CN112797163A

CN112797163A - Coal mill

Info

Publication number: CN112797163A
Application number: CN202110164868.5A
Authority: CN
Inventors: 祁博渊
Original assignee: Maanshan City Rongyi Sealing Material Co ltd
Current assignee: Maanshan City Rongyi Sealing Material Co ltd
Priority date: 2021-02-06
Filing date: 2021-02-06
Publication date: 2021-05-14

Abstract

The invention discloses a coal mill, and belongs to the field of coal mills. The coal mill comprises a main shaft, a grinding disc and a shell, wherein a grinding disc sealing structure is arranged between the grinding disc and the shell, and a sealing base and a sealing ring are arranged between the main shaft and the shell; the sealing base is arranged at the bottom of the shell, the middle of the sealing base is provided with a central hole for the rotating shaft to pass through, and an annular sealing cavity which is opened towards the central hole is arranged in the sealing base; the sealing ring is of an annular structure, the middle of the sealing ring is provided with a mounting hole, the sealing ring is sleeved on the main shaft through the mounting hole, and the outer side wall of the annular main body of the sealing ring extends outwards in the circumferential direction to form a main lip and at least one auxiliary lip matched with the main lip; the main lip extends into the sealing cavity to be in contact sealing with the inner wall of the sealing cavity, and the auxiliary lip extends into the sealing cavity to be in contact sealing with the inner wall of the sealing cavity or is positioned outside the sealing cavity to be in contact sealing with the outer wall of the sealing cavity. The invention overturns the sealing structure for relative movement between the sealing element and the main shaft in the prior art, and effectively improves the sealing property between the main shaft and the shell.

Description

Coal mill

Technical Field

The invention belongs to the technical field of coal mills, relates to a sealing technology of a coal mill, and particularly relates to a sealing structure at a grinding disc and a main shaft in the coal mill.

Background

The coal mill is a key device for crushing coal blocks and other blocky materials into powdery materials, is widely applied to production industries of cement, silicate products, novel building materials, refractory materials, chemical fertilizers, black and non-ferrous metal ore dressing, glass ceramics and the like, and carries out dry-type or wet-type grinding on various ores and other grindable materials.

From the working principle, the coal mill can be divided into a ball type coal mill and a roller type coal mill, wherein the structure of the roller type coal mill is shown in fig. 1, and the working principle is as follows: the driving device 3 drives the grinding disc 1 to rotate by driving the main shaft 2 to rotate, the grinding roller 4 is arranged on a loading frame above the grinding disc 1, and the hydraulic loading device 5 provides grinding pressure for the grinding roller 4 during working by applying pressing force to the loading frame; when the coal mill works, materials fall in the center of the grinding disc 1 from the coal dropping pipe 6 above the grinding disc 1, the driving device 3 drives the grinding disc 1 to rotate, and meanwhile hot air enters the coal mill from the air inlet; along with the rotation of the grinding disc 1, the material moves towards the edge of the grinding disc 1 under the action of centrifugal force and is crushed by the grinding roller 4 when passing through the annular groove on the grinding disc 1; the crushed materials are brought up by the high-speed airflow of an air ring formed by hot air at the edge of the grinding disc 1 and move upwards along with the airflow to enter a separator at the upper part of the coal mill; when passing through the upper separator, under the action of a rotating rotor of the separator, coarse powder falls onto the grinding disc 1 to be ground again, and qualified fine powder is discharged out of the mill along with air flow and is collected by a dust collection device, so that a product is obtained.

When the coal mill works, in order to enable the coal powder to be smoothly sent out of the coal mill along with the airflow, the hot air can form larger air pressure in the coal mill, on one hand, the coal powder is dried, and on the other hand, the coal powder is sent out from a coal powder outlet at the upper part of the coal mill. However, the coal dust can be caused to be drilled with a seam under the action of internal wind pressure, the main shaft is in a rotating state during working, and the main shaft and the static coal mill shell cannot be in an integrated structure, namely, a seam must exist between the coal mill shell and the main shaft, so that the coal dust can be drilled out from the seam between the main shaft below the grinding disc and the coal mill shell under the action of the wind pressure, and a great amount of leakage of the coal dust and environmental pollution are caused. Therefore, the existing coal mill is generally provided with a sealing air chamber around a main shaft below a grinding disc, sealing elements are respectively arranged between a shell of the sealing air chamber and the bottom of the grinding disc and between the shell of the sealing air chamber and the main shaft, and when the coal mill works, sealing air is blown into the sealing air chamber to compensate the wind pressure of hot air in the coal mill, so that pulverized coal is prevented from leaking under the action of the hot air.

For example, the Chinese patent application number is: CN201920609491.8, published date: patent document 1/17/2020 discloses a coal mill base seal assembly and a coal mill, belonging to the field of coal mill seal structures. The assembly comprises an inner sealing shell and an outer sealing shell which are connected into an L-shaped structure, an inner sealing air chamber is formed between the inner sealing shell and the lower part of a grinding disc, an outer sealing air chamber is formed between the outer sealing shell and a main shaft, and the outer sealing air chamber and the inner sealing air chamber are of a mutually communicated structure. The upper end and the lower end of the outer sealed air cavity of the component are respectively provided with a double-seal structure, and sealed air is introduced into the outer sealed air cavity between the two double-seal structures. The assembly prevents pulverized coal from leaking from a gap between the outer sealing shell and the main shaft through the double sealing structure, and pulverized coal entering the lower part of the grinding disc along with hot air is blown to the inside of the coal mill through the introduced sealing air, so that the pulverized coal is further prevented from leaking.

