A coal mill main shaft sealing structure

Abstract

The utility model relates to the technical field of coal mill seals, and discloses a coal mill main shaft sealing structure, including a grinding bowl main shaft, a side machine body bottom plate, a flange structure, an elastic seal and a limiter, wherein the grinding bowl main shaft is arranged through the side machine body bottom plate, and the grinding bowl main shaft and the side machine body bottom plate are gap-matched; the flange structure is fixed on the lower side of the side machine body bottom plate, the flange structure and the side machine body bottom plate are arranged in parallel and spaced to form an annular space, the limiter is fixedly installed in the annular space, and the limiter is axially pressed with the flange structure and the side machine body bottom plate respectively; the elastic seal is arranged in the annular space, the flange structure and the side machine body bottom plate are axially pressed with the elastic seal respectively, and the elastic seal is circumferentially sealed with the outer surface of the grinding bowl main shaft. The gap between the grinding bowl main shaft and the side machine body bottom plate can be eliminated by the radial expansion deformation of the elastic seal, and the fly ash and hot air inside the coal mill can be prevented from leaking outward from the gap to cause erosion of the sealing structure.

Description

Technical Field

[0001] The utility model relates to the technical field of coal mill seals, in particular to a main shaft seal structure of a coal mill. Background Art

[0002] Coal mill is a common industrial production equipment, the main function of which is to break coal into powder. Medium-speed coal mill is widely used in coal-fired boilers due to its compact structure and low energy consumption.

[0003] Take HP863 medium speed coal mill as an example: Figure 1 As shown, the grinding bowl base of the coal mill is provided with a main shaft 1a, which passes through the side body bottom plate 2a and is fixedly connected to the output shaft of the reducer. A gap 10a of about 8mm is reserved at the position where the grinding bowl base passes through the side body. This gap 10a is designed with a copper sheet sealing group 3a, which is assembled from three or more layers of copper sheets. The copper sheets are separated by pads and axially pressed on the lower side of the side body bottom plate 2a to form a radial sealing structure centered on the main shaft 1a. The gap between the copper sheet and the main shaft 1a is adjusted to be within the range of 0.5mm to 0.75mm.

[0004] There is a certain gap between the main shaft and the copper sheet of the existing coal mill. The fly ash and hot air inside the coal mill leak out from the gap and cause erosion to the sealing structure, and the accumulation of particles at the seal further increases the wear. In addition, the coal mill operates in poor conditions, and the grinding bowl will cause intermittent swing and slight tilt of the main shaft due to unbalanced load, which seriously affects the abnormal wear, loss of roundness and deformation of the copper sheet seal group. Utility Model Content

[0005] The technical problem to be solved by the utility model is that the fly ash and hot air inside the existing coal mill leak out from the gaps to scour the sealing structure, and the particles accumulate at the sealing point to further increase the wear; and the main shaft will intermittently swing, slightly tilt, etc., seriously affecting the abnormal wear, out-of-roundness and deformation of the copper sheet sealing group.

[0006] In order to solve the above technical problems, the utility model provides a technical solution for the main shaft sealing structure of a coal mill:

[0007] The coal mill main shaft sealing structure comprises a grinding bowl main shaft, a side machine body bottom plate, a flange structure, an elastic sealing member and a stopper. The grinding bowl main shaft is arranged through the side machine body bottom plate, and the grinding bowl main shaft and the side machine body bottom plate are clearance-matched.

[0008] The flange structure is fixedly connected to the lower side of the side body bottom plate, the flange structure and the side body bottom plate are arranged in parallel and spaced apart to form an annular space, the limiter is fixedly installed in the annular space, and the limiter is respectively press-fitted with the flange structure and the side body bottom plate along the axial direction of the grinding bowl spindle;

[0009] The elastic seal is circumferentially arranged in the annular space, the flange structure and the side body bottom plate are respectively axially extruded and matched with the elastic seal, and the elastic seal is circumferentially sealed and matched with the outer surface of the grinding bowl spindle.

[0010] Furthermore, the thickness of the elastic seal is greater than the maximum radial distance between the grinding bowl spindle and the bottom plate of the side body, and the limit member is radially stopped in cooperation with the elastic seal.

[0011] Furthermore, a grease groove is provided on the inner side of the elastic seal, and the grease groove is arranged to extend along the circumference of the grinding bowl spindle, and the interior of the grease groove is used to fill with lubricating grease.

[0012] Furthermore, two grease grooves are arranged in parallel and at intervals, and the depth of the grease grooves is less than half of the thickness of the elastic sealing element.

