment system device and process method

Abstract

The invention provides a powder staged treatment system device and a process method. The grading treatment system device comprises a grading device and a conveying device; the grading device comprises a first-stage vibration screening device, a second-stage vibration screening device and a wind power separation device which are connected in sequence in the powder moving direction; the first-stage vibration screening device and the second-stage vibration screening device are each internally provided with an annular ultrasonic vibration net cleaning device and a gas power device. And the conveying device is used for conveying the graded powder and then acts on a target object. By combining mechanical classification, pneumatic classification, wind power separation and ultrasonic vibration net cleaning technologies, accurate classification of powder is achieved, the requirements for narrow granularity and high boundary precision of ultrafine particle size distribution are met, meanwhile, the powder particles are complete in morphology in the screening process, and efficient conveying is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy, and relates to a powder classification processing system device and a process method. Background Art

[0002] With the development of powder preparation technology and the increasing application of powder in various fields, it is often necessary to achieve quantitative powder delivery of powder. In the field of thermal spraying, the particle size and morphology of powder particles have a crucial impact on the quality of the coating. With the rise of nanopowder materials, the powders currently used in thermal spraying have also become fine (ultrafine powders formed by the agglomeration of nanomaterial particles are usually in the range of 5-30μm). Fine powders are conducive to forming the special functions required by the coating and the smooth morphology of the coating surface, but the traditional powder screening method is difficult to simultaneously meet the narrow particle size and high boundary accuracy of the ultrafine particle size distribution, and the powder particle morphology is easily destroyed during the screening process, and the net is easily blocked during classification. During transportation, ultrafine powders are easy to bridge, compact, agglomerate, and block powder in the powder feeder, causing powder transportation interruption, affecting the stability of the spraying process, and causing uneven coating. In addition, ultrafine powders are easy to be affected by moisture or generate electrostatic agglomeration due to their fine particle size and high activity, which will increase the difficulty of transportation and spraying. Therefore, an effective powder classification and transportation method is needed to solve the above problems.

[0003] In the prior art, powder classification is usually carried out by a single mechanical screening or wind classification method. For example, patent CN221335435U adopts a single wind classification method for classification. This scheme is difficult to obtain powders with narrow particle size distribution and high sphericity, and the patent does not involve powder transportation. Patent CN114538142A adopts a mechanical vibration screening method, which can reduce the particle size range of ultrafine powder particles to 23-45μm to a certain extent, but the advantages of screening and conveying functions for finer ultrafine powders (5-30μm range) are not obvious. At the same time, during the powder transportation process, the powder is easy to adhere to the inner wall of the conveying pipe and the spray gun, causing blockage. In addition, the traditional vibration screening equipment has the phenomenon of network blocking, which reduces the classification efficiency and accuracy. Patent CN109530710A combines airflow classification with mechanical classification to classify powders, mainly for metal powders, and the classification only distinguishes some ultrafine powders (1-20μm) from conventional particle size powders. The classification degree does not meet the narrow particle size and high boundary accuracy requirements of thermal spray ultrafine powders (1-30μm), and the classification boundary of powders in the range of 20-53μm is not clear. In addition, there are also ways to use pneumatic powder feeding or vacuum powder feeding, which can effectively solve the problems of powder agglomeration and easy agglomeration, but these devices are generally large in size, and ultrafine powders are easy to adhere to the inner wall of the equipment, resulting in large weight loss and need to be improved.

[0004] Therefore, how to simultaneously meet the narrow particle size and high boundary accuracy of ultrafine particle size distribution, and how to prevent the powder particle morphology from being easily destroyed during the screening process, so as to achieve accurate classification and efficient transportation, is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a powder classification system and process method. The present invention combines mechanical classification, pneumatic classification, wind separation and ultrasonic vibration cleaning technology to achieve accurate classification of powders, meet the requirements of narrow particle size and high boundary accuracy of ultrafine particle size distribution, and at the same time, the powder particle morphology is complete during the screening process, which is conducive to efficient transportation.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a powder classification processing system device, wherein the classification processing system device comprises a classification device and a conveying device.

[0008] The grading device comprises a primary vibration screening device, a secondary vibration screening device and a wind separation device which are connected in sequence along the direction of powder movement; the primary vibration screening device and the secondary vibration screening device are respectively provided with a ring-shaped ultrasonic vibration cleaning device and a gas power device.

[0009] The conveying device is used to convey the classified powder and then act on the target object.

[0010] The present invention realizes accurate classification of powder by combining mechanical classification, pneumatic classification, wind separation and ultrasonic vibration cleaning technology, meets the requirements of narrow particle size and high boundary accuracy of ultrafine particle size distribution, and at the same time, the powder particle morphology is complete during the screening process, which is conducive to efficient transportation.

