A measuring tube suitable for 600MW unit coal mill powder level monitoring

Abstract

This invention relates to a measuring tube for monitoring the coal level in a 600MW coal mill, comprising a grinding device, an upper measuring tube, and a lower measuring tube. Feeding and discharging devices are respectively installed on both sides of the grinding device. The upper and lower measuring tubes are arranged side-by-side above the feeding and discharging devices. Both the upper and lower measuring tubes include an air inlet and a monitoring end. The monitoring end of both the upper and lower measuring tubes extends into the grinding device. The monitoring end of the lower measuring tube, located within the grinding device, extends downwards along the edge of the connection between the feeding and discharging devices and the grinding device to the bottom of the grinding device. In this application, the lower measuring tube is positioned above the outer casing and extends directly into the grinding tank. The trajectory of the lower measuring tube has been adjusted to avoid wear while maintaining its original monitoring function, effectively solving the problem of wear on the measuring tube caused by the current coal mill auger conveying raw coal.

Description

Technical Field

[0001] This invention belongs to the field of ball mill equipment, and specifically relates to a measuring tube suitable for monitoring the powder level in a 600MW unit coal mill. Background Technology

[0002] The powder level monitoring inside the tank of a double-inlet double-outlet ball mill (hereinafter referred to as the mill) is one of the important indicators for adjusting the coal feeder and controlling the output of the mill. Inaccurate powder level measurement has a significant impact on the mill's autonomous adjustment of the coal feeder, and indirectly affects the unit's load regulation.

[0003] The monitoring of the powder level inside the coal mill tank mainly relies on the powder level measuring tube and the powder level measuring control system. The measuring tube needs to extend from the outside of the tank to the inside of the tank, and there are two measuring points at the top and bottom of the tank.

[0004] When the auger in the coal mill transports raw coal, it will cause wear to the guard plates around the auger, especially the guard plate below the auger. With the long-term operation of the coal mill, this will affect the measuring tube below the guard plate, causing the measuring tube to wear and leak, resulting in inaccuracy. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a measuring tube suitable for monitoring the coal level in a 600MW unit coal mill, so as to solve the problem of wear on the measuring tube when the screw conveyor transports raw coal in the coal mill.

[0006] To solve the above problems, the present invention adopts the following technical solution:

[0007] A measuring tube for monitoring the pulverized coal level in a 600MW unit coal mill includes a grinding device. Feeding and discharging devices are respectively installed on both sides of the grinding device. An upper measuring tube is installed on each feeding and discharging device. The upper measuring tube includes an air inlet end and a measuring end. The measuring end of the upper measuring tube extends into the grinding device. A lower measuring tube with the same structure is installed on one side of the upper measuring tube. The measuring end of the lower measuring tube extends into the grinding device and extends along the connection between the feeding / discharging device and the grinding device to the bottom of the grinding device.

[0008] Furthermore, the monitoring ends of both the upper and lower measuring tubes located inside the grinding device are sealed, and monitoring holes are opened on the outer circumferential surfaces of both the upper and lower measuring tubes located inside the grinding device.

[0009] Furthermore, the diameter of the monitoring hole gradually decreases from the inside to the outside.

[0010] Furthermore, the grinding device includes a grinding jar and a drive motor. A driven gear ring is arranged around the outer circumference of the grinding jar. A transmission gear is provided on the output shaft of the drive motor. The transmission gear and the driven gear ring are meshed and connected. The grinding jar is arranged horizontally and has feed ports at both ends. Steel balls are provided inside the grinding jar. The feed ports are rotatably connected to the feeding and discharging devices respectively.

[0011] Furthermore, the diameters at both ends of the grinding jar gradually decrease.

[0012] Furthermore, the feeding and discharging device includes a coal inlet / outlet channel and a conveying auger. The conveying auger includes a feeding auger and a shell. A support is provided at the bottom of the shell. A cylindrical guard plate is coaxially arranged inside the shell. The two ends of the guard plate are connected to the two ends of the shell. The coal inlet / outlet channel is located at the upper end of the shell and communicates with the inside of the guard plate. The upper and lower measuring tubes are both located between the guard plate and the shell. The monitoring end of the lower measuring tube extends in an arc along the outer circumference of the guard plate to the bottom of the grinding jar. The outer circumference of the first end of the shell is rotatably connected to the inner wall of the feed inlet. The guard plate communicates with the inside of the grinding jar. The feeding auger is located inside the guard plate. The feeding auger, the shell, and the feed inlet are coaxially arranged.

