Sealing device on pull rod of coal mill

Abstract

The utility model discloses a sealing device on a pull rod of a coal mill, and belongs to the technical field of pull rod axial dynamic sealing. The sealing device comprises a first sealing sheath, a second sealing sheath and a sealing box which are distributed up and down, wherein a first sealing ring is arranged in an inner cavity of the first sealing sheath, and a second sealing ring is arranged in an inner cavity of the second sealing sheath; one end of the second sealing sheath is in sealing connection with the first sealing sheath, and the second sealing sheath and the first sealing sheath can perform first relative movement in the radial direction; the other end of the second sealing sheath is connected with the sealing box in a sealing mode, the second sealing sheath and the sealing box can conduct radial second relative movement, and the first relative movement occurs after the second relative movement is in place. According to the utility model, two relative motions are carried out successively, so that even if the second sealing ring leaks due to extrusion deformation, the first sealing ring has a better moving space, the good sealing performance can be always kept, and the sealing effect of the whole device can be ensured.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of pull rod axial dynamic sealing, more particularly to a kind of sealing device on coal mill pull rod. BACKGROUND

[0002] Coal mill is the key equipment for breaking blocky materials such as coal into powder, and its main working process is as follows: the material falls on the grinding disc from the coal falling pipe, the driving device drives the main shaft to rotate to drive the grinding disc to rotate, and the material moves to the annular groove at the edge of the grinding disc under the action of centrifugal force; at this time, the pull rod drives the grinding roller to press down to crush the material; the crushed material is carried into the separator at the top of the coal mill by hot air, and under the action of the separator, coarse coal powder falls on the grinding disc for regrinding, and qualified fine coal powder is discharged with the airflow, which can be collected by the dust collection device to obtain the corresponding coal powder.

[0003] When the coal mill is working, in order to make the coal powder smoothly sent out of the coal mill with the airflow, the hot air will form a large air pressure inside the coal mill, which on the one hand dries the coal powder being sent out, and on the other hand sends the coal powder out of the coal powder outlet at the top of the coal mill, which will cause the coal powder to appear the phenomenon of finding a way out under the action of internal air pressure. Since the pull rod needs to move axially and also has a certain degree of radial swing during the actual working process of the coal mill, the sealing of the pull rod is relatively difficult. There must be a large gap between the pull rod and the pull rod box to ensure that the pull rod has enough swing space, which will cause the coal powder to drill out from the gap between the pull rod and the pull rod box under the action of air pressure, resulting in the leakage of coal powder and pollution of the environment. Therefore, the existing coal mill generally sets a pull rod upper sealing structure between the upper part of the pull rod box and the pull rod, and a pull rod lower sealing structure between the lower part of the pull rod box and the pull rod. The upper sealing structure and the lower sealing structure form a sealed air chamber through the pull rod box and the pull rod, and the coal mill blows sealing air into the sealed air chamber during work to compensate for the air pressure of the hot air in the coal mill, preventing the coal powder from leaking under the action of hot air.

[0004] For example, the patent CN214466072U discloses a protective sleeve and a pull rod upper sealing structure for coal mill. The application includes. The protective sleeve is used for protection of the pull rod upper sealing structure of the coal mill, and is in a cylindrical structure with two ends open and different sizes. One end with a smaller opening is a sleeve shaft opening, and the other end with a larger opening is a protection opening. The protective sleeve wall has a cutout from the sleeve shaft opening to the protection opening, through which the protective sleeve can be opened. The protective sleeve can more comprehensively shield the upper sealing. The pull rod upper sealing structure uses the above-mentioned protective sleeve, which can still more comprehensively shield the iron and carbon and metal particles falling with the hot air when the pull rod swings radially, reducing the external damage to the upper sealing during work and improving the sealing performance and sealing life of the sealing structure.

[0005] For example, in the patent CN205371631U, a sealing device for the pull rod of a coal mill is disclosed. The application includes a pull rod, a pull rod sealing air chamber, an upper seal and a lower seal. The upper seal is provided with an upper seal elastomer, and the outer side of the upper seal elastomer is provided with a conical surface, and the inner side is provided with a circular arc groove. The application sets a circular ring gap between the upper seal shell and the upper seal connecting plate, and sets a circular ring gap between the lower seal shell and the lower seal elastomer, so as to adapt to the up-down movement and radial swing of the pull rod, thereby solving the problem that the pull rod and the upper and lower seals are easily worn, and the phenomenon of coal powder leakage occurs.

