Energy-saving closed-circuit powder recycling structure of mine powder processing equipment

Abstract

The utility model provides a kind of energy -conserving back powder closed circuit circulation structure of mine powder processing equipment belongs to closed circuit circulation structure technical field, and the energy -conserving back powder closed circuit circulation structure of this mine powder processing equipment includes grading cylinder, back powder pipeline and conveying spiral, wherein, the barrel wall of grading cylinder is narrow in upper and wide in lower frustum, the bottom center position of grading cylinder is equipped with discharge port, the feeding end of back powder pipeline is connected with the upper portion of the lateral wall of grading cylinder, the discharge end of back powder pipeline is connected with the lower portion of the lateral wall of grading cylinder, conveying spiral is arranged in back powder pipeline interior, and clearance is formed between the helical blade of conveying spiral and the inner wall of back powder pipeline, the width of clearance gradually decreases along the length direction of back powder pipeline, and the problems that the existing mine powder processing equipment is caused by the low cycle efficiency and high energy consumption due to the unreasonable design of back powder circulation system are solved.

Description

Technical Field

[0001] This utility model belongs to the technical field of closed-loop circulation structure, specifically, it relates to an energy-saving closed-loop circulation structure for powder return in mining powder processing equipment. Background Technology

[0002] In the mining and processing industry, after ore undergoes crushing and grinding processes, it needs to be separated into powders according to particle size using grading equipment. Fine powder meeting the requirements is output as the final product, while coarse powder that does not meet the size requirements needs to be returned to the grinding equipment for further processing. Traditional mining powder processing production lines typically employ an open-circuit production model. After the coarse powder is discharged, it needs to be lifted and transported back to the grinding mill feed inlet using additional equipment such as bucket elevators or pneumatic conveyors. These auxiliary conveying devices not only increase the complexity and investment cost of the system but also consume a significant amount of electrical energy during operation. In particular, bucket elevators need to overcome the entire weight of the powder for vertical lifting, and pneumatic conveyors need to provide high-pressure airflow to carry the powder particles. The energy consumption of these two methods is considerable. Both are very considerable. Another common approach is to use a simple gravity powder return method. However, existing gravity powder return systems usually use straight cylindrical classifying cylinders and straight powder return pipes. This structural design causes powder to easily accumulate inside the cylinder and flow poorly in the pipe. It is necessary to equip the system with vibrators or airflow purging devices to assist powder flow, which increases energy consumption and equipment complexity. Existing conveying screws mostly adopt standard designs with equal gaps and thicknesses, which fail to optimize for the actual needs of different conveying stages, resulting in low conveying efficiency and uneven wear. With the continuous improvement of energy conservation and consumption reduction requirements of mining enterprises and the increasingly stringent environmental protection policies, the development of a simple, efficient and energy-saving closed-loop powder return system has become an urgent need for the development of mining powder processing equipment technology. Utility Model Content

[0003] In view of this, the present invention provides an energy-saving closed-loop circulation structure for the return powder of mining powder processing equipment, which solves the problems of low circulation efficiency and high energy consumption caused by unreasonable design of the return powder circulation system in existing mining powder processing equipment.

[0004] This utility model is implemented as follows:

[0005] This utility model provides an energy-saving closed-loop circulation structure for powder recovery in a mining powder processing equipment, including a classifying cylinder, a powder recovery pipe, and a conveying screw. The classifying cylinder has a frustoconical shape with a narrow top and a wide bottom. A discharge port is provided at the center of the bottom of the classifying cylinder. The inlet end of the powder recovery pipe is connected to the upper part of the side wall of the classifying cylinder, and the outlet end of the powder recovery pipe is connected to the lower part of the side wall of the classifying cylinder. The conveying screw is disposed inside the powder recovery pipe, and a gap is formed between the spiral blades of the conveying screw and the inner wall of the powder recovery pipe. The width of the gap gradually decreases along the length of the powder recovery pipe.

