Medium-speed coal mill

Abstract

The invention relates to the technical field of boiler auxiliary machines, and discloses a medium-speed coal mill which is mainly composed of a barrel, a millstone, a milling body, a hot air pipe, a containing groove, a casting piece and a first elastic piece, the millstone is arranged in an inner cavity of the barrel, an arc-shaped groove is formed in the outer side of the upper surface of the millstone, and the milling body is arranged in the inner cavity of the barrel; a hot air pipe is arranged on one side of the barrel, a containing groove is formed in the grinding disc, a casting part is arranged in the containing groove, one end of the casting part is fixedly hinged to the inner wall of the containing groove, and a first elastic part is arranged at the position, located on the lower side of the casting part, in the containing groove. Through the arrangement of the casting piece and the first elastic piece, rolled coal briquettes and pulverized coal are cast to the center position of the grinding disc, then the space between the coal briquettes and the pulverized coal is promoted to be increased, hot air can drive the pulverized coal to move upwards more easily, and through the actions, the pulverized coal discharging efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of boiler auxiliary equipment, and in particular to a medium-speed coal mill. Background Art

[0002] Boiler auxiliary equipment refers to the mechanical equipment attached to the boiler. Among them, the coal mill is a more important type of boiler auxiliary equipment. It is used to process coal blocks into coal powder with higher fineness, thereby improving the utilization rate of coal powder in the boiler.

[0003] Some existing coal mills are mainly composed of a cylinder, a power mechanism, a grinding disc, a grinding body, a lifting mechanism and a separation mechanism. When in use, the coal blocks are transported from the center position of the separation mechanism into the cylinder and fall into the center position of the grinding disc. Afterwards, the grinding disc is driven to rotate by the power mechanism, so that the above-mentioned coal blocks are acted upon by centrifugal force and move toward the edge of the grinding disc and contact the grinding body at the edge of the grinding disc, so that the coal blocks are squeezed and ground by the grinding disc and the grinding body and are crushed. In the above process, hot air is introduced into the lower position of the grinding disc, so that the hot air passes through the space between the grinding disc and the cylinder, flows upward, and contacts the above-mentioned crushed coal powder, so that the coal powder is driven upward by the hot air and contacts the separation mechanism at the uppermost position, so that the coal powder reaching the specified fineness is discharged, and the coal powder that does not reach the specified fineness falls to the center position of the grinding disc again and is crushed again. Through the above actions, the coal grinding operation is realized.

[0004] However, when the coal blocks are squeezed and ground by the grinding disc and the grinding body, the coal blocks are easily mixed with the coal powder particles, which results in part of the coal powder being restricted by the coal blocks when the hot air contacts the coal powder, and thus cannot be effectively driven by the hot air, affecting the coal powder extraction efficiency. Summary of the invention

[0005] The present application proposes a medium-speed coal mill, which has the advantage of promoting the separation of coal blocks and coal powder, and is used to solve the problem that coal blocks restrict coal powder, resulting in low coal powder discharge efficiency.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme: a medium-speed coal mill, comprising: a cylinder, a power mechanism is arranged at the bottom of the cylinder, a grinding disc is arranged in the inner cavity of the cylinder, a rotating shaft is connected to the lower side of the grinding disc, the lower end of the rotating shaft is fixedly connected to the output end of the power mechanism, a conical block is fixed at the center position of the upper surface of the grinding disc, an arc groove is opened on the upper surface of the grinding disc at the outer side of the conical block, a grinding body is arranged equidistantly in the circumferential direction in the inner cavity of the cylinder above the grinding disc, and the grinding body is connected to the lifting mechanism A hot air pipe is provided on one side of the cylinder, and the two ends of the hot air pipe are respectively connected to the external environment and the position below the grinding disc in the inner cavity of the cylinder; the grinding disc is provided with accommodating grooves equidistantly arranged in the circumference below the arc groove, and the notch of the accommodating groove is connected to the arc groove; a projectile is provided in the accommodating groove, and one end of the projectile facing the conical block is hingedly fixed to the inner wall of the accommodating groove; a No. 1 elastic member is provided in the accommodating groove at the lower side of the projectile, and the two ends of the No. 1 elastic member are respectively connected to the projectile and the bottom surface of the accommodating groove.

