Low-resistance and high-efficiency multi-flow regulating static classifier and design method thereof

Abstract

The application provides a low-resistance and high-efficiency multi-flow regulation static classifier and a design method thereof. A multi-flow regulation connecting air pipe is arranged in communication with an air inlet side of an air inlet chamber of the static classifier. The multi-flow regulation connecting air pipe is located at the upper, middle and lower parts of the whole vertical section of the air inlet side. The multi-flow regulation connecting air pipe comprises a multi-flow regulation main air pipe located at the top and a plurality of multi-flow regulation branch air pipes located below the multi-flow regulation main air pipe. The pipe diameter of the multi-flow regulation main air pipe is larger than that of the multi-flow regulation branch air pipes, and the multi-flow regulation main air pipe is connected with a main air inlet of the air inlet chamber. An air inlet of the multi-flow regulation connecting air pipe is provided with a total air inlet pipe in communication therewith and capable of allowing air to be inhaled upward and downward, and the total air inlet pipe is located on the same plane as the multi-flow regulation connecting air pipe. The total air inlet pipe makes the air inlet of the classification equipment no longer affected by different arrangement types of a system circulating air pipe, simultaneously plays a role of mixing and buffering air flow, guarantees a prerequisite of classification driving force, achieves the purpose of uniform air inlet, and improves classification efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material sorting, and more particularly to a low-resistance and high-efficiency multi-flow adjusting static classifier and a design method thereof. BACKGROUND

[0002] The V-shaped static classifier is a non-powered scattering and classifying device. Due to its simple structure, convenient maintenance and high classifying efficiency, the V-shaped static classifier is widely used in a combined grinding system with a roller press, a semi-final grinding system, a final grinding system, an external circulation vertical mill system and other grinding systems. The V-shaped static classifier mainly classifies the coarse and fine particles of the material ground by the material bed grinding device. The coarse particles are returned to the material bed grinding device as return powder for regrinding, and the fine particles are used as semi-final products and then enter a subsequent fine dynamic powder selecting device or are directly collected into a ball mill for processing. If the return powder contains too many fine particles, the grinding efficiency of the material bed grinding device will be affected. If the semi-final products contain too many coarse particles, the processing efficiency of the subsequent process will be affected.

[0003] The current V-shaped static classifier adopts a single air inlet type or a single air inlet plus multiple cold air supplement air inlets. The circulating air is mainly introduced from a system circulating fan as the air volume for powder selection. The connection mode of the air inlet pipe and the V-shaped static classifier is designed differently according to the situation of each site, which easily causes uneven distribution of the airflow entering the V-shaped static classifier, affecting the classifying efficiency. The cold air supplement air inlets introduce air from the environment, affecting the effective use of the system circulating air.

[0004] According to the numerical simulation theory analysis, there are common problems of local high wind speed caused by wind short circuit at the top of the V-shaped static classifier and uneven distribution of the wind speed at the air inlet end face of the air inlet chamber. When the air flow is large, a large number of coarse particles directly enter the fine dynamic powder selecting device or the ball mill, affecting the powder selection or grinding efficiency of the subsequent process, and increasing the equipment resistance of the V-shaped static classifier itself. When the air flow is small, the classifying efficiency of the V-shaped static classifier is reduced, the content of fine powder in the return powder is increased, and more finished products are returned to the material bed grinding device, affecting the stability of the material bed and the grinding efficiency.

[0005] Chinese Patent Publication No. CN115889195A discloses a multi-particle size classifying device with a centrally coupled rotating cage and a classifying method thereof. A plurality of multi-flow air control pipes are arranged in the lower part of the static classifier to improve the uniformity of the airflow entering the static classifier. In actual application, the static classifier has multiple air inlets in the multi-flow air control pipe. When arranging the air inlets, the application is limited due to the different process system site arrangements. The arrangement of the air inlet pipe has a great influence on the airflow uniformity of the V-shaped classifier, and further affects the classifying efficiency of the device on the particles. SUMMARY

[0006] The application provides a low-resistance and high-efficiency multi-flow adjusting static classifier and a design method thereof, and aims at solving the problems of uneven air flow distribution, site limitation of air inlet pipe arrangement and poor classification efficiency of the V-shaped static classifier in the prior art.

[0007] The application provides a low-resistance and high-efficiency multi-flow adjusting static classifier, and the internal space of the shell comprises an air inlet chamber and an air outlet chamber, and the air inlet chamber and the air outlet chamber form a V-shaped structure; a plurality of step-shaped inclined guide plates are arranged in the air inlet chamber, and a plurality of step-shaped inclined classification plates are arranged in the air outlet chamber; a main air inlet is arranged at the top of the air inlet chamber, and a classifier air outlet for discharging fine powder is arranged at the top of the air outlet chamber; a coarse powder discharge outlet is arranged at the bottom of the shell, and a feeding port is arranged at the top of the shell between the air inlet chamber and the air outlet chamber.

[0008] A multi-flow adjusting connecting air pipe is arranged in communication with the air inlet side of the air inlet chamber, and the multi-flow adjusting connecting air pipe is located on the same plane as the static classifier and is located at the upper part, the middle part and the lower part of the entire vertical section of the air inlet side; the multi-flow adjusting connecting air pipe comprises a multi-flow adjusting main air pipe located at the top and a plurality of multi-flow adjusting branch air pipes located below the multi-flow adjusting main air pipe, and the multi-flow adjusting main air pipe and the multi-flow adjusting branch air pipes are arranged side by side; the pipe diameter of the multi-flow adjusting main air pipe is greater than that of the multi-flow adjusting branch air pipes, and the multi-flow adjusting main air pipe is connected with the main air inlet of the air inlet chamber.

