Sealing device for shaft

Abstract

The utility model discloses a sealing device for a shaft, which is used for axial sealing of a liquid storage tank at a rotating shaft and comprises a single-end-face mechanical sealing structure, a mounting flange and a packing sealing structure which are sequentially arranged along the direction of a central shaft of the rotating shaft, the single-end-face mechanical sealing structure is arranged on the inner side of the liquid storage tank, and the packing sealing structure is arranged on the outer side of the liquid storage tank. The mounting flange is used for being connected with a butt flange on the liquid storage tank. A first sealing cavity is defined by a friction pair composed of the movable ring assembly and the static ring assembly, the movable ring base and the static ring base, lubricating grease is guided into the first sealing cavity through the grease nipple and the lubricating grease filling port, a second sealing cavity is formed between the woven sealing filler and the shaft sleeve, and secondary sealing can be conducted on a leakage point while the sealing leakage condition can be monitored. The sealing device is also particularly suitable for working conditions with a larger temperature change range, such as high-temperature molten salt filtering equipment, and can lock the woven graphite filler even under the high-temperature working condition of 200-480 DEG C, so that the complete sealing between the shaft and the container is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of sealing, in particular to a shaft sealing device. Background Art

[0002] At present, there are not many dynamic sealing devices suitable for high temperature in the chemical industry. They are mainly composed of four parts: sealing rings (dynamic and static rings), buffer compensation mechanism, auxiliary sealing ring, and transmission mechanism. The dynamic ring is fixedly connected to the dynamic ring seat and sleeved on the rotating shaft to move with the rotating shaft. One end face of the dynamic ring is the dynamic ring sealing surface. The dynamic ring sealing surface and the static ring sealing surface abut each other to form a rotating sealing connection; the other end of the dynamic ring abuts the push ring, which is sleeved with the spring and abuts in the spring seat. The spring pushes the push ring and the static ring to maintain the abutment pressure. Although the axial sealing effect can be achieved, there is still a risk that it will gradually deteriorate after leakage until a large-scale leakage occurs, and the service life is particularly affected by the working conditions. Especially when used in a corrosive environment, the leakage may cause irreversible damage to the structure of the main equipment and the surrounding environment, reducing the service life of the mechanical seal structure. Summary of the invention

[0003] The utility model aims to provide a shaft sealing device, so as to solve the problem of large-area leakage caused by the weakening of the spring compensation effect of the single-end mechanical seal structure or the excessive radial swing of the rotating shaft resulting in the crushing of the sealing surface in the prior art.

[0004] In order to solve the above problems, the utility model adopts the following technical solutions:

[0005] The utility model provides a shaft sealing device, which is used for axial sealing of a liquid storage tank at a rotating shaft, and comprises: a single-end mechanical sealing structure, a mounting flange, and a packing sealing structure which are arranged in sequence along the central axis direction of the rotating shaft, wherein the single-end mechanical sealing structure is arranged on the inner side of the liquid storage tank, and the packing sealing structure is arranged on the outer side of the liquid storage tank; wherein the single-end mechanical sealing structure comprises: a dynamic ring seat, a push ring assembly, a dynamic ring assembly, a static ring assembly, a static ring seat, an isolating ring, a bolt connection assembly, and a plurality of compression springs, wherein the dynamic ring assembly is sleeved on the dynamic ring seat and rotates synchronously with the rotating shaft, the static ring assembly is sleeved on the static ring seat, the plurality of compression springs are uniformly arranged on the dynamic ring seat along the circumferential direction, the push ring assembly pushes the dynamic ring assembly through the compression spring, and the connection between the dynamic ring assembly and the static ring assembly The contact surfaces slide relative to each other and always remain in contact; the mounting flange comprises: a mechanical seal connecting flange, a stuffing box, a liner, and a flange body, the stuffing box having a stuffing filling space open upward, the stuffing box being provided with a grease nipple for the introduction and export of grease, the mechanical seal connecting flange and the single-end mechanical seal structure being fixedly connected via a bolt connection assembly; the stuffing sealing structure comprises: a shaft sleeve, a braided sealing packing, a split pressure ring, a stuffing box gland, and a bolt connection assembly, the shaft sleeve being sleeved on the rotating shaft, the braided sealing packing being filled in the stuffing box, the stuffing sealing ring being used to separate adjacent braided sealing packings, the stuffing box gland locking the braided sealing packing from above via the split pressure ring, and the stuffing box gland and the flange body being fixedly connected via a bolt connection assembly.

