A stirring tank shaft end sealing device with tee joint backflow indicating assembly

Abstract

The application discloses a stirring tank shaft end sealing device with a three-way backflow indicating assembly and relates to the technical field of industrial sealing.The stirring tank shaft end sealing device comprises a shaft sleeve and a lower pressing cover, the inside of the shaft sleeve is tightly installed with a stirring main shaft, the outer surface of the shaft sleeve is provided with a tank top flange, and the outer surface of the shaft sleeve is tightly fitted and installed with a centrifugal liquid throwing disc.The stirring tank shaft end sealing device adopts a pure mechanical structure design, does not need an external power supply and an electrical sensor, integrates two functions of medium backflow and state early warning by using a three-way pipe fitting, can guide the leakage medium to the tank body in a directional way through a backflow pipe, can intuitively reflect the sealing operation state through a transparent indicating pipe by relying on the principle of a communicating vessel, realizes visual self-diagnosis of sealing failure, and thus work personnel can carry out preventive maintenance in advance according to the liquid level change, the maintenance operation is convenient, the equipment downtime length and operation and maintenance cost are effectively reduced, and the stirring tank shaft end sealing device is especially suitable for use in a use scene with strict electrical safety requirements.

Description

Technical Field

[0001] This invention relates to the field of industrial sealing technology, specifically to a shaft end sealing device for a mixing tank with a three-way reflux indicator assembly. Background Technology

[0002] In emulsion explosive production lines, mixing equipment such as aqueous dissolution tanks typically operate at high temperatures, with a vertical stirring shaft extending vertically into the top of the tank. These devices often employ traditional skeleton oil seals or single-stage packing seals.

[0003] However, under harsh actual operating conditions, viscous or particulate media accelerate the wear of the sealing lip, leading to increased clearance. Traditional sealing structures lack radial automatic compensation capabilities, causing leakage to rise sharply with wear. Furthermore, the lack of purely mechanical early warning mechanisms means operators cannot visually assess the wear and failure status of the seals without disassembling the equipment or relying on electrical instruments, often only discovering the problem passively when leakage has become severe enough to pollute the environment. Simultaneously, the vapor generated by the high-temperature medium inside the tank condenses in the cooler area of ​​the shaft end. When mixed with the leaking liquid phase, it easily crystallizes in narrow channels, clogging the pipeline and accelerating seal failure. Moreover, replacing traditional sealing devices often requires disassembling shaft components such as the motor and reducer, and may even require emptying the tank and removing the main shaft, making maintenance difficult and time-consuming. Summary of the Invention

[0004] The purpose of this invention is to provide a sealing device for the shaft end of a mixing tank with a three-way reflux indicator assembly, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a shaft end sealing device for a mixing tank with a three-way reflux indicator assembly, comprising a bushing and a lower pressure cap. A mixing main shaft is tightly installed inside the bushing, and a tank top flange is provided on the outer surface of the bushing. A centrifugal slinger is fitted onto the outer surface of the bushing via a tight fit, and an elastic self-compensating spiral sealing ring is provided above the centrifugal slinger. Positioning bosses are symmetrically installed on both sides of the elastic self-compensating spiral sealing ring. The lower pressure cap is bolted to the tank top flange. Externally, the upper half of the elastic self-compensating spiral sealing ring is embedded in the inner hole of the lower pressure cover, the positioning boss is inserted into the positioning groove at the corresponding position of the inner hole of the lower pressure cover, and the lower half of the positioning boss is embedded in the inner hole of the top flange of the tank body. The inner wall of the lower pressure cover is provided with a liquid collection chamber, and a condensation guide ring is installed above the liquid collection chamber. A three-way pipe is provided on one side of the bottom of the liquid collection chamber, and a transparent indicator pipe is installed on the top of the three-way pipe. A return pipe is provided at the bottom of the three-way pipe, and a liquid outlet pipe is installed on the side of the three-way pipe near the stirring shaft.

[0006] Furthermore, a miniature baffle is installed inside the tee fitting near the input end of the transparent indicator tube, and a vent hole is provided at the end of the transparent indicator tube.

[0007] Furthermore, the inner hole of the condensation guide ring is provided with an annular sealing groove, and an auxiliary sealing ring is installed inside the annular sealing groove.

