Download - Gland Sealing System Complete
-
8/16/2019 Gland Sealing System Complete
1/46
NTRODUCT ON TO
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
2/46
SEAL STEAM SYSTEM
Glands are used on turbine to prevent or reduce leakageof steam or air between rotating and stationary
components, which have a pressure difference across
them; this applies particularly where the turbine shaftpasses through the cylinder. If the cylinder pressure is
higher than atmospheric pressure, there will be a general
steam leakage outwards. If the cylinder is below
atmospheric pressure there will be a leakage of air
inwards, and some sort of sealing system must be used to
prevent air from entering the cylinder and the condenser.
-
8/16/2019 Gland Sealing System Complete
3/46
SEAL STEAM SYSTEM
500M turbine has got ! sets of gland seals. "ne for
each side of #$, I$ and %$. &ach set has got number of
sectionali'ed gland. &ach segment is supported by two
flat spring sections.
-
8/16/2019 Gland Sealing System Complete
4/46
HP, IP AND LP TURBINE
-
8/16/2019 Gland Sealing System Complete
5/46
HP, IP AND LP TURBINE
-
8/16/2019 Gland Sealing System Complete
6/46
HP TURBINE
-
8/16/2019 Gland Sealing System Complete
7/46IP TURBINE
-
8/16/2019 Gland Sealing System Complete
8/46LP TURBINE
-
8/16/2019 Gland Sealing System Complete
9/46TURBINE SYSTEM
-
8/16/2019 Gland Sealing System Complete
10/46
(he penultimate section of each gland is supplied with
steam from gland steam header, which is maintained
at a pressure of ).0*kg+s cm to ).05 kg+s cm and
temperature between )*0 deg - to )50 deg - in a )0
M / 1esign (urbine. (he last section of each
gland goes to Gland 2team -ondenser which remains
at vacuum.
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
11/46
3umber of sections in each turbine front and rear glands4
#$ front 4 * sections
#$ rear 4 sections
I$ front 4 sections
I$ rear 4 sections
%$ front 4 sections
%$ rear 4 sections
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
12/46
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
13/46
SEAL STEAM SYSTEM
ROTOR
CASING
RADIAL CLEARANCE
RADIAL CLEARANCE
AXIAL
CLEARANCE
STEAMFLOW
RADIAL CLEARANCE = 0.4 & 0.5 MM
-
8/16/2019 Gland Sealing System Complete
14/46
SEAL STEAM SYSTEM
STEAM THROTTLINGWhe !"e#$ %#!!e! "h'()h "he #*+# -e##-e!
e"/ee "he !e# +! ' "he -#!+) #* '"' #
"he$'*1#$+- %'-e!! 2'/ #! "h'""+) "#2e!%#-e. A! # e!(" ' %#!!+) "h'()h # !$#
#%e"(e ' + -e##-e "he !"e#$ "e* "' ''!e +"!
%e!!(e #* )#+ 3e'-+"1. Th(! "he e"h#%1 '"he !"e#$ e'e #* #"e e$#+! -'!"#".
The e*(-e* %e!!(e !"e#$ +! -'e-"e* "' #
'/e %e!!(e he#*e + !"e%!.
-
8/16/2019 Gland Sealing System Complete
15/46
GLAND STEAM HEADER
GLAND STEAM CONDENSER
IP EXHAUST
CRH
HPT IPT LPT
SEAL STEAM SYSTEM
GLAND STEAM HEADER TEMPERATURE 60 0CGLAND STEAM HEADER PRESSURE 750 $$/-
-
8/16/2019 Gland Sealing System Complete
16/46
SEAL STEAM SYSTEM
DESUPERHEATER
S
S
S
6rom M2 %ine
$ressure -ontroller
2pray from 76$ discharge
8u9iliary 2team from
Interconnecting nit
8:I%I8< $12 #&81&
6or 1+8
$egging6or
8tomi'ing
(o
2-8$#
6or (urbine
Gland
2ealing
(o 6uel
"il #eating
( o I n t e r c o n n e c t i n g
0 n i t
HPT IPT LPT
(o -ondenser
%eak off -ontroller
Gland
2team
-ontroller
(o
6lash(ank
"rifice
(o
6lash
(ank
S
GSC
(o 8tmosphere
S
S
6rom -# %ine
-
8/16/2019 Gland Sealing System Complete
17/46
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
18/46
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
19/46
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
20/46
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
21/46
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
22/46
ROTOR FINS
SEALSEGMENTS
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
23/46
L#1+"h Se#6or labyrinth packing a relatively soft
metallic material is used. (he
packing is segmented and
assembled concentric to the turbine
shaft and held in place by multiple
coil springs. 8 #1+"h seal is aMechanical 2eal that fits around an
a9le to prevent the leakage of oil or
other fluids.
