Multi-stage conveying device for powder conveying

Abstract

The utility model relates to be used for powder transmission multistage transmission device, including the storage tank for storing powder, with the storage tank connection first grade screw conveyer, its contained spiral blade one adopts variable diameter structure, from the feed end to the discharge end blade diameter gradually reduces, and the first grade screw conveyer with horizontal plane inclination angle theta <=15 DEG, the drive motor of first grade screw conveyer one passes through frequency changer control rotating speed, with the second grade metering conveyer of first grade screw conveyer connection, the second grade metering conveyer's body has at least installed three weighing sensors, controller, weighing sensor and controller electric connection, the controller passes through communication module with frequency changer two -way communication, through the utility model can constant blade and the clearance between casing avoid material stagnation, ensure the continuity of conveying, automatic regulation first grade conveyer rotating speed, make material flow fluctuation be smaller, satisfy high -precision metering demand.

Description

Technical Field

[0001] This utility model relates to the field of powder conveying equipment technology, and in particular to a multi-stage conveying device for powder conveying. Background Technology

[0002] In industrial production, powder transport is a crucial link in many fields (such as building materials, chemicals, food, and battery manufacturing), and its transport efficiency and metering accuracy directly affect product quality and production benefits. However, traditional powder transport technologies have revealed many problems that urgently need to be solved in practical applications.

[0003] Current powder conveying technologies often rely on single-stage screw conveyors, whose screw blades are mostly of uniform diameter and installed at angles generally ≥30°. In this structure, during material conveying, the combined effect of gravity and blade friction easily creates an "arching effect" within the conveying channel, especially at the discharge end, where material accumulation and blockage are frequent. This not only severely impacts production continuity, but the frequent shutdowns for cleaning and equipment maintenance also significantly increase operating costs. The root cause is that the single-stage conveying structure cannot effectively balance the material's gravity and conveying power; the large angle exacerbates material accumulation due to its own weight; and the uniform diameter channel lacks an effective compression and guidance mechanism for the material, making it difficult to adapt to the complex flow characteristics of powders. Utility Model Content

[0004] This utility model addresses the shortcomings of existing technologies by providing a multi-stage conveying device for powder transport. The specific technical solution is as follows:

[0005] A multi-stage conveying device for powder material transfer includes a storage tank for storing powder; a primary screw conveyor connected to the storage tank, wherein the screw blades have a variable diameter structure, with the blade diameter gradually decreasing from the inlet end to the outlet end, and the inclination angle θ of the primary screw conveyor to the horizontal plane is ≤15°, and the drive motor of the primary screw conveyor has its speed controlled by a frequency converter; a secondary metering conveyor connected to the primary screw conveyor, wherein the body of the secondary metering conveyor is equipped with at least three weighing sensors; and a controller, wherein the weighing sensors are electrically connected to the controller, and the controller communicates bidirectionally with the frequency converter through a communication module.

[0006] Preferably, the inner diameter of the housing of the first-stage screw conveyor gradually decreases from the inlet end to the outlet end, which is compatible with the variable diameter structure of the first screw blade.

[0007] Preferably, the three weighing sensors are arranged in an isosceles triangle, with two weighing sensors symmetrically arranged on both sides of the spiral shell at the feed end of the secondary metering conveyor, and the other weighing sensor arranged on the center line at the discharge end of the secondary metering conveyor.

[0008] Preferably, a nut block is installed on the top of the weighing sensor, a threaded rod is connected to the nut block, a ball joint is installed on the top of the threaded rod, and the bottom of the primary screw conveyor has a groove, which is connected to the ball joint.

[0009] Preferably, it also includes a belt scale installed in the downstream section of the discharge end of the secondary metering conveyor, the belt scale feeding back the material flow signal to the controller in real time.

[0010] Preferably, the first-stage screw conveyor is axially rotatably connected to a rotating shaft, the output shaft of the first drive motor is connected to one end of the rotating shaft, and the first screw blade is connected to the surface of the rotating shaft.

