Coal mill nitrogen extinguishing system

Abstract

The utility model relates to nitrogen fire extinguishing technical field especially relates to coal mill nitrogen fire extinguishing system, including nitrogen loading unit, a plurality of branch pipelines, pilot control subassembly and airflow distribution subassembly, the nitrogen loading unit includes a plurality of nitrogen cylinders, and the output end of a plurality of nitrogen cylinders is connected with main pipeline in common, the output end of a plurality of branch pipelines is located at each combustible point position in coal mill house respectively, the output end of a plurality of branch pipelines is equipped with temperature sensor, the pilot control subassembly includes the pilot gas tank of loading nitrogen and the pilot pipeline connected with pilot gas tank output end, the utility model discloses through setting up pilot control subassembly, utilize high pressure nitrogen gas in pilot gas tank as pilot gas source, response speed is far faster than nitrogen loading unit's long distance delivery speed, after pilot valve opens, pilot airflow can reach the fire point first, starts the preliminary explosion suppression process, and gains time for the arrival of main airflow in nitrogen loading unit.

Description

Technical Field

[0001] This utility model relates to the field of nitrogen fire extinguishing technology, and in particular to a nitrogen fire extinguishing system for coal mills. Background Technology

[0002] In industries such as cement and power generation, raw coal needs to be ground into pulverized coal for combustion. Pulverized coal is a highly flammable and explosive substance, and the consequences of a fire or explosion are extremely serious. To provide rapid and effective fire protection for coal mills, a major hazard source, and to prevent the fire from spreading and causing an explosion, a large amount of nitrogen gas is typically released into the fire area to rapidly reduce the oxygen concentration in that space. However, when the fire extinguishing point is far from the gas cylinder room, the excessively long main pipeline can significantly increase the time from nitrogen release to discharge, failing to meet the rapid response requirements for explosion suppression.

[0003] Based on the above situation, we propose a coal mill nitrogen fire extinguishing system to solve the above problems. Utility Model Content

[0004] This invention provides a nitrogen fire extinguishing system for coal mills to solve the problems existing in the prior art.

[0005] The technical problem solved by this utility model is achieved by the following technical solution: A nitrogen fire extinguishing system for a coal mill includes a nitrogen storage unit, multiple branch pipelines, a pilot control component, and an airflow distribution component. The nitrogen storage unit includes multiple nitrogen cylinders, and the output ends of these cylinders are connected to a main pipeline. The output ends of the branch pipelines are located at various flammable points within the coal mill, and each branch pipeline output end is equipped with a temperature sensor. The pilot control component includes a pilot gas tank containing nitrogen and a pilot pipeline connected to the output end of the pilot gas tank. The pilot pipeline is connected to the multiple branch pipelines via connecting pipes, and a pilot valve is installed on the pilot pipeline. The pilot gas tank is configured such that when the pilot valve opens according to a fire signal, the high-pressure gas inside is released first through the pilot pipeline to trigger the opening of the nitrogen storage unit and reach the fire extinguishing point before the main airflow of the nitrogen storage unit. The airflow distribution component is connected to the output ends of the pilot pipeline and the main pipeline, and is used to simultaneously open the nitrogen storage unit when the pilot control component depressurizes.

[0006] Preferably, the airflow distribution assembly includes a distribution chamber and a piston plate located inside the distribution chamber. The piston plate divides the distribution chamber into an upper cavity and a lower cavity. A spring connects the piston plate and the lower cavity. A connecting pipe connects the upper cavity and the pilot guide circuit. The cross-section of the upper cavity is larger than that of the lower cavity, and the piston plate is slidably and sealingly connected to the interior of the lower cavity.

[0007] Preferably, a telescopic guide rod is connected between the piston plate and the lower cavity to guide the movement position of the piston plate.

[0008] Preferably, the upper cavity is provided with a piston chamber that communicates with the pilot guide circuit, and a piston rod extending to the outside of the piston chamber is slidably connected inside the piston chamber for abutting against the piston plate.

[0009] Preferably, the system also includes a controller, and the branch pipe is equipped with a control valve. When the controller receives a temperature sensor on the corresponding branch pipe that detects that the temperature exceeds the set range, it controls the corresponding control valve to open.

[0010] Preferably, a pressure gauge is provided in the upper chamber.

