Lower sealing structure of pull rod

Abstract

The utility model discloses a pull rod lower sealing structure, and belongs to the technical field of pull rod sealing. The sealing structure comprises a first sealing body, a second sealing body and a third sealing body which are sequentially sleeved from outside to inside, wherein a sealing part is arranged between each sealing body and the pull rod; the hardness of the second sealing body is larger than that of the first sealing body and that of the third sealing body, and the first sealing body and the third sealing body have elastic compensation performance. When the pull rod swings in the radial direction, the second sealing body can be prevented from being extruded and deformed through the strength of the second sealing body, and therefore the third sealing body in the inner cavity of the second sealing body can be protected, it is guaranteed that the third sealing body cannot be extruded, the third sealing body can tightly hold the pull rod all the time through the elasticity of the third sealing body, and good sealing performance is formed. Meanwhile, the second sealing body can transmit the extrusion force of the pull rod to the first sealing body, and the deformation of the first sealing body is utilized to provide a radial moving space for the second sealing body so as to adapt to the swing of the pull rod.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of pull rod sealing, more specifically, relates to a pull rod lower sealing structure. BACKGROUND

[0002] The coal mill is the key equipment for crushing 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 upper part of the coal mill by the hot air at the edge of the grinding disc, and under the action of the separator, the coarse coal powder will fall on the grinding disc for regrinding, and the qualified fine coal powder will be discharged with the airflow, which can be collected by the dust collecting 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 in the coal mill, which will dry the coal powder on one hand and send the coal powder out of the coal powder outlet at the upper part of the coal mill on the other hand, 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 in the actual working process of the coal mill, the sealing of the pull rod is relatively difficult, and 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, and 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 to compensate the air pressure of the hot air in the coal mill to prevent the coal powder from leaking under the action of hot air when the coal mill is working.

[0004] As in the patent of CN205371631U, a coal mill pull rod sealing device 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, the outer side of the upper seal elastomer has a conical surface, and the inner side has a circular arc groove. The application sets a upper seal shell circular gap between the upper seal shell and the upper seal connecting plate, and a lower seal shell circular gap between the lower seal shell and the lower seal elastomer, to adapt to the up and down movement and radial swing of the pull rod, so as to solve the easy wear between the pull rod and the upper and lower seals, and thus the phenomenon of powder leakage. However, in the process of swing of the pull rod, the lower seal elastomer is inevitably extruded and worn to a certain extent, although the lower seal elastomer has a certain elastic compensation performance, but after long time extrusion and wear, its sealing performance will also be affected, thus increasing the risk of leakage. Practical new type content

[0005] 1. Problem to be solved

[0006] In view of the problem that the existing pull rod lower seal device is easy to be extruded and worn, thus leading to the decline of its sealing performance, the utility model provides a pull rod lower seal structure, the third seal body is protected by the second seal body, so as to reduce the extrusion and wear of the third seal body, thus being beneficial to guarantee its sealing performance; at the same time, the extrusion deformation of the first seal body can provide a certain radial movement space for the second seal body, so as to adapt to the swing of the pull rod.

[0007] 2. Technical scheme

[0008] In order to solve the above problems, the technical scheme adopted by the utility model is as follows:

[0009] The utility model relates to a pull rod lower seal structure for being sleeved on a pull rod, the lower seal structure includes first seal body, second seal body and third seal body from outside to inside in turn, and each seal body has a sealing part with the pull rod; wherein,

[0010] The hardness of the second seal body is greater than that of the first seal body and the third seal body, and the first seal body and the third seal body have elastic compensation performance;

[0011] When the pull rod swings radially, the second seal body can protect the third seal body in its inner cavity; at the same time, the second seal body can transmit the extrusion force of the pull rod to the first seal body, and provide a radial movement space for the second seal body by the deformation of the first seal body.

[0012] In some embodiments, a first containing cavity for installing the second seal body is formed on the inner circumferential wall of the first seal body, and an inner lip is arranged at each of the upper and lower ends of the first containing cavity; wherein,

[0013] An annular groove is formed on the outer wall of the inner lip, and a pre-tightening member is arranged in the annular groove; a thorn part is formed on the inner wall of the inner lip, and the thorn part forms a sealing part in linear contact with the pull rod.

[0014] In some embodiments, the cross section of the inner lip is in a V-shaped structure as a whole, the opening side of the V-shaped structure forms the annular groove, and the other side gradually shrinks in the axial direction to form the thorn part, and the thorn part is located in the axial area occupied by the annular groove.