[0008] Furthermore, the elastic self-compensating spiral sealing ring is made entirely of modified polytetrafluoroethylene, and the inner hole of the elastic self-compensating spiral sealing ring is provided with a reverse spiral return groove, and the inner hole and the outer circle of the bushing are elastically and dynamically clamped together.

[0009] Furthermore, the centrifugal sling plate is a truncated conical rotating body structure, and the centrifugal sling plate is made of fluororubber material, and the surface of the centrifugal sling plate is inclined downward from the near-axis end to the far-axis end.

[0010] Furthermore, the connecting pipes between the tee fitting, return pipe, transparent indicator pipe, and outlet pipe are all made of corrosion-resistant elastic material, and the pipes and the interfaces of the tee fitting are connected by interference fit.

[0011] Furthermore, the lower end face of the condensation guide ring is an annular inclined surface, with the near-axial end of the annular inclined surface higher than the far-axial end, and the surface of the inclined surface is polished, with the lowest edge of the condensation guide ring facing directly above the liquid collection chamber.

[0012] Furthermore, a dustproof ring is fitted onto the bushing and rotates synchronously with it, and the transparent indicator tube is vertically arranged on the outside of the lower pressure cover, with a preset warning line marked on the outer wall of the transparent indicator tube for judging seal failure.

[0013] This invention provides a shaft end sealing device for a mixing tank with a three-way reflux indicator assembly, which has the following advantages: 1. This invention adopts a multi-stage mechanical seal structure, with a centrifugal slinger and an elastic self-compensating spiral sealing ring forming a double sealing defense. The sealing ring uses a reverse spiral groove to generate a pumping effect to prevent leakage in the reverse direction. Combined with modified polytetrafluoroethylene material, it achieves elastic self-compensation after wear, effectively solving the problems of easy wear, increased gaps, and aggravated leakage in traditional seals. At the same time, the condensate guiding ring can guide and collect the high-temperature steam condensate in the tank in a directional manner. With the help of the auxiliary sealing ring, it can prevent steam from overflowing and avoid condensate crystallization and blockage of pipelines. Then, the leakage liquid and condensate are guided back to the tank through the three-way pipe fitting return pipe, realizing closed-loop recovery of the medium.

[0014] 2. This invention adopts a purely mechanical structure design, requiring no external power supply or electrical sensors. It integrates two major functions: media reflux and status early warning, using a three-way fitting. Leaking media can be guided back to the tank through the reflux pipe. At the same time, relying on the principle of communicating vessels, the sealing operation status is intuitively reflected through a transparent indicator tube, realizing visual self-diagnosis of sealing faults. Staff can carry out preventive maintenance in advance based on changes in liquid level. Maintenance operations are convenient, effectively reducing equipment downtime and maintenance costs, and are especially suitable for application scenarios with stringent electrical safety requirements. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of a mixing tank shaft end sealing device with a three-way reflux indicator assembly according to the present invention. Figure 2 This is a partial cross-sectional view of a mixing tank shaft end sealing device with a three-way reflux indicator assembly according to the present invention. Figure 3 This is a schematic diagram of the unfolded structure of the elastic self-compensating spiral sealing ring and the condensation guide ring of the mixing tank shaft end sealing device with a three-way reflux indicator assembly according to the present invention. Figure 4 This is a schematic cross-sectional view of the connection structure of the tee fitting of the mixing tank shaft end sealing device with tee reflux indicator assembly according to the present invention; Figure 5 This is a cross-sectional view of the elastic self-compensating spiral sealing ring and condensation guide ring of the mixing tank shaft end sealing device with a three-way reflux indicator assembly according to the present invention.

