Polishing device suitable for common urea

Abstract

The utility model relates to a polishing device suitable for common urea. Comprising a polishing roller body, a lifting unit used for lifting the polishing roller body is arranged at the bottom of the polishing roller body, a supporting power unit used for supporting and rotating the polishing roller body is arranged on the upper portion of the lifting unit, a urea inlet is formed in one end of the polishing roller body, and a urea outlet is formed in the other end of the polishing roller body. A polishing treatment area, a polishing area and a cooling area are sequentially arranged in the portion, between the urea inlet and the urea outlet, of the polishing roller body. A steam polishing liquid input unit is arranged in the polishing treatment area; the problem that urea subjected to primary granulation is not suitable for coating due to poor roundness can be solved, and the characteristics of continuous operation, efficiency improvement and energy consumption reduction can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of urea coating, in particular to a polishing device suitable for common urea. Background Art

[0002] Coated urea is produced by coating a thin film on the surface of ordinary urea to reduce the nutrient release rate of urea, thereby achieving the purpose of efficient utilization of nitrogen sources. In the production process, the roundness of ordinary urea has a great influence on the nutrient release of coated urea. Low particle roundness will make the nutrient release rate of coated urea worse, causing the nutrient release of urea to be too fast in the early stage of production, resulting in poor growth of crops due to lack of fertilizer in the later stage. Therefore, it is extremely important to control the roundness of raw material particles in the production process.

[0003] At present, the main means of controlling the roundness of particles is to use ordinary large-particle urea produced by secondary granulation. The advantages of large-particle urea produced by secondary granulation are high particle roundness and smooth surface, which are suitable for the production of coated urea; but its disadvantage is that the production capacity is small, and its output as a raw material for coated urea is very limited. For this reason, most coated urea manufacturers also use urea produced by primary granulation as the core of coated urea production, but the roundness of urea produced by primary granulation is poor, resulting in poor roundness of coated urea, which seriously affects the quality of the product.

[0004] Based on the above problems, how to realize the production of urea by one-time granulation as the core of coated urea production and improve the roundness of coated urea has become a technical problem that needs to be solved urgently. Utility Model Content

[0005] The purpose of the utility model is to provide a polishing device suitable for common urea to solve the problems raised in the above background technology.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A polishing device suitable for common urea comprises a polishing drum body, a lifting unit for lifting the polishing drum body is provided at the bottom of the polishing drum body, a supporting power unit for supporting and rotating the polishing drum body is provided at the top of the lifting unit, a urea inlet is provided at one end of the polishing drum body, a urea outlet is provided at the other end, and a polishing treatment area, a polishing area and a cooling area are arranged in sequence in the polishing drum body between the urea inlet and the urea outlet; a steam polishing liquid input unit is provided in the polishing treatment area.

[0008] The beneficial effects of the utility model are as follows: by arranging a steam polishing liquid input unit, steam and polishing liquid can be input into the polishing treatment area, and by inputting steam, the temperature in the polishing treatment area can be controlled to soften the surface of the urea particles; after the polishing liquid and the urea particles are fully mixed, the urea particles can be further softened; the above two methods can improve the polishing effect by softening the urea, and at the same time, by arranging a lifting unit, the residence time of the urea particles in the polishing drum body can be increased, thereby achieving the improvement of the polishing effect of the urea particles, and the urea produced by one-time granulation is used as the production core of the coated urea on the premise of ensuring the roundness (quality) of the coated urea.

[0009] Furthermore, the steam polishing liquid input unit includes a steam polishing liquid input pipeline, a nozzle is provided in the steam polishing liquid input pipeline inside the polishing treatment area, and the steam polishing liquid input pipeline outside the polishing treatment area is respectively connected to the steam system and the polishing liquid storage tank.

[0010] Furthermore, the lifting unit includes a movable part and a lifting part, the movable part includes a lifting seat arranged at the lower part of one end of the polishing drum body, and the top of the lifting seat is hingedly connected to the bottom of the supporting power unit; the lifting part includes a lifting member arranged at the lower part of the other end of the polishing drum body, and the movable end of the lifting member is hingedly connected to the bottom of the supporting power unit; the lifting member is a hydraulic cylinder.

