Powder fineness measuring device

Abstract

The utility model discloses a powder fineness measuring device which comprises a powder bowl, a bearing frame, an electric cylinder, a screening plate, a blowing assembly and a frame supporting column, the bearing frame is located above a bottom supporting face and connected with the output end of the electric cylinder, the electric cylinder is fixed to the bottom supporting face, the powder bowl is separably placed on the bearing frame, and the screening plate is connected with the blowing assembly. A sealing ring and a plurality of springs are arranged on the lower surface of the screening plate, the blowing assembly comprises a blowing device, a transmission ventilator and a motor, the blowing device is connected with the motor through the transmission ventilator, the motor is fixed to a blowing support, and the blowing support is installed on the upper surface of the screening plate. Meanwhile, the screen is periodically and physically brushed and cleaned through air injection by the purging device, so that the screen is effectively prevented from being blocked, the rolling bearing mounted in the purging bracket can ensure stable and smooth rotation of the assembly, the positive pressure of air on the inner side of a gap can also prevent dust from invading, and the cleanliness of a working environment is effectively ensured.

Description

Technical Field

[0001] This utility model relates to the field of powder measurement technology, specifically a powder fineness measuring device. Background Technology

[0002] Powder fineness measuring devices are widely used in industries such as chemical, pharmaceutical and food to detect the particle size distribution of powders. Existing technologies usually use sieving methods, which separate powders by particle size through sieves and calculate fineness by weighing powders of different particle sizes. However, the powder stirring systems of existing devices mostly rely on simple airflow or vibration methods, resulting in low sieving accuracy.

[0003] In existing technologies, the powder mixing effect is insufficient, making it difficult to effectively disperse large powder particles and affecting sieving efficiency. At the same time, the screen cleaning mechanism is relatively simple and prone to clogging, affecting measurement accuracy. In addition, screen replacement is inconvenient and cannot flexibly adapt to the needs of different particle sizes, limiting the scope of application of the equipment.

[0004] Therefore, this utility model provides a powder fineness measuring device. Utility Model Content

[0005] In view of the shortcomings of the existing technology, this utility model provides a powder fineness measuring device to solve the above problems.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A powder fineness measuring device includes a powder bowl, a support frame, an electric cylinder, a sieve plate, a purging assembly, and a frame support. The frame support rigidly connects the bottom support surface, the middle support surface, and the sieve plate to form an integral support structure. The support frame is located above the bottom support surface and is connected to the output end of the electric cylinder. The electric cylinder is fixed to the bottom support surface and is used to drive the support frame to move vertically. The powder bowl can be detachably placed on the support frame. The lower surface of the sieve plate is provided with a sealing ring and multiple springs. The purging assembly includes a purger, a transmission ventilator, and a motor. The purger is connected to the motor through the transmission ventilator. The motor is fixed to the purging support. The purging support is installed on the upper surface of the sieve plate, and the rotation axis of the purger is aligned with the center hole of the sieve plate.

[0007] Preferably, the screening plate is provided with fine powder discharge holes, coarse powder discharge holes, feed holes, and air inlets. A detachable screen assembly is installed at the fine powder discharge holes, a blower is fixed at the air inlets, and a feed funnel is provided above the feed holes. The fine powder discharge holes and coarse powder discharge holes are connected to the fine powder discharge pipe and coarse powder discharge pipe respectively through right-angle pipe connectors. The two are connected to the discharge pipe one through T-shaped pipe connectors and extend to the cyclone collector. An electromagnetic switch valve one is provided at the feed holes, an electromagnetic switch valve two is provided at the coarse powder discharge holes, and an electromagnetic switch valve three is provided at the fine powder discharge holes to control the opening and closing of each hole.

[0008] Preferably, the blower has small holes on both hemispherical surfaces, a thin brush on one side and a long slot on the other side. The distance between the thin brush and the screen assembly is 3-5 cm. The drive ventilator includes a solid shaft and a hollow tube. The solid shaft is connected to the blower by threads, and the hollow tube is rigidly connected to the solid shaft by a thin plate. Rolling bearing one and rolling bearing two are provided on the outside of the hollow tube. A flat bearing is provided inside the blower bracket to support the lower half of the LM coupling. The lower half of the LM coupling is threadedly connected to the solid shaft of the drive ventilator through a torque transmitter and fixed by a locking nut.