[0009] The air inlet of the multi-flow adjusting connecting air pipe is further provided with a total air inlet pipe in communication therewith, and the total air inlet pipe is located on the same plane as the multi-flow adjusting connecting air pipe; the total air inlet pipe is connected with a system circulating air pipe; and the total air inlet pipe has an upper air inlet and / or a lower air inlet.

[0010] The classifier air outlet of the static classifier is connected with a system circulating air fan, and the air outlet of the system circulating air fan is connected with the system circulating air pipe.

[0011] Optionally, the multi-flow adjusting main air pipe and the multi-flow adjusting branch air pipes are in inverted V-shaped structures, and are arc-shaped at the bending parts.

[0012] Optionally, the included angle θ6 between the air inlet direction of the multi-flow adjusting connecting air pipe and the horizontal plane ranges from 35 to 55 degrees.

[0013] The included angle θ5 between the air outlet direction of the multi-flow adjusting connecting air pipe and the horizontal plane ranges from 20 to 35 degrees.

[0014] Optionally, the included angle θ4 between the shell of the air inlet side of the air inlet chamber and the horizontal plane ranges from 50 to 75 degrees.

[0015] Optionally, the design air volume of the multi-flow regulating main air duct accounts for 50-70% of the total air intake volume, and the design air velocity V1 of the multi-flow regulating main air duct is in the range of 12-16 m / s;

[0016] The design wind speed Vpi range of the multi-flow regulating air distribution duct is 9 to 14 m / s.

[0017] Optionally, the multi-flow regulating main air duct and the multi-flow regulating branch air duct are equipped with control valves for controlling the air volume and air speed in the corresponding air ducts.

[0018] Optionally, the cross-sectional area of ​​each of the multi-flow regulating air distribution ducts is the same or decreases from bottom to top.

[0019] Optionally, the straight line S2 where the endpoints of the plurality of guide plates are located near the air outlet chamber is parallel to the straight line S1 where the endpoints of the plurality of grading plates are located near the air inlet chamber; the channel between the straight line S1 and the straight line S2 is a material channel;

[0020] The material concentration C per unit volume of the material channel v =100~150t / hm 3 ;

[0021] The feeding port is located upstream of the top opening of the material channel and is offset; the powder return outlet is located downstream of the bottom opening of the material channel and is offset.

[0022] The feed concentration C per unit area of ​​the feed port b =1000~1400t / hm 2 .

[0023] This invention also provides a design method for a low-resistance, high-efficiency multi-flow regulating static classifier, comprising:

[0024] Determine design parameters:

[0025] Preset material throughput T, in t / h; material-to-air ratio C s The ratio of material volume to air volume passing through the static classifier per unit time, expressed in kg / m³. 3 The required air volume Q for grading is expressed in m³. 3 / h; Feed concentration per unit area of ​​feed inlet C b The unit is t / h·m 2 Material concentration per unit volume C within the material channel V The unit is t / h·m 3The following parameters are considered in meters: feed inlet length b, grading plate length L1, spacing between adjacent grading plates h1, guide plate length L2, spacing between adjacent guide plates h2, guide plate and grading plate width B, guide plate and grading plate thickness h0, and material channel width d. The gap velocity V between adjacent grading plates is also considered. f The gap speed V between the air deflector and the adjacent guide vane d All units are m / s; the angle θ1 between the grading plate and the horizontal plane, the angle θ2 between the straight line S1 containing the endpoints of the multiple grading plates near the air inlet chamber and the horizontal line, and the angle θ3 between the guide plate and the horizontal plane are all in °; the total number of grading plates n1 and the total number of guide plates n2 are all in units of one.

[0026] Based on the preset material processing capacity T, the material-to-air ratio C s The total air volume Q required for the classification is calculated using the following formula:

[0027] Q = 1000T / C s (1)

[0028] In formula (1), C s The range is 3.5–4.5 kg / m². 3 between;

[0029] Based on the preset material processing capacity T and the feeding concentration per unit area of ​​the feeding port C b The ratio of the feed inlet length b to the grading plate width B, k2, is used to calculate the width B of the guide plate and the grading plate, as follows:

[0030]

[0031] In formula (2), k2 is a constant with a value range of 0.1 to 0.2;

[0032] Based on the total air volume Q required for grading, the width B of the grading plate, the angle θ1 between the grading plate and the horizontal plane, and the gap velocity V between adjacent grading plates. f The total number of grading plates, n1, is calculated using the following formula:

[0033]

[0034] Based on the total air volume Q required for grading, the width B of the grading plate, the total number of grading plates n1, and the gap velocity V between adjacent grading plates. f Calculate the spacing h1 between adjacent grading plates using the following formula:

[0035]

[0036] Based on the preset material processing capacity T, the width B of the grading plate, the angle θ1 between the grading plate and the horizontal plane, the angle θ2 between the straight line S1 containing the endpoints of multiple grading plates near the air inlet chamber and the horizontal plane, the total number of grading plates n1, the spacing h1 between adjacent grading plates, the thickness h0 of the grading plate and guide plate, and the material concentration C per unit volume in the material channel. V The formula for calculating the material channel width d is as follows:

[0037]

[0038] Based on the total number of guide vanes n2, the total air volume Q required for grading, the width of the grading plate B, and the gap velocity V between adjacent guide vanes. d Calculate the spacing h2 between adjacent guide vanes, where n2 = n1 ± (0 ~ 2), using the following formula:

[0039]

[0040] The length L2 of the guide plate is calculated based on the spacing h2 between adjacent guide plates, the thickness h0 of the grading plate and the guide plate, the angle θ2 between the straight line S1 containing the endpoints of the multiple grading plates near the air inlet chamber and the horizontal plane, and the angles θ3 and k3 between the guide plate and the horizontal plane. The formula is as follows:

[0041]

[0042] In formula (7), K3 is a constant with a value range of 0.6 to 0.9.