[0011] The beneficial effects of this utility model are as follows: by setting a pilot control component, the high-pressure nitrogen in the pilot gas tank is used as the pilot gas source. The response speed is much faster than the long-distance delivery speed of the nitrogen gas carrier unit. After the pilot valve is opened, the pilot gas flow can reach the extinguishing point first and start the initial explosion suppression process, which buys time for the arrival of the main gas flow in the nitrogen gas carrier unit, solves the problem of delivery lag caused by excessively long pipelines, and meets the rapid response requirements for explosion suppression in coal mill systems. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0013] Figure 1 Structural schematic diagram provided for this utility model Figure 1 ; Figure 2 Structural schematic diagram provided for this utility model Figure 2 ; Figure 3 A schematic diagram of the airflow distribution component provided by this utility model; Figure 4 This is a system block diagram provided in this utility model.

[0014] In the diagram, 1. Nitrogen cylinder; 11. Main pipeline; 2. Branch pipeline; 21. Temperature sensor; 3. Pilot control assembly; 31. Pilot gas tank; 32. Pilot pipeline; 33. Pilot valve; 4. Distribution chamber; 41. Piston plate; 42. Upper chamber; 43. Lower chamber; 44. Spring; 5. Connecting pipe; 6. Telescopic guide rod; 7. Piston chamber; 71. Piston column; 8. Controller; 81. Control valve; 9. Pressure gauge. Detailed Implementation

[0015] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the following description, in conjunction with specific illustrations, further elaborates on this utility model. Example 1

[0016] Reference Figures 1-4 As shown, the coal mill nitrogen fire extinguishing system includes a nitrogen storage unit, multiple branch pipes 2, a pilot control component 3, and an airflow distribution component. The nitrogen storage unit can be composed of multiple nitrogen cylinders 1, each capable of holding nitrogen at a working pressure of 15 MPa. The outlets of all nitrogen cylinders 1 are connected to a main pipe 11 via a manifold. Inside the coal mill, multiple branch pipes 2 are laid corresponding to flammable points such as the mill, dust collector, and coal powder silo. The nozzle at the end of each branch pipe 2 is aimed at the critical parts of the corresponding equipment. Each branch pipe 2 has... A normally closed control valve 81 is installed as the control valve. The pilot control assembly 3 is installed near the coal mill and includes a pilot gas tank 31 filled with high-pressure nitrogen. The outlet of the pilot gas tank 31 is connected to the airflow distribution assembly via a pilot line 32. A pilot valve 33 is installed on the pilot line 32. The airflow distribution assembly is a specially designed pilot-operated distribution valve, the valve body of which is the distribution chamber 4. A piston plate 41 is installed in the distribution chamber 4. The piston plate 41 is guided by a telescopic guide rod 6 to ensure that it can only move vertically up and down. The piston plate 41 divides the interior of the distribution chamber 4 into an upper chamber 42 and a lower chamber 43. A return spring 44 is connected between the piston plate 41 and the bottom of the lower chamber 43.

[0017] The inner diameter of the upper cavity 42 is designed to be larger than that of the lower cavity 43, so that the pressure-bearing cross-sectional area of ​​the upper cavity 42 is larger than that of the lower cavity 43. The inlet of the lower cavity 43 is connected to the main pipe 11. A connecting pipe 5 is provided on the upper cavity 42 to connect the pilot pipe 32 to the upper cavity 42 of the distribution chamber 4. A piston chamber 7 is also provided on the upper cavity 42. There is a piston column 71 in the piston chamber 7. One end of the piston column 71 can press against the piston plate 41 under the action of air pressure, but its main force still comes from the air pressure difference. A throttling pipe is provided on the wall of the distribution chamber 4. The throttling pipe connects the lower cavity 43 and the upper cavity 42. The throttling pipe is a slender metal tube with an internal aperture of less than 2 cm.

[0018] Specifically, when the system is in standby mode, the pressure of the nitrogen gas holding unit slowly permeates to the lower chamber 43 and the upper chamber 42 through the throttling tube. Eventually, the pressure of the entire system is balanced. Since the cross-sectional area of ​​the upper chamber 42 is larger than that of the lower chamber 43, a net downward force is generated, which causes the piston plate 41 to overcome the elastic force of the return spring 44 and press tightly against the inlet of the lower chamber 43, thus closing the main airflow channel. When a fire occurs, the pilot valve 33 opens instantly, and the high-pressure nitrogen in the pilot gas cylinder 31 is rapidly released through the pilot pipeline 32 and enters the upper chamber 42 through the connecting pipe 5. Then it is sprayed out from the vent of the pilot valve 33 and rushes towards the nearest fire extinguishing point. Due to the extremely fast release speed of the pilot gas flow, the pressure in the upper chamber 42 drops sharply. At this time, the lower chamber 43 still maintains a certain high pressure. The huge pressure difference generates an upward net force, which pushes the piston plate 41 to compress the spring 44 and move upward, thereby opening the main gas flow channel. A large amount of nitrogen in the main gas cylinder group then surges out and rushes through the opened channel to follow the pilot gas flow into the branch pipe 2, achieving full-area explosion suppression. Example 2