[0015] In some embodiments, a certain radial movement space is left between the second sealing body and the first containing cavity.

[0016] In some embodiments, the inner wall of the second sealing body is provided with a second containing cavity, and the third sealing body is limited in the second containing cavity and moves synchronously with the second sealing body.

[0017] The inner wall of the second sealing body is divided into upper and lower sealing parts by the second containing cavity, and the upper and lower sealing parts are in surface contact with the pull rod.

[0018] In some embodiments, the lower sealing structure further comprises a lower sealing base, and a third containing cavity for mounting the first sealing body is formed in the lower sealing base; the first sealing body has a certain radial movement space in the third containing cavity.

[0019] In some embodiments, the upper and lower ends of the outer peripheral wall of the first sealing body are each provided with a whole outwardly extending outer lip, the free ends of the two outer lips are arranged away from each other, and the outer lips are in contact sealing with the cavity wall of the third containing cavity.

[0020] In some embodiments, the hardness of the second sealing body is less than the hardness of the pull rod.

[0021] In some embodiments, the first sealing body and the third sealing body are rubber sealing rings, and the second sealing body is a metal sealing ring or a polytetrafluoroethylene sealing ring.

[0022] In some embodiments, the pre-tightening member is a spring or a clamp.

[0023] 3. Beneficial effects

[0024] Compared with the prior art, the beneficial effects of the utility model are:

[0025] (1) The utility model discloses a kind of lower sealing structures of pull rod, be provided with three sealing bodies by being successively sleeved from outside to inside, and the hardness of second sealing body is greater than first sealing body and third sealing body;When the pull rod occurs radial swing, second sealing body can protect third sealing body in its inner cavity, ensure that third sealing body is not extruded, so that third sealing body can hold tightly on pull rod, To ensure the sealing performance of pull rod;At the same time, second sealing body can pass the extrusion force of pull rod to first sealing body, and utilize the deformation of first sealing body to provide the radial movement space of second sealing body, to adapt the swing of pull rod.

[0026] (2) The utility model discloses a kind of lower sealing structures of pull rod, form a annular groove on the outer wall of inner lip, the annular groove is equipped with pre-tightening piece;At the same time, form a thorn part on the inner wall of inner lip, line contact can be formed between the thorn part and pull rod;Compared with traditional surface contact, under the action of the pre-tightening force provided by pre-tightening piece, line contact can effectively increase the contact pressure between pull rod, to improve sealing performance, prevent coal dust leakage. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is the structure diagram of a kind of lower sealing structure of pull rod of the utility model;

[0028] Figure 2 It is the structure diagram of first sealing body in the utility model;

[0029] Figure 3 It is the structure diagram of another assembly mode between first sealing body and second sealing body in the utility model;

[0030] Figure 4 It is the assembly diagram between a kind of lower sealing structure of pull rod of the utility model and pull rod.

[0031] In the drawing: 100, pull rod;

[0032] 200, sealing structure;210, first sealing body;211, first containing cavity;212, inner lip;2121, annular groove;2122, thorn part;213, outer lip;

[0033] 220, second sealing body;221, second containing cavity;230, third sealing body;240, pre-tightening piece;

[0034] 250, lower sealing base;251, third containing cavity. DETAILED DESCRIPTION

[0035] To further understand the contents of the utility model, the utility model is described in detail in conjunction with the drawings.

[0036] 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.

[0037] like Figure 4 As shown, the present invention provides a lower sealing structure 200 for a tie rod, which is integrally sleeved on the tie rod 100. It is mainly used for axial sealing of the tie rod 100 and can accommodate axial movement and radial oscillation of the tie rod 100. Simultaneously, the lower sealing structure 200 ensures that at least one elastic sealing element, while tightly gripping the tie rod 100, is not easily compressed by the tie rod 100, thereby reducing its compressive wear and ensuring a good sealing effect.

[0038] The present invention will be further described below with reference to specific embodiments.

[0039] like Figure 1 As shown, a lower sealing structure for a pull rod in this embodiment includes a first sealing body 210, a second sealing body 220, and a third sealing body 230, which are integrally arranged inside and outside the rod. The second sealing body 220 is disposed within the inner cavity of the first sealing body 210, and the third sealing body 230 is disposed within the inner cavity of the second sealing body 220. Each sealing body has at least one sealing portion between itself and the pull rod 100, thereby allowing multiple sealing portions to be formed at different axial positions of the pull rod 100 to ensure circumferential sealing performance of the pull rod 100.

