Low-resistance grinding roller sealing system device of medium-speed coal mill in thermal power plant

Abstract

The invention relates to a low-resistance grinding roller sealing system device of a medium-speed coal mill in a thermal power plant. The low-resistance grinding roller sealing system device comprises a hydraulic pull rod, three grinding rollers arranged in the coal mill and a hollow triangular pressure frame, the tops of the three grinding rollers are connected through the triangular pressure frame; the bottom of each vertex of the triangular pressure frame is fixedly connected with the hydraulic pull rod; each vertex of the triangular pressure frame is provided with an air inlet channel communicated with the interior of the triangular pressure frame, and the other end of each air inlet channel extends out of the coal mill and is connected with an external air source; each edge of the triangular pressure frame is provided with an air supply channel communicated with the interior of the triangular pressure frame, and the other end of the air supply channel extends into a bearing cavity of the adjacent grinding roller; when the hydraulic pull rod controls the triangular pressure frame to ascend and descend, sealing air sequentially flows through the air inlet channel, the interior of the triangular pressure frame and the air supply channel and then enters the bearing cavity. The sealing air conveying system and the hydraulic loading system are combined, the distance for conveying sealing air into the grinding roller is shortened, and meanwhile the influence on an air powder flow field in the coal mill in the sealing air conveying process can be avoided to the maximum extent.

Description

Technical Field

[0001] The invention relates to a low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant, belonging to the technical field of coal mills. Background Art

[0002] For example, a bowl-type medium-speed coal mill tire-type grinding roller device disclosed in a Chinese patent with announcement number CN117696182A, the grinding part of the existing medium-speed roller ring type coal mill is usually composed of a rotating grinding ring and three grinding rollers, and the force generated by the hydraulic loading system acts on the grinding rollers through an equilateral triangle structure hollow pressure frame to improve the grinding efficiency. The small-size coal powder after grinding is easily invaded into the grinding rollers and causes them to wear during the process of being carried out of the coal mill by the flowing dry high-temperature gas. Therefore, it is necessary to set an annular air duct and a vertical sealing air duct in the center of the coal mill to introduce nitrogen and other gases as grinding roller sealing wind into the grinding roller bearing chamber, as a conveying sealing air system (such as) used independently from the hydraulic loading system. Figure 1 As shown in the figure, the conveying sealing air system is easily damaged by the long-term sweeping of the air-powder mixture in the mill due to the structural characteristics of the mill. At the same time, it affects the smoothness of the air-powder flow field inside the coal mill and increases the resistance inside the mill.

[0003] A Chinese patent with announcement number CN207981315U discloses a grinding roller sealing system for a coal mill, including a low-pressure nitrogen sealing ring pipe, a connector, and a sealing metal hose. The low-pressure nitrogen sealing ring pipe is connected to the sealing metal hose through a plug-in connector, and the nitrogen sealing ring pipe is arranged outside the coal mill; the sealing metal hose is arranged on the grinding roller. Although the annular pipeline is moved outside the coal mill, the vertical sealing metal hose arranged in the center of the coal mill still cannot avoid being washed by coal powder, and cannot avoid disturbing the wind-powder flow field. Summary of the invention

[0004] In order to overcome the above problems, the present invention provides a low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant, which combines the sealing air conveying system with the hydraulic loading system and shortens the distance for conveying the sealing air to the inside of the grinding roller. At the same time, it can avoid the influence of the sealing air conveying process on the wind and powder flow field in the coal mill to the greatest extent.

[0005] The technical solution of the present invention is as follows:

[0006] A low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant comprises a hydraulic pull rod, three grinding rollers placed inside the coal mill, and a hollow triangular pressure frame; the tops of the three grinding rollers are connected through the triangular pressure frame; the bottom of each vertex of the triangular pressure frame is fixedly connected to the hydraulic pull rod; each vertex of the triangular pressure frame is provided with an air intake channel intersecting with the interior thereof, and the other end of the air intake channel extends to the outside of the coal mill and is connected to an external air source; each side of the triangular pressure frame is provided with an air supply channel intersecting with the interior thereof, and the other end of the air supply channel extends to the bearing chamber of the adjacent grinding roller; when the hydraulic pull rod controls the lifting and lowering of the triangular pressure frame, the sealing wind flows through the air intake channel, the interior of the triangular pressure frame, the air supply channel in sequence, and then enters the bearing chamber.