However, this solution presents some problems in actual operation. Firstly, the main shaft and the double dynamic sealing structures rotate relatively, so that the binding surfaces of the dynamic sealing structures and the main shaft are abraded in a long-time working state, and the sealing performance of the main shaft is influenced. Secondly, let in sealed wind in the outside sealed wind cavity, thereby can play and blow the effect that prevents the buggy to coal pulverizer inside to reveal with the buggy, but it can be big with the clearance of blowing between dynamic seal structure and the main shaft equally, increases the risk that the buggy is revealed.

Meanwhile, the large blowing of the sealing air in the gap between the dynamic sealing structure at the lower end and the main shaft can lead to the leakage of the sealing air from the gap, so that the air pressure loss is caused, the output frequency of the sealing air is difficult to control, the balance of the air pressure between the outer sealing air chamber and the two sides in the coal mill can not be well guaranteed, and the sealing stability is influenced. And when stopping to blow in sealed wind or the amount of wind of blowing in sealed wind is less, then can make the pressure in the external seal wind cavity be less than coal pulverizer internal pressure, produce the suck-back phenomenon for during hot-blast drive buggy gets into the clearance between external seal wind cavity and main shaft and the dynamic seal structure, the wearing and tearing phenomenon between dynamic seal structure and the main shaft has aggravated on the one hand, on the other hand also can cause hot-blast loss, hot-blast efficiency of coal pulverizer upper portion discharge with the buggy in the reduction coal pulverizer.

Particularly, due to the characteristics of the main shaft in the rotating process, small-amplitude swing must exist in the radial direction during rotation of the main shaft, so that the contact precision of the sealing lip of the dynamic sealing structure and the main shaft is inconsistent, even different gaps occur, uneven wear of the dynamic sealing structure, loss of wind pressure and leakage of pulverized coal are caused, and loss of internal hot wind is also caused. Therefore, the dynamic sealing structure at the main shaft has relatively poor sealing stability, is relatively easy to leak, has relatively short sealing life and leads to relatively frequent maintenance.

Also, for example, the Chinese patent application number is: CN201822124796.8, published date: patent literature 11/12/2019 discloses a sealing device for a lower frame body of a coal mill, which comprises an inner sealing mechanism arranged in a slag discharge chamber and an outer sealing mechanism arranged at the lower end of a main shaft. The inner sealing mechanism consists of a first elastic seal, a metal soft seal, a pressure-resistant support and a fixing ring, and seals the space between the bottom of the deslagging chamber and the lower part of the millstone to prevent the coal powder from leaking. The outer sealing mechanism comprises a second elastic seal, a sealing press ring and a metal wear-resistant layer, a sealing cavity is arranged at the circumferential direction of the lower portion of the main shaft, and the second elastic seal is arranged in the cavity and clings to the main shaft to seal the main shaft.

This solution, although structurally different from the above solution, also presents some of the problems mentioned above. The main shaft and the second elastic seal perform relative rotation movement, and the dynamic sealing structure can cause the binding surface of the second elastic seal and the main shaft to be worn and influence the sealing performance of the main shaft under a long-time working state. Similarly, when the main shaft swings in the radial direction, uneven abrasion of the second seal, loss of wind pressure and leakage of pulverized coal are caused, and loss of internal hot air is also caused; meanwhile, pulverized coal also enters a space between the second elastic seal and the contact surface of the main shaft, so that the abrasion speed of the second elastic seal is further increased, and the sealing performance is reduced.

Disclosure of Invention

1. Problems to be solved

The invention provides a coal mill, and aims to solve the problems that the sealing performance between a main shaft of the coal mill and a shell of the coal mill is relatively poor, leakage is relatively easy to occur, the service life of the sealing is relatively short, and maintenance is relatively frequent. The coal mill changes the sealing form between the main shaft and the shell, overturns the sealing structure for relative movement between the sealing element and the main shaft in the prior art, effectively improves the sealing property between the main shaft and the shell, improves the sealing property, prolongs the service life of the sealing element and reduces the maintenance frequency.

2. Technical scheme

In order to solve the above problems, the present invention adopts the following technical solutions.

