Barrel structure for steel ball coal mill

Abstract

The invention discloses a barrel structure for a steel ball coal mill, which comprises a barrel with two closed ends, a transmission shaft and an annular bin, and the transmission shaft is coaxially positioned in an inner cavity of the barrel, penetrates through the two ends and is fixedly connected with the barrel; the annular outer wall of the annular bin is connected to the inner wall of the middle of the barrel in a bolted mode so that an inner cavity of the barrel can be divided into a first bin chamber and a second bin chamber which are equal in volume. The annular inner wall of the annular bin is fixedly arranged on the transmission shaft in a sleeving mode, and a notch is formed in the annular inner wall, opposite to the transmission shaft, of the annular bin so as to communicate the first bin with the second bin to balance the material level. The annular bin is installed in the middle of the barrel, on one hand, the annular bin can occupy the space of the barrel, then the effective volume in the barrel is reduced, and the steel ball loading coefficient is increased by reducing the effective volume of the barrel; on the other hand, the inner cavity of the barrel can be divided into two chambers with the same volume through the annular bin, the balance of the raw coal amount and the steel ball amount in the two chambers is kept through the notch, and it is guaranteed that the steel balls are separated in the two chambers.

Description

Technical Field

[0001] The invention relates to the technical field of steel ball pulverizing and grinding, and more particularly to a cylinder structure for a steel ball coal mill. Background Art

[0002] Double-inlet and double-outlet ball mills are widely used in coal-fired thermal power generation units. The ratio of the volume of the steel balls in the cylinder of the ball mill to the cylinder volume is called the steel ball loading coefficient. Each specification of ball mill has an optimal steel ball loading coefficient, at which the unit power consumption of pulverizing is the smallest. In order to reduce the power consumption of pulverizing, power plants will take measures to reduce the amount of balls to reduce the current of the main motor while ensuring the output of pulverizing, which results in the steel ball loading coefficient of many ball mills in actual operation being lower than the optimal steel ball loading coefficient. In particular, the less-ball technology that has emerged in recent years can reduce the amount of balls by more than 15% while ensuring the output of the coal mill by optimizing the grading of the steel balls, further reducing the steel ball loading coefficient.

[0003] The double-inlet and double-outlet ball mill adopts a pressure differential level control system for automatic coal feeding control. The condition for normal operation is that the lower pressure differential pipeline is inserted into the fine coal powder layer. As the amount of steel balls in the cylinder decreases, the total amount of the mixture of steel balls, raw coal particles and fine coal powder also decreases. When the pressure is so low that the lower pressure differential pipeline cannot be inserted into the fine coal powder layer, the pressure differential level control system becomes ineffective.

[0004] With the application of less-ball technology, the failure of differential pressure level control systems has become more and more common, posing a great threat to the normal production of power plants.

[0005] Therefore, how to ensure that the steel ball loading coefficient is increased by reducing the internal volume of the cylinder without changing the size of the coal mill cylinder, and at the same time not reducing the amount of steel balls in the cylinder, so that the originally too low steel ball loading coefficient is increased to the optimal steel ball loading coefficient, is an issue that technical personnel in this field urgently need to solve. Summary of the invention

[0006] In view of this, the present invention provides a cylinder structure for a steel ball coal mill, which utilizes an annular bin to occupy the inner cavity of the cylinder, thereby reducing the effective volume of the cylinder without changing the structural dimensions of the cylinder and without reducing the amount of steel balls, thereby increasing the originally too low steel ball loading coefficient to an optimal steel ball loading coefficient.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A cylinder structure for a steel ball coal mill comprises a cylinder with both ends closed, a transmission shaft and an annular bin.

[0009] A ball adding port is provided at one end of the cylinder, and coal adding ports are provided at both ends thereof; the transmission shaft is coaxially located in the inner cavity of the cylinder and passes through both ends thereof and is fixedly connected thereto; the annular outer wall of the annular bin is bolted to the middle inner wall of the cylinder to divide the inner cavity of the cylinder into a first chamber and a second chamber with equal volumes; the annular inner wall of the annular bin is sleeved and fixed on the transmission shaft, and a notch is provided in the annular inner wall of the annular bin relative to the transmission shaft to connect the first chamber and the second chamber to balance the material level.