[0013] Furthermore, the elastic seal is a fluororubber sealing strip, at least two of the elastic seals are provided, both ends of the elastic seal are provided with oblique openings, and the oblique openings of two adjacent elastic seals are overlapped and matched.

[0014] Furthermore, the width of the elastic seal is 90 mm, the thickness of the elastic seal is 25 mm, the depth and width of the grease groove are both 10 mm, and the axial dimension of the limiter is 85 mm.

[0015] Furthermore, a fixing hole is opened on the bottom plate of the side body, a fastening bolt is installed through the flange structure, and the fastening bolt is threadedly matched with the fixing hole.

[0016] Furthermore, the flange structure includes a plurality of arc-shaped flanges, and the plurality of arc-shaped flanges are spliced ​​and combined to form a flange structure surrounding the grinding bowl spindle.

[0017] Furthermore, a plurality of the limiting members are circumferentially spaced apart in the annular space, and the limiting members are angle irons, and the length direction of the angle irons is along the axial direction of the grinding bowl spindle.

[0018] Compared with the prior art, the utility model provides a coal mill main shaft sealing structure, which has the following beneficial effects: the coal mill main shaft sealing structure adopts a design form of a grinding bowl main shaft, a side machine body bottom plate, a flange structure, an elastic sealing member and a limit member, wherein the grinding bowl main shaft is penetrated and arranged in the side machine body bottom plate, and the grinding bowl main shaft and the side machine body bottom plate are clearance-matched, and during the rotation of the grinding bowl main shaft, the reserved clearance L avoids friction and wear between the grinding bowl main shaft and the side machine body bottom plate, thereby ensuring the movement accuracy and reliability of the grinding bowl main shaft.

[0019] The flange structure is fixedly connected to the lower side of the side body bottom plate. The flange structure and the side body bottom plate are arranged in parallel and spaced apart to form an annular space. The limiter is fixedly installed in the annular space. The limiter is respectively axially pressed with the flange structure and the side body bottom plate to effectively limit the relative position of the flange structure and the side body bottom plate, thereby ensuring the accuracy and consistency of the axial size of the annular space, thereby ensuring that the elastic seal is subjected to balanced axial extrusion force in the annular space.

[0020] Moreover, the elastic seal is arranged in an annular space, and the flange structure and the side body bottom plate respectively exert axial extrusion on the elastic seal, and the elastic seal is subjected to axial extrusion and converted into radial expansion deformation, and the elastic seal cooperates with the outer surface of the grinding bowl main shaft in a circumferential seal. The elastic seal is arranged around the outer surface of the grinding bowl main shaft, and not only fully eliminates the gap L between the grinding bowl main shaft and the side body bottom plate through its own expansion deformation, but also the elastic seal contacts the lower surface of the side body bottom plate through extrusion to form a seal.

[0021] Its function is not only to prevent the fly ash and hot air inside the coal mill from leaking out from the gap L and eroding the sealing structure, but also to prevent the accumulation of particles at the seal to further increase wear. Since the elastic seal does not rotate with the grinding bowl spindle, even if the grinding bowl spindle has intermittent swings or slight tilts, the expansion and deformation of the elastic seal can compensate for the change in the gap, ensuring the reliability of the sealing structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a cross-sectional schematic diagram of a copper sheet seal assembly of an existing coal mill in the background technology;

[0023] Figure 2 It is a cross-sectional schematic diagram of the main shaft sealing structure of the coal mill in the embodiment of the utility model;

[0024] Figure 3 yes Figure 2 A partial enlarged view of the main shaft seal structure of the medium coal mill at point A;

[0025] Figure 4 It is a cross-sectional schematic diagram of the elastic sealing member in the embodiment of the utility model;

[0026] Figure 1 Middle: 1a-spindle, 10a-gap, 2a-side machine body bottom plate, 3a-copper sheet sealing group;

[0027] Figures 2 to 4 In: 1- grinding bowl spindle, 2- side body bottom plate, 20- annular space, 3- flange structure, 4- elastic seal, 40- grease groove, 5- limiter, 6- fastening bolt. DETAILED DESCRIPTION

[0028] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0029] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like used in the present invention to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] like Figures 2 to 4As shown, a coal mill main shaft sealing structure of an embodiment of the utility model includes a grinding bowl main shaft 1, a side body bottom plate 2, a flange structure 3, an elastic seal 4 and a limiter 5. The grinding bowl main shaft 1 is arranged through the side body bottom plate 2, and the grinding bowl main shaft 1 and the side body bottom plate 2 are clearance-matched; the flange structure 3 is fixedly connected to the lower side of the side body bottom plate 2, and the flange structure 3 and the side body bottom plate 2 are arranged in parallel and spaced apart to form an annular space 20.