A coal mill comprises a main shaft, a grinding disc and a shell, wherein a grinding disc sealing structure is arranged between the grinding disc and the shell, and a main shaft sealing structure is arranged between the main shaft and the shell; the main shaft sealing structure comprises a sealing base and a sealing ring, wherein the main body of the sealing ring is of an annular structure, and a mounting hole is formed in the middle of the main body;

the sealing ring is sleeved on the main shaft through a mounting hole and synchronously rotates along with the main shaft, a sealing lip extends outwards from the outer side wall of the annular main body in the circumferential direction, and the sealing lip comprises a main lip and at least one auxiliary lip matched with the main lip;

the sealing base is arranged at the bottom of the shell, is of an annular structure as a whole and is provided with a central hole for the rotating shaft to pass through in the middle; the sealing base is provided with an annular sealing cavity, and the sealing cavity is of an opening structure towards the central hole;

the main lip of the sealing ring extends into the sealing cavity and is in contact sealing with the inner wall of the cavity of the sealing cavity; the auxiliary lip of the sealing ring extends into the sealing cavity and is in contact sealing with the inner wall of the cavity of the sealing cavity, or the auxiliary lip of the sealing ring is positioned outside the sealing cavity and is in contact sealing with the outer wall of the cavity of the sealing cavity.

As a further improvement of the technical solution, the secondary lip has one; the root of the auxiliary lip is close to the root of the main lip, and the main lip and the auxiliary lip are gradually far away when extending outwards; or the root of the auxiliary lip is far away from the root of the main lip, and the main lip and the auxiliary lip are gradually close to each other when extending outwards.

As a further improvement of the technical scheme, the two auxiliary lips are a first auxiliary lip and a second auxiliary lip which are respectively positioned at two sides of the main lip; the root of the first auxiliary lip is close to the root of the main lip, the main lip and the first auxiliary lip are gradually far away when extending outwards, and the first auxiliary lip is in contact sealing with the inner wall of the sealing cavity; the root of the second auxiliary lip is far away from the root of the main lip, the main lip and the second auxiliary lip gradually approach to each other when extending outwards, and the second auxiliary lip is in contact sealing with the outer wall of the sealing cavity.

As a further improvement of the technical scheme, the device also comprises a preload piece, wherein the preload piece is an annular elastic piece; when the root of the auxiliary lip is close to the root of the main lip, the main lip and the auxiliary lip are gradually far away when extending outwards, and the pre-tightening piece is sleeved on the outer wall of the sealing ring between the main lip and the auxiliary lip;

or when the root of vice lip is kept away from the root of main lip, main lip and vice lip outwards extend when being close to gradually, press close to on the sealing washer outer wall of vice lip for main lip one side, and/or the suit sets up on the vice lip the pretension piece.

As a further improvement of the technical scheme, when the root of the auxiliary lip is far away from the root of the main lip, the main lip and the auxiliary lip gradually approach each other when extending outwards, and a limit convex ring for limiting the axial movement of the preload piece is protruded on one side, opposite to the auxiliary lip, of the outer wall of the sealing ring.

As a further improvement of the technical scheme, a preload piece is sleeved on the outer wall of the sealing ring between the main lip and the first auxiliary lip; the second auxiliary lip is close to, and/or the second auxiliary lip is sleeved with the preload piece.

As a further improvement of the technical scheme, a limit convex ring for limiting the axial movement of the preload piece is protruded on one side of the outer wall of the sealing ring relative to the second auxiliary lip.

As a further improvement of the technical scheme, the preload piece is a hoop or a spring.

As a further improvement of the technical scheme, the sealing base comprises a base plate, a ring wall and a sealing ring disc; the base plate is a flange plate and is mounted on the shell through bolts, or the base plate is welded on the shell, or the base plate and the shell are of an integral structure; the sealing ring disc and the substrate are arranged at intervals and connected through two ends of the ring wall, so that a sealing cavity space is enclosed among the substrate, the ring wall and the sealing ring disc.

As a further improvement of the technical scheme, an oil filling port capable of filling lubricating media into the sealing cavity is formed in the sealing base.

3. Advantageous effects

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the coal mill, the sealing form between the main shaft and the shell is changed, the dynamic sealing structure of relative movement between the sealing element and the main shaft in the prior art is overturned, the sealing element and the main shaft do not move relatively in a synchronous movement mode, dust is difficult to enter between the sealing ring and the main shaft, and pulverized coal leakage cannot occur at the position; and moreover, the structural form of the sealing lips is designed, a main lip and auxiliary lip matching structure is adopted, and particularly, the main lip is matched with the two auxiliary lips respectively to form two groups of sealing structures. The main lip and the first auxiliary lip extend into the sealing cavity to form a relatively closed space, and the second auxiliary lip presses the outer surface of the sealing ring disc from the outer side to form a structure for tightly biting the sealing ring disc with the main lip; at the moment, the sealing ring and the main shaft integrally move synchronously, and compared with the traditional rotary dynamic seal between the main shaft and the shell, even if the main shaft swings radially, a gap is not formed between the sealing ring and the main shaft generally, and the phenomenon that the sealing ring is damaged due to friction between the sealing ring and the main shaft is avoided; meanwhile, the main lip, the first auxiliary lip and the second auxiliary lip form a triple sealing structure inside and outside the sealing cavity, and if hot air drives pulverized coal to enter the main shaft sealing structure, the pulverized coal is required to be leaked through the triple sealing in sequence, so that the sealing performance between the main shaft and the shell is effectively improved. Particularly, sealing air enters the sealing cavity through the first auxiliary lip, the main lip and the first auxiliary lip of the sealing ring are opened outwards, the inner wall of the sealing cavity is further pressed, the sealing air hardly leaks, the pressure of the sealing air hardly loses, and the sealing performance can be well guaranteed even if the main lip and the first auxiliary lip are abraded; simultaneously, the vice lip of second can also play when stopping letting in sealed wind, prevents that the outside air from suck-back to the effect in sealed chamber, can prevent effectively that external dust from flowing into between the seal lip of sealing washer and the sealed chamber and leading to aggravation seal lip wearing and tearing, the life of extension sealing washer.

