Question 324Steam Plants - 1st Asst/Chief70% to pass
When turbine rotor shafts extend through the casing, an external source of sealing steam is used in conjunction with labyrinth packing to _______________.
AI Explanation
The correct answer is A) seal the casing during periods of low casing pressure.
When turbine rotor shafts extend through the casing, an external source of sealing steam is used in conjunction with labyrinth packing to maintain a positive pressure in the casing during periods when the internal casing pressure is low. This prevents air from being drawn into the casing, which could lead to oxidation and corrosion of the turbine components.
The other options are incorrect because: B) maintaining rotor journal temperature is not the primary purpose of the sealing steam, C) sealing during high casing pressure is not necessary, and D) providing a constant flow to the gland leak off condenser is not the main function of the sealing steam in this case.
Related Questions
#322 The labyrinth seals used on rotating steam turbine shafts reduces external leakage by causing _______________.#323 Where are moisture shields located in a main propulsion steam turbine? #325 Labyrinth seals used to reduce leakage around a turbine shaft are constructed of _______________.#326 Which of the devices listed is found on an LP main propulsion steam turbine casing? #327 The purpose of the sentinel valve installed on a turbine casing is to _______________.