2Nd Class Fireman, High Pressure Boilers, Chapter 4, Exam Q&a

Front 1

A line desuperheater is used in conjunction with a ____

Back 1

Pressure-reducing station

Front 2

Some plants are equipped with a ____ instead of a blowdown tank

Back 2

Blowdown separator

Front 3

If steam has a quality of ____ %, it is 98% vapor and contains 2% water

Back 3

98

Front 4

In a heat recovery system, the ___ regulates the flow of makeup water to the flash economizer

Back 4

Proportioning valve

Front 5

A 10 degree Fahrenheit rise in feedwater temperature produces approximately ____ % savings in fuel

Back 5

1

Front 6

A throttling calorimeter is used directly to measure ____

Back 6

Moisture content in steam

Front 7

The flow of steam maintained through a superheater should never be less than ____ % of boiler capacity

Back 7

25

Front 8

When water is boiling, the water in the boiler and steam above it are at ____

Back 8

The same temperature and pressure

Front 9

Water hammer is caused by ____ and can lead to a line rupture

Back 9

Mixing steam and water

Front 10

A steam trap usually has a ____ installed on the inlet line

Back 10

Steam strainer

Front 11

Steam turbines require ____ steam

Back 11

Dry superheated

Front 12

The air ejectors on the condenser of a steam turbine are used to remove air and other noncondensable gases from the ____

Back 12

Condenser

Front 13

Boilers operating at ____ psi or more are required to have two bottom blowdown valves mounted on the blowdown line

Back 13

100

Front 14

When ____ fills an inverted bucket steam trap, the bucket loses buoyancy and sinks to open the discharge valve

Back 14

Condensate

Front 15

Failure to maintain steam flow will result in ____ superheater tubes

Back 15

Overheating of

Front 16

Watertube boilers can be fitted with ____ to increase the heat content of the steam

Back 16

Superheaters

Front 17

The bellows of a thermostatic steam trap is usually filled with a(n) ____ and water solution to increase the sensitivity of the trap

Back 17

Alcohol

Front 18

Although the condensate tank is vented, it is possible to have a pressure buildup caused by ____

Back 18

Leaking steam traps

Front 19

According to the ASME code, it the MAWP exceeds ____ psi, the blowdown lines and the fittings must be composed of materials suitable for the temperature and pressures allowed

Back 19

125

Front 20

A steam trap can be tested with a(n) ____ to determine if it is working properly

Back 20

Ultrasonic device

Front 21

In large steam boiler plants, a(n) ____ is necessary to provide the extra capacity required to handle changing loads and peak flows of condensate

Back 21

Surge tank

Front 22

A ____ steam trap is a steam trap that has a single movable disc that rises to allow the discharge of air and cool condensate

Back 22

Thermodynamic

Front 23

The raw makeup water system generally has a float chamber located at the ____ water level in a surge tank

Back 23

Minimum

Front 24

Transfer pumps are used to transfer the mixture of ____ from a surge tank to the deaerator or directly to the boiler feedwater pumps

Back 24

Condensate and raw makeup water

Front 25

A blowdown valve is located ____ of the water side of a firetube boiler or the mud drum of a watertube boiler.

Back 25

At the lowest part

Front 26

A ____ cools down the blowdown water and steam to protect sewer lines from the high pressure and temperature of the blowdown water.

Back 26

Blowdown tank

Front 27

A blowdown heat recovery system is equipment that reclaims heat that is normally lost during the ____ blowdown process.

Back 27

Continuous

Front 28

Steam ____ is the ratio of dry steam to the total amount of water evaporated

Back 28

Quality

Front 29

A superheater is located in the ____ or in the direct part of the gases of combustion

Back 29

Radiant zone (furnace area) or in the convection section of the boiler

Front 30

____ steam turbines use steam velocity as a force acting in a forward direction on a blade mounted on a wheel

Back 30

Impulse

Front 31

____ steam turbines must use a large amount of the available exhaust steam to maintain maximum efficiency.

Back 31

Noncondensing

Front 32

A steam trap removes ____ from steam lines, increasing the overall efficiency of a steam plant

Back 32

Air and condensate

Front 33

A steam trap that is stuck open will ____

Back 33

Cause steam to blow through.

Front 34

Do firetube boilers have superheated steam?

Back 34

No

Front 35

What is the steam called that leaves the drum?

Back 35

Saturated steam

Front 36

What type of steam do turbines require?

Back 36

Superheated steam

Front 37

Every 35 degrees of superheated steam adds how much plant efficiency?

Back 37

1% per 35 degree increase

Front 38

Why is there a superheater safety valve?