[0011] Furthermore, the supporting power unit includes a supporting seat with a bottom and connected to the top of the lifting seat and the movable end of the lifting member respectively, polishing roller brackets are respectively provided at both ends of the top of the supporting seat, and a driving member and a driven member are provided between the polishing roller brackets; the driving member includes a driving motor, the shaft of the driving motor is connected to the shaft with a driving gear through a reducer, and the driving gear is meshed with a driving gear ring arranged on the outer circumference of the polishing roller body; the driven member includes a driven gear arranged on the support, and the driven gear is meshed with a driven gear ring arranged on the outer circumference of the polishing roller body.

[0012] Furthermore, automatic retaining ring units are respectively provided between the polishing treatment area and the polishing area, and between the polishing area and the cooling area.

[0013] Furthermore, the automatic retaining ring unit includes a fixed retaining ring and a movable retaining ring, which are cross-arranged, the fixed retaining ring is fixedly connected to the inner wall of the polishing drum body, and the movable retaining ring is connected to the adjacent side of the fixed retaining ring through a pull-rod type expansion joint; a main shaft is provided in the polishing drum body, and a shaft seal is provided on the main shaft. The shaft seal includes a fixed shaft seal sleeved on the main shaft and a movable shaft seal rotating with the polishing drum body, and the power branch line of the pull-rod type expansion joint is connected to the power main line arranged on the fixed shaft seal through the movable shaft seal.

[0014] Furthermore, there are four fixed retaining rings and four movable retaining rings, and the four power branch lines are respectively connected to the power main line; the pull-rod telescope is an electric pull-rod telescope, a hydraulic pull-rod telescope or a pneumatic pull-rod telescope; when the pull-rod telescope is an electric pull-rod telescope, the power branch line and the power main line are power lines; when the pull-rod telescope is a hydraulic pull-rod telescope, the power branch line and the power main line are hydraulic oil lines; when the pull-rod telescope is a pneumatic pull-rod telescope, the power branch line and the power main line are air lines.

[0015] Furthermore, the pull rod type expansion joint is arranged at a middle position on one side of the fixed retaining ring, and hinges are respectively arranged on the corresponding fixed retaining rings at the upper and lower parts of the pull rod type expansion joint.

[0016] Furthermore, the polishing area, the polishing area and the cooling area are respectively provided with a copying plate part; the copying plate part of the polishing area is an L-shaped copying plate, and the copying plate parts of the polishing area and the cooling area are conical copying plates.

[0017] According to the above scheme, a polishing device suitable for ordinary urea is made. By setting a lifting unit, the residence time of urea particles in the polishing drum body can be increased, so as to improve the polishing effect of urea particles. Further, by setting a steam polishing liquid input unit, the temperature in the polishing treatment area can be increased and the polishing liquid can be sprayed on the urea particles to soften the surface of the urea particles. The combination of the above two can realize the coating of urea particles produced by one granulation, and has the advantages of good roundness to ensure the quality of coated urea. The utility model is provided with automatic retaining ring units at both ends of the polishing area. The lifting unit can realize the characteristics of long-term polishing of urea particles in the polishing area, and can avoid the flow of urea particles in different areas, which affects the overall roundness of urea particles. Further, the utility model is provided with different copying plate parts in different areas. The L-shaped copying plate can realize the urea particles in the drum in a raised state, increase the contact between the polishing liquid and the particles; the conical copying plate can realize the urea particles in the drum in a rolling state, so as to achieve the advantage of improving the urea polishing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the automatic retaining ring unit of the utility model;

[0020] Figure 3 This is a schematic diagram of the positional relationship between the main shaft and the shaft seal of the utility model;

[0021] Figure 4 It is a schematic diagram of the plate copying part of the polishing treatment area, the polishing area and the cooling area of ​​the utility model.

[0022] Figure 5 This is a schematic diagram of the structure of the L-shaped copy board in the polishing treatment area of ​​the utility model;

[0023] Figure 6 It is a schematic diagram of the structure of the conical copying plate in the polishing area of ​​the utility model.