[0043] Optionally, it also includes:

[0044] The distance from the end face of the main air inlet to the top guide plate is determined to be L3, and the value of L3 is in the range of 1000 to 1500 mm;

[0045] The width L4 of the multi-flow regulating main duct is calculated based on the total air volume Q required for grading, the width B of the grading plate, and the air velocity V1 of the multi-flow regulating main duct, using the following formula:

[0046]

[0047] In formula (8), k4 is a constant with a value range of 0.5 to 0.7;

[0048] Based on the width L4 of the multi-flow regulating main duct, the distance h2 between adjacent guide vanes, and the thickness h0 of the grading plate and guide vanes, calculate the number n3 of guide vanes within the projected range corresponding to the width L4 of the multi-flow regulating main duct, using the following formula:

[0049]

[0050] Based on the number of guide vanes n2 and the number of guide vanes n3 within the projected range corresponding to the width L4 of the multi-flow regulating main duct, calculate the number of multi-flow regulating branch ducts n4, using the following formula:

[0051]

[0052] Based on the total air volume Q required for grading, the width B of the grading plate, the number of multi-flow regulating ducts n4, the design air velocity Vpi of the multi-flow regulating ducts, and the k4 constant, the length Lpi of the multi-flow regulating duct is calculated using the following formula:

[0053]

[0054] In formula (11), i=1, 2,..., n4;

[0055] In formulas (8), (9), (10), and (11), the wind speed V1 of the multi-flow regulating main duct and the design wind speed Vpi of the multi-flow regulating branch duct are both in m / s; the width L4 of the multi-flow regulating main duct and the length Lpi of the multi-flow regulating branch duct are both in m; the number of guide vanes n3 and the number of multi-flow regulating branch ducts n4 corresponding to the projection of the width L4 of the multi-flow regulating main duct are both in units.

[0056] Optionally, the method further includes using numerical simulation to theoretically analyze the designed static classifier. If the classification efficiency of the static classifier is less than the target efficiency, the parameters with a range of values ​​are re-valued within the corresponding range until the classification efficiency of the static classifier obtained from the theoretical analysis is greater than or equal to the target efficiency.

[0057] The present invention has at least the following beneficial effects:

[0058] This invention provides a low-resistance, high-efficiency multi-flow adjustable static classifier and its design method. A multi-flow adjustable connecting duct, located on the same plane as the static classifier, is connected to the air inlet side of the air inlet chamber. The multi-flow adjustable connecting duct is situated at the upper, middle, and lower parts of the entire vertical section on the air inlet side. The multi-flow adjustable connecting duct includes a main multi-flow adjustable duct at the top and multiple branch multi-flow adjustable ducts below it, arranged side-by-side. The diameter of the main multi-flow adjustable duct is larger than that of the branch multi-flow adjustable ducts, and the main multi-flow adjustable duct is connected to the main air inlet of the air inlet chamber. After the multi-flow regulating connecting duct is connected to the airflow, most of the airflow enters the multi-flow regulating main duct with a larger cross-section, and a portion of the airflow enters the multi-flow regulating branch duct. Thus, the airflow enters the upper, middle and lower parts of the entire vertical section of the air inlet side from the multi-flow regulating main duct and the multi-flow regulating branch duct. While meeting the airflow driving force requirements of the static classifier, it also achieves the purpose of uniform air intake and improves the classification efficiency.

[0059] In addition, the air intake of the static classifier is no longer affected by the different layouts of the system's circulating air ducts. The main air intake duct plays the role of mixing and buffering airflow, making the airflow entering the static classifier more uniform in the width direction. At the same time, the static classifier makes full use of the system's circulating air, maintaining the pressure balance of the entire grinding system and reducing equipment and system resistance as well as system fan energy consumption. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 This is a three-dimensional schematic diagram of the static grading machine of the present invention;

[0062] Figure 2 This is a schematic diagram of the air intake method of the static classifier of the present invention;

[0063] Figure 3 This is a schematic diagram of the static grading machine of the present invention;

[0064] Figure 4 This is a schematic diagram of the static classifier guide plate and classifier plate structure of the present invention;

[0065] Figure 5 This is a numerical analysis diagram of the static classifier before multi-flow control according to the present invention;

[0066] Figure 6 This is a numerical analysis diagram of the static classifier after multi-flow control according to the present invention;

[0067] Figure 7 This is a trend diagram of wind speed distribution before and after the multi-flow regulation of the present invention, showing the wind speed distribution of the guide vanes and grading plates.

[0068] Figure 8 This is a comparison chart of the efficiency of powder particle selection before and after multi-flow control of the static classifier of the present invention.

[0069] Attached reference numerals: 1. Main air inlet duct; 2. Multi-flow regulating main air duct; 3. Feed port; 4. Classifier outlet; 5. Shell; 6. Classifying plate; 7. Return powder outlet; 8. Guide plate; 9. Multi-flow regulating branch air duct; 10. Multi-flow regulating main air duct control valve; 11. Multi-flow regulating branch air duct valve; 12. System circulating fan; 13. System circulating air duct. Detailed Implementation

[0070] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0071] This invention provides a low-resistance, high-efficiency multi-flow adjustable static classifier. The internal space of the housing 5 includes an air inlet chamber and an air outlet chamber, which form a V-shaped structure. The air inlet chamber is provided with multiple stepped inclined guide plates 8, and the air outlet chamber is provided with multiple stepped inclined classifying plates 6. The top of the air inlet chamber is provided with a main air inlet, and the top of the air outlet chamber is provided with a classifier air outlet 4 for fine powder discharge. The bottom of the housing 5 is provided with a powder return outlet 7 for coarse powder discharge, and the top of the housing 5 is provided with a feeding port 3 located between the air inlet chamber and the air outlet chamber.

