Explosion-proof device for coal mill

Abstract

The application relates to a coal mill explosion-proof device used for being installed on an air duct connected with a coal mill, wherein the coal mill explosion-proof device comprises a shell, a door cover assembly and an explosion-proof mechanism, the shell is provided with a pressure relief cavity and an opening, the pressure relief cavity is communicated with the opening; the shell is arranged on the air duct; the door cover assembly is movably arranged in the opening; the explosion-proof mechanism is connected with the door cover assembly, so that the shell is switched between an open state and a closed state; in the open state, the door cover assembly is located in the pressure relief cavity to expose the opening, the pressure relief cavity is communicated with the air duct through the opening; in the closed state, the door cover assembly covers the opening, so that the pressure relief cavity is isolated from the air duct. Therefore, the explosion-proof mechanism can adjust the movement process according to the pressure on the door cover assembly; when the pressure in the air duct gradually increases, the explosion-proof mechanism drives the door cover assembly to gradually contract and slowly release the pressure; when the pressure in the air duct sharply increases, the explosion-proof mechanism drives the door cover assembly to quickly contract and rapidly release the pressure.

Description

Technical Field

[0001] This application relates to the field of explosion-proof facilities technology, and in particular to an explosion-proof device for a coal mill. Background Technology

[0002] The thermal power plant has two 1000MW coal-fired steam turbine generator units. The boiler is a DG2910.12 / 29.15-Ⅱ3 type supercritical parameter variable pressure once-through boiler. This boiler has a single reheat, single furnace, balanced ventilation, solid ash discharge, open-air layout, partial enclosure, and all-steel frame design. The boiler adopts a Π-type layout and a front and rear wall opposed combustion method. Each boiler is equipped with a total of 6 ZGM123N-11 cold primary air positive pressure direct-fired medium-speed roller mills. The designed coal type is bituminous coal. The original design did not include explosion-proof doors.

[0003] With the changing quality of coal fed into the furnace, lignite and Indonesian coal are increasingly being blended. Lignite and Indonesian coal have high volatile matter content and are highly flammable and explosive; improper control during operation can pose significant safety risks. To ensure the safe and reliable operation of the unit, explosion-proof doors need to be added to the coal mill system.

[0004] Traditional template-type, gravity-type, and pure magnetic pre-tightening explosion-proof doors have problems such as being unable to reset after a deflagration, poor airtightness, requiring equipment to be shut down for repair, low explosion venting efficiency, and the possibility of malfunctions, which affect the reliability of equipment operation. Utility Model Content

[0005] Therefore, it is necessary to provide an explosion-proof device for coal mills to address the above-mentioned problems.

[0006] This application provides an explosion-proof device for a coal mill, for installation on an air duct connected to the coal mill, characterized in that the explosion-proof device comprises:

[0007] The housing has a pressure relief chamber and an opening, the pressure relief chamber being connected to the opening; the housing is disposed on the air duct;

[0008] A door cover assembly is movably disposed at the opening to allow the housing to switch between an open state and a closed state. In the open state, the door cover assembly is located within the pressure relief chamber to expose the opening, and the pressure relief chamber communicates with the air duct through the opening. In the closed state, the door cover assembly covers the opening to isolate the pressure relief chamber from the air duct.

[0009] In one embodiment, the explosion-proof device for the coal mill further includes a first elastic element disposed in the pressure relief chamber. One end of the first elastic element is connected to the housing, and the other end of the first elastic element is connected to the door cover assembly. The first elastic element is capable of extending and retracting to switch the housing between the open state and the closed state.

[0010] In one embodiment, the explosion-proof device for the coal mill further includes a limiting component, which is located on the side of the housing opposite to the opening, and the end of the first elastic member opposite to the door cover assembly is connected to the limiting component.

[0011] In one embodiment, the limiting component includes a first fixing plate, a second elastic member, and a second fixing plate. The first fixing plate is disposed on the housing. One end of the second elastic member is connected to the first fixing plate, and the other end of the second elastic member is connected to the second fixing plate. The end of the first elastic member facing away from the door cover assembly is connected to the second fixing plate.