[0007] Furthermore, limiting grooves are provided on both sides of the projectile, and sliding members are arranged on the inner wall of the accommodating groove at positions corresponding to the limiting grooves, and the sliding members extend into the limiting grooves.

[0008] Furthermore, a sliding groove is opened on the inner wall of the accommodating groove at a position corresponding to the limiting groove, and the sliding member is arranged in the sliding groove. The sliding member is composed of a slider and a limiting block. The slider and the sliding groove are movably connected. A limiting block is fixed on the side of the slider facing the limiting groove, and the limiting block extends into the limiting groove.

[0009] Further, an annular groove is provided on the lower side surface of the grinding disc at the outer position of the rotating shaft, and telescopic parts are equidistantly arranged in the annular groove, and the number of the telescopic parts is the same as the number of the ejection parts; a telescopic groove is provided inside the grinding disc at the upper side of the telescopic part, and the upper end of the telescopic part extends into the telescopic groove, and the telescopic part and the telescopic groove form an active clamping connection; a No. 2 elastic part is provided in the telescopic groove at the upper side of the telescopic part, and the two ends of the No. 2 elastic part are respectively connected to the telescopic part and the inner wall of the telescopic groove; a pull rope is provided at a position between the slide groove and the telescopic part inside the grinding disc, one end of the pull rope extends into the slide groove and is connected to the slider, and the other end of the pull rope extends into the annular groove and is connected to the telescopic part; a ring plate is sleeved on the outer position of the rotating shaft below the grinding disc, and a connecting rod is provided on the outer side of the ring plate, and the two ends of the connecting rod are respectively connected to the ring plate and the inner wall of the cylinder; contact members are equidistantly provided on the upper side of the ring plate, and the contact member is a spherical structure, and the contact member is arranged at a staggered angle with the grinding body, and the contact member extends into the annular groove.

[0010] Furthermore, a through hole is opened in the interior of the grinding disc below the accommodating groove, the upper side of the through hole is connected to the accommodating groove, and the lower side of the through hole is connected to a position below the grinding disc in the cylinder.

[0011] Furthermore, a guide hole is provided inside the projectile, a port on one side of the guide hole is provided on the bottom surface of the projectile, and a port on the other side of the guide hole is provided in the limiting groove.

[0012] Furthermore, the circular cross-sectional area of ​​the through hole is greater than the sum of the circular cross-sectional areas of all the guide holes.

[0013] This application has the following beneficial effects:

[0014] The medium-speed coal mill provided in the present application can project the crushed coal blocks and coal powder toward the center of the grinding disc through the setting of the ejection part and the No. 1 elastic part, thereby increasing the space between the coal blocks and the coal powder, making it easier for the hot air to drive the coal powder to move upward. Through the above-mentioned action, the coal powder extraction efficiency is further improved.

[0015] Through the setting of the ejection piece and the No. 1 elastic piece, the coal block that falls to the center of the grinding disc is affected by the centrifugal force and then moves to the edge of the grinding disc again. Through the above action, the coal block is prompted to continuously change the contact position with the grinding body, so that the coal block is subjected to a better grinding effect.

[0016] By setting the ejection piece, when the ejection piece is extended, it will move the coal blocks and coal powder on both sides, thereby causing the two to change their positions, making it easier for the coal powder to effectively contact the hot air, thereby improving the coal powder discharge efficiency.

[0017] Through the setting of the ejection piece, in the process of the grinding body and the grinding disc squeezing and grinding the coal blocks, the grinding body will produce a certain circumferential driving force on the coal blocks. At this time, the extended ejection piece can produce a certain obstruction on the circumferentially moving coal blocks, prompting more coal blocks to be ground by the grinding body, thereby improving the grinding effect of the coal blocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which constitute a part of the specification, illustrate embodiments disclosed in the present application and, together with the description, serve to explain the principles disclosed in the present application.

