Static blade for self-settling efficient powder concentrator, design method and efficient powder concentrator

Abstract

The invention provides a stator blade for a self-settling efficient powder concentrator. The stator blade is composed of a plurality of stator blade units. The stator blade unit is sequentially divided into an inlet section, a middle section and an outlet section in the airflow direction, and the middle section comprises a first straight flow channel and at least one set of arc-shaped flow channels. The inlet section is a trapezoidal runner, and the inlet section, the first straight runner and the outlet section are sequentially communicated; an inlet of the first straight flow channel is communicated with an inlet of the arc-shaped flow channel, an outlet of the first straight flow channel is communicated with an outlet of the arc-shaped flow channel, and airflow passing through the outlet of the arc-shaped flow channel is opposite to airflow in the first straight flow channel in direction, so that materials in the airflow are settled. According to the stator blade unit for the self-settling efficient powder concentrator, the arc-shaped flow channel is formed in the middle section, airflow carrying fine powder materials can be divided into two or three symmetrical airflow, the airflow enters different airflow channels, and through the side wall effect of the arc-shaped flow channel and airflow direction change, the fine powder materials can be separated from the airflow channels. Fine powder particles in airflow are further gathered and settled, and the powder selecting efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of powder grinding, and in particular relates to a stationary blade for a self-sedimentation high-efficiency powder classifier, a design method and a high-efficiency powder classifier. Background Art

[0002] In the field of grinding technology, the powder classifier, as a key powder classification and powder selection equipment, plays a vital role in the power, steel, cement and energy industries. With the application of the circle flow ball mill system, the powder classifier technology has been continuously developed, and has evolved from centrifugal powder classifier (first generation), cyclone powder classifier (second generation) to high-efficiency cage powder classifier (third generation). With its efficient sorting ability, the high-efficiency cage powder classifier is widely used in ball mills, roller presses and vertical mill systems to meet the grinding needs of different materials and fineness products.

[0003] Since the advent of the high-efficiency cage powder separator, after more than 30 years of development, its structure has been constantly evolving, and the product types have emerged in an endless stream, but its core principle has remained basically unchanged. The powder separator consists of fixed stationary blades and an internal cage rotor. The stationary blades are evenly distributed around the rotor's moving blades and maintain a certain spacing. The airflow with powder first passes through the periphery of the stationary blades. Under the action of the stationary blades, the airflow changes its direction and collides, thereby achieving the first sorting. The coarser particles will return along the original path, while the finer particles enter the moving blades for secondary sorting.

[0004] The moving blades are composed of blades of different shapes evenly distributed on the central spindle. By adjusting the spindle speed, moving blades with different set diameters can generate different centrifugal forces. The material particles are sorted for the second time under the balance of gas carrying force, material weight and rotor centrifugal force. Qualified materials will enter the finished product collection device, while unqualified materials will be sent back to the coarse particle collection cone of the powder classifier and fall into the grinding disc for re-grinding.

[0005] However, after industrial production practice and theoretical analysis, the high-efficiency cage powder separator has many problems and shortcomings:

[0006] First, the initial powder selection ability of its stationary blades is weak, which makes it easy for coarse particles to escape into the primary and secondary powder selection machine areas, resulting in a higher proportion of coarse particles in the finished product, and a coarser specific surface area and fineness.

[0007] Second, the powder selection load of the moving blades is too large and the linear speed of the powder selection machine is too fast, resulting in problems such as low powder selection efficiency and low powder selection clarity.

[0008] Third, when the stationary blades change the direction of airflow, they suffer greater local wear and have a short service life.

[0009] Fourth, when grinding materials such as cement that have high requirements for particle grading, the dynamic and static blades are not able to adjust the particle grading, resulting in the overall material particle grading being either too coarse or too fine, and unable to be flexibly adjusted within the finished product particle distribution range, unable to meet the market requirements for cement water demand, setting time and strength. Summary of the invention

[0010] In order to solve the problems existing in the prior art, the present invention aims to propose a stationary blade for a self-sedimenting high-efficiency powder classifier, a design method and a high-efficiency powder classifier, which solves the problems of insufficient one-time powder selection capacity of the powder classifier, easy escape of coarse particles, inflexible control of coarse material fineness and severe wear of the stationary blades.

