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What are the limitations of a surface condenser?
Answers:
It is very bulky and as such requires more floor space.
Its manufacturing, running and maintenance costs are high.
What should be the requirements of an ideal surface condenser used for steam power plants?
Answers:
Uniform distribution of exhaust steam throughout the heat transfer surface of the condenser.
Absence of condensate subcooling.
There should not be any leakage of air into the condenser.
There should not be any tube leakage.
The heat transfer surface in contact with cooling water must be free from any deposit as scaling reduces the efficiency of heat exchangers.
What do you mean by vacuum?
Answer:
Vacuum means any pressure below atmospheric pressure.
How is vacuum in a condenser usually measured?
Answers:
It is measured by means of a Bourdon pressure gauge, which is calibrated to read the pressure in mm of mercury below atmospheric pressure.
If the gauge pressure of a condenser is 630 mm of Hg, what will be the absolute pressure in the condenser?
Answer:
It means the pressure in the condenser is 630 mm below atmospheric pressure. The atmospheric pressure is 760 mm of Hg, the absolute pressure in the condenser.
On what factors does the degree of vacuum in a condenser depend?
Answer:
It depends on the partial pressure of steam and the partial pressure of air in the condenser.
How could air enter the condenser?
Answers:
With the boiler feedwater as dissolved gases.
Flange leakage.
Cooling water (for jet condenser) containing a certain amount of dissolved air in it.
What are the effects of air leakage in the condenser?
Answers:
It increases the backpressure on the turbine with the effect that there is less heat drop and low thermal efficiency of the plant.
The pressure of air in the condenser lowers the partial pressure of steam, which means steam, will condense at a lower temperature and that will require greater amount of cooling water.
It reduces the rate of condensation of steam, because air having poor thermal conductivity impairs the overall heat transfer from the steam-air mixture. Goto Steam Condensers Home Page | 