[0013] Furthermore, the feeding auger includes a hollow shaft and spiral blades. The spiral blades are mounted on the hollow shaft with the hollow shaft as the axis. The first end of the hollow shaft extends into the grinding jar. The outer circumference of the first end of the hollow shaft is provided with a fixing rod that is fixedly connected to the inner wall of the grinding jar. The second end of the hollow shaft is rotatably connected to the inner wall of the guard plate. An air inlet communicating with the second end of the hollow shaft is provided on the outer side of the second end of the outer shell.

[0014] The significant beneficial effects achieved by this invention are as follows:

[0015] 1. This invention provides a measuring tube for monitoring the coal level in a 600MW coal mill, comprising a grinding device, an upper measuring tube, and a lower measuring tube. Feeding and discharging devices are respectively installed on both sides of the grinding device. The upper and lower measuring tubes are arranged side-by-side above the feeding and discharging devices. Both the upper and lower measuring tubes include an air inlet and a monitoring end. The monitoring end of both the upper and lower measuring tubes extends into the grinding device. The monitoring end of the lower measuring tube, located within the grinding device, extends downwards along the connection between the feeding and discharging devices and the grinding device to the bottom of the grinding device. In this application, the lower measuring tube is positioned above the outer casing and extends directly into the grinding tank. The trajectory of the lower measuring tube has been adjusted to avoid wear while maintaining its original monitoring function, effectively solving the problem of wear on the measuring tube caused by the current coal mill auger conveying raw coal.

[0016] 2. The closed monitoring ends of both the upper and lower measuring tubes can prevent a large amount of coal dust from entering and causing blockage. The opening of the monitoring hole can reduce the amount of coal dust entering without affecting the monitoring effect. The inner diameter of the monitoring hole is larger inside and smaller outside, which can prevent coal dust from clogging the monitoring hole. After entering the monitoring hole, the coal dust will fall directly into the tube along the gradually increasing inner diameter, which can effectively slow down the time for blockage to form.

[0017] 3. The grinding device is designed to grind the incoming raw coal. The gradually decreasing diameter at both ends of the grinding tank allows the raw coal to be ground to be concentrated in the middle of the grinding tank for centralized grinding, which improves grinding efficiency and protects the upper and lower measuring tubes entering the grinding tank.

[0018] 4. The inlet and outlet channels in the feeding and discharging device are used to allow raw coal to enter and coal powder to leave. The conveying auger is used to convey raw coal and blow out coal powder. The outer shell of the conveying auger is used to connect to the grinding jar and facilitate the extension of the upper and lower measuring tubes into the grinding jar.

[0019] 5. The feeding auger with a hollow shaft allows for the simultaneous discharge of pulverized coal from both inlet and outlet channels, increasing discharge speed and practicality. Attached Figure Description

[0020] Appendix Figure 1 This is a schematic diagram of the main view structure of the measuring tube for monitoring the coal mill level in a 600MW unit, according to Embodiment 1 of the present invention.

[0021] Appendix Figure 2 This is a schematic cross-sectional view of the measuring tube structure for monitoring coal mill powder level in a 600MW unit, according to Embodiment 1 of the present invention.

[0022] Appendix Figure 3 This is a schematic diagram of the right-side cross-sectional structure of the grinding tank in the measuring tube for monitoring the coal level in a 600MW unit coal mill, according to Embodiment 1 of the present invention.

[0023] Appendix Figure 4 This is a schematic diagram of the main view structure of the measuring tube for monitoring the coal mill level in a 600MW unit, according to Embodiment 2 of the present invention.

[0024] Appendix Figure 5 This is a schematic cross-sectional view of the measuring tube structure for monitoring coal mill powder level in a 600MW unit, according to Embodiment 2 of the present invention.

[0025] Appendix Figure 6 This is a schematic diagram of the right-side cross-sectional structure of the grinding tank in the measuring tube for monitoring the coal pulverizer level in a 600MW unit, according to Embodiment 2 of the present invention.

[0026] Appendix Figure 7 This is a cross-sectional view of the monitoring end of the upper or lower measuring tube in the measuring tube for monitoring the coal level in a 600MW unit coal mill, according to Embodiment 3 of the present invention.