(2) According to the coal mill, the preload piece with the annular elastic piece in structure is sleeved on the outer wall of the sealing ring, radial preload can be applied to the installed sealing ring, the combination tightness of the sealing ring and the main shaft is guaranteed, the sealing ring and the main shaft rotate synchronously all the time, and the possibility that dust enters the interface of the sealing ring and the main shaft is reduced; particularly, when the pre-tightening piece is sleeved between the main lip and the first auxiliary lip, the pre-tightening piece can extrude the main lip and the first auxiliary lip to two sides, so that a V-shaped structure formed by the main lip and the first auxiliary lip is outwards opened, the contact tightness between the main lip and the first auxiliary lip and the inner wall of the sealing cavity is further enhanced, the sealing performance is further improved, and the wear compensation effect of the sealing lips is achieved; when the pretensioning piece is pressed close to one side of the second auxiliary lip, which is opposite to the main lip, and is sleeved on the outer wall of the sealing ring, the second auxiliary lip can be squeezed, so that the contact tightness between the second auxiliary lip and the outer wall of the sealing ring disc is further enhanced, the sealing performance is further improved, and the abrasion compensation effect of the sealing lip is also realized.

(3) According to the coal mill, the sealing lip is arranged on the outer side wall of the sealing ring, compared with the traditional dynamic seal, the sealing lip is arranged on the surface attached to the main shaft, and can extend out by a longer height, so that even if the sealing lip is greatly abraded with the wall surface of the sealing cavity in the working process, the sealing lip can still be tightly attached to the wall surface of the sealing cavity by matching with sealing air, and the sealing performance of the main shaft is ensured;

(4) according to the coal mill, the oil injection port communicated with the sealing cavity is formed in the sealing base, lubricating media such as factice, graphite or butter can be injected into the sealing cavity through the oil injection port, an oil film can be formed on the inner wall of the sealing cavity contacted with the sealing lip, the friction resistance is reduced, the abrasion of the sealing lip is reduced, and the service life of the sealing cavity is prolonged; meanwhile, the lubricating medium filled in the seal cavity can further improve the sealing performance of the seal cavity.

(5) According to the coal mill, the sealing air chamber baffle is arranged around the outer side of the main shaft, the elastic seal is arranged on the sealing air chamber baffle, and the sealing air chamber is partitioned into an annular space formed between the enclosure guard plate and the sealing air chamber baffle and a long and narrow slit space formed between the sealing air chamber baffle and the main shaft sealing structure, so that the sealing effect is further improved, the sealing air pressure maintaining effect is further improved, and the possibility of back suction of hot air is further reduced; the metal soft seal can adapt to a high-temperature sealing environment caused by hot air and is not easy to damage.

(6) According to the coal mill, the scraper is arranged at the position close to the outer side of the lower part of the grinding disc and can synchronously rotate along with the grinding disc, so that coal gangue and stones which overflow from the side edge of the grinding disc under the action of centrifugal force and cannot be blown up by airflow due to large mass are scraped away and discharged through the stone coal discharge port arranged on the coal mill, and the coal gangue and the stones which are hard sundries are prevented from staying in the coal mill and causing large abrasion to parts of the coal mill.

Drawings

FIG. 1 is a schematic diagram of a prior art coal pulverizer;

FIG. 2 is a schematic view of a seal structure at the grinding disc and the main shaft of the coal pulverizer of the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

fig. 4 is a schematic structural diagram of the sealing ring of the present invention.

In the figure:

100. a seal ring; 110. a main lip; 120. a first minor lip; 130. a second minor lip; 140. pre-tightening piece; 150. a limit convex ring;

200. a main shaft;

300. a sealing base; 310. sealing the cavity; 320. a flange plate; 330. a sealing ring disc; 340. an annular wall;

400. a grinding disc;

500. a housing; 510. an air inlet; 520. a containment fender; 530. metal soft sealing; 540. compressing the flange; 550. a sealed plenum baffle; 560. elastic sealing;

600. a scraper.

Detailed Description

The invention is further described with reference to specific embodiments and the accompanying drawings.

Examples

The structure of the prior art coal mill is shown in fig. 1, and the working principle thereof is explained in detail in the background art. The coal mill is provided with a dynamic sealing structure between the shell and the bottom of the grinding disc and between the shell and the main shaft respectively, and a sealing air chamber is formed between the two dynamic sealing structures. Through detailed analysis of the background art, the sealing at the main shaft of the existing coal mill is realized by adopting a conventional dynamic seal, namely, the dynamic seal is in rotary contact with the main shaft through a sealing lip, but under the severe working conditions that the air pressure and the internal dust are large and the main shaft radially swings inside the coal mill, the traditional dynamic seal hardly ensures the stability of the seal, the leakage is easy to occur, the sealing service life is relatively short, and the maintenance is relatively frequent.