[0011] Preferably, the secondary metering conveyor is internally connected to a rotating shaft two that rotates axially, and a drive motor two is installed on the outside of the secondary metering conveyor, with the output shaft of the drive motor two connected to one end of the rotating shaft two.

[0012] Preferably, a dust collection device and a safety valve are installed on the top of the storage tank, the bottom of the storage tank is connected to the interior of the primary screw conveyor body through a feed pipe, a first discharge pipe is connected between the primary screw conveyor body and the secondary metering conveyor, and a second discharge pipe is connected to the discharge end of the secondary metering conveyor.

[0013] Preferably, the spiral length L of the secondary metering conveyor is ≤2.5 meters.

[0014] The beneficial effects of this utility model are:

[0015] 1. The single-stage screw conveyor features a variable diameter structure (the blades and the inner diameter of the shell decrease synchronously) combined with a small inclination angle of ≤15°, reducing the impact of the material's gravitational force. The "arch bridge effect" is broken through the blade compression action, significantly reducing material blockage at the discharge end. The constant gap between the blades and the shell prevents material stagnation and ensures continuous conveying.

[0016] 2. Three weighing sensors are arranged in an isosceles triangle to monitor the weight of materials in the secondary metering conveyor in real time. Combined with a screw length of ≤2.5 meters, this reduces material accumulation errors. The controller, in conjunction with the belt scale flow feedback, automatically adjusts the speed of the primary conveyor to minimize material flow fluctuations and meet high-precision metering requirements. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the structure between the primary screw conveyor and the secondary metering conveyor in this utility model;

[0019] Figure 3 for Figure 2 A magnified structural diagram of point A in the middle.

[0020] Reference numerals: 1. Mounting bracket; 2. Storage tank; 21. Feed pipe; 22. Pneumatic butterfly valve; 3. Primary screw conveyor; 31. Drive motor one; 32. Rotating shaft one; 33. Spiral blade one; 34. First discharge pipe; 4. Secondary metering conveyor; 41. Drive motor two; 42. Rotating shaft two; 43. Spiral blade two; 44. Discharge pipe two; 45. Groove; 5. Spoke-type load cell; 51. Nut block; 52. Threaded rod; 53. Ball joint. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0022] Example

[0023] Please refer to Figures 1-3 A multi-stage conveying device for powder material transfer includes a storage tank 2 for storing powder material, a dust collection device (including a dust collection hood and a dust collector) and a safety valve installed on the top, and a feed pipe 21 at the bottom connected to a primary screw conveyor 3. A pneumatic butterfly valve 22 is installed on the feed pipe 21 to control the feeding.

[0024] The primary screw conveyor 3 is connected to the storage tank 2 and is used for the initial conveying of powder. The screw blade 33 adopts a variable diameter structure, with the blade diameter gradually decreasing from the feed end to the discharge end. This is combined with the design of synchronously decreasing inner diameter of the shell to maintain a constant gap between the blade and the inner wall of the shell and avoid material accumulation.

[0025] Its installation tilt angle θ ≤ 15° relative to the horizontal plane significantly reduces the impact of the material's gravitational force, thus minimizing the risk of accumulation. The drive motor 31 controls its speed via a frequency converter, enabling dynamic adjustment of the conveying capacity.

[0026] The secondary metering conveyor 4 is connected to the primary screw conveyor 3 via the first discharge pipe 34, and is used for precise metering of powder. The specific structure is as follows:

[0027] The weighing sensor has at least three spoke-type weighing sensors 5 installed on its body, which are distributed in an isosceles triangle (two are symmetrically arranged on both sides of the spiral shell at the feed end, and one is arranged on the center line at the discharge end) to monitor the weight of the material in real time.

[0028] The internal rotating shaft 42 of the spiral structure is connected to the drive motor 41, and the length L of the spiral blade 43 is ≤2.5 meters to ensure measurement accuracy.