[0016] In the diagram: 1. Bushing; 2. Centrifugal slinger; 3. Elastic self-compensating spiral sealing ring; 4. Lower pressure cap; 5. T-fitting pipe; 6. Return pipe; 7. Transparent indicator tube; 8. Condensation guide ring; 9. Upper pressure cap; 10. Dustproof sealing ring; 11. Dustproof ring; 12. Miniature baffle; 13. Vent hole; 14. Agitator shaft; 15. Top flange of tank; 16. Discharge pipe; 17. Collection chamber; 18. Auxiliary sealing ring; 19. Positioning boss. Detailed Implementation

[0017] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0018] like Figures 1-5As shown, a shaft end sealing device for a stirred tank with a three-way reflux indicator assembly includes a shaft sleeve 1, a centrifugal sling plate 2, an elastic self-compensating spiral sealing ring 3, a lower pressure cap 4, a three-way fitting 5, a reflux pipe 6, a transparent indicator pipe 7, a condensate guide ring 8, an upper pressure cap 9, a dustproof sealing ring 10, a dustproof ring 11, a miniature baffle 12, a vent hole 13, a stirring shaft 14, a tank top flange 15, a liquid outlet pipe 16, a liquid collection chamber 17, an auxiliary sealing ring 18, and a positioning boss 19. The stirring shaft 14 is tightly installed inside the shaft sleeve 1, and the tank top flange 15 is provided on the outer surface of the shaft sleeve 1. The centrifugal sling plate 2 is tightly fitted onto the outer surface of the shaft sleeve 1, and the elastic self-compensating spiral sealing ring 3 is provided above the centrifugal sling plate 2. The centrifugal sling plate 2 is truncated conical in shape. The centrifugal sling plate 2 is made of fluororubber and its surface slopes downward from the near-axis end to the far-axis end. The elastic self-compensating spiral sealing ring 3 is made of modified polytetrafluoroethylene and has a reverse spiral return groove in its inner hole. The inner hole is elastically and dynamically clamped to the outer circle of the bushing 1. Positioning bosses 19 are symmetrically installed on both sides of the elastic self-compensating spiral sealing ring 3. The lower pressure cover 4 is fixed to the outside of the top flange 15 of the tank by bolts. During the operation of the stirring main shaft 14, the bushing 1, which is clamped and fixed on the stirring main shaft 14, rotates synchronously with the main shaft. The truncated cone-shaped centrifugal sling plate 2, which is fitted on the outside of the bushing 1 and the inside of the top flange 15 of the tank, rotates synchronously, forming the first primary sealing defense line of the device.The centrifugal sling plate 2 is made of fluororubber and has an overall truncated conical structure. The plate surface is inclined downward from the near-axis end to the far-axis end. During rotation, it can rely on centrifugal force to efficiently throw the splashed medium and the liquid film climbing along the axial surface of the stirring main shaft 14 back into the tank, greatly reducing the leakage of medium from the source. The outer edge of the centrifugal sling plate 2 can generate flexible deformation when rotating, forming a flexible fit with the opening of the top flange 15 of the tank to assist in sealing. A dedicated gap is reserved between the centrifugal sling plate 2 and the top flange 15 of the tank to completely avoid medium retention and accumulation, eliminate the risk of local liquid seepage, and effectively block most of the medium leakage paths. After the first primary protection, a very small amount of the medium that seeps in will enter the area of ​​the upper elastic self-compensating spiral sealing ring 3. This component is the second sealing line of the core active sealing structure of the device. The upper half of the elastic self-compensating spiral sealing ring 3 is embedded in the inner hole of the lower pressure cover 4, and the positioning boss 19 is engaged in the lower pressure cover 4. The positioning grooves corresponding to the holes, and the lower half of the positioning boss 19 is embedded in the inner hole of the top flange 15 of the tank body, the elastic self-compensating spiral sealing ring 3 is made of modified polytetrafluoroethylene and has an integral ring structure. Its outer circle is provided with symmetrical positioning bosses 19. The positioning bosses 19 are inserted into the positioning grooves in the inner hole of the lower pressure cover 4 to achieve circumferential positioning, ensuring that the elastic self-compensating spiral sealing ring 3 is stationary throughout the process and does not rotate with the bushing 1. The upper half of the elastic self-compensating spiral sealing ring 3 is embedded in the inner hole of the lower pressure cover 4, and the lower half is embedded in the inner hole of the top flange 15 of the tank body. It is clamped and fixed by the fasteners of the lower pressure cover 4 and the top flange 15 of the tank body to achieve axial stable assembly. The inner hole of the elastic self-compensating spiral sealing ring 3 is machined with a reverse spiral return groove. When the bushing 1 rotates, it can drive the medium in the gap to flow. Relying on the spiral groove to form a reverse pumping effect, it actively pumps the small amount of outwardly leaked medium back into the tank body to achieve dynamic active sealing. Meanwhile, relying on the high elasticity of modified polytetrafluoroethylene, when the elastic self-compensating spiral sealing ring 3 experiences long-term friction and wear, and the clearance between it and the bushing 1 increases, it can continuously tighten the outer circle of the bushing 1 through its own radial elastic contraction, automatically compensating for the wear clearance, maintaining the sealing fit accuracy at all times, significantly extending the service life of the sealing components, and reducing the cost of frequent replacements. To address the issues of high-temperature steam leakage and condensate turbulence inside the tank, a liquid collection chamber 17 is provided on the inner wall of the lower pressure cover 4, and a condensation guide ring 8 is installed above the liquid collection chamber 17. The lower end face of the condensation guide ring 8 is an annular inclined surface, with the near-axial end of the annular inclined surface higher than... The far-axis end of the condensation guide ring 8 has a polished surface, and the lowest edge of the condensation guide ring 8 is directly above the liquid collection chamber 17. The inner hole of the condensation guide ring 8 is provided with an annular sealing groove, and an auxiliary sealing ring 18 is installed inside the annular sealing groove. The lower end of the condensation guide ring 8 is a high-precision polished annular bevel. The structure is inclined with the near-axis end high and the far-axis end low. The high-temperature steam rising from the tank quickly condenses into a liquid medium after contacting the bevel. The condensate can slide smoothly down the bevel under gravity and accurately flow into the annular liquid collection chamber 17 inside the inner wall of the lower pressure cover 4, so as to achieve unified collection and centralized treatment of condensate.Meanwhile, an annular sealing groove is opened in the inner hole of the condensation guide ring 8, and an auxiliary sealing ring 18 is installed in the groove. The auxiliary sealing ring 18 is tightly fitted and sealed with the outer circle of the bushing 1, thus doubly blocking the high-temperature steam in the tank from escaping outward from the assembly gap between the bushing 1 and the condensation guide ring 8. At the same time, it effectively avoids turbulent flow of condensate and local accumulation, and eliminates abnormal problems such as pipeline crystallization blockage and misjudgment of liquid level caused by media residue. The lowest point of the annular liquid collection chamber 17 on the inner wall of the lower pressure cover 4 is connected to the three-way return indicator component. A three-way pipe fitting 5 is provided on one side of the bottom of the liquid collection chamber 17, and a transparent indicator tube 7 is installed on the top of the three-way pipe fitting 5. A return pipe 6 is provided at the bottom of the three-way pipe fitting 5, and a liquid outlet pipe 16 is installed on the side of the three-way pipe fitting 5 near the stirring main shaft 14.