[0006] The technical advantages of the energy-saving closed-loop circulation structure for powder return in mining powder processing equipment provided by this utility model are as follows: By designing the classifying cylinder as a frustum-shaped structure that is narrow at the top and wide at the bottom, the powder naturally concentrates downwards under the action of gravity. Combined with the powder return pipe connecting the upper and lower parts of the classifying cylinder, a closed-loop circulation is formed. The conveying screw is set inside the powder return pipe to achieve continuous powder conveying. The design of the gradually decreasing gap between the screw blades and the inner wall of the pipe along the length direction causes the powder to be subjected to gradually enhanced compression during conveying, promoting close contact between powder particles, reducing energy loss during conveying, and realizing the energy-saving closed-loop circulation function for powder return, ensuring the continuity and high efficiency of the powder processing process.

[0007] Based on the above technical solution, the energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment of this utility model can be further improved as follows:

[0008] The inclination angle of the frustoconical wall of the grading cylinder is 15° to 30°.

[0009] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by limiting the inclination angle of the frustum-shaped cylinder wall of the classifying cylinder to the range of 15 degrees to 30 degrees, it ensures that the powder can slide smoothly down in the cylinder without accumulation and blockage, and avoids that the powder falling too fast due to the excessive inclination angle, which would prevent sufficient classification. This allows powder particles of different coarseness to be effectively separated under the combined action of gravity and airflow, improving classification efficiency while reducing the overall height of the equipment, reducing material consumption and floor space.

[0010] Furthermore, the connection position of the feed end of the return powder pipe on the side wall of the classifying cylinder is higher than the connection position of the discharge end of the return powder pipe on the side wall of the classifying cylinder, and the height difference between the two is 1 / 2 to 2 / 3 of the total height of the classifying cylinder.

[0011] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by setting the connection position of the feed end of the return powder pipeline higher than the connection position of the discharge end, and controlling the height difference between the two within the range of one-half to two-thirds of the total height of the classifier, the powder is conveyed downward in the return powder pipeline by the combined action of its own gravity and the driving force of the conveying screw, which reduces the power demand of the conveying screw and reduces the power consumption. At the same time, the reasonable height difference design ensures that the powder maintains an appropriate flow speed in the pipeline, avoiding blockage caused by too slow speed or pipeline wear caused by too fast speed.

[0012] Furthermore, the outer edge of the spiral blades of the conveying spiral is wavy, and the distance between the crest of the wave and the inner wall of the powder return pipe is less than the distance between the trough of the wave and the inner wall of the powder return pipe.

[0013] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by designing the outer edge of the spiral blade of the conveying screw to be wavy, the spiral blade generates a periodic squeezing and releasing effect on the powder during rotation. The peak position applies a strong pushing force to the powder, and the trough position provides the powder with a short buffer space. This periodic action breaks the static friction state between powder particles, making the powder flow more smoothly in the pipeline, reducing the conveying resistance, reducing the torque required for the spiral rotation, thereby reducing the power consumption of the drive motor and extending the service life of the equipment.

[0014] Furthermore, the thickness of the spiral blades of the conveying spiral gradually increases along the spiral axial direction, with the thickness of the spiral blades near the feed end being less than that near the discharge end.

[0015] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by gradually increasing the thickness of the spiral blades of the conveying screw along the axial direction of the screw, the spiral blades near the discharge end have stronger structural strength and wear resistance, and can withstand greater thrust and more severe wear, while the thinner blades near the feed end reduce the overall weight and reduce the inertial load during startup and operation. This gradual thickness design is optimized according to the actual working intensity of different positions, and achieves lightweight design while ensuring the strength of key parts, thereby reducing material costs and operating energy consumption.

[0016] Furthermore, the powder return pipe has an arc-shaped curved structure, and the bending radius of the powder return pipe is 8 to 12 times the diameter of the powder return pipe.

[0017] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by designing the return powder pipeline as an arc-shaped curved structure and controlling the bending radius within the range of 8 to 12 times the pipe diameter, the problems of powder flow obstruction and local accumulation caused by right-angle bends or excessively small bending radii are avoided. This allows the powder to flow along a smooth curved path in the pipeline, reducing abrupt changes in direction and velocity loss during the flow process, and lowering the wear rate of the inner wall of the pipeline. At the same time, the arc-shaped structure gives the pipeline a certain elastic buffering capacity, which can absorb the vibration generated when the conveying screw is running, thus improving the stability and reliability of the system operation.