[0007] Furthermore, the air intake channel includes a connecting channel and an external sealed air duct arranged parallel to the hydraulic pull rod; the top of each vertex of the triangular pressure frame forms a connecting channel that is perpendicular to the frame and internally connected, and the other end of the connecting channel is fixedly connected to the external sealed air duct, and the other end of the external sealed air duct extends upward to the outside of the coal mill.

[0008] Furthermore, each of the air supply channels includes a flexible sealing duct and a vertical sealed air duct; each of the bearing chambers is fixedly connected to the vertical sealed air duct that is communicated with the interior thereof, and the other end of the vertical sealed air duct is fixedly connected to the edge of the adjacent triangular pressure frame through the flexible sealing duct.

[0009] Furthermore, the connecting channel and the external sealed air duct are connected via a non-metallic expansion joint; both ends of each non-metallic expansion joint are fixedly connected to the adjacent ends of the connecting channel and the external sealed air duct via a plurality of clamping bolts.

[0010] Furthermore, two ends of the flexible sealed duct are fixedly connected to the adjacent sides of the triangular pressure frame and the end of the vertical sealed air duct through flanges.

[0011] Furthermore, a through hole which is larger at the top and smaller at the bottom is provided at the bottom of each vertex of the triangular pressure frame, and a sealing member which matches the shape of the through hole is provided in the through hole, and the lower part of the seal is fixedly connected to the hydraulic pull rod corresponding to its position by a pull rod fixing bolt; a sealing top plate which covers the top surface of each seal is provided above the seal, and the sealing top plate is placed in the triangular pressure frame and fixedly connected to its bottom.

[0012] Furthermore, the periphery of each of the sealing top plates is fixedly connected to the bottom of the triangular pressure frame by a plurality of bolts.

[0013] Furthermore, the lower part of the seal is placed outside the triangular pressure frame, and the bottom of the seal is concave to form a groove for accommodating the end of the hydraulic tie rod; the tie rod fixing bolt passes through the adjacent groove and the end of the hydraulic tie rod in sequence and is locked with a nut.

[0014] The present invention has the following beneficial effects:

[0015] 1. The present invention combines the hydraulic loading system of the coal mill with the sealed air conveying system, so that the sealed air enters the inside of the triangular pressure frame through the air inlet channel arranged at the vertex of the triangular pressure frame, and is introduced into the bearing chamber of the grinding roller under the cooperation of the flexible sealing duct and the vertical sealed air duct, thereby improving the sealing performance of the grinding roller on the basis of shortening the sealed air conveying distance and reducing the wear of the grinding roller and the sealed air conveying system.

[0016] 2. The triangular pressure frame of the present invention serves as a part of the sealed air conveying system, and the tops of each vertex are used to connect to the air inlet channel, and the bottoms of each vertex are connected to the hydraulic pull rods corresponding to their positions, so that the hydraulic loading system is combined with the sealed air conveying system. When the hydraulic pull rods control the lifting of the triangular pressure frame, the sealed air is conveyed to the grinding roller through a shorter distance by using the hollow triangular pressure frame, which can avoid the influence of the sealed air conveying system part placed inside the coal mill on the smoothness of the wind-powder flow field to the greatest extent.

[0017] 3. The present invention arranges the external sealed air duct, the connecting pipe and the hydraulic pull rod in parallel in the air intake channel, and connects the adjacent external sealed air duct and the connecting pipe through a non-metallic expansion joint to compensate for the changed distance between the external sealed air duct and the connecting pipe when the hydraulic pull rod controls the lifting and lowering of the triangular pressure frame, so that the air intake channel can maintain its function of conveying sealed air and the sealing performance is not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the grinding roller sealed air conveying system in the prior art.