[0010] The beneficial effect of the technical solution of the present invention is that, by installing the annular bin in the middle part of the cylinder, the annular bin can, on the one hand, occupy the space of the cylinder, thereby reducing the effective volume in the cylinder, thereby increasing the steel ball loading coefficient by reducing the effective volume of the cylinder; on the other hand, the annular bin can divide the inner cavity of the cylinder into two chambers with equal volumes, and maintain the balance of the amount of raw coal and the amount of steel balls in the two chambers through the gap, ensuring that the steel balls are separated in the two chambers.

[0011] Preferably, the annular warehouse comprises a first annular warehouse body and a second annular warehouse body;

[0012] The first ring warehouse body has an outer ring surface 1 and two side ring surfaces 1, one end of the two side ring surfaces 1 are respectively connected to the two ends of the outer ring surface 1 along its axial direction, and the other end is inclined toward the central axis of the first ring warehouse body and close to each other to form a first inclined surface, and the side of the two first inclined surfaces corresponding to the central axis of the first ring warehouse body is the inner ring side of the first ring warehouse body;

[0013] The second ring warehouse body has an outer ring surface 2, two side ring surfaces 2 and an inner ring surface, and the outer ring surface 2 is coaxially adapted and fixed on the inner ring side of the first ring warehouse body; one end of the two side ring surfaces 2 are respectively connected to the two ends of the outer ring surface 2 along its axial direction, and the other end is respectively connected to the two ends of the inner ring surface along its axial direction, and the other ends of the two side ring surfaces 2 are inclined toward the central axis of the second ring warehouse body and close to each other to form a second inclined surface.

[0014] The beneficial effect of the above technical solution is that the filling density of the mixture of steel balls, raw coal particles and fine coal powder in the cylinder is raised by the inclined surface, which facilitates the circulation of steel balls and raw coal in the cylinder through the gap in the two chambers.

[0015] Preferably, the inclination angle of the second inclined surface is greater than that of the first inclined surface. The filling density of the mixture of steel balls, raw coal particles and fine coal powder in the cylinder is raised by inclined surfaces with different inclination angles to ensure that the steel balls and raw coal can flow between the two chambers.

[0016] Preferably, it further comprises a wedge block, and a plurality of grooves are formed on the inner ring surface of the second ring bin body; the number of the wedge blocks is multiple, and the plurality of wedge blocks are fixed one by one on the groove side walls of the plurality of grooves facing the rotation direction of the cylinder body. The grooves can make the side with high ball and coal levels in the first chamber and the second chamber flow to the side with low ball and coal levels, facilitating the circulation of steel balls and raw coal in the two chambers and ensuring the balance of material levels in the two chambers. The wedge blocks can prevent the steel balls from rotating in the grooves as the cylinder body rotates, thereby affecting the balance of the steel balls in the two chambers.

[0017] Preferably, the first inclined surface and the second inclined surface are both fixed with a wear-resistant layer, and the wear-resistant layer is formed by splicing a plurality of first lining plates or by bimetallic surfacing, thereby increasing the service life of the annular bin.

[0018] Preferably, a plurality of bolt holes are provided on both the first inclined surface and the second inclined surface, the first lining plate is a fan-shaped structure, a convex ridge is fixed on a side panel away from the first inclined surface or the second inclined surface, the convex ridge is provided with a countersunk hole corresponding to the bolt hole, and the threaded end of the fastening bolt passes through the countersunk hole and the bolt hole in sequence to fasten the first lining plate to the first inclined surface or the second inclined surface. The first lining plate is detachably connected to the first ring bin body and the second ring bin body, which is convenient for later maintenance and replacement.

[0019] Preferably, the angle α between the first inclined surface and the annular outer wall of the first annular bin body is 70° to 90°; the angle β between the second inclined surfaces on both sides of the second annular bin body is 40° to 60°. The filling density of the mixture of steel balls, raw coal particles and fine coal powder in the cylinder is increased by inclined surfaces with different inclination angles, ensuring that the steel balls and raw coal can flow between the two chambers.

[0020] Preferably, the wedge block is an internal hollow structure, and the angle between the two wedge-shaped inclined surfaces of the wedge block is The angle is 40° to 60°. The two wedge-shaped inclined surfaces of the wedge block form a spherical surface, which can prevent the steel ball in the groove from rotating with the rotating cylinder, ensuring that the steel ball circulates between the two chambers.

[0021] Preferably, the groove has a depth of 150 to 300 mm and is greater than the outer diameter of the steel ball, so as to ensure that the steel ball can flow through the two chambers through the groove.

