Pneumatic sealing device for feeding end of overflow type coal mill

Abstract

The utility model relates to a pneumatic sealing device for a feeding end of an overflow type coal mill, and belongs to the technical field of feeding sealing of coal mills. The pneumatic sealing device comprises an annular air pipe, the annular air pipe is arranged at the feeding end of a feeding pipe of the coal mill in a sleeving mode, the annular air pipe is connected with an air supply pipe, and a plurality of air blowing pipes are evenly distributed on the side, facing a feeding port of the coal mill, of the annular air pipe. According to the pneumatic sealing device, air is blown to the feeding port of the coal mill through the annular air pipe, air seal is formed at the feeding port of the coal mill, and coal slurry is prevented from overflowing from the feeding port.

Description

Technical Field

[0001] The utility model relates to the technical field of coal mill feed seals, in particular to a pneumatic seal device at the feed end of an overflow type coal mill. Background Art

[0002] Coal mill is an important production equipment in the coal chemical industry. In recent years, the leakage of slurry at the feed port of the coal mill has become a problem that troubles the safe and stable operation of the system. At the same time, the leaked coal slurry accumulates at the bearing, which makes the hollow shaft of the coal mill always at risk of coal slurry infiltration. In order to prevent such accidents from happening again, the traditional method is to set flushing water at the feed port of the coal mill to flush the leaked coal slurry into the ditch in time. At the same time, in order to reduce the load of the mill and control the amount of leakage, the system adds a set of mills, and the coal slurry tank level is adjusted using a connecting valve. This mode of operation not only increases production costs and maintenance workload, but also increases process operation hazards (the connecting valve adjusts the level of the connected coal slurry tank and pays attention to the coal slurry flow rate and the rate of liquid level drop). Therefore, the leakage of slurry at the feed pipe of the coal mill has seriously restricted the stable operation of the system and equipment, and the on-site clean and civilized environment is also under great pressure. Thoroughly solving the leakage of coal mills is the main problem in stabilizing the operation of the system and improving the clean and civilized environment.

[0003] During the application process, a flange was installed on the end face of the mill and filled with wool felt for sealing. There was a certain effect in the initial stage, but it could not be maintained for a long period of time. After running for a period of time, the mill needed to be stopped for adjustment or the wool felt needed to be replaced. The reason was that during the operation of the mill, the centrifugal effect of the grinding rods made the mill cylinder always in a swinging state (swinging about 10mm left and right), causing the sealing wool felt to not always be close to the feed pipe. Coal slurry always seeped out with every rotation of the cylinder, so the leakage problem could not be solved.

[0004] During the long-term observation of mill operation and shutdown inspection, it was found that the main causes of slurry leakage at the mill inlet are: (1) During the operation of the mill, high-viscosity and high-concentration coal slurry adheres to the running cylinder wall and is lifted to the highest vertical point as the mill rotates, causing the coal slurry adhered to the cylinder wall to fall off and accumulate at the top of the feed pipe. As the coal slurry falls off, it gradually accumulates until it contacts the rotating end cover cylinder wall. Because the space at the mill feed inlet is conical in shape, a contact angle is formed that is small on the outside and large on the inside. As the mill rotates, the coal slurry adhered to the feed pipe and the cylinder wall is squeezed toward the inlet end. As the coal slurry continues to fall off and accumulate at the feed inlet, the rotating conical cylinder wall squeezes the coal slurry adhered to the feed pipe continuously along the feed pipe toward the inlet and discharges it, causing slurry leakage. This is also the fundamental reason why any simple external sealing device cannot completely solve the slurry leakage problem. (2) Some of the wall-hanging coal slurry flows along the inner wall of the end cover to the annular gap of the feed inlet and leaks out. Summary of the invention

[0005] In order to solve the problems in the prior art, the utility model patent designs a pneumatic sealing device at the feed end of an overflow coal mill to solve the problem that the existing treatment methods cannot stably prevent the leakage of coal slurry at the feed port of the coal mill.

[0006] The technical solution adopted by the utility model is: the pneumatic sealing device includes an annular air pipe, the annular air pipe is sleeved on the feed end of the feed pipe of the coal mill, the annular air pipe is connected to the air supply pipe, and a plurality of air blowing pipes are evenly distributed on the side thereof facing the feed port of the coal mill.

[0007] Furthermore, the pneumatic sealing device also includes an annular air chamber arranged at the coal mill inlet, and an annular baffle is arranged on the inner side of the end of the coal mill inlet along the end cover, and an annular air chamber is formed between the baffle and the end cover.

[0008] Furthermore, the baffle is arranged to be inclined toward the inner side of the feed inlet.

[0009] Furthermore, the annular air pipe is formed by butting two sections of semicircular branch pipes, and a fixing device is provided at the butt joint of the two sections of branch pipes.

[0010] Furthermore, both ends of one section of the branch pipe are provided with reduced-diameter plug connectors, and a sealing rubber ring is provided on the outer side of the plug connector.

[0011] Furthermore, the fixing device includes ear plates respectively arranged on the outer sides of both ends of the two branch pipes, and corresponding connecting holes are respectively opened on the ear plates of the two branch pipes, and are connected and fixed by bolts passing through the corresponding connecting holes.