[0018] Furthermore, the edge of the discharge port of the grading cylinder extends inward to form an annular boss. The inner diameter of the annular boss is smaller than the outer diameter of the discharge port, and the height of the annular boss is 1 / 3 to 1 / 2 of the thickness of the bottom of the grading cylinder.

[0019] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By extending an annular boss inward from the edge of the discharge port of the classifier cylinder, and designing the inner diameter of the annular boss to be smaller than the outer diameter of the discharge port, and controlling the height of the annular boss within the range of one-third to one-half of the bottom thickness, the powder must pass through the contraction channel formed by the annular boss when it is discharged from the discharge port. This contraction channel has a rectifying effect on the powder flow, making the powder flow discharged in a more concentrated and stable state, reducing the phenomenon of powder flying and scattering. At the same time, the annular boss also plays a role in supporting and strengthening the structure of the discharge port, preventing the edge of the discharge port from deforming and being damaged during long-term use.

[0020] Furthermore, the diameter of the central shaft of the conveying screw increases in a stepped manner along the axial direction, with the diameter difference between two adjacent stepped segments being 2mm to 5mm.

[0021] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By designing the diameter of the central shaft of the conveying screw to increase in a stepped manner along the axial direction, with the diameter difference between adjacent stepped sections controlled within the range of 2 mm to 5 mm, the stress distribution at the connection between the screw blade and the shaft is made more uniform, avoiding the stress concentration problem caused by shafts of equal diameter in different load sections. The stepped increasing design allows the part near the discharge end that bears greater torque to have a larger shaft diameter and stronger torsional resistance, while the feed end uses a smaller diameter to reduce weight. This design has been specifically optimized according to the actual stress conditions, improving the overall reliability of the shaft and reducing material consumption.

[0022] Furthermore, the powder return pipe is made of stainless steel, the conveying screw is made of wear-resistant alloy steel, and the grading cylinder is made of carbon steel.

[0023] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By selecting stainless steel for the powder return pipe, wear-resistant alloy steel for the conveying screw, and carbon steel for the classifying cylinder, the materials were rationally matched according to the different working environments and performance requirements faced by each component during operation. Stainless steel gives the powder return pipe good corrosion resistance and surface smoothness, wear-resistant alloy steel gives the conveying screw excellent wear resistance and service life, and carbon steel reduces the manufacturing cost of the classifying cylinder while ensuring sufficient strength. This material combination scheme achieves the best balance between cost and performance while meeting the functional requirements of each component.

[0024] Furthermore, the inner surface of the frustoconical wall of the grading cylinder is provided with multiple axially extending guide grooves, the depth of the guide grooves is 2mm to 4mm, and the spacing between two adjacent guide grooves is 1 / 12 to 1 / 8 of the circumference of the inner wall of the grading cylinder.

[0025] The beneficial effects of the above-mentioned improvement scheme are as follows: By setting axially extending guide grooves on the inner surface of the frustoconical cylinder wall of the classifying cylinder, with the groove depth controlled between 2 mm and 4 mm and the spacing between adjacent guide grooves being one-twelfth to one-eighth of the inner wall circumference, the powder is guided by the guide grooves when sliding down the inner surface of the cylinder wall, which changes the movement trajectory of the powder particles, increases the residence time of the powder in the cylinder and the length of the movement path, and gives powder particles of different sizes a more sufficient opportunity to be separated under the action of airflow. The presence of the guide grooves also disrupts the smoothness of the cylinder wall surface, prevents the powder from forming an adhesion layer on the cylinder wall, maintains the cleanliness of the cylinder wall, and improves the stability and continuity of the classification effect.