[0011] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0012] A stationary blade for a self-sedimenting high-efficiency powder classifier, the stationary blade being composed of a plurality of stationary blade units;

[0013] The stationary blade unit is divided into an inlet section, a middle section and an outlet section in sequence along the airflow direction, and the middle section includes a straight flow channel and at least one group of arc flow channels;

[0014] The inlet section is a trapezoidal flow channel whose width gradually decreases along the airflow direction. The inlet section, the straight flow channel 1, and the outlet section are connected in sequence to form a straight section of the airflow channel; the inlet of the straight flow channel 1 is connected to the inlet of the arc flow channel, and the outlet of the straight flow channel 1 is connected to the outlet of the arc flow channel. The airflow passing through the outlet of the arc flow channel is opposite to the airflow direction in the straight flow channel 1, so that the material in the airflow is settled.

[0015] Furthermore, the two sides of the trapezoidal flow channel are respectively arranged at a certain angle to the center line of the straight flow channel 1, and the angles are in the range of 0 to 50 degrees.

[0016] Furthermore, the arc flow channel includes a second direct flow channel and a circular arc flow channel, and the angle γ between the center line of the second direct flow channel and the center line of the first direct flow channel ranges from 10 to 60 degrees.

[0017] Furthermore, the value of γ is 30°.

[0018] Furthermore, the outlet section is a straight flow channel.

[0019] Furthermore, the number of the arc-shaped flow channels is two groups, and the two groups of arc-shaped flow channels are symmetrically arranged on both sides of the straight flow channel.

[0020] A design method for a stationary blade unit for a self-sedimenting high-efficiency powder classifier comprises the following steps:

[0021] 1) Calculate the powder selection air volume Q of the fan:

[0022] Q=1000000*P / Cs

[0023] Among them, Q represents the powder selection air volume of the fan, unit is m 3 / h; P represents the design capacity of the powder separator, in t / h; Cs represents the appropriate powder concentration for separating different materials, in g / m 3 ;

[0024] 2) The width B1 of the outlet end of the inlet section, the width B3 of the direct current channel 1 and the width B4 of the outlet section are equal. Calculate the width B1 of the outlet end of the inlet section:

[0025]

[0026] Among them, B1 represents the width of the outlet end of the inlet section, in mm; H represents the height of the classifier, in mm; n represents the number of static blade units; V represents the wind speed between static blades, in m / s;

[0027] 3) Calculate the width of DC channel 2 as B2:

[0028] B2=(1~5)*B1

[0029] Wherein, B2 represents the width of the second direct current channel, in mm;

[0030] 4) Calculate the rotor height-to-diameter ratio H / D R =0.4~0.5;

[0031] 5) Calculate the rotating diameter D of the moving blade R :

[0032]

[0033] Among them, D R Indicates the rotating diameter of the moving blade, in mm; V r Indicates rotor tangential, wind speed m / s;

[0034] 6) The effective height of the stationary blade unit is equal to the effective height of the moving blade. Calculate the effective height H of the moving blade:

[0035] H=D R *(H / D R )

[0036] Wherein, H represents the effective height of the moving blade, in mm;

[0037] 7) Determine that the length of the stationary blade unit ranges from 170 to 220 mm;

[0038] 8) Draw a stationary blade unit schematic diagram based on the calculated stationary blade unit structural parameters;

[0039] 9) Process the stationary blade unit according to the scheme drawing drawn in step 8).

[0040] Furthermore, in step 2), the wind speed V at the gap between the stationary blades is 12 to 18 m / s.

[0041] Furthermore, in step 3), when ultrafine products are sorted, B2=(1-5)*B1; when conventional fineness materials are sorted, B2=B1.

[0042] A high-efficiency powder classifier comprises a stationary blade as described in any of the above technical solutions, wherein a plurality of the stationary blade units are evenly distributed circumferentially on the periphery of a rotating cage formed by moving blades, and the upper and lower ends of each stationary blade unit are respectively fixed to the upper and lower ends of the outer shell of the powder classifier.

[0043] Compared with the prior art, the stationary blade for the self-settling high-efficiency powder classifier, the design method and the high-efficiency powder classifier described in the present invention have the following advantages:

[0044] (1) The inlet section of the stationary blade unit for the self-sedimentation high-efficiency powder classifier described in the present invention is a trapezoidal flow channel, which gradually decreases the width of the inlet section, gradually increases the wind speed at the inlet, and increases the probability of particle collision in the gas, thereby forming gradient sedimentation.

