Sealing device for stirring shaft of polyvinyl chloride polymerizer

Abstract

The utility model relates to a chemical equipment, especially a sealing device of polyvinyl chloride polymerizer stirring shaft. The stirring shaft is sequentially installed with bearing box, upper static ring seat, sealing box and lower static ring seat from top to bottom, and the stirring shaft of the lower part of bearing box is equipped with the shaft sleeve, and the upper and lower static ring seats are equipped with upper and lower static rings respectively, and the shaft sleeve is installed with the upper and lower dynamic rings matched with the upper and lower static rings, the lower end of the shaft sleeve extends out of the lower static ring seat, and the water seal structure is installed between the lower static ring seat and the shaft sleeve, the water seal structure includes the upper cover, the middle cover and the lower cover connected in proper order, the sealing assembly is installed between the upper cover and the middle cover and between the middle cover and the lower cover respectively, the sealing assembly includes the first sealing ring and the second sealing ring, the first sealing ring and the second sealing ring are matched with the shaft sleeve, and the upper cover, the middle cover and the lower cover are connected with the lower static ring seat. The utility model improves the sealing effect greatly, reduces the maintenance cost and improves the production capacity.

Description

Technical Field

[0001] This utility model relates to chemical equipment, and in particular to a sealing device for the stirring shaft of a polyvinyl chloride polymerization reactor. Background Technology

[0002] As one of the most important pieces of equipment in the production plant of polyvinyl chloride (PVC) resin, the polymerization reactor is responsible for the polymerization of vinyl chloride monomer, thereby producing PVC. As is well known, the polymerization of vinyl chloride monomer is an exothermic reaction, releasing a large amount of heat during the process. The higher the temperature, the more vigorous the reaction. If the heat released by the reaction cannot be dissipated in time, the polymerization reactor may explode. Therefore, it is necessary to control the reaction temperature during the polymerization of vinyl chloride monomer to ensure a safe, stable, and controllable process. The method for controlling the reaction temperature in the polymerization reactor is to circulate cold water through the outer jacket and inside the agitator. The continuous circulation of the cold water within the agitator and jacket removes the heat released during the polymerization reaction, thus achieving the goal of controlling the reaction temperature.

[0003] The packing seal of the polymerization reactor is located directly above the mechanical seal. Because the polymerization reactor uses a packing seal, some leakage is unavoidable. There is a skeleton oil seal at the bearing cap, but prolonged wear can cause this seal to deform, reducing its sealing performance. Leaking circulating water flows along the agitator shaft to the bearing end cover on the mechanical seal, then enters the bearing housing, damaging the bearing. During the reaction of polyvinyl chloride in the polymerization reactor, small particles are generated. These particles enter the friction area between the lower dynamic and lower static rings of the mechanical seal, accelerating wear and leading to leakage. Each time the mechanical seal assembly is replaced, the polymerization reactor must be stopped and completely purged, a process that takes approximately two days. The cost of spare parts for each replacement is approximately 23,000 yuan, and each maintenance affects resin production by 54 tons. Chinese utility model patent CN216242294U discloses a multifunctional double-end mechanical seal for reactors, but this design has poor sealing performance. Utility Model Content

[0004] The present invention aims to solve the above-mentioned technical problems, thereby providing a sealing device for the stirring shaft of a polyvinyl chloride polymerization reactor, which greatly improves the sealing effect, reduces maintenance costs, and increases production capacity.