[0011] Preferably, the primary vibration screening device comprises a feeding powder hopper and a primary screen along the powder movement direction, and the primary screen is used for preliminarily separating powders with a particle size ≥ 38 μm.

[0012] Preferably, the primary vibration screening device is connected to a first powder storage tank via a first lateral pipeline, and is used to store powder with a particle size ≥ 38 μm after preliminary separation.

[0013] Preferably, the feeding powder hopper is connected to the gas power device through a side air supply pipeline, which is used to provide wind power for screening of the powder, and is recorded as a first gas power device.

[0014] Preferably, the lower end of the primary screen is connected to a first support ring, a first base is provided on the outer side of the first support ring, and the annular ultrasonic vibration screen cleaning device is provided on the inner side of the first support ring, and the annular ultrasonic vibration screen cleaning device is an annular ultrasonic generator.

[0015] Preferably, the mechanical vibration of the primary screen is annular vibration, and the vibration frequency of the annular vibration is 150-300 Hz.

[0016] Preferably, the vibration cleaning frequency of the annular ultrasonic vibration cleaning device in the primary vibration screening device is 20-30KHz.

[0017] Preferably, the first-stage vibrating screening device further comprises a first sealing cover, which is arranged around the outside of the feed powder hopper and the first-stage screen to isolate the dust generated during the screening process from spilling out.

[0018] Preferably, the powder feeding hopper conveys powder to the primary screen for screening through a first powder leakage pipeline.

[0019] Preferably, a plurality of first drainage holes are provided between the first powder leakage pipe and the primary screen, for uniformly screening the powder on the primary screen.

[0020] Preferably, butterfly valves are provided on both the first powder leakage pipeline and the air supply pipeline.

[0021] Preferably, the secondary vibration screening device includes a first powder collector and a secondary sieve along the powder movement direction, the first powder collector is used to collect powder with a particle size of less than 38μm after screening by the first sieve, and the secondary sieve is used to separate powder with a particle size in the range of 23-38μm.

[0022] Preferably, the secondary vibration screening device is connected to a second powder storage tank via a second side pipe, for storing separated powders with a particle size in the range of 23-38 μm.

[0023] Preferably, the lower end of the secondary screen is connected to a second support ring, a second base is provided on the outer side of the second support ring, and the annular ultrasonic vibration screen cleaning device is provided on the inner side of the second support ring. The annular ultrasonic vibration screen cleaning device is an annular ultrasonic generator.

[0024] Preferably, the mechanical vibration of the secondary screen is annular vibration, and the vibration frequency of the annular vibration is 150-300 Hz.

[0025] Preferably, the vibration cleaning frequency of the annular ultrasonic vibration cleaning device in the secondary vibration screening device is 20-30KHz.

[0026] Preferably, the secondary vibration screening device further comprises a second sealing cover, which is arranged around the first powder collector and the outside of the secondary screen to isolate the dust generated during the screening process from spilling out.

[0027] Preferably, the second sealing cover is connected to the second powder storage tank through the second side pipe.

[0028] Preferably, the second sealing cover is connected to the gas power device through a gas delivery pipeline, and is used to provide wind power for powder screening, which is recorded as a second gas power device.

[0029] Preferably, the first powder collector transports powder to the secondary screen for screening through the second powder leakage pipeline.

[0030] Preferably, a plurality of second drainage holes are provided between the second powder leakage pipe and the secondary screen for uniform screening of the powder on the secondary screen.

[0031] Preferably, the second powder leakage pipeline and the gas delivery pipeline are both provided with butterfly valves.

[0032] Preferably, the wind separation device includes a second powder collector and a cyclone separator connected in sequence along the direction of powder movement, the second powder collector is used to collect powder with a particle size of less than 23 μm after screening by the secondary sieve, and the cyclone separator is used to separate powder with a particle size in the range of 1-23 μm.

[0033] Preferably, the second powder collector and the cyclone separator are connected by a third powder leakage pipe, one end of the third powder leakage pipe is connected to the powder outlet of the second powder collector, and the other end is connected to the powder inlet of the cyclone separator, and the powder inlet is arranged on the upper end side of the cyclone separator.

[0034] Preferably, the upper end of the cyclone separator is connected to the second gas power device for recovering gas, and the lower end of the cyclone separator is connected to a third powder storage tank for storing powder with a particle size in the range of 1-23 μm.

[0035] Preferably, a filter is provided between the cyclone separator and the second gas power device for filtering powder with a particle size of less than 1 μm.

[0036] Preferably, a butterfly valve is provided on the third powder leakage pipeline.