[0045] (2) The self-sedimenting high-efficiency powder classifier described in the present invention has an arc-shaped flow channel in the middle section of the static blade unit, which can divide the airflow carrying fine powder materials into two or three symmetrical airflows, which enter different airflow channels. After the side wall effect of the arc-shaped flow channel and the change of airflow direction, the fine powder particles in the airflow are further aggregated and settled, and the dust concentration in the airflow is further reduced; at the same time, the airflow at the outlet of the arc-shaped flow channel and the straight airflow channel flow in relative directions. After the airflow at the outlet of the arc-shaped flow channel merges with the straight airflow, the coarse particles in the airflow stall instantly, forming local vortices and convection, and the coarse particles gather and collide again, further settle and sink, and the dust concentration in the airflow is further reduced, thereby reducing the load of the moving blades for powder selection and improving the clarity of powder selection.

[0046] (3) The static blades for the self-sedimenting high-efficiency powder classifier described in the present invention can shorten the quality adjustment time of the finished product, adjust the material quantity and finished product quantity in the grinding equipment in real time, effectively control the yield rate, improve production efficiency and reduce production costs.

[0047] (4) The unit described in the present invention effectively improves the primary powder selection ability of the powder classifier, reduces the escape phenomenon of coarse particles, improves the flexibility of coarse material fineness control, and reduces the wear degree of the stationary blade unit; it is suitable for sorting ultrafine powder, can select qualified fine powder produced in the grinding process, and discharge coarse particles in time, reduce over-grinding of materials in the grinding equipment, save grinding power consumption, and is beneficial to energy conservation and emission reduction of production enterprises, improve production efficiency, and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0049] Figure 1 A structural diagram of a stationary blade unit provided in Embodiment 1 of the present invention;

[0050] Figure 2 A cross-sectional view of a stationary blade unit provided in Embodiment 1 of the present invention;

[0051] Figure 3 Schematic diagram of the length of the stationary blade unit provided in the first embodiment of the present invention

[0052] Figure 4 A schematic diagram of the airflow direction of a stationary blade unit provided in the first embodiment of the present invention;

[0053] Figure 5 A structural diagram of a stationary blade unit provided in Embodiment 2 of the present invention;

[0054] Figure 6 A schematic diagram of the airflow direction of a stationary blade unit provided in the second embodiment of the present invention;

[0055] Figure 7 This is a structural schematic diagram of a self-sedimentation high-efficiency powder classifier according to the first embodiment of the present invention;

[0056] Figure 8 This is a structural schematic diagram of a self-sedimentation high-efficiency powder classifier according to the second application example of the present invention;

[0057] Fig. 9 This is a front view of the structure of the self-sedimentation high-efficiency powder classifier of the present invention;

[0058] Fig.10 for Fig. 9 AA cross-sectional view of application embodiment 1;

[0059] Fig.11 for Fig. 9 AA cross-sectional view of application embodiment 2;

[0060] Fig.12 This is the relationship diagram between the Reynolds number Re and the pressure drop ratio Di for different types of stationary blades.

[0061] Description of reference numerals:

[0062] 1. Inlet section; 11. Straight plate 1; 12. Straight plate 2; 2. Middle section; 21. Straight channel 1; 22. Straight channel 2; 23. Circular arc flow channel; 3. Outlet section; 4. Stationary blades; 5. Moving blades; 6. Powder selection area; 7. Powder selector; 8. Coarse powder collecting cone. DETAILED DESCRIPTION

[0063] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0064] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0065] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0066] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0067] Embodiment 1

[0068] like Figures 1 to 4 As shown, a stationary blade for a self-sedimenting high-efficiency powder classifier, the stationary blade is composed of a plurality of stationary blade units;

[0069] The stationary blade unit is divided into an inlet section 1, a middle section 2 and an outlet section 3 in sequence along the airflow direction, wherein the middle section 2 includes a straight flow channel 21 and at least one group of arc-shaped flow channels;

[0070] The inlet section 1 is a trapezoidal flow channel whose width gradually decreases along the airflow direction. The inlet section 1, the direct current channel 21, and the outlet section 3 are connected in sequence to form a straight airflow channel; the inlet of the direct current channel 21 is connected to the inlet of the arc flow channel, and the outlet is connected to the outlet of the arc flow channel. The airflow passing through the outlet of the arc flow channel is opposite to the airflow direction in the direct current channel 21, so that the material in the airflow is settled.