[0019] Figure 2 It is a schematic diagram of the overall structure of the present invention.

[0020] Figure 3 for Figure 2 A local enlarged schematic diagram of point A.

[0021] Figure 4 It is a schematic diagram of the connection relationship between the air supply channel, the pressure frame and the adjacent bearing chamber.

[0022] The reference numerals in the figure are as follows:

[0023] 1. Hydraulic pull rod; 2. Grinding roller; 21. Bearing chamber; 3. Triangular pressure frame; 4. Air inlet channel; 41. Connecting pipe; 42. External sealed air duct; 43. Non-metallic expansion joint; 5. Air supply channel; 51. Flexible sealed pipe; 52. Vertical sealed air duct; 6. Holding bolt; 7. Flange; 8. Seal; 81. Groove; 9. Pull rod fixing bolt; 10. Sealing top plate; 11. Bolt; 12. Nut; 13. Annular air duct; 14. Vertical sealed air duct. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] See also Figure 1-4 A low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant comprises three grinding rollers 2 placed inside the coal mill. The tops of the three grinding rollers 2 are connected by a hollow triangular pressure frame 3. The bottoms of the vertices of the triangular pressure frame 3 are fixedly connected with hydraulic pull rods 1. When the medium-speed coal mill is working, the three grinding rollers 2 rotate and are lifted and lowered under the action of the hydraulic pull rods 1, thereby controlling the grinding rollers 2 to grind. At the same time, sealing air is introduced into the bearing chamber 21 of the grinding roller 2 through an external sealing air duct 42, so that the grinding roller 2 can prevent coal powder with a small particle size from entering the grinding roller 2 and damaging the bearing by spraying sealing air.

[0026] Furthermore, a vertical sealed air duct 52 which is connected to the interior of the bearing chamber 21 of each grinding roller 2 is fixedly connected, and the vertical sealed air duct 52 extends to the outside of the bearing chamber 21, and is connected to the interior of the triangular pressure frame 3 through the flexible sealed duct 51, and each vertex of the triangular pressure frame 3 is provided with an external sealed air duct 42 which is connected to the interior of the bearing chamber 21; when the medium-speed coal mill is working, coal powder with a particle size that meets the requirements will be blown up and taken out of the coal mill by the high-temperature dry gas, so it is necessary to reduce the resistance of the air flow inside the coal mill to keep the coal powder movement trajectory unobstructed, and set the external sealed air duct 42 at each vertex of the triangular pressure frame 3, and use the hollow structure of the triangular pressure frame 3 to make the sealed air flow from each vertex of the pressure frame to the interior of the pressure frame in turn, and finally be introduced into the grinding roller 2 through the cooperation of the flexible sealed duct 51 and the adjacent vertical sealed air duct 52, which can avoid its influence on the movement trajectory of the coal powder to the greatest extent, and at the same time reduce the sticking phenomenon of the coal powder and improve the output of the coal mill.

[0027] The two ends of each flexible sealed duct 51 are fixedly connected to the adjacent side of the triangular pressure frame 3 and the end of the vertical sealed air duct 52 through flanges 7 .

[0028] Furthermore, a connecting pipe 41 is formed at the top of each vertex of the triangular pressure frame 3, which is perpendicular to the vertex and internally connected thereto. The other end of the connecting pipe 41 is fixedly connected to the non-metallic expansion joint 43, and the other end of the non-metallic expansion joint 43 is fixedly connected to an external sealed air duct 42. The other end of the external sealed air duct 42 extends upward to the outside of the coal mill; the interiors of the external sealed air duct 42, the non-metallic expansion joint 43, the connecting pipe 41, the triangular pressure frame 3, the flexible sealed pipe 51, and the vertical sealed air duct 52 are all interconnected to transport the external sealed air to the bearing chamber 21 of each grinding roller 2. At the same time, the non-metallic expansion joint 43 can provide a movable surplus for the increase or shortening of the distance between the external sealed air duct 42 and the connecting pipe 41 when the hydraulic pull rod 1 controls the lifting and lowering of the triangular pressure frame 3, so as to ensure that the sealed air delivery is not affected; wherein, the two ends of the non-metallic expansion joint 43 are respectively fixedly connected to the adjacent ends of the external sealed air duct 42 and the ends of the connecting pipe 41 by tightening bolts 6.

