Steam Turbine Valves Inspection Periodicity & Criteria
Steam Turbine Valves Inspection Periodicity & Criteria
(OP)
Hi guys just a quick question on the inspection of steam turbine valves.
Does anyone have advice on the inspection periodicity for steam turbine HP and IP stop and control valves?
The other question is with regards to life time. When should this valves be changed and under what criteria?
Even if the inspection results comes out as all in good condition should they be capped at certain running hours?
What components should be considered as critical? spindles? strainers? head? seats? etc
Does anyone have advice on the inspection periodicity for steam turbine HP and IP stop and control valves?
The other question is with regards to life time. When should this valves be changed and under what criteria?
Even if the inspection results comes out as all in good condition should they be capped at certain running hours?
What components should be considered as critical? spindles? strainers? head? seats? etc
Please do drop more information or knowledge you have on this subject they will all be taken in and appreciated.
David O.
Project Engineer





RE: Steam Turbine Valves Inspection Periodicity & Criteria
Please do drop more information or knowledge you have on this subject they will all be taken in and appreciated.
David O.
Project Engineer
RE: Steam Turbine Valves Inspection Periodicity & Criteria
if the inspection wear measurements and NDE guidlines are maintained, i would see no reason to replace. the inspections should include the removal of oxide buildup on the stems and bushings, ensuring that the harden surfaces are not damged in the process.
even with the inspections, valve operational testing should be performed to verify no stem binding and valve tightness is scceptable.
RE: Steam Turbine Valves Inspection Periodicity & Criteria
In Single Shaft Combined Cycle applications where the Gas Turbine + Steam Turbine + Generator are all in one shaft (very popular in Europe and Japan) the Steam Units have what is called a "Minor Inspection" that includes:
Bearings + Valves
Made to coincide with the Hot Gas Path inspection of the Gas Turbine (typically 24K)
The Major inspection of the Gas and Steam Turbines are also matched to minimize downtime
In Combined Cycle applications with no Simple Cycle capability the Waste Heat Boiler or Heat Recovery Steam Generator (HRSG) may dictate the inspection interval.
As a general rule of thumb, if no anomalies** are detected: the valves (and bearings) should be inspected once bewteen Major Inspections.
** anomalies: a typical one is the valves test taking longer than usual indicating that the valves are "binding"
saludos.
a.