[0009] Preferably, the sealing ring has a thickness of 0.5-1 cm and is fixed to the lower surface of the screening plate by screws. Springs are symmetrically distributed at the four corners of the lower surface of the screening plate, and the compression stroke of each spring is 2-4 cm. The lower surface of the screening plate is also provided with a sealing gasket to enhance the sealing between the screening plate and the purging support.

[0010] Preferably, the electronic scale is fixed on the central support surface and isolated from the support bowl platform by a rubber gasket. The support bowl platform has a circular groove that matches the bottom slot of the powder bowl. The groove depth is 1-2 cm. The detection end of the thermocouple extends into the lower surface of the sieve plate to detect the temperature inside the sealed chamber.

[0011] Preferably, the gas heating tube is connected to the purging bracket through inlet pipe one, inlet pipe two, and inlet pipe three, and the diameter of inlet pipe three is - cm. Blower one and blower two control the gas flow through electromagnetic switch valve one, electromagnetic switch valve two, and electromagnetic switch valve three, respectively. Discharge pipe two and discharge pipe three are connected to cyclone collector and blower two, respectively, for discharging powder in the airflow.

[0012] Preferably, the waste collection bottle is connected to the bottom of the cyclone collector by a thread, and the volume of the waste collection bottle is 500-1000 ml. The air inlet of the cyclone collector is connected to the discharge pipe one, and the air outlet is connected to the blower two through the discharge pipe two. Screening plate connector one, screening plate connector two and screening plate connector three are respectively installed on the screening plate to connect the fine powder discharge hole, the coarse powder discharge hole and the feed hole.

[0013] Preferably, the upper half of the LM coupling is connected to the output shaft of the motor, and the lower half of the LM coupling is connected to the torque transmitter to transmit the torque of the motor. The screening plate is also equipped with rubber pads to reduce the interference of vibration on the electronic scale.

[0014] Beneficial effects

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) Through the designed airflow agitation and screen cleaning components: First, it can generate strong turbulence in the powder bowl, which can fully enhance the powder agitation effect and improve the powder suction capacity; Second, the strong turbulence can disperse large particles, and at the same time, the periodic physical brushing and air jet cleaning of the screen by the blower can effectively prevent the screen from clogging; Finally, the rolling bearing installed in the blower bracket can ensure the stable and smooth rotation of the components, and the positive pressure of the gas inside the gap can also prevent dust from entering, effectively ensuring the cleanliness of the working environment.

[0017] (2) By installing a sealing ring on the lower surface of the sieve plate, the airtightness of the chamber formed by the sieve plate and the powder bowl can be effectively guaranteed, preventing dust from escaping and causing pollution when the airflow is agitated.

[0018] (3) By installing a spring with a certain stiffness on the lower surface of the sieve plate, the powder bowl can be subjected to a certain thrust when pressed with the sieve plate, so as to solve the problem that the powder bowl is difficult to move downward with the support frame and sticks to the sieve plate due to the unidirectional force of the support frame and the stickiness of the sealing ring.

[0019] (4) The screen assembly on the lower surface of the sieve plate can be disassembled and replaced with different apertures as needed to meet different testing requirements. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall content framework of this utility model;

[0021] Figure 2 This is a schematic diagram of the overall structure of this utility model;

[0022] Figure 3 This is a schematic diagram of the lower structure of this utility model;

[0023] Figure 4 This is a schematic diagram of the powder bowl structure of this utility model;

[0024] Figure 5 This is a schematic diagram of the upper structure of this utility model;

[0025] Figure 6 This is a schematic diagram of the screening plate and its lower side layout of the present invention;

[0026] Figure 7 This is an exploded view of the airflow agitation and screen spraying assembly of this utility model.