[0037] Preferably, the grading device further comprises a PLC controller, and the PLC controller is used to control the operation of the grading processing system device.

[0038] Preferably, the conveying device comprises:

[0039] A conveying pipeline is used to convey powder to the thermal spraying device for spraying.

[0040] A mass flow meter is used to control the process parameters of conveying carrier gas.

[0041] An ultrasonic pulse vibration device is located on the outer side wall of the conveying pipeline and close to the powder outlet of the conveying pipeline, and is used to keep the powder in a suspended atomized state in the conveying pipeline.

[0042] Preferably, the conveying pipe is made of antistatic material to reduce the adhesion of powder to the inner wall.

[0043] In a second aspect, the present invention provides a process for grading and conveying powders, the process being carried out in the grading system device as described in the first aspect, and comprising the following steps:

[0044] The original powder to be screened is passed through a primary vibration screening device, a secondary vibration screening device and a wind separation device to screen the powders with different particle size distribution ranges.

[0045] The powder obtained after screening is transported through a conveying device and then acts on the target object.

[0046] Preferably, the process comprises the following steps:

[0047] (1) The raw powder to be screened is loaded into the feed powder hopper, and then enters the primary sieve with a mesh size of 400 for vibration screening. After screening, the powder with a particle size ≥ 38 μm enters the first powder storage tank, and the powder with a particle size < 38 μm passes through the primary sieve and enters the first powder collector.

[0048] The original powder includes any one of metal ceramic powder, alloy metal powder or metal oxide ceramic powder or a combination of at least two thereof, and the particle size distribution range of the original powder is 1-150 μm.

[0049] (2) The powder in the first powder collector enters a secondary sieve with a mesh size of 600 for vibration screening. After screening, the powder with a particle size in the range of 23-38 μm enters the second powder storage tank, while the powder with a particle size of less than 23 μm passes through the secondary sieve and enters the second powder collector.

[0050] (3) The powder in the second powder collector enters the cyclone separator through the third powder leakage pipe. With the help of centrifugal force and resistance, the powder with a particle size of 1-23 μm is precipitated and collected in the third powder storage tank, while the crushed powder with a particle size of less than 1 μm is filtered through the filter with the flow of gas and remains in the filter screen of the filter. The gas passing through the filter is returned to the second gas power device for recovery and reused for auxiliary classification of the powder.

[0051] However, it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] The present invention realizes accurate classification of powder by combining mechanical classification, pneumatic classification, wind separation and ultrasonic vibration cleaning technology, meets the requirements of narrow particle size and high boundary accuracy of ultrafine particle size distribution, and at the same time, the powder particle morphology is complete during the screening process, which is conducive to efficient transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic structural diagram of the grading device provided by the present invention.

[0056] Among them, 1-feed powder hopper; 2-first level screen; 3-first side pipeline; 4-first powder storage tank; 5-side air supply pipeline; 6-air supply fan room; 7-air supply fan; 8-first support ring; 9-first base; 10-first annular ultrasonic generator; 11-first sealing cover; 12-first powder leakage pipeline; 13-first drainage hole; 14-first butterfly valve; 15-second butterfly valve; 16-first powder collector; 17-second level screen; 18-second side pipeline; 19-second powder storage tank ; 20-second support ring; 21-second base; 22-second annular ultrasonic generator; 23-second sealing cover; 24-gas delivery pipeline; 25-air supply chamber; 26-air blower; 27-second powder leakage pipeline; 28-second drainage hole; 29-third butterfly valve; 30-fourth butterfly valve; 31-second powder collector; 32-cyclone separator; 33-third powder leakage pipeline; 34-powder outlet; 35-third powder storage tank; 36-filter; 37-fifth butterfly valve; 38-PLC controller. DETAILED DESCRIPTION

[0057] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are 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 on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0058] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0059] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0060] In a specific embodiment, the present invention provides a powder classification processing system device, and the classification processing system device includes a classification device and a conveying device.

[0061] like Figure 1 As shown, the grading device includes a primary vibration screening device, a secondary vibration screening device and a wind separation device connected in sequence along the direction of powder movement; the primary vibration screening device and the secondary vibration screening device are each provided with a ring-shaped ultrasonic vibration cleaning device and a gas power device.

[0062] The conveying device is used to convey the classified powder and then act on the target object.

[0063] The present invention realizes accurate classification of powder by combining mechanical classification, pneumatic classification, wind separation and ultrasonic vibration cleaning technology, meets the requirements of narrow particle size and high boundary accuracy of ultrafine particle size distribution, and at the same time, the powder particle morphology is complete during the screening process, which is conducive to efficient transportation.

