Medium speed coal mill impeller arrangement

Abstract

The invention discloses a medium-speed coal mill impeller device, and relates to a coal mill impeller device. The medium-speed coal mill impeller device comprises a moving ring device and a static ring device. The moving ring device comprises moving ring blocks. The moving ring blocks are assembled in a circumferential direction. A guide port is arranged in the moving ring blocks and penetrates the moving ring blocks. The guide port is an outwardly-inverted asymmetric hyperbolic structure in a longitudinal section. A guide vane is arranged in the guide port and is in a spiral shape. The static ring device comprises static ring blocks. The static ring blocks are provided with a guide angle β. The static ring blocks are assembled in a circumferential direction. The upper surfaces of the circumferentially-assembled static ring blocks are in an inverted conical frustum structure. The static ring device is located above the moving ring device. The static ring blocks are adjacent to the upper sides of the guide ports. The impeller device can ensure the original wind and powder guiding effect, and can omit the original three sets of guiding devices of the medium-speed coal mill, so that the wear of the original guiding devices can be avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of coal mill impeller device. BACKGROUND

[0002] The existing HP type medium-speed coal mill impeller device is as shown in Figures 1-2 The primary air of medium-speed coal mill enters the impeller device from B, repeatedly blows the ground coal powder to the guide device (liner), changes the flow direction of coal powder gas stream by the guide device (liner), and the guide device (liner) can only be arranged in three groups along the circumferential direction of the mill chamber due to the interference of the fixed position of the three grinding rollers in the mill chamber, and has a guiding effect on the local coal powder in the mill chamber. The existing HP type medium-speed coal mill impeller device includes a guide device (liner), an impeller device, a grinding bowl, an extension ring, and a separator body at the grinding roller position, and the inclination angle of the separator body at the grinding roller position is α. Since the blades of the impeller device that changes the wind direction are straight plate solid structures, the hot primary air is blown in from B, so the coal powder falling into the impeller is always blown directly in one direction, and there is a phenomenon that a part of the hot air does not pass through the impeller adjustment and directly enters the grinding area to mix with the coal powder. There is also a part of the wind powder that is directly blown to the guide device (liner), changes the flow direction by the guide device (liner), and falls into the impeller device again, so the work is repeated, which leads to low powder output rate of the coal mill, and serious wear of the impeller device and the guide device (liner).

[0003] However, due to the forced turning of the coal powder gas stream through the guide device (liner), the coal powder gas stream continuously and uninterruptedly impacts the guide device (liner), causing serious wear of the guide device (liner), and further causing short service life of the guide device (liner), high cost of spare parts and maintenance and repair, and low efficiency of the coal mill. SUMMARY

[0004] In order to solve the problems of serious wear of the guide device (liner), short service life, high cost of spare parts and maintenance and repair, and low efficiency of the coal mill, the present application provides a medium-speed coal mill impeller device.

[0005] The medium-speed coal mill impeller device of the present application includes a moving ring device and a stationary ring device.

[0006] The moving ring device includes a moving ring block, and the moving ring block is assembled along the circumference of the extension ring. The moving ring block is provided with a guide port penetrating through the moving ring block, and the longitudinal section of the guide port is an outwardly turned asymmetric hyperbolic structure. The guide port is provided with a guide vane, and the guide vane is in a spiral shape.

[0007] The stationary ring device includes a stationary ring block, and the stationary ring block is provided with a guide angle β. The stationary ring block is assembled in a circumferential direction, and the upper surface of the circumferentially assembled stationary ring block is in an inverted conical frustum structure.

[0008] The stationary ring device is located above the moving ring device, and the stationary ring block is adjacent to the upper side of the guide port.

[0009] Further, the guide vane 1-4 is a longitudinal spiral, and the spiral angle is 10°-25° or 25°-80°. When grinding lean coal and anthracite, the guide vane 1-4 with the spiral angle of 10°-25° is selected; when grinding bituminous coal and lignite, the guide vane 1-4 with the spiral angle of 25°-80° is selected.

[0010] Further, the moving ring block 1-2 is connected to the vertical axis of the mill bowl 2 by the extension ring 3 through mechanical bolts.

[0011] Further, the static ring block 1-6 is provided with a support ring 1-7 between the inner wall of the medium-speed coal mill; the upper surface of the static ring block 1-6 intersects with the upper surface of the support ring 1-7; the included angle between the upper surface of the support ring 1-7 and the inner wall of the medium-speed coal mill above is γ, which is the same as the inclination angle α of the separator body 5 at the mill roller; the support ring 1-7 is fixedly connected with the static ring block 1-6 and the inner wall of the medium-speed coal mill, respectively.

[0012] Further, the guide angle β of the static ring block 1-6 is ≥20°.