[0006] The above-mentioned applications are all related to the technical improvement of the upper seal of the pull rod of a coal mill, and all have a certain improvement effect, but still have certain improvement space. For example, in the above two applications, the upper seal device adopts a radial movement structure, which will extrude the sealing ring inside when the radial movement is in place. The elastic compensation of the sealing ring will be greatly reduced after long-term extrusion or excessive extrusion, thereby increasing the risk of coal powder leakage. Practical new type content

[0007] 1. Problems to be solved

[0008] In view of at least some problems existing in the prior art, the present application provides a kind of upper seal device for the pull rod of a coal mill, which is to solve the problem that only one radial movement structure is used in the existing pull rod upper seal device, which increases the risk of leakage after long-term or excessive extrusion of the sealing ring inside.

[0009] 2. Technical scheme

[0010] In order to solve the above problems, the technical scheme adopted by the present application is as follows:

[0011] The upper seal device for the pull rod of a coal mill of the present application is used to be sleeved on the pull rod, which includes a first sealing sleeve, a second sealing sleeve and a sealing box distributed in an up-down manner; wherein,

[0012] A first sealing ring is arranged in the inner cavity of the first sealing sleeve, and a second sealing ring is arranged in the inner cavity of the second sealing sleeve;

[0013] One end of the second sealing sleeve is sealingly connected with the first sealing sleeve, and the first relative movement in the radial direction between the two can be carried out. The other end of the second sealing sleeve is sealingly connected with the sealing box, and the second relative movement in the radial direction between the two can be carried out, and the first relative movement occurs after the second relative movement is in place.

[0014] In some embodiments, first and second annular grooves for accommodating the first and second sealing rings are formed on the inner walls of the first and second sealing sleeves, respectively; wherein,

[0015] The top of the first sealing sheath has a first ring platform, the inner wall of the first ring platform comprises an upper and lower connected inclined surface and vertical surface, and the inclined surface, vertical surface and upper surface of the first sealing sheath form the first ring groove; and the outer peripheral wall of the first ring platform has an inclined surface at least at the top position.

[0016] In some embodiments, the inner peripheral wall of the second sealing ring is provided with a third ring groove, and the third ring groove is provided with a third sealing ring; wherein,

[0017] The hardness of the third sealing ring is greater than that of the second sealing ring, so that the third sealing ring can transmit the extrusion force to the second sealing ring when the third sealing ring is extruded radially by the pull rod, and the third sealing ring itself does not produce extrusion deformation.

[0018] In some embodiments, the second sealing ring comprises a first part and a second part connected to each other, and the inner and outer diameters of the first part are greater than those of the second part; wherein,

[0019] The inner wall of the first part and the upper surface of the second part form the third ring groove, and the outer peripheral wall of the first part has an inclined surface.

[0020] In some embodiments, the second sealing sheath, the first sealing sheath and the sealing box are connected by the structure of sliding groove and sliding block to realize corresponding radial movement.

[0021] In some embodiments, the second sealing sheath is provided with a second ring platform and a third ring platform, and the top of the sealing box is provided with a first connecting ring, and a first sliding groove for sliding cooperation with the second ring platform is formed between the first connecting ring and the upper surface of the sealing box.

[0022] The bottom of the first sealing sheath is provided with a second connecting ring, and a second sliding groove for sliding cooperation with the third ring platform is formed between the second connecting ring and the lower surface of the first sealing sheath.

[0023] In some embodiments, the outer peripheral wall of the second sealing sheath near the bottom is provided with a third sliding groove for inserting the first connecting ring, and the lower region of the third sliding groove forms the second ring platform.

[0024] In some embodiments, the first connecting ring and the sealing box, the second connecting ring and the first sealing sheath, and the first ring platform and the first sealing sheath are connected by bolts or are integrally formed.