[0064] Furthermore, the primary vibration screening device includes a feeding powder hopper 1 and a primary screen 2 along the powder movement direction, and the primary screen 2 is used for preliminarily separating powders with a particle size ≥ 38 μm, such as powders with a particle size distribution range of 38-150 μm.

[0065] It should be noted that the present invention uses a laser particle size analyzer to detect the particle size of the classified powder. The same applies to the following.

[0066] Furthermore, the mesh size of the primary sieve 2 is 400 meshes.

[0067] Furthermore, the primary vibration screening device is connected to the first powder storage tank 4 via the first lateral pipeline 3, and is used to store powder with a particle size of ≥38 μm after preliminary separation.

[0068] Furthermore, the feeding powder hopper 1 is connected to the gas power device through a side air supply pipeline 5, which is used to provide wind power for powder screening, and is recorded as a first gas power device.

[0069] It should be noted that the gas power device provides wind power to drive the gas in the gas storage tank connected to the gas power device to flow, thereby providing assistance for the screening of the powder. The same applies to the following.

[0070] Furthermore, the first gas power device comprises an air supply fan chamber 6 , in which an air supply fan 7 is arranged, and the air supply fan 7 provides power for gas flow.

[0071] Furthermore, the lower end of the primary screen 2 is connected to a first support ring 8, a first base 9 is provided on the outer side of the first support ring 8, and the inner side of the first support ring 8 is provided with the annular ultrasonic vibration screen cleaning device, which is an annular ultrasonic generator, recorded as a first annular ultrasonic generator 10.

[0072] In the present invention, the base is driven by a vibration machine to generate vibration, and the base transmits the vibration to the primary screen 2 with the first support ring 8, so that the primary screen 2 generates annular mechanical vibration, and adopts a three-dimensional motion trajectory of up and down, front and back, and left and right to achieve mechanical vibration screening.

[0073] In the present invention, the high-frequency vibration of the annular ultrasonic generator causes the screen to generate high-frequency micro-vibration, which is beneficial to preventing powder particles from blocking the screen holes and improving the continuity and efficiency of the screening process.

[0074] Furthermore, the mechanical vibration of the primary screen 2 is annular vibration, and the vibration frequency of the annular vibration is 150-300 Hz, for example, it can be 150 Hz, 200 Hz, 250 Hz or 300 Hz.

[0075] Furthermore, the vibration cleaning frequency of the annular ultrasonic vibration cleaning device in the primary vibration screening device is 20-30KHz, for example, it can be 20KHz, 22KHz, 24KHz, 26KHz, 28KHz or 30KHz.

[0076] Furthermore, the first-stage vibrating screening device also includes a first sealing cover 11, which is arranged around the outside of the feeding powder hopper 1 and the first-stage screen 2 to isolate the dust generated during the screening process from spilling out.

[0077] In the present invention, the first sealing cover 11 can ensure the sealing of the primary screening, which is beneficial to ensure the cleanliness of the screening environment and prevent external impurities from mixing in to a certain extent, thereby ensuring the purity and stability of the screening work.

[0078] Furthermore, the powder feeding hopper 1 conveys powder to the primary screen 2 for screening through the first powder leakage pipeline 12 .

[0079] Furthermore, a plurality of first drainage holes 13 are provided between the first powder leakage pipe 12 and the primary screen 2 for uniformly screening the powder on the primary screen 2 .

[0080] In the present invention, a plurality of first drainage holes 13 are evenly distributed above the primary screen 2 to form a laminar flow, so that the powder to be screened passes through the primary screen 2 from top to bottom.

[0081] Furthermore, the first powder leakage pipeline 12 and the air supply pipeline are both provided with butterfly valves, which are a first butterfly valve 14 and a second butterfly valve 15 respectively.

[0082] Furthermore, the secondary vibration screening device includes a first powder collector 16 and a secondary sieve 17 along the powder movement direction, the first powder collector 16 is used to collect powders with a particle size of less than 38μm after screening by the first sieve 2, and the secondary sieve 17 is used to separate powders with a particle size in the range of 23-38μm, for example, powders with particle sizes of 23μm, 23μm, 26μm, 29μm, 32μm, 35μm or 38μm.

[0083] Furthermore, the first powder collector 16 is a first powder hopper collector.

[0084] Furthermore, the mesh size of the secondary sieve 17 is 600 meshes.

[0085] Furthermore, the secondary vibration screening device is connected to a second powder storage tank 19 via a second lateral pipeline 18, and is used to store separated powders with a particle size in the range of 23-38 μm.