[0029] The controller is electrically connected to the weighing sensor and communicates bidirectionally with the frequency converter through the communication module. It receives weight signals and adjusts the speed of the first-stage screw conveyor 3 based on the PID algorithm. At the same time, it can receive the flow signals fed back by the belt scale of the subsequent section to realize closed-loop control.

[0030] The discharge end of the secondary metering conveyor 4 is connected to the second discharge pipe, and the bottom is connected to the ball joint through the nut block 51 and the threaded rod 52. The ball joint is embedded in the groove 45 at the bottom of the primary screw conveyor 3 to achieve flexible support and weighing sensing.

[0031] The bottom feed pipe 21 of the storage tank 2 is connected to the inlet of the first-stage screw conveyor 3 via a flange. The pneumatic butterfly valve 22 is installed in the middle section of the feed pipe 21 to control the flow of materials.

[0032] The first discharge pipe 34 of the primary screw conveyor 3 is connected to the inlet flange of the secondary metering conveyor 4 to ensure smooth material transfer.

[0033] Nut block 51 is fixed to the bottom of the secondary metering conveyor 4. Threaded rod 52 passes through nut block 51. The top ball joint is embedded in the bottom groove 45 of the primary screw conveyor 3, forming a detachable flexible connection that supports the secondary conveyor and transmits weight signals. The load cell signal line is connected to the controller, which is connected to the frequency converter via a communication line. The belt scale signal line is also connected to the controller, forming a closed loop of "weighing-control-adjustment".

[0034] Specifically, the storage tank 2 is a cylindrical tank. The top dust collection device collects the dust generated during the powder conveying process through the dust collection hood and discharges it through the dust collector. The safety valve prevents the pressure inside the tank from being too high. The bottom feed pipe 21 is connected to the inlet flange of the first-stage screw conveyor 3. The pneumatic butterfly valve 22 is installed in the middle section of the feed pipe and is remotely controlled by the controller.

[0035] Specifically, the primary screw conveyor body is a cylindrical shell. An internal rotating shaft 32 is fixed to both ends of the shell via bearings. Spiral blades 33 are welded to the surface of the rotating shaft. From the feed end to the discharge end, the blade diameter gradually decreases from D1 to D2 (D1-D2 = 5-10mm), and the inner diameter of the shell simultaneously decreases from D1' to D2', maintaining a constant gap δ = 2-3mm between the blades and the inner wall of the shell. The drive motor 31 is connected to the rotating shaft via a coupling. A frequency converter controls the motor speed (adjustment range 0-50Hz). The bottom of the shell is fixed by a mounting bracket 1, with an installation tilt angle θ = 10° (the optimal angle measured in practice).

[0036] The secondary metering conveyor body is a cylindrical shell with a length L = 2.2 meters. The internal rotating shaft 42 is connected to the drive motor 41. The spiral blades 43 are designed with equal diameter, and the diameter matches the discharge end of the primary conveyor.

[0037] Three spoke-type load cells 5 are installed at the bottom: two are symmetrically distributed on both sides of the feed end (0.3L from the inlet end), and one is located on the center line of the discharge end (0.2L from the outlet end); the top nut block 51 of each sensor is fixed to the conveyor housing by bolts, the threaded rod 52 passes through the nut block, and the top ball joint 53 is embedded in the groove 45 at the bottom of the first-stage conveyor to form a flexible support.

[0038] The controller (PLC or microcontroller) receives the weight signal (sampling frequency 100Hz) from the weighing sensor 5, calculates the material flow rate per unit time, and compares it with the actual flow rate fed back by the belt scale (installed in the downstream section of the second discharge pipe 44). It outputs a 0-10V signal to the frequency converter through the PID algorithm to adjust the speed of the drive motor 31 so that the flow fluctuation is controlled within ±2%.