[0006] Preferably, one end of the compression spring abuts against the push ring assembly, and the other end abuts against the dynamic ring seat, ensuring that the compression spring is always reliably fixed and pushed in a compressed state, and facilitating the installation and positioning of the spring.

[0007] Preferably, a dynamic ring seat sealing ring is provided between the dynamic ring seat and the rotating shaft, a dynamic ring sealing ring is provided between the dynamic ring assembly and the dynamic ring seat, a sleeve sealing ring is provided between the sleeve and the rotating shaft, and a stationary ring sealing ring is provided between the stationary ring assembly and the stationary ring seat. According to a preferred embodiment of the utility model, these sealing rings are all O-rings. The arrangement of the above-mentioned sealing rings prevents liquid from leaking through the fitting gap, thereby realizing an auxiliary sealing function.

[0008] Preferably, the dynamic ring seat is connected to the rotating shaft via a set screw, and the contact pressure between the dynamic and static rings can be flexibly adjusted according to requirements.

[0009] Preferably, the mechanical seal connecting flange, stuffing box, liner and flange body are formed into one piece by welding to ensure the coaxiality of the mounting flange and the rotating shaft.

[0010] Preferably, the dynamic ring assembly and the static ring assembly are both made of silicon carbide hard friction ring material, and the friction pair formed by the two, together with the dynamic ring seat and the static ring seat, form a first sealing cavity to form a first seal.

[0011] Preferably, the packing seal ring is further provided with a grease filling port, which plays an auxiliary sealing and lubricating role when the rotating shaft and the braided seal packing rotate relative to each other, and forms a second sealing cavity between the braided seal packing and the sleeve, forming a second seal.

[0012] Preferably, the stationary ring assembly and the stationary ring seat are fixed by an anti-rotation pin to prevent the stationary ring assembly from radially rotating.

[0013] Preferably, the bolt connection assembly comprises: a screw rod, a nut, and an elastic washer.

[0014] Preferably, a cooling cavity through which a cooling water circuit can pass is provided in the flange body to prevent the shaft sealing device from having an excessively high temperature at that location.

[0015] According to a preferred embodiment of the present invention, the diameter of the rotating shaft is preferably 35-40 mm, and most preferably 38 mm, and the material of the rotating shaft is preferably C276 Hastelloy. If the shaft diameter is too small (less than 32 mm), the rotating shaft may bend at high temperatures, and if the shaft diameter is too large (more than 50 mm), the overall sealing structure cost will increase.

[0016] According to a preferred embodiment of the present invention, the new shaft sealing device can also be used in high-temperature molten salt filtering equipment. For details, please refer to a filter element device, a filter and its application disclosed in application number "202010905020.9". When the new shaft sealing device is used in high-temperature molten salt filtering equipment, it can meet the equipment sealing requirements under high-temperature conditions of 200°C to 480°C in high-temperature molten salt filtration. The new shaft sealing device can ensure that the rotating shaft has no deflection under high-temperature conditions, is resistant to molten salt vapor corrosion, and acts as a push rod to compress the filter element in the high-temperature molten salt filter.

[0017] According to the inventor's research, when filtering high-temperature molten salt (550°C), the bottom of the rotating shaft contacts the molten salt, and the entire shaft will show a temperature gradient change due to heat conduction and heat radiation. According to calculations and actual measurements, the temperature at the sealing structure is >200°C. To ensure the sealing life under continuous high temperatures, a forced cooling function must be added. Therefore, a cooling chamber with a cooling water channel is provided in the mounting flange to meet the cooling requirements of single-end seals and packing seals, and also avoids the problem of seal failure under high-temperature conditions.