[0022] Preferably, the outer ring surface of the first annular bin body is bolted to the inner wall of the middle part of the cylinder; the inner ring surface of the second annular bin body is pressed and matched with the outer wall of the transmission shaft. The annular bin divides the inner cavity of the cylinder into two chambers of equal volume. At the same time, the annular bin will occupy the space in the cylinder, effectively reducing the volume of the cylinder without changing the structure of the cylinder. The filling degree of the mixture of steel balls, raw coal particles and fine coal powder is increased by setting the inclined surface. With the groove and the wedge block, the circulation of raw coal and steel balls between the two chambers can be ensured, thereby ensuring the balance of the amount of raw coal and steel balls in the first chamber and the second chamber.

[0023] Preferably, a second lining plate is bolted to the inner wall of the cylinder, and the wear resistance of the cylinder is improved by the second lining plate.

[0024] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a cylinder structure for a steel ball coal mill, which utilizes the annular bin to occupy the space of the cylinder, thereby reducing the effective volume in the cylinder, and improving the steel ball loading factor of the steel ball coal mill by reducing the effective volume of the cylinder, so that the steel ball loading factor that is originally too low is increased to the optimal steel ball loading factor;

[0025] The design of the annular bin slope can raise the filling level of the steel balls, raw coal particles and fine coal powder mixture in the cylinder; the design of the grooves and wedge blocks can ensure that the material levels of the raw coal and steel balls in the cylinder relative to the two sides of the annular bin are in a balanced state;

[0026] The present invention has an obvious effect on improving the pulverizing capacity of the ball mill and reducing the power consumption and steel consumption of pulverizing. In addition, it can restore the pressure difference material level control system that fails due to too low loading factor, which is of great significance to ensuring the economical and stable operation of the generator set. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 The schematic diagram of the annular bin structure in the cylinder structure of the ball coal mill according to the present invention;

[0029] Figure 2 It is a schematic diagram of the structure of the annular bin in the cylinder structure of the steel ball coal mill after the wear-resistant layer is installed in the annular bin in the cylinder structure of the steel ball coal mill according to the present invention;

[0030] Figure 3 for Figure 2 Schematic diagram of a half-section of an annular warehouse;

[0031] Figure 4 It is a schematic diagram of the arrangement of grooves in the cylinder structure of a steel ball coal mill according to the present invention;

[0032] Figure 5 It is a cross-sectional view of a wedge block in a cylinder structure of a steel ball coal mill according to the present invention;

[0033] Figure 6 It is a schematic diagram of the first lining plate structure in the cylinder structure of the steel ball coal mill according to the present invention;

[0034] Figure 7 It is a cross-sectional view of the cylinder in the cylinder structure of the ball coal mill of the present invention;

[0035] Figure 8 It is a schematic diagram of the structure of the second lining plate in the cylinder structure of the steel ball coal mill according to the present invention;

[0036] Fig. 9 This is a measurement principle diagram of the pressure difference material level control system in Example 2 of the present invention;

[0037] Fig.10 This is a schematic diagram of the pressure difference material level control system in Example 2 of the present invention.

[0038] in,

[0039] 1-first annular chamber; 11-first inclined surface; 12-first cavity;

[0040] 2-second annular chamber; 21-second inclined surface; 22-groove; 23-second cavity;

[0041] 3-wedge block; 31-wedge inclined surface; 32-straight plane;

[0042] 4-first lining plate; 41-convex ridge; 42-counterbore;

[0043] 5- cylinder; 51- first chamber; 52- second chamber;

[0044] 6- Second lining plate;

[0045] 7-Screw propeller. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Embodiment 1:

[0048] See attached Figures 1 to 6 The embodiment of the present invention discloses a cylinder structure for a steel ball coal mill, comprising a cylinder 5 with both ends closed, a transmission shaft and an annular bin.

[0049] A ball adding port is provided at one end of the cylinder 5, and coal adding ports are provided at both ends thereof; the transmission shaft is coaxially located in the inner cavity of the cylinder 5 and passes through both ends thereof and is fixedly connected thereto; the annular outer wall of the annular bin is bolted to the middle inner wall of the cylinder 5 to divide the inner cavity of the cylinder 5 into two first chambers 51 and second chambers 52 of equal volume; the annular inner wall of the annular bin is sleeved and fixed on the transmission shaft, and a notch is provided on the annular inner wall of the annular bin relative to the transmission shaft to connect the first chamber 51 and the second chamber 52 to balance the material level.