[0086] Furthermore, the lower end of the secondary screen 17 is connected to a second support ring 20, a second base 21 is arranged on the outer side of the second support ring 20, and the inner side of the second support ring 20 is provided with the annular ultrasonic vibration screen cleaning device, which is an annular ultrasonic generator, denoted as a second annular ultrasonic generator 22, and is used to drive the second base 21 to generate vibration, which is then transmitted to the secondary screen 17.

[0087] In the present invention, the base is driven by a vibrating machine to generate vibration, and the base transmits the vibration to the secondary screen 17 with the second support ring 20, so that the secondary screen 17 generates annular mechanical vibration, and adopts a three-dimensional motion trajectory of up and down, front and back, and left and right to achieve mechanical vibration screening.

[0088] In the present invention, the high-frequency vibration of the annular ultrasonic generator causes the screen to generate high-frequency micro-vibration, which is beneficial to preventing powder particles from blocking the screen holes and improving the continuity and efficiency of the screening process.

[0089] Furthermore, the mechanical vibration of the secondary screen 17 is annular vibration, and the vibration frequency of the annular vibration is 150-300 Hz, for example, it can be 150 Hz, 200 Hz, 250 Hz or 300 Hz.

[0090] Furthermore, the vibration cleaning frequency of the annular ultrasonic vibration cleaning device in the secondary vibration screening device is 20-30KHz, for example, it can be 20KHz, 22KHz, 24KHz, 26KHz, 28KHz or 30KHz.

[0091] Furthermore, the secondary vibration screening device also includes a second sealing cover 23, which is arranged around the first powder collector 16 and the secondary screen 17 to isolate the dust generated during the screening process from spilling out.

[0092] In the present invention, the second sealing cover 23 can ensure the sealing of the secondary screening, which is beneficial to ensure the cleanliness of the screening environment and prevent external impurities from mixing in to a certain extent, thereby ensuring the purity and stability of the screening work.

[0093] Furthermore, the second sealing cover 23 is connected to the second powder storage tank 19 through the second lateral pipeline 18 .

[0094] Furthermore, the second sealing cover 23 is connected to the gas power device through a gas delivery pipeline 24, and is used to provide wind power for powder screening, which is recorded as a second gas power device.

[0095] Furthermore, the second gas power device includes an air supply chamber 25, and a blower 26 is disposed in the air supply chamber 25, and the blower 26 provides power for the gas flow.

[0096] Furthermore, the first powder collector 16 transports powder to the secondary screen 17 through the second powder leakage pipeline 27 for screening.

[0097] Furthermore, the second powder leakage pipeline 27 is a hose.

[0098] Furthermore, a plurality of second drainage holes 28 are provided between the second powder leakage pipe 27 and the secondary screen 17 for uniformly screening the powder on the secondary screen 17 .

[0099] In the present invention, a plurality of second drainage holes 28 are evenly distributed above the secondary screen 17 to form a laminar flow, so that the powder passes through the secondary screen 17 from top to bottom.

[0100] Furthermore, the second powder leakage pipeline 27 and the gas delivery pipeline 24 are both provided with butterfly valves, which are the third butterfly valve 29 and the fourth butterfly valve 30 respectively.

[0101] Furthermore, the wind separation device includes a second powder collector 31 and a cyclone separator 32 connected in sequence along the direction of powder movement, the second powder collector 31 is used to collect powders with a particle size of less than 23 μm after screening by the secondary sieve 17, and the cyclone separator 32 is used to separate powders with a particle size in the range of 1-23 μm, for example, powders with particle sizes of 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 22 μm or 23 μm.

[0102] Furthermore, the second powder collector 31 and the cyclone separator 32 are connected via a third powder leakage pipe 33, one end of the third powder leakage pipe 33 is connected to the powder outlet 34 of the second powder collector 31, and the other end is connected to the powder inlet of the cyclone separator 32, and the powder inlet is arranged on the upper end side of the cyclone separator 32.

[0103] Furthermore, the third powder leakage pipeline 33 is a hose.

[0104] Furthermore, the upper end of the cyclone separator 32 is connected to the second gas power device for recovering gas, and the lower end of the cyclone separator 32 is connected to the third powder storage tank 35 for storing powder with a particle size in the range of 1-23 μm.

[0105] Furthermore, a filter 36 is provided between the cyclone separator 32 and the second gas power device for filtering powder with a particle size of less than 1 μm.

[0106] It should be noted that the powder with a particle size less than 1 μm is filtered out. The powder with this particle size is not usable in the thermal spraying process, and therefore does not flow into the powder storage tank but is retained in the filter screen of the filter 36 .

