Customized High Temperature Resistant Steam Turbine Bushing with Precision Guiding for HP Main Stop Valve

During the maintenance and operation of the steam turbine high-pressure main stop valve, the valve stem bushing is a critical precision component that is easily overlooked yet vitally important. Operating continuously under harsh conditions of high temperature, high pressure and frequent opening/closing cycles, the bushing's guiding accuracy and sealing performance directly determine the operational stability of the valve stem, the tightness of valve sealing and the safety of the unit. It serves as an essential basic part to ensure reliable operation of the high-pressure main stop valve.

The high-pressure main stop valve bushing performs two core functions:

• Precise Guiding: Restricts the movement path of the valve stem to ensure accurate centering of the valve stem and valve disc, preventing deflection, shaking, jamming and abnormal wear during opening and closing operations
• Auxiliary Leakage Control: The precision fit clearance between the bushing and valve stem effectively controls stem steam leakage, with excess leaked steam delivered to the deaerator and gland steam condenser via dedicated pipelines

The precision of the bushing fit clearance is a key control indicator in maintenance work:

• Excessive Clearance: Aggravates valve stem shaking and leads to guiding failure, resulting in poor contact between valve disc and valve seat with sharp rise in stem steam leakage
• Insufficient Clearance: Increases friction resistance of the valve stem, causing valve jamming and opening/closing delay, potentially compromising unit emergency shutdown reliability

Additional defects such as inner wall wear, surface scoring and deformation of the bushing will undermine valve operating stability and shorten equipment service life.