[0019] The present application can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0020] Figure 1 This is a schematic diagram of the internal structure of the cylinder in the first embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the internal structure of the grinding disc in the first embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the installation position of the sliding member in the first embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the internal structure of the grinding disc in the second embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the connection state between the telescopic member and the telescopic slot in the second embodiment of the present invention;

[0025] Figure 6 For the present invention Figure 5 A partial enlarged schematic diagram of the structure at center A;

[0026] Figure 7 This is a schematic diagram of the distribution state of the telescopic components in the second embodiment of the present invention;

[0027] Figure 8 This is a schematic diagram of the connection state between the ring plate and the contact piece in the second embodiment of the present invention;

[0028] Fig. 9 This is a schematic diagram of the internal structure of the grinding disc in the third embodiment of the present invention;

[0029] Fig.10 For the present invention Fig. 9 A partial enlarged schematic diagram of the structure at B in the middle;

[0030] Fig.11 This is a schematic diagram of hot air flow in Example 3 of the present invention.

[0031] 1. Cylinder; 2. Grinding disc; 3. Grinding body; 4. Paddle plate; 5. Hot air pipe; 6. Receiving groove; 7. Ejection piece; 8. Elastic piece No. 1; 9. Limiting groove; 10. Sliding piece; 100. Sliding block; 101. Limiting block; 11. Sliding groove; 12. Ring groove; 13. Telescopic piece; 14. Telescopic groove; 15. Elastic piece No. 2; 16. Pull rope; 17. Ring plate; 18. Connecting rod; 19. Contact piece; 20. Through hole; 21. Diversion hole. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] Embodiment 1

[0034] See also Figure 1 and Figure 2A medium-speed coal mill comprises a cylinder 1, a power mechanism (existing technology, such as a motor) is arranged at the bottom of the cylinder 1, a grinding disc 2 is arranged at the central position of the inner cavity of the cylinder 1, a rotating shaft is fixed at the central position of the lower side of the grinding disc 2, and the lower end of the rotating shaft is fixedly connected with the output end of the power mechanism, a conical block is fixed at the central position of the upper surface of the grinding disc 2, an arc groove is provided on the upper surface of the grinding disc 2 outside the conical block, inclined plates are fixedly arranged at equal intervals on the circumferential side of the grinding disc 2, a grinding body 3 is equidistantly arranged circumferentially above the grinding disc 2 in the inner cavity of the cylinder 1, the grinding body 3 is connected with a lifting mechanism (existing technology, such as a hydraulic rod), the lower side of the grinding body 3 extends into the arc groove, a dial plate 4 is arranged at the lower side of the grinding disc 2, and the dial plate 4 is fixedly connected with the rotating shaft at one end facing the rotating shaft. A collecting chamber is provided inside the cylinder 1 at the outer side of the power mechanism, and the upper opening of the collecting chamber is provided on the bottom surface of the inner cavity of the cylinder 1. A hot air pipe 5 is provided on one side of the cylinder 1, and the two ends of the hot air pipe 5 are respectively connected to the external environment and the position of the inner cavity of the cylinder 1 where the paddle 4 is located. The grinding disc 2 is provided with accommodating grooves 6 equidistantly arranged at the lower position of the arc groove. The notch of the accommodating groove 6 is connected with the arc groove. A projectile 7 is slidably installed in the accommodating groove 6. The upper side surface of the projectile 7 and the bottom surface of the arc groove are at the same arc. One end of the projectile 7 facing the conical block is hinged and fixed to the inner wall of the accommodating groove 6. A No. 1 elastic member 8 is provided in the accommodating groove 6 at the lower side of the projectile 7. The two ends of the No. 1 elastic member 8 are respectively connected to the projectile 7 and the bottom surface of the accommodating groove 6. Before work, the power mechanism drives the grinding disc 2 to rotate, and at the same time, the lifting mechanism drives the grinding body 3 to move downward, and a small distance is left between the grinding body 3 and the arc groove. Then, the coal block is transported into the cylinder 1, and the coal block falls to the center position of the grinding disc 2, so that the coal block is subjected to the centrifugal force and then falls into the arc groove. Afterwards, as the grinding disc 2 continues to rotate, the above-mentioned coal block is squeezed and ground by the grinding disc 2 and the grinding body 3, and then is crushed. At the same time, hot air is passed into the cylinder 1 through the hot air pipe 5, so that the hot air passes through the space between the grinding disc 2 and the cylinder 1, and then flows upward, and contacts the above-mentioned crushed coal powder, so that the coal powder is driven upward by the hot air. In the process of the above-mentioned coal block entering the arc groove, part of the coal block will be at the inner position of the ejection member 7. Then When the grinding body 3 is close to the ejection piece 7, it will press the ejection piece 7 and the coal block inside the ejection piece 7, so that the ejection piece 7 is received in the receiving groove 6 and the first elastic piece 8 is compressed. At this time, the crushed coal block is on the upper side of the ejection piece 7. Afterwards, when the grinding body 3 leaves the ejection piece 7, the first elastic piece 8 is reset, so that the ejection piece 7 drives the coal block and coal powder on its upper side to be ejected toward the center position of the grinding disc 2, thereby increasing the space between the coal block and the coal powder, making it easier for the hot air to drive the coal powder to move upward. Through the above actions, the coal powder discharge efficiency is improved. At the same time, when the ejection piece 7 is extended again, it will move the coal blocks and coal powder on both sides, thereby causing the two to change their positions, making it easier for the coal powder to effectively contact with the hot air, thereby further improving the coal powder discharge efficiency. Afterwards,The coal blocks falling to the center of the grinding disc 2 are affected by the centrifugal force and move toward the arc groove again. Through the above action, the coal blocks are constantly changing the contact position with the grinding body 3, so that the grinding effect of the coal blocks is better. In addition, in the process of the grinding body 3 and the grinding disc 2 squeezing and grinding the coal blocks, the grinding body 3 will produce a certain circumferential driving force on the coal blocks. At this time, the extended ejection piece 7 is used to produce a certain blockage on the circumferentially moving coal blocks, so that the coal blocks between the grinding body 3 and the ejection piece 7 accumulate to a certain extent, and then more coal blocks are ground by the grinding body 3, so that the grinding effect of the coal blocks is improved.