[0025] In some embodiments, the first sealing ring and the second sealing ring are rubber sealing rings, and the third sealing ring is a metal sealing ring or a polytetrafluoroethylene sealing ring.

[0026] In some embodiments, the first sealing sheath and the second sealing sheath are both split structures; wherein the second connecting ring is provided with a connecting lug with a hole in the bottom, the gap on the outer peripheral wall of the first ring table, and the area between the third ring table and the third sliding groove.

[0027] 3. Advantage

[0028] Compared with the prior art, the utility model has the advantages of:

[0029] (1) The sealing device for the pull rod of the coal mill, the two ends of the second sealing sheath can move radially relative to the first sealing sheath and the sealing box, when the pull rod swings in a small range, both sealing sheaths can adapt to the swing of the pull rod to prevent the sealing ring from being extruded and deformed to increase the risk of sealing failure; as the swing range of the pull rod 100 continues to increase, although the second sealing ring will be extruded and deformed to have a risk of leakage after the second sealing sheath moves to the sealing box, the first sealing sheath and the second sealing sheath can still move, so the first sealing ring is not extruded, thereby ensuring the sealing performance of the whole device.

[0030] (2) The sealing device for the pull rod of the coal mill, the third sealing ring is provided, and the hardness of the third sealing ring is greater than that of the second sealing ring, so that when the third sealing ring is extruded by the pull rod, the extrusion force can be transmitted to the second sealing ring, causing the second sealing ring to deform to provide the necessary radial movement space for the third sealing ring to adapt to the swing of the pull rod; at the same time, the third sealing ring itself will not be extruded and deformed, thereby always maintaining the sealing performance of the pull rod.

[0031] (3) The sealing device for the pull rod of the coal mill, the first ring groove and the inclined surface at the top thereof are provided to limit the axial displacement of the first sealing ring; the inclined surface on the outer peripheral wall of the first ring table can guide the falling material falling on the first ring table to prevent the falling material from accumulating on the top of the first ring table, thereby increasing the risk of the falling material entering the sealing surface of the first sealing ring. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a structure schematic view of the sealing device for the pull rod of the coal mill of the utility model;

[0033] Figure 2 It is an internal structure schematic view of the sealing device for the pull rod of the coal mill of the utility model;

[0034] Figure 3 It is a structure schematic view of the pull rod box in the utility model;

[0035] Figure 4This is a schematic diagram of the structure of the first sealing sleeve in this utility model;

[0036] Figure 5 This is a schematic diagram of the structure of the second sealing sleeve in this utility model;

[0037] Figure 6 This is a schematic diagram of the structure of the second sealing ring in this utility model;

[0038] Figure 7 This is a schematic diagram of the assembly between the sealing device on the tie rod of a coal mill and the tie rod according to the present invention.

[0039] In the diagram: 100, pull rod; 200, sealing box; 210, first connecting ring; 220, first sliding groove;

[0040] 300, First sealing sleeve; 310, First annular platform; 311, First annular groove; 320, Second connecting ring; 330, Second sliding groove;

[0041] 400. Second sealing sleeve; 410. Second annular groove; 420. Second annular platform; 430. Third annular platform; 440. Third sliding groove;

[0042] 500, First sealing ring; 600, Second sealing ring; 610, Third annular groove; 620, First part; 630, Second part;

[0043] 700, Third sealing ring. Detailed Implementation

[0044] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings.

[0045] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] The present invention will be further described below with reference to specific embodiments.

[0047] like Figure 1 , Figure 2 as well as Figure 7As shown in the figure, a sealing device on the pull rod of a coal mill in this embodiment is integrally sleeved on the pull rod 100, used to seal the axial direction of the pull rod 100, and can adapt to the axial movement and radial swing of the pull rod 100.

[0048] The upper sealing device includes a first sealing sleeve 300, a second sealing sleeve 400, and a sealing box 200 distributed vertically. The first sealing sleeve 300 has a first sealing ring 500 inside its inner cavity, and the second sealing sleeve 400 has a second sealing ring 600 inside its inner cavity. The tight contact between the first sealing ring 500, the second sealing ring 600, and the pull rod 100 achieves an axial dynamic seal on the pull rod 100.