In order to solve the above problems, the present embodiment provides a coal mill, in which a sealing form between a main shaft and a housing is changed, a dynamic sealing structure for relative motion between a sealing element and the main shaft in the prior art is overturned, and a form in which the sealing element and the main shaft move synchronously without relative motion therebetween is adopted, so as to improve the sealing property between the main shaft and the housing. Meanwhile, the sealing structure between the grinding disc and the shell is optimized, and the sealing effect is integrally improved. The structure and operation of the specific seal of the coal pulverizer are described in detail below.

As shown in FIG. 2, a sealing arrangement of the mill grinding disc 400 and the main shaft 200 portion is shown. It can be seen that a grinding disc sealing structure is arranged between the bottom of the housing 500 and the grinding disc 400, a main shaft sealing structure is arranged between the housing 500 and the main shaft 200, a sealing air chamber is formed between the grinding disc sealing structure and the main shaft sealing structure through the housing 500, the grinding disc 400 and the main shaft 200, and sealing air can be introduced into the sealing air chamber through the air inlet 510.

As shown in fig. 2 and 3, the spindle sealing structure mainly includes a sealing base 300 and a sealing ring 100. The sealing base 300 is mounted at the outer bottom of the housing 500, and may be mounted by bolts or welding, or may be integrated with the housing 500. The sealing base 300 has an annular structure as a whole, a central hole for the spindle 200 to pass through is formed in the middle, and the sealing base 300 has an annular sealing cavity 310, and the sealing cavity 310 has an open structure toward the central hole. Specifically, in the present embodiment, the sealing base 300 includes a flange 320, a ring wall 340 and a sealing ring plate 330, the flange 320 is fixed to the housing 500 by bolts, the sealing ring plate 330 is spaced from the flange 320 and connected by two ends of the ring wall 340, and preferably, the sealing ring plate 340 is substantially parallel to and spaced from the flange 320. Thus, the space of the sealed cavity 310, i.e. the rectangular cavity with the right opening shown in the cross section of fig. 3, is enclosed by the flange 320, the annular wall 330 and the sealing ring plate 340. The structure of the seal base 300 is critical and it cooperates with the seal ring 100 to form a sealing surface, which is also a critical point needed to implement the inventive spindle seal structure of the present invention.

As shown in fig. 4, the sealing ring 100 for sealing the spindle 200 is different from a conventional dynamic sealing structure, and has an annular structure as a whole, and a mounting hole is formed in the middle for mounting the sealing ring 100 on the spindle 200, but unlike a structure in which a sealing lip extends from an inner wall of the mounting hole to a center of the conventional dynamic sealing structure, in this embodiment, the sealing ring 100 extends outward in a circumferential direction of an outer side wall of the annular main body to form a sealing lip, and the sealing lip cooperates with the sealing base 300 to form a sealing. Transition fit or interference fit can be adopted between the mounting hole of the sealing ring 100 and the main shaft 200, when the coal mill works, the sealing ring 100 rotates along with the main shaft 200 without relative rotation between the two, and the sealing lip of the sealing ring 100 extends into the sealing cavity of the sealing base 300 and is in contact sealing with the surface of the sealing cavity, so that the sealing ring 100 and the sealing base 300 are in rotary sealing, and the sealing form of the traditional dynamic sealing is completely overturned.

In order to achieve a better sealing effect, the sealing lip structure of the sealing ring 100 is optimally designed in the present embodiment. As shown in fig. 3 and 4, the seal ring 100 has at least one main lip 110, and the main lip 110 extends into the seal cavity 310 of the seal base 300 and seals with the surface of the seal ring disc 330. As the spindle 200 rotates, the primary lip 110 frictionally contacts the surface of the seal ring disk 330, forming a sealing surface. Of course, the seal ring 100 may also have a secondary lip that engages the primary lip 110 to improve sealing. In this embodiment, the seal ring 100 has two secondary lips, namely a first secondary lip 120 and a second secondary lip 130, on both sides of the primary lip 110, in addition to the primary lip 110. Wherein the root of the first minor lip 120 is close to the root of the major lip 110, and the major lip 110 and the first minor lip 120 gradually move away as they extend outwardly, forming a V-shaped configuration. When the sealing base 300 is installed, the main lip 110 and the first auxiliary lip 120 both extend into the sealing cavity 310 of the sealing base 300, the main lip 110 is in surface contact sealing with the sealing ring disc 330, and the first auxiliary lip 120 is in surface contact sealing with the flange disc 320, so that the opening of the sealing cavity 310 is completely closed. The root of the second minor lip 130 is distant from the root of the main lip 110, and the second minor lip 130 and the main lip 110 gradually approach each other as they extend outward, forming a figure-of-eight structure. When installed, the second sub lip 130 is located outside the seal base 300 and contacts the outer surface of the seal ring disc 330 of the seal base 300 to seal, that is, the seal ring disc 330 of the seal base 300 is inserted between the second sub lip 130 and the main lip 110 and is tightly caught.