[0027] In the diagram: 1. Powder bowl; 2. Bowl support platform; 3. Electronic scale; 4. Support frame; 5. Electric cylinder; 6. Bottom support surface; 7. Middle support surface; 8. Frame support column; 9. Air inlet pipe II; 10. Waste collection bottle; 11. Air blower I; 12. Air inlet pipe I; 13. Discharge pipe III; 14. Air blower II; 15. Discharge pipe II; 16. Cyclone collector; 17. Discharge pipe I; 18. Gas heating pipe; 19. Air inlet pipe III; 20. T-shaped pipe connector; 21. Fine powder discharge pipe; 22. Coarse powder discharge pipe; 23. DC motor; 24. Feed funnel; 25. Blowing support; 26. Screening plate; 27. 28. Spring; 29. ​​Blower; 30. Thin brush; 31. Thermocouple; 32. Electromagnetic switch valve one; 33. Screen plate connector one; 34. Rubber gasket; 35. Right-angle pipe connector; 36. Lower half of LM coupling; 37. Upper half of LM coupling; 38. Screen assembly; 39. Drive ventilator; 40. Sealing ring; 41. Sealing gasket; 42. Rolling bearing one; 43. Rolling bearing two; 44. Torque transmitter; 45. Locking nut; 46. Flat bearing; 47. Electromagnetic switch valve two; 48. Screen plate connector two; 49. Electromagnetic switch valve three; 40. Screen plate connector three. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Please see Figures 1-7 A powder fineness measuring device includes a powder bowl 1, a support frame 4, an electric cylinder 5, a sieve plate 26, a purging assembly, and a frame support 8. The frame support 8 rigidly connects the bottom support surface 6, the middle support surface 7, and the sieve plate 26 to form an integral support structure. The support frame 4 is located above the bottom support surface 6 and is connected to the output end of the electric cylinder 5. The electric cylinder 5 is fixed on the bottom support surface 6 and is used to drive the support frame 4 to move in the vertical direction. The powder bowl 1 is detachably placed on the support frame 4. The lower surface of the sieve plate 26 is provided with a sealing ring 39 and multiple springs 27. The purging assembly includes a purger 28, a transmission ventilator 38, and a motor 23. The purger 28 is connected to the motor 23 through the transmission ventilator 38. The motor 23 is fixed on the purging bracket 25. The purging bracket 25 is installed on the upper surface of the sieve plate 26, and the rotation axis of the purger 28 is aligned with the center hole of the sieve plate 26.

[0030] Furthermore, such as Figures 1-7As shown, the sieve plate 26 has four holes, namely an air inlet, a fine powder discharge hole, a coarse powder discharge hole, and a feed hole. Figure 6 In the middle, a screen assembly 37 is installed at the fine powder discharge hole by screws, allowing only powder particles not exceeding a certain size to pass through; the air inlet is equipped with a blower 28 in the center; for the remaining two holes without any components, the left one is the coarse powder discharge hole and the right one is the feed hole. Four springs 27 for providing thrust are also installed at the bottom of the screening plate 26.

[0031] For the three holes other than the air inlet, screen plate connector 1 32, screen plate connector 2 47, and screen plate connector 3 49 are installed at corresponding positions on the screen plate 26, along with solenoid valves 1 31, 2 46, and 3 48 (the opening and closing of the channels are controllable). At the air inlet position, a purge bracket 25 is installed on the screen plate 26. To ensure airtightness, sealing gaskets 40 are installed between screen plate connector 1 32, screen plate connector 2 47, screen plate connector 3 49, purge bracket 25, and screen plate 26 using screws.

[0032] according to Figure 2 and 3 The powder bowl 1 is placed on the support frame 4 and can be separated vertically. An electric cylinder 5, mounted on the bottom support surface 6, drives the support frame 4 to move up and down vertically. When moving upwards, the powder bowl 1 presses tightly against the sealing ring 39 mounted on the bottom surface of the sieve plate 26, forming a sealed space; at this time, all four springs 27 are compressed. When moving downwards, the support frame 4 can detach from the powder bowl 1, allowing the circular slot at the bottom of the powder bowl 1 to fall onto the support platform 2 placed on the electronic scale 3. A rubber pad 33 is placed under the electronic scale 3 to reduce the interference of vibration from the middle support surface 7 on the precision instrument measurement. The middle support surface 7, the bottom support surface 6, and the sieve plate 26 are rigidly connected by four frame supports 8.

