Improved Brandon steam seal suitable for low-load working condition

Abstract

The invention relates to an improved Brandon steam seal suitable for a low-load working condition. The improved Brandon steam seal comprises cylindrical springs, steam seal bodies and a steam turbine rotor. The multiple steam seal bodies are distributed around the steam turbine rotor by a circle. The cross sections of the two sides of an arc section of each steam seal body are drilled, and the cylindrical springs are arranged in the drilled holes of the cross sections. The arc sections of the steam seal bodies are connected through the cylindrical springs, and the length of the springs is 65-75% of the conventional design length, wherein the conventional design length is 5-6 cm. The gap between the steam seal bodies and the steam turbine rotor in the closed state of the steam seal is 0.75+ / - 0.05 mm. The improved Brandon steam seal has the beneficial effects that the length of the steam seal springs is shortened, on one hand, the economical efficiency of a unit is improved, on the other hand, frequent opening and closing of the steam seal are avoided, the service life of the steam seal is prolonged, and the problems of steam leakage of the combination faces of steam seal sections, spring failures or jamming and the like caused by frequent scouring are prevented; and the design and installation gap of the gap bridge steam seal is increased so as to meet the requirement for long-term low-load operation, and the economical efficiency and safety of the unit are both considered.

Description

technical field [0001] The patent of the invention belongs to the technical field of energy steam turbine power generation, and relates to a steam seal of a coal-fired generating set suitable for participating in deep peak regulation and often operating under low load conditions (below 40%). Background technique [0002] Braden steam seals are currently widely used in steam turbine steam seals and shaft seals in thermal power plants. The principle is to mill out a steam induction groove on the steam inlet surface so that the pressure on the back side of the arc of the seal (the internal pressure of the seal body groove) is equal to the pressure on the side of the steam inlet. At the same time, drill holes on the end face of the arc section of the steam seal to install helical cylindrical springs. There are two spiral cylindrical springs in the middle of the upper and lower steam seal rings, totaling four. The thrust of the spring makes the seal arc open when there is no ste...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art, to provide a kind of improved Brayton steam seal suitable for low-load working conditions, and to solve the problem of low-load working conditions (below 40%) of steam turbines with high and medium pressure combined cylinder structures. , due to the economical decline caused by the incomplete closing of the bridge seal, the increase of the failure rate of the seal, etc.

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