[0013] Further, the longitudinal section axis of the guide port 1-3 points to the center axis of the impeller from bottom to top, and the included angle between the outlet of the guide port 1-3 and the horizontal plane is ≥20°.

[0014] Further, the included angle between the outlet of the guide port 1-3 and the horizontal plane is the same as the guide angle β of the static ring block 1-6.

[0015] Further, the inlet-to-outlet area ratio of the guide port 1-3 is 1.3-5:1, which can appropriately increase the wind speed.

[0016] Further, the moving ring block 1-2 and the guide vane 1-4 are an integral structure.

[0017] Further, the moving ring device 1-1 includes a plurality of moving ring blocks 1-2 of the same specification.

[0018] Further, the moving ring block 1-2 and the extension ring 3 are an integral structure.

[0019] Further, the static ring device further includes a stepped surface 1-8, which is fixedly connected with the inner wall of the medium-speed coal mill below the static ring block 1-6 and the support ring 1-7. The stepped surface can position the static ring block. As shown in Figs. 5 and Figure 6 The setting of the lower swing angle δ in the figure can increase the angle of the air inlet guide port of the moving ring device, realize a larger inlet-to-outlet area ratio of the guide port 1-3, and thus increase the air inlet amount and improve the wind speed.

[0020] The primary air after mixing cold and hot air enters from B, and the air passes through the guide port 1-3 on the dynamic ring block 1-2, and forms the guide air rotating upward under the action of the rotating centrifugal force of the dynamic ring device 1-1 and the guide vane 1-4. The impeller device combined by the dynamic ring device 1-1 and the static ring device 1-5 can effectively guide the air and powder, and realize the high-efficiency conveying and separation of the air and powder of the medium-speed coal mill, by means of the guide angle β of the static ring block 1-6 being not less than 20°. The primary air is sprayed out through the guide port with the structure of the outwardly turned asymmetric hyperbola, and not only the air speed is improved, but also the air direction is changed, the airflow (primary air) changes from a straight line to an area, and the diffusion area is formed under the action of the guide vane in the guide port, and the air and powder concentration in the diffusion area is uniform, and the coal powder is not easy to deposit. The static ring block extends the bowl height of the mill bowl, so that the primary air is more concentrated in the diffusion area; the support ring arranged outside the static ring block forms a backflow area, and the coal powder descending again is sent into the diffusion area, and the airflow in the backflow area also hinders the impact of the coal powder in the diffusion area on the separator.

[0021] The impeller device of the application can ensure the original air and powder guiding effect, and omit the original three sets of guiding devices (liners) of the medium-speed coal mill, so that the wear of the original guiding devices (liners) is avoided. Moreover, the impeller device is arranged continuously in the circumferential direction, the guiding effect is better, the conveying and separation effects are stronger, and energy saving and high efficiency are achieved.

[0022] The impeller device of the application has the following characteristics: 1) the impeller device has simple structure, convenient installation, optimization, energy saving, high efficiency, reduced wear and reduced material loss;

[0023] 2) the guiding structure of the dynamic ring block 1-2 and the inclined guiding structure on the upper end surface of the static ring device in the impeller device of the application jointly guide the flow direction of the coal powder, the structure is reasonable, the original guiding devices (liners) of the medium-speed coal mill can be replaced, the wear of the guiding devices (liners) does not exist, material is saved, loss is reduced, and installation and maintenance are more convenient;

[0024] 3) the longitudinal section of the guide port 1-3 in the impeller device of the application adopts the structure of the outwardly turned asymmetric hyperbola, the guide vane uniformly distributed in the guide port and the spiral shape of the guide vane 1-4 jointly produce effective guiding effect on the primary air, and the coal powder is optimally guided;

[0025] 4) the upper surface of the static ring block 1-6 after being assembled in the circumferential direction is in the structure of the inverted conical frustum, and the coal powder is guided to the center;

[0026] 5) The angle between the upper surface of the support ring 1-7 and the inner wall of the medium-speed coal mill above it in the impeller device of the application is γ, which is the same as the angle α of the inclination of the separator body 5 at the grinding roller, so that the static ring device and the inner cylinder wall of the coal mill have a uniform guide angle in the circumferential direction, facilitating production and processing;

[0027] 6) The impeller device of the application has two structural modes. One is a split structure for the dynamic ring device, which needs to be used in cooperation with the extended ring of the equipment; the other is an integrated structure, which is formed integrally with the extended ring and the dynamic ring block, and can be directly assembled on the grinding bowl. The dynamic ring device with a split structure can be assembled by multiple dynamic ring blocks 1-2 of the same specification, which has interchangeability in maintenance and installation; similarly, the static ring device 1-5 can also be assembled by multiple static ring blocks 1-6 of the same specification, which also has interchangeability in maintenance and installation. The dynamic ring device with an integrated structure can reduce the assembly surface, make installation more convenient, and increase the bearing capacity of the dynamic ring device while exerting all the functions of the dynamic ring device. The dynamic ring device is designed in two structures, which can be flexibly selected according to the requirements of the transformation. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a top view and a sectional view of the impeller device of the existing HP medium-speed coal mill;