[0033] The limit member 5 is fixedly installed in the annular space 20, and the limit member 5 is press-fitted with the flange structure 3 and the side body bottom plate 2 along the axial direction of the grinding bowl spindle 1; the elastic seal 4 is circumferentially arranged in the annular space 20, and the flange structure 3 and the side body bottom plate 2 are axially extruded and fitted with the elastic seal 4, and the elastic seal 4 is circumferentially sealed with the outer surface of the grinding bowl spindle 1.

[0034] The coal mill main shaft sealing structure adopts a design form of a grinding bowl main shaft 1, a side body bottom plate 2, a flange structure 3, an elastic seal 4 and a limiter 5, wherein the grinding bowl main shaft 1 is arranged through the side body bottom plate 2, and the grinding bowl main shaft 1 and the side body bottom plate 2 are clearance-matched. During the rotation of the grinding bowl main shaft 1, the reserved gap L avoids friction and wear between the grinding bowl main shaft 1 and the side body bottom plate 2, thereby ensuring the movement accuracy and reliability of the grinding bowl main shaft 1.

[0035] The flange structure 3 is fixedly connected to the lower side of the side body bottom plate 2. The flange structure 3 and the side body bottom plate 2 are arranged in parallel and spaced apart to form an annular space 20. The limiting member 5 is fixedly installed in the annular space 20. The limiting member 5 is axially pressed with the flange structure 3 and the side body bottom plate 2 respectively, thereby effectively limiting the relative position of the flange structure 3 and the side body bottom plate 2, ensuring the accuracy and consistency of the axial size of the annular space 20, thereby ensuring that the elastic seal 4 is subjected to a balanced axial extrusion force in the annular space 20.

[0036] Moreover, the elastic seal 4 is arranged in the annular space 20, and the flange structure 3 and the side body bottom plate 2 respectively exert axial extrusion on the elastic seal 4, and the elastic seal 4 is subjected to axial extrusion and converted into radial expansion deformation, and the elastic seal 4 is circumferentially sealed with the outer surface of the grinding bowl spindle 1. The elastic seal 4 is arranged around the outer surface of the grinding bowl spindle 1, and not only fully eliminates the gap L between the grinding bowl spindle 1 and the side body bottom plate 2 through its own expansion deformation, but also the elastic seal 4 is squeezed and contacted with the lower surface of the side body bottom plate 2 to form a seal.

[0037] Its function is not only to prevent the fly ash and hot air inside the coal mill from leaking outward from the gap L and eroding the sealing structure, but also to prevent the accumulation of particles at the seal to further increase wear. Since the elastic seal 4 does not rotate with the grinding bowl spindle 1, even if the grinding bowl spindle 1 has intermittent swings or slight tilts, the change in the gap can be compensated by the expansion and deformation of the elastic seal 4, ensuring the reliability of the sealing structure.

[0038] In this embodiment, the thickness T of the elastic seal 4 is greater than the maximum radial spacing between the grinding bowl spindle 1 and the side body bottom plate 2, and the limiter 5 cooperates with the elastic seal 4 to radially stop. Specifically, the average radial spacing L between the grinding bowl spindle 1 and the side body bottom plate 2 is 8mm, which can be understood as when the radial spacing on one side is 0, the radial spacing on the other side is 16mm, that is, the maximum radial spacing. The thickness T of the elastic seal 4 is designed to be 25mm to prevent the elastic seal 4 from being squeezed out of the annular space 20 due to the swing and tilt of the grinding bowl spindle 1. In addition, the width D of the elastic seal 4 is 90mm, the axial dimension of the limiter 5 is 85mm, the axial compression of the elastic seal 4 is 5mm, and the limiter 5 produces a radial stop effect on the elastic seal 4 to ensure that the elastic seal 4 is always tightly fitted on the outer surface of the grinding bowl spindle 1.

[0039] As a further preferred solution, a grease groove 40 is provided inside the elastic seal 4, and the grease groove 40 is arranged to extend along the circumference of the grinding bowl spindle 1. The inside of the grease groove 40 is used to fill with lubricating grease, which reduces the friction and wear of the grinding bowl spindle 1 on the elastic seal 4 and improves the durability and reliability of the elastic seal 4. Figure 4 As shown, two grease grooves 40 are arranged in parallel and spaced apart, and the depth of the grease groove 40 is less than half of the thickness T of the elastic sealing member 4. Specifically, the depth and width d of the grease groove 40 are both 10 mm.