[0050] like Figure 7 As shown, the cylinder structure disclosed in this embodiment is applied to a double-inlet and double-outlet steel ball coal mill. By installing the annular bin in the middle of the inner cavity of the cylinder, the annular bin can occupy the space of the cylinder on the one hand, thereby reducing the effective volume in the cylinder, thereby increasing the steel ball loading coefficient by reducing the effective volume of the cylinder; on the other hand, the annular bin can divide the inner cavity of the cylinder into two chambers with equal volumes, and the gap is used to maintain the balance of the amount of raw coal and the amount of steel balls in the two chambers, ensuring that the steel balls are separated in the two chambers.

[0051] like Figure 1 As shown, the annular warehouse includes a first annular warehouse body 1 and a second annular warehouse body 2;

[0052] The first ring warehouse body 1 has an outer ring surface 1 and two side ring surfaces 1, one end of the two side ring surfaces 1 is respectively connected to the two ends of the outer ring surface 1 along its axial direction, and the other end is inclined toward the central axis of the first ring warehouse body 1 and close to each other to form a first inclined surface 11, and the side of the two first inclined surfaces 11 corresponding to the central axis of the first ring warehouse body 1 is the inner ring side of the first ring warehouse body 1;

[0053] The second ring warehouse body 2 has an outer ring surface 2, two side ring surfaces 2 and an inner ring surface. The outer ring surface 2 is coaxially adapted and fixed on the inner ring side of the first ring warehouse body 1; one end of the two side ring surfaces 2 are respectively connected to the two ends of the outer ring surface 2 along its axial direction, and the other end is respectively connected to the two ends of the inner ring surface along its axial direction. The other ends of the two side ring surfaces 2 are inclined toward the center axis of the second ring warehouse body 2 and close to each other to form a second inclined surface 21.

[0054] In order to further optimize the above technical solution, the inclination angle of the second inclined surface 21 is greater than the inclination angle of the first inclined surface 11. The angle α between the first inclined surface 11 and the outer ring surface 1 of the first ring warehouse body 1 is 70° to 90°; the angle β between the second inclined surfaces 21 on both sides of the second ring warehouse body 2 is 40° to 60°.

[0055] See attached Figure 3The first ring bin body and the second ring bin body as a whole form a structure similar to a cone in half cross section. The cone structure can ensure that the steel balls and raw coal can flow between the first chamber and the second chamber through the gap, ensuring the balance of the coal position and the ball position in the first chamber and the second chamber.

[0056] In order to further optimize the above technical solution, it also includes a wedge block 3, and a plurality of grooves 22 are opened on the inner ring surface of the second ring warehouse body 2; there are multiple wedge blocks 3, and the multiple wedge blocks 3 are fixed one by one on the groove side walls of the multiple grooves 22 facing the rotation direction of the cylinder 5.

[0057] The annular bin divides the cylinder into a first chamber and a second chamber of equal volume. At the same time, the annular bin occupies the space of the cylinder, thereby achieving the purpose of reducing the effective volume of the cylinder, thereby increasing the loading coefficient of the steel balls in the cylinder. The space occupied by the annular bin is determined according to the actual amount of balls loaded in the cylinder.

[0058] In order to further optimize the above technical solution, the wedge block 3 can be set as a hollow structure inside, the wedge block 3 has two wedge-shaped inclined surfaces 31 and a straight plane 32 connecting the two wedge-shaped inclined surfaces 31, and the angle between the two wedge-shaped inclined surfaces 31 is 40°~60°. Figure 1 As shown, the straight plane and the wedge-shaped inclined surface of the wedge block together form a spherical surface. The conical design can prevent the steel ball from rotating in the groove as the cylinder rotates. The setting of the wedge block can ensure the flow of the steel ball between the two chambers, and the hollow structure can reduce the energy consumption during the rotation of the cylinder.

[0059] The ball adding device of the double-inlet and double-outlet ball mill is arranged at one end of the cylinder opposite to the ball adding port, and steel balls are always added from one end, which will cause the amount of steel balls in the chamber on the ball adding side to be greater than that on the other side; the raw coal enters the cylinder from the coal adding ports at both ends of the cylinder, and sometimes the amount of coal entering the two ends is not equal, and the amount of raw coal in the chamber on the end with a larger coal input is greater than that on the other end; therefore, the side with a higher ball and coal level can flow to the lower side through the groove, and the design of the groove can keep the amount of steel balls and raw coal in the first chamber and the second chamber balanced, and the design of the wedge block can prevent the steel balls in the groove from rotating with the rotation of the cylinder, thereby affecting the flow of the steel balls between the two chambers.

