Dry gas sealing structure for autoclave

Abstract

The dry gas sealing structure comprises a spring seat, a main shaft, a movable ring, a static ring, a shaft sleeve, an inner gland and an outer gland, the shaft sleeve is sleeved on the main shaft, the movable ring is installed on the shaft sleeve through the spring seat, the movable ring is located in a high-pressure cavity formed by the inner gland and the outer gland, the cavity is connected with a sealing gas inlet, and the sealing gas inlet is connected with a sealing gas outlet. The static ring and the moving ring are correspondingly installed in a matched mode, the static ring is fixed to the outer gland, one or more sealing assemblies are arranged on the other side of the moving ring, the sealing structure can form a nitrogen cavity with positive pressure difference to isolate media from sealing and the environment, and zero leakage of the media is guaranteed. The defects that a traditional mechanical seal for the kettle is blocked by liquid, operation is complex, sealing liquid pollutes a process medium and the service life is short are overcome, and the service life can reach 25,000 hours.

Description

Technical Field

[0001] The utility model belongs to the technical field of dry gas sealing, and in particular relates to a dry gas sealing structure for an autoclave. Background Art

[0002] The polymerization kettle is a low-speed rotating equipment for high-pressure reactions. The medium sealed by its shaft seal is a gas-solid mixed medium. Traditional mechanical seals seal liquids to seal gas, which may lead to increased wear due to the gas-liquid mixed phase on the end face. Moreover, when the sealing liquid leaks into the kettle, it will pollute the products generated by the reaction.

[0003] Dry gas seal is a new type of shaft end seal that uses "gas blocking" instead of "liquid blocking". It is a non-contact seal. It mainly forms an air film when the sealing end face is running by adding a dynamic pressure groove on the dynamic ring of the mechanical seal and setting up a corresponding sealing gas auxiliary system. The non-contact operation of the sealing end face is achieved. The dry gas seal has the same balanced container structure as the general mechanical seal, but the end face design is different. There are grooves on the surface with a depth of several microns to more than ten microns, and the end face width is wider. Unlike general liquid-lubricated mechanical seals, dry gas seals produce a stable air film on the two sealing surfaces. This air film has a strong rigidity that completely separates the two sealing end faces and maintains a certain sealing gap. This gap cannot be too large, generally a few microns. If the sealing gap is too large, it will lead to increased leakage and poor sealing effect; while a small sealing gap will easily cause the two sealing surfaces to contact. Utility Model Content

[0004] In order to overcome the above-mentioned shortcomings, the inventor of the utility model has continuously reformed and innovated through long-term exploration and attempts, multiple experiments and efforts, and proposed a single-end dry gas sealing structure for low-speed and high-pressure polymerization reactors. The sealing structure is a combination of a front carbon ring seal and a single-sided dry gas seal. The sealing gas is nitrogen or a gas allowed by the process, and the pressure is higher than the medium pressure in the reactor. The carbon ring seal reduces the leakage of the sealing gas, and the sealing cavity formed with the single-end dry gas forms a positive pressure difference with the medium in the reactor, which will allow the sealing gas to form a flow barrier to the medium, ensuring zero leakage of the medium. There is only a small amount of safe sealing gas leakage on the outer dry gas sealing end face. It avoids the contamination of the process medium by the sealing oil used in traditional double-end mechanical seals, and also avoids the damage to the seal caused by frequent rehydration of the mechanical seal and other operational errors. The service life can reach 25,000 hours.

[0005] The technical solution adopted by the present utility model to achieve the above object is: to provide a dry gas seal structure for an autoclave. It includes a spring seat, a main shaft, a dynamic ring, a static ring, a shaft sleeve, an inner gland, and an outer gland. The shaft sleeve is sleeved on the main shaft, and the dynamic ring is installed on the shaft sleeve through the spring seat. The dynamic ring is located in the high-pressure cavity formed by the inner gland and the outer gland, and the cavity is connected to the sealing gas inlet. The static ring is installed corresponding to and matched with the dynamic ring, and the static ring is fixed on the outer gland. One or more sealing components are arranged on the other side of the dynamic ring.

[0006] According to a dry gas seal structure for an autoclave described in the present utility model, a further preferred technical solution is: the sealing component includes a carbon ring seat, a spring, and a carbon ring. The carbon ring seat is L-shaped, installed on the shaft sleeve and forming an annular space with the shaft sleeve. The opening of the annular space faces away from the dynamic ring. The carbon ring is sleeved on the shaft sleeve and located in the annular space. The carbon ring is limited by the bottom of the adjacent carbon ring seat or the end face of the inner gland. A spring is arranged between the carbon ring and the spring seat.