[0019] like Figure 1 and Figure 4As shown, a miniature baffle 12 is installed inside the tee fitting 5 near the input end of the transparent indicator tube 7, and a vent hole 13 is provided at the end of the transparent indicator tube 7. The connecting pipes between the tee fitting 5, the return pipe 6, the transparent indicator tube 7, and the outlet pipe 16 are all made of corrosion-resistant elastic material, and the pipes and the interfaces of the tee fitting 5 are connected by interference fit. A dustproof ring 11 that rotates synchronously with the bushing 1 is fitted on it. The transparent indicator tube 7 is vertically arranged outside the lower pressure cover 4, and the outer wall of the transparent indicator tube 7 is marked with a preset warning line for judging the seal failure. The tee return indicator assembly consists of the tee fitting 5 and the matching corrosion-resistant elastic pipes, including the outlet pipe 16, the return pipe 6, and the transparent indicator tube 7, which can realize the automatic return of leakage liquid and condensate and the visual early warning of the sealing status. The trace amounts of leaked liquid and steam condensate collected in the collection chamber 17 can flow smoothly into the tee fitting 5 through the bottom outlet pipe 16. Under normal sealing conditions, the overall leakage is minimal. The medium flowing into the tee fitting 5 can rely entirely on gravity to flow directly back into the tank through the return pipe 6 connecting to the tank body. The outlet of the return pipe 6 is arranged vertically downwards and precisely positioned above the highest safe liquid level in the tank, with a reserved dedicated air gap to completely avoid liquid accumulation and backflow problems at the return port, ensuring continuous and smooth return of the medium. At this time, there is no liquid accumulation in the vertically installed transparent indicator tube 7 on the outside of the lower pressure cap 4. At the same time, a miniature baffle 12 is installed at the third interface inlet inside the tee fitting 5, which can effectively block liquid splashing and turbulence interference during the return process, structurally avoiding false liquid level indication and ensuring warning accuracy. A vent hole 13 is opened at the top of the transparent indicator tube 7 to keep the inside of the tube connected to the atmosphere. Utilizing the principle of communicating vessels, this ensures accurate liquid level display. A dedicated warning line is marked on the outer wall of the tube, providing a direct basis for inspection and judgment. In the event of seal failure, when the elastic self-compensating spiral sealing ring 3 wears more rapidly, the sealing gap increases sharply, and the leakage of the medium significantly exceeds the rated drainage capacity of the return pipe 6, medium will accumulate inside the tee fitting 5, the liquid level will continue to rise, and the excess liquid will flow into the transparent indicator tube 7, forming a visible liquid column. Inspectors can determine the sealing status by observing the liquid column height. When the liquid column rises to the warning line position on the pipe wall, the failure of the core seal can be accurately determined, allowing for advance planning of shutdown maintenance and replacement of the elastic self-compensating spiral sealing ring 3. This prevents the seal failure from continuing to worsen, leading to medium leakage, equipment failure, and production safety hazards, achieving early warning of faults and preventative maintenance.

