Combined fluid dynamic pressure type rear isolation sealing device for turbomachinery dry gas seal

Abstract

The invention relates to a combined fluid dynamic pressure type rear isolation sealing device for turbomachinery dry gas seal. The combined fluid dynamic pressure type rear isolation sealing device isarranged between a dry gas seal assembly and a bearing box, and includes a carbon ring sealing unit and a fluid dynamic pressure type sealing unit, wherein the carbon ring sealing unit is arranged between the dry gas seal assembly and the fluid dynamic pressure type sealing unit, the fluid dynamic pressure type sealing unit includes a rotating assembly and a motionless assembly, the rotating assembly sleeves the outside of a main shaft and rotates at a high speed with the main shaft, the motionless assembly is arranged around the main shaft and fixed to the shell, one end surface of the rotating assembly and one end surface of the motionless assembly are attached to form a sealing surface, the sealing surface is perpendicular to the axial direction of the main shaft, and a fluid dynamic pressure groove is formed in the end surface of the rotating assembly. Compared with the prior art, the combined fluid dynamic pressure type rear isolation sealing device can realize zero leakage of lubricating oil on the bearing side to the dry gas seal when applied to turbomachinery, and the loss of isolation gas is small.

Description

technical field [0001] The invention relates to the technical field of mechanical seals, in particular to a combined fluid dynamic pressure rear isolation seal device for dry gas seals of turbomachinery. Background technique [0002] Turbomachinery includes turbocompressors (such as centrifugal compressors, axial flow compressors) and turboexpanders, which are high-speed rotating equipment and are also the core key equipment of petroleum, chemical and other equipment. At present, dry gas seals are commonly used in turbomachinery, that is, dry-running, gas-lubricated, non-contact mechanical seals, as their shaft end seals. Whether it is a single-end dry gas seal, double-end dry gas seal, tandem dry gas seal, or tandem dry gas seal with a middle labyrinth, it is necessary to use a rear isolation seal to isolate the dry gas seal from the bearing box to prevent the bearing box from Lubricating oil produced by the high-speed rotation of the main shaft pollutes the outer seal of ...

AI Technical Summary

Problems solved by technology

Sometimes the carbon and graphite powder worn down during the running-in period may cause the failure of the outer seal of the dry gas seal

[0004] The static leakage of the non-contact carbon ring seal is too large, and the consumption of the isolation gas is very sensitive to the temperature of the carbon ring seal

For some special working conditions, such as the axial distance between the bearing and the dry gas seal is too close; the position of the oil discharge port of the bearing is unreasonably designed; the oil inlet pressure of the bearing is too high; the oil return port of the bearing box is too small, and the oil return flow is not smooth, etc. Both the labyrinth seal and the carbon ring seal may have a short circuit of the isolated gas, causing the bearing lubricating oil or lubricating oil gas to enter the outer seal of the dry gas seal, pollute the dry gas seal, and cause the dry gas seal to fail

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