[0018] One of the inventive points of the shaft sealing device is that, in order to better isolate the container from the external environment during the transportation and filtration of high-temperature molten salt, the flange body of the mounting flange has a built-in cooling cavity and a cooling water path, thereby effectively preventing the sealing structure from overheating. This not only meets the requirement that the shaft can be rotated during filter element replacement at low temperatures, but also meets the isolation and sealing of the inert gas in the container after the temperature rises. The integrated design achieves the effect of frequent disassembly and assembly without affecting the sealing performance.

[0019] Compared with the prior art, the advantages of the utility model mainly lie in the combination of mechanical seal structure and packing seal, which can be applied to the sealing requirements of special working conditions, especially to working conditions with a large temperature change range, such as 200℃~480℃ in high-temperature molten salt filtration. Under high-temperature working conditions, the braided graphite packing is locked to achieve complete sealing between the shaft and the container. When there is a rotation demand at low temperature, the single-end mechanical seal takes effect.

[0020] Compared with the prior art, the shaft sealing device provided by the utility model has the following beneficial effects:

[0021] 1) A packing seal structure is further added on the basis of the single-end mechanical seal structure and the mounting flange. The first seal is formed by the single-end mechanical seal structure, and the second seal is formed by the packing seal structure. Once the storage tank leaks or pressure leaks, it can be directly judged that the first internal dynamic and static ring seal structure has failed, and the packing seal gland is locked in time until the operation is stopped for maintenance. After the liquid in the tank is discharged, the single-end mechanical seal structure is replaced, avoiding losses caused by large-area leakage;

[0022] 2) The sealing effect is good, the vibration and deformation of the rotating shaft are small, the dynamic ring and the static ring are balanced, which is convenient for disassembly and maintenance, and the sealing condition can be monitored online, thereby extending the service life of the shaft sealing device and the liquid storage tank;

[0023] 3) Install sealing rings at all possible leakage points, i.e., at the fitting gaps, to ensure the sealing effect;

[0024] 4) A cooling cavity with cooling water passage is set in the mounting flange to meet the cooling requirements of single-end seal and packing seal, avoiding the problem of seal failure in high-temperature working conditions, and is particularly suitable for working conditions with a large temperature change range;

[0025] 5) Reasonable structural design, simple operation, saving maintenance time.

[0026] In summary, the utility model provides a shaft sealing device which can monitor the leakage status of the seal, perform secondary sealing on the leakage point, effectively prevent the seal structure from overheating, and has a prolonged service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic structural diagram of a shaft sealing device provided according to a preferred embodiment of the utility model;

[0028] In the figure, the meanings of the reference numerals are as follows:

[0029] 1-Single-end mechanical seal structure; 2-Mounting flange; 3-Packing seal structure; 4-Grease nipple; 5-Rotating shaft; 1.1-Dynamic ring seat; 1.2-Dynamic ring seat seal ring; 1.3-Push ring assembly; 1.4-Dynamic ring seal ring; 1.5-Dynamic ring assembly; 1.6-Stationary ring assembly; 1.7-Stationary ring seat; 1.8-Stationary ring seal ring; 1.9-Anti-rotation pin; 1.10-Isolation ring; 1.11-Bolt connection assembly; 1.12-Compression spring; 2.1-Mechanical seal connection flange; 2.2-Stuffing box; 2.3-Liner; 2.4-Flange body; 3.1-Seal ring; 3.2 Bushing; 3.3-Seal packing; 3.4-Split pressure ring; 3.5-Stuffing box cover; 3.6-Bolt connection assembly. DETAILED DESCRIPTION

[0030] The following is a further explanation of the present invention in conjunction with specific implementation cases. It should be understood that the following examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional operations in the art.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0032] like Figure 1 As shown, a shaft sealing device provided according to a preferred embodiment of the utility model is used for axial sealing of a liquid storage tank at a rotating shaft 5, the rotating shaft 5 extending along a central axis, and the shaft sealing device comprises a single-end mechanical sealing structure 1, a mounting flange 2, and a packing sealing structure 3 sequentially arranged along the central axis direction of the rotating shaft 5. The single-end mechanical sealing structure 1 is arranged on the inner side of the liquid storage tank, the packing sealing structure 3 is arranged on the outer side of the liquid storage tank, and the mounting flange 2 is used for connection with a docking flange (not shown) on the liquid storage tank.