[0060] Specifically, in order to ensure that the bottom wall of the groove is lower than the surface of the mixture of steel balls and raw coal, the groove depth of the groove 22 is 150-300 mm and greater than the outer diameter of the steel balls. The design of the first inclined surface, the second inclined surface and the groove can ensure the circulation of steel balls and raw coal in the first chamber and the second chamber.

[0061] In order to further optimize the above technical solution, a first cavity 12 is formed between the two first inclined surfaces 11 on both sides of the first ring bin body 1, and a second cavity 23 is formed between the two second inclined surfaces 21 on both sides of the second ring bin body 2, and the first cavity 12 and the second cavity 23 are connected. The first ring bin body and the second ring bin body form an annular hollow bin with an integrated structure, and the hollow design can avoid the coal mill rotating part from consuming more energy due to excessive weight, resulting in waste of resources.

[0062] In some specific embodiments, a wear-resistant layer may be fixed on both the first inclined surface 11 and the second inclined surface 21 , and the wear-resistant layer is formed by splicing a plurality of first lining plates 4 or by bimetallic surfacing.

[0063] like Figure 2 As shown, the wear-resistant layer in this embodiment is formed by splicing multiple first lining plates, and multiple bolt holes are provided on the first inclined surface 11 and the second inclined surface 21. The first lining plate 4 is a fan-shaped structure, and a convex ridge 41 is fixed on a side panel away from the first inclined surface 11 or the second inclined surface 21. The convex ridge 41 is provided with a countersunk hole 42 corresponding to the bolt hole, and the threaded end of the fastening bolt passes through the countersunk hole 42 and the bolt hole in sequence to fasten the first lining plate 4 to the first inclined surface 11 or the second inclined surface 21.

[0064] In order to further improve the wear resistance of the annular bin, NM400 wear-resistant steel plates are welded on the annular inner wall of the second bin body, the groove wall of the groove and the outer surface of the wedge block.

[0065] In order to further optimize the above technical solution and facilitate the installation of the annular bin, the annular bin can be evenly divided into 4 to 6 sector-shaped bodies along the circumferential direction and then welded into a whole inside the cylinder.

[0066] In order to further optimize the above technical solution and improve the wear resistance of the cylinder, a second lining plate 6 is bolted to the inner wall of the cylinder 5. Figure 8 As shown, the second lining plate is made of high chromium cast iron or wear-resistant cast steel and is evenly distributed along the circumferential direction of the inner wall of the cylinder.

[0067] Embodiment 2:

[0068] The embodiment of the present invention discloses a method for improving the loading coefficient of steel balls in a ball mill, using the annular bin in Example 1, wherein the outer annular surface of the first annular bin body 1 is bolted to the middle inner wall of the cylinder body 5; the inner annular surface of the second annular bin body 2 is pressed tightly against the outer wall of the transmission shaft.

[0069] The double-inlet and double-outlet ball mill conveys raw coal into the cylinder at both ends at the same time, and the coal powder is also conveyed out from both ends of the cylinder. The amount of coal in the cylinder is affected by the difference between the amount of raw coal entering the cylinder and the amount of coal powder discharged from the cylinder. When the amount of raw coal entering is more than the amount of coal powder discharged, the amount of coal in the cylinder decreases, and vice versa. In order to ensure that the amount of coal in the cylinder is always within a reasonable range, the double-inlet and double-outlet ball mill adopts a pressure differential level control system. The measurement principle of the pressure differential level control system is shown in Fig. 9 The upper part of the chamber is filled with air and the pressure P0 is kept constant. The lower part of the chamber is filled with a fluid with a density of ρ. When the low-speed airflow flows into the chamber through the upper pressure measuring tube, the pressure in the upper pressure measuring tube is P 上 The deviation from the pressure P0 in the chamber is extremely small and can be ignored, that is, P 上 =P0. The lower pressure gauge is inserted at a depth of h below the fluid surface. When the low-speed airflow flows into the chamber through the lower pressure gauge, the pressure P 下 =P0+ρgh. The pressure difference between the lower and upper pressure measuring tubes ΔP = P 下 -P 上 =ρgh, so by measuring the pressure difference between the lower pressure measuring tube and the upper pressure measuring tube, the depth h of the lower pressure measuring tube below the liquid surface can be calculated.