[0029] Figure 2 is an A-A sectional view of the impeller device of the existing HP medium-speed coal mill;

[0030] Figure 3 is a top view of the impeller device of the medium-speed coal mill of the application;

[0031] Figure 4 is a C-C sectional view of the impeller device of the medium-speed coal mill of the application;

[0032] Figure 5 is a local enlarged view of the structure at position I of the impeller device of the medium-speed coal mill of the application (the dynamic ring device is a split structure);

[0033] Figure 6 is a local enlarged view of the structure at position I of the impeller device of the medium-speed coal mill of the application (the dynamic ring device is an integrated structure);

[0034] In the drawings, 1-1 is a dynamic ring device, 1-2 is a dynamic ring block, 1-3 is a guide port, 1-4 is a guide vane, 1-5 is a static ring device, 1-6 is a static ring block, 1-7 is a support ring, 2 is a grinding bowl, 3 is an extended ring, 5 is a separator body at the grinding roller, 6 is a guide device (liner), 1-8 is a step surface, and δ is a lower swing angle. DETAILED DESCRIPTION

[0035] 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.

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0037] Specific implementation method one: Combining Figures 3-5 This embodiment describes the high-speed coal mill impeller device, which includes a dynamic ring device 1-1 and a stationary ring device 1-5.

[0038] The moving ring device 1-1 includes a moving ring block 1-2; the moving ring block 1-2 is assembled circumferentially along the extension ring 3; the moving ring block 1-2 is provided with a guide port 1-3 that penetrates the moving ring block, and the longitudinal section of the guide port 1-3 is an outward-turned asymmetrical hyperbolic structure; the guide port 1-3 is provided with a guide vane 1-4, and the guide vane 1-4 is spiral-shaped.

[0039] The stationary ring device 1-5 includes a stationary ring block 1-6, which has a guide angle β. The stationary ring block 1-6 is circumferentially assembled, and its upper surface has an inverted frustum-shaped structure. The stationary ring device 1-5 is located above the moving ring device 1-1, and the stationary ring block 1-6 is adjacent to the upper edge of the outer side of the guide port 1-3. The guide vanes 1-4 are evenly arranged inside the guide port 1-3. The guide vanes 1-4 are longitudinally spiral. When grinding lean coal and anthracite, guide vanes 1-4 with a spiral angle of 10°~25° are selected; when grinding bituminous coal and lignite, guide vanes 1-4 with a spiral angle of 25°~80° are selected. The moving ring block 1-2 is mechanically bolted to the grinding bowl 2 in the vertical axis through an extension ring 3. The stationary ring block 1-5 A support ring 1-7 is provided between the stationary ring block 1-6 and the inner wall of the medium-speed coal mill; the upper surface of the stationary ring block 1-6 intersects with the upper surface of the support ring 1-7; the angle between the upper surface of the support ring 1-7 and the inner wall of the medium-speed coal mill is γ, which is the same as the angle α of the inclination of the separator body 5 at the grinding roller; the support ring 1-7 is fixedly connected to the stationary ring block 1-6 and the inner wall of the medium-speed coal mill respectively; the guide angle β of the stationary ring block 1-6 is ≥20°; the longitudinal axis of the guide port 1-3 points from bottom to top to the impeller center axis; the inlet and outlet area ratio of the guide port 1-3 is 1.3~5:1; the moving ring block 1-2 and the guide vane 1-4 are an integral structure; the moving ring device 1-1 includes multiple moving ring blocks 1-2 of the same specification.

[0040] Specific Implementation Method Two: Combining Figure 3 , Figure 4 and Figure 6The embodiment is illustrated, and the medium-speed coal mill impeller device in the embodiment comprises a moving ring device 1-1 and a static ring device 1-5;

[0041] The moving ring device 1-1 comprises a moving ring block 1-2; the moving ring block 1-2 is assembled in the circumferential direction along the extension ring 3; the moving ring block 1-2 is provided with a guide port 1-3 penetrating through the moving ring block, the guide port 1-3 has an everted asymmetric hyperbolic structure in the longitudinal section; the guide port 1-3 is provided with a guide vane 1-4, and the guide vane 1-4 is in a spiral shape;