[0019] Reference Figures 1-4 As shown, further, it also includes a PLC-based controller 8. The temperature sensors 21 (which can be K-type thermocouples) on multiple branch pipes 2 are connected to the controller 8. The control valves 81 on multiple branch pipes 2 are also controlled by the controller 8. For example, when only the temperature sensor 21 at the mill part detects that the temperature exceeds the set threshold of 90°C, the controller 8 only activates the pilot control component 3 to perform global explosion suppression (the process is the same as in Embodiment 1). At the same time, the controller 8 only opens the control valves 81 on the branch pipes 2 at the mill part, while keeping the valves on other branch pipes 2 closed. In this way, most of the nitrogen released by the main gas cylinder group will be sprayed out from this branch pipe 2 and concentrated on extinguishing the fire at the mill part, thereby achieving precise spraying, saving gas, and avoiding unnecessary impact on other fire-free equipment.

[0020] Furthermore, a pressure gauge 9 is installed in the upper chamber. In order for the piston plate 41 to block the lower chamber, the pilot valve 33 on the pilot line 32 can be opened and the control valve 81 on the branch line 2 can be closed. This allows the airflow in the pilot line 32 to enter the piston chamber 7 and push the piston column 71 downward. The piston column 71 then pushes the piston plate 41 downward to block the lower chamber. By observing the pressure gauge 9, when the pressure reaches the set state, it indicates that the piston plate 41 has blocked the lower chamber.

Claims

1. A nitrogen fire extinguishing system for a coal mill, characterized in that, include; A nitrogen gas container unit, comprising multiple nitrogen cylinders (1), and the output ends of the multiple nitrogen cylinders (1) are connected to a main pipeline (11). Multiple branch pipes (2), the output ends of the multiple branch pipes (2) are respectively located at various flammable points in the coal mill, and each of the output ends of the multiple branch pipes (2) is equipped with a temperature sensor (21). The pilot control component (3) includes a pilot gas tank (31) containing nitrogen and a pilot pipeline (32) connected to the output end of the pilot gas tank (31). The pilot pipeline (32) is connected to multiple branch pipelines (2) through connecting pipelines, and a pilot valve (33) is provided on the pilot pipeline (32). The pilot gas tank (31) is configured such that when the pilot valve (33) is opened according to the fire signal, the high-pressure gas in it is released first through the pilot pipeline (32) to trigger the opening of the nitrogen holding unit and reach the extinguishing point before the main airflow of the nitrogen holding unit. The airflow distribution component is connected to the output end of the pilot pipeline (32) and the main pipeline (11) respectively, and is used to simultaneously open the nitrogen holding unit when the pilot control component (3) is depressurized.

2. The coal mill nitrogen fire extinguishing system according to claim 1, characterized in that, The airflow distribution assembly includes a distribution chamber (4) and a piston plate (41) located inside the distribution chamber (4). The piston plate (41) divides the distribution chamber (4) into an upper cavity (42) located above and a lower cavity (43) located below. A spring (44) is connected between the piston plate (41) and the lower cavity (43). A connecting pipe (5) is connected between the upper cavity (42) and the pilot guide (32). The cross-section of the upper cavity (42) is larger than the cross-section of the lower cavity (43), and the piston plate (41) is slidably and sealed inside the lower cavity (43).

3. The coal mill nitrogen fire extinguishing system according to claim 2, characterized in that, A telescopic guide rod (6) is connected between the piston plate (41) and the lower cavity (43) to guide the movement position of the piston plate (41).

4. The coal mill nitrogen fire extinguishing system according to claim 2, characterized in that, The upper cavity (42) is connected to a piston cavity (7) that is connected to the pilot guide circuit (32), and a piston column (71) extending to the outside of the piston cavity (7) is slidably connected inside the piston cavity (7) for abutting against the piston plate (41).

5. The coal mill nitrogen fire extinguishing system according to claim 1, characterized in that, It also includes a controller (8), and a control valve (81) is provided on the branch pipe (2). When the controller (8) receives a temperature sensor (21) on the corresponding branch pipe (2) and detects that the temperature exceeds the set range, it controls the corresponding control valve (81) to open.

6. The coal mill nitrogen fire extinguishing system according to claim 2, characterized in that, A pressure gauge (9) is installed inside the upper cavity (42).

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