SEAL STEAM SYSTEM
-
8/16/2019 Gland Sealing System Complete
24/46
8 labyrinth seal is composed of many straight groovesthat press tightly inside another a9le, so that the fluid
has to pass through a long and difficult path to escape.
6or labyrinth seals on a rotating shaft, a very small
clearance must e9ist between the tips of the labyrinth
threads and the running surface.
%abyrinth seals on rotating shafts provide non=contact
sealing action by controlling the passage of fluid through
a variety of chambers by centrifugal motion, as well as
by the formation of controlled fluid vortices.
LABYRINTH SEAL
-
8/16/2019 Gland Sealing System Complete
25/46
8t higher speeds, centrifugal motion forces the liuidtowards the outside and therefore away from any
passages. (he labyrinth seals are non=contact type,
therefore the wearing out rate is much slower.
(urbines use labyrinth seals due to the lack of friction,
which is necessary for high rotational speeds.
LABYRINTH SEAL
-
8/16/2019 Gland Sealing System Complete
26/46
> 2urface type.
> #ori'ontally pipe mounted cooler.
> single pass heat e9changer.
GLAND STEAM CONDENSER
3umbers 4) 9 )00?3umber of tubes 4@AA(ube si'e Bmm 9 mmC 4)!.0 9 0.DDA"verall length of shell BmC 4).2hell outer diameter BmmC 4@!0
2hell thickness BmmC 45.0-ondensate 6low, 4))**@*.0 kg+hr -ondensate Inlet (emp, () 4!.! deg -
-ondensate "utlet (emp, ( [email protected] deg -
#eat (ransfer 8rea provided, 8a
4).! m
-
8/16/2019 Gland Sealing System Complete
27/46
M8(&I8%4
(7&24 &%1&1 22*0
+7":, 2#&%% E (7& $%8(&24 7.F. 2(&&%
GLAND STEAM CONDENSER
-
8/16/2019 Gland Sealing System Complete
28/46
SEAL STEAM PIPING WITHOUT DEC8
HPT IPTLPT
CROSS AROUNG PIPE
-
8/16/2019 Gland Sealing System Complete
29/46
PROBLEMS ASSOCIATED WITHABNORMAL SEAL STEAM PARAMETERS
> DAMAGE TO GLAND SEGMENTS
> BARRING GEAR 9AMMING
> DISTORTION IN TURBINE CASING : ROTOR> STEAM LEA8AGE
> POOR ;ACUUM
-
8/16/2019 Gland Sealing System Complete
30/46
OTHER SEAL TYPES
-
8/16/2019 Gland Sealing System Complete
31/46
Fe" Se#!
6elt seals are mainly used as oil or grease seals for
retaining lubrication and at the same time preventing
dirt or dust entering the bearing.6elt has long been used for sealing duties because of
numerous favourable properties such as wicking and
oil absorption properties, fine filtering and resilience.(his allows the felt to maintain a constant sealing
pressure and as the seal wears the felt surface
remains unchanged.
OTHER SEAL TYPES
-
8/16/2019 Gland Sealing System Complete
32/46
Fe" Se#!
6elt seals are usually pre=saturated with lubricants of a
higher viscosity than the bearings offering positive
bearing protection. If the seal does run dry it will tendto protect and polish the shaft rather than cause
damage. (hrough normal operating temperatures
and conditions the felt seal is highly economical,normally reuiring replacement when the machine is
overhauled.