[0071] In a preferred embodiment of the present invention, the two sides of the trapezoidal flow channel are respectively arranged at a certain angle to the center line of the direct current channel 21, and the angles are in the range of 0 to 50 degrees.

[0072] In actual use, the inlet section 1 is formed by a straight plate 11 and a straight plate 2 12 which are arranged at a certain angle to form a trapezoidal flow channel; the angle α between the straight plate 11 and the center line of the straight channel 1 21 ranges from 0 to 50°, and the angle β between the straight plate 2 12 and the center line of the straight channel 1 21 ranges from 0 to 50°.

[0073] In a preferred embodiment of the present invention, the arc flow channel includes a second direct current channel 22 and an arc flow channel 23, and an angle γ between a center line of the second direct current channel 22 and a center line of the first direct current channel 21 ranges from 10 to 60°.

[0074] In actual use, for sorting materials with different fineness requirements, the angle γ between the center line of the second straight channel 22 and the center line of the first straight channel 21 is required to be different; for grinding ultra-fine materials, it is necessary to increase the sorting capacity of the stationary blade unit, so it is necessary to increase the inclination angle γ to increase the sedimentation capacity of the middle section 2, and vice versa. In this embodiment, when the inclination angle γ is preferably 30°, the diversion effect is best when grinding cement and mineral powder.

[0075] In a preferred embodiment of the present invention, the outlet section 3 is a straight flow channel.

[0076] Working principle of the stationary blades of the self-sedimentation high-efficiency powder classifier:

[0077] The large end of the trapezoidal flow channel constitutes the inlet end of the fresh gas, and the small end is connected to the middle section 2 as the outlet end. The airflow carrying fine powder particles enters from the inlet end of the trapezoidal flow channel respectively. As the width of the trapezoidal flow channel gradually decreases, the wind speed gradient gradually increases, and the wind speed reaches the maximum at the outlet end of the trapezoidal flow channel. In this process, the gaps between the large particles in the gas gradually decrease, the collision probability increases, and the large particles gradually settle to form a primary settling area.

[0078] The gas that has been settled once in the trapezoidal flow channel enters the middle section 2, and the gas in the middle section 2 is divided into two airflows, one along the straight channel 21, and the other enters the arc flow channel. The direction of the airflow in the arc flow channel is constantly changing, and the fine powder materials in the gas are constantly colliding and impacting, forming a second sedimentation. At the confluence of the straight channel 21 and the arc flow channel, the airflow at the outlet of the arc flow channel forms a convective airflow in the opposite direction to the airflow in the straight channel 21. In this area, due to the convection of the gas, the gas flow rate drops rapidly, forming a vortex suspension, and the concentration of fine powder materials per unit area increases rapidly. Under the action of this convection and the rapid increase in concentration, the fine powder materials in the gas settle again.

[0079] There are fewer coarse particles in the gas at the outlet section 3. The airflow is accelerated over a certain distance in the outlet section and enters the moving blades for secondary powder selection.

[0080] Embodiment 2

[0081] like Figure 5 to Figure 6 As shown, there are two groups of arc-shaped flow channels, and the two groups of arc-shaped flow channels are symmetrically arranged on both sides of the direct current channel 21.

[0082] In actual use, the inlets of the two sets of arc flow channels are connected to the inlet of the straight flow channel 21, and the outlets are connected to the outlet of the straight flow channel 21. The airflow carrying fine powder enters from the inlet section 1, and after a sedimentation in the inlet section 1, the middle section 2 divides the airflow into three streams. The airflow carrying fine powder particles changes the direction of the airflow while passing through the two sets of arc flow channels. At the same time, the coarse particles in the gas in the side wall area can also be settled and sink under the side wall effect of the arc flow channel.

[0083] The airflows of the two sets of arc-shaped flow channels converge at the outlet and the outlet of the straight channel 21, forming a large-scale vortex. Since the two sets of arc-shaped flow channels are symmetrically designed, the airflow in the vortex area can convect more evenly, thereby achieving collision and collision in a larger area, so that a larger proportion of large particles accumulate, settle and sink to the coarse powder collection device of the powder classifier, further reducing the proportion of dust particles in the gas, so that the concentration of fine powder entering the moving blades is reduced. When the rotating speed of the moving blades remains unchanged, finer particle sizes can be selected to obtain finished products with ultra-fine specific surface area and fineness, and at the same time, the powder selection efficiency and powder selection clarity of the powder classifier can be improved.