[0072] The air inlet chamber is connected to a multi-flow regulating connecting duct on the air inlet side. The multi-flow regulating connecting duct is on the same plane as the static classifier and is located at the upper, middle, and lower parts of the entire vertical section on the air inlet side. The multi-flow regulating connecting duct includes a multi-flow regulating main duct 2 at the top and multiple multi-flow regulating branch ducts 9 below the multi-flow regulating main duct. The multi-flow regulating main duct 2 and the multi-flow regulating branch ducts 9 are arranged side by side. The diameter of the multi-flow regulating main duct 2 is larger than the diameter of the multi-flow regulating branch ducts 9. The multi-flow regulating main duct 2 is connected to the main air inlet of the air inlet chamber.

[0073] The air inlet of the multi-flow regulating connecting air duct is also provided with a main air inlet duct 1 connected thereto. The main air inlet duct 1 and the multi-flow regulating connecting air duct are located on the same plane. The main air inlet duct 1 is connected to the system circulation air duct 13. The main air inlet duct 1 has an upper air inlet and / or a lower air inlet.

[0074] The air outlet of the static classifier is connected to the system circulating fan 12, and the air outlet of the system circulating fan 12 is connected to the system circulating duct 13.

[0075] Specifically, the feed inlet 3 of the multi-flow regulating static classifier is located at the top of the intersection of the V-shaped structure formed by the inlet and outlet chambers, and the material is fed into the classifier through the feed inlet 3. After entering the inlet chamber, the material begins to disperse under the action of airflow. Multiple stepped, inclined guide plates 8 are installed in the inlet chamber, which help to evenly distribute the airflow and initially classify the material. The material then enters the outlet chamber with the airflow, where multiple stepped, inclined classifying plates 6 are installed. These classifying plates 6 further classify the material particles according to their size and weight. Larger particles, due to their greater weight and size, slide downwards along the classifying plates 6 and are eventually discharged through the bottom powder return outlet 7. Smaller particles are discharged through the gaps between the classifying plates 6 and the classifier outlet 4, collecting the required fine powder.

[0076] The multi-flow regulating connecting duct is on the same plane as the static classifier and is located at the top, middle, and bottom of the entire vertical section on the air inlet side. This allows the static classifier to achieve uniform air intake in the vertical plane, preventing all airflow from concentrating at the top of the static classifier. The diameter of the multi-flow regulating main duct 2 at the top of the multi-flow regulating connecting duct is larger than that of the multi-flow regulating branch duct 9. As the main air intake channel of the air inlet chamber, the multi-flow regulating main duct 2 needs to ensure sufficient airflow intensity to drive the movement and dispersion of materials within the classifier. The larger duct diameter reduces airflow resistance during transmission, ensuring that the main airflow can enter the air inlet chamber smoothly and efficiently.

[0077] The inlet of the multi-flow regulating connecting duct is connected to the main inlet duct 1, which in turn connects to the system circulation duct 13. The system circulation duct 13 is not directly connected to the static classifier. The main inlet duct 1 is connected to the system circulation duct 13. The main inlet duct 1 has the function of top air intake and / or bottom air intake. Therefore, the air intake of the static classifier is no longer affected by different arrangement of the system circulation duct 13. The static classifier has a main inlet duct 1 at its air inlet, which can be used for top air intake or bottom air intake. The circulating airflow can be entered from 360°, and it plays a role in mixing and buffering the circulating airflow into the static classifier. It also facilitates various on-site process arrangements and makes the airflow in the width direction of the static classifier more uniform. Under the suction of the system circulation fan 12, the gas containing fine powder is discharged from the classifier outlet of the static classifier. The gas after the fine powder is collected is re-entered into the main inlet duct 1 by the circulation fan to achieve air circulation. The air entering the main air inlet duct 1 enters the multi-flow regulating main air duct 2 and the multi-flow regulating branch air duct 9 respectively. The outlets of the multi-flow regulating main air duct 2 and the multi-flow regulating branch air duct 9 enter the housing 5 to classify the material fed in from the feed port 3.

[0078] If the multi-flow regulating air distribution duct does not use system recirculation air, but instead uses ambient air intake (cold air inlet), there are structural drawbacks: 1. Most of the air still enters from the upper main air duct, and the problems caused by the high-speed airflow at the top of the static classifier remain unresolved unless many cold air inlets are added below, with a ventilation area comparable to the main air inlet, which introduces other problems. 2. For systems with high raw material moisture content, the drying effect of cold air intake is greatly reduced, potentially requiring additional heat sources and increasing energy consumption. 3. The total air volume required by the system is fixed, meaning the total air volume entering the recirculating fan is constant. Ideally, 70%–80% of the recirculated air could be used for system operation to save energy while providing a heat source for drying the mixed materials. The remaining 20%–30% of the air is discharged into the atmosphere through the subsequent tail exhaust process section for further dust collection and removal of system moisture to prevent condensation. If more cold air is introduced, the amount of air entering the exhaust fan will be greater than before, because the main system needs to maintain a constant air volume. This increases the energy consumption of the exhaust fan. In addition, with more cold air introduced, the air becomes heavier, making it more difficult to operate the circulating fan, which may also increase the energy consumption of the circulating fan and increase production costs.

[0079] If the multi-flow regulating air distribution duct fully utilizes the original circulating air, and through multi-flow air control methods, the resistance of the static classifier will decrease, thereby reducing the system resistance. Under the condition that the system air volume remains unchanged, the energy consumption of the circulating fan will also decrease.

[0080] In one possible implementation, both the multi-flow regulating main duct and the multi-flow regulating branch duct have an inverted V-shaped structure and an arc transition at the bend.

[0081] Specifically, the multi-flow regulating connecting duct has an inverted V-shaped structure with an arc transition at the bend. This arc transition reduces turbulence and vortices in the airflow during transmission. These turbulence and vortices not only increase energy loss but can also affect the uniform distribution of airflow. Furthermore, the smooth transition design of the bend reduces variations in airflow velocity and the degree of turbulence, thereby ensuring a uniform airflow distribution.

