Unit 17 - Chapter 69 Flashcards
The stationary passage of reaction turbines is the
Fixed blade and nozzles
A steam turbine’a exhaust can often supply a process with steam because
It is free of oil
The great majority of steam turbine governors utilize the
Mechanical centrifugal principle
The exhaust from a steam turbine is more acceptable for process than the exhaust from a steam engine because
It is free of oil
The exhaust steam from a condensing steam turbine ___ than the exhaust from a steam engine
Has more moisture
Turbines often have segmental carbon ring sealing glands which are held in place by
Garter springs
A steam turbine should trip or shit down when normal operating speed is exceeded by
10 - 15%
Condensing turbines
Will have a vacuum in the last row of rotating blades
Which turbine uses a condenser?
A turbine exhausting to a vacuum
The shrouding installed on the blading of a steam turbine serves to
Confine steam to the blades
A turbine over speed trip
- prevents the turbine exceeding maximum rated speed
- will close the steam stop valve
- should be tested before the turbine is placed in service
The over speed trip of a steam turbine
Is installed on all turbines
Turbine overspeed trip
Will close the steam stop valve to the turbine
Turbine lubricating oil
Can be used to operate the turbine governor
The purpose of turbine glands is to prevent
Steam from escaping from the turbine
Shaft sealing in high output turbines is done with
Labyrinth seals
When the steam pressure drop occurs in only the stationary members or components of a turbine, the turbine is known as
An impulse unit
A large reaction turbine will have
Steam pressure dropping through moving and stationary sections
Turbine speed can be fine tunes to over 10% over the rated steam by using a
Hand speed control
Turbine thrust bearings are fixed to the casing to prevent axial movement of the spindle by contracting a component on the shaft known as a
Collar
Shaft sealing carbon glands are
Self lubricating
Reaction turbines
Have a pressure drop through the moving and stationary blades
Reaction turbines
Have a velocity increase in the fixed blading
In an impulse turbine
The steam pressure is reduced in the nozzles
The steam turbine that has a pressure drop across every set of blades is the ___ turbine
Reaction
When starting a steam turbine it is customary practice to
Test the over speed trip as soon as running speed is attained
In an impulse turbine, what prevents a pressure drop in the passage of steam through the blades?
The space between the blades
Impulse turbines
Have no pressure drop through the moving blades
The overspeed trip of a steam turbine
Is installed on all turbines
In an impulse turbine, all of the steam pressure drop takes place in the
Stationary nozzles
A turbine speed over trip
Trips the turbine is it is overloaded
In theory, impulse turbines
Have no pressure drop through the moving blades
The principle of an impulse turbine is that the
- steam pressure is reduced in the stationary nozzles
- high velocity steam will impinge upon the blades
In a reaction turbine the steam pressure ___ in passing through moving blades, as well as the stationary nozzles or blades
Drops
In a reaction steam turbine
Expansion takes place in the fixed and moving blades
Two of the more important methods of classifying a steam turbine are by the stationary steam passages and the
Rotor flow passages
Impulse and reaction are two different types of
Steam turbines
The stationary passage of reaction turbines is the
Fixed blade
Blades or ___ form the rotor flow passages in impulse turbines
Buckets