[0040] Meanwhile, the hardness of the second sealing body 220 is greater than that of the first sealing body 210 and the third sealing body 230. The first sealing body 210 and the third sealing body 230 are elastic seals with good elastic compensation performance, such as rubber seals or seals made of other materials in the prior art, without specific limitations. However, it should be noted that the first sealing body 210 and the third sealing body 230 must be able to generate a certain clamping force on the pull rod 100 to ensure sealing performance; on the other hand, when subjected to radial compression by the pull rod 100, the first sealing body 210 and the third sealing body 230 can utilize their own elastic compensation performance to adapt to the radial swing of the pull rod 100.

[0041] The second sealing body 220 needs to be a sealing element with a certain degree of hardness. However, to reduce wear on the tie rod 100, the hardness of the second sealing body 220 needs to be less than that of the tie rod 100, which is typically made of steel. Therefore, the second sealing body 220 can be made of metal sealing rings or polytetrafluoroethylene (PTFE) sealing rings, etc., without specific limitations. Metal sealing rings, such as copper-based alloy sealing rings, are preferred due to their superior high-temperature resistance and wear resistance.

[0042] It is also important to note that the selection of the second sealing body 220 must ensure that it does not deform or only undergoes slight deformation when subjected to radial compression from the tie rod 100, without affecting its sealing performance against the tie rod 100. In this way, when the second sealing body 220 is subjected to radial compression from the tie rod 100, it can effectively protect the third sealing body 230 within its inner cavity, preventing the third sealing body 230 from being subjected to radial compressive force from the tie rod 100. This significantly reduces the compressive wear of the third sealing body 230, thereby extending its service life and ensuring a good sealing effect. Simultaneously, the second sealing body 220 can transmit the compressive force from the tie rod 100 to the first sealing body 210, and utilize the compressive deformation of the first sealing body 210 to provide a certain radial movement space for the second sealing body 220, accommodating the radial oscillation of the tie rod 100.

[0043] Specifically, refer to Figure 1 , Figure 2 As shown, a first receiving cavity 211 is formed on the inner peripheral wall of the first sealing body 210, and the second sealing body 220 is assembled into the first receiving cavity 211. Simultaneously, an inner lip 212 is provided at each of the upper and lower ends of the inner peripheral wall of the first sealing body 210 located within the first receiving cavity 211. It should be noted that "upper" and "lower" here refer to the axial direction of the pull rod 100, i.e. Figure 2 Up and down in the direction of the paper surface.

[0044] Similarly, a second receiving cavity 221 is provided on the inner wall of the second sealing body 220, and the third sealing body 230 is confined within the second receiving cavity 221. The inner wall of the second sealing body 220 is divided into upper and lower sealing portions by the second receiving cavity 221.

[0045] In some alternative embodiments, in order to increase the contact area between the second sealing body 220 and the pull rod 100 and ensure the sealing effect, the two sealing parts on the inner wall of the second sealing body 220 form surface contact with the pull rod 100.

[0046] In some alternative embodiments, an annular groove 2121 is formed on the outer wall of the inner lip 212, and a pre-tightening member 240, such as a spring, a clamp, or other existing component capable of providing pre-tightening force to the inner lip 212, is arranged in the annular groove 2121, which is not specifically limited herein. Meanwhile, a sharp portion 2122 is formed on the inner wall of the inner lip 212, which forms a sealing portion, and the sharp portion 2122 is in linear contact with the pull rod 100.

[0047] In conventional pull rod sealing structures, the contact area between the sealing member and the pull rod 100 is increased to improve the sealing performance, that is, the sealing portion is in surface contact with the pull rod 100. In the present embodiment, the sharp portion 2122 is in linear contact with the pull rod 100, and compared with the conventional surface contact, the contact area is greatly reduced, which seems to be not conducive to improving the sealing performance.

[0048] However, the inventor found through actual operation that when the inner lip 212 is in surface contact with the pull rod 100 and cooperates with the pre-tightening member 240, the pre-tightening force of the pre-tightening member 240 is dispersed at the contact surface and cannot provide good pre-tightening force to the entire contact surface. Especially after frequent swinging of the pull rod 100, a gap is formed between the sealing member and the pull rod 100, which leads to sealing failure. To solve this problem, the most effective way is to increase the locking force of the locking member 240 to increase the pre-tightening force of the sealing member and improve the contact pressure between the sealing member and the pull rod 100. However, it is found in actual use that excessive contact pressure in surface contact greatly increases the resistance of the pull rod 100 when moving in the axial direction. In severe cases, not only the normal movement of the pull rod 100 is affected, but also the friction loss between the sealing member and the pull rod 100 is increased, which is not conducive to the sealing effect of the pull rod 100.