[0082] In one possible implementation, the angle θ6 between the air inlet direction of the multi-flow regulating connecting duct and the horizontal plane is in the range of 35° to 55°.

[0083] The angle θ5 between the outlet direction of the multi-flow regulating connecting duct and the horizontal plane ranges from 20° to 35°. A suitable angle range helps reduce energy loss during airflow transmission and improves the system's energy efficiency.

[0084] In one possible implementation, the angle θ4 between the inlet side shell of the air inlet chamber and the horizontal plane ranges from 50° to 75°. This allows for a wider distribution of airflow in the vertical plane in the multi-flow regulating main duct, while ensuring effective continuity of airflow in the multi-flow regulating branch ducts. This enhances the guiding effect of the air inlet chamber, thereby improving the material classification effect and accuracy. By setting the angle between the inlet side shell of the air inlet chamber and the horizontal plane, a convergence angle is provided for the multi-flow regulating ducts. If the angle of the inlet side shell is too large, the contribution of the incident airflow in the bottom multi-flow regulating branch duct 9 to the guiding effect decreases, and the downward guiding effect of the top multi-flow regulating main duct 2 also decreases. If the angle of the inlet shell is too small, it is not conducive to the arrangement of the multi-flow regulating branch duct 9.

[0085] In one possible implementation, the design airflow of the multi-flow regulating main duct 2 accounts for 50-70% of the total air intake, and the design air velocity V1 of the multi-flow regulating main duct 2 ranges from 12 to 16 m / s; the design air velocity Vpi of the multi-flow regulating branch duct 9 ranges from 9 to 14 m / s. The design airflow of the main duct accounting for 50-70% of the total air intake means that the system can effectively distribute most of the airflow to the multi-flow regulating main duct 2, while the remaining airflow is distributed to other locations in the air intake chamber through the multi-flow regulating branch duct 9, ensuring reasonable airflow distribution and avoiding excessive or insufficient airflow in certain areas. If the design airflow of the multi-flow regulating main duct 2 exceeds this range, the airflow of the multi-flow regulating branch duct 9 will be too small, failing to achieve uniform airflow and resulting in poorer sorting performance.

[0086] In one possible implementation, the multi-flow regulating main air duct 2 and the multi-flow regulating branch air duct 9 are equipped with control valves for controlling the air volume and air speed in the corresponding air ducts.

[0087] Specifically, a multi-flow regulating main air duct 2 is equipped with a multi-flow regulating main air duct control valve 10, and a multi-flow regulating branch air duct 9 is equipped with a multi-flow regulating branch air duct control valve 11. These control valves can precisely regulate the airflow within their respective ducts, ensuring that the air volume and velocity meet specific process requirements or equipment needs. Furthermore, by adjusting the control valves on different ducts, differentiated control of air volume and velocity in different areas of the duct system can be achieved to meet various production or ventilation requirements.

[0088] In one possible implementation, the cross-sectional area of ​​the multi-flow regulating duct 9 is the same or decreases from bottom to top.

[0089] Specifically, the cross-sectional area of ​​the multi-flow regulating air distribution duct 9 can be designed to be the same or different according to the actual classification requirements. When the cross-sectional areas are different, the cross-sectional areas of the multiple multi-flow regulating air distribution ducts 9 decrease from bottom to top.

[0090] In one possible implementation, the straight line S2 where the endpoints of the plurality of guide plates 8 are near the air outlet chamber is parallel to the straight line S1 where the endpoints of the plurality of grading plates 6 are near the air inlet chamber; the channel between the straight line S1 and the straight line S2 is a material channel.

[0091] The material concentration C per unit volume of the material channel v =100~150t / hm 3 ;

[0092] The feeding port 3 is located upstream of the top opening of the material channel and is offset; the powder return outlet is located downstream of the bottom opening of the material channel and is offset.

[0093] The feed concentration C per unit area of ​​the feed port b =1000~1400t / hm 2 .

[0094] Specifically, the design of the guide plate 8 and the classifying plate 6 creates a clear material channel within the static classifier, facilitating the orderly flow and separation of materials during the classification process. Furthermore, the staggered feeding port 3 at the top of the material channel prevents newly added material from directly entering the critical classification area of ​​the classifier, which could affect the classification effect of materials already in the process. By staggering the feeding port 3 from the channel inlet, newly added material first falls into a buffer zone and then gradually enters the classification area, reducing direct interference. The staggered return outlet at the bottom of the material channel prevents coarse particles from flowing directly out of the bottom opening and being discharged directly from the return powder outlet 7, causing insufficiently classified material to be prematurely removed from the static classifier and reducing classification efficiency. Through this staggered arrangement, coarse particles are first carried to a higher position by gravity and airflow, and then gradually fall to the return outlet, increasing the opportunity and time for classification.

[0095] Material channel design is crucial for V-type static classifiers. Material overload will affect classification efficiency and the penetration effect of the incoming airflow. Conventional designs often rely on empirical values. This invention introduces volume concentration and area concentration parameters to better guide the design.