[0024] Legend:

[0025] 1. Polishing drum body; 2. Steam polishing liquid input pipeline; 3. Nozzle; 4. Steam system; 5. Polishing liquid storage tank; 6. Lifting seat; 7. Lifting parts; 8. Support seat; 9. Polishing drum bracket; 10. Driving motor; 11. Reducer; 12. Driving gear; 13. Driving gear ring; 14. Support; 15. Driven gear; 16. Driven gear ring; 17. Fixed retaining ring; 18. Movable retaining ring; 19. Pull rod type expansion joint; 20. Main shaft; 21. Hinge; 22. L-type copying plate; 23. Fixed shaft seal; 24. Conical copying plate; 25. Movable shaft seal; 26. Power main line; 27. Power branch line. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] Reference Figure 1-6The utility model provides a polishing device suitable for ordinary urea, which includes a polishing drum body 1. The bottom of the polishing drum body 1 is provided with a lifting unit for realizing the lifting of the polishing drum body 1. The upper part of the lifting unit is provided with a supporting power unit for supporting and rotating the polishing drum body 1. One end of the polishing drum body 1 is provided with a urea inlet, and the other end is provided with a urea outlet. The polishing drum body 1 between the urea inlet and the urea outlet is sequentially provided with a polishing treatment area, a polishing area and a cooling area; the polishing treatment area is provided with a steam polishing liquid input unit. The utility model is a transformation of an existing polishing drum, that is, based on the existing polishing drum, a lifting unit is provided to change the angle of the polishing drum body 1, and a steam polishing liquid input unit is provided in the polishing treatment area, and steam and polishing liquid are input into the polishing treatment area to improve the softening degree of the surface of urea particles from the perspective of temperature and the properties of the polishing liquid itself, and the lifting unit is cooperated to realize long-term polishing of urea particles, thereby polishing the primary granulated urea to improve the roundness of its surface, and realizing the characteristic of using the primary granulated urea as the core to prepare coated urea; the main purpose of the lifting unit is to change the angle of the polishing drum body 1 and increase the residence time of the urea particles in the polishing drum body 1, and preferably, the lifting part of the lifting unit is arranged at the end of the polishing drum body 1.

[0028] Furthermore, the steam polishing liquid input unit includes a steam polishing liquid input pipeline 2, a nozzle 3 is provided in the steam polishing liquid input pipeline 2 inside the polishing treatment area, and the steam polishing liquid input pipeline 2 outside the polishing treatment area is respectively connected to the steam system 4 and the polishing liquid storage tank 5. The steam polishing liquid input pipeline 2 is a dual-purpose pipe, one of which can pass steam into the polishing drum body 1, so that the temperature of the polishing treatment area is controlled at 60-120°C, so that the surface of the urea particles is softened, which is conducive to increasing the roundness of the particle surface in the later polishing process; the second is to spray 0-10% of the polishing liquid into the polishing treatment area to soften the surface of the urea particles so as to achieve the purpose of being easier to polish; in the actual production process, steam and polishing liquid are used alternately, and the steam volume is controlled by the temperature control system (or the temperature sensor with the valve) so that the inside of the polishing treatment area is within the set temperature range, and after the temperature is stable, the polishing liquid is sprayed intermittently.

[0029] Further, the lifting unit includes a movable part and a lifting part, the movable part includes a lifting seat 6 arranged at the lower part of one end of the polishing drum body 1, and the top of the lifting seat is hingedly connected to the bottom of the supporting power unit; the lifting part includes a lifting member 7 arranged at the lower part of the other end of the polishing drum body 1, and the movable end of the lifting member is hingedly connected to the bottom of the supporting power unit; the lifting member is a hydraulic cylinder. The lifting unit described in the utility model includes a movable part and a lifting part, the movable part is used to support the polishing drum body 1, and to support the polishing drum body 1 during and after the lifting process; the above-mentioned hinge can be achieved by connecting with a pin column; the movable end of the same lifting member 7 is also connected to the bottom of the supporting power unit in an articulated manner, and its form can be the same as the former. The lifting member can adjust the angle of the rear end of the polishing drum body 1 from -10 degrees to 10 degrees, and by adjusting the angle of the rear end of the polishing drum body 1, the purpose of controlling the polishing time and direction of the material can be achieved; as shown in the figure, the lifting member 7 is arranged below the ground plane.

