05-12-2012, 04:09 PM
STEAM TURBINE Presentation Transcript
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1. Presentation Outline
Theory of Turbine
Turbine casing
Rotor & Blades
Sealing system & barring gear
ESV’s, IV’s and CV’s
Coupling and Bearing
2. Steam Turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into useful mechanical work.
3. Impulse Turbines
An impulse turbine uses the impact force of the steam jet on the blades to turn the shaft. Steam expands as it passes through the nozzles, where its pressure drops and its velocity increases. As the steam flows through the moving blades, its pressure remains the same, but its velocity decreases. The steam does not expand as it flows through the moving blades.
4. Reaction Turbines
In the reaction turbine, the rotor blades themselves are arranged to form convergent nozzles. This type of turbine makes use of the reaction force produced as the steam accelerates through the nozzles formed by the rotor.
5. TURBINE COMPONENTS
CASING
ROTOR
BLADES
SEALING SYSTEM
STOP & CONTROL VALVES
COUPLINGS & BEARINGS
BARRING GEAR
6. Turbine Casings
HP Turbine Casing
outer casing: a barrel-type without axial or radial flange.
Barrel-type casing suitable for quick startup and loading.
The inner casing--- cylindrical , axially split.
The inner casing is attached in the horizontal and vertical planes in the barrel casing so that it can freely expand radially in all directions and axially from a fixed point (HP-inlet side).
7. IP Turbine Casing
The casing of the IP turbine is split horizontally and is of double-shell construction.
Both are axially split and A double flow inner casing is supported in the outer casing and carries the guide blades.
Provides opposed double flow in the two blade sections and compensates axial thrust.
Steam after reheating enters the inner casing from Top & Bottom.
8. LP Turbine Casing
The LP turbine casing consists of a double flow unit and has a triple shell welded casing.
The shells are axially split and of rigid welded construction.
The inner shell taking the first rows of guide blades, is attached kinematically in the middle shell.
Independent of the outer shell, the middle shell, is supported at four points on longitudinal beams.
Steam admitted to the LP turbine from the IP turbine flows into the inner casing from both sides.