It can be seen from the above design of the spindle sealing structure that the sealing ring 100 is fixedly connected with the spindle 200, and the two integrally and synchronously move, compared with the conventional rotary dynamic seal between the spindle and the housing, even if the spindle 200 radially swings, a gap generally does not exist between the sealing ring 100 and the spindle 200, and even more specifically, the phenomenon that the sealing ring 100 is damaged due to the friction between the two occurs is mentioned. In this case, the pulverized coal does not substantially enter between the seal ring 100 and the main shaft 200, and there is substantially no leakage therebetween. In order to better accommodate the radial oscillation of the spindle 200, the diameter of the sealing cavity 310 of the sealing base 300 may be slightly larger than the outer diameter of the sealing lip of the sealing ring 100, so as to ensure that a sufficient radial oscillation space is left.

The sealing arrangement of the sealing ring 100 with the sealing cavity 310 of the sealing base 300 is of critical importance. In this embodiment, the main lip 110, the first secondary lip 120 and the second secondary lip 130 together form a triple sealing structure inside and outside the sealing cavity 310, and it can be seen that the main lip 110 and the first secondary lip 120 are in one group and the main lip 110 and the second secondary lip 130 are in the other group. If hot air drives pulverized coal to enter the sealed air chamber, the pulverized coal is required to be sequentially subjected to triple sealing to cause leakage when reaching the sealing structure of the main shaft, and the sealing property between the main shaft 200 and the shell 500 can be effectively improved. More importantly, due to the V-shaped structural form of the main lip 110 and the first auxiliary lip 120, sealing air enters the sealing cavity 310 through the first auxiliary lip 120, the main lip 110 and the first auxiliary lip 120 of the sealing ring 100 are opened outwards, the inner wall of the sealing cavity 310 is further compressed, the sealing air is almost not leaked like an automobile vacuum tire structure, the sealing air pressure is almost not lost, pressure compensation is not needed to be carried out on the sealing air, the sealing air pressure is smaller, and the sealing air pressure can be kept consistent with or slightly larger than that of hot air. Further, even if the main lip 110 and the first sub lip 120 have abrasion, the sealing property can be well secured. Meanwhile, the second auxiliary lip 130 can also play a role in preventing external air from being sucked back to the sealing cavity 310 when the sealing wind stops being introduced, so that external dust can be effectively prevented from flowing into the space between the sealing lip of the sealing ring 100 and the sealing cavity 310 to aggravate the abrasion of the sealing lip, and the service life is prolonged. Of course, in order to further improve the sealing effect and reduce the friction, a saw-toothed structure may be provided at the contact position of the sealing lip and the sealing surface of the sealing ring 100.

The sealing air inlet 510 may also be selectively disposed on the sealing base 300, and the sealing air enters the sealing cavity 310 of the sealing base 300, so that the V-shaped structure formed by the main lip 110 and the first auxiliary lip 120 may be directly opened outwards, the compression effect on the V-shaped structure is better, and the sealing performance of the lower sealing structure is further improved.

In addition, the conventional dynamic seal generally arranges the sealing lip on the surface of the sealing ring, which is attached to the main shaft 200, and the size of the sealing lip is greatly limited, that is, the protruding height of the sealing lip is relatively short. And the sealing lip is arranged on the outer side wall of the sealing ring 100 in the embodiment, compared with the traditional dynamic sealing structure, the sealing lip can extend out by a longer height, so that even if the sealing lip is greatly abraded with the wall surface of the sealing cavity 310 in the working process, the sealing lip can still be tightly attached to the wall surface of the sealing cavity 310 by matching with sealing air, and the sealing performance of the main shaft 200 is ensured. Moreover, because the seal ring 100 and the main shaft 200 have no relative movement, the main shaft 200 may not be limited to a rotating shaft, and may be a square shaft or a rectangular shaft, and the shape of the mounting hole corresponding to the seal ring 100 is matched with that of the main shaft 200, so that the application range is wider.

Considering comprehensively the installation reliability and the sealing effect of the sealing ring 100, the present embodiment further performs an optimized design on the basis of the above-mentioned sealing ring 100, and adds the structural design of the preload member 140, and the structure of the preload member is an annular elastic member, and the preload member is sleeved on the outer wall of the sealing ring 100, and can apply a radial preload force to the installed sealing ring 100, so as to ensure the combination tightness between the sealing ring 100 and the main shaft 200, and the two rotate synchronously all the time, and further reduce the possibility that dust enters the interface between the two. One or more of the preload members 140 can be installed, and in the present embodiment, two preload members 140 are preferably installed, as shown in fig. 3 and fig. 4, wherein one preload member 140 is installed between the main lip 110 and the first minor lip 120, and in addition to the above radial preload effect, the more prominent effect is that it can press the main lip 110 and the first minor lip 120 to both sides, that is, the V-shaped structure formed by them is opened outwards, the contact tightness between the main lip 110 and the first minor lip 120 and the inner wall of the seal cavity is further enhanced, the sealing performance is further improved, and the seal lip wear compensation effect is provided. Another preload member 140 is disposed adjacent to the side of the second minor lip 130 opposite to the major lip 110 and is fitted over the outer wall of the seal ring 100, and a stopper ring 150 for restricting the axial movement of the preload member 140 is protruded from the outer wall of the seal ring 100 on the other side of the preload member 140. In addition to the radial pretensioning effect, the further pretensioning element 140 has a more prominent effect that it can squeeze the second secondary lip 130, so that the contact tightness between the second secondary lip 130 and the outer wall of the seal ring disk 330 is further enhanced, the sealing performance is further improved, and the seal lip wear compensation effect is also provided. In addition, the two preload pieces 140 are arranged at two axial ends of the sealing ring 100, so that the radial preload of the sealing ring 100 is more reliable. For the specific selection of the preload member 140, a clip or a spring, etc., which is an existing preload member, may be used, and in this embodiment, a clip is selected.