[0005] The technical solution adopted by this utility model to solve its technical problem is as follows: A sealing device for the stirring shaft of a polyvinyl chloride polymerization reactor is disclosed. The stirring shaft is provided with a bearing housing, an upper stationary ring seat, a sealing housing, and a lower stationary ring seat in sequence from top to bottom. A bushing is provided at the lower part of the stirring shaft of the bearing housing. The upper and lower stationary ring seats are respectively provided with upper and lower stationary rings. The bushing is provided with upper and lower moving rings that cooperate with the upper and lower stationary rings. The lower end of the bushing extends into the lower stationary ring seat. A water seal structure is installed between the lower stationary ring seat and the bushing. The water seal structure includes an upper cover, a middle cover, and a lower cover connected in sequence. Sealing components are installed between the upper cover and the middle cover, and between the middle cover and the lower cover, respectively. The sealing components include a first sealing ring and a second sealing ring. Both the first sealing ring and the second sealing ring cooperate with the bushing. The upper cover, the middle cover, and the lower cover are connected to the lower stationary ring seat.

[0006] Compared with the prior art, the present invention, which adopts the above technical solution, has the following beneficial effects: 1) It ensures that small particles produced during the reaction inside the polymerization reactor will not enter the friction surface between the lower moving ring and the lower stationary ring, making it safer and more reliable, greatly improving the sealing effect, and preventing the cooling water flowing down from the stirring packing from entering the mechanical seal bearing housing; 2) Improved bearing life by 3 years and mechanical seal life by 1.5 years, reduced maintenance costs, saved 0.8 million yuan in spare parts costs per reactor per year, and increased production capacity.

[0007] Furthermore, the optimized solution of this utility model is: The first sealing ring and the second sealing ring have a multi-lobed structure, and tension springs are respectively arranged around the outer circumferential surfaces of the first sealing ring and the second sealing ring.

[0008] The first sealing ring is a three-lobed ring, and the second sealing ring is a six-lobed ring.

[0009] Both the middle cover and the lower cover have U-shaped cross-sections.

[0010] The bottom of the second sealing ring is provided with a push ring, and springs are evenly distributed at the bottom of the push ring. The springs are installed in the spring holes of the middle cover and the lower cover.

[0011] The bottom of the grooves of the middle cover and the lower cover are fitted with straight pins, and the other end of the straight pins passes through the push ring and is placed in the round hole of the first sealing ring and the second sealing ring.

[0012] Sealing gaskets are installed between the upper cover and the middle cover, and between the middle cover and the lower cover.

[0013] The bearing housing is equipped with a first oil seal and a second oil seal on its upper end cover. Both the first oil seal and the second oil seal are fitted with the stirring shaft.

[0014] The top of the upper end cover of the bearing housing is provided with a water-slinging ring, which is connected to the stirring shaft. Attached Figure Description

[0015] Figure 1This is a schematic diagram of the overall structure of an embodiment of the present utility model; Figure 2 This is a schematic diagram of the water seal structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the bushing according to an embodiment of the present utility model; Figure 4 This is a schematic diagram of the upper cover of an embodiment of the present utility model; Figure 5 This is a schematic diagram of the lower stationary ring seat according to an embodiment of the present utility model; Figure 6 This is a schematic diagram of the water-throwing ring seat according to an embodiment of the present utility model.

[0016] In the diagram: 1. Stirring shaft; 2. Bearing housing; 201. Bearing housing body; 202. Round nut; 203. Upper end cover; 204. Lower end cover; 205. First oil seal; 206. Second oil seal; 207. Shaft sleeve; 3. Set screw; 301. Upper stationary ring seat; 4. Upper stationary ring; 5. Upper moving ring; 6. Sealing housing; 7. Lower stationary ring seat; 8. Lower stationary ring; 9. Lower moving ring; 10. Upper cover; 11. Middle cover; 12. Lower cover; 13. First sealing ring; 14. Second sealing ring; 15. Tension spring; 16. Push ring; 17. Spring; 18. Straight pin; 19. Water-slinging ring; 20. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0018] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0019] See Figures 1-6This embodiment provides a sealing device for the stirring shaft of a polyvinyl chloride polymerization reactor, mainly composed of a bearing housing 2, a shaft sleeve 3, an upper stationary ring seat 4, an upper stationary ring 5, an upper moving ring 6, a sealing box 7, a lower stationary ring seat 8, a lower stationary ring 9, a lower moving ring 10, and a water seal structure. The bearing housing 2 is installed on the stirring shaft 1. The bearing housing 2 is composed of a bearing housing body 201, a bearing 202, a round nut 203, an upper end cover 204, and a lower end cover 205. The stirring shaft 1 inside the bearing housing 2 is fitted with the bearing 202. A round nut 203 is installed at the top of the stirring shaft 1 of the bearing 202, and the round nut 203 is used for positioning the bearing 202. An upper end cover 204 and a lower end cover 205 are respectively installed at the upper and lower ends of the bearing housing body 201. A first oil seal 206 and a second oil seal 207 are installed between the upper end cover 204 and the stirring shaft 1. The first oil seal 206 and the second oil seal 207 are skeleton oil seals, and the two oil seals improve the sealing effect.