OTHER SEAL TYPES
-
8/16/2019 Gland Sealing System Complete
33/46
OTHER SEAL TYPES
Fe" Se#!hen the seal is correctly installed the seal is effective
over a variety of operating conditions and a wide
range of speeds. 3ormal ma9imum rubbing speed is)0 m+s but can be as high as 0m+s if the rubbing
surfaces are highly polished and lubricant is always
present.6elt 2eals are not suitable for oils with e9tremely low
viscosity or the lubricant is pressurised.
-
8/16/2019 Gland Sealing System Complete
34/46
OTHER SEAL TYPES
FELT SEALS
-
8/16/2019 Gland Sealing System Complete
35/46
L+% Se#!
(his is an assembly consisting of a rubbing elastomer
ring seal element held in place by spring. (he seal
friction is reduced as an oil film is generated between
the lip of the seal and the shaft. 8ny damage to the
shaft where the seal runs will cause leakage because
the optimum oil film thickness will be e9ceeded locally.
(herefore the shaft finish is especially important, as
leakage will occur if an irregular surface is present.
OTHER SEAL TYPES
-
8/16/2019 Gland Sealing System Complete
36/46
L+% Se#!
(he lubricated rubbing provides the sealing action.
(his sealing action cannot be maintained at high
speeds if the shaft is not running perfectly true. (o
maintain oil film thickness the seal must follow any
shaft movement. (his becomes difficult when the shaft
is subect to eccentric running or vibration at high
speeds. (ypically these seals will operate in the region
of )D m+s and the seals are affected by friction.
OTHER SEAL TYPES
-
8/16/2019 Gland Sealing System Complete
37/46
OTHER SEAL TYPES
LIP SEALS
-
8/16/2019 Gland Sealing System Complete
38/46
Fe'(+* Se#!
(his is a very specialised rotary seal type which has
superior theoretical benefits.
(he seal is a fluid ring which is retained in placebetween the rotating and fi9ed members under the
action of magnetic forces.
6errofluidic sealing technology takes advantage of theresponse of a fluid, containing a uniform distribution of
magnetic particles, to an applied magnetic field.
OTHER SEAL TYPES
-
8/16/2019 Gland Sealing System Complete
39/46
Fe'(+* Se#!
It uses a magnet with magnetically permeable north
and south pole pieces and a magnetically permeable
shaft to create a permanent magnetic circuit. (hemagnetic flu9 is concentrated in the gap under each
pole and when ferrofluid is applied to this gap it
assumes the shape of a liuid o=ring and produces ahermetic seal.
OTHER SEAL TYPES
-
8/16/2019 Gland Sealing System Complete
40/46
Fe'(+* Se#!
6errofluidic seals offer provide hermetic sealing, long life,
virtually frictionless sealing and smooth operation. (hey
are non=contaminating, highly reliable and can operate at
high speeds. (his type of seal can be used over a wide
temperature range, which can be increased by use of
cooling, or heating circuits. (he seals have to be regularly
maintained as the fluid properties deteriorate over time.
(hese bearings are used for very specialised applications
OTHER SEAL TYPES
-
8/16/2019 Gland Sealing System Complete
41/46
OTHER SEAL TYPES
FERROFLUID SEALS
-
8/16/2019 Gland Sealing System Complete
42/46
> 1ensely packed bristle pack welded to the front andback plates that provide mechanical support for
sealed pressure.
BRUSH SEALS
-
8/16/2019 Gland Sealing System Complete
43/46
> 1uring rotor growth and e9cursions, bristle pack deflects
elastically and springs back to new positions to maintain
sealing contactH without little or no permanent damage.
> -urrent labyrinth seal will be permanently damaged
during a rotor contact
BRUSH SEALS
-
8/16/2019 Gland Sealing System Complete
44/46
LABYRINTH SEAL ;IS
-
8/16/2019 Gland Sealing System Complete
45/46
educed leakage and parasitic loss compared
to current labyrinth seals, resulting from4
> Its ability to significantly reduce as=installed seal
clearance
> Its ability to withstand rotor growth and e9cursionswithout enlarging seal clearance
LABYRINTH SEAL ;IS
-
8/16/2019 Gland Sealing System Complete
46/46
> %arge impact on efficiency gain with a relatively low
investment. -ost of energy savings is orders of
magnitude higher than incremental cost of seal
LABYRINTH SEAL ;IS