[0033] For the fine powder discharge port and the coarse powder discharge port, a right-angle pipe connector 34 is installed on the upper side of the electromagnetic switch valve, and the other end is connected to the fine powder discharge pipe 21 and the coarse powder discharge pipe 22 respectively. The two are connected to the discharge pipe 17 through the T-shaped pipe connector 20 and lead to the cyclone collector 16. The upper part of the cyclone collector 16 is the airflow outlet pipe, which is driven by the negative pressure provided by the blower 14. The lower part of the cyclone collector 16 is connected to the waste collection bottle 10 through threads. The powder particles in the airflow are separated from the airflow in the cyclone collector 16 and fall into the bottle, realizing the recovery of powder. The feed hole on the screen plate 26 is equipped with a feed funnel 24 for receiving materials.

[0034] The blower 28 has small holes on its two hemispherical surfaces and elongated slots on the top and bottom of one side. A thin brush 29 is mounted on the top of the other side. The drive ventilator 38 has a solid shaft at its center with threads to transmit torque and rotational motion from the motor 23 (fixed to the blower bracket 25). A hollow tube is rigidly connected to the outside of the solid shaft by three thin plates, and the hollow tube has threads on its lower side that connect to the blower 28. The torque and motion of the solid shaft are transmitted to the blower 28 through the thin plates and the hollow tube. Further, the torque and motion of the motor 23 are transmitted to the lower half 35 of the LM coupling through the upper half 36. Since the lower half 35 of the LM coupling has a square hole of the same size as the torque transmitter 43, and the torque transmitter 43 and the drive ventilator 38 are connected by threads, the torque and motion can be transmitted from the lower half 35 of the LM coupling to the drive ventilator 38. Nut 44 is used to prevent the lower half 35 of the LM coupling and the torque transmitter 43 from falling off and separating. In order to reduce the friction of the movement and improve the stability of the movement, a flat bearing 45 for the fixed-axis rotation of the lower half 35 of the LM coupling, and rolling bearings 42 and 41 for the fixed-axis rotation of the drive ventilator 38 are installed in the purge bracket 25.

[0035] The blower 11 blows clean, dry external gas into the gas heating tube 18 through the first air inlet pipe 12 and the second air inlet pipe 9, heating it into high-temperature gas. Then, it blows the gas into the purging bracket 25 through the third air inlet pipe 19. The high-temperature gas is blown into the sealed space formed by the bottom surface of the sieve plate 26 and the powder bowl 1 through the hollow tube of the purging bracket 25, the drive ventilator 38, and the holes in the inner cavity of the blower 28. When the motor 23 rotates, the blower 28 sprays out high-pressure, high-temperature gas while simultaneously rotating at a constant speed around its central axis, thus generating sufficient turbulence to agitate the powder in the powder bowl 1. (At this time, the electromagnetic switch valve 31 at the feed port should be closed, and at least one of the electromagnetic switch valves 46 or 48 should be open).

[0036] The center of the screen assembly 37 (i.e., the center of the fine powder discharge hole) is relatively close to the rotation axis of the blower 28. This distance corresponds to the position of the thin brush 29 and the elongated slot on the other side of the blower 28, ensuring that the blower 28 can effectively perform physical brushing and air cleaning of the screen during rotation, preventing filter clogging. The centers of the other two holes on the screening plate 26 (the coarse powder discharge hole and the feed hole) are relatively far from the rotation axis of the blower 28, and the distances are equal. This avoids the thin brush 29 and the air jet from the elongated slot on the blower 28 affecting them.

[0037] The sensing end of thermocouple 30 extends to the lower surface of sieve plate 26 to detect the temperature there. A programmable logic controller (not shown) is used to control the orderly operation of the system.

[0038] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0039] Working principle:

[0040] Weighing the empty bowl. The electric cylinder 5 retracts, causing the powder bowl 1 to detach from the support frame 4 and fall onto the electronic scale 3, with the circular groove on the lower surface of the powder bowl 1 in close contact with the bowl support platform 2. The mass of the empty powder bowl 1 is read as M0. Then, the electric cylinder 5 extends, causing the support frame 4 to lift the powder bowl 1 until the powder bowl 1 is tightly pressed against the sealing ring 39 at the bottom of the sieve plate 26.