[0033] The single-end mechanical seal structure 1 includes: a dynamic ring seat 1.1, a dynamic ring seat sealing ring 1.2, a push ring assembly 1.3, a dynamic ring sealing ring 1.4, a dynamic ring assembly 1.5, a stationary ring assembly 1.6, a stationary ring seat 1.7, a stationary ring sealing ring 1.8, an anti-rotation pin 1.9, an isolation ring 1.10, a bolt connection assembly 1.11, and a plurality of compression springs 1.12. The grooved upper part of the moving ring assembly 1.5 is sleeved on the moving ring seat 1.1 and rotates synchronously with the rotating shaft 5. The grooved upper part of the stationary ring assembly 1.6 is sleeved on the stationary ring seat 1.7. A number of compression springs 1.12 are evenly arranged on the moving ring seat 1.1 along the circumference. One end of the compression spring 1.12 abuts against the push ring assembly 1.3, and the other end abuts against the moving ring seat 1.1, ensuring that the compression spring 1.12 is always reliably fixed and pushed in a compressed state. The push ring assembly 1.3 pushes the moving ring assembly 1.5 through the compression spring 1.12. The contact surfaces of the moving ring assembly 1.5 and the stationary ring assembly 1.6 slide relative to each other and always remain in contact. The stationary ring assembly 1.6 is fixed to the stationary ring seat 1.7 by an anti-rotation pin 1.9 to prevent the stationary ring assembly 1.6 from radially rotating. The bolt connection assembly 1.11 includes: a screw, a nut, and an elastic washer.

[0034] The mounting flange 2 comprises: a mechanical seal connection flange 2.1, a stuffing box 2.2, a lining plate 2.3, and a flange body 2.4. The stuffing box 2.2 has a stuffing filling space open upwards, and a grease nipple 4 is also provided on the stuffing box 2.2 for introducing and exporting grease. The mechanical seal connection flange 2.1 and the single-end mechanical seal structure 1 are fixedly connected by a bolt connection assembly 1.11. A cooling cavity is preferably provided in the flange body 2.4, through which a cooling water path can pass, so as to prevent the shaft sealing device from overheating.

[0035] The packing seal structure 3 includes: a packing seal ring 3.1, a sleeve 3.2, a braided seal packing 3.3, a split pressure ring 3.4, a packing box gland 3.5, and a bolt connection assembly 3.6. Among them, the sleeve 3.2 is sleeved on the rotating shaft 5, the braided seal packing 3.3 is filled in the packing box 2.2, the packing seal ring 3.1 is used to separate adjacent braided seal packings 3.3, and a grease filling port connected to the grease nipple 4 is also added at a suitable position on the packing seal ring 3.1 to fill grease for the upper and lower braided seal packings 3.3, so as to play an auxiliary sealing and lubrication role when the rotating shaft 5 and the braided seal packing 3.3 rotate relative to each other. The packing box gland 3.5 locks the braided seal packing 3.3 from the top through the split pressure ring 3.4, and the packing box gland 3.5 and the flange body 2.4 are fixedly connected by the bolt connection assembly 3.6.

[0036] According to this preferred embodiment, a dynamic ring seat sealing ring 1.2 is provided between the dynamic ring seat 1.1 and the rotating shaft 5, a dynamic ring sealing ring 1.4 is provided between the dynamic ring assembly 1.5 and the dynamic ring seat 1.1, a sleeve sealing ring is provided between the sleeve 3.2 and the rotating shaft 5, and a stationary ring sealing ring 1.8 is provided between the stationary ring assembly 1.6 and the stationary ring seat 1.7. The arrangement of these sealing rings prevents liquid from leaking through the fitting gap, thereby realizing an auxiliary sealing function.