[0012] In one embodiment, the explosion-proof device for the coal mill further includes a support rod, one end of which is connected to the housing and the other end of which is connected to the door cover assembly, and the first elastic element is sleeved on the support rod;

[0013] The support rod has a retracted state and an extended state. In the retracted state, the supporting force of the support rod and the elastic component on the door assembly is less than the pressure on the door assembly. The support rod retracts under pressure and drives the door assembly into the pressure relief chamber. In the extended state, the supporting force of the support rod and the elastic component on the door assembly is less than the pressure on the door assembly. The support rod extends and drives the door assembly to move toward the opening direction until the door assembly moves to the initial position.

[0014] In one embodiment, the door cover assembly includes a door panel and a seal, the door panel being movably disposed at the opening, and the seal being disposed at the door panel, wherein in the closed state, the door panel is sealed to the housing via the seal.

[0015] In one embodiment, the air duct is adapted to have a plurality of housings, the plurality of housings having a first axis, the air duct having a second axis, and the angle between the first axis and the second axis being 40° to 90°.

[0016] In one embodiment, multiple housings are provided, all of which are used to be disposed on the air duct, and the interval between two adjacent housings is greater than 100mm.

[0017] In one embodiment, the explosion-proof device for the coal mill further includes a protective cover, which is mounted on the housing and is coaxially arranged with the door cover assembly.

[0018] In one embodiment, the explosion-proof device for the coal mill further includes a fireproof net, which is disposed at the connection between the protective cover and the housing.

[0019] In the aforementioned explosion-proof device for coal mills, the door cover assembly is movably disposed within the housing, allowing the housing to switch between an open and closed state. In the open state, the door cover assembly is located within the pressure relief chamber, exposing the opening, which is connected to the air duct through the opening. In the closed state, the door cover assembly covers the opening, isolating the pressure relief chamber from the air duct. When the door cover assembly is subjected to pressure within the air duct, it contracts under pressure, thereby relieving the pressure within the air duct. When the door cover assembly is no longer subjected to pressure within the air duct, it returns to its initial position. Furthermore, the door cover assembly can adjust its movement according to the magnitude of the pressure it receives. When the pressure within the air duct gradually increases, the door cover assembly gradually contracts and slowly relieves pressure. Conversely, when the pressure within the air duct surges, the door cover assembly rapidly contracts and quickly relieves pressure. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the internal structure of the explosion-proof device for a coal mill in one embodiment of this application.

[0021] Figure 2 This is an enlarged view of the structure at point A of the explosion-proof device for a coal mill in one embodiment of this application.

[0022] Figure 3 This is a schematic diagram of the first installation position of the explosion-proof device for the coal mill in an embodiment of this application.

[0023] Figure 4 This is a schematic diagram of a second installation position of the explosion-proof device for a coal mill in an embodiment of this application.

[0024] Explanation of reference numerals in the attached figures:

[0025] 10. Housing; 11. Connector assembly;

[0026] 20. Door cover assembly; 21. Door panel; 22. Seals;

[0027] 30. Explosion-proof mechanism; 31. Elastic component; 311. First elastic element; 32. Support rod; 33. Limiting component; 331. First fixing plate; 332. Second elastic element; 333. Second fixing plate;

[0028] 40. Protective cover; 41. Fireproof netting;

[0029] 50. Air duct. Detailed Implementation

[0030] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0031] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, the term "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] This application provides an explosion-proof device for a coal mill, installed on an air duct 50 connected to the coal mill inlet. The explosion-proof device includes a housing 10 and a door cover assembly 20. The housing 10 is disposed on the air duct 50 and has a pressure relief chamber and an opening, with the pressure relief chamber communicating with the opening. The door cover assembly 20 is movably disposed on the opening, allowing the housing 10 to switch between an open and closed state. In the open state, the door cover assembly 20 is located inside the pressure relief chamber to expose the opening, and the pressure relief chamber communicates with the air duct 50 through the opening. In the closed state, the door cover assembly 20 covers the opening to isolate the pressure relief chamber from the air duct 50.