[0007] According to a dry gas seal structure for an autoclave described in the present utility model, a further preferred technical solution is: an installation hole is arranged on the carbon ring seat to install the spring. The spring is located at the bottom of the annular space. After the carbon ring is installed, the spring is in a compressed state so that there is a gap between the carbon ring and the carbon ring seat.

[0008] According to a dry gas seal structure for an autoclave described in the present utility model, a further preferred technical solution is: the thickness of the carbon ring is lower than the thickness of the annular space.

[0009] According to a dry gas seal structure for an autoclave described in the present utility model, a further preferred technical solution is: a fixing pin is arranged between the carbon ring and the carbon ring seat to fix the carbon ring on the carbon ring seat.

[0010] According to a dry gas seal structure for an autoclave described in the present utility model, a further preferred technical solution is: the spring seat includes a base, a sealing ring, and a snap ring. The base is sleeved on the shaft sleeve, and the lower part of the base is fixed on the shaft sleeve by screws. A U-shaped groove is arranged on the base, and the sealing ring is fixed in the U-shaped groove through the snap ring. The lower part of the dynamic ring is installed in the U-shaped groove and contacts the snap ring.

[0011] According to a dry gas seal structure for an autoclave described in the present utility model, a further preferred technical solution is: the static ring is set to be L-shaped, and an installation space is formed between the static ring and the shaft sleeve for fixing the outer gland on the positioning block.

[0012] According to a dry gas seal structure for an autoclave described in the present utility model, a further preferred technical solution is: the positioning block is arranged closely against the outer surface of the outer gland, and the positioning block is sleeved in the notch of the main shaft.

[0013] According to the dry gas sealing structure for an autoclave described in the utility model, a further preferred technical solution is that the mating surfaces of the static ring and the dynamic ring are both located in the high-pressure cavity, and the mating surface of the dynamic ring is higher than the end surface of the outer pressure cover where it is located.

[0014] According to the dry gas sealing structure for an autoclave described in the utility model, a further preferred technical solution is: the interior of the inner pressure cover is a three-section structure, which is a circular dynamic ring installation cavity, a sealing component installation cavity, and a sleeve installation hole with decreasing diameters from the front end to the rear end. The dynamic ring installation cavity serves as a part of the high-pressure cavity, and the sealing component installation cavity is used for the installation of the sealing component. The sealing component completely fills the sealing component installation cavity, and the sealing component is installed using the inner end of the sleeve installation hole.

[0015] Compared with the prior art, the technical solution of the utility model has the following advantages / benefits:

[0016] 1. Use pressurized sealing gas to replace pressurized sealing liquid to ensure "zero leakage" of process media. It can be used in all toxic and harmful media, crystallized coking media and ultra-low temperature media. It avoids the disadvantages of traditional kettle mechanical seals that use liquid blocking, complex operation, sealing liquid contamination of process media, and short service life. The service life can reach 25,000 hours, and the operating temperature range can reach -197℃~350℃. It avoids the contamination of process media by the sealing oil used in traditional double-end mechanical seals, and also avoids the damage to the seal caused by frequent fluid replenishment and other operating errors of mechanical seals. It is also suitable for agitators, centrifugal pumps, centrifugal fans, screw compressors, vacuum pumps, centrifugal separators and other equipment.

[0017] 2. Its sealing structure is a combination of a front carbon ring seal and a single-sided dry gas seal. The sealing structure can form a pressure-balanced nitrogen chamber to isolate the medium from the seal and the environment, ensuring zero leakage of the medium. The sealing gas is nitrogen or a gas allowed by the process, and the pressure is higher than the pressure of the medium in the kettle. The carbon ring seal reduces the leakage of the sealing gas, and the sealing cavity formed by the single-end dry gas forms a positive pressure difference with the medium in the kettle, which will allow the sealing gas to form a flow barrier to the medium, ensuring zero leakage of the medium. There is only a small amount of safe sealing gas leakage on the outer dry gas sealing end face. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the implementation mode of the utility model, the drawings required for use in the implementation mode will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 The utility model is a structural schematic diagram of a dry gas sealing structure for an autoclave.

