Efficient powder selecting device of vertical mill

Abstract

The invention relates to the technical field of powder classification, in particular to an efficient powder selecting device of a vertical mill, which comprises an integral powder selecting mechanism consisting of a rotor blade, a static blade, a labyrinth, a straight-opening labyrinth, a felt seal, a sealing fan pipeline and the like. The rotor blades are designed to be bent, the cutting-in speed of dust particles can be greatly reduced, natural sedimentation of large particles is facilitated, meanwhile, the rotor blades are also designed to be bent, the cutting-in speed when dust enters can be reduced through the bent positions (sedimentation areas), secondary sedimentation of the large particles is facilitated, the rotating speed of the rotor can be reduced, and the separation efficiency can be improved; and meanwhile, excessive abrasion of parts caused by high-speed washing can be reduced. According to the scheme, through the ingenious design of the bent blades and the optimized sealing design, the rotating speed needed by powder selection can be greatly reduced, the grading efficiency is improved, the service life of a rotor part is prolonged, and finally the application effects of low rotating speed, high efficiency and low abrasion of the powder selection device are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of powder classification, in particular to a vertical mill high-efficiency powder selection device. Prior art

[0002] Vertical mill equipment and technology originated in Germany in the 1920s. Its wide application, economy and stability have been proven by industrial practice. It is one of the preferred energy-saving equipment in today's grinding field.

[0003] my country initially introduced vertical mills, which were mainly used for grinding cement raw materials, raw coal, gypsum and other materials in the cement industry. Due to its advantages of high production and low consumption, it has gradually replaced the position of ball mills in the cement industry. The requirements for powder making in the cement industry are usually relatively extensive, and generally the 80-micron sieve residue can be controlled within 12%. In order to take advantage of the energy-saving and scale advantages of vertical mills, most of the raw material preparation in the domestic glass fiber industry also adopts vertical mill powder making. However, in the actual production process, the problem of excessive wear of the blades of the vertical mill separator leads to the disadvantages of low production, high consumption and high maintenance rate of the mill, which has always been one of the main problems faced by major glass fiber companies.

[0004] The reason is that although the glass fiber industry has adopted vertical mills with high grinding efficiency, its powder selection device still uses the technology of the cement industry, without any innovative technological breakthroughs. When producing talc powder or white blister powder, the raw materials of glass fiber, the static blades of the powder selector cannot effectively screen the coarse particles, resulting in a very high rotor speed of the powder selector. Talc powder or white blister powder is a high-silicon and high-aluminum material, and only a high speed can achieve the product fineness, resulting in serious wind sweeping and erosion of the blades and a short service life. The final result is low powder selection efficiency, large internal circulation volume of the mill, and serious over-grinding, making it difficult to achieve the goal of high production and low consumption of the mill.

[0005] In order to reduce the problems of large wear of powder classifier blades, high circulation load in the mill and serious over-grinding, the present invention designs a high-efficiency powder classifier in the form of arc-shaped blades. Combined with the optimized powder classifier space and sealing design, the application effect of low speed, high efficiency and low wear of the powder classifier can be achieved.

[0006] The present invention is achieved through the following technical solutions:

[0007] (1) The original powder selection machine rotor blades adopt a straight plate design, and the blades are evenly arranged at a certain oblique angle. In order to achieve high-fine separation, the number of blades is large and dense; the stationary blades also adopt a straight plate design, with a larger length and width, which plays a role in pre-separating large particles, and the number is small. The present invention adopts a curved arc design for both the rotor blades and the stationary blades. The powder-containing airflow enters the bent stationary blades in a suction-type manner, rather than a fan-type entry like the straight blades. After the airflow enters, the cross-sectional area of ​​the bend (sedimentation zone) is larger, which can greatly reduce the cutting-in speed of the dust particles, which is conducive to the natural sedimentation of large particles, making the effective dust concentration entering the rotor powder selection zone higher, providing better conditions for the high-fine separation of the rotor. At the same time, the rotor blades are also bent. The bend (sedimentation zone) can reduce the cutting-in speed of the dust when it enters, which is conducive to the secondary sedimentation of large particles, which can both reduce the rotor speed and improve the separation efficiency.