[0035] See also Figure 2 and Figure 3 Limiting grooves 9 are provided on both sides of the ejection member 7, and a sliding member 10 is arranged at a position corresponding to the limiting groove 9 on the inner wall of the accommodating groove 6, and the sliding member 10 extends into the limiting groove 9. Through the arrangement of the above structure, when the ejection member 7 is extended again, it will hit the sliding member 10 through the limiting groove 9. Through the above action, the ejection member 7 vibrates, which causes the coal powder attached to the surface of the ejection member 7 to separate.

[0036] Embodiment 2

[0037] See also Figure 4-Figure 6 This embodiment is a further improvement of the first embodiment, and the improvement lies in that a slide groove 11 is provided on the inner wall of the accommodating groove 6 at a position corresponding to the limiting groove 9, and the sliding member 10 is slidably installed in the slide groove 11. The sliding member 10 is composed of a slider 100 and a limiting block 101. The slider 100 forms a sliding connection with the slide groove 11. The limiting block 101 is fixedly installed on the side of the slider 100 facing the limiting groove 9, and the limiting block 101 extends into the limiting groove 9. Through the arrangement of the above structure, when the ejection member 7 is extended again, the sliding member 10 will be driven by the limiting groove 9, so that the slider 100 hits the upper side wall of the slide groove 11. Through the above action, the ejection member 7 vibrates, which causes the coal powder attached to the surface of the ejection member 7 to separate.