[0107] Furthermore, a butterfly valve is provided on the third powder leakage pipeline 33. Exemplarily, a fifth butterfly valve 37 is provided at the powder outlet 34 of the third powder leakage pipeline 33 close to the second powder collector 31 and close to the powder inlet of the cyclone separator 32.

[0108] Furthermore, in the cyclone separator 32, the air flow rate is 10-20 m / s, for example, it can be 10 m / s, 15 m / s or 20 m / s.

[0109] Furthermore, the grading device further comprises a PLC controller 38 (Programmable Logic Controller), and the PLC controller 38 is used to control the operation of the grading processing system device.

[0110] Furthermore, the conveying device comprises:

[0111] A conveying pipeline is used to convey powder to the thermal spraying device for spraying.

[0112] A mass flow meter is used to control the process parameters of the carrier gas. For example, the carrier gas may be nitrogen or argon.

[0113] An ultrasonic pulse vibration device is located on the outer wall of the conveying pipeline and close to the powder outlet 34 of the conveying pipeline, and is used to keep the powder in a suspended atomized state in the conveying pipeline.

[0114] In the present invention, the mass flow meter can be used to accurately control the flow rate, pressure and flow rate of the carrier gas, thereby maintaining uniform powder delivery and avoiding blockage.

[0115] In the present invention, an ultrasonic pulse vibration device is used to keep the powder in a suspended atomized state in the conveying pipeline, thereby preventing aggregation and avoiding blockage.

[0116] The structure of the conveying device provided by the present invention can reduce powder adhesion, prevent powder aggregation, ensure stable powder delivery, avoid problems such as spray gun clogging, and improve the efficiency and reliability of the thermal spraying process.

[0117] Furthermore, the conveying pipe is made of antistatic material to reduce the adhesion of powder to the inner wall.

[0118] Furthermore, the antistatic material includes polytetrafluoroethylene.

[0119] It should be noted that the inner wall of the conveying pipe provided by the present invention is smooth, which is beneficial to reducing the adhesion of powder to the inner wall.

[0120] Furthermore, the pressure of the carrier gas is 0.4-0.8 MPa, for example, it can be 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa or 0.8 MPa.

[0121] Furthermore, the frequency of the ultrasonic pulse vibration device is 20-30KHz, for example, it can be 20KHz, 22KHz, 24KHz, 26KHz, 28KHz or 30KHz.

[0122] In another specific embodiment, the present invention provides a process for grading and conveying powder, the process comprising the following steps:

[0123] (1) The raw powder to be screened is loaded into the feed powder hopper, and then enters the primary sieve with a mesh size of 400 for vibration screening. After screening, the powder with a particle size ≥ 38 μm enters the first powder storage tank, and the powder with a particle size < 38 μm passes through the primary sieve and enters the first powder collector.

[0124] The original powder includes any one of metal ceramic powder (such as WC-10Co4Cr powder, etc.), alloy metal powder (such as NiCr alloy metal powder, etc.) or metal oxide ceramic powder (such as alumina ceramic powder, etc.) or a combination of at least two of them, and the particle size distribution range of the original powder is 1-150 μm.

[0125] (2) The powder in the first powder collector enters a secondary sieve with a mesh size of 600 for vibration screening. After screening, the powder with a particle size in the range of 23-38 μm enters the second powder storage tank, while the powder with a particle size of less than 23 μm passes through the secondary sieve and enters the second powder collector.

[0126] (3) The powder in the second powder collector enters the cyclone separator through the third powder leakage pipe. With the help of centrifugal force and resistance, the powder with a particle size of 1-23 μm is precipitated and collected in the third powder storage tank, while the crushed powder with a particle size of less than 1 μm is filtered through the filter with the flow of gas and remains in the filter screen of the filter. The gas passing through the filter is returned to the second gas power device for recovery and reused for auxiliary classification of the powder.

[0127] Example

[0128] This embodiment provides a process for grading and conveying powder, comprising the following steps:

[0129] (1) Primary classification of powder:

[0130] The original powder to be screened is loaded into the feed powder hopper, and then driven by argon gas enters the first-level sieve with a mesh size of 400 for vibration screening. The first-level sieve adopts a three-dimensional vibration motion mode of front and back, up and down, left and right, and the vibration frequency is 200Hz. After screening, the powder with a particle size ≥38μm enters the first powder storage tank, and the powder with a particle size <38μm passes through the first-level sieve and enters the first powder collector.

[0131] Wherein, the original powder is WC-10Co4Cr powder, etc., and the particle size distribution range of the original powder is 1-150 μm; the vibration cleaning frequency of the annular ultrasonic generator is 25 KHz.

