The inner casing of one extraction back pressure steam turbine is a cylindrical structure

the dummy piston and the nozzle chamber combine into one entity

without central separating interface

the inner surface of said inner casing to be smooth

without steam seal gland.During the time of debugging

troubles of vibration excited by steam flow in the unit had occurred.Cause analysis has been carried out from two aspects of installation and design

and corresponding measures for eliminating said vibration being put forward.After implementation of the measures for eliminating vibration

the results of vibration and thermal performance show that the unit has basically reached the requirements of design.