gland sealing system
TRANSCRIPT
-
8/10/2019 Gland Sealing System
1/4
Gland sealing system
KWU 210MW turbine generator
Turbine and auxiliaries
Aron Ghosh
Roll no. 03515303711
5 th semester (electrical)
-
8/10/2019 Gland Sealing System
2/4
Gland sealing system
Glands are used on turbine to minimise the leakage of steam (or air) between the rotatingand stationary parts components which have a pressure difference across them.
LOCATION: particularly where turbine shaft passes through the cylinder. In both the cases :
1. PRESSUREcylinder > PRESSUREatmosphere (general steam leakage outwards)
2. PRESSUREcylinder < PRESSUREatmosphere (general steam leakage outwards)
-sealing system is employed to prevent air from entering into cylinder and condenser.
Steam turbine losses (effusion of steam) in 210 MW KWU turbine:
Causes:
Change in internal condition of turbine:Mechanical damagesFlow area decreasesFlow area bypassFlow area increases
Change in inlet conditions
Symptoms:
Sudden change in section efficiency Sudden change in section pressure ratio Increased downstream extraction temperature
-
8/10/2019 Gland Sealing System
3/4
-
8/10/2019 Gland Sealing System
4/4
TURBINE GLAND SEALING IN 210MW KWU TURBINE : Turbine shaft glands are sealed with auxiliary steam supplied by an electro-hydraulically controlled
seal steam pressure control valve. A pressure of 0.01 Kg/cm 2 (g) is maintained in the seals. Above a load of 80 MW the turbine become self-sealing.
The leak off steam from HPT/IPT glands is used for sealing LPT glands. The steampressure in the header is then maintained constant by means of a leak-off control valve, which isalso controlled by the same electro-hydraulic controller, controlling sealsteam pressure control valve.
The last stage leak-off of all shaft seals is sent to thegland steam cooler for regenerative feed heating.Refer the Figure.
Steam Turbine running without Gland Condenser :
The steam escaping from seals can migrate and condense in the bearing lube oil system causingdegradation of the lube oil properties.Pollution from the release of toxic vapors containing additives from the machine is also evident.
Steam Turbine running with Gland Seal System :
In the configuration which employs gland sealing system (use ofa steam ejector or an electric motor fane), the watermigration to the lube oil system is eliminated and contamination of the lubeoil by steam leakage is avoided.