[0041] Preheat the cavity. Power on the gas heating tube 18, and turn on the electromagnetic switch valve 46, electromagnetic switch valve 48, blower 14, blower 11, and motor 23 (running at low speed) to heat the powder bowl 1 and the main components of the gas circuit with hot air. When the temperature of the powder bowl 1 reaches 105 degrees Celsius, turn off the above devices in sequence.

[0042] Weigh the entire sample. Open the solenoid valve 31 and pour a certain amount of powder into the powder bowl 1 through the feed funnel 24. Close the solenoid valve 31. The electric cylinder 5 retracts, causing the powder bowl 1 to detach from the support frame 4 and fall onto the electronic scale 3, with the circular groove on the lower surface of the powder bowl 1 in close contact with the support platform 2. Read the mass of the empty powder bowl 1 as M1. Then, the electric cylinder 5 extends, causing the support frame 4 to lift the powder bowl 1 until the powder bowl 1 is tightly pressed against the sealing ring 39 at the bottom of the sieve plate 26.

[0043] Screening of small powder particles. Powering on the gas heating element 18, and opening the solenoid valve 46, blower 14, blower 11, and motor 23 (running at high speed), the powder particles smaller than the pore size are drawn through the screening assembly 37. Continue for 60 seconds.

[0044] Shake off any remaining sample. Turn off the above-mentioned devices, keeping only motor 23 running. Alternately rotate the motor three times in a forward, reverse, and stop manner, each rotation lasting 15 seconds (high-speed operation) to thoroughly shake off the large-diameter powder particles that fell onto the blower 28 and thin brush 29 during the previous screening step. After completion, turn off the motor and let the entire machine stand for 60 seconds to allow the powder in the bowl to settle.

[0045] The remaining sample is weighed. The electric cylinder 5 retracts, causing the powder bowl 1 to detach from the support frame 4 and fall onto the electronic scale 3, with the circular groove on the lower surface of the powder bowl 1 in close contact with the support platform 2. The mass of the empty powder bowl 1 is read as M2. Then, the electric cylinder 5 extends, causing the support frame 4 to lift the powder bowl 1 until the powder bowl 1 is tightly pressed against the sealing ring 39 at the bottom of the sieve plate 26.

[0046] Fineness calculation. Fineness = (1 - (M1 - M2) / (M1 - M0)) × 100%.

[0047] Clean up any remaining sample. Power on the gas heating tube 18, and turn on the electromagnetic switch valve 3 48, blower 2 14, blower 1 11, and motor 23 (running at high speed). Suction the remaining large-particle powder sample from the powder bowl 1 through the coarse powder discharge pipe 21. After 90 seconds, turn off the above devices.

[0048] Waste collection bottle cleaning. After completing 30 tests, manually replace 10 empty waste collection bottles.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0050] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A powder fineness measuring device, comprising a powder bowl (1), a supporting frame (4), an electric cylinder (5), a screening plate (26), a blowing assembly and a frame support (8), characterized in that: the frame support (8) rigidly connects the bottom support surface (6), the middle support surface (7) and the screening plate (26) to form an integral support structure; the supporting frame (4) is located above the bottom support surface (6) and is connected with the output end of the electric cylinder (5), the electric cylinder (5) is fixed on the bottom support surface (6) and is used to drive the supporting frame (4) to move in the vertical direction; the powder bowl (1) is detachably placed on the supporting frame (4), and the lower surface of the screening plate (26) is provided with a sealing ring (39) and a plurality of springs (27); the blowing assembly comprises a blower (28), a transmission ventilator (38) and a motor (23), the blower (28) is connected with the motor (23) through the transmission ventilator (38), the motor (23) is fixed on a blowing support (25), the blowing support (25) is installed on the upper surface of the screening plate (26), and the rotation axis of the blower (28) is aligned with the center hole of the screening plate (26). The screening plate (26) is provided with a fine powder discharge hole, a coarse powder discharge hole, a feeding hole and an air inlet hole, the fine powder discharge hole is provided with a detachable screen assembly (37), the air inlet hole is fixed with the blower (28), and the feeding hole is provided with a feeding hopper (24) above; the fine powder discharge hole and the coarse powder discharge hole are connected with a fine powder discharge pipe (21) and a coarse powder discharge pipe (22) through right-angle pipe connecting pieces (34) respectively, the two pipes are merged into a discharge pipe one (17) through a T-shaped pipe connecting piece (20) and are extended to a cyclone collector (16); the feeding hole is provided with an electromagnetic switch valve one (31), the coarse powder discharge hole is provided with an electromagnetic switch valve two (46), and the fine powder discharge hole is provided with an electromagnetic switch valve three (48) for controlling the opening and closing of each hole. Small holes are opened on the hemispherical surfaces of the two ends of the blower (28), one side is provided with a thin surface brush (29), and the other side is provided with a long strip-shaped hole groove, the distance between the thin surface brush (29) and the screen assembly (37) is 3-5 cm; The transmission ventilator (38) comprises a solid shaft and a hollow pipe, the solid shaft is connected with the blower (28) through threads, the hollow pipe is rigidly connected with the solid shaft through a thin plate, and the outer side of the hollow pipe is provided with a rolling bearing one (41) and a rolling bearing two (42); The blowing support (25) is provided with a plane bearing (45) for supporting a LM coupling lower half (35), the LM coupling lower half (35) is threadedly connected with the solid shaft of the transmission ventilator (38) through a torque transmitter (43) and is fixed through a locking nut (44).