[0070] Using this principle, two pressure measuring tubes, one upper and one lower, are installed at each end of the cylinder. Fig.10 The upper pressure measuring tube is located directly above the screw propeller 7, and the lower pressure measuring tube is located directly below the screw propeller 7. The lower pressure measuring tube is L-shaped, and one end of the lower pressure measuring tube cylinder is bent downward. The upper space in the cylinder is filled with air and coal powder suspended in the air, and the lower space is filled with steel balls, raw coal particles and fine coal powder. The steel balls and raw coal particles are mixed together, and the fine coal powder is filled in the gap formed by the steel balls and the raw coal particles.

[0071] There is a low-speed airflow in the pressure measuring tube. The outlet of the upper pressure measuring tube is placed in the air and suspended coal powder. The pressure in the upper pressure measuring tube is equal to the pressure in the cylinder, that is, P 上 = P The outlet of the lower pressure measuring tube is placed in a mixture of steel balls, raw coal particles and fine coal powder. There is a large enough gap between the steel balls and the raw coal particles, which will not cause additional resistance to the lower pressure measuring tube. However, the fine coal powder will cause additional resistance to the lower pressure measuring tube, that is, the fine coal powder plays a role in Fig. 9 When the filling height of the gap by fine coal powder exceeds the outlet of the lower pressure measuring tube, the pressure in the lower pressure measuring tube is equal to the pressure in the cylinder plus the resistance generated by the fine coal powder, that is, P 下 =P 筒 +P 粉 The resistance generated by the fine coal powder is proportional to the depth of the fine coal powder buried below the outlet of the pressure measuring tube, that is, P 粉=a*h, a is a constant, h is the depth of the fine coal powder buried through the outlet of the lower pressure measuring tube, and also represents the position of the fine coal powder in the cylinder, that is, the material level.

[0072] The pressure difference between the lower and upper pressure measuring tubes ΔP=P 下 -P 上 =a*h, because a is a constant, ΔP is usually also called material level. By installing a differential pressure transmitter on the external pipeline, ΔP can be measured in real time to determine the position of fine coal powder in the cylinder. Within a certain range, the amount of fine coal powder in the cylinder is monotonically corresponding to the total amount of coal in the cylinder, so the measured pressure difference ΔP is used to determine the amount of coal in the cylinder, and the coal feeding amount of the coal feeder is controlled in real time based on ΔP, so that the total amount of coal in the cylinder is always within a reasonable range.

[0073] The condition for ensuring the normal operation of the pressure differential level control system is that the lower pressure differential pipeline is inserted into the fine coal powder layer. The existing technology usually achieves this by reducing the amount of steel balls in the cylinder. As the amount of steel balls in the cylinder decreases, the total amount of the mixture of steel balls, raw coal particles and fine coal powder also decreases. When the pressure differential pipeline is so low that it cannot be inserted into the fine coal powder layer, the pressure differential level control system becomes ineffective.

[0074] Therefore, in this embodiment, by installing an annular bin in the cylinder, the annular bin occupies a part of the space in the cylinder, which can reduce the effective volume in the cylinder. By reducing the effective volume of the cylinder, the steel ball loading coefficient can be increased.

[0075] The ball adding device of the double-inlet and double-outlet steel ball coal mill is at one end, and steel balls are always added from one end, which will cause the amount of steel balls in the chamber on the ball adding side to be greater than that on the other side. Raw coal enters the cylinder from both ends of the cylinder, and sometimes the amount of coal entering the two ends is not equal. The amount of raw coal in the chamber on the end with a large amount of coal entering is greater than that on the other end. By setting the annular groove in the second ring chamber, the side with a high ball position and coal position can flow to the side with a low ball position, ensuring the balance of the ball position and coal position in the first chamber and the second chamber. The setting of the wedge block can prevent the steel balls in the groove from rotating with the cylinder.

[0076] In this embodiment, when the volume of the steel balls in the cylinder remains unchanged or decreases, the effective volume in the cylinder is reduced by setting an annular bin, so that the steel ball loading coefficient can be improved; the design of the groove and the wedge block can ensure the balance of the ball position and the coal position in the first chamber and the second chamber, and the first inclined surface and the second inclined surface can raise the filling height of the steel balls, raw coal particles and fine coal powder mixture, so that the steel ball loading coefficient is closer to the optimal steel ball loading coefficient, and the failed pressure difference material level control system can be restored to normal.