[0049] One end of the second sealing sleeve 400 is sealed to the first sealing sleeve 300, and the two can perform a first radial relative movement. The other end of the second sealing sleeve 400 is sealed to the sealing box 200, and the two can perform a second radial relative movement, with the first relative movement occurring after the second relative movement has reached its position.

[0050] In this embodiment, a sealing device on a coal mill pull rod allows the first sealing ring 500 and the second sealing ring 600 to swing synchronously with the pull rod 100 during a small-range swing. Since there is a certain radial movement space between the two ends of the second sealing sleeve 400 and the first sealing sleeve 300 and the sealing box 200 respectively, the first sealing ring 500 and the second sealing ring 600 are not compressed. Instead, they swing synchronously with the pull rod 100. Simultaneously, the relative movement mainly occurs between the second sealing sleeve 400 and the sealing box 200, while the second sealing sleeve 400 and the first sealing sleeve 300 move synchronously without relative movement. Therefore, the first relative movement can be considered not to have occurred at this point. As the swing amplitude of the pull rod 100 continues to increase, when the second relative movement between the second sealing sleeve 400 and the sealing box 200 reaches its destination, the second sealing ring 600 located within the inner cavity of the second sealing sleeve 400 will be subjected to a certain degree of compression and deformation, increasing the risk of leakage. However, since there is still a certain movement space between the second sealing sleeve 400 and the first sealing sleeve 300, the first relative movement has only just begun. Therefore, the first sealing ring 500 is not compressed before the first relative movement is in place, thus ensuring the sealing performance of the entire device.

[0051] It should be noted that in this embodiment, the first sealing ring 500 and the second sealing ring 600 can be organic seals with good elastic compensation performance to ensure that even after deformation due to compression, the seals can still guarantee the axial sealing performance of the pull rod 100 by utilizing their elastic compensation performance. It is also worth mentioning that although the first sealing ring 500 and the second sealing ring 600 can maintain a sealing effect by utilizing their own elastic compensation when subjected to radial compression from the pull rod 100, their elastic compensation performance will naturally gradually decrease after long-term or excessive compression, thereby increasing the risk of leakage. In this embodiment, radial sliding is performed in stages, so that the first sealing ring 500 is not compressed or excessively compressed during the swinging of the pull rod 100. Thus, even if the second sealing ring 600 fails to seal due to excessive or long-term compression, the first sealing ring 500 can still provide good sealing performance for the pull rod 100.

[0052] Furthermore, to facilitate the assembly of the first sealing sleeve 300 and the second sealing sleeve 400, both adopt a split structure as used in existing technology. Each split body is provided with a perforated connecting lug, and locking bolts are used to lock the connecting lugs on two corresponding split bodies to complete the assembly operation between the corresponding split bodies, forming the complete first sealing sleeve 300 and second sealing sleeve 400. Alternatively, sealing air can be introduced into the sealing box 200 to further improve the sealing performance of the entire upper sealing device.

[0053] In this embodiment of the sealing device on a coal mill tie rod, the first radial relative movement between the second sealing sleeve 400 and the first sealing sleeve 300, and the second radial relative movement between the second sealing sleeve 400 and the sealing box 200, can both be achieved through the structure of a groove or a slider, and are not specifically limited herein. For example, a groove or slider is provided on the upper part of the second sealing sleeve 400, and a corresponding slider or groove is provided on the lower part of the first sealing sleeve 300 to achieve the first radial relative movement between the two. Alternatively, a groove or slider is provided on the lower part of the second sealing sleeve 400, and a corresponding slider or groove is provided on the upper part of the sealing box 200 to achieve the second radial relative movement between the two. It should be noted that, regardless of which of the above-mentioned combinations is used, it must be ensured that the first relative movement occurs after the second relative movement has reached its position.

[0054] refer to Figures 2-5As shown, in some optional embodiments, a second annular platform 420 and a third annular platform 430 are provided on the second sealing sleeve 400, and a first connecting ring 210 is provided on the top of the sealing box 200. The first connecting ring 210 has an L-shaped cross-section, forming a first sliding groove 220 between it and the upper surface of the sealing box 200 for the second annular platform 420 to engage. Through the sliding engagement between the first sliding groove 220 and the second annular platform 420, a second radial relative movement between the second sealing sleeve 400 and the sealing box 200 is achieved.