[0008] (2) Due to the high fineness requirements of pyrophyllite powder or white blister powder in the glass fiber industry, usually the 325 mesh sieve has a residue of less than 0.5% and the 100 mesh sieve has a full pass, that is, there must not be any large particles, otherwise it will cause problems such as wire breakage and uneven wire drawing in the downstream kiln. In order to control the escape of large particles, the present invention designs a three-labyrinth sealing form, which provides layer-by-layer protection, and with an external sealing fan as the final barrier, there is almost no problem of large particles running out and contaminating the finished product during production;

[0009] (3) The optimized powder selection space and sealing design make the effective dust concentration entering the powder selection area higher, which is beneficial to the rotor to separate the product. The rotor speed can be greatly reduced to about half of the original speed, thereby reducing the erosion and wear of the blades by dust, greatly extending their service life and reducing the frequency of maintenance and replacement.

[0010] After the above steps, the beneficial effects of the present invention are: the rotor speed of the vertical grinding and selection device is reduced by 50% to 60%, the pressure loss of the mill is reduced by 15% to 20% (resistance is reduced), the life of the rotor blades is increased by 50% to 60%, and the output of the mill is increased by 15% to 20% year-on-year. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0012] Figure 1 It is a schematic diagram of the planar structure of the powder selection device of the present invention.

[0013] Figure 2 It is a cross-sectional view (maze design diagram) of the device of the present invention.

[0014] In the figure: 1-rotor blade (bent), 2-stationary blade (bent), 3-maze, 4-straight maze, 5-felt seal, 6-sealed fan duct. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings.

[0016] See attached Figure 1 As shown in the figure, when the vertical mill is grinding materials, the powder in the mill will be carried by the airflow to the powder selection device at the top of the mill for coarse and fine separation. The dust-containing material flow enters in the direction of Figure 1 As shown in the direction of the black arrow, the bend (sedimentation zone) of the static blade 2 has a larger cross-sectional area, which will greatly reduce the cutting speed of the dust particles. Due to their own weight, most of the larger particles will naturally settle into the grinding disc and re-enter a new grinding cycle, thereby achieving a preliminary screening effect, making the effective dust concentration (the finished product rate in the dust) entering the rotor blade 1 area higher, which is more conducive to the efficient separation of the finished product and the reduction of the speed of the rotor blade 1 (high concentration and low speed can complete the classification); at the same time, the rotor blade 1 also adopts a bending design, and the curvature of the bend (sedimentation zone) reduces the cutting speed of the dust flow when it enters, further blocking the large particles in the airflow, allowing them to settle into the mill hopper and enter a new grinding cycle, thereby reducing the mill pressure loss and system resistance, reducing the operating load of the rear exhaust fan, and achieving the purpose of increasing production and reducing consumption. Since the speed of the powder selection device rotor is reduced by half or more than the original design, the wear and tear of the dust on it will be greatly reduced, thereby extending the service life of the rotor.

[0017] The main essence of this invention lies in the bending angle and number of the stationary blades, the bending angle and number of the rotor blades, and the gap design in the powder selection area between the rotor blades and the stationary blades. For the sorting requirements of different finenesses, a reasonable powder selection device shell space design is matched to guide the dust-laden airflow into the powder selection device at a suitable speed, thereby achieving the purpose of efficient separation and reducing wear.

[0018] See attached Figure 2 As shown in the figure, the labyrinth design of the rotating part (rotor blades) and the stationary part (stationary blades) is displayed. The dusty powder is blown by the airflow into the gap between the rotor blades and the stationary blades in the powder selection area, first passing through the barrier of the labyrinth 3, then passing through the barrier of the straight-mouth labyrinth 4 (this part must be finely processed), and finally passing through the barrier of the felt seal 5. With the external sealed fan duct 6 as the final barrier, there is basically no problem of large particles escaping and causing pollution to the product. Daily maintenance only requires necessary replacement according to the wear of the felt seal to ensure the long-term stable and efficient operation of the powder selection device.

Claims

1. A vertical mill high-efficiency powder selection device, characterized by: The device comprises rotor blades, stationary blades and a sealing structure. The rotor blades and stationary blades are of a bent design rather than a conventional straight plate design; The structure adopts a four-sealing design, which includes a sealed fan duct, a wool felt seal, a labyrinth, and a straight-mouth labyrinth.

2. A vertical mill high-efficiency powder selection device according to claim 1, characterized in that: The stationary blades are bent at a certain angle, and are designed to be bent outward and straight inward when viewed from the direction in which the dust airflow enters; the rotor blades are also bent at a certain angle, and are designed to be straight outward and bent inward when viewed from the direction in which the dust airflow enters.

3. A vertical mill high-efficiency powder selection device according to claim 1, characterized in that: The sealing structure is a sealing design of a mechanical seal plus an external sealing fan.

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