[0020] A bushing 3 is installed on the stirring shaft 1 below the lower end cover 205. The bushing 3 is connected to the stirring shaft 1 by a set screw 301 and rotates with the stirring shaft 1. An upper stationary ring seat 4, a sealing housing 7, and a lower stationary ring seat 8 are fitted on the outer side of the bushing 3. The upper stationary ring seat 4 is bolted to the sealing housing 7, and the sealing housing 7 and the stationary ring seat 8 are bolted together. The upper end cover 204, the bearing housing 201, the lower end cover 205, the upper stationary ring seat 4, and the sealing housing 7 are bolted together. An upper stationary ring 5 is installed inside the upper stationary ring seat 4, and a lower stationary ring 9 is installed inside the lower stationary ring seat 8. An upper moving ring 6 and a lower moving ring 10 are installed on the bushing 3. The upper moving ring 6 and the lower moving ring 10 rotate with the stirring shaft. The upper moving ring 6 is in a sealing fit with the upper stationary ring 5, and the lower moving ring 10 is in a sealing fit with the lower stationary ring 9.

[0021] The lower end of the bushing 3 extends into a lower stationary ring seat 8. A water seal structure is installed between the lower stationary ring seat 8 and the bushing 3. The water seal structure mainly consists of an upper cover 11, a middle cover 12, a lower cover 13, a first sealing ring 14, a second sealing ring 15, a tension spring 16, a push ring 17, a spring 18, and a straight pin 19. The upper cover 11, the middle cover 12, and the lower cover 13 are connected by bolts. Sealing gaskets are installed between the upper cover 11 and the middle cover 12, and between the middle cover 12 and the lower cover 13, respectively. The upper cover 11, the middle cover 12, the lower cover 13, and the lower stationary ring seat 8 are connected by bolts. Both the middle cover 12 and the lower cover 13 have U-shaped cross-sections. Sealing assemblies are installed between the upper cover 11 and the middle cover 12, and between the middle cover 12 and the lower cover 13. The sealing assemblies include a first sealing ring 14 and a second sealing ring 15. Both the first sealing ring 14 and the second sealing ring 15 mate with the bushing 3. The first sealing ring 14 is a three-lobed ring, and the second sealing ring 15 is a six-lobed ring. Tension springs 16 are respectively arranged around the outer circumference of the first sealing ring 14 and the second sealing ring 15. A push ring 17 is provided at the bottom of the second sealing ring 15. Springs 18 are evenly distributed at the bottom of the push ring 17. The springs 18 are installed in the spring holes of the middle cover 12 and the lower cover 13. The springs 18 and the push ring 17 ensure that the first sealing ring 14 and the second sealing ring 15 are tightly fitted together. A straight pin 19 is installed at the bottom of the grooves of the middle cover 12 and the lower cover 13. The upper end of the straight pin 19 passes through the push ring 17 and is placed in the circular hole of the first sealing ring 14 and the second sealing ring 15. The straight pin 19 is used for positioning and limiting the first sealing ring 14 and the second sealing ring 15. The water seal structure ensures that small particles produced in the polymerization reactor will not enter the friction surface between the lower moving ring 10 and the lower stationary ring 9, making it safer and more reliable.

