Combined sealing structure

Abstract

The combined sealing structure comprises a shell, a shaft sleeve, a static ring, a spring, a tooth type sealing piece, a spring piece, an electromagnetic coil, a ferromagnetic pole shoe and magnetic fluid, the shaft sleeve is fixedly connected to a rotor in the side, close to the atmosphere, of the shell, the static ring is connected to the inner side face of the shaft sleeve, and the spring is arranged between the static ring and the inner left wall of the shell; a ferromagnetic pole shoe and an electromagnetic coil are arranged between one side, close to the interior of the equipment, of the shell and the rotor, and a magnetic fluid seal is arranged between the ferromagnetic pole shoe and the rotor; a tooth-shaped sealing piece is installed between the middle of the shell and the rotor, and the tooth-shaped sealing piece is fixed to the inner side of the shell through a spring piece. According to the combined sealing structure, the pole shoe can be protected under the condition that the radial movement of the rotor is large, and the interior of equipment is kept sealed under the condition of power failure.

Description

Technical Field

[0001] This invention belongs to the field of sealing technology for rotating shaft structures, specifically a combined sealing structure. Background Technology

[0002] Existing magnetohydrodynamic sealing technology structures such as Figure 1 As shown. The traditional magnetohydrodynamic sealing structure consists of a housing 21, a sealing ring 22, an electromagnetic coil 23, a ferromagnetic pole shoe 24, a front baffle 25, and a magnetohydrodynamic fluid 26. Figure 1 The left side of the magnetohydrodynamic sealing structure is the atmosphere, and the right side is the sealing medium.

[0003] In practical applications, electromagnetic coils are often used instead of permanent magnets. This is because electromagnetic coils offer dynamic adjustability, allowing for precise adjustment of the magnetic field strength by regulating the current when the internal sealing medium pressure changes, thereby altering the pressure-bearing capacity of the magnetohydrodynamic seal. However, they also have the problem of immediate coil failure upon power failure, leading to seal failure. Therefore, it is essential to ensure the electromagnetic coil is always energized during equipment shutdown.

[0004] Meanwhile, when the rotor axial movement is large, the pole shoes are prone to rubbing against the equipment rotor, leading to pole shoe damage (such as the low-temperature large-diameter magnetic fluid sealing device disclosed in patent CN1544834A), which in turn leads to damage and replacement of the magnetic fluid sealing structure. Although methods such as increasing the dynamic and static clearance and widening the pole shoe sealing surface have been used in actual use to improve this problem, this also causes a decrease in sealing pressure. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a combined sealing structure that can protect the pole shoes when the rotor radial movement is large, and maintain the internal seal of the equipment in the event of a power failure.

[0006] To achieve the above objectives, the technical solution of the present invention is: a combined sealing structure, comprising a housing, a bushing, a stationary ring, a spring, a toothed seal, a spring plate, an electromagnetic coil, a ferromagnetic pole shoe, and a magnetic fluid. The bushing is fixedly connected to the rotor on the side of the housing closest to the atmosphere. A stationary ring is connected to the inner side of the bushing, and a spring is provided between the stationary ring and the left inner wall of the housing. A ferromagnetic pole shoe and an electromagnetic coil are installed between the housing and the rotor on the side of the housing closest to the equipment interior, and a magnetic fluid seal is provided between the ferromagnetic pole shoe and the rotor. A toothed seal is installed between the housing and the rotor in the middle of the housing, and the toothed seal is fixed to the inner side of the housing by a spring plate.

[0007] Furthermore, the housing adopts a split-face mounting structure.

[0008] Furthermore, the bushing is fixed to the rotor by a rectangular key.

[0009] Furthermore, a sealing ring is installed between the bushing and the rotor to ensure a seal at that location.

[0010] Furthermore, the end face of the bushing is machined with a dynamic pressure groove, and the bushing and the stationary ring are subjected to grinding and polishing to form a sliding seal fit.

[0011] Furthermore, the distance between the tooth tip of the toothed seal and the rotor is less than the distance between the ferromagnetic pole shoe and the rotor.

[0012] Furthermore, a sealing ring is installed between the ferromagnetic pole shoe and the housing to ensure a seal at that location.

[0013] Furthermore, the magnetohydrodynamic seal utilizes an electromagnet to generate a strong magnetic field in the sealing gap between the rotor and the ferromagnetic pole shoe, attracting the magnetized sealant to the tooth end of the ferromagnetic pole shoe where the magnetic field strength is highest.

[0014] Furthermore, when the rotor rotates, the bushing rotates with the rotor, and an air film is formed between the bushing and the stationary ring, compressing the spring; when the rotor stops, the air film disappears, and the bushing and the stationary ring are tightly connected, ensuring a seal in the static state.

[0015] Furthermore, when the rotor radial movement is large, the toothed seal first contacts the rotor, the rotor pushes the toothed seal inward, and then the rotor returns to its original position under the force of the spring plate, ensuring that the ferromagnetic material does not collide with the rotor.

[0016] Compared with the prior art, the present invention has the following significant advantages: When the rotor rotates, the bushing rotates with the rotor, forming an air film between the bushing and the stationary ring, compressing the spring. After the rotor comes to a stop, the air film disappears, and the moving and stationary rings are tightly connected, ensuring the structure is sealed when stationary.

[0017] When the rotor radial movement is large, the toothed seal first contacts the rotor, the rotor pushes the toothed seal inward, and then the rotor returns to its original position under the force of the spring plate, ensuring that the pole shoe will not collide with the rotor.