[0055] A second connecting ring 320 is provided at the bottom of the first sealing sleeve 300. The cross-section of the second connecting ring 320 is L-shaped, so that a third ring platform 430 is inserted into the second sliding groove 330 between the second connecting ring 320 and the lower surface of the first sealing sleeve 300. Through the sliding engagement between the third ring platform 430 and the second sliding groove 330, the first radial relative movement between the second sealing sleeve 400 and the first sealing sleeve 300 is realized.

[0056] Furthermore, a third sliding groove 440 is formed on the outer peripheral wall of the second sealing sleeve 400 near the bottom, into which the first connecting ring 210 is inserted. The lower region of the third sliding groove 440 forms the aforementioned second annular platform 420. The third sliding groove 440 allows for a double-guided structure when the second sealing sleeve 400 slides against the sealing box 200, which helps ensure smooth sliding between them. Of course, this double-guided structure can also be designed between the second sealing sleeve 400 and the first sealing sleeve 300.

[0057] In some embodiments, the first connecting ring 210 and the sealing box 200, as well as the second connecting ring 320 and the first sealing sleeve 300, can be connected by bolts.

[0058] In some embodiments, the first connecting ring 210 and the sealing box 200, as well as the second connecting ring 320 and the first sealing sleeve 300, can be integrally molded.

[0059] In some embodiments, the second sealing sleeve 400 has a notch on its outer peripheral wall between the third annular platform 430 and the third sliding groove 440, and a connecting lug is provided in the notch.

[0060] like Figure 2 , Figure 4As shown, in one optional embodiment of the assembly structure between the first sealing ring 500 and the first sealing sleeve 300, a first annular platform 310 is provided on the top of the first sealing sleeve 300. The inner wall of the first annular platform 310 includes an inclined surface and a vertical surface connected vertically. The inclined surface is inclined towards the center of the first annular platform 310 as a whole. The inclined surface, the vertical surface, and the upper surface of the first sealing sleeve 300 form a first annular groove 311 for accommodating the first sealing sleeve 300.

[0061] Of course, the outer peripheral wall of the first sealing ring 500 must be compatible with the shape of the first annular groove 311. In this embodiment, by setting the inclined surface, the axial displacement of the first sealing ring 500 can be effectively limited to prevent the first sealing ring 500 from moving up and down synchronously with the pull rod 100, thereby affecting the sealing effect.

[0062] Furthermore, an inclined surface is also provided at the location where the outer peripheral wall of the first ring platform 310 connects to the top. This inclined surface guides the material falling onto the first ring platform 310, allowing it to slide smoothly. This prevents the material from accumulating on the top of the first ring platform 310, thus increasing the risk of the material entering the sealing surface of the first sealing ring 500. Of course, the same effect can be achieved if the entire outer peripheral wall of the first ring platform 310 is inclined.

[0063] Similarly, the first ring platform 310 and the first sealing sleeve 300 can be connected by bolts or by an integral molding design, without specific limitations.

[0064] In some embodiments, a connecting lug is provided at the bottom of the second connecting ring 320, which is located within the space formed between the first connecting ring 210 and the second connecting ring 320. A notch is provided on the outer peripheral wall of the first ring platform 310, and a connecting lug is also provided within the notch. The provision of two connecting lugs makes the assembly of the entire first sealing sleeve 300 more secure. At the same time, both connecting lugs are designed to be concealed, which can effectively reduce the risk of interference between the connecting lugs and other components during the movement of the entire sealing device.

[0065] like Figure 2 , Figure 5 As shown, in one optional embodiment of the assembly structure between the second sealing ring 600 and the second sealing sleeve 400, a second annular groove 410 is formed on the inner wall of the second sealing sleeve 400, and the second annular groove 410 is designed to penetrate the top of the second sealing sleeve 400. The second sealing ring 600 is confined within the area enclosed by the second annular groove 410 and the lower surface of the first sealing sleeve 300.