[0049] In the present embodiment, the sharp portion 2122 is arranged between the inner lip 212 and the pull rod 100 to form linear contact. Since the contact area of linear contact is small, the pre-tightening force of the pre-tightening member 240 can be more concentrated at the linear contact, thereby effectively improving the gripping ability of the inner lip 212 to the pull rod 100 at the linear contact. Under the same swinging frequency, the gap at the linear contact is significantly improved, which is obviously beneficial to the sealing effect. Meanwhile, since the contact area between the sharp portion 2122 and the pull rod 100 is smaller, compared with the conventional surface contact, the resistance to the axial movement of the pull rod 100 under the same pressure will be smaller. It should be noted that the above-mentioned linear contact does not refer to the geometric sense of linear contact, but allows a certain width, which is greatly reduced compared with the conventional surface contact, and thus can be approximately regarded as linear contact.

[0050] Specific to the embodiment, the cross section of the inner lip 212 is in a V-shaped structure as a whole, the opening side of the V-shaped structure forms the annular groove 2121, and the other side gradually shrinks in the axial direction to form the sharp portion 2122. Meanwhile, the sharp portion 2122 is located in the axial area occupied by the annular groove 2121, so as to further increase the contact pressure between the sharp portion 2122 and the pull rod 100, and facilitate to ensure that the sharp portion 2122 can always hold the pull rod 100 during the swing of the pull rod 100.

[0051] From the above structure, it can be known that the lower sealing structure of the pull rod in the embodiment can form at least 5 sealing portions at different axial height positions of the pull rod 100. That is, the pulverized coal needs to pass through the sealing of the 5 sealing portions in sequence to complete the leakage, which obviously greatly reduces the possibility of the leakage of the pulverized coal. Meanwhile, the first sealing body 210 and the third sealing body 230 can be selected as rubber sealing members, and the second sealing body 220 can be selected as a metal sealing member, so that the elastic compensation performance of the rubber sealing member and the high-temperature resistance and wear resistance performance of the metal sealing member are organically combined together, which is also beneficial to improve the sealing performance of the entire lower sealing structure. More importantly, the third sealing body 230 is limited in the first accommodating cavity 211 of the second sealing body 220 and moves synchronously with the second sealing body 220, which can effectively reduce the extrusion and wear of the third sealing body 230 by the pull rod 100 and always hold the pull rod 100 by the elastic force of the third sealing body 230. In addition, the mutual cooperation between the sharp portion 2122 and the pre-tightening member 240 can effectively increase the contact pressure between the sharp portion 2122 and the pull rod 100, so as to be beneficial to improve the holding force of the inner lip 212 on the pull rod 100 and further ensure the sealing performance of the pull rod 100.

[0052] Reference Figure 3 In some optional embodiments, a certain radial movement space can be left between the second sealing body 220 and the first accommodating cavity 211. That is, a gap is left between the outer peripheral wall of the second sealing body 220 and the inner wall of the first accommodating cavity 211. That is, when the second sealing body 220 is radially extruded by the pull rod 100, the second sealing body 220 can first move in the radial movement space. Only when the second sealing body 220 is moved in place in the radial movement space, the swing of the pull rod 100 can be continued by compressing the first sealing body 210.

[0053] Reference Figure 1 , Figure 2As shown, the lower sealing structure of the pull rod in the embodiment further comprises a lower sealing base 250 installed at the bottom of the sealing box (not shown in the figure), and a third accommodating cavity 251 for installing the first sealing body 210 is formed in the lower sealing base 250. Similarly, the first sealing body 210 has a certain radial movement space in the third accommodating cavity 251. That is, the size of the third accommodating cavity 251 in the radial direction is greater than the maximum outer diameter of the first sealing body 210, so that when the inner lip 212 is subjected to the radial extrusion of the pull rod 100 and the extrusion force transmitted by the second sealing body 220, the first sealing body 210 can move in the radial movement space to adapt to the swing of the pull rod 100.