[0096] This invention also provides a design method for a low-resistance, high-efficiency multi-flow regulating static classifier, applicable to the static classifier of this invention, comprising:

[0097] Determine design parameters:

[0098] Preset material throughput T, in t / h; material-to-air ratio C sThe ratio of material volume to air volume passing through the static classifier per unit time, expressed in kg / m³. 3 The required air volume Q for grading is expressed in m³. 3 / h; Feeding concentration C per unit area at the feeding port 3 b The unit is t / h·m 2 The concentration of material per unit volume C in the material channel V The unit is t / h·m 3 The following parameters are considered: feed inlet 3 length b, grading plate 6 length L1, spacing between adjacent grading plates 6 h1, grading plate guide plate 8 length L2, spacing between adjacent guide plates 8 h2, width of guide plate 8 and grading plate 6 B, thickness of guide plate 8 and grading plate 6 h0, and material channel width d. All units are in meters. The gap velocity V between adjacent grading plates 6 is also considered. f The gap wind speed V between the air deflector 8 and the adjacent guide vane 8 d All units are m / s; the acute angle θ1 between the grading plate 6 and the horizontal plane, the angle θ2 between the straight line S1 where the endpoints of the multiple guide plates 8 are located near the air outlet chamber and the horizontal line, and the angle θ3 between the guide plate 8 and the horizontal plane, are all in °; the total number of grading plates 6 n1 and the total number of guide plates 8 n2 are all in units.

[0099] The preset material throughput of a static classifier refers to the amount of raw materials that the static classifier is designed or manufactured to process within a certain time frame. The required airflow for static classification refers to the airflow rate required by the static classifier to achieve the desired classification effect during the classification process. In this application, the width of the classifying plate 6 is the same as the internal space width of the housing 5, both being B, meaning that the two end faces of the classifying plate 6 in the width direction are in contact with the inner wall of the housing 5 in the width direction.

[0100] Based on the preset material processing capacity T, the material-to-air ratio C s The total air volume Q required for the classification is calculated using the following formula:

[0101] Q = 1000T / C s (1)

[0102] In formula (1), C s The range is 3.5–4.5 kg / m². 3 .

[0103] Based on the preset material processing capacity T and the feeding concentration C per unit area of ​​the feeding port 3. b The ratio of the length b of the feed inlet 3 to the width B of the grading plate 6, k2, is used to calculate the width B of the grading plate 6, as follows:

[0104]

[0105] In formula (2), k2 is a constant with a value range of 0.1 to 0.2;

[0106] Based on the total air volume Q required for grading, the width B of the grading plate 6, the angle θ1 between the grading plate 6 and the horizontal plane, and the gap velocity V between adjacent grading plates 6. f Calculate the total number n1 of the grading plates 6 using the following formula:

[0107]

[0108] Based on the total air volume Q required for grading, the width B of the grading plate 6, the total number n1 of the grading plates 6, and the gap velocity V between adjacent grading plates 6. f Calculate the spacing h1 between adjacent grading plates 6 using the following formula:

[0109]

[0110] Based on the preset material processing capacity T, the width B of the grading plate 6, the angle θ1 between the grading plate 6 and the horizontal plane, the angle θ2 between the straight line S1 containing the endpoints of the multiple grading plates 6 near the air inlet chamber and the horizontal plane, the total number n1 of the grading plates 6, the spacing h1 between adjacent grading plates 6, the thickness h0 of the grading plate 6 and the guide plate 8, and the material concentration per unit volume C in the material channel. V The formula for calculating the material channel width d is as follows:

[0111]

[0112] Based on the total number of guide vanes 8 n2, the total air volume Q required for grading, the width B of the grading plate 6, and the gap velocity V between adjacent guide vanes 8 d Calculate the spacing h2 between adjacent guide vanes 8, where n2 = n1 ± (0 ~ 2), using the following formula:

[0113]

[0114] Based on the spacing h2 between adjacent guide vanes 8, the thickness h0 of the grading plate 6 and guide vane 8, the angle θ2 between the straight line S1 containing the endpoints of the multiple grading plates 6 near the air inlet chamber and the horizontal plane, and the angles θ3 and k3 between the guide vane 8 and the horizontal plane, the length L2 of the guide vane 8 is calculated using the following formula:

[0115]

[0116] In formula (7), K3 is a constant with a value range of 0.6 to 0.9.

[0117] In one possible implementation, it also includes:

[0118] The distance from the main air inlet end face to the top guide plate is determined to be L3, with a value ranging from 1000 to 1500 mm. A suitable value for L3 helps ensure uniform airflow distribution within the classifier. Too small a value may lead to overly concentrated airflow, increasing local pressure loss, while too large a value may cause airflow dispersion, affecting the classification effect or ventilation efficiency. Within the given range of 1000 to 1500 mm, the airflow can pass more stably through the air inlet of the outlet duct and be evenly distributed to the top guide plate 8, thereby optimizing the airflow distribution of the entire system.

[0119] The width L4 of the multi-flow regulating main duct 2 is calculated based on the total air volume Q required for grading, the width B of the grading plate 6, and the air velocity V1 of the multi-flow regulating main duct 2, using the following formula:

[0120]

[0121] In formula (8), k4 is a constant with a value range of 0.5 to 0.7;

[0122] Based on the width L4 of the multi-flow regulating main duct 2, the spacing h2 between adjacent guide plates 8, the thickness h0 of the grading plate 6 and the guide plate 8, the number n3 of guide plates 8 within the projected range corresponding to the width L4 of the multi-flow regulating main duct 2 is calculated using the following formula:

[0123]

[0124] Based on the number of guide vanes 8 (n2) and the number of guide vanes within the projected range corresponding to the width L4 of the multi-flow regulating main air duct 2 (n3), calculate the number of multi-flow regulating branch air ducts 9 (n4) using the following formula:

[0125]

[0126] Formula (10) ensures that the multi-flow regulating air distribution duct 9 is reasonably arranged at the vertical height on the air inlet side, avoiding wasted space or excessive crowding. This helps to optimize the distribution and flow of airflow and improve the efficiency of air classification.