[0033] Therefore, by movably arranging the cover assembly 20 within the housing 10, when the cover assembly 20 is subjected to pressure within the air duct 50, the cover assembly 20 contracts under pressure, thereby relieving pressure within the air duct 50. When the cover assembly 20 is no longer subjected to pressure within the air duct 50, the cover assembly 20 returns to its original position. The cover assembly 20 can adjust its movement according to the magnitude of the pressure it receives. When the pressure within the air duct 50 gradually increases, the cover assembly 20 gradually contracts and slowly relieves pressure. When the pressure within the air duct 50 surges, the cover assembly 20 rapidly contracts and quickly relieves pressure.

[0034] In this embodiment, the housing 10 is designed as a cylinder with a circular cross-section. Its diameter is optionally set to 900 mm, and its height to 530 mm. This design provides the housing 10 with strong stability and resistance to deformation. Furthermore, the explosion-proof device includes a protective cover 40, which is installed on the outer wall of the housing 10 away from the air duct 50. The protective cover 40, housing 10, and door assembly 20 are all coaxially arranged. This coaxial arrangement enhances the overall explosion-proof impact resistance of the device.

[0035] Specifically, the elastic component 31, the support rod 32, and the limiting component together constitute the explosion-proof mechanism 30. The elastic component 31 is sleeved on the support rod 32. One end of the support rod 32 is connected to the door cover assembly 20, and the other end is connected to the housing 10. The support rod 32 has a retracted state and an extended state. In the retracted state, the supporting force of the support rod 32 and the elastic component 31 on the door cover assembly 20 is less than the pressure on the door cover assembly 20. The support rod 32 retracts under pressure and drives the door cover assembly 20 into the pressure relief chamber. In the extended state, the supporting force of the support rod 32 and the elastic component 31 on the door cover assembly 20 is less than the pressure on the door cover assembly 20. The support rod 32 extends and drives the door cover assembly 20 to move towards the opening direction until the door cover assembly 20 moves to its initial position.

[0036] For example, the support rod 32 can be a lead screw with higher impact resistance as the pull rod of the door cover assembly 20. This can maximize the impact resistance of the equipment and enhance the overall explosion resistance of the equipment during rapid explosion venting. At the same time, the lead screw enhances the stability of the equipment and also plays a guiding role when the door cover assembly 20 moves. It should be noted that the lead screw used here is an anti-rotation lead screw. This anti-rotation lead screw structure is existing technology, so its structure and working principle will not be described in detail in this embodiment. In addition, since the elastic component 31 is sleeved on the support rod 32, in this embodiment, the elastic component 31 includes a first elastic element 311, that is, the first elastic element 311 is sleeved on the support rod 32. The first elastic element 311 sleeved on the support rod 32 is compressed by pressure between the door cover assembly 20 and the housing 10. The compressed first elastic element 311 produces elastic deformation, but the housing 10 does not displace. The door cover assembly 20 is subjected to the force generated by the reset of the first elastic element 311, which can push the door cover assembly 20 to move toward the air duct 50.

[0037] Therefore, the force exerted by the first elastic element 311 on the door cover assembly 20 enables the door cover assembly 20 to actively reset. At the same time, when the door cover assembly 20 is subjected to the force exerted by the high pressure in the air duct 50, the force exerted by the first elastic element 311 on the door cover assembly 20 can offset part of the force exerted by the high pressure in the air duct 50, thereby alleviating the impact force generated when the door cover assembly 20 contracts. Finally, the pressure in the pressure relief chamber is released through the protective cover 40.

