Self-centering sealing piece for achieving floating through gas pressure difference action and mounting method of self-centering sealing piece

Abstract

A self-centering sealing piece for achieving floating through gas pressure difference action comprises a main sealing ring, circumferential spacers, a friction reducing ball and a ball retaining ring. The main sealing ring is of a labyrinth seal structure and is provided with at least two sealing teeth, sealing clearances formed between the sealing teeth and a rotor are not completely equal, and the low-pressure side sealing clearances are not larger than the high-pressure side sealing clearances. A labyrinth sealing cavity is divided into a plurality of tooth cavities through the circumferential spacers, so that the labyrinth sealing cavity is of a bag type structure. The ball retaining ring is matched with the main sealing ring. The main sealing ring is circumferentially provided with a plurality of radial slots, and the circumferential spacers are inserted into the radial slots in the radial direction. In the mounting process, it is guaranteed that the clearance between the attaching faces of a sealing cover and a sealing seat is as small as possible, and an auxiliary sealing ring is arranged between the matching faces of the sealing cover and a sealing piece body. The inner side of the auxiliary sealing ring is communicated with the high-pressure side, and the outer side of the auxiliary sealing ring is communicated with the low-pressure side. A rotating preventing pin is arranged between the sealing piece body and the sealing seat or the sealing cover. According to the self-centering sealing piece for achieving floating through gas pressure difference action, the advantages of traditional labyrinth sealing and floating sealing are integrated, and the defects of traditional labyrinth sealing and floating sealing are abandoned.

Description

technical field [0001] The invention relates to a self-concentric sealing member which realizes floating by the effect of gas pressure difference and an installation method thereof, belonging to the field of rotary mechanical seals. Background technique [0002] Labyrinth seals are not limited by rotation speed, temperature and pressure difference, so they are widely used in turbo equipment such as compressors, steam turbines, gas turbines, and aeroengines. However, the labyrinth seal also has its own defects that are difficult to overcome. Generally, it is necessary to reserve a large enough gap to avoid possible friction due to rotor eccentricity and over-critical speed; even so, the labyrinth seal is often damaged due to transient friction. resulting in a permanent widening of the gap. [0003] The traditional floating seal mainly relies on the buoyancy of the liquid film formed by the high-speed rotation of the rotor to maintain a non-contact state with the rotor, and c...

AI Technical Summary

Problems solved by technology

However, when sealing gas, the floating seal should be filled with lubricating oil (such as the sealing shoe used to seal hydrogen at the end of the generator shaft) to facilitate sealing and lubrication, so an additional oil circuit system is required

[0004] The main application limitation of the traditional floating seal is that it is generally not suitable for the sealing of high-temperature gas; in some special occasions, although the selection of special materials (such as graphite) allows direct contact with the rotor without auxiliary sealing oil, there are also relatively strict Strict applicable line speed and temperature limitations

Due to the low viscosity of the gas, extremely high rotational speed or line speed is required to form a dynamic pressure gas film. Therefore, even if it is applied to the sealing of high-temperature gas, the floating seal and the surface of the rotor are generally in a state of dry friction, which is not conducive to its long-term stable sealing performance.

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