[0084] Embodiment 3

[0085] A design method for a stationary blade unit for a self-sedimenting high-efficiency powder classifier comprises the following steps:

[0086] 1) Calculate the powder selection air volume Q of the fan:

[0087] Q=1000000*P / Cs

[0088] Among them, Q represents the powder selection air volume of the fan, unit is m 3 / h; P represents the design capacity of the powder separator, in t / h; Cs represents the appropriate powder concentration for separating different materials, in g / m 3 ;

[0089] The material is cement raw material, and the powder concentration Cs is 600g / m 3 , rotor radial wind speed Vr=4.0±0.5m / s;

[0090] The materials are coal and cement, and the powder concentration Cs is 450g / m 3;Rotor radial wind speed Vr=3.5±0.5m / s;

[0091] The material is slag, and the powder concentration Cs is 350g / m 3 ; Rotor radial wind speed Vr = 3±0.5m / s.

[0092] 2) The width B1 of the outlet end of the inlet section, the width B3 of the direct current channel 1 and the width B4 of the outlet section are equal. Calculate the width B1 of the outlet end of the inlet section:

[0093]

[0094] Among them, B1 represents the width of the outlet end of the inlet section, in mm; H represents the height of the powder classifier, in mm; n represents the number of static blade units; V represents the wind speed between the static blades, in m / s, preferably, V is 12-18 m / s. In actual use, the outlet end of the inlet section 1, the straight flow channel 21 and the outlet section 3 are connected in sequence to form a straight section airflow channel, and the three have the same width, which reduces the resistance of airflow, optimizes the movement trajectory of particles in the airflow, makes it easier for particles to settle at the confluence of the straight flow channel 21 and the arc flow channel, and improves the sorting effect of the powder classifier.

[0095] 3) Calculate the width of DC channel 2 as B2:

[0096] B2=(1~5)*B1

[0097] Among them, B2 represents the width of the direct current channel 22, in mm; in actual use, B2≥B1; if ultra-fine products are sorted, the inlet section 1 needs to reduce the wind speed and multiple sedimentation, the width B2=(1~5)*B1; for conventional fineness materials, such as raw meal, coal powder, cement and other traditional materials, B2=B1.

[0098] 4) Calculate the rotor height-to-diameter ratio H / D R =0.4~0.5;

[0099] 5) Calculate the rotating diameter D of the moving blade R :

[0100]

[0101] Among them, D R Indicates the rotating diameter of the moving blade, in mm; V r Indicates rotor tangential, wind speed m / s;

[0102] 6) The effective height of the stationary blade unit is equal to the effective height of the moving blade. Calculate the effective height H of the moving blade:

[0103] H=D R *(H / D R )

[0104] Wherein, H represents the effective height of the moving blade, in mm;

[0105] 7) Determine the length of the stationary blade unit as L, and the value range of L is 170 to 220 mm;

[0106] The length of the outlet section is L1, the radius of the outer wall of the arc flow channel is R, the length of the straight channel 22 is L2, and the length of the inlet section close to the two sides of the straight channel is L3; according to the materials of different fineness, the flow field simulation is carried out to calculate the optimal L1, L2, L3, and R values, as shown in Table 1.

[0107] 8) Draw a stationary blade unit schematic diagram based on the calculated stationary blade unit structural parameters;

[0108] 9) Process the stationary blade unit according to the scheme drawing drawn in step 8).

[0109] Table 1 The range of L1, L2, L3 and R for materials with different fineness

[0110] materials L1(mm) L2(mm) L3(mm) R(mm) Raw Materials 10～30 30～60 50～80 10～30 fuel 15～30 30～60 60～90 10～30 cement 20～40 20～50 60～80 30～50

[0111] Embodiment 4

[0112] like Figures 7 to 11 As shown, a high-efficiency powder classifier includes the stationary blades provided in Example 1 or Example 2, and multiple stationary blade units are evenly distributed in a circle around the periphery of the rotating cage formed by the moving blades, and the upper and lower ends of each stationary blade unit are respectively fixed to the upper and lower ends of the outer shell of the powder classifier.

[0113] The technical effect of the stator blade of the present invention applied to the self-settling stator blade powder separator is mainly reflected in the reduction of the speed of the powder separator moving blade, high powder separation efficiency, high separation clarity, etc. The specific technical effects are as follows:

[0114] 1) Compared with the traditional straight-blade static blade classifier, the classifier speed is reduced by 25-30%, the classifier efficiency is increased by 8-10%, the bypass value β≤5%, the main engine power consumption is reduced by 12.4%, the finished product ratio is increased by 15%-20%, and the finished product particle distribution n value is reduced by 7%-8%.