[0132] (2) Secondary classification of powder:

[0133] Driven by argon gas, the powder in the first powder collector enters the secondary sieve with a mesh size of 600 for vibration screening. The secondary sieve adopts a three-dimensional vibration motion mode of front and back, up and down, left and right, and the vibration frequency is 200Hz. After screening, the powder with a particle size in the range of 23-38μm enters the second powder storage tank, and the powder with a particle size of less than 23μm passes through the secondary sieve and enters the second powder collector.

[0134] (3) Wind classification of powder:

[0135] The powder in the second powder collector enters the cyclone separator through the third powder leakage pipe, and the air flow rate is adjusted to 15m / s. With the help of centrifugal force and resistance, the powder with a particle size in the range of 1-23μm is settled and collected in the third powder storage tank, while the crushed powder with a particle size of less than 1μm is filtered through the filter with the flow of argon gas and remains in the filter screen of the filter, and the argon gas passing through the filter is returned to the second gas power device for recovery and reused for auxiliary classification of powders.

[0136] (4) Powder transportation:

[0137] The powder in the third powder storage tank is transported to the spray gun end through a transport pipeline for subsequent thermal spraying.

[0138] The carrier gas in the delivery pipeline is argon, the flow rate of argon is 5m / s, and the pressure is 0.6MPa; the frequency of the ultrasonic pulse vibration device is 25KHz.

[0139] In summary

[0140] The powder in the third powder storage tank was tested using a laser particle size analyzer. The test results showed that the particle size distribution of the powder was between 10-20 μm, D50 was 15 μm, and the particle size distribution was narrow.

[0141] The powder delivered to the spray gun end of the above embodiment was subjected to a thermal spraying process, i.e., thermal spraying was performed using a plasma gun. It was found that no spray gun blockage occurred during the spraying process, and the powder delivery was stable. In addition, the coating formed after spraying was tested for microhardness, bonding strength and surface roughness. The test results showed that the coating was dense, had high hardness, and had a uniform surface, and met the use requirements.

[0142] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A powder classification processing system device, characterized in that: The grading system device comprises a grading device and a conveying device; The grading device includes a primary vibration screening device, a secondary vibration screening device and a wind separation device connected in sequence along the direction of powder movement; the primary vibration screening device and the secondary vibration screening device are respectively provided with a ring-shaped ultrasonic vibration cleaning device and a gas power device; The conveying device is used to convey the classified powder and then act on the target object.

2. The grading system device according to claim 1, characterized in that: The first-stage vibrating screening device includes a feeding powder hopper and a first-stage screen along the powder movement direction, and the first-stage screen is used for preliminarily separating powders with a particle size of ≥38 μm; Preferably, the primary vibration screening device is connected to the first powder storage tank via a first side pipe, for storing powder with a particle size of ≥38 μm after preliminary separation; Preferably, the feeding powder hopper is connected to the gas power device through a side air supply pipeline, which is used to provide wind power for powder screening, and is recorded as a first gas power device; Preferably, the lower end of the primary screen is connected to a first support ring, a first base is arranged on the outer side of the first support ring, and the annular ultrasonic vibration screen cleaning device is arranged on the inner side of the first support ring, and the annular ultrasonic vibration screen cleaning device is an annular ultrasonic generator; Preferably, the mechanical vibration of the primary screen is annular vibration, and the vibration frequency of the annular vibration is 150-300 Hz; Preferably, the vibration cleaning frequency of the annular ultrasonic vibration cleaning device in the primary vibration screening device is 20-30KHz.

3. The hierarchical processing system according to claim 2, characterized in that: The first-stage vibrating screening device further includes a first sealing cover, which is disposed around the outside of the feeding powder hopper and the first-stage screen to isolate the dust generated during the screening process from spilling out; Preferably, the feeding powder hopper conveys powder to the primary screen through the first powder leakage pipeline for screening; Preferably, a plurality of first drainage holes are provided between the first powder leakage pipe and the first-level screen, for uniformly screening the powder on the first-level screen; Preferably, butterfly valves are provided on both the first powder leakage pipeline and the air supply pipeline.

4. The classification processing system according to claim 2 or 3, characterized in that: The secondary vibration screening device includes a first powder collector and a secondary screen along the powder movement direction, wherein the first powder collector is used to collect powders with a particle size of less than 38 μm after screening by the first screen, and the secondary screen is used to separate powders with a particle size in the range of 23-38 μm; Preferably, the secondary vibration screening device is connected to a second powder storage tank via a second side pipe, for storing separated powders with a particle size in the range of 23-38 μm; Preferably, the lower end of the secondary screen is connected to a second support ring, a second base is arranged on the outer side of the second support ring, and the annular ultrasonic vibration screen cleaning device is arranged on the inner side of the second support ring, and the annular ultrasonic vibration screen cleaning device is an annular ultrasonic generator; Preferably, the mechanical vibration of the secondary screen is annular vibration, and the vibration frequency of the annular vibration is 150-300 Hz; Preferably, the vibration cleaning frequency of the annular ultrasonic vibration cleaning device in the secondary vibration screening device is 20-30KHz.