[0026] Compared with existing technologies, the beneficial effects of the energy-saving closed-loop circulation structure for powder return in mining powder processing equipment provided by this utility model are as follows: This utility model designs the classifying cylinder as a frustum-shaped structure that is narrow at the top and wide at the bottom, making full use of the powder's own gravity to achieve natural falling and initial classification. Combined with the vertically connected return pipe, a complete closed-loop circulation path is formed, allowing substandard powder to continuously return to the processing flow without the need for additional lifting devices. The spiral blades of the conveying screw form a gradually decreasing gap along the length of the return pipe, causing the powder to be subjected to gradually increasing compression and pushing forces during conveying. This reduces the voids between powder particles, improves conveying density and efficiency, and reduces the required conveying capacity per unit mass of powder. The system boasts a compact and simple structure, comprising only three main components: a classifying cylinder, a powder return pipe, and a conveying screw. This reduces manufacturing costs and maintenance complexity. The combined design of the frustum-shaped classifying cylinder and the arc-shaped powder return pipe ensures a smooth powder flow path without dead angles, preventing powder accumulation and clogging. The innovative design of the wave-shaped spiral blades and stepped shaft further optimizes conveying performance and structural strength. The guide channel enhances the classification effect. The entire system achieves efficient powder return circulation while significantly reducing energy consumption, improving the overall performance and economic benefits of mining powder processing equipment. Compared to traditional open-circuit processing systems or powder return systems using additional lifting equipment, this invention offers significant energy savings and a simpler, more reliable structure. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 An example diagram of an energy-saving closed-loop circulation structure for powder return in a mining powder processing equipment;

[0029] Figure 2 A perspective view of an energy-saving closed-loop circulation structure for powder return in a mining powder processing equipment;

[0030] The attached diagram lists the components represented by each number as follows:

[0031] 10. Grading cylinder; 11. Discharge port; 20. Powder return pipe; 30. Conveying screw; 31. Screw blade. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0033] like Figure 1 , Figure 2 The diagram shown is an example of an energy-saving closed-loop circulation structure for a mining powder processing equipment provided by this utility model. It includes a classifying cylinder 10, a powder return pipe 20, and a conveying screw 30. The classifying cylinder 10 has a frustum-shaped wall that is narrower at the top and wider at the bottom. A discharge port 11 is located at the center of the bottom of the classifying cylinder 10. The inlet end of the powder return pipe 20 is connected to the upper part of the side wall of the classifying cylinder 10, and the outlet end of the powder return pipe 20 is connected to the lower part of the side wall of the classifying cylinder 10. The conveying screw 30 is located inside the powder return pipe 20, and a gap is formed between the screw blades 31 of the conveying screw 30 and the inner wall of the powder return pipe 20. The width of the gap gradually decreases along the length of the powder return pipe 20.

[0034] The specific operation or usage method involves first checking the connection status of all components of the classifying cylinder's return powder pipeline and conveying screw before starting the mining powder processing equipment. Ensure all bolts are tight and secure, and that there are no foreign objects blocking the pipeline. Then, start the drive motor of the conveying screw to rotate it at the set speed. Next, start the grinding equipment and the classifying airflow system. The ground powder enters the classifying cylinder with the airflow. Inside the frustum-shaped cylinder, fine powder is carried by the rising airflow and discharged from the top of the classifying cylinder into the collection system. Coarse powder settles to the bottom of the classifying cylinder under gravity and enters the return powder pipeline through the discharge port. The conveying screw pushes the coarse powder upwards along the return powder pipeline. The coarse powder re-enters the upper area of ​​the classifying cylinder from the feed inlet at the top of the return powder pipeline, mixes with the newly entered ground powder, and is classified again. This cycle repeats continuously, with the substandard coarse powder circulating in the system until it is ground to the qualified particle size and discharged with the airflow. During operation, the flow of powder in the classifying cylinder and the conveying status of the return powder pipeline should be observed regularly. If the powder flow is obstructed or the conveying screw is abnormally loaded, the machine should be stopped immediately for inspection and removal of any possible blockages. After long-term operation, the bearings of the conveying screw should be lubricated according to the maintenance plan, and the wear of the screw blades should be checked. Severely worn parts should be repaired or replaced. When stopping the machine, the feeding should be stopped first, and the conveying screw drive motor and the classifying airflow system should be turned off in sequence after the powder in the system has been basically emptied. The powder adhering to the inner wall of the classifying cylinder and the inner wall of the return powder pipeline should be cleaned regularly to keep the system clean and ensure long-term stable and efficient operation of the equipment.