[0038] See also Figure 1 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8The lower side of the grinding disc 2 is provided with an annular groove 12 at the outer side of the rotating shaft, and telescopic members 13 are arranged at equal intervals in the annular groove 12. The number of telescopic members 13 is the same as the number of ejection members 7. A telescopic groove 14 is provided inside the grinding disc 2 at the upper side of the telescopic member 13. The upper end of the telescopic member 13 extends into the telescopic groove 14. The telescopic member 13 and the telescopic groove 14 form a sliding connection. A second elastic member 15 is provided in the telescopic groove 14 at the upper side of the telescopic member 13. The two ends of the second elastic member 15 are respectively connected to the telescopic member 13 and the telescopic groove 1 4, a pull rope 16 is arranged inside the grinding disc 2 between the slide groove 11 and the telescopic member 13, one end of the pull rope 16 extends into the slide groove 11 and is fixedly connected to the slider 100, the other end of the pull rope 16 extends into the annular groove 12 and is connected to the telescopic member 13, a ring plate 17 is sleeved on the outer side of the rotating shaft below the grinding disc 2, a connecting rod 18 is arranged on the outer side of the ring plate 17, the two ends of the connecting rod 18 are respectively connected to the ring plate 17 and the inner wall of the cylinder 1, and contact members 19 are equidistantly arranged on the upper side of the ring plate 17, and the contact members 19 are The spherical structure is set, and the contact member 19 is set at a staggered angle with the grinding body 3. The contact member 19 extends into the annular groove 12. During the rotation of the grinding disc 2, the telescopic member 13 is driven to first approach the grinding body 3. Then, when the telescopic member 13 just leaves the grinding body 3, the telescopic member 13 contacts the contact member 19, so that the contact member 19 drives the telescopic member 13 to move upward and compresses the second elastic member 15, so that the pull rope 16 drives the sliding member 10 to move to the lower position of the sliding groove 11, so that the projectile member 7 is limited by the sliding member 10 at this time, and then It cannot extend outward. Later, as the grinding disc 2 continues to rotate, the contact member 19 and the telescopic member 13 move away from each other (the telescopic member 13 is now in the middle position range of the adjacent grinding body 3). The second elastic member 15 and the first elastic member 8 release their elastic force at the same time, causing the telescopic member 13 to move downward, while the ejection member 7 extends out. Through the above-mentioned action, the ejection member 7 is prevented from being affected by the grinding body 3 during its extension, and gradually moves upward along the curved surface of the grinding body 3, thereby being unable to produce an ejection action on the coal blocks and coal powder on the upper side of the ejection member 7.

[0039] Embodiment 3

[0040] See also Figure 1 , Figure 5 , Fig. 9 , Fig.10 and Fig.11This embodiment is a further improvement of the first embodiment, and the improvement lies in that a through hole 20 is provided inside the grinding disc 2 below the accommodating groove 6, the upper side of the through hole 20 is connected with the accommodating groove 6, and the lower side of the through hole 20 is connected with the position below the grinding disc 2 in the cylinder 1. Through the setting of the through hole 20, the elastic force of the second elastic member 15 and the first elastic member 8 is released at the same time, so that the telescopic member 13 moves downward, and during the extension of the ejection member 7, part of the hot air will pass through the through hole 20, thereby applying a thrust to the ejection member 7, so that the extension speed of the ejection member 7 is accelerated, thereby improving the ejection effect of the ejection member 7 on the upper coal blocks and coal powder.

[0041] A guide hole 21 is provided inside the ejection piece 7, one side port of the guide hole 21 is provided on the bottom surface of the ejection piece 7, and the other side port of the guide hole 21 is provided in the limiting groove 9. The circular cross-sectional area of ​​the through hole 20 is greater than the sum of the circular cross-sectional areas of all the guide holes 21. In the process of the hot air pushing the ejection piece 7 to extend, part of the hot air will pass through the guide hole 21 and then blow out along the limiting groove 9. Through the above action, the limiting groove 9 is cleaned. At the same time, the hot air blown out along the limiting groove 9 will blow the coal blocks and coal powder on both sides of the ejection piece 7 to move, thereby prompting the two to change their positions, so that the coal powder is easier to effectively contact with the hot air, thereby further improving the coal powder discharge efficiency. At the same time, the hot air cooperates with the extended ejection piece 7 to produce a stronger barrier to the coal blocks that move circumferentially, prompting a certain degree of accumulation of the coal blocks between the grinding body 3 and the ejection piece 7, thereby prompting more coal blocks to be ground by the grinding body 3, so that the grinding effect of the coal blocks is improved.

[0042] The opening angle of the port on the other side of the guide hole 21 can be adaptively adjusted according to actual conditions.

[0043] The structure size, length, etc. in the above-mentioned embodiments 1 and 2 can be adaptively adjusted according to actual conditions.

