Construction process of steam turbine low-pressure cylinder inner shaft seal steam supply and return pipeline thermal insulation device

Abstract

The invention discloses a construction process of a steam turbine low-pressure cylinder inner shaft seal steam supply and return pipeline thermal insulation device. The process comprises the followingsteps that (S1) a steam turbine low-pressure cylinder shaft seal steam supply and return pipeline is mounted according a drawing; (S2) a plurality of supporting pieces are mounted on the pipeline ateven intervals, and a first temperature sensor and a temperature control device are installed at the same time; (S3) thermal insulation plates of pieces are wrapped around the supporting pieces and are clamped by hoops; (S4) second temperature sensors and controllers are installed on the thermal insulation plates; and (S5) after mounting is completed, comprehensive inspection and acceptance are carried out to guarantee that mounting is accurate and foreign matters do not exit in a low pressure cylinder of a steam turbine is ensured. Through the scheme, the purpose of avoiding instability of atemperature of a unit vibration shaft seal is achieved, and high practical value and popularization value are achieved.

Description

technical field [0001] The invention belongs to the technical field of steam turbines, and in particular relates to a construction process of a heat preservation device for a shaft seal in a low-pressure cylinder of a steam turbine for supplying and returning steam. Background technique [0002] In the no-load stage of steam turbine startup, the blast exhaust temperature of the rear cylinder is often high, generally greater than 80°C. This will cause the overall expansion difference of the steam turbine to exceed the limit. For this reason, a water spray cooling device for the rear cylinder is installed between the low-pressure cylinder after the last blade of the steam turbine and the condenser to adjust the exhaust temperature of the rear cylinder to ensure that the overall expansion difference of the steam turbine does not exceed the limit. [0003] In order to prevent air from leaking in at the shaft end of the low-pressure cylinder of the steam turbine, the shaft end s...

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Problems solved by technology

[0006] The purpose of the present invention is to provide the construction technology of the heat preservation device for the shaft seal supply and return pipeline in the low-pressure cylinder of the steam turbine, mainly to solve the problem in the prior art that the temperature of the shaft seal supply and return pipeline of the low-pressure cylinder is lowered by water spraying, which may cause pipeline damage. The temperature fluctuates, which causes the temperature instability of the vibration shaft seal of the unit

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