[0029] Furthermore, a through hole with a larger top and a smaller bottom is provided at the bottom of each vertex of the triangular pressure frame 3, and a sealing member 8 matching the shape of the through hole is provided in the through hole, and the lower part of the sealing member 8 is fixedly connected to the hydraulic pull rod 1 corresponding to its position through a pull rod fixing bolt 9; a sealing top plate 10 covering the top surface of each sealing member 8 is provided above the sealing member 8, and the sealing top plate 10 is placed in the triangular pressure frame 3 and fixedly connected to the bottom thereof, wherein the periphery of the sealing top plate 10 is fastened to the bottom of the triangular pressure frame 3 by a plurality of bolts 11; when the coal mill is working, the hydraulic pull rod 1 is driven to descend, generating a pulling force on the sealing member 8 connected thereto, and the through hole is used to tighten the sealing member 8 to the bottom thereof. The cooperation of the seal 8 with a larger upper part and a smaller lower part and the through hole causes the triangular pressure frame 3 to move downward, thereby causing the grinding roller 2 to perform a grinding operation. The seal 8 may be in the shape of an inverted truncated cone or a hemispherical shape, wherein a hemispherical shape is preferred to ensure that the outer periphery of the seal 8 can still maintain a close fit with the through hole under the condition of wear, thereby ensuring the sealing of the bottom of the triangular pressure frame 3; when the grinding is stopped, the hydraulic pull rod 1 is driven to rise, at which time the sealing top plate 10 limits the seal 8 from being pushed away from the through hole by the hydraulic pull rod 1, and the hydraulic pull rod 1 lifts the sealing top plate 10 through the seal 8 connected thereto, thereby driving the triangular pressure frame 3 to move upward to lift the grinding roller 2.

[0030] Furthermore, the lower part of the seal 8 is placed outside the triangular pressure frame 3, and the bottom of the seal 8 is concave to form a groove 81 for accommodating the end of the hydraulic tie rod 1; when in use, the hydraulic tie rod 1 corresponding to the vertex position of the triangular pressure frame 3 is inserted into the adjacent groove 81, and each corresponding hydraulic tie rod 1 is fastened to the groove 81 by a tie rod fixing bolt 9, and the tie rod fixing bolt 9 passes through the groove 81 and the hydraulic tie rod 1 in turn and is locked with the nut 12.

[0031] Working principle of the present invention:

[0032] See also Figure 1-4 When the coal mill is working, the hydraulic pull rod 1 is driven to descend, driving the triangular pressure frame 3 to press down, so that the grinding roller 2 connected to the triangular pressure frame 3 performs a grinding operation. At the same time, the sealing air transported by the external air source flows through the external sealing air duct 42, the non-metallic expansion joint 43, the connecting pipe 41, the triangular pressure frame 3, the flexible sealing pipe 51, and the vertical sealing air duct 52 in sequence, and is then introduced into the bearing chamber 21 of each grinding roller 2 to improve the sealing performance of the grinding roller 2; when the coal mill stops working, the hydraulic pull rod 1 is driven to rise, driving the hydraulic pull rod 1 to rise, and lifting the sealing top plate 10 through the sealing member 8 connected thereto, thereby driving the triangular pressure frame 3 to move upward to lift the grinding roller 2.