[0020] Figure 2 is Figure 1 The partial enlarged view at position A in

[0021] Figure 3 is Figure 1 The partial enlarged view at position B in

[0022] The marks in the figure are respectively: 1. Spring seat, 101. Moving ring spring, 102. Base, 103. Sealing ring, 104. Snap ring, 2. Spindle, 3. Moving ring, 4. Static ring, 5. Bush, 6. Inner gland, 7. Outer gland, 8. Sealing assembly, 801. Carbon ring seat, 802. Spring, 803. Carbon ring, 804. Fixed pin, 805. Mounting hole, 9. Positioning block. Specific embodiments

[0023] To make the objectives, technical solutions and advantages of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model. Therefore, the detailed description of the embodiments of the present utility model provided below is not intended to limit the scope of the claimed present utility model, but merely represents the selected embodiments of the present utility model.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it may not be further defined and explained in subsequent figures.

[0025] Embodiment:

[0026] As Figures 1-3 shown, a dry gas seal structure for an autoclave. It includes a spring seat, a spindle 2, a moving ring 3, a static ring 4, a bush 5, an inner gland 6, and an outer gland 7. The bush 5 is sleeved on the spindle 2 and then installed on the spindle 2 by bolt connection. The moving ring 3 is installed on the bush 5 through the spring seat, that is, the moving ring 3 is fixed on the bush 5. The moving ring 3 is located in the high-pressure cavity formed by the inner gland 6 and the outer gland 7, and the cavity is connected to the sealing gas inlet. The static ring 4 is correspondingly and matingly installed with the moving ring 3, and the static ring 4 is fixed on the outer gland 7. Therefore, when the moving ring 3 with fluid dynamic pressure grooves on the outer side of the end face rotates, a gas film on the end face is formed. One or more sealing assemblies 8 are arranged on the other side of the moving ring 3, and the number of groups of the sealing assemblies 8 is set according to requirements. In this embodiment Figure 1Four sets of sealing devices are provided, and more can be provided when necessary to ensure sealing performance. The sealing assembly 8 includes a carbon ring seat 801, a spring, and a carbon ring. The carbon ring seat 801 is L-shaped, mounted on the shaft sleeve 5 and forms a circular ring space with the shaft sleeve 5. The opening of the circular ring space faces away from the dynamic ring 3. The carbon ring is sleeved on the shaft sleeve 5 and is located in the circular ring space. The carbon ring is limited by the bottom of the adjacent carbon ring seat 801 (the side facing the dynamic ring is the bottom) or the end face of the inner gland 6. A spring is provided between the carbon ring and the spring seat.

[0027] A mounting hole 805 is provided on the carbon ring seat 801 to mount the spring 802. The mounting hole 805 is located at the bottom of the circular ring space of the carbon ring seat 801 and is in the middle position as much as possible to balance the force. The spring 802 is located at the bottom of the circular ring space. After the carbon ring is installed, the spring 802 is in a compressed state so that there is a gap between the carbon ring and the carbon ring seat 801, so that the spring can have a certain degree of micro-motion ability, so that the sealing state can be maintained in good condition.

[0028] The thickness of the carbon ring 803 is lower than the thickness of the annular space, so that the carbon ring 803 can have a movement gap in the annular space, and the spring 802 also has an installation movement space.

[0029] A fixing pin 804 is provided between the carbon ring and the carbon ring seat 801 to fix the carbon ring on the carbon ring seat 801, mainly to prevent the spring from rotating and to avoid excessive changes in the installation position of the spring or carbon ring, which would affect the sealing performance. Of course, the fixing pin is only a relatively simple method, and positioning grooves and other methods can also be used.

[0030] The spring seat includes a base 102, a sealing ring 103, and a retaining ring 104. The base 102 is sleeved on the shaft sleeve 5. The lower part of the base 102 is fixed to the shaft sleeve 5 by screws. A U-shaped groove is provided on the base 102. The sealing ring 103 is fixed in the U-shaped groove by the retaining ring 104. The lower part of the dynamic ring 3 is installed in the U-shaped groove and contacts with the retaining ring. A dynamic ring spring 101 is provided in the U-shaped groove and is located between the bottom of the retaining ring and the base.

[0031] The stationary ring 4 is configured to be L-shaped (a protruding sleeve is configured in an annular structure), and an installation space is formed between the stationary ring 4 and the shaft sleeve 5, which is used to fix the outer pressure cover 7 on the positioning block 9. The L-shape is configured to enhance the installation strength, and also to leave installation space for bolts for the connection between the outer pressure cover 7 and the positioning block 9.

[0032] The positioning block 9 is arranged closely against the outer surface of the outer pressure cover 7, and the positioning block 9 is sleeved in the notch of the main shaft 2, that is, the key structure is used for installation and positioning.