[0054] In some embodiments, the upper and lower ends of the outer peripheral wall of the first sealing body 210 are respectively provided with a whole outwardly extending outer lip 213, the free ends of the two outer lips 213 are arranged away from each other, and the outer lip 213 is in contact with the cavity wall of the third accommodating cavity 251 for sealing. Of course, the size of the third accommodating cavity 251 in the axial direction should be slightly smaller than the axial size of the two outer lips 213 of the first sealing body 210 in the free state, so as to ensure that when the two outer lips 213 are in contact with the upper and lower cavity walls of the third accommodating cavity 251, they can be extruded to form a good seal.

[0055] In some embodiments, the lower sealing base 250 comprises a base and a side plate, wherein one end of the side plate is connected with the bottom of the sealing box, and the other end is connected with the base. The side plate is in a whole Z shape, and the third accommodating cavity 251 is formed between the side plate and the base. The base and the side plate can be connected by bolts or integrally formed, which is not limited here.

[0056] The above describes the embodiments of the utility model and its implementation modes in a schematic manner, which is not restrictive, and the embodiments shown in the drawings are only one of the embodiments of the utility model, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired thereby, without departing from the creative purpose of the utility model, similar structural modes and embodiments can be designed without creativity, which should all belong to the protection scope of the utility model.

Claims

1. A drag link lower seal structure for fitting on a drag link (100), characterized in that: The lower sealing structure (200) comprises a first sealing body (210), a second sealing body (220) and a third sealing body (230) which are sequentially sleeved from outside to inside, and each sealing body has a sealing part with the pull rod (100); wherein, The hardness of the second sealing body (220) is greater than that of the first sealing body (210) and the third sealing body (230), and the first sealing body (210) and the third sealing body (230) have elastic compensation performance; When the pull rod (100) swings radially, the second sealing body (220) can protect the third sealing body (230) in the inner cavity thereof; at the same time, the second sealing body (220) can transmit the extrusion force of the pull rod (100) to the first sealing body (210), and utilize the deformation of the first sealing body (210) to provide the second sealing body (220) with a radial moving space.

2. The lower seal structure of claim 1, wherein: A first accommodating cavity (211) for installing the second sealing body (220) is formed on the inner circumferential wall of the first sealing body (210), and an inner lip (212) is arranged at each of the upper and lower ends of the first accommodating cavity (211). An annular groove (2121) is formed on the outer wall of the inner lip (212), and a pre-tightening member (240) is arranged in the annular groove (2121); a thorn part (2122) is formed on the inner wall of the inner lip (212), and the thorn part (2122) forms a sealing part in linear contact with the pull rod (100).

3. A drag-bush seal according to claim 2, wherein: The cross section of the inner lip (212) is in V-shaped structure as a whole, the opening side of the V-shaped structure forms the annular groove (2121), and the other side gradually shrinks in the axial direction to form the thorn part (2122), and the thorn part (2122) is located in the axial area occupied by the annular groove (2121).

4. A drag-bush seal according to claim 3, wherein: A certain radial moving space is left between the second sealing body (220) and the first accommodating cavity (211).

5. The lower seal structure of claim 2, wherein: A second accommodating cavity (221) is arranged on the inner wall of the second sealing body (220), and the third sealing body (230) is limited in the second accommodating cavity (221) and moves synchronously with the second sealing body (220); The inner wall of the second sealing body (220) is divided into upper and lower sealing parts by the second accommodating cavity (221), and the upper and lower sealing parts are in surface contact with the pull rod (100).

6. A drag-bush seal structure according to any one of claims 1 to 5, wherein: A lower sealing base (250) is further included, and a third accommodating cavity (251) for installing the first sealing body (210) is formed in the lower sealing base (250); the first sealing body (210) has a certain radial moving space in the third accommodating cavity (251).

7. A drag-bush seal according to claim 6, wherein: An outer lip (213) extending outward as a whole is arranged at each of the upper and lower ends of the outer circumferential wall of the first sealing body (210), the free ends of the two outer lips (213) are arranged away from each other, and the outer lip (213) is in contact sealing with the cavity wall of the third accommodating cavity (251).

8. A drag-bush seal according to any one of claims 1 to 5, wherein: The hardness of the second sealing body (220) is less than that of the pull rod (100).

9. The lower seal structure of claim 1, wherein: The first sealing body (210) and the third sealing body (230) are rubber sealing rings; the second sealing body (220) is a metal sealing ring or a polytetrafluoroethylene sealing ring.

10. The lower seal structure of claim 2, wherein: The pre-tightening member (240) is a spring or a clamp.

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