[0127] Based on the total air volume Q required for grading, the width B of the grading plate 6, the number n4 of the multi-flow regulating air distribution ducts 9, the design air velocity Vpi of the multi-flow regulating air distribution ducts 9, and the constant k4, the length Lpi of the multi-flow regulating air distribution ducts 9 is calculated using the following formula:

[0128]

[0129] In formula (10), i=1, 2,..., n4;

[0130] In formulas (8), (9), (10), and (11), the wind speed V1 of the multi-flow regulating main duct 2 and the design wind speed Vpi of the multi-flow regulating branch duct 9 are both in m / s; the width L4 of the multi-flow regulating main duct 2 and the length Lpi of the multi-flow regulating branch duct 9 are in m; the number of guide plates n3 and the number of multi-flow regulating branch ducts n4 corresponding to the width L4 of the multi-flow regulating main duct are in units of each.

[0131] In one possible implementation, the static classifier is theoretically analyzed using numerical simulation. If the classification efficiency of the static classifier is less than the target efficiency, the parameters with a range of values ​​are re-valued within the corresponding range until the classification efficiency of the static classifier obtained from the theoretical analysis is greater than or equal to the target efficiency.

[0132] Specifically, numerical simulation allows for the prediction and analysis of the performance of a static classifier without manufacturing an actual prototype, reducing the time required for physical prototype manufacturing and testing, and improving design efficiency. When simulation results show that the classification efficiency is lower than the target efficiency, designers can adjust design parameters, such as the number of guide vanes, to optimize the classification efficiency. This iterative design process ensures that the final design meets or exceeds the expected classification efficiency target.

[0133] By designing various parameters of the classifier, it is possible to ensure that the equipment achieves predetermined performance indicators during operation, such as grading efficiency, processing capacity, and energy consumption. Precise adjustment of these parameters optimizes the overall performance of the equipment, making it more efficient and stable in practical applications. A well-designed parameter system ensures the classifier maintains stability and reliability during long-term operation. Furthermore, reducing unnecessary energy loss and improving energy utilization efficiency can lower operating costs, and a well-designed parameter system can reduce the classifier's energy consumption.

[0134] The present invention has the following advantages and beneficial effects:

[0135] 1) The present invention sets up a main air inlet pipe 1 connected to the system circulation air pipe 13. The system circulation air pipe 13 is not directly connected to the static grading equipment. The air intake of the static grading equipment is no longer affected by the different arrangement of the system circulation air pipe 13. The main air inlet pipe 1 plays the role of mixing and buffering airflow, making the airflow entering the static grading machine more uniform in the width direction.

[0136] 2) The present invention sets up multiple balanced dynamic air control pipes between the static grading equipment and the main air inlet pipe 1 to solve the problem of local high wind speed at the top of the original V-shaped static grading equipment, so that the airflow in the height direction of the static grading equipment is more uniform and the grading efficiency is improved; the static grading machine makes full use of the system circulating air to maintain the pressure balance of the entire grinding system, while reducing the resistance of the equipment and system and the energy consumption of the system fan.

[0137] 3) This invention can quickly upgrade and transform existing V-type static grading systems on the market, effectively saving transformation time and costs.

[0138] The drag reduction effect of the static classifier designed according to the embodiment of this invention, verified by CFD numerical calculation, is shown in Table 1. The airflow uniformity at the inlet face of the inlet chamber is as follows: Figures 5 to 7 As shown, the efficiency of powder particle separation is as follows: Figure 8 As shown.

[0139] Table 1 Comparison of equipment resistance before and after multi-flow regulation.

[0140]

[0141] As shown in Table 1, under the same air volume and other control parameters, the resistance of the static classifier designed according to the embodiment of the present invention is reduced by 23% after multi-flow regulation. Figures 5 to 7 The airflow velocity distribution at the inlet face of the static classifier's air inlet chamber shows that, after multi-flow control, the average airflow velocity between the classifier plate 6 and the guide plate 8 is more uniform across the entire vertical air inlet face. Figure 8 A comparison of the selection efficiency of particles of different sizes in the returned powder from the static classifier shows that after multi-flow control, the number of coarse particles in the returned powder increases and the number of fine particles decreases. Among them, the selection efficiency of 45μm particles in the returned powder decreases by 3.4%, indicating that the fine powder separation effect of the static classifier is improved.

[0142] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0143] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A low-resistance, high-efficiency multi-flow regulating static classifier, characterized in that: A multi-flow regulating connecting duct is installed on the air inlet side of the air inlet chamber. The multi-flow regulating connecting duct is on the same plane as the static classifier and is located in the upper, middle and lower parts of the entire vertical section on the air inlet side. The multi-flow regulating connecting duct includes a multi-flow regulating main duct at the top and multiple multi-flow regulating branch ducts below the multi-flow regulating main duct. The multi-flow regulating main duct and the multi-flow regulating branch ducts are arranged side by side. The diameter of the multi-flow regulating main duct is larger than the diameter of the multi-flow regulating branch ducts. The multi-flow regulating main duct is connected to the main air inlet of the air inlet chamber. The air inlet of the multi-flow regulating connecting air duct is also provided with a main air inlet duct connected to it. The main air inlet duct and the multi-flow regulating connecting air duct are located on the same plane. The main air inlet duct is connected to the system circulation air duct. The main air inlet duct has an upper air inlet and a lower air inlet. The air outlet of the static classifier is connected to the system circulating fan, and the air outlet of the system circulating fan is connected to the system circulating duct. A design method for a low-resistance, high-efficiency multi-flow controlled static classifier, including determining design parameters: Calculate the total air volume Q required for the classification, in m³. 3 / h; the calculation formula is: Q=1000T / C s (1) In formula (1), T is the preset material processing capacity, in t / h; the material-to-air ratio C s C is the ratio of the amount of material passing through the static classifier per unit time to the amount of air. s The range is 3.5~4.5 kg / m 3 between; Calculate the width B of the guide vane and the stager plate, in meters; the formula is as follows: B= （2） In formula (2), C b This refers to the feed concentration per unit area of ​​the feed inlet, expressed in t / h·m². 2 k2 is the ratio of the feed inlet length b to the grading plate width B. k2 is a constant with a value range of 0.1 to 0.