Back 38

To prevent damage to the tubes by keeping a flow of steam through the tubes at all times.

Front 39

What are the three primary categories of steam traps?

Back 39

Mechanical, thermostatic, thermodynamic

Front 40

Name 4 popular steam traps:

Back 40

1: float steam trap

2: thermostatic steam trap

3: inverted bucket steam trap

4: thermodynamic disc steam trap

Front 41

Explain why a steam trap is installed in a boiler.

Back 41

A steam traps prime mission is to remove condensate and air while preventing the escape of live steam from the distribution system.

Front 42

Explain what is a superheater.

Back 42

A superheater is a device that is used to convert saturated steam into superheated steam. It is placed in the path of hot flue gases from the furnace. Superheaters are classified as convection, radiant, or combination of these.

Front 43

What does a free blow drain inform you of?

Back 43

It lets you know when the non-return valve is open.

Front 44

Saturation temperature is the temperature at which _____

Back 44

water and steam are at the same pressure

Front 45

A superheater is a bank of tubes through which steam passes _____

Back 45

after leaving the boiler where additional heat is added to the steam

Front 46

A consistent steam temperature during fluctuations in load can be maintained using _____

Back 46

both radiant and convection superheaters in the same unit

Front 47

A superheater safety valve must be of sufficient capacity to relieve _____ % of the steam that the boiler can produce

Back 47

25

Front 48

The flow of steam through a superheater should never be less than _____ % of boiler capacity

Back 48

25

Front 49

In an average steam turbine, there is a gain of about _____ % in efficiency for every 35 degree Fahrenheit of superheat.

Back 49

1

Front 50

Noncondensing steam turbines are normally used in steam plants that require large amounts of ______

Back 50

low-pressure process or heating steam

Front 51

Condensing steam turbines are commonly used on medium to large units and operate with an exhaust pressure of _____ vacuum

Back 51

26 in. Hg to 29 in. Hg

Front 52

To produce the force in an impulse steam turbine, a _____ is located before each stage

Back 52

nozzle

Front 53

Most steam turbines are designed to have a steam velocity that is ____

Back 53

twice as great as the blade velocity

Front 54

_____ is a method in which the energy from steam is extracted using multiple stages in a turbine to reduce the steam velocity and pressure in a short time.

Back 54

velocity compounding

Front 55

The temperature drop across a steam trap is called _____

Back 55

subcooling

Front 56

Most thermostatic steam traps operate with _____ subcooling

Back 56

20 degrees Fahrenheit to 40 degrees Fahrenheit

Front 57

Float thermostatic steam traps are used generally in plants with pressures up to _____ psi

Back 57

125

Front 58

A(n) ____ steam trap has no condensate backup

Back 58

inverted bucket

Front 59

Bimetallic steam traps normally operate with _____ subcooling

Back 59

50 degrees Fahrenheit to 100 degrees Fahrenheit

Front 60

If steam is allowed to enter a return line, it can result in a loss of _____

Back 60

plant efficiency

Front 61

With the sound method, a ____ can be used to test steam traps.

Back 61

mechanic's stethoscope

Front 62

The latest method of testing steam traps uses a sensor fitted inside a sensing chamber to detect the presence of steam or condensate by measuring its _____

Back 62

conductivity

Front 63

Condensate tanks and pumps are installed at the _____

Back 63

lowest points in each building where steam is being used

Front 64

A pressure buildup in a condensate tank is prevented by a(n) _____

Back 64

atmospheric vent line

Front 65

In a larger steam boiler plant, a surge tank is vented to the atmosphere and is equipped with a(n) ____ for cleaning and repairs.

Back 65

manhole

Front 66

_____ are used to transfer the mixture of condensate and raw makeup water to the deaerator or directly to the boiler feedwater pumps.

Back 66

transfer pumps

Front 67

In a raw makeup water system, a float operates a makeup water valve to maintain the ____ in the tank.

Back 67

minimum water level

Front 68

Some plants are equipped with a _____ instead of just a condensate return tank.

Back 68

Condensate surge tank

Front 69

Saturated steam is ______

Back 69

In equilibrium with water at the same temperature and pressure.

Front 70

The two parts of a bimetallic element expand and contract differently when exposed to changes in ______

Back 70

Temperature

Front 71

Superheater tubes are protected from warping or burning out by ______

Back 71

A continuous flow of steam.

Front 72

A desuperheater is an accessory used to _____ to make it suitable for a process.

Back 72

Remove heat from superheated steam.

Front 73

Some _____ moisture separators automatically open and close because they use a wax that expands and contracts with temperature changes.

Back 73

Variable orifice