gland sealing system complete

8/16/2019 Gland Sealing System Complete

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NTRODUCT ON TO

SEAL STEAM SYSTEM


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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.


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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.


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HP, IP AND LP TURBINE


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HP, IP AND LP TURBINE


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HP TURBINE


7/46IP TURBINE


8/46LP TURBINE


9/46TURBINE SYSTEM


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(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


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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


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SEAL STEAM SYSTEM


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SEAL STEAM SYSTEM

ROTOR

CASING

RADIAL CLEARANCE

RADIAL CLEARANCE

AXIAL

CLEARANCE

STEAMFLOW

RADIAL CLEARANCE = 0.4 & 0.5 MM


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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%!.


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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 $$/-


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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


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SEAL STEAM SYSTEM


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SEAL STEAM SYSTEM


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SEAL STEAM SYSTEM


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SEAL STEAM SYSTEM


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SEAL STEAM SYSTEM


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ROTOR FINS

SEALSEGMENTS

SEAL STEAM SYSTEM


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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


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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


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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


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> 2urface type.

> #ori'ontally pipe mounted cooler.

> single pass heat e9changer.


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


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M8(&I8%4

(7&24 &%1&1 22*0

+7":, 2#&%% E (7& $%8(&24 7.F. 2(&&%



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SEAL STEAM PIPING WITHOUT DEC8

HPT IPTLPT

CROSS AROUNG PIPE


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PROBLEMS ASSOCIATED WITHABNORMAL SEAL STEAM PARAMETERS

> DAMAGE TO GLAND SEGMENTS

> BARRING GEAR 9AMMING

> DISTORTION IN TURBINE CASING : ROTOR> STEAM LEA8AGE

> POOR ;ACUUM


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OTHER SEAL TYPES


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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


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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


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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.


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OTHER SEAL TYPES

FELT SEALS


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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


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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


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OTHER SEAL TYPES

LIP SEALS


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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


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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


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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


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OTHER SEAL TYPES

FERROFLUID SEALS


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> 1ensely packed bristle pack welded to the front andback plates that provide mechanical support for

sealed pressure.

BRUSH SEALS


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> 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


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LABYRINTH SEAL ;IS


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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


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> %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

gland sealing system complete

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