Furthermore, a preload member 140 can be further sleeved on the second secondary lip 130, and a radial preload force can be directly applied to the second secondary lip 130, so that the second secondary lip 130 is more tightly attached to the outer wall of the sealing cavity 310 of the sealing base 300. For the mounting of the second minor lip 130, it is conceivable to provide the second minor lip 130 with an annular groove, in which the second minor lip 130 is arranged.

In order to reduce the wear of the sealing ring 100 during operation, in the present embodiment, an oil filling port (not shown in the drawings) capable of filling the lubricating medium into the sealing cavity 310 is formed on the sealing base 300, and is particularly preferably arranged on the annular wall 340, and the oil filling port is in a closed state when not filled with the lubricating medium. Lubricating media such as ointment, graphite or butter can be injected into the sealing cavity 310 through the oil injection port, an oil film can be formed on the inner wall of the sealing cavity 310 contacted with the sealing lip, the friction resistance is reduced, the abrasion of the sealing lip is reduced, and the service life of the sealing ring 100 is prolonged; meanwhile, the lubricating medium filled in the seal cavity 310 can further improve the sealing performance of the seal cavity 310.

In the present embodiment, the above spindle seal structure is adopted for a coal mill, but the present invention is not limited to a coal mill, and may be selectively used only in consideration of the above-described severe conditions in the case of dynamic sealing of a rotating shaft, and only the mounting position of the seal base 300 is different and the seal ring 100 is fitted to a different rotating shaft. Therefore, the present embodiment provides an innovative structure form of the rotating shaft dynamic seal, which has a wide application field.

The grinding disc sealing structure is used as a sealing structure between the shell 500 and the bottom of the grinding disc 400, the existing structural form can be adopted, and the implementation is slightly modified on the basis of the existing structure. As shown in fig. 2, a sealing plenum baffle 550 is disposed around the spindle 200 in the housing 500, the shape of the top of the sealing plenum baffle 550 corresponds to the shape of the bottom of the grinding disc 400, and a rotatable space of the grinding disc 400 is reserved, so that a narrow gap is formed, and the entrance of sealing air into the spindle sealing structure is reduced. In the casing 500, an annular enclosure guard plate 520 is further arranged outside the seal plenum baffle 550, the lower end of the enclosure guard plate 520 is mounted at the bottom of the casing 500 through a flange, the upper end of the enclosure guard plate is provided with a metal soft seal 530, and the metal soft seal 530 is in contact seal with the bottom of the grinding disc 400, so that a seal plenum is formed between the enclosure guard plate 520 and the spindle seal structure. Because the enclosure guard plate 520 is close to the hot air inlet of the coal mill, the temperature is high and can reach 300-400 ℃, the conventional sealing element is very easy to damage and lose the function under the high-temperature environment, and the risk of coal dust leakage is increased, so that the metal soft seal 530 is adopted for sealing, the high-temperature sealing environment is adapted, and the damage is not easy. In addition, the metal soft seal 530 can be fixedly arranged on the apron guard plate 520 through the annular pressing flange 540, and the assembly, disassembly and replacement are also convenient.

In this embodiment, an elastic seal 560 is further installed on the seal plenum baffle 550, and is also in contact seal with the bottom of the grinding disc 200, so that the seal plenum is divided into two parts, namely an annular space formed between the containment guard plate 520 and the seal plenum baffle 550, and a narrow and long slit space formed between the seal plenum baffle 550 and the spindle seal structure, thereby further improving the sealing effect, further improving the seal plenum effect, and further reducing the possibility of back suction of hot air.

In addition, this embodiment still is equipped with scraper blade 600 in the position that the outside is close to in mill 400 lower part, and scraper blade 600 can rotate along with mill 400 is synchronous, will be unable blown up by the air current because of the quality is great, scrapes away from coal gangue and the stone that spills over from mill 400 side under the centrifugal force effect to stone coal discharge port through setting up on the coal pulverizer discharges, prevents that this kind of harder debris of coal gangue and stone from stopping in the coal pulverizer, causes great wearing and tearing to the part of coal pulverizer.

In summary, the coal mill of the embodiment changes the sealing form between the traditional main shaft and the shell, the sealing element and the main shaft move synchronously, the sealing performance between the main shaft and the shell is improved, the sealing performance is improved, and the service life of the sealing element is prolonged.

The present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching, without departing from the spirit of the invention, the person skilled in the art shall not inventively design the similar structural modes and embodiments to the technical solution, but shall fall within the scope of the invention.