[0077] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0078] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cylinder structure for a ball coal mill, characterized in that: It comprises a cylinder (5) with both ends closed, a transmission shaft and an annular bin. A ball filling port is provided at one end of the cylinder (5), and coal filling ports are provided at both ends thereof; the transmission shaft is coaxially located in the inner cavity of the cylinder (5), passes through both ends thereof and is fixedly connected thereto; the annular outer wall of the annular bin is bolted to the middle inner wall of the cylinder (5) to divide the inner cavity of the cylinder (5) into two first chambers (51) and second chambers (52) of equal volume; the annular inner wall of the annular bin is sleeved and fixed on the transmission shaft; a notch is provided in the annular inner wall of the annular bin relative to the transmission shaft to connect the first chamber (51) and the second chamber (52) to balance the material level.

2. The cylinder structure for a ball coal mill according to claim 1, characterized in that: The annular bin comprises a first annular bin body (1) and a second annular bin body (2); The first ring warehouse body (1) comprises an outer ring surface 1 and two side ring surfaces 1, one end of the two side ring surfaces 1 are respectively connected to the two ends of the outer ring surface 1 along its axial direction, and the other end is inclined toward the central axis of the first ring warehouse body (1) and close to each other to form a first inclined surface (11), and the side of the two first inclined surfaces (11) corresponding to the central axis of the first ring warehouse body (1) is the inner ring side of the first ring warehouse body (1); The second ring chamber body (2) comprises an outer ring surface 2, two side ring surfaces 2 and an inner ring surface, wherein the outer ring surface 2 is coaxially fitted and fixed on the inner ring side of the first ring chamber body (1); one end of the two side ring surfaces 2 are respectively connected to the two ends of the outer ring surface 2 along its axial direction, and the other end is respectively connected to the two ends of the inner ring surface along its axial direction, and the other ends of the two side ring surfaces 2 are inclined toward the central axis of the second ring chamber body (2) and in a direction close to each other to form a second inclined surface (21).

3. The cylinder structure for a ball coal mill according to claim 2, characterized in that: The inclination angle of the second inclined surface (21) is greater than the inclination angle of the first inclined surface (11).

4. The cylinder structure for a ball coal mill according to claim 2, characterized in that: It also includes a wedge block (3), and a plurality of grooves (22) are formed on the inner ring surface of the second ring chamber body (2); the number of the wedge blocks (3) is multiple, and the multiple wedge blocks (3) are fixed one by one on the groove side walls of the multiple grooves (22) facing the rotation direction of the cylinder (5).

5. The cylinder structure for a ball coal mill according to claim 3, characterized in that: A wear-resistant layer is fixed on both the first inclined surface (11) and the second inclined surface (21), and the wear-resistant layer is formed by splicing a plurality of first lining plates (4) or by bimetallic surfacing.

6. The cylinder structure for a ball coal mill according to claim 5, characterized in that: A plurality of bolt holes are provided on the first inclined surface (11) and the second inclined surface (21); the first lining plate (4) is a fan-shaped structure; a convex ridge (41) is fixed on a side panel away from the first inclined surface (11) or the second inclined surface (21); countersunk holes (42) corresponding to the bolt holes are provided on the convex ridge (41); the threaded ends of the fastening bolts pass through the countersunk holes (42) and the bolt holes in sequence to fasten the first lining plate (4) to the first inclined surface (11) or the second inclined surface (21).

7. The cylinder structure for a ball coal mill according to claim 6, characterized in that: The wedge block (3) is an internal hollow structure, and the angle φ between the two wedge-shaped inclined surfaces (31) of the wedge block (3) is 40° to 60°.

8. The cylinder structure for a ball coal mill according to claim 7, characterized in that: The groove (22) has a groove depth of 150 to 300 mm and is greater than the outer diameter of the steel ball.

9. The cylinder structure for a ball coal mill according to claim 2, characterized in that: The outer ring surface of the first ring chamber body (1) is bolted to the middle inner wall of the cylinder body (5); the inner ring surface of the second ring chamber body (2) is tightly fitted with the outer wall of the transmission shaft.

10. The cylinder structure for a ball coal mill according to claim 1, characterized in that: A second lining plate (6) is bolted to the inner wall of the cylinder (5).

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