[0022] As an embodiment of this utility model, a water-slinging ring 20 is provided on the top of the upper end cover 204 of the bearing housing 2. The water-slinging ring 20 is connected to the stirring shaft 1 by radial bolts. An O-ring is installed inside the water-slinging ring 20. The water-slinging ring 20 and the upper pressure cover 204 form a water seal assembly to ensure that the cooling water flowing down from the stirring packing cannot enter the bearing housing 2.

[0023] After this utility model was put into use, it has shown good results. Compared with the original bearing, the service life has increased by 3 years, the overall service life has increased by 1.5 years, the spare parts cost per reactor has been reduced by 0.8 million yuan per year, and the resin production has increased by 18 tons. With 12 reactors in the workshop, the total spare parts cost saved is 0.8 × 12 = 9.6 million yuan per year, and the resin production has increased by 18 × 12 = 216 tons per year.

[0024] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A sealing device for the stirring shaft of a polyvinyl chloride polymerization reactor, wherein the stirring shaft is provided with a bearing housing, an upper stationary ring seat, a sealing housing, and a lower stationary ring seat in sequence from top to bottom; a bushing is provided on the stirring shaft at the lower part of the bearing housing; upper and lower stationary ring seats are respectively provided with upper and lower stationary rings; and upper and lower moving rings that cooperate with the upper and lower stationary rings are installed on the bushing, characterized in that: The lower end of the bushing extends into a lower stationary ring seat. A water seal structure is installed between the lower stationary ring seat and the bushing. The water seal structure includes an upper cover, a middle cover, and a lower cover connected in sequence. Sealing components are installed between the upper cover and the middle cover, and between the middle cover and the lower cover, respectively. The sealing components include a first sealing ring and a second sealing ring. Both the first sealing ring and the second sealing ring cooperate with the bushing. The upper cover, the middle cover, and the lower cover are connected to the lower stationary ring seat.

2. The sealing device for the stirring shaft of the polyvinyl chloride polymerization reactor according to claim 1, characterized in that: The first sealing ring and the second sealing ring have a multi-lobed structure, and tension springs are respectively arranged around the outer circumferential surfaces of the first sealing ring and the second sealing ring.

3. The sealing device for the stirring shaft of the polyvinyl chloride polymerization reactor according to claim 2, characterized in that: The first sealing ring is a three-lobed ring, and the second sealing ring is a six-lobed ring.

4. The sealing device for the stirring shaft of the polyvinyl chloride polymerization reactor according to claim 1, characterized in that: Both the middle cover and the lower cover have U-shaped cross-sections.

5. The sealing device for the stirring shaft of the polyvinyl chloride polymerization reactor according to claim 1, characterized in that: The bottom of the second sealing ring is provided with a push ring, and springs are evenly distributed at the bottom of the push ring. The springs are installed in the spring holes of the middle cover and the lower cover.

6. The sealing device for the stirring shaft of the polyvinyl chloride polymerization reactor according to claim 1, characterized in that: The bottom of the grooves of the middle cover and the lower cover are fitted with straight pins, and the other end of the straight pins passes through the push ring and is placed in the round hole of the first sealing ring and the second sealing ring.

7. The sealing device for the stirring shaft of the polyvinyl chloride polymerization reactor according to claim 1, characterized in that: Sealing gaskets are installed between the upper cover and the middle cover, and between the middle cover and the lower cover.

8. The sealing device for the stirring shaft of the polyvinyl chloride polymerization reactor according to claim 1, characterized in that: The upper end cover of the bearing housing is equipped with a first oil seal and a second oil seal, both of which are fitted to the stirring shaft.

9. The sealing device for the stirring shaft of the polyvinyl chloride polymerization reactor according to claim 1, characterized in that: The top of the bearing housing cover is equipped with a water-slinging ring, which is connected to the stirring shaft.

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