[0027] In the attached drawings, 1-grinding device, 2-feeding and discharging device, 3-upper measuring tube, 4-lower measuring tube, 5-monitoring hole, 6-grinding jar, 7-drive motor, 8-driven gear ring, 9-transmission gear, 61-steel ball, 10-coal inlet and outlet channel, 11-feeding auger, 12-outer shell, 121-support component, 13-guard plate, 14-hollow shaft, 15-spiral blade, 16-fixed rod, 17-air inlet, 18-powder level monitoring device, 19-feed inlet, 20-sealed bearing. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0029] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0030] Example 1

[0031] like Figure 1 , Figure 2 and Figure 3 As shown, a measuring tube suitable for monitoring the powder level of a 600MW unit coal mill includes a grinding device 1, a feeding and discharging device 2, an upper measuring tube 3, and a lower measuring tube 4. There are two feeding and discharging devices 2, which are respectively arranged on both sides of the grinding device 1. The upper measuring tube 3 and the lower measuring tube 4 are arranged side by side above the feeding and discharging device 2. Both the upper measuring tube 3 and the lower measuring tube 4 include an air inlet end and a monitoring end. The air inlet end of the upper measuring tube and the air inlet end of the lower measuring tube 4 are respectively connected to the powder level monitoring device 18. The monitoring end of the upper measuring tube 3 and the monitoring end of the lower measuring tube 4 extend into the grinding device 1. The monitoring end of the lower measuring tube 4 located in the grinding device 1 extends downward along the connection between the feeding and discharging device 2 and the grinding device 1 to the bottom of the grinding device 1.

[0032] The monitoring ends of the upper measuring tube 3 and the lower measuring tube 4 are both closed. The outer circumference of the upper measuring tube 3 and the lower measuring tube 4 located inside the grinding device 1 are all surrounded by monitoring holes 5. There are six monitoring holes 5, which are evenly distributed. The upper measuring tube 3 and the lower measuring tube 4 are used to monitor the amount of coal powder in the grinding device 1. When in use, the air inlet end of the upper measuring tube 3 and the lower measuring tube 4 located outside the grinding device 1 is connected to the coal powder level measurement and monitoring device 18. The coal powder level measurement and monitoring device 18 determines the coal powder level in the grinding device 1 by blowing air of a certain pressure ratio into the upper measuring tube 3 and the lower measuring tube 4 and based on the feedback results. The coal powder level measurement and monitoring device 18 is existing technology and will not be described in detail here.

[0033] The grinding device 1 includes a grinding jar 6 and a drive motor 7. The grinding jar 6 is arranged horizontally and has circular feed ports 19 at both ends. The diameter of the grinding jar 6 gradually decreases at both ends. The grinding jar 6 is filled with steel balls 61. There are two feed ports 19, which are rotatably connected to the feeding and discharging devices 2 located on both sides of the grinding device 1. A driven gear ring 8 is arranged around the outer circumference of the grinding jar 6. A transmission gear 9 is installed on the output shaft of the drive motor 7. The transmission gear 9 and the driven gear ring 8 mesh. When the drive motor 7 is started, the grinding jar 6 is rotated by the meshing connection between the transmission gear 9 and the driven gear ring 8. The inner wall of the grinding jar 6 is generally provided with wavy or trapezoidal protrusions. The rotation of the grinding jar 6 will cause the steel balls 61 inside to move and collide continuously, turning the coal into powder. The gradually decreasing diameter at both ends of the grinding jar 6 can gather the steel balls 61 and raw coal in the middle of the grinding jar 6 for easy grinding, and at the same time, it can protect the monitoring end of the measuring tube 4 located at the bottom of the grinding jar 6.