[0038] like Figure 2 As shown, the explosion-proof mechanism 30 also includes a limiting component 33, which is disposed on the housing 10 and extends toward the door cover assembly 20. Therefore, during the process of the door cover assembly 20 being compressed and contracting into the housing 10, the limiting component 33 can limit the contraction of the door cover assembly 20, preventing further contraction and compression of the first elastic element 311, thus avoiding permanent damage to the first elastic element 311 and its inability to effectively reset. Furthermore, when the limiting component 33 comes into contact with the door cover assembly 20, it indicates that the pressure on the door cover assembly 20 is enormous. At this point, the force exerted by the first elastic element 311 on the door cover assembly 20 to counteract the high pressure within the air duct 50 is insufficient. Therefore, the limiting component 33 provides stable support to the door cover assembly 20, ensuring that the entire explosion-proof device will not be subjected to excessive pressure and burst open.

[0039] Specifically, the limiting component 33 includes a first fixing plate 331, a second elastic member 332, and a second fixing plate 333. The limiting component 33 has a limiting housing 10. The first fixing plate 331 is disposed on the housing 10. One end of the second elastic member 332 is connected to the first fixing plate 331, and the other end of the second elastic member 332 is connected to the second fixing plate 333. That is, the second elastic member 332 is disposed between the second fixing plate 333 and the first fixing plate 331. The second elastic member 332 is mounted on the first fixing plate 331 by a suction cup. The side of the second fixing plate 333 opposite to the second elastic member 332 is connected to the limiting housing 10. The limiting housing 10, the first fixing plate 331, the second elastic member 332, the second fixing plate 333, and the first elastic member 311 are simultaneously fixed by a fixing member. Specifically, the fastener fixes one end of the first elastic member 311 to the limiting housing 10, and then the fastener passes through the limiting housing 10, the second fixing plate 333 and the second elastic member 332 in sequence until the fastener is embedded in the first fixing plate 331, thereby realizing the fixed installation between the first elastic member 311 and each component in the limiting assembly 33.

[0040] In this embodiment, the first elastic element 311 serves as the main reset element for the door cover assembly 20. However, when the preload of the first elastic element 311 is insufficient, the second elastic element 332 can supplement the insufficient preload of the first elastic element 311, thus forming a dual-force protection system with the first elastic element 311 and the second elastic element 332. Furthermore, the arrangement of the first elastic element 311 and the second elastic element 332 effectively mitigates the impact force generated by the retraction of the door cover assembly 20, preventing deformation of the door cover. Additionally, the second elastic element 332 prevents minor displacements caused by thermal expansion and contraction due to temperature changes during use. Minor displacements can easily lead to poor sealing; therefore, when poor sealing occurs, the second elastic element 332 can supplement the preload to reduce the likelihood of poor sealing.

[0041] In addition, the preload of the second elastic element 332 is adjustable. During adjustment, the second elastic element 332 is compressed to press the actuating suction cup. The actuating suction cup is compressed, which is equivalent to the actuating suction cup moving further away from the end of the door cover assembly 20. Then, the limiting housing 10, the first fixing plate 331, the second elastic element 332, the second fixing plate 333 and the first elastic element 311 are fixed at the same time by the fixing member. Thus, the detonation pressure can be finely adjusted by finely adjusting the second elastic element 332, so that the pressure of the second elastic element 332 is adjustable.

[0042] In one embodiment, the door cover assembly 20 includes a door panel 21 and a seal 22. A connecting plate is provided on the door panel 21 and is fixedly installed at the center of the door panel 21. One end of the support rod 32 is installed at the center of the connecting plate to ensure that the door panel 21, the housing 10, and the protective cover 40 are coaxially arranged. Additionally, a seal 22 is provided between the door panel 21 and the housing 10. The seal 22 can be a graphite stainless steel sealing ring. This graphite stainless steel sealing ring can reduce the performance degradation of the sealing ring caused by temperature, thus preventing leakage on-site. Furthermore, the graphite stainless steel sealing ring combines the high strength of stainless steel with the high temperature resistance and toughness of graphite. Therefore, during use, it can greatly enhance the sealing performance of the overall explosion-proof device and reduce the performance degradation of the sealing ring caused by temperature, thereby avoiding on-site leakage problems.