[0035] In the above technical solution, the inclination angle of the frustum-shaped cylinder wall of the grading cylinder 10 is 15° to 30°.

[0036] Furthermore, in the above technical solution, the connection position of the feed end of the return powder pipe 20 on the side wall of the classifying cylinder 10 is higher than the connection position of the discharge end of the return powder pipe 20 on the side wall of the classifying cylinder 10, and the height difference between the two is 1 / 2 to 2 / 3 of the total height of the classifying cylinder 10.

[0037] Furthermore, in the above technical solution, the outer edge of the spiral blade 31 of the conveying spiral 30 is wavy, and the distance between the peak position and the inner wall of the return powder pipe 20 is smaller than the distance between the trough position and the inner wall of the return powder pipe 20.

[0038] Furthermore, in the above technical solution, the thickness of the spiral blade 31 of the conveying spiral 30 gradually increases along the spiral axial direction, and the thickness of the spiral blade 31 near the feed end is less than the thickness of the spiral blade 31 near the discharge end.

[0039] Furthermore, in the above technical solution, the powder return pipe 20 has an arc-shaped curved structure, and the bending radius of the powder return pipe is 8 to 12 times the diameter of the powder return pipe 20.

[0040] Furthermore, in the above technical solution, the edge of the discharge port 11 of the grading cylinder 10 extends inward to form an annular boss. The inner diameter of the annular boss is smaller than the outer diameter of the discharge port 11, and the height of the annular boss is 1 / 3 to 1 / 2 of the thickness of the bottom of the grading cylinder 10.

[0041] Furthermore, in the above technical solution, the diameter of the central shaft of the conveying screw 30 increases in a stepped manner along the axial direction, and the diameter difference between two adjacent stepped sections is 2mm to 5mm.

[0042] Furthermore, in the above technical solution, the powder return pipe 20 is made of stainless steel, the conveying screw 30 is made of wear-resistant alloy steel, and the classifying cylinder 10 is made of carbon steel.

[0043] Furthermore, in the above technical solution, the inner surface of the frustoconical cylinder wall of the grading cylinder 10 is provided with multiple axially extending guide grooves, the groove depth is 2mm to 4mm, and the distance between two adjacent guide grooves is 1 / 12 to 1 / 8 of the circumference of the inner wall of the grading cylinder 10.