[0115] 2) Compared with the LV type stationary blade powder classifier, the system output is increased by 20%, the finished product specific surface area is increased by 8% to 10%, the finished product particle distribution n value is reduced by 6% to 7%, and the system power consumption is reduced by 10% to 12.5% ​​(reduction ≥ 2kWh / t).

[0116] 3) By adjusting the angle of the arc flow channel, the gas split flow ratio can be adjusted to adjust the size and ratio of the particles that the static blades collide with, thereby achieving the powder selection efficiency of particles of different particle sizes and effectively controlling the particle size distribution of the finished product. It has the powder selection ability to meet the requirements of different finished product particle size grading, and is very suitable for cement, slag and other material grinding systems with high requirements for finished product quality.

[0117] Working principle of self-sedimentation high-efficiency powder separator:

[0118] The material ground by the roller is thrown out by the grinding disc under the action of centrifugal force and falls to the wind ring outside the circumference of the grinding disc. The hot air from the wind ring is carried to the powder classifier for powder selection. The gas carrying the material flows through the stationary blades provided in the first or second embodiment for primary sorting, and the coarser particles in the gas are selected by sedimentation, thereby reducing the proportion of coarse particles in the gas.

[0119] The coarse particles are collected by the coarse powder collecting cone 8 and returned to the grinding disc for re-grinding, and then carry the remaining fine particles into the powder selection area 6 between the moving blades and the stationary blades. The airflow entering the powder selection area rotates with the rotor under the dual effects of the rotor moving blades and the stationary blades, and flows through the rotor moving blades at the same time, and finally leaves the powder classifier through the inside of the rotor and the finished product outlet of the powder classifier, and enters the finished product collection device. The shape of the moving blades and the spacing setting of the powder selection area belong to the existing technology.

[0120] The finite element software COMSOL Multiphysics and Fluent software were used to simulate the flow field of the static blade structure of the self-sedimentation powder separator to find out the relationship between the Reynolds number Re and the pressure drop ratio Di. The specific analysis results are shown in Fig.12 As shown in Table 2, it can be seen that: with the increase of Reynolds number Re, the pressure drop ratio Di of single arc flow channel and symmetrical arc flow channel increases; for the same Reynolds number Re, the Di value of symmetrical arc flow channel is much larger than that of single arc flow channel. In other words, the higher the symmetry, the greater the pressure drop ratio. Therefore, the symmetrical arc flow channel has better sedimentation and sorting ability. Under the premise of a suitable pressure drop ratio Di, a symmetrical self-sedimentation powder separator with better static sorting ability can be selected.

[0121] In order to verify the actual effect of the self-settling static blade high-efficiency powder classifier, a semi-industrial test was carried out in the laboratory using a cement vertical mill TRMK5.6. The powder classifiers with different static blade shapes were compared under basically the same working conditions. The specific results are shown in Table 3.

[0122] The 45μm, 80μm and 200μm sieve residues of the powder selectors with different static blades on the market were measured, and the powder selection efficiency of the powder selectors was calculated. The results are shown in Table 3 below: It can be seen from the table that the powder selection efficiency of the self-settling static blades can reach 75-78%, which is about 10-15% higher than that of the traditional static blades; at the same time, the self-settling static blades are conducive to reducing the resistance of the vertical roller mill, and the running resistance of the mill can be reduced to 6000-6500Pa, a reduction of about 25%. And the thickness of the windward side is thicker, which can increase the service life of the blades; due to the improvement of the primary sorting capacity, the particle size of the material entering the gap between the dynamic and static blades is relatively uniform, which indirectly improves the clarity of the secondary sorting of the dynamic blades, so that the fineness n value of the finished product reaches below 0.9, the particle grading is more concentrated, and the content of particles below 3μm is increased. For pulverized coal, the pulverized coal can be finer, which is conducive to the calcination of the clinker burning system and improves the burnout rate of pulverized coal.