[0037] According to this preferred embodiment, the dynamic ring seat 1.1 is connected to the rotating shaft 5 via a set screw, so the contact pressure between the dynamic and static rings can be flexibly adjusted according to requirements.

[0038] According to the preferred embodiment, both the dynamic ring assembly 1.5 and the static ring assembly 1.6 are made of silicon carbide hard friction ring material.

[0039] According to the shaft sealing device provided in the above preferred embodiment, the installation method thereof is as follows:

[0040] First, the single-end mechanical seal structure 1 is pre-assembled into a whole;

[0041] Then, the mounting flange 2 is also pre-assembled and welded into a whole to ensure the coaxiality between the mounting flange 2 and the rotating shaft 5;

[0042] Next, the single-end mechanical seal structure 1 is fixedly connected to the mounting flange 2 through the bolt connection assembly 1.11, and then connected to the docking flange of the liquid storage tank through the flange body 2.4, and the rotating shaft 5 is installed after adjusting the position;

[0043] Then, the shaft sleeve 3.2 is sleeved on the rotating shaft 5 by means of a set screw, the braided sealing packing 3.3 is sequentially filled into the stuffing box 2.2, and the adjacent braided sealing packings 3.3 are spaced apart by means of a stuffing sealing ring 3.1, and then the split pressing ring 3.4 and the stuffing box gland 3.5 are sequentially installed, and finally the stuffing box gland 3.5 is fixedly connected to the flange body 2.4 by means of a bolt connection assembly 3.6;

[0044] Grease is introduced through the grease nipple 4 on the stuffing box 2.2 and the grease filling port on the stuffing seal ring 3.1 to maintain the lubrication state and sealing in the stuffing seal working chamber while ensuring that the pressure in the sealing chamber is always higher than the pressure in the container, so that the stuffing seal is in an effective sealing state.

[0045] In summary, according to the shaft sealing device provided by the utility model, the friction pair composed of the dynamic ring assembly and the static ring assembly, the dynamic ring seat and the static ring seat together form a first sealing chamber, and the grease is introduced through the grease nipple and the grease filling port to form a second sealing chamber between the braided sealing packing and the sleeve. During the operation of the rotating equipment, once the liquid storage tank leaks or pressure leaks, it can be directly judged that the first internal dynamic and static ring sealing structure has failed. By timely locking the packing sealing gland until the operation is stopped for maintenance, the single-end mechanical sealing structure is replaced after the liquid in the tank is discharged. The shaft sealing device has the characteristics of reasonable design, practical structure, convenient operation, easy production and low cost. It not only greatly saves the time for inspection and maintenance, but also can timely monitor and solve the problems of short life and large-area leakage of the single-end mechanical sealing structure, and the use effect is obvious.

[0046] The above is only a preferred embodiment of the utility model, and is not intended to limit the scope of the utility model. The above embodiments of the utility model can also be modified in various ways. All simple, equivalent changes and modifications made according to the claims and the contents of the specification of the utility model application fall within the scope of protection of the claims of the utility model patent. The conventional technical contents are not described in detail in the utility model.