[0034] The feeding / discharging device 2 includes a coal inlet / outlet channel 10 and a conveying auger. The conveying auger includes a feeding auger 11 and a housing 12. The housing 12 is arranged horizontally and has a support member 121 at the bottom for supporting the housing 12. A cylindrical guard plate 13 is coaxially installed inside the housing 12. The coal inlet / outlet channel 10 is vertically installed on the upper part of the housing 12 and communicates with the guard plate 13. The two ends of the housing 12 are connected to the two ends of the guard plate 13 to seal the gap between the housing 12 and the guard plate 13. The upper measuring tube 3 and the lower measuring tube 4 are both located between the housing 12 and the guard plate 13 and are located above the guard plate 13. The air inlet ends of the upper measuring tube 3 and the lower measuring tube 4 extend upward to the outside of the housing and are connected to the powder level monitoring device 18. The measuring ends of the upper measuring tube 3 and the lower measuring tube 4 extend into the grinding tank 6. The lower measuring tube 4 extends into the grinding tank 6. The measuring end extends in an arc along the outer periphery of the guard plate 13 to the bottom of the grinding tank 6. The outer periphery of the first end of the outer shell 12 is rotatably connected to the inner wall of the feed inlet 19 through a sealed bearing 20. The guard plate 13 and the inside of the grinding tank 6 are connected. The feeding auger 11 is installed inside the guard plate 13. The feeding auger 11, the outer shell 12 and the feed inlet 19 are coaxially arranged. In this embodiment, the feeding auger 11 is a screw conveyor. The coal inlet and outlet channel 10 is used to feed raw coal and discharge coal powder. When coal is fed, the raw coal falls into the outer shell 12 along the coal inlet and outlet channel 10. The feeding auger 11 opens to send the raw coal in the outer shell 12 to the grinding tank 6 through the feed inlet 19 for grinding. After the raw coal is ground into coal powder, the coal powder in the grinding tank 6 is discharged from the other side of the coal inlet and outlet channel 10 for collection by air intake from the coal inlet and outlet channel 10 on one side of the grinding tank 6.

[0035] Working principle: When raw coal needs to be ground, the raw coal is fed into the guard plate 13 from the coal inlet and outlet channels 10 on both sides of the grinding tank 6. The feeding auger 11 feeds the raw coal into the grinding tank 6 by rotating. The drive motor 7 is turned on to drive the grinding tank 6 to rotate, which causes the multiple steel balls 61 in the grinding tank 6 to move and collide with each other to complete the crushing and grinding of the raw coal. After the coal powder level monitoring device 18 detects that the amount of coal powder in the grinding tank 6 has reached the required amount through the upper measuring tube 3 and the lower measuring tube 4, air is blown from the coal inlet and outlet channel 10 on one side of the grinding tank 6. The airflow passes through the grinding tank 6 and is discharged from the coal inlet and outlet channel 10 on the other side of the grinding tank 6. When the airflow passes through the grinding tank 6, it will carry the coal powder out at the same time, thus completing the removal of the coal powder.

[0036] Workers can install a dust collector at the exit of the coal inlet / outlet 10 on the other side to collect coal dust, which will not be elaborated here.

[0037] In summary, this application places the lower measuring tube 4 above the outer casing 12 and extends the monitoring end of the lower measuring tube 4 directly into the bottom of the grinding tank 6 in an arc shape along the first end of the arc-shaped pipe. The position and trajectory of the lower measuring tube 4 have been adjusted so that it can avoid the predicament of being worn while maintaining the original monitoring function. This effectively solves the problem of wear on the measuring tube when the coal mill auger is conveying raw coal, and avoids the situation where the measuring tube is worn and leaks, resulting in inaccuracy.

[0038] Example 2

[0039] like Figure 4 Diagram and Figure 6 As shown, the structure of this embodiment is roughly the same as that of Embodiment 1. This embodiment is further optimized based on Embodiment 1. In this embodiment, the feeding auger 11 includes a hollow shaft 14 and a spiral blade 15. The spiral blade 15 is fixedly connected to the outer circumference of the hollow shaft 14. The first end of the hollow shaft 14 extends into the grinding tank 6. A fixing rod 16, which is fixedly connected to the inner wall of the grinding tank 6, is installed around the outer circumference of the first end of the hollow shaft 14. There are six fixing rods 16. The second end of the hollow shaft 14 is rotatably connected to the inner wall of the guard plate 13 through a bearing. An air inlet 17 communicating with the second end of the hollow shaft 14 is installed on the outer shell 12. The fixing rods 16 can drive the hollow shaft 14 to rotate synchronously when the grinding tank 6 rotates, which facilitates the conveying of raw coal by the hollow shaft 14. At the same time, it can reduce the power unit and make the overall equipment simpler.

[0040] The working principle is as follows: when it is necessary to remove the ground coal powder, air is blown in through the air inlets 17 of the two outer shells 12. The air entering the grinding tank 6 from the air inlets 17 on both sides collides with each other inside the grinding tank 6. The air after the collision is discharged from the coal inlet and outlet channels 10 on both sides of the grinding tank 6 through the gap between the hollow shaft 14 and the discharge port and the gap between the hollow shaft 14 and the outer shell 12. When the air flows, the grinding tank 6 rotates continuously to facilitate the airflow to carry out the coal powder. The workers can then collect the coal powder discharged from the coal inlet and outlet channels 10.