[0020] In summary, this mixing tank shaft end sealing device with a three-way reflux indicator assembly is first based on... Figures 1-5 The structure shown, in use, includes a shaft end seal for the vertical stirring spindle 14 of the emulsion explosive aqueous phase dissolution tank. This device is integrally mounted above the top flange 15 of the tank body. Figure 2In the middle section, the lower part is the equipment side, and the upper part is the atmospheric side. During the operation of the stirring main shaft 14, the bushing 1, which is tightly fixed to the stirring main shaft 14, rotates synchronously with the main shaft. The truncated cone-shaped centrifugal sling plate 2, which is fitted on the outside of the bushing 1 and the inside of the top flange 15 of the tank, rotates synchronously, forming the first primary sealing line of the device. The centrifugal sling plate 2 is made of fluororubber and has an overall truncated cone structure. The plate surface is inclined downward from the near-axis end to the far-axis end. During rotation, it can rely on centrifugal force to efficiently throw the splashed medium in the tank and the liquid film climbing along the axial surface of the stirring main shaft 14 back into the tank, greatly reducing the leakage of medium from the source. Meanwhile, the outer edge of the centrifugal slinger 2 can generate flexible deformation when it rotates, forming a flexible fit auxiliary seal with the opening of the top flange 15 of the tank. In addition, a dedicated gap is reserved between the centrifugal slinger 2 and the top flange 15 of the tank to completely avoid the retention and accumulation of media, eliminate the hidden danger of local liquid seepage, and effectively block most of the media seepage paths. After the first primary protection, the extremely small amount of seeping media will enter the area of ​​the elastic self-compensating spiral sealing ring 3 above. This component is the second sealing defense line of the core active sealing structure of the device. The elastic self-compensating spiral sealing ring 3 is made of modified polytetrafluoroethylene and has an integral ring structure. Its outer circle is provided with symmetrical positioning bosses 19. The positioning bosses 19 are engaged with the positioning grooves in the inner hole of the lower pressure cover 4 to achieve circumferential positioning and ensure that the elastic self-compensating spiral sealing ring 3 remains stationary throughout the process and does not rotate with the bushing 1. The upper half of the elastic self-compensating spiral sealing ring 3 is embedded in the inner hole of the lower pressure cover 4, and the lower half is embedded in the inner hole of the top flange 15 of the tank body. It is clamped and fixed by the fasteners of the lower pressure cover 4 and the top flange 15 of the tank body to achieve axially stable assembly. The inner hole of the elastic self-compensating spiral sealing ring 3 is machined with a reverse spiral return groove. When the bushing 1 rotates, it can drive the medium in the gap to flow. Relying on the spiral groove, a reverse pumping effect is formed to actively pump the small amount of outwardly leaked medium back into the tank body to achieve dynamic active sealing. Meanwhile, relying on the high elasticity of modified polytetrafluoroethylene, when the elastic self-compensating spiral sealing ring 3 experiences long-term friction and wear, and the clearance between it and the bushing 1 increases, it can continuously tighten the outer circle of the bushing 1 through its own radial elastic contraction, automatically compensating for the wear clearance, maintaining the sealing fit accuracy at all times, significantly extending the service life of the sealing components, and reducing the cost of frequent replacements. To address the issues of high-temperature steam leakage and condensate turbulence inside the tank, the device is equipped with a condensation guide ring 8 above the liquid collection chamber 17 to achieve specific protection and media recovery. The lower end of the condensation guide ring 8 is a high-precision polished annular inclined surface, with a structure that is higher near the axis and lower far from the axis. High-temperature steam escaping upwards from the tank quickly condenses into a liquid medium after contacting the inclined surface. The condensate can then slide smoothly down the inclined surface under gravity, precisely flowing into the annular liquid collection chamber 17 inside the lower pressure cover 4, achieving unified collection and centralized treatment of the condensate.Meanwhile, an annular sealing groove is opened in the inner hole of the condensation guide ring 8, and an auxiliary sealing ring 18 is installed in the groove. The auxiliary sealing ring 18 is tightly fitted and sealed with the outer circle of the bushing 1, thus doubly blocking the high-temperature steam in the tank from escaping outward from the assembly gap between the bushing 1 and the condensation guide ring 8. At the same time, it effectively avoids turbulent flow of condensate and local sludge accumulation, and eliminates abnormal problems such as pipeline crystallization blockage and misjudgment of liquid level caused by residual media. The lowest point of the annular liquid collection cavity 17 on the inner wall of the lower pressure cover 4 is connected to the three-way return indicator component. This component consists of a three-way fitting 5 and matching corrosion-resistant elastic pipeline, including an outlet pipe 16, a return pipe 6 and a transparent indicator pipe 7, which can realize automatic return of leakage liquid and condensate and visual early warning of sealing status. The trace amounts of leaked liquid and condensed vapor collected in the collection chamber 17 can flow smoothly into the tee fitting 5 through the bottom outlet pipe 16. Under normal sealing conditions, the overall leakage is minimal. The medium flowing into the tee fitting 5 can rely entirely on gravity to flow directly back into the tank through the return pipe 6 connecting to the tank body. The outlet of the return pipe 6 is vertically downward and precisely positioned above the highest safe liquid level in the tank, with a reserved air gap to completely avoid liquid accumulation and backflow problems at the return port, ensuring continuous and smooth return of the medium. At this time, there is no liquid accumulation in the vertically installed transparent indicator tube 7 on the outside of the lower pressure cover 4. At the same time, a miniature baffle 12 is set at the inlet of the third interface inside the tee fitting 5, which can effectively block liquid splashing and turbulence interference during the return process, structurally avoiding false liquid level display and ensuring warning accuracy. A vent hole 13 is opened at the top of the transparent indicator tube 7 to keep the inside of the tube connected to the atmosphere. Relying on the principle of communicating vessels, it ensures accurate liquid level display. A special warning line is marked on the outer wall of the tube to provide a direct basis for inspection and judgment. Under sealing failure conditions, when the wear of the elastic self-compensating spiral sealing ring 3 intensifies and the sealing gap increases sharply, and the leakage of the medium significantly exceeds the rated drainage capacity of the return pipe 6, medium will accumulate inside the tee fitting 5, the liquid level will continue to rise, and the excess liquid will flow into the transparent indicator tube 7, forming a visible liquid column. Inspection personnel can determine the sealing status by observing the height of the liquid column. When the liquid column rises to the warning line on the pipe wall, the failure of the core sealing component can be accurately determined, and shutdown maintenance and replacement of the elastic self-compensating spiral sealing ring 3 can be planned in advance to avoid the continuous deterioration of sealing failure leading to medium leakage, equipment failure, and production safety hazards. This achieves early warning of failure and preventive maintenance. The uppermost part of the device is equipped with a dustproof protection structure, which consists of an upper pressure cover 9, a stationary dustproof sealing ring 10, and a dustproof ring 11 that rotates with the shaft. A stationary dustproof sealing ring 10 is fixedly installed on the inner wall of the upper pressure cover 9, and a dustproof ring 11 that can rotate synchronously with the shaft is fitted on the outer side of the bushing 1. The two work together dynamically to form a closed-loop dustproof barrier on the outermost side of the device, effectively preventing external dust, equipment cleaning fluid, and environmental impurities from entering the device. This provides all-round protection for precision core components such as the sealing structure and the three-way backflow warning component, preventing impurities from getting stuck, worn, or blocked, and ensuring the long-term stable operation of the device.