[0066] refer to Figure 2 , Figure 6As shown, in some optional embodiments, a third annular groove 610 is further provided on the inner peripheral wall of the second sealing ring 600, and a third sealing ring 700 is disposed within the third annular groove 610. The hardness of the third sealing ring 700 is greater than that of the second sealing ring 600, allowing the third sealing ring 700 to transfer the compressive force to the second sealing ring 600 when radially compressed by the pull rod 100. This causes the second sealing ring 600 to deform, providing radial movement space for the third sealing ring 700 to accommodate the swinging of the pull rod 100, while the third sealing ring 700 itself does not undergo compressive deformation. Thus, even if the second sealing ring 600 fails to seal due to compression, the third sealing ring 700 can still continue to provide an effective seal for the pull rod 100, preventing leakage.

[0067] It is worth mentioning that in this embodiment, the first sealing ring 500, the second sealing ring 600, and the third sealing ring 700 are all prior art and can be directly purchased from the market. For example, the first sealing ring 500 and the second sealing ring 600 are rubber sealing rings; the third sealing ring 700 is a metal sealing ring or a polytetrafluoroethylene (PTFE) sealing ring.

[0068] In some embodiments, the second sealing ring 600 includes a first portion 620 and a second portion 630 that are interconnected. The inner wall of the first portion 620 and the upper surface of the second portion 630 form the aforementioned third annular groove 610, and the third sealing ring 700 is confined within the area enclosed by the third annular groove 610 and the lower surface of the first sealing sleeve 300.

[0069] Since the compressive force on the third sealing ring 700 is mainly transferred to the first part 620 of the second sealing ring 600, if the entire third sealing ring 700 adopts a traditional cylindrical structure, the wall thickness of the first part 620 will be greatly reduced due to the presence of the third annular groove 610, and its compressible deformation will also be reduced, thus making it difficult to provide sufficient movement space for the third sealing ring 700. At the same time, when the swing amplitude of the pull rod 100 is too large, it is easy to cause excessive compression of the first part 620, affecting its sealing performance.

[0070] Therefore, in this embodiment, the first portion 620 of the second sealing ring 600 adopts an outward convex structure, which can effectively increase the wall thickness of the first portion 620, thereby providing more movable space for the third sealing ring 700. At the same time, it can avoid excessive compression due to excessive thickness.

[0071] Specifically, the first part 620 is located above the second part 630, and the inner diameter of the first part 620 is larger than the inner diameter of the second part 630, but smaller than the outer diameter of the second part 630; the outer diameter of the first part 620 is larger than the outer diameter of the second part 630. In other words, the first part 620 and the second part 630 are staggered vertically, and there is a partial contact area between them. It is worth noting that the second sealing ring 600 is divided into the first part 620 and the second part 630 here merely for ease of description. In reality, the second sealing ring 600 is integrally formed.

[0072] In some embodiments, the outer peripheral wall of the first portion 620 also has an inclined surface. By setting this inclined surface, the first portion 620 can have different wall thicknesses, which, while satisfying the radial movement distance of the third sealing ring 700, allows the compression loss of the first portion 620 to occur in stages, which also helps to ensure its sealing performance.

[0073] Specifically, in this embodiment, the outer peripheral wall of the first part 620 includes a vertical surface and an inclined surface connected vertically. The inclined surface is used to connect the vertical surface and the outer wall of the second part 630; and the inclined surface is inclined as a whole towards the center away from the first part 620, so that the wall thickness of the part corresponding to the inclined surface gradually increases from bottom to top.

[0074] This embodiment of a coal mill tie rod sealing device establishes a first radial relative movement and a second radial relative movement between the second sealing sleeve 400 and the first sealing sleeve 300 and the sealing box 200, respectively. These two relative movements occur sequentially, effectively preventing the first sealing ring 500 within the first sealing sleeve 300 from failing due to excessive compression, thus ensuring the overall sealing effect of the device. Simultaneously, the third sealing ring 700 is less susceptible to deformation under compression, and the compression deformation of the second sealing ring 600 provides necessary radial displacement space for the third sealing ring 700. This allows the third sealing ring 700 to provide good axial sealing performance for the tie rod 100 while accommodating its axial swing.