[0018] The small gap between the rotating and stationary rings during operation makes them highly susceptible to damage from foreign matter, leading to the failure of the air wedge effect. When the magnetohydrodynamic seal fails during normal operation due to cooling failure, depletion of the magnetohydrodynamic fluid, or power outage, the working fluid will impact the outside along with the broken magnetohydrodynamic fluid. The toothed seal acts as a physical seal, buffering the impact between the working fluid and the magnetohydrodynamic fluid. This ensures the safety of the rotating and stationary rings under special operating conditions and ensures that the equipment remains sealed internally and externally after an emergency shutdown of the unit. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a traditional magnetohydrodynamic sealing structure; Figure 2 This is a schematic diagram of the combined sealing structure of the present invention. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0021] like Figure 2 As shown, a combined sealing structure of the present invention comprises a housing 1, a bushing 2, a stationary ring 3, a spring 4, a toothed seal 5, a spring plate 6, a sealing ring 7, an electromagnetic coil 8, a ferromagnetic pole shoe 9, a rectangular key 10, and a magnetic fluid 11.

[0022] The housing 1 adopts a split-face mounting design. A bushing 2 is fixedly connected to the rotor on the side of the housing 1 closest to the atmosphere. A sealing ring 7 is installed between the bushing 2 and the rotor to ensure a seal at this location. A stationary ring 3 is connected to the inner surface of the bushing 2, and a spring 4 is provided between the stationary ring 3 and the inner left wall of the housing 1. Ferromagnetic pole shoes 9 and an electromagnetic coil 8 are installed between the housing 1 and the rotor on the side of the housing 1 closest to the equipment interior. A magnetic fluid seal 11 is provided between the ferromagnetic pole shoes 9 and the rotor. The magnetic fluid seal 11 utilizes an electromagnet to generate a strong magnetic field in the sealing gap between the rotor and the ferromagnetic pole shoes 9, attracting the magnetized sealant to the toothed end of the ferromagnetic pole shoes 9, where the magnetic field strength is highest. A toothed seal 5 is installed between the housing 1 and the rotor in the middle. The toothed seal 5 is fixed to the inner side of the housing 1 by a spring plate 6.

[0023] Preferably, the bushing 2 is fixed to the rotor by a rectangular key 10. Preferably, the distance between the tooth tip of the toothed seal 5 and the rotor is less than the distance between the ferromagnetic pole shoe 9 and the rotor.

[0024] Preferably, the end face of the bushing 2 is machined with a dynamic pressure groove, and the bushing 2 (moving block) and the stationary ring 3 are ground and polished.

[0025] Preferably, a sealing ring 7 is installed between the ferromagnetic pole shoe 9 and the housing 1 to ensure a seal at that location.

[0026] In use, first install the stationary ring 3, spring 4, toothed seal 5, and magnetic fluid sealing structure onto the upper and lower housings respectively and add magnetic fluid. Then install the bushing 2 onto the rotor, install the rotor onto the lower housing, and close the upper housing to complete the installation.

Claims

1. A combined sealing structure, characterized in that: The device includes a housing, a bushing, a stationary ring, a spring, a toothed seal, a spring plate, an electromagnetic coil, a ferromagnetic pole shoe, and a magnetic fluid. The bushing is fixedly connected to the rotor on the side of the housing closest to the atmosphere. A stationary ring is connected to the inner side of the bushing, and a spring is provided between the stationary ring and the left inner wall of the housing. Ferromagnetic pole shoes and an electromagnetic coil are installed between the housing and the rotor on the side of the housing closest to the interior of the device, and a magnetic fluid seal is provided between the ferromagnetic pole shoes and the rotor. A toothed seal is installed between the housing and the rotor in the middle, and the toothed seal is fixed to the inner side of the housing by a spring plate.

2. The combined sealing structure according to claim 1, characterized in that: The housing adopts a split-face mounting structure.

3. The combined sealing structure according to claim 1, characterized in that: The bushing is fixed to the rotor by a rectangular key.

4. The combined sealing structure according to claim 1, characterized in that: A sealing ring is installed between the bushing and the rotor to ensure a seal at that location.

5. The combined sealing structure according to claim 1, characterized in that: The end face of the bushing is machined with a dynamic pressure groove, and the bushing and the stationary ring are formed with a sliding seal through grinding and polishing.

6. The combined sealing structure according to claim 1, characterized in that: The distance between the tooth tips of the toothed seal and the rotor is less than the distance between the ferromagnetic pole shoe and the rotor.

7. The combined sealing structure according to claim 1, characterized in that: A sealing ring is installed between the ferromagnetic pole shoe and the housing to ensure a seal at that location.

8. The combined sealing structure according to claim 1, characterized in that: Magnetohydrodynamic (MHD) seals utilize an electromagnet to generate a strong magnetic field in the sealing gap between the rotor and the ferromagnetic pole shoe, attracting the magnetized sealant to the ferromagnetic pole shoe teeth where the magnetic field strength is highest.

9. The combined sealing structure according to claim 1, characterized in that: When the rotor rotates, the bushing rotates with the rotor, and an air film is formed between the bushing and the stationary ring, compressing the spring. When the rotor comes to a stop, the air film disappears, and the bushing and the stationary ring are tightly connected, ensuring a seal in the stationary state.

10. The combined sealing structure according to claim 1, characterized in that: When the rotor radial movement is large, the toothed seal first contacts the rotor, the rotor pushes the toothed seal inward, and then the rotor returns to its original position under the force of the spring plate, ensuring that the ferromagnetic material does not collide with the rotor.

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