[0012] Compared with the prior art, the improvement of the pneumatic sealing device at the feed end of an overflow type coal mill designed by the utility model patent lies in that: the annular air pipe forms a uniform injection airflow at the feed pipe of the coal mill feed port, and an annular air chamber is formed between the baffle and the end cover arranged at the feed port. The injected airflow enters the mill and is blocked by the baffle to produce vortex and diffusion. The airflows of each branch air pipe are evenly mixed in the air chamber to form an overall air mass and rush out from the annular gap of the air chamber, so that the coal slurry squeezed on the upper part of the feed pipe or the coal slurry flowing along the pipe wall to the annular gap of the baffle air chamber is blown away by the rushing airflow and re-enters the cylinder body, thereby achieving the purpose of sealing the annular gap between the feed pipe and the hollow shaft, solving the problems of overflow and on-site cleanliness and civilization, and eliminating hidden dangers in operation; the annular air pipe is formed by connecting two semicircular branch pipes, one of which is provided with a reducing plug joint, and corresponding ear plates are provided for connection and fixation, so that the annular air pipe can be quickly and conveniently disassembled and assembled. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the pneumatic sealing device at the feeding end of the overflow coal mill.

[0014] Figure 2It is a schematic diagram of the structure of the two branches that constitute the circular trachea.

[0015] In the figure, 1 is an annular air pipe, 2 is a baffle, 3 is an air supply pipe, 4 is an air blowing pipe, 5 is a feed pipe, 6 is an end cover, 11 is a branch pipe, 12 is a plug joint, 13 is a sealing rubber ring, 14 is an ear plate, 15 is a connecting hole, and 16 is a bolt. DETAILED DESCRIPTION

[0016] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments. The technical solutions in the embodiments of the utility model are clearly and completely described, and the described embodiments are only embodiments of a part of the invention, not all of it. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0017] like Figure 1 , 2 As shown, the utility model patent designs an embodiment of a pneumatic sealing device at the feed end of an overflow type coal mill. In this embodiment, the pneumatic sealing device includes an annular air pipe 1, which is sleeved on the feed end of the feed pipe 5 of the coal mill. An air supply pipe 3 is connected to the annular air pipe 1, and a plurality of air blowing pipes 4 are evenly distributed on the side thereof facing the feed port of the coal mill. The air supply pipe 3 is connected to an external high-pressure air source.

[0018] The annular air pipe 1 is formed by butting two semicircular branch pipes 11, wherein both ends of one branch pipe 11 are provided with a plug joint 12 with a reduced diameter, and a sealing rubber ring 13 is sleeved on the outer side of the plug joint 12. A fixing device is provided at the butt joint of the two branch pipes 11, and the fixing device is composed of ear plates 14 provided on the outer sides of both ends of the two branch pipes 11, and corresponding connecting holes 15 are respectively opened on the ear plates 14 of the two sections of the branch pipes 11, and bolts 16 are passed through the corresponding connecting holes 15 to connect and fix.

[0019] At the coal mill inlet, a circle of annular baffles 2 is welded along the inner side of the end cover 6 near the end. The baffles 2 are inclined toward the inner side of the inlet, and an annular air chamber is formed between the baffles 2 and the end cover 6.

[0020] When the pneumatic sealing device at the feed end of the overflow type coal mill disclosed in the utility model patent is used, the air compressor supplies air to the annular air pipe 1 through the air supply pipe 3, and the blowing pipes 4 evenly arranged and connected to the annular air pipe 1 blow out high-pressure airflow to the feed port of the coal mill, and the high-pressure airflow enters the air chamber along the annular gap between the feed pipe 5 and the feed port end cover 6 of the coal mill. Under the action of the baffle 2, the high-pressure airflow is mixed into a uniform air mass in the air chamber, and the coal slurry squeezed on the upper part of the feed pipe or the coal slurry flowing along the wall to the annular gap of the baffle air chamber is blown away and re-entered into the cylinder, thereby achieving the purpose of sealing the annular gap between the feed pipe and the hollow shaft, solving the problems of coal slurry overflow and on-site cleanliness and civilization, and eliminating operating hazards.

[0021] The above contents are only preferred embodiments of the present invention and cannot be used to limit the scope of implementation of the present invention. That is, any simple equivalent changes and modifications made according to the claims and description of the present invention are still within the scope of the present invention.

Claims

1. A pneumatic sealing device for the feeding end of an overflow coal mill, characterized in that: The pneumatic sealing device comprises an annular air pipe, which is sleeved on the feed end of the feed pipe of the coal mill, is connected to an air supply pipe, and has a plurality of air blowing pipes evenly distributed on the side of the annular air pipe facing the feed port of the coal mill; The pneumatic sealing device also includes an annular air chamber arranged at the coal mill inlet. An annular baffle is arranged on the inner side of the end of the coal mill inlet along the end cover, and an annular air chamber is formed between the baffle and the end cover.

2. The pneumatic sealing device for the feeding end of an overflow coal mill according to claim 1, characterized in that: The baffle is arranged to be inclined toward the inner side of the feed inlet.

3. The pneumatic sealing device at the inlet end of an overflow coal mill according to claim 2, characterized in that: The annular air pipe is formed by butting two sections of semicircular branch pipes, and a fixing device is arranged at the butt joint of the two sections of branch pipes.

4. The pneumatic sealing device for the feeding end of an overflow coal mill according to claim 3, characterized in that: Both ends of one section of the branch pipe are provided with reduced-diameter plug connectors, and a sealing rubber ring is provided on the outer side of the plug connector.

5. The pneumatic sealing device for the feeding end of an overflow coal mill according to claim 4, characterized in that: The fixing device comprises ear plates respectively arranged on the outer sides of both ends of the two branch pipes, the ear plates of the two branch pipes are respectively provided with corresponding connection holes, and are connected and fixed by bolts passing through the corresponding connection holes.

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