[0075] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A sealing device for a coal mill tie rod, used to be sleeved on the tie rod (100), characterized in that: It includes a first sealing sleeve (300), a second sealing sleeve (400), and a sealing box (200) distributed vertically; wherein, The first sealing sleeve (300) has a first sealing ring (500) in its inner cavity, and the second sealing sleeve (400) has a second sealing ring (600) in its inner cavity; One end of the second sealing sleeve (400) is sealed to the first sealing sleeve (300), and the two can perform a first radial relative movement; the other end of the second sealing sleeve (400) is sealed to the sealing box (200), and the two can perform a second radial relative movement, and the first relative movement occurs after the second relative movement is in place.

2. The sealing device on the pull rod of a coal mill according to claim 1, characterized in that: The inner walls of the first sealing sleeve (300) and the second sealing sleeve (400) are respectively provided with a first annular groove (311) and a second annular groove (410) for accommodating the first sealing ring (500) and the second sealing ring (600); wherein, The top of the first sealing sleeve (300) has a first annular platform (310), the inner wall of the first annular platform (310) includes an inclined surface and a vertical surface connected vertically, the inclined surface, the vertical surface and the upper surface of the first sealing sleeve (300) form the first annular groove (311); and the outer peripheral wall of the first annular platform (310) has an inclined surface at least at the top position.

3. A sealing device for a coal mill tie rod according to claim 1 or 2, characterized in that: The inner peripheral wall of the second sealing ring (600) is provided with a third annular groove (610), and a third sealing ring (700) is provided in the third annular groove (610); wherein, The hardness of the third sealing ring (700) is greater than that of the second sealing ring (600), so that when the third sealing ring (700) is radially compressed by the pull rod (100), it can transmit the compressive force to the second sealing ring (600), while the third sealing ring (700) itself will not be deformed by compression.

4. The sealing device on the pull rod of a coal mill according to claim 3, characterized in that: The second sealing ring (600) includes a first part (620) and a second part (630) connected to each other, wherein the inner and outer diameters of the first part (620) are both larger than those of the second part (630); wherein, The inner wall of the first part (620) and the upper surface of the second part (630) form the third annular groove (610), and the outer peripheral wall of the first part (620) has an inclined surface.

5. A sealing device for a coal mill tie rod according to claim 1, characterized in that: The second sealing sleeve (400) and the first sealing sleeve (300) and the sealing box (200) all achieve corresponding radial movement through the structure of sliding grooves and sliders.

6. The sealing device on the pull rod of a coal mill according to claim 5, characterized in that: The second sealing sleeve (400) is provided with a second ring platform (420) and a third ring platform (430), and the top of the sealing box (200) is provided with a first connecting ring (210), and a first sliding groove (220) is formed between the first connecting ring (210) and the upper surface of the sealing box (200) to slide in cooperation with the second ring platform (420); The bottom of the first sealing sleeve (300) is provided with a second connecting ring (320), and a second sliding groove (330) is formed between the second connecting ring (320) and the lower surface of the first sealing sleeve (300) to slide in cooperation with the third ring platform (430).

7. A sealing device for a coal mill tie rod according to claim 6, characterized in that: The second sealing sleeve (400) has a third sliding groove (440) on its outer peripheral wall near the bottom for the insertion of the first connecting ring (210), and the lower region of the third sliding groove (440) forms the second annular platform (420).

8. A sealing device for a coal mill tie rod according to claim 6, characterized in that: The first connecting ring (210) and the sealing box (200), the second connecting ring (320) and the first sealing sleeve (300), and the first ring platform (310) and the first sealing sleeve (300) are connected by bolts or integrally formed.

9. A sealing device for a coal mill tie rod according to claim 3, characterized in that: The first sealing ring (500) and the second sealing ring (600) are rubber sealing rings; the third sealing ring (700) is a metal sealing ring or a polytetrafluoroethylene sealing ring.

10. A sealing device for a coal mill tie rod according to claim 7, characterized in that: The first sealing sleeve (300) and the second sealing sleeve (400) both adopt a split structure; wherein, the bottom of the second connecting ring (320), the notch on the outer peripheral wall of the first ring platform (310), and the area between the third ring platform (430) and the third sliding groove (440) are all provided with perforated connecting lugs.

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