[0033] In the process of controlling the triangular pressure frame 3 to rise or fall by the hydraulic pull rod 1 , the non-metallic expansion joint 43 is used to compensate for the increased or shortened conveying distance between the external sealed air duct 42 and its adjacent connecting duct 41 .

[0034] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant, comprising a hydraulic pull rod (1), three grinding rollers (2) arranged inside the coal mill, and a hollow triangular pressure frame (3); the tops of the three grinding rollers (2) are connected through the triangular pressure frame (3); the bottom of each vertex of the triangular pressure frame (3) is fixedly connected to the hydraulic pull rod (1), characterized in that: Each vertex of the triangular pressure frame (3) is provided with an air intake channel (4) interpenetrating with the interior thereof, and the other end of the air intake channel (4) extends to the outside of the coal mill and is connected to an external air source; each side of the triangular pressure frame (3) is provided with an air supply channel (5) interpenetrating with the interior thereof, and the other end of the air supply channel (5) extends to the bearing chamber (21) of the adjacent grinding roller (2); when the hydraulic pull rod (1) controls the lifting and lowering of the triangular pressure frame (3), the sealing air flows through the air intake channel (4), the interior of the triangular pressure frame (3), the air supply channel (5) in sequence, and then enters the bearing chamber (21).

2. A low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant according to claim 1, characterized in that: The air inlet passage (4) comprises a connecting pipe (41) and an external sealed air duct (42) arranged in parallel with the hydraulic pull rod (1); the top of each vertex of the triangular pressure frame (3) forms a connecting pipe (41) which is perpendicular to the triangular pressure frame and is internally connected thereto, and the other end of the connecting pipe (41) is fixedly connected to the external sealed air duct (42), and the other end of the external sealed air duct (42) extends upward to the outside of the coal mill.

3. The low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant according to claim 1, characterized in that: Each of the air supply channels (5) comprises a flexible sealing duct (51) and a vertical sealing air duct (52); each of the bearing chambers (21) is fixedly connected with the vertical sealing air duct (52) which is in communication with the interior thereof, and the other end of the vertical sealing air duct (52) is fixedly connected to the edge of the adjacent triangular pressure frame (3) via the flexible sealing duct (51).

4. A low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant according to claim 2, characterized in that: The connecting pipe (41) and the external sealed air pipe (42) are connected via a non-metallic expansion joint (43); the two ends of each non-metallic expansion joint (43) are fixedly connected to the adjacent ends of the connecting pipe (41) and the external sealed air pipe (42) via a plurality of clamping bolts (6).

5. The low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant according to claim 3, characterized in that: The two ends of the flexible sealed duct (51) are respectively fixedly connected to the edges of the adjacent triangular pressure frame (3) and the end of the vertical sealed air duct (52) through flanges (7).

6. A low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant according to claim 4 or 5, characterized in that: A through hole with a larger top and a smaller bottom is provided at the bottom of each vertex of the triangular pressure frame (3), and a sealing member (8) matching the shape of the through hole is provided in the through hole. The lower part of the sealing member (8) is fixedly connected to the hydraulic pull rod (1) corresponding to its position via a pull rod fixing bolt (9); a sealing top plate (10) covering the top surface of each sealing member (8) is provided above the sealing member (8), and the sealing top plate (10) is placed in the triangular pressure frame (3) and fixedly connected to the bottom thereof.

7. A low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant according to claim 6, characterized in that: The periphery of each sealing top plate (10) is fixedly connected to the bottom of the triangular pressure frame (3) via a plurality of bolts (11).

8. The low-resistance grinding roller sealing system device for a medium-speed coal mill in a thermal power plant according to claim 7, characterized in that: The lower part of the sealing member (8) is placed outside the triangular pressure frame (3), and the bottom of the sealing member (8) is concave to form a groove (81) for accommodating the end of the hydraulic tie rod (1); the tie rod fixing bolt (9) passes through the adjacent groove (81) and the end of the hydraulic tie rod (1) in sequence and is then locked with the nut (12).

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