[0041] Example 3

[0042] like Figure 7 As shown, the structure of this embodiment is roughly the same as that of embodiment 2. This embodiment is further optimized based on embodiment 2. In order to avoid the monitoring holes 5 on the monitoring ends of the lower measuring tube 4 and the upper measuring tube 3 from being blocked, the diameter of the monitoring hole 5 gradually decreases from the inside to the outside. By making the diameter of the monitoring hole 5 larger inside and smaller outside, the speed at which coal powder blocks the monitoring hole 5 can be slowed down.

[0043] Currently, the technical solution of this application has undergone pilot testing, which is a small-scale experiment before the product is mass-produced. After the pilot testing was completed, a user survey was conducted on a small scale, and the survey results showed that user satisfaction was high. Now, preparations have begun for the formal production and industrialization of the product (including intellectual property risk warning surveys).

Claims

1. A measuring tube for monitoring the pulverized coal level in a 600MW unit coal mill, comprising a grinding device (1), wherein feeding and discharging devices (2) are respectively provided on both sides of the grinding device (1), and an upper measuring tube (3) is provided on each feeding and discharging device (2), wherein the upper measuring tube (3) includes an air inlet end and a measuring end, and the monitoring end of the upper measuring tube (3) extends into the grinding device (1), characterized in that: A lower measuring tube (4) with the same structure is provided on one side of the upper measuring tube (3). The monitoring end of the lower measuring tube (4) extends into the grinding device (1). The monitoring end of the lower measuring tube (4) extends in an arc shape along the connection between the feeding and discharging device (2) and the grinding device (1) to the bottom of the grinding device (1). The monitoring ends of the upper measuring tube (3) and the lower measuring tube (4) located inside the grinding device (1) are both closed, and monitoring holes (5) are opened on the outer peripheral surfaces of the upper measuring tube (3) and the lower measuring tube (4) located inside the grinding device (1); the diameter of the monitoring hole (5) gradually decreases from the inside to the outside. The grinding device (1) includes a grinding jar (6), which is arranged horizontally and has feed inlets (19) at both ends. The feeding and discharging device (2) includes a coal inlet / outlet channel (10) and a conveying auger. The conveying auger includes a feeding auger (11) and a housing (12). A support member (121) is provided at the bottom of the housing (12). A cylindrical guard plate (13) is coaxially provided inside the housing (12). The two ends of the guard plate (13) are connected to the two ends of the housing (12). The coal inlet / outlet channel (10) is located at the upper end of the housing (12) and communicates with the inside of the guard plate (13). The upper measuring tube (3) and the lower measuring tube (3) are connected to the coal inlet / outlet channel (10). 4) Both are set between the guard plate (13) and the outer shell (12). The monitoring end of the lower measuring tube (4) extends in an arc along the outer circumference of the guard plate (13) to the bottom of the grinding tank (6). The outer circumference of the first end of the outer shell (12) is rotatably connected to the inner wall of the feed port (19). The guard plate (13) and the grinding tank (6) are connected. The feeding auger (11) is set inside the guard plate (13). The feeding auger (11), the outer shell (12) and the feed port (19) are coaxially arranged.

2. The measuring tube for monitoring the pulverized coal level in a 600MW unit coal mill according to claim 1, characterized in that: The grinding device (1) also includes a drive motor (7), a driven gear ring (8) is provided around the outer circumference of the grinding tank (6), a transmission gear (9) is provided on the output shaft of the drive motor (7), the transmission gear (9) and the driven gear ring (8) mesh with each other, a steel ball (61) is provided inside the grinding tank (6), and the feed port (19) is rotatably connected to the feeding and discharging device (2).

3. A measuring tube for monitoring the pulverized coal level in a 600MW unit coal mill, as described in claim 2, is characterized in that: The diameters of the two ends of the grinding jar (6) gradually decrease.

4. A measuring tube for monitoring the pulverized coal level in a 600MW unit coal mill, as described in claim 3, is characterized in that: The feeding auger (11) includes a hollow shaft (14) and a spiral blade (15). The spiral blade (15) is mounted on the hollow shaft (14) with the hollow shaft (14) as the axis. The first end of the hollow shaft (14) extends into the grinding jar (6). The outer circumference of the first end of the hollow shaft (14) is provided with a fixing rod (16) that is fixedly connected to the inner wall of the grinding jar (6). The second end of the hollow shaft (14) is rotatably connected to the inner wall of the guard plate (13). The outer side of the second end of the outer shell (12) is provided with an air inlet (17) that communicates with the second end of the hollow shaft (14).

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