[0033] The mating surfaces of the stationary ring 4 and the rotating ring 3 are both located in the high-pressure cavity, and the mating surface of the rotating ring 3 protrudes from the end face of the outer gland 7 at its location, so that the filled isolating gas is pumped into the isolation surface by the hydrodynamic grooves.

[0034] The interior of the inner gland 6 has a three-section structure. From the front end to the rear end, there are a rotating ring 3 installation cavity with gradually decreasing diameters in a circular shape, a sealing assembly 8 installation cavity, and a shaft sleeve 5 installation hole. The rotating ring 3 installation cavity is part of the high-pressure cavity. The sealing assembly 8 installation cavity is for the installation of the sealing assembly 8. The sealing assembly 8 completely fills the sealing assembly 8 installation cavity, and the inner end of the shaft sleeve 5 installation hole is used to install the sealing assembly 8. That is, the structure at the shaft sleeve 5 installation hole is also an L-shaped structure for limiting the position of the carbon ring.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0036] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The above are only the preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as a limitation to the present invention. The protection scope of the present invention should be subject to the scope defined by the claims. For those of ordinary skill in the art, without departing from the spirit and scope of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. A dry gas sealing structure for an autoclave, characterized in that: It includes a spring seat, a main shaft, a dynamic ring, a static ring, a sleeve, an inner pressure cover, and an outer pressure cover. The sleeve is mounted on the main shaft, and the dynamic ring is installed on the sleeve through the spring seat. The dynamic ring is located in a high-pressure cavity formed by the inner pressure cover and the outer pressure cover, and the cavity is connected to a sealing gas inlet. The static ring is installed in a corresponding matching manner with the dynamic ring, and the static ring is fixed on the outer pressure cover. One or more sealing components are arranged on the other side of the dynamic ring.

2. A dry gas sealing structure for an autoclave according to claim 1, characterized in that: The sealing assembly includes a carbon ring seat, a spring, and a carbon ring. The carbon ring seat is L-shaped, installed on the shaft sleeve and forms a circular ring space with the shaft sleeve. The opening of the circular ring space faces away from the dynamic ring. The carbon ring is sleeved on the shaft sleeve and is located in the circular ring space. The carbon ring is limited by the bottom of the adjacent carbon ring seat or the end face of the inner pressure cover. A spring is arranged between the carbon ring and the spring seat.

3. A dry gas sealing structure for an autoclave according to claim 2, characterized in that: A mounting hole is arranged on the carbon ring seat to mount a spring, and the spring is located at the bottom of the annular space. After the carbon ring is mounted, the spring is in a compressed state so that a gap exists between the carbon ring and the carbon ring seat.

4. A dry gas sealing structure for an autoclave according to claim 2, characterized in that: The thickness of the carbon ring is lower than the thickness of the annular space.

5. The dry gas sealing structure for an autoclave according to claim 2, characterized in that: A fixing pin is arranged between the carbon ring and the carbon ring seat to fix the carbon ring on the carbon ring seat.

6. The dry gas sealing structure for an autoclave according to claim 1, characterized in that: The spring seat includes a base, a sealing ring, and a retaining ring. The base is sleeved on the shaft sleeve. The lower part of the base is fixed to the shaft sleeve by screws. A U-shaped groove is provided on the base. The sealing ring is fixed in the U-shaped groove by a retaining ring. The lower part of the dynamic ring is installed in the U-shaped groove and contacts with the retaining ring.

7. The dry gas sealing structure for an autoclave according to claim 1, characterized in that: The stationary ring is configured in an L shape, and a mounting space is formed between the stationary ring and the shaft sleeve for fixing the outer pressure cover on the positioning block.

8. The dry gas sealing structure for an autoclave according to claim 7, characterized in that: The positioning block is arranged closely against the outer surface of the outer pressure cover, and the positioning block is sleeved in the notch of the main shaft.

9. The dry gas sealing structure for an autoclave according to claim 1, characterized in that: The mating surfaces of the static ring and the dynamic ring are both located in the high-pressure cavity, and the mating surface of the dynamic ring is higher than the end surface of the outer pressure cover where it is located.

10. The dry gas sealing structure for an autoclave according to claim 7, characterized in that: The interior of the inner pressure cover is a three-section structure, which includes a circular dynamic ring installation cavity, a sealing assembly installation cavity, and a sleeve installation hole, each of which has a decreasing diameter from the front end to the rear end. The dynamic ring installation cavity serves as a part of the high-pressure cavity, and the sealing assembly installation cavity is used for the installation of the sealing assembly. The sealing assembly completely fills the sealing assembly installation cavity, and the sealing assembly is installed using the inner end of the sleeve installation hole.

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