[0030] Further, the supporting power unit includes a supporting seat 8 with a bottom and connected to the top of the lifting seat and the movable end of the lifting member, respectively, polishing roller brackets 9 are respectively provided at the top and the two ends of the supporting seat 8, and a driving member and a driven member are provided between the polishing roller brackets 9; the driving member includes a driving motor 10, the shaft of the driving motor 10 is connected to the shaft with a driving gear 12 through a reducer 11, and the driving gear 12 is meshed with a driving gear ring 13 arranged on the outer circumference of the polishing roller body 1; the driven member includes a driven gear 15 arranged on the supporting seat 14, and the driven gear 15 is meshed with a driven gear ring 16 arranged on the outer circumference of the polishing roller body 1. When the utility model is used, the driving motor 10 drives the shaft to rotate through the reducer 11, the driving gear ring 13 is meshed with the driving gear 12, and the shaft drives the driving gear ring 13 to rotate through the driving gear 12, thereby driving the polishing roller body 1 to rotate; the polishing roller body 1 rotates and drives the driven gear ring 16 to rotate, and the driven gear 15 is meshed with the driven gear ring 16, thereby driving the driven gear 15 to rotate.

[0031] Furthermore, automatic retaining ring units are respectively provided between the polishing treatment area and the polishing area, and between the polishing area and the cooling area. The utility model divides the temporal part of the polishing drum body 1 into a polishing treatment area, a polishing area and a cooling area by providing an automatic retaining ring unit. The automatic retaining ring unit can realize the division and connection of the above three areas, thereby achieving the characteristics of energy saving and consumption reduction and improving efficiency; specifically, in combination with the foregoing, it can be known that steam and polishing liquid are introduced into the polishing treatment area, and the closing of the automatic retaining ring unit can reduce heat loss and realize the full mixing of the polishing liquid and urea particles (avoiding the entry of the polishing liquid into the polishing area without sufficient mixing, thereby affecting the polishing efficiency); further, the division and connection of the above three areas can be realized in a variety of structural forms, such as: providing a baffle with a controllable angle, etc.

[0032] Furthermore, the automatic retaining ring unit includes a fixed retaining ring 17 and a movable retaining ring 18, which are cross-arranged, the fixed retaining ring 17 is fixedly connected to the inner wall of the polishing drum body 1, and the movable retaining ring 18 is connected to the adjacent side of the fixed retaining ring 17 through a pull rod type expansion joint 19; a main shaft 20 is provided in the polishing drum body 1, and a shaft seal is provided on the main shaft 20, the shaft seal includes a fixed shaft seal 23 sleeved on the main shaft 20 and a movable shaft seal 25 rotating with the polishing drum body 1, and a power branch line 27 of the pull rod type expansion joint 19 is connected to a power main line 26 arranged on the fixed shaft seal 23 through the movable shaft seal 25. The fixed retaining ring 17 and the movable retaining ring 18 described in the utility model are both retaining rings, and the height of the retaining ring is 0.5m~0.7m; on the one hand, it can avoid the mutual flow of materials in the three areas of polishing treatment area, polishing area and cooling area, so as to achieve the characteristics of ensuring polishing effect and improving work efficiency, and on the other hand, it can reduce heat loss and achieve the purpose of energy saving and consumption reduction; the retaining ring is preferably a fan-shaped structure, the fixed retaining ring 17 is fixedly connected to the inner wall of the polishing drum body 1 (can be welded), the movable retaining ring 18 is connected to the fixed retaining ring 17 through corresponding hinges, the fixed retaining ring 17 and the movable retaining ring 18 are alternately arranged, and the opening and closing of the movable retaining ring 18 are controlled by the pull rod type retractor 19; in the actual production process, the pull rod type retractor 19 can be linked with the lifting angle of the polishing drum body 1, when the angle of the polishing drum body 1 is less than -3 degrees, the pull rod type retractor 19 controls the movable retaining ring 18 to open, so that the material enters the next functional partition.

[0033] Furthermore, there are four fixed retaining rings 17 and four movable retaining rings 18, and four power branch lines 27 are respectively connected to the power main line 26; the rod-type telescopic device 19 is an electric rod-type telescopic device, a hydraulic rod-type telescopic device or a pneumatic rod-type telescopic device; when the rod-type telescopic device 19 is an electric rod-type telescopic device, the power branch line and the power main line are power lines; when the rod-type telescopic device 19 is a hydraulic rod-type telescopic device, the power branch line and the power main line are hydraulic oil lines; when the rod-type telescopic device 19 is a pneumatic rod-type telescopic device, the power branch line and the power main line are gas lines. The rod-type telescopic device 19 described in the utility model can be controlled electrically, pneumatically or hydraulically, and it can be directly purchased on the market, so it is not described in detail.

