Method for disassembling threaded ring of main steam valve

Abstract

The invention discloses a method for disassembling a threaded ring of a main steam valve. The method includes the steps of firstly, laying a heating device on the outer surface of a valve shell, and uniformly and circumferentially arranging a plurality of temperature measuring elements on the outer wall of the valve shell and under the heating device; secondly, placing refrigerating articles in an inner cavity of the threaded ring uniformly, and arranging a plurality of temperature measuring elements on the outer wall of the threaded ring uniformly; thirdly, assembling a special disassembling tool for the threaded ring at a disassembling port in the sidewall of the threaded ring, wherein a stress applying rod is fixed above the special disassembling tool, and the upper end of the stress applying rod is suspended on a lifting tool of a travelling crane; fourthly, when the measured temperature of the outer wall of the valve shell is 1-10 DEG C higher than that of the outer wall of the threaded ring, using a knocking device to strike the stress applying rod until the threaded ring is loose, and then using the special disassembling tool to disassemble the threaded ring. The method for disassembling the threaded ring of the main steam valve has the advantages that the cold shrinkage and thermal expansion theory is adopted to enable a valve body to expand and the threaded ring to shrink, disassembling quality is guaranteed, maintenance cost is reduced, and working efficiency is improved.

Description

technical field [0001] The invention relates to a high-temperature valve of a thermal power unit, in particular to a method for disassembling a threaded ring of a main steam valve in a high-temperature valve of a thermal power unit. Background technique [0002] In order to improve the energy utilization rate, the ultra-supercritical steam turbine has gradually become the main model in my country. The main steam combined valve of the ultra-supercritical steam turbine is the connecting device between the main steam pipeline and the steam turbine. It receives the high-temperature and high-pressure steam from the boiler and controls the unit. Power, stable turbine speed, and quick shutdown to protect the unit in an emergency are typical important high-temperature components. The main gas valve of the steam turbine is the first gate for the main steam to leave the boiler and enter the steam turbine. By adjusting the valve, the steam flow into the steam turbine can be changed, and...

AI Technical Summary

Problems solved by technology

[0003] In the process of overhauling the valve, the main steam valve needs to be disassembled. However, due to airtightness requirements, the pre-tightening force between the threaded ring and the inner wall of the valve casing is usually very large, and high temperature will cause the threaded ring to expand to increase the pre-tightening force. Removing the threaded ring is therefore laborious and time-consuming

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