[0042] The static ring device 1-5 comprises a static ring block 1-6, the static ring block 1-6 is provided with a guide angle β, the static ring block 1-6 is assembled in the circumferential direction, and the upper surface of the circumferentially assembled static ring block 1-6 has an inverted truncated cone structure; the static ring device 1-5 is located above the moving ring device 1-1, the static ring block 1-6 is adjacent to the upper side of the guide port 1-3 outside; the guide vanes 1-4 are uniformly arranged in the guide port 1-3; the guide vanes 1-4 are longitudinal spirals, the guide vanes 1-4 with a spiral angle of 10°-25° are selected when grinding lean coal and anthracite, the guide vanes 1-4 with a spiral angle of 25°-80° are selected when grinding bituminous coal and lignite; the static ring block 1-6 and the inner side wall of the medium-speed coal mill are provided with a support ring 1-7; the upper surface of the static ring block 1-6 intersects with the upper surface of the support ring 1-7; the included angle between the upper surface of the support ring 1-7 and the inner side wall of the medium-speed coal mill above is γ, the angle γ is the same as the inclination angle α of the separator body 5 at the grinding roller; the support ring 1-7 is fixedly connected with the static ring block 1-6 and the inner side wall of the medium-speed coal mill, respectively; the guide angle β of the static ring block 1-6 is greater than or equal to 20°; the longitudinal section axis of the guide port 1-3 points to the impeller center axis from bottom to top; the area ratio of the inlet to the outlet of the guide port 1-3 is 1.3-5:1; the moving ring block 1-2 and the guide vane 1-4 are in an integral structure; the moving ring block 1-2 and the extension ring 3 are in an integral structure; the moving ring block 1-2 and the extension ring 3 are connected with the grinding bowl 2 through a vertical axial mechanical bolt.

Claims

1. An impeller assembly for a medium-speed coal mill, characterized in that... The impeller assembly of the medium-speed coal mill includes a dynamic ring assembly (1-1) and a stationary ring assembly (1-5); The moving ring device (1-1) includes a moving ring block (1-2); the moving ring block (1-2) is assembled circumferentially along the extension ring (3); the moving ring block (1-2) is provided with a guide port (1-3) that penetrates the moving ring block, and the longitudinal section of the guide port (1-3) is an outwardly flared asymmetric hyperbolic structure; the guide port (1-3) is provided with a guide vane (1-4), and the guide vane (1-4) is spiral in shape; The stationary ring device (1-5) includes a stationary ring block (1-6), which is provided with a guide angle β. The stationary ring block (1-6) is circumferentially assembled, and the upper surface of the circumferentially assembled stationary ring block (1-6) has an inverted frustum-shaped structure. The stationary ring device (1-5) is located above the moving ring device (1-1), and the stationary ring block (1-6) is adjacent to the upper edge of the outer side of the guide port (1-3); The guiding angle β of the stationary ring block (1-6) is ≥20°; A support ring (1-7) is provided between the stationary ring block (1-6) and the inner wall of the medium-speed coal mill; the upper surface of the stationary ring block (1-6) intersects with the upper surface of the support ring (1-7); the angle between the upper surface of the support ring (1-7) and the inner wall of the medium-speed coal mill is γ, and γ is the same as the inclination angle α of the separator body (5) at the grinding roller; the support ring (1-7) is fixedly connected to the stationary ring block (1-6) and the inner wall of the medium-speed coal mill respectively; the setting of the downward swing angle δ of the support ring (1-7) can increase the angle of the air inlet guide of the moving ring device; The ratio of the inlet and outlet area of ​​the guide port (1-3) is 1.3~5:1; The guide vanes inside the guide port create a diffusion zone. The support ring is set outside the stationary ring block to form a reflux zone, which can send the falling coal powder back into the diffusion zone. At the same time, the airflow in the reflux zone can be used to impede the impact of the coal powder in the diffusion zone on the separator body at the grinding roller. The combination of the outward-curved asymmetrical hyperbolic guide port, the stationary ring block, and the support ring allows hot air to flow in a specific direction within the casing, thus replacing the guide device.

2. The impeller device for a medium-speed coal mill according to claim 1, characterized in that... The guide vanes (1-4) are longitudinal spirals with a spiral angle of 10°~25° or 25°~80°.

3. The impeller device for a medium-speed coal mill according to claim 2, characterized in that... The moving ring block (1-2) is mechanically bolted to the grinding bowl (2) in the vertical axis via the extension ring (3).

4. The impeller device for a medium-speed coal mill according to claim 1, characterized in that... The longitudinal axis of the guide port (1-3) points from bottom to top toward the impeller center axis.

5. The impeller device for a medium-speed coal mill according to claim 4, characterized in that... The moving ring block (1-2) and the guide vane (1-4) are an integral structure.

6. The impeller device for a medium-speed coal mill according to claim 1, 2, 3, 4 or 5, characterized in that... The rotating ring device (1-1) includes multiple rotating ring blocks (1-2) of the same specification.

7. The impeller device for a medium-speed coal mill according to claim 1, 2, 3, 4 or 5, characterized in that... The moving ring block (1-2) and the extension ring (3) are an integral structure.

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