[0034] Further, the pull rod type expansion joint 19 is arranged at the middle position of one side of the fixed retaining ring 17, and hinges 21 are respectively arranged on the corresponding fixed retaining rings 17 at the upper and lower parts of the pull rod type expansion joint 19. The fixed retaining ring 17 and the movable retaining ring 18 described in the utility model are connected by the hinge 21, and the opening and closing of the movable retaining ring 18 are controlled by the pull rod type expansion joint 19.

[0035] Furthermore, the polishing treatment area, the polishing area and the cooling area are respectively provided with a lifting plate part; the lifting plate part of the polishing treatment area is an L-shaped lifting plate 22, and the lifting plate parts of the polishing area and the cooling area are conical lifting plates 24. The lifting plate parts described in the utility model are distributed inside the polishing treatment area, the polishing area and the cooling area, and are used to achieve uniform mixing and / or polishing of materials. The lifting plate parts can be conventionally arranged; preferably, the polishing treatment area is mainly used to achieve uniform mixing of the polishing liquid and the urea particles, so the lifting plate part inside it is preferably an L-shaped lifting plate 22, and the polishing area and the cooling area are mainly used to achieve polishing of the urea particles, so the lifting plate part inside them is preferably a conical lifting plate 24.

[0036] The working principle of the utility model is as follows: during the production process, first, steam is introduced into the polishing treatment area through the steam polishing liquid input pipeline 2 to increase the temperature, so that the temperature reaches the set temperature, and at the same time, the lifting member 7 is adjusted to make the polishing roller body 1 as a whole 0 degrees (the urea inlet and the urea outlet are at the same height). At this time, the movable retaining ring 18 is closed. When the temperature in the polishing treatment area rises to 60-90°C, ordinary urea produced by one-time granulation is added to the polishing treatment area through the urea inlet. At this time, the urea is concentrated in the polishing treatment area, and then 0-10% polishing liquid is sprayed into the area through the steam polishing liquid input pipeline 2. The spraying time is 5-10s. After the polishing liquid is sprayed for 10 minutes, the polishing roller body 1 is adjusted to -5--10 degrees through the lifting member 7. At this time, the pull rod type retractor 19 between the polishing treatment area and the polishing area is started to open the corresponding movable retaining ring 18, and the polishing roller body During the rotation of the body 1, urea slowly enters the polishing area from the polishing treatment area; after the urea particles completely enter the polishing area, the polishing drum body 1 is adjusted to 0 degrees as a whole through the lifting member 7. At this time, the pull rod type expansion joint 19 between the polishing treatment area and the polishing area is started, so that the corresponding movable retaining ring 18 is closed, so that the urea particles are polished in the polishing area for about 30-60 minutes. After a period of polishing, the lifting member 7 is readjusted to adjust the polishing drum body 1 to -5 to -10 degrees. At this time, the pull rod type expansion joint 19 between the polishing area and the cooling area opens the corresponding movable retaining ring 18. During the rotation of the polishing drum body 1, urea slowly enters the cooling area from the polishing area; then repeat the above operation, so that the material is continuously fed from the urea inlet, and then the angle of the polishing drum body 1 is adjusted by the lifting member 7 to control the material flow to different areas, so as to form continuous production. Preferably, the rod-type expansion joint 19 is pneumatically driven, and the air source is sent to the shaft seal 23 fixed on the main shaft 20 through the air source main pipe. The shaft seal 23 is divided into a fixed shaft seal and a movable shaft seal. The fixed shaft seal is fixed on the main shaft 20, and the movable shaft seal can rotate with the polishing drum body 1. The air source main pipe enters the movable shaft seal through the fixed shaft seal and then disperses to the rod-type expansion joint 19 through the air source branch pipe. The rod-type expansion joint 19 is installed in the middle part of the fixed retaining ring 17. The utility model can not only solve the problem that the urea granulated once is not suitable for coating due to poor roundness, but also realize the characteristics of continuous operation, improved efficiency and reduced energy consumption, which greatly expands the selection range of coated urea core.

[0037] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A polishing device suitable for ordinary urea, the polishing device comprising a polishing drum body (1), characterized in that: The bottom of the polishing drum body (1) is provided with a lifting unit for lifting the polishing drum body (1); the upper part of the lifting unit is provided with a supporting power unit for supporting and rotating the polishing drum body (1); one end of the polishing drum body (1) is provided with a urea inlet, and the other end is provided with a urea outlet; the polishing drum body (1) between the urea inlet and the urea outlet is provided with a polishing treatment area, a polishing area and a cooling area in sequence; A steam polishing liquid input unit is arranged in the polishing treatment area.