Claims

1. A medium-speed coal mill, comprising: A cylinder (1) is provided with a power mechanism at the bottom of the cylinder (1), a grinding disc (2) is provided in the inner cavity of the cylinder (1), a rotating shaft is connected to the lower side of the grinding disc (2), the lower end of the rotating shaft is fixedly connected to the output end of the power mechanism, a conical block is fixed at the center position of the upper surface of the grinding disc (2), an arc groove is provided on the upper surface of the grinding disc (2) at the outer side of the conical block, a grinding body (3) is equidistantly provided in the circumferential direction in the inner cavity of the cylinder (1) above the grinding disc (2), the grinding body (3) is connected to the lifting mechanism, a hot air pipe (5) is provided on one side of the cylinder (1), and the hot air pipe (5) The two ends of the cylindrical body (1) are respectively connected to the external environment and the position below the grinding disc (2) in the inner cavity of the cylindrical body (1), and the character is characterized in that the grinding disc (2) is provided with accommodating grooves (6) equidistantly arranged in the circumference below the arc groove, the notch of the accommodating groove (6) is connected to the arc groove, a projectile (7) is arranged in the accommodating groove (6), one end of the projectile (7) facing the conical block is hingedly fixed to the inner wall of the accommodating groove (6), and a first elastic member (8) is arranged in the accommodating groove (6) at the lower side of the projectile (7), and the two ends of the first elastic member (8) are respectively connected to the projectile (7) and the bottom surface of the accommodating groove (6).

2. A medium speed coal mill according to claim 1, characterized in that: Limiting grooves (9) are provided on both sides of the projectile member (7), and a sliding member (10) is provided on the inner wall of the accommodating groove (6) at a position corresponding to the limiting groove (9), and the sliding member (10) extends into the limiting groove (9).

3. A medium speed coal mill according to claim 2, characterized in that: A sliding groove (11) is provided on the inner wall of the accommodating groove (6) at a position corresponding to the limiting groove (9); the sliding member (10) is arranged in the sliding groove (11); the sliding member (10) is composed of a slider (100) and a limiting block (101); the slider (100) and the sliding groove (11) are movably connected; the limiting block (101) is fixed on the side of the slider (100) facing the limiting groove (9); and the limiting block (101) extends into the limiting groove (9).

4. A medium speed coal mill according to claim 3, characterized in that: The lower side of the grinding disc (2) is provided with an annular groove (12) at an outer position of the rotating shaft, and the inner cavity of the annular groove (12) is equidistantly provided with telescopic parts (13), and the number of the telescopic parts (13) is the same as the number of the ejection parts (7). The interior of the grinding disc (2) is provided with a telescopic groove (14) at an upper position of the telescopic part (13), and the upper end of the telescopic part (13) extends into the telescopic groove (14), and the telescopic part (13) and the telescopic groove (14) form a movable clamping connection. The inner cavity of the telescopic groove (14) and the upper position of the telescopic part (13) are provided with a second elastic part (15), and the two ends of the second elastic part (15) are respectively connected to the inner wall of the telescopic part (13) and the inner wall of the telescopic groove (14). The interior of the grinding disc (2) and the position between the slide groove (11) and the telescopic part (13) are provided with a second elastic part (15). A pull rope (16) is arranged at a position between the two ends of the pull rope (16), one end of the pull rope (16) extends into the slide groove (11), one end of the pull rope (16) is connected to the slider (100), the other end of the pull rope (16) extends into the annular groove (12), and the other end of the pull rope (16) is connected to the telescopic member (13). A ring plate (17) is sleeved on the outer side of the rotating shaft below the grinding disc (2), a connecting rod (18) is arranged on the outer side of the ring plate (17), and the two ends of the connecting rod (18) are respectively connected to the ring plate (17) and the inner wall of the cylinder (1), and a contact member (19) is equidistantly arranged on the upper side surface of the ring plate (17), the contact member (19) is a spherical structure, the contact member (19) and the grinding body (3) are arranged at a staggered angle, and the contact member (19) extends into the annular groove (12).

5. A medium speed coal mill according to claim 2, characterized in that: A through hole (20) is provided inside the grinding disc (2) and below the receiving groove (6); the upper side of the through hole (20) is connected to the receiving groove (6), and the lower side of the through hole (20) is connected to a position below the grinding disc (2) in the cylinder (1).

6. A medium speed coal mill according to claim 5, characterized in that: A guide hole (21) is provided inside the ejection member (7), one side port of the guide hole (21) is opened on the bottom surface of the ejection member (7), and the other side port of the guide hole (21) is opened in the limiting groove (9).

7. A medium speed coal mill according to claim 6, characterized in that: The circular cross-sectional area of ​​the through hole (20) is greater than the sum of the circular cross-sectional areas of all the flow guide holes (21).

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