2. The powder fineness measuring device according to claim 1, characterized in that: The thickness of the sealing ring (39) is 0.5-1 cm, and the sealing ring (39) is fixed with the lower surface of the screening plate (26) through screws; The springs (27) are symmetrically distributed at the four corners of the lower surface of the screening plate (26), and the compression stroke of each spring (27) is 2-4 cm; The lower surface of the screening plate (26) is also provided with a sealing gasket (40) for enhancing the sealing between the screening plate (26) and the blowing support (25).

3. The powder fineness measuring device according to claim 2, characterized in that: ​ ​ ​ 4. The powder fineness measuring device according to claim 1, characterized in that: ​ ​ ​ 5. The powder fineness measuring device according to claim 1, characterized in that: The electronic scale (3) is fixed on the middle supporting surface (7) and is isolated from the bowl supporting table (2) by rubber pads (33); The bowl supporting table (2) is provided with a circular groove matching the bottom clamping slot of the powder bowl (1), and the groove depth is 1-2 cm; The detection end of the thermocouple (30) extends into the lower surface of the screening plate (26) for detecting the temperature in the sealed chamber.

6. The powder fineness measuring device according to claim 1, characterized in that: The gas heating pipe (18) is communicated with the blowing support (25) through the gas inlet pipe one (12), the gas inlet pipe two (9) and the gas inlet pipe three (19), and the pipe diameter of the gas inlet pipe three (19) is 2-3 cm; The air blower one (11) and the air blower two (14) are respectively controlled by the electromagnetic switch valve one (31), the electromagnetic switch valve two (46) and the electromagnetic switch valve three (48) to control the on-off of the gas; The discharge pipe two (15) and the discharge pipe three (13) are respectively connected with the cyclone collector (16) and the air blower two (14) for discharging the powder in the gas flow.

7. The powder fineness measuring device according to claim 1, characterized in that: The waste collecting bottle (10) is connected below the cyclone collector (16) by screwing, and the volume of the waste collecting bottle (10) is 500-1000 ml; The gas inlet of the cyclone collector (16) is connected with the discharge pipe one (17), and the gas outlet is communicated with the air blower two (14) through the discharge pipe two (15); The screening plate connecting piece one (32), the screening plate connecting piece two (47) and the screening plate connecting piece three (49) are respectively installed on the screening plate (26) for connecting the fine powder discharge hole, the coarse powder discharge hole and the feeding hole.

8. The powder fineness measuring device according to claim 1, characterized in that: The upper half of the LM coupling (36) is connected with the output shaft of the motor (23), and the lower half of the LM coupling (35) is connected with the torque transmitter (43) for transmitting the torque of the motor (23); The screening plate (26) is also provided with rubber pads (33) for reducing the interference of vibration on the electronic scale (3).

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