08. detlef - alignment&dummy cairo
TRANSCRIPT
1Cairo, May 2009
Steam Turbine Alignment
©Si
emen
s Po
wer
Gen
erat
ion
2003
. All
Rig
hts
Res
erve
d
May 2009
2
Alignment POWER GENERATION
Introduction
Subject:
Steam Turbine Alignment
Main parts:●
General
●
Steam turbine inner alignment
●
Shaft alignment
●
Modified front end bearing housing
May 2009
3
Alignment POWER GENERATION
General
May 2009
4
Alignment POWER GENERATION
Internal
/ external
alignment
Internal
alignment:
Ensure
sufficient
internal
clearance
(vertical
/ horizontal)
between
rotor
and stationary
parts
under
consideration
ofCasing deflectionRotor bending lineRotor lifting (approx. 1/3 of bearing Thermal growth clearance)
External
shaft
alignment:Positioning of the rotational centers of the two shafts such that they are co-linear under operating conditions. Reduce dynamic shaft forcesKeep bearing loading normalEnsure thrust bearing parallelity to thrust discEnsure free movement ( sample shoulder bolts horizontal/vertical )Ensure stress free pipe connectionEnsure all fix points are reamed and tight inserted
May 2009
5
Alignment POWER GENERATION
Turbine inner alignment
May 2009
6
Alignment POWER GENERATION
Internal
clearance
Shrouded rotor blade
Stator blade Radial rotor blade clearance
Radial stator blade clearance
Axial blade clearance
Stator
Rotor
May 2009
7
Alignment POWER GENERATION
Rubbing damage
Unilateral radial gaps
Major alignment deviations
Foundation changes
More than >=2 Guide Blade Carriers installed
Inclination of front bearing housing
Measurement with Alignment shaft
is recommended when ;
May 2009
8
Alignment POWER GENERATION
Reason of trust disc damage
High cyclic loading of the disc, which probably caused by
inclination or tilting of the front bearing housing towards the shaft center line
=> In this case a high bending force and moment is acting on the disc
Inclination or tilting of the front bearing housing arise by :
misalignment
high friction underneath the turbine casing paws
hot spot at the foundation between turbine and base frame or bearing pedestal
steam radiation out from the front gland
distension / sliding disability
acting forces and moments from the steam pipes
May 2009
9
Alignment POWER GENERATION
Alignment Deviations, samples
-
Setting of foundation
-
Inadmissible external forces (pipings/condenser)
-
Thermal deformations
-
Inadequate sliding behavior of front bearing pedestal
May 2009
10
Alignment POWER GENERATION
Internal
Alignment considerations
Static
rotor
deflection
line
Kinetic
rotor
deflection
line
GBC 2GBC 1
GBC 3 GBC 4 + 5
Bearing centre
line
Lower
vertical
position
of GBC 1 + 2
May 2009
11
Alignment POWER GENERATION
Alignment
shaft
1.
Pick-up
for
bearing
housing
end face and correct
2. Alignment
shaft
placed
in
turbine
lower
half , calibrate,
install top half , assemble turbine casing , tight , take records, disassemble and correct
Measurement
done
at closed
turbine
casing!
May 2009
12
Alignment POWER GENERATION
Alignment
shaft
arrangement
Alignment
shaft
supported
at the
front and rear
end bearing
housing.
Pick-up
for
front-end bearing
housing
end face
Weight
for
compensation
of shaft
deflection.Guide-blade carrier
Balance piston
labyrinth
Pick-up
for
rear-end
bearing
housing
end face.
Pick-ups
attached
to the
alignment
shaft
May 2009
13
Alignment POWER GENERATION
Casing
RotorSliding elements for vertical position
Bolts for horizontal position
Guide-blade carriers expand freely under the influence of heat without changing their symmetrical position
Guide-blade carrier
Centric guide-blade carrier suspension
Radial gap
May 2009
14
Alignment POWER GENERATION
Benefits
The correct adjustment of the radial gaps will minimize the danger of metal to metal contact
No unscheduled outages caused by rubbing
No unprofitable operation of the turbine due to radial gaps enlarged by rubbing
Permanent deformations of the turbine casing are detected and corrective actions can be initiated
No breaking out of babbit metal caused by bearing edge loading or Non-uniform loading
Smooth and best turning gear operation , especially when T.G. , where jacking oil is required to lift rotor
May 2009
15
Alignment POWER GENERATION
Shaft alignment
External Measurements
May 2009
16
Alignment POWER GENERATION
Fix Points
Ensure that ;
All Fix points are reamed and tightly inserted
May 2009
17
Alignment POWER GENERATION
Bumping Test
Radial clearance
May 2009
18
Alignment POWER GENERATION
Turboset arrangement
Front end bearing
Exhaust end bearing
DE bearing NDE bearing
NDE bea
Front end base plate
Front end base plate
Exhaust casing support Rigid coupling
Absolute
expansion
May 2009
19
Alignment POWER GENERATION
External
shaft
alignment
turbine
-
generator
GeneratorTurbine
Static
deflection
line
Kinetic
deflection
line Outboard bearing
to be
raised
by
3,6 mm
0,3 mm
Front and exhaust
end turbine
bearings
horizontalTurbine and Generator
flange parallel
May 2009
20
Alignment POWER GENERATION
Max. permissible
external
forces
and moments
May 2009
21
Alignment POWER GENERATION
External forces
Ensure stress free connections
May 2009
22
Alignment POWER GENERATION
Sample ;
-
shoulder bolts
(horizontal/vertical)
- improvement of sliding
behavior of importance,
if not already existing, than
to be modified accordingly
Ensure Free Expansion
May 2009
23
Alignment POWER GENERATION
Recommendation
Modified front end bearing housing
May 2009
24
Alignment POWER GENERATION
Sliding Plates required improvement
Sole plate with wear after 50.000 operation hours
Selflubricating
sliding plate beneath front bearing pedestal
The intention must be to keep the displacement forces exerted by the front end bearing pedestal on the sole plates and thus the coefficient of friction as small as possible. Only then uniform expansion and contraction of the bearing pedestal is possible, especially without any abrupt movements.
Old design
New design
May 2009
25
Alignment POWER GENERATION
Benefits
Small coefficients of friction during expansion and contraction of the turbine casings and thus reduction of load on the axial connecting and fixing elements and on the casing, bearing pedestal and foundation
Continues sliding of the bearing pedestal during start up and shutdown without any abrupt movement in terms of absolute and relative expansion
Prevention of tilting and or skewing of the bearing pedestal as a result of high friction related sliding forces and thus impermissible bearing loadings ( edge supports )
Ease of replacement of the sliding plates
Alignment / Inclination correction of pedestal , can also be done during minor overhaul, since height adjustment from outside
May 2009
26
Alignment POWER GENERATION
Thanksfor your attention
27Cairo, May 2009
Siemens AG, Power Generation
Industrial Application