The components/parts in the steam path of an aging steam turbine long operational hours are usually the most deteriorated. However, it is difficult to find out all deteriorated/damaged components/parts at the general periodical inspection. Therefore, Toshiba has developed Precise Inspection Program.
The scope of Precise Inspection is as follows;
The following Tables give an overview Precise Inspections.
Abbreviation for the following Tables
NDT: Non-destructive Test
VT: Visual Test
PT: Dye Penetrating Test
MT: Magnetic Particle Test
UT: Ultrasonic Test
DM: Dimension Check
HP CASING
CASING
| Inspection |
Evaluation |
NDT (VT, PT, MT, UT)
Life Assessment
DM of Female Thread / Horizontal Flange |
Wall Thickness
Remaining Life
|
BOLTS
| Inspection |
Evaluation |
| NDT (VT, PT, UT), HT |
Damage to Thread
Hardness |
SEAL RINGS
| Inspection |
Evaluation |
| NDT (VT, PT), DM |
Clearance |
LP CASING
| Inspection |
Evaluation |
| NDT (VT, PT) for Welded Part |
|
BEARINGS
JOURNAL BEARINGS
| Inspection |
Evaluation |
NDT (VT, PT, UT) of White Metal
DM of Inner Diameter |
Clearance |
THRUST BEARINGS
| Inspection |
Evaluation |
NDT (VT, PT, UT) of White Metal
DM of Taper Thrust Plate |
Clearance |
NOZZLES DIAPHRAGM
| Inspection |
Evaluation |
NDT (VT, PT, MT)
DM of Nozzle Throat |
Nozzle Area |
TURNING DEVICE
| Inspection |
Evaluation |
NDT (VT)
DM |
Backlash |
ROTOR
ROTOR
| Inspection |
Evaluation |
NDT (PT, MT) of Wheel Fillet
NDT (VT, MT) of Journal / Labyrinth
Run-out Check
Life Assessment (for HP, IP Rotor) |
Bowing
Remaining Life |
COUPLING
| Inspection |
Evaluation |
NDT (VT, PT) of Thread
DM of Reamer Bolts |
Clearance |
BLADES
BLADES
| Inspection |
Evaluation |
NDT (VT, PT, MT, UT)
DM of Dovetail Clearance
DM of Tenon
Life Assessment (for HP, IP stages) |
Lifting
Erosion
Remaining Life |
SHROUND BANDS
| Inspection |
Evaluation |
NDT (VT, PT, MT)
DM of Clearance |
Lifting |
EROSION SHIELDS
| Inspection |
Evaluation |
NDT (PT)
DM |
Erosion |
For Precise Inspection, Toshiba has also developed its own specific systems. The following are a part of these inspection systems.
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