[0043] In one embodiment, the explosion-proof device for the coal mill also includes a fireproof net 41. The fireproof net 41 is made of a highly thermally conductive material and is installed at the connection between the protective cover 40 and the housing 10. This fireproof net can block or slow down the flames escaping from the air duct 50, preventing flames from causing a fire during an explosion and protecting operators from burns by hot air. Furthermore, the fireproof net 41 has good thermal conductivity, thus minimizing the temperature of the elastic component 31 and the protective cover 40, thereby extending the service life of the equipment and reducing the stress on the equipment caused by high-temperature environments.

[0044] like Figure 3 As shown, in one embodiment, the housing 10 is connected to the air duct 50 via a connecting pipe assembly 11, and the central axis of the housing 10 is a first axis A1, while the central axis of the air duct 50 is a second axis A2. After the housing 10 and the air duct 50 are connected, the included angle between the first axis A1 and the second axis A2 is 45°~90°. Furthermore, on the same air duct 50, the spacing between adjacent housings 10 is greater than 100mm to ensure that multiple housings 10 do not interfere with each other.

[0045] like Figure 3 As shown, in an optional embodiment, when the housing 10 is installed on the horizontal air duct 50, the housing 10 is installed vertically directly above the horizontal air duct 50. Specifically, the first axis A1 of the housing 10 is perpendicular to the second axis A2 of the horizontal air duct 50. This installation method ensures a tight connection between the housing 10 and the horizontal air duct 50, thereby improving the stability and reliability of the overall structure. Through this vertical installation, the housing 10 can better utilize the airflow in the air duct 50, ensuring smooth air circulation, while also facilitating maintenance and repair. Furthermore, this vertical installation design reduces space occupation, making the overall layout more compact and efficient.

[0046] like Figure 3 As shown, in an optional embodiment, when the housing 10 is installed on the horizontal air duct 50, the housing 10 can be installed at an angle to the side of the horizontal air duct 50. Specifically, the first axis A1 of the housing 10 forms a 45° angle with the second axis A2 of the horizontal air duct 50. Furthermore, the tilting direction of the housing 10 is upward. This tilting installation method allows the housing 10 to better adapt to the structure and airflow direction of the air duct 50 during actual use, thereby improving the overall ventilation efficiency and the operational stability of the equipment.

[0047] like Figure 4As shown, in an optional embodiment, when the housing 10 is installed on the vertical air duct 50, the housing 10 is not installed directly vertically, but rather at an angle. Specifically, a 45° angle is formed between the first axis A1 of the housing 10 and the second axis A2 of the vertical air duct 50. This angled installation makes the housing 10 appear tilted on the side of the vertical air duct 50. Furthermore, the tilting direction of the housing 10 is upward, which effectively utilizes space.

[0048] It should be noted that during installation, if it is a horizontal duct 50, the casing 10 should be installed vertically upwards as much as possible. If there is no suitable location directly above, then it should be installed at a 45° angle upwards. If it is a vertical duct, the casing 10 should be installed at a 45° angle upwards as much as possible, and horizontal or downward installation should be avoided as much as possible.

[0049] Therefore, the cover assembly 20 is installed inside the housing 10 via the explosion-proof mechanism 30. When the cover assembly 20 is subjected to pressure within the air duct 50, the explosion-proof mechanism 30 contracts under pressure, causing the cover assembly 20 to contract synchronously, thereby releasing the pressure within the air duct 50. When the cover assembly 20 is no longer subjected to pressure within the air duct 50, the explosion-proof mechanism 30 returns to its original position, simultaneously causing the cover assembly 20 to return to its initial position. Furthermore, the explosion-proof mechanism 30 can adjust its movement according to the magnitude of the pressure on the cover assembly 20: when the pressure within the air duct 50 gradually increases, the explosion-proof mechanism 30 causes the cover assembly 20 to gradually contract for slow pressure release; while when the pressure within the air duct 50 rises sharply, the explosion-proof mechanism 30 causes the cover assembly 20 to contract rapidly for rapid pressure release. Moreover, the explosion-proof device has an explosion-proof efficiency greater than 90%, which is 6 to 10 times that of traditional gravity-type explosion-proof equipment. Simultaneously, this explosion-proof device can automatically return to its original position after detonation without requiring shutdown, increasing the unit's equivalent availability factor. Furthermore, this explosion-proof device does not use superconducting materials (magnets) as the pressure source for the explosion-proof door, thus avoiding accidental explosions and eliminating potential risks. Simultaneously, because the explosion-proof mechanism 30 has a certain pre-tightening force, and the first elastic element 311 and the second elastic element 332 therein can automatically adapt to changes in the pressure received by the door cover assembly 20, it ensures that the door cover assembly 20 will not deform or experience other adverse conditions, thereby guaranteeing the stability of the pressure relief process.