2. Calculate the total number of grading plates, n1, in units; the formula is as follows: n1=Round( )(3) In formula (3), θ1 is the angle between the grading plate and the horizontal plane, in degrees; V f The gap velocity between adjacent grading plates is expressed in m / s. Calculate the spacing h1 between adjacent grading plates, in meters; the formula is as follows: h1= （4） Calculate the material channel width d, in meters; the formula is as follows: d= （5） In formula (5), θ2 is the angle between the straight line S1 containing the endpoints of the multiple grading plates near the air inlet chamber and the horizontal plane, in degrees; h0 is the thickness of the grading plates and guide plates, in meters; C V The concentration of material per unit volume within the material channel, expressed in t / h·m³. 3 ; Calculate the distance h2 between adjacent guide vanes, in meters; the formula is as follows: h2= （6） In formula (6), n2 is the total number of guide vanes, n2=n1±(0~2); the gap velocity V between adjacent guide vanes d The unit is m / s; Calculate the length L2 of the deflector plate, in meters; the formula is as follows: L2= （7） In formula (7), θ3 is the angle between the guide plate and the horizontal plane, in °; K3 is a constant, with a value range of 0.6~0.

9.

2. The low-resistance, high-efficiency multi-flow regulating static classifier according to claim 1, characterized in that, Both the multi-flow regulating main air duct and the multi-flow regulating branch air duct have an inverted V-shaped structure and an arc transition at the bend.

3. The low-resistance, high-efficiency multi-flow regulating static classifier according to claim 1, characterized in that, The angle θ6 between the air inlet direction of the multi-flow regulating connecting duct and the horizontal plane is in the range of 35~55°; The angle θ5 between the air outlet direction of the multi-flow regulating connecting duct and the horizontal plane ranges from 20° to 35°.

4. The low-resistance, high-efficiency multi-flow regulating static classifier according to claim 1, characterized in that, The angle θ4 between the air inlet side shell of the air inlet chamber and the horizontal plane ranges from 50 to 75°.

5. The low-resistance, high-efficiency multi-flow regulating static classifier according to claim 1, characterized in that, The design air volume of the multi-flow regulating main air duct accounts for 50-70% of the total air intake volume, and the design air velocity V1 of the multi-flow regulating main air duct is in the range of 12-16m / s. The design wind speed Vpi range of the multi-flow regulating air distribution duct is 9~14m / s.

6. The low-resistance, high-efficiency multi-flow regulating static classifier according to claim 1, characterized in that, The multi-flow regulating main air duct and the multi-flow regulating branch air duct are equipped with control valves for controlling the air volume and air speed in the corresponding air ducts.

7. The low-resistance, high-efficiency multi-flow regulating static classifier according to claim 1, characterized in that, All of the aforementioned multi-flow regulating air distribution ducts have the same cross-sectional area or the cross-sectional area decreases from bottom to top.

8. The low-resistance, high-efficiency multi-flow regulating static classifier according to claim 1, characterized in that, The straight line S2, where the endpoints of the multiple guide plates are located near the air outlet chamber, is parallel to the straight line S1, where the endpoints of the multiple grading plates are located near the air inlet chamber; the channel between the straight line S1 and the straight line S2 is a material channel. The material concentration C per unit volume of the material channel v =100~150 t / h·m 3 ; The feeding port is located upstream of the top opening of the material channel and is offset; the return powder outlet is located downstream of the bottom opening of the material channel and is offset. The feed concentration C per unit area of ​​the feed port b =1000~1400 t / h·m 2 .

9. A low-resistance, high-efficiency multi-flow regulating static classifier according to claim 1, characterized in that, The design methodology also includes: The distance from the main air inlet end face to the top guide plate is determined to be L3, and the value of L3 is in the range of 1000~1500mm; The width L4 of the multi-flow regulating main duct is calculated based on the total air volume Q required for grading, the width B of the grading plate, and the air velocity V1 of the multi-flow regulating main duct, using the following formula: L4= （8） In formula (8), k4 is a constant with a value range of 0.5 to 0.7; Based on the width L4 of the multi-flow regulating main duct, the distance h2 between adjacent guide vanes, and the thickness h0 of the grading plate and guide vanes, calculate the number n3 of guide vanes within the projected range corresponding to the width L4 of the multi-flow regulating main duct, using the following formula: n3= (9) Based on the number of guide vanes n2 and the number of guide vanes n3 within the projected range corresponding to the width L4 of the multi-flow regulating main duct, calculate the number of multi-flow regulating branch ducts n4, using the following formula: n4=Round( );(10) Based on the total air volume Q required for grading, the width B of the grading plate, the number of multi-flow regulating ducts n4, the design air velocity Vpi of the multi-flow regulating ducts, and the k4 constant, the length Lpi of the multi-flow regulating duct is calculated using the following formula: Lpi= (11) In formula (11), i=1, 2,..., n4; In formulas (8), (9), (10), and (11), the wind speed V1 of the multi-flow regulating main duct and the design wind speed Vpi of the multi-flow regulating branch duct are both in m / s; the width L4 of the multi-flow regulating main duct and the length Lpi of the multi-flow regulating branch duct are both in m; the number of guide vanes n3 and the number of multi-flow regulating branch ducts n4 corresponding to the projection of the width L4 of the multi-flow regulating main duct are both in units.

10. A low-resistance, high-efficiency multi-flow regulating static classifier according to claim 9, characterized in that, The design method also includes using numerical simulation to theoretically analyze the designed static classifier. If the classification efficiency of the static classifier is less than the target efficiency, the parameters with a range of values ​​are re-valued within the corresponding range until the classification efficiency of the static classifier obtained from the theoretical analysis is greater than or equal to the target efficiency.

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