[0021] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A shaft end sealing device for a mixing tank with a three-way reflux indicator assembly, comprising a shaft sleeve (1) and a lower pressure cap (4), characterized in that, The bushing (1) is fitted with a stirring shaft (14), and the outer surface of the bushing (1) is provided with a tank top flange (15). The outer surface of the bushing (1) is fitted with a centrifugal sling plate (2) by a tight fit, and an elastic self-compensating spiral sealing ring (3) is provided above the centrifugal sling plate (2). Positioning bosses (19) are symmetrically installed on both sides of the elastic self-compensating spiral sealing ring (3). The lower pressure cover (4) is fixed to the outside of the tank top flange (15) by bolts. The upper half of the elastic self-compensating spiral sealing ring (3) is embedded in the inner hole of the lower pressure cover (4). The boss (19) is inserted into the positioning groove corresponding to the inner hole of the lower pressure cover (4), and the lower half of the positioning boss (19) is embedded in the inner hole of the top flange (15) of the tank. The inner wall of the lower pressure cover (4) is provided with a liquid collection chamber (17), and a condensation guide ring (8) is installed above the liquid collection chamber (17). A three-way pipe fitting (5) is provided on one side of the bottom of the liquid collection chamber (17), and a transparent indicator tube (7) is installed on the top of the three-way pipe fitting (5). A return pipe (6) is provided at the bottom of the three-way pipe fitting (5), and a liquid outlet pipe (16) is installed on the side of the three-way pipe fitting (5) near the stirring shaft (14).