[0050] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0051] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0052] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An explosion-proof device for a coal mill, used for installation on an air duct connected to the coal mill, characterized in that, The explosion-proof device for the coal mill includes: The housing has a pressure relief chamber and an opening, the pressure relief chamber being connected to the opening; the housing is disposed on the air duct; A door cover assembly is movably disposed at the opening to allow the housing to switch between an open state and a closed state. In the open state, the door cover assembly is located within the pressure relief chamber to expose the opening, and the pressure relief chamber communicates with the air duct through the opening. In the closed state, the door cover assembly covers the opening to isolate the pressure relief chamber from the air duct.

2. The explosion-proof device for a coal mill according to claim 1, characterized in that, The explosion-proof device for the coal mill also includes a first elastic element, which is disposed in the pressure relief chamber. One end of the first elastic element is connected to the housing, and the other end of the first elastic element is connected to the door cover assembly. The first elastic element can extend and retract to switch the housing between the open state and the closed state.

3. The explosion-proof device for a coal mill according to claim 2, characterized in that, The explosion-proof device for the coal mill also includes a limiting component, which is located on the side of the housing away from the opening, and the end of the first elastic element away from the door cover assembly is connected to the limiting component.

4. The explosion-proof device for a coal mill according to claim 3, characterized in that, The limiting component includes a first fixing plate, a second elastic member, and a second fixing plate. The first fixing plate is disposed on the housing. One end of the second elastic member is connected to the first fixing plate, and the other end of the second elastic member is connected to the second fixing plate. The end of the first elastic member facing away from the door cover assembly is connected to the second fixing plate.

5. The explosion-proof device for a coal mill according to claim 2, characterized in that, The explosion-proof device for the coal mill also includes a support rod, one end of which is connected to the housing and the other end of which is connected to the door cover assembly. The first elastic element is sleeved on the support rod. The support rod has a retracted state and an extended state. In the retracted state, the supporting force of the support rod and the first elastic element on the door cover assembly is less than the pressure on the door cover assembly. The support rod is compressed and retracts, driving the door cover assembly into the pressure relief chamber. In the extended state, the supporting force of the support rod and the first elastic element on the door cover assembly is less than the pressure on the door cover assembly. The support rod extends and drives the door cover assembly to move toward the opening direction until the door cover assembly moves to the initial position.

6. The explosion-proof device for a coal mill according to claim 1, characterized in that, The door cover assembly includes a door panel and a seal. The door panel is movably disposed in the opening, and the seal is disposed in the door panel. In the closed state, the door panel is sealed to the housing through the seal.

7. The explosion-proof device for a coal mill according to claim 1, characterized in that, The housing has a first axis, and the air duct has a second axis, with the angle between the first axis and the second axis being 40° to 90°.

8. The explosion-proof device for a coal mill according to claim 1, characterized in that, The housing is provided in multiple ways, and all of the housings are used to be installed on the air duct, and the interval between two adjacent housings is greater than 100mm.

9. The explosion-proof device for a coal mill according to claim 1, characterized in that, The explosion-proof device for the coal mill also includes a protective cover, which is installed on the housing and is coaxially arranged with the door cover assembly.

10. The explosion-proof device for a coal mill according to claim 9, characterized in that, The explosion-proof device for the coal mill also includes a fireproof net, which is installed at the connection between the protective cover and the housing.

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