5. The hierarchical processing system according to claim 4, characterized in that: The secondary vibration screening device further includes a second sealing cover, which is arranged around the first powder collector and the outside of the secondary screen to isolate the dust generated during the screening process from spilling out; Preferably, the second sealing cover is connected to the second powder storage tank through the second side pipe; Preferably, the second sealing cover is connected to the gas power device through a gas delivery pipeline, and is used to provide wind power for powder screening, which is recorded as a second gas power device; Preferably, the first powder collector transports powder to the secondary screen through the second powder leakage pipeline for screening; Preferably, a plurality of second drainage holes are provided between the second powder leakage pipe and the secondary screen, for uniform screening of the powder on the secondary screen; Preferably, the second powder leakage pipeline and the gas delivery pipeline are both provided with butterfly valves.

6. The classification processing system according to claim 4 or 5, characterized in that: The wind separation device includes a second powder collector and a cyclone separator connected in sequence along the direction of powder movement, wherein the second powder collector is used to collect powders with a particle size of less than 23 μm after screening by the secondary sieve, and the cyclone separator is used to separate powders with a particle size in the range of 1-23 μm; Preferably, the second powder collector and the cyclone separator are connected via a third powder leakage pipeline, one end of the third powder leakage pipeline is connected to the powder outlet of the second powder collector, and the other end is connected to the powder inlet of the cyclone separator, and the powder inlet is arranged at the upper end side of the cyclone separator; Preferably, the upper end of the cyclone separator is connected to the second gas power device for recovering gas, and the lower end of the cyclone separator is connected to a third powder storage tank for storing powder with a particle size in the range of 1-23 μm; Preferably, a filter is provided between the cyclone separator and the second gas power device for filtering powder with a particle size of less than 1 μm; Preferably, a butterfly valve is provided on the third powder leakage pipeline.

7. The grading system device according to any one of claims 1 to 6, characterized in that: The grading device further comprises a PLC controller, and the PLC controller is used to control the operation of the grading processing system device.

8. The grading system device according to any one of claims 1 to 7, characterized in that: The conveying device comprises: A conveying pipeline, wherein the conveying pipeline is used to convey powder to the thermal spraying device for spraying; A mass flow meter, the mass flow meter is used to control the process parameters of the carrier gas delivery; An ultrasonic pulse vibration device, the ultrasonic pulse vibration device is located on the outer side wall of the conveying pipeline and close to the powder outlet of the conveying pipeline, and is used to keep the powder in a suspended atomized state in the conveying pipeline; Preferably, the conveying pipe is made of antistatic material to reduce the adhesion of powder to the inner wall.

9. A process for grading and conveying powder, characterized in that: The process is carried out in a grading treatment system as claimed in any one of claims 1 to 8, and the process comprises the following steps: The original powder to be screened is passed through a primary vibration screening device, a secondary vibration screening device and a wind separation device to screen the powders with different particle size distribution ranges; The powder obtained after screening is transported through a conveying device and then acts on the target object.

10. The process according to claim 9, characterized in that: The process comprises the following steps: (1) The raw powder to be screened is loaded into the feed powder hopper, and then enters the primary sieve with a mesh size of 400 meshes for vibration screening. After screening, the powder with a particle size ≥ 38 μm enters the first powder storage tank, and the powder with a particle size < 38 μm passes through the primary sieve and enters the first powder collector; Wherein, the original powder includes any one of metal ceramic powder, alloy metal powder or metal oxide ceramic powder or a combination of at least two thereof, and the particle size distribution range of the original powder is 1-150 μm; (2) The powder in the first powder collector enters a secondary sieve with a mesh size of 600 for vibration screening. After screening, the powder with a particle size in the range of 23-38 μm enters the second powder storage tank, while the powder with a particle size of less than 23 μm passes through the secondary sieve and enters the second powder collector; (3) The powder in the second powder collector enters the cyclone separator through the third powder leakage pipe. With the help of centrifugal force and resistance, the powder with a particle size of 1-23 μm is precipitated and collected in the third powder storage tank, while the crushed powder with a particle size of less than 1 μm is filtered through the filter with the flow of gas and remains in the filter screen of the filter. The gas passing through the filter is returned to the second gas power device for recovery and reused for auxiliary classification of the powder.

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