[0044] Specific Embodiment 1: The grading cylinder is welded from carbon steel plates. The cylinder body is generally truncated cone-shaped, with an upper opening diameter of 800 mm and a lower opening diameter of 1200 mm. The total height of the cylinder is 2000 mm. The angle between the side wall of the truncated cone and the vertical direction is 20 degrees. A circular discharge port with a diameter of 200 mm is opened at the center of the bottom of the grading cylinder. The edge of the discharge port extends inward to form an annular boss with a height of 15 mm and an inner diameter of 180 mm. The annular boss is made by integral stamping with the bottom plate to ensure structural strength. A feed inlet is opened on the upper part of the side wall of the grading cylinder, 400 mm from the top. The feed inlet is a rectangular opening with a size of 150 mm x 200 mm. The lower part of the side wall... A discharge port is located 500 mm from the bottom of the grading cylinder. The discharge port is also rectangular, measuring 120 mm x 150 mm. Sixteen guide grooves are evenly distributed axially along the inner wall of the grading cylinder. These grooves are made of angle steel welded to the inner surface of the cylinder wall. Each guide groove is 3 mm deep and 20 mm wide, with a spacing of 235 mm between adjacent grooves. The return powder pipe is made of seamless stainless steel tubing with an inner diameter of 150 mm and a wall thickness of 5 mm. The pipe is curved with a bending radius of 1500 mm, and its total length is 3500 mm. Both ends of the return powder pipe are connected to the inlet and outlet on the side wall of the grading cylinder via flanges. Rubber gaskets are used at the flange connections to ensure airtightness. The central shaft of the conveying screw is made of wear-resistant alloy steel and consists of three stepped sections. The first section, near the feed end, is 1200 mm long and 40 mm in diameter; the middle section is 1200 mm long and 45 mm in diameter; and the third section, near the discharge end, is 1100 mm long and 50 mm in diameter. Adjacent stepped sections are transitioned by an arc with a radius of 10 mm. The spiral blades are cut and welded to the central shaft from wear-resistant alloy steel sheet. The outer diameter of the spiral blades is 145 mm at the feed end and 140 mm at the discharge end. The gap between the spiral blades and the inner wall of the pipe is 2.5 mm at the feed end and 5 mm at the discharge end, exhibiting a linear gradient. The thickness of the spiral blades is 8 mm at the feed end. The material is 12 mm at the discharge end, also exhibiting a linear gradient. The outer edge of the spiral blades is laser-cut into a wavy shape, with a height difference of 3 mm between the crest and trough, and a wave period of 200 mm. The pitch of the conveying spiral is 300 mm. The conveying spiral is installed at both ends of the return powder pipeline via bearing housings made of cast iron, with deep groove ball bearings (model 6210) installed inside. The conveying spiral is driven by a 3 kW three-phase asynchronous motor with a speed of 960 rpm, connected to the central shaft of the conveying spiral via a coupling. When the entire system is working, the air velocity of the grading airflow is 1.5 m / s to 2.0 m / s, and the conveying speed of the coarse powder in the return powder pipeline is 0.5 m / s to 0.At a speed of 8 meters per second, the system can process 2 to 3 tons of powder material per hour. The circulation return flow of coarse powder accounts for approximately 30% to 40% of the total processing capacity. Compared to traditional powder return systems using bucket elevators, the energy consumption of this embodiment is reduced by approximately 40%.

[0045] Specific Embodiment 2: This Embodiment 2 is based on Embodiment 1, and further optimizes the structure of the conveying screw. Multiple through holes are opened radially on the surface of the screw blades. The through holes are circular with a diameter of 8 mm. Twelve through holes are evenly distributed on each turn of the screw blades, and the distance between adjacent through holes is 78 mm. The through holes allow some fine particles to pass through the through holes and flow back and forth when the powder is pushed by the screw blades, reducing the accumulation of powder in the screw groove. At the same time, the presence of through holes reduces the effective pushing area of ​​the screw blades, making the conveying process more stable and reducing the risk of powder compaction and pipe blockage caused by excessive thrust. In addition, six evenly distributed small protrusions are added to the annular protrusion at the bottom of the discharge port of the classifying cylinder. Each small protrusion is hemispherical with a diameter of 10 mm and a height of 5 mm. The function of these small protrusions is to further disturb the powder flow and prevent coarse particles from forming bridging blockage near the discharge port, thereby improving the continuity and stability of the discharge. Through these detailed improvements, this embodiment further improves the operational reliability of the system, reduces the powder blockage failure rate by about 60%, and extends the maintenance cycle by about 50%.