[0040] In this embodiment, the elastic seal 4 is a fluororubber sealing strip, at least two elastic seals 4 are provided, both ends of the elastic seal 4 are provided with bevels, the bevels of two adjacent elastic seals 4 are overlapped, and the total length of at least two elastic seals 4 after overlap is equal to the outer circumference of the grinding bowl spindle 1. The fluororubber sealing strip has a temperature tolerance of more than 100°C, which can meet the temperature requirements of the coal mill interior not exceeding 90° and the average temperature of the grinding bowl spindle 1 of 52°C.

[0041] In addition, a fixing hole is provided on the side body bottom plate 2, and a fastening bolt 6 is installed through the flange structure 3, and the fastening bolt 6 is threadedly matched with the fixing hole. The flange structure 3 includes a plurality of arc-shaped flanges, and the plurality of arc-shaped flanges are spliced ​​and combined to form a flange structure 3 surrounding the grinding bowl main shaft 1. The plurality of arc-shaped flanges are fixed in sections to the lower side of the side body bottom plate 2 by fastening bolts 6, thereby forming a flange structure 3 surrounding the grinding bowl main shaft 1. Moreover, a plurality of limit members 5 are arranged at circumferential intervals in the annular space 20, and the limit members 5 are angle irons, the length direction of the angle irons is along the axial direction of the grinding bowl main shaft 1, and the inner angle of the angle irons faces the elastic seal 4. The axial distance of the annular space 20 is limited by a plurality of circumferentially spaced angle irons, and the elastic seal 4 is radially stopped to ensure a reliable sealing effect of the elastic seal 4.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A coal mill main shaft sealing structure, characterized in that: It includes a grinding bowl spindle, a side machine body bottom plate, a flange structure, an elastic seal and a stopper. The grinding bowl spindle is arranged through the side machine body bottom plate, and the grinding bowl spindle and the side machine body bottom plate are clearance-matched. The flange structure is fixedly connected to the lower side of the side body bottom plate, the flange structure and the side body bottom plate are arranged in parallel and spaced apart to form an annular space, the limiter is fixedly installed in the annular space, and the limiter is respectively press-fitted with the flange structure and the side body bottom plate along the axial direction of the grinding bowl spindle; The elastic seal is circumferentially arranged in the annular space, the flange structure and the side body bottom plate are respectively axially extruded and matched with the elastic seal, and the elastic seal is circumferentially sealed and matched with the outer surface of the grinding bowl spindle.

2. The coal mill main shaft sealing structure according to claim 1 is characterized in that: The thickness of the elastic seal is greater than the maximum radial distance between the grinding bowl spindle and the bottom plate of the side body, and the limiting member is radially stopped in cooperation with the elastic seal.

3. The coal mill main shaft sealing structure according to claim 2 is characterized in that: A grease groove is provided on the inner side of the elastic seal. The grease groove is arranged to extend along the circumference of the grinding bowl spindle. The interior of the grease groove is used to fill with lubricating grease.

4. The coal mill main shaft sealing structure according to claim 3 is characterized in that: Two grease grooves are arranged in parallel and at intervals, and the depth of the grease grooves is less than half of the thickness of the elastic sealing member.

5. The coal mill main shaft sealing structure according to claim 1 is characterized in that: The elastic seal is a fluororubber sealing strip. At least two elastic seals are provided. Both ends of the elastic seal are provided with oblique openings respectively. The oblique openings of two adjacent elastic seals are overlapped and matched.

6. The coal mill main shaft sealing structure according to claim 4 is characterized in that: The width of the elastic seal is 90 mm, the thickness of the elastic seal is 25 mm, the depth and width of the grease groove are both 10 mm, and the axial dimension of the limiter is 85 mm.

7. The coal mill main shaft sealing structure according to claim 1 is characterized in that: A fixing hole is provided on the bottom plate of the side body, a fastening bolt is installed through the flange structure, and the fastening bolt is threadedly matched with the fixing hole.

8. The coal mill main shaft sealing structure according to claim 1 is characterized in that: The flange structure includes a plurality of arc-shaped flanges, and the plurality of arc-shaped flanges are spliced ​​and combined to form a flange structure surrounding the grinding bowl spindle.

9. The coal mill main shaft sealing structure according to claim 1, characterized in that: A plurality of the limiting members are arranged in the annular space at intervals in the circumferential direction. The limiting members are angle irons, and the length direction of the angle irons is along the axial direction of the grinding bowl spindle.

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