Claims

1. A coal pulverizer comprising a main shaft (200), a grinding disc (400), and a housing (500), with a grinding disc sealing structure between the grinding disc (400) and the housing (500), and a main shaft sealing structure between the main shaft (200) and the housing (500); the main shaft sealing structure comprises a sealing base (300) and a sealing ring (100), wherein the main body of the sealing ring (100) is of an annular structure, and a mounting hole is formed in the middle of the sealing ring; the method is characterized in that:

the sealing ring (100) is sleeved on the main shaft (200) through a mounting hole and synchronously rotates along with the main shaft (200), a sealing lip extends outwards from the outer side wall of the annular main body in the circumferential direction, and the sealing lip comprises a main lip (110) and at least one auxiliary lip matched with the main lip (110);

the sealing base (300) is arranged at the bottom of the shell (500), is of an annular structure as a whole, and is provided with a central hole for the rotating shaft to pass through in the middle; the sealing base (300) is provided with an annular sealing cavity (310), and the sealing cavity (310) is of an open structure towards the central hole;

the main lip (110) of the sealing ring (100) extends into the sealing cavity (310) and is in contact sealing with the inner wall of the cavity of the sealing cavity (310); the auxiliary lip of the sealing ring (100) extends into the sealing cavity (310) and is in contact sealing with the inner wall of the cavity of the sealing cavity (310), or the auxiliary lip of the sealing ring (100) is positioned outside the sealing cavity (310) and is in contact sealing with the outer wall of the cavity of the sealing cavity (310).

2. The coal pulverizer of claim 1, wherein: said minor lip has one; the root of the auxiliary lip is close to the root of the main lip (110), and the main lip (110) and the auxiliary lip are gradually far away when extending outwards; or the root of the auxiliary lip is far away from the root of the main lip (110), and the main lip (110) and the auxiliary lip are gradually close when extending outwards.

3. The coal pulverizer of claim 1, wherein: the two auxiliary lips are a first auxiliary lip (120) and a second auxiliary lip (130) which are respectively positioned at two sides of the main lip (110); the root of the first auxiliary lip (120) is close to the root of the main lip (110), the main lip (110) and the first auxiliary lip (120) are gradually far away when extending outwards, and the first auxiliary lip (120) is in contact sealing with the inner wall of the sealing cavity (310); the root of the second auxiliary lip (130) is far away from the root of the main lip (110), the main lip (110) and the second auxiliary lip (130) gradually approach when extending outwards, and the second auxiliary lip (130) is in contact sealing with the outer wall of the cavity body of the sealing cavity (310).

4. The coal pulverizer of claim 2, wherein: the device also comprises a preload piece (140), wherein the preload piece (140) is an annular elastic piece; when the root of the auxiliary lip is close to the root of the main lip (110), and the main lip (110) and the auxiliary lip are gradually far away when extending outwards, the preload piece (140) is sleeved on the outer wall of the sealing ring (100) between the main lip (110) and the auxiliary lip;

or when the root of the auxiliary lip is far away from the root of the main lip (110), the main lip (110) and the auxiliary lip extend outwards to gradually approach, the auxiliary lip is arranged on the outer wall of the sealing ring (100) on one side of the auxiliary lip relative to the main lip (110), and/or the preload piece (140) is sleeved on the auxiliary lip.

5. The coal pulverizer of claim 4, wherein: when the root of the auxiliary lip is far away from the root of the main lip (110), and the main lip (110) and the auxiliary lip gradually approach when extending outwards, a limit convex ring (150) for limiting the axial movement of the preload piece (140) is protruded on one side of the outer wall of the sealing ring (100) opposite to the auxiliary lip.

6. The coal pulverizer of claim 3, wherein: a preload piece (140) is sleeved on the outer wall of the sealing ring (100) between the main lip (110) and the first auxiliary lip (120); the preload piece (140) is arranged on the outer wall of the sealing ring (100) close to one side of the second auxiliary lip (130) relative to the main lip (110) in a sleeved mode, and/or the second auxiliary lip (130) is sleeved with the preload piece.

7. The coal pulverizer of claim 6, wherein: and a limiting convex ring (150) for limiting the axial movement of the preload piece (140) protrudes from one side of the outer wall of the sealing ring (100) relative to the second auxiliary lip (130).

8. The coal pulverizer of any of claims 4-7, wherein: the preload piece (140) is a clamp or a spring.

9. The coal pulverizer of claim 1, wherein: the sealing base (300) comprises a base plate, a ring wall (340) and a sealing ring disc (330); the base plate is a flange plate (320) and is installed on the shell (500) through bolts, or the base plate is welded on the shell (500), or the base plate and the shell (500) are of an integral structure; the sealing ring disc (330) and the substrate are arranged at intervals and are connected through two ends of the ring wall (340), so that a sealing cavity (310) space is enclosed among the substrate, the ring wall (340) and the sealing ring disc (330).

10. The coal pulverizer of any of claims 1-7, 9, wherein: an oil filling port capable of filling lubricating media into the sealing cavity (310) is formed in the sealing base (300).