2. A polishing device suitable for common urea according to claim 1, characterized in that: The steam polishing liquid input unit comprises a steam polishing liquid input pipeline (2), a nozzle (3) is provided in the steam polishing liquid input pipeline (2) inside the polishing treatment area, and the steam polishing liquid input pipeline (2) outside the polishing treatment area is respectively connected to a steam system (4) and a polishing liquid storage tank (5).

3. A polishing device suitable for common urea according to claim 1, characterized in that: The lifting unit comprises a movable part and a lifting part, wherein the movable part comprises a lifting seat (6) arranged at the lower part of one end of the polishing drum body (1), and the top of the lifting seat is hingedly connected to the bottom of the supporting power unit; The lifting part comprises a lifting member (7) arranged at the lower part of the other end of the polishing drum body (1), and the movable end of the lifting member is hingedly connected to the bottom of the supporting power unit; the lifting member is a hydraulic cylinder.

4. A polishing device suitable for common urea according to claim 3, characterized in that: The supporting power unit comprises a supporting seat (8) having a bottom and connected to the top of the lifting seat and the movable end of the lifting member respectively; polishing roller brackets (9) are respectively provided at both ends of the top of the supporting seat (8); a driving member and a driven member are provided between the polishing roller brackets (9); The driving member comprises a driving motor (10), the shaft of the driving motor (10) is connected to a shaft with a driving gear (12) through a reducer (11), and the driving gear (12) is meshed with a driving gear ring (13) arranged on the outer circumference of the polishing drum body (1); The driven member comprises a driven gear (15) arranged on a support (14), and the driven gear (15) is meshed with a driven gear ring (16) arranged on the outer circumference of the polishing drum body (1).

5. A polishing device suitable for common urea according to claim 1, characterized in that: Automatic retaining ring units are respectively arranged between the polishing treatment area and the polishing area, and between the polishing area and the cooling area.

6. A polishing device suitable for common urea according to claim 5, characterized in that: The automatic retaining ring unit comprises a fixed retaining ring (17) and a movable retaining ring (18). The fixed retaining ring (17) and the movable retaining ring (18) are arranged crosswise, the fixed retaining ring (17) is fixedly connected to the inner wall of the polishing drum body (1), and the movable retaining ring (18) is connected to the adjacent side of the fixed retaining ring (17) through a pull rod type retractor (19); A main shaft (20) is arranged inside the polishing drum body (1), and a shaft seal is sleeved on the main shaft (20). The shaft seal comprises a fixed shaft seal (23) sleeved on the main shaft (20) and a movable shaft seal (25) rotating with the polishing drum body (1). A power branch line (27) of a pull rod type expansion joint (19) is connected to a power main line (26) arranged on the fixed shaft seal (23) through the movable shaft seal (25).

7. A polishing device suitable for common urea according to claim 6, characterized in that: There are four fixed retaining rings (17) and four movable retaining rings (18), and the four power branch lines (27) are respectively connected to the power main line (26); The rod-type telescopic device (19) is an electric rod-type telescopic device, a hydraulic rod-type telescopic device or a pneumatic rod-type telescopic device; When the pull rod type telescopic device (19) is an electric pull rod type telescopic device, the power branch line and the power main line are power lines; When the pull rod type expansion joint (19) is a hydraulic pull rod type expansion joint, the power branch pipeline and the power main pipeline are hydraulic oil pipelines; When the pull-rod type expansion joint (19) is a pneumatic pull-rod type expansion joint, the power branch pipeline and the power main pipeline are gas pipelines.

8. A polishing device suitable for common urea according to claim 7, characterized in that: The pull rod type telescopic device (19) is arranged at a middle position on one side of the fixed retaining ring (17), and hinges (21) are respectively arranged on the corresponding fixed retaining rings (17) at the upper and lower parts of the pull rod type telescopic device (19).

9. A polishing device suitable for common urea according to claim 1, characterized in that: The polishing treatment area, the polishing area and the cooling area are respectively provided with a plate copying part; The copying plate portion of the polishing treatment zone is an L-shaped copying plate (22), and the copying plate portions of the polishing zone and the cooling zone are conical copying plates (24).

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