[0039] Working principle:

[0040] Material conveying process: Powder enters the primary screw conveyor 3 from the storage tank 2 through the feed pipe 21 and the pneumatic butterfly valve 22. The variable diameter screw blades 33 push the material towards the first discharge pipe 34 at an inclination angle of ≤15°. During the conveying process, the gradually narrowing structure of the blades and the shell squeezes the material and destroys the arch bridge effect.

[0041] The material enters the secondary metering conveyor 4 through the first discharge pipe 34. The equal diameter spiral blades 43 convey the material at a constant speed to the second discharge pipe 44. At the same time, three weighing sensors 5 monitor the weight change of the material in the conveyor in real time and calculate the instantaneous flow rate.

[0042] The controller adjusts the speed of the primary screw conveyor in real time based on the data from the weighing sensor and the actual flow rate feedback from the belt scale: if the actual flow rate is lower than the target value, the motor speed is increased; otherwise, the speed is reduced, thus achieving accurate measurement through closed-loop control.

[0043] The flexible support structure (ball joint 53 and groove 45) ensures that the load cell is not affected by additional shear force, thus improving measurement accuracy.

[0044] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A multi-stage conveying device for powder conveying, characterized in that, include: Storage tanks are used to store powders; The primary screw conveyor connected to the storage tank includes a screw blade with a variable diameter structure, where the blade diameter gradually decreases from the feed end to the discharge end, and the inclination angle θ of the primary screw conveyor to the horizontal plane is ≤15°. The drive motor of the primary screw conveyor has its speed controlled by a frequency converter. A secondary metering conveyor connected to a primary screw conveyor, wherein the body of the secondary metering conveyor is equipped with at least three weighing sensors; The controller is electrically connected to the weighing sensor, and the controller communicates bidirectionally with the frequency converter through a communication module.

2. The multi-stage conveying device for powder conveying according to claim 1, characterized in that: The inner diameter of the housing of the first-stage screw conveyor gradually decreases from the inlet end to the outlet end, which is compatible with the variable diameter structure of the first screw blade.

3. The multi-stage conveying device for powder conveying according to claim 2, characterized in that: The three weighing sensors are arranged in an isosceles triangle, with two weighing sensors symmetrically arranged on both sides of the spiral shell at the feed end of the secondary metering conveyor, and the other weighing sensor arranged on the center line at the discharge end of the secondary metering conveyor.

4. The multi-stage conveying device for powder conveying according to claim 3, characterized in that: A nut block is mounted on the top of the weighing sensor, a threaded rod is connected to the nut block, a ball joint is mounted on the top of the threaded rod, and the bottom of the primary screw conveyor has a groove that mates with the ball joint.

5. The multi-stage conveying device for powder conveying according to claim 1, characterized in that: It also includes a belt scale installed at the downstream section of the discharge end of the secondary metering conveyor, which feeds back the material flow signal to the controller in real time.

6. The multi-stage conveying device for powder conveying according to claim 1, characterized in that: The first-stage screw conveyor is internally connected to a rotating shaft one that rotates axially. The output shaft of the first drive motor is connected to one end of the rotating shaft two. The first screw blade is connected to the surface of the rotating shaft one.

7. The multi-stage conveying device for powder conveying according to claim 1, characterized in that: The secondary metering conveyor is internally connected to a rotating shaft two that rotates axially. A drive motor two is installed on the outside of the secondary metering conveyor, and the output shaft of the drive motor two is connected to one end of the rotating shaft two.

8. The multi-stage conveying device for powder conveying according to claim 1, characterized in that: The top of the storage tank is equipped with a dust collection device and a safety valve. The bottom of the storage tank is connected to the interior of the primary screw conveyor body through a feed pipe. The primary screw conveyor body and the secondary metering conveyor are connected by a first discharge pipe. The discharge end of the secondary metering conveyor is connected to a second discharge pipe.

9. The multi-stage conveying device for powder conveying according to claim 1, characterized in that: The spiral length L of the secondary metering conveyor is ≤2.5 meters.

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