Claims

1. A shaft sealing device, characterized in that: A device for axially sealing a liquid storage tank at a rotating shaft (5), comprising a single-end mechanical seal structure (1), a mounting flange (2), and a packing seal structure (3) which are sequentially arranged along the central axis direction of the rotating shaft (5); the single-end mechanical seal structure (1) is arranged on the inner side of the liquid storage tank, the packing seal structure (3) is arranged on the outer side of the liquid storage tank, and the mounting flange (2) is used for connecting with a docking flange on the liquid storage tank; wherein: The single-end mechanical seal structure (1) comprises: a moving ring seat (1.1), a push ring assembly (1.3), a moving ring assembly (1.5), a stationary ring assembly (1.6), a stationary ring seat (1.7), an isolating ring (1.10), a bolt connection assembly (1.11), and a plurality of compression springs (1.12); the moving ring assembly (1.5) is sleeved on the moving ring seat (1.1) and rotates synchronously with the rotating shaft (5); the stationary ring assembly (1.6) is sleeved on the stationary ring seat (1.7); the plurality of compression springs (1.12) are evenly arranged on the moving ring seat (1.1) along the circumferential direction; the push ring assembly (1.3) pushes the moving ring assembly (1.5) through the compression springs (1.12); the contact surfaces of the moving ring assembly (1.5) and the stationary ring assembly (1.6) slide relative to each other and always remain in contact; The mounting flange (2) comprises: a mechanical seal connection flange (2.1), a stuffing box (2.2), a lining plate (2.3), and a flange body (2.4); the stuffing box (2.2) has a stuffing filling space that is open upward; a grease nipple (4) is provided on the stuffing box (2.2) for introducing and exporting grease; the mechanical seal connection flange (2.1) and the single-end mechanical seal structure (1) are fixedly connected via a bolt connection assembly (1.11); The packing seal structure (3) comprises: a packing seal ring (3.1), a shaft sleeve (3.2), a braided seal packing (3.3), a split pressure ring (3.4), a packing box cover (3.5), and a bolt connection assembly (3.6); the shaft sleeve (3.2) is sleeved on the rotating shaft (5); the braided seal packing (3.3) is filled in the packing box (2.2); the packing seal ring (3.1) is used to separate adjacent braided seal packings (3.3); the packing box cover (3.5) locks the braided seal packing (3.3) from above via the split pressure ring (3.4); and the packing box cover (3.5) and the flange body (2.4) are fixedly connected via a bolt connection assembly (3.6).

2. The shaft sealing device according to claim 1, characterized in that: One end of the compression spring (1.12) abuts against the push ring assembly (1.3), and the other end abuts against the moving ring seat (1.1), ensuring that the compression spring (1.12) is always reliably fixed and pushed in a compressed state.

3. The shaft sealing device according to claim 1, characterized in that: A dynamic ring seat sealing ring (1.2) is provided between the dynamic ring seat (1.1) and the rotating shaft (5), a dynamic ring sealing ring (1.4) is provided between the dynamic ring assembly (1.5) and the dynamic ring seat (1.1), a shaft sleeve sealing ring is provided between the shaft sleeve (3.2) and the rotating shaft (5), and a static ring sealing ring (1.8) is provided between the static ring assembly (1.6) and the static ring seat (1.7). The provision of the above-mentioned sealing rings prevents liquid from leaking through the fitting gap, thereby realizing an auxiliary sealing function.

4. The shaft sealing device according to claim 1, characterized in that: The dynamic ring seat (1.1) is connected to the rotating shaft (5) via a set screw, and the contact pressure between the dynamic and static rings can be flexibly adjusted according to demand.

5. The shaft sealing device according to claim 1, characterized in that: The mechanical seal connecting flange (2.1), the stuffing box (2.2), the lining plate (2.3), and the flange body (2.4) are formed into one piece by welding, thereby ensuring the coaxiality of the mounting flange (2) and the rotating shaft (5).

6. The shaft sealing device according to claim 1, characterized in that: The friction pair formed by the dynamic ring assembly (1.5) and the stationary ring assembly (1.6), the dynamic ring seat (1.1) and the stationary ring seat (1.7) together enclose a first sealing cavity.

7. The shaft sealing device according to claim 1, characterized in that: The packing seal ring (3.1) is also provided with a grease filling port, which plays an auxiliary sealing and lubricating role when the rotating shaft (5) and the braided seal packing (3.3) rotate relative to each other, and forms a second sealing cavity between the braided seal packing (3.3) and the shaft sleeve (3.2).

8. The shaft sealing device according to claim 1, characterized in that: The stationary ring assembly (1.6) and the stationary ring seat (1.7) are fixed via an anti-rotation pin (1.9) to prevent the stationary ring assembly (1.6) from rotating radially.

9. The shaft sealing device according to claim 1, characterized in that: The diameter of the rotating shaft (5) is 35-40 mm, and the material of the rotating shaft (5) is C276 Hastelloy.

10. The shaft sealing device according to claim 1, characterized in that: A cooling cavity through which a cooling water path can pass is arranged in the flange body (2.4) to prevent the shaft sealing device from overheating.

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