[0123] Table 2 Comparison of Di values ​​of Example 1 and Example 2

[0124]

[0125]

[0126] Table 3 Efficiency determination of powder selectors with different fineness and different stationary blade forms

[0127]

[0128] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A stationary blade for a self-sedimenting high-efficiency powder classifier, the stationary blade being composed of a plurality of stationary blade units, characterized in that: The stationary blade unit is divided into an inlet section, a middle section and an outlet section in sequence along the airflow direction, and the middle section includes a straight flow channel and at least one group of arc flow channels; The inlet section is a trapezoidal flow channel whose width gradually decreases along the airflow direction. The inlet section, the straight flow channel 1, and the outlet section are connected in sequence to form a straight section of the airflow channel; the inlet of the straight flow channel 1 is connected to the inlet of the arc flow channel, and the outlet of the straight flow channel 1 is connected to the outlet of the arc flow channel. The airflow passing through the outlet of the arc flow channel is opposite to the airflow direction in the straight flow channel 1, so that the material in the airflow is settled.

2. The stationary blade for a self-sedimenting high-efficiency powder separator according to claim 1 is characterized in that: The two sides of the trapezoidal flow channel are respectively arranged at a certain angle to the center line of the straight flow channel 1, and the angles are in the range of 0 to 50 degrees.

3. The stationary blade for a self-sedimenting high-efficiency powder separator according to claim 1 is characterized in that: The arc flow channel includes a second direct flow channel and a circular arc flow channel, and the angle γ between the center line of the second direct flow channel and the center line of the first direct flow channel ranges from 10° to 60°.

4. The stationary blade for a self-sedimenting high-efficiency powder separator according to claim 3 is characterized in that: The value of γ is 30°.

5. The stationary blade for a self-sedimenting high-efficiency powder separator according to claim 1 is characterized in that: The outlet section is a straight flow channel.

6. The stationary blade for a self-sedimenting high-efficiency powder separator according to claim 1 is characterized in that: The number of the arc-shaped flow channels is two groups, and the two groups of arc-shaped flow channels are symmetrically arranged on both sides of the straight flow channel.

7. A design method for a stationary blade unit for a self-sedimenting high-efficiency powder classifier, wherein a plurality of stationary blade units constitute the stationary blade for a self-sedimenting high-efficiency powder classifier according to any one of claims 1 to 6, characterized in that: The steps include: 1) Calculate the powder selection air volume Q of the fan: Q=1000000*P / Cs Among them, Q represents the powder selection air volume of the fan, unit is m 3 / h; P represents the design capacity of the powder separator, in t / h; Cs represents the appropriate powder concentration for separating different materials, in g / m 3 ; 2) The width B1 of the outlet end of the inlet section, the width B3 of the direct current channel 1 and the width B4 of the outlet section are equal. Calculate the width B1 of the outlet end of the inlet section: Among them, B1 represents the width of the outlet end of the inlet section, in mm; H represents the height of the classifier, in mm; n represents the number of static blade units; V represents the wind speed between static blades, in m / s; 3) Calculate the width of DC channel 2 as B2: B2=(1~5)*B1 Wherein, B2 represents the width of the second direct current channel, in mm; 4) Calculate the rotor height-to-diameter ratio H / D R =0.4~0.5; 5) Calculate the rotating diameter D of the moving blade R : Among them, D R Indicates the rotating diameter of the moving blade, in mm; V r Indicates rotor tangential, wind speed m / s; 6) The effective height of the stationary blade unit is equal to the effective height of the moving blade. Calculate the effective height H of the moving blade: H=D R *(H / D R ) Wherein, H represents the effective height of the moving blade, in mm; 7) Determine the length L of the stationary blade unit, where L ranges from 170 to 220 mm; 8) Draw a stationary blade unit schematic diagram based on the calculated stationary blade unit structural parameters; 9) Process the stationary blade unit according to the scheme drawing drawn in step 8).

8. The design method of stationary blades for a self-sedimenting high-efficiency powder separator according to claim 7, characterized in that: In step 2), the wind speed V at the gap between the stationary blades is 12 to 18 m / s.

9. The design method of stationary blades for a self-sedimenting high-efficiency powder separator according to claim 7, characterized in that: In step 3), when ultrafine products are sorted, B2 = (1-5) * B1; when conventional fineness materials are sorted, B2 = B1.

10. A high-efficiency powder classifier, characterized by: It comprises the stationary blade as claimed in any one of the preceding claims, wherein a plurality of the stationary blade units are evenly distributed circumferentially on the periphery of the rotating cage formed by the moving blades, and the upper and lower ends of each stationary blade unit are respectively fixed to the upper and lower ends of the outer shell of the powder classifier.

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