2. The mixing tank shaft end sealing device with a three-way reflux indicator assembly according to claim 1, characterized in that, The inside of the three-way fitting (5) is equipped with a miniature baffle (12) near the input end of the transparent indicator tube (7), and the end of the transparent indicator tube (7) is provided with a vent hole (13).

3. The mixing tank shaft end sealing device with a three-way reflux indicator assembly according to claim 1, characterized in that, The inner hole of the condensation guide ring (8) is provided with an annular sealing groove, and an auxiliary sealing ring (18) is installed inside the annular sealing groove.

4. The mixing tank shaft end sealing device with a three-way reflux indicator assembly according to claim 1, characterized in that, The elastic self-compensating spiral sealing ring (3) is made of modified polytetrafluoroethylene material, and the inner hole of the elastic self-compensating spiral sealing ring (3) is provided with a reverse spiral return groove, and the inner hole and the outer circle of the bushing (1) are elastically and dynamically clamped together.

5. A mixing tank shaft end sealing device with a three-way reflux indicator assembly according to claim 1, characterized in that, The centrifugal sling plate (2) is a truncated cone rotating body structure, and the centrifugal sling plate (2) is made of fluororubber material, and the plate surface of the centrifugal sling plate (2) is inclined downward from the near axis end to the far axis end.

6. The mixing tank shaft end sealing device with a three-way reflux indicator assembly according to claim 1, characterized in that, The connecting pipes between the tee fitting (5), return pipe (6), transparent indicator pipe (7), and outlet pipe (16) are all made of corrosion-resistant elastic material, and the pipes and the interfaces of the tee fitting (5) are connected by interference fit.

7. A mixing tank shaft end sealing device with a three-way reflux indicator assembly according to claim 1, characterized in that, The lower end face of the condensation guide ring (8) is an annular inclined surface, with the near-axial end of the annular inclined surface higher than the far-axial end, and the surface of the inclined surface is polished. The lowest edge of the condensation guide ring (8) is directly above the liquid collection chamber (17).

8. A mixing tank shaft end sealing device with a three-way reflux indicator assembly according to claim 7, characterized in that, The bushing (1) is fitted with a dustproof ring (11) that rotates synchronously with it. The transparent indicator tube (7) is vertically arranged on the outside of the lower pressure cover (4), and the outer wall of the transparent indicator tube (7) is marked with a preset warning line for judging the seal failure.

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