[0046] Specifically, the principle of this invention is as follows: Utilizing the geometric characteristics of a frustum-shaped classifying cylinder, which is narrower at the top and wider at the bottom, the powder naturally concentrates downwards under gravity and slides smoothly down the cylinder wall. This avoids the problem of powder easily forming a static layer near the cylinder wall, which is common in straight cylindrical structures. The frustum-shaped structure also causes the cross-sectional area inside the cylinder to gradually increase from top to bottom, and correspondingly, the airflow velocity gradually decreases from top to bottom, forming a velocity gradient field that is conducive to the separation of coarse and fine powders. Fine powder is carried out under the action of higher airflow velocity at the top, while coarse powder settles under the action of lower airflow velocity at the bottom, achieving a natural classification function. The return powder pipe connects the upper and lower height positions of the classifying cylinder, forming a closed circulation path. After coarse powder enters the return powder pipe from the lower outlet, it is conveyed upwards along the pipe by the conveying screw, and finally re-enters the classifying cylinder from the upper feed end, completing one cycle. The gap between the spiral blades of the conveying screw and the inner wall of the pipe gradually decreases along the length direction. This design gradually enhances the constraint on the powder during transport, compressing the gaps between powder particles and increasing the bulk density. This results in a higher powder mass transported per unit time at the same spiral speed, improving transport efficiency. The cyclical squeezing and releasing action of the wavy spiral blades on the powder during rotation disrupts the static friction connection between powder particles, keeping the powder in a flowing state and reducing transport resistance. The stepped, increasing diameter of the central shaft ensures that the torsional stiffness of the shaft at different positions matches the actual torque it bears, avoiding stress concentration and over-design. The inner surface guide grooves guide the powder along a specific path, increasing the length of the powder's trajectory and residence time within the cylinder, thus enhancing the classification effect. Through structural optimization and geometric design, the entire system achieves natural powder flow and efficient transport, maximizing the use of gravitational potential energy and reducing the power consumption required for mechanical transport, thus achieving energy conservation.

Claims

1. An energy-saving closed-loop circulation structure for powder recovery in a mining powder processing equipment, comprising a classifying cylinder, a powder recovery pipeline, and a conveying screw, characterized in that... The grading cylinder has a frustum-shaped wall that is narrower at the top and wider at the bottom. A discharge port is provided at the center of the bottom of the grading cylinder. The feed end of the return powder pipe is connected to the upper part of the side wall of the grading cylinder, and the discharge end of the return powder pipe is connected to the lower part of the side wall of the grading cylinder. The conveying screw is disposed inside the return powder pipe, and a gap is formed between the spiral blades of the conveying screw and the inner wall of the return powder pipe. The width of the gap gradually decreases along the length of the return powder pipe.

2. The energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment according to claim 1, characterized in that, The inclination angle of the frustoconical wall of the grading cylinder is 15° to 30°.

3. The energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment according to claim 2, characterized in that, The connection point of the feed end of the return powder pipe on the side wall of the classifier cylinder is higher than the connection point of the discharge end of the return powder pipe on the side wall of the classifier cylinder, and the height difference between the two is 1 / 2 to 2 / 3 of the total height of the classifier cylinder.

4. The energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment according to claim 3, characterized in that, The outer edge of the spiral blades of the conveying spiral is wavy, and the distance between the crest of the wave and the inner wall of the return powder pipe is less than the distance between the trough of the wave and the inner wall of the return powder pipe.

5. The energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment according to claim 4, characterized in that, The thickness of the spiral blades of the conveying spiral gradually increases along the spiral axis, and the thickness of the spiral blades near the feed end is smaller than that near the discharge end.

6. The energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment according to claim 5, characterized in that, The powder return pipe has an arc-shaped curved structure, and the bending radius of the powder return pipe is 8 to 12 times the diameter of the powder return pipe.

7. The energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment according to claim 6, characterized in that, The discharge port edge of the grading cylinder extends inward to form an annular boss. The inner diameter of the annular boss is smaller than the outer diameter of the discharge port, and the height of the annular boss is 1 / 3 to 1 / 2 of the thickness of the bottom of the grading cylinder.

8. The energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment according to claim 7, characterized in that, The diameter of the central shaft of the conveying screw increases in a stepped manner along the axial direction, with the diameter difference between two adjacent stepped sections being 2mm to 5mm.

9. The energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment according to claim 8, characterized in that, The powder return pipe is made of stainless steel, the conveying screw is made of wear-resistant alloy steel, and the grading cylinder is made of carbon steel.

10. The energy-saving closed-loop circulation structure for returning powder in a mining powder processing equipment according to claim 9, characterized in that, The inner surface of the frustoconical wall of the grading cylinder is provided with multiple axially extending guide grooves. The depth of the guide grooves is 2mm to 4mm, and the distance between two adjacent guide grooves is 1 / 12 to 1 / 8 of the circumference of the inner wall of the grading cylinder.

Images