Book 1 Chapter 4: Electric Boilers

Question 1

An immersion-type electric boiler has:
A) electrodes
B) no steam space
C) elements
D) tube bundles

Answer 1

C) elements

Question 2

The load on an electrode-type electric boiler is maintained by the:
A) amount of steam space in the boiler
B) amount of electrode covered by water
C) outdoor temperature
D) amount of current flowing through the elements

Answer 2

B) amount of electrode covered by water

Question 3

Output of an immersion electric boiler is regulated by altering the:
A) water level relative to the electrodes
B) water level relative to the elements
C) amount of current flowing through the water
D) amount of current flowing through the elements

Answer 3

D) amount of current flowing through the elements

Question 4

A main disadvantage of an electric boiler is the:
A) high cost of manufacturing
B) high cost of the electricity
C) inefficiency of the energy transfer
D) space requirement per unit output

Answer 4

B) high cost of electricity

Question 5

Electric boilers:
A) require tall stacks for pollution dispersement
B) tend not to be very compact
C) require sootblowers when the fuel is coal
D) have energy conversion effiencies close to 100%

Answer 5

D) have energy conversion effiencies close to close 100%

Question 6

A salinity feeder is an important component of a/an ________ boiler:
A) verticle tubeless
B) electrode-type electric
C) vertical firetube
D) immersion electric

Answer 6

B) electrode-type electric

Question 7

An immersion type of electric boiler:
A) Does everything shown here
B) Depends on water level to regulate steam production
C) Generates heat utilizing a bundle of heating elements
D) Uses pressure to directly regulate energy consumption
E) Passes current through the water

Answer 7

C) Generates heat utilizing a bundle of heating elements

Question 8

In an electrode type of electric boiler:
A) As generating zone water level decreases, current increases
B) More steam is generated when the generating zone level drops
C) Current decreases as pressure drops
D) Current increases as the generating zone level drops
E) Electrical current decreases as pressure goes up

Answer 8

E) Electrical current decreases as pressure goes up

Question 9

Electrode type boilers:
A) Require complex control systems
B) Require external resistance for control
C) Require electrodes to be totally immersed in water
D) Self regulate steam pressure
E) Require microprocessor control

Answer 9

D) Self regulate steam pressure

Question 10

Water level in the generating zone of an electrode type boiler:
A) Is maintained by means of a feedwater regulator
B) Has no effect on pressure
C) Is governed by feedwater flow
D) Is governed by load fluctuations
E) Is constant

Answer 10

D) Is governed by load fluctuations

Question 11

A rise of steam pressure in the generating zone of an electrode boiler leads to:
A) A drop in water level in the generating zone
B) More steam output
C) A rise in water level
D) More current demand
E) A requirement of more feedwater

Answer 11

A) A drop in water level in the generating zone

Question 12

Immersion boiler tube bundles:
A) Act to conduct current through the water
B) Cannot be used to regulate steaming capacity
C) Operate at only one voltage
D) Have very low electrical resistance
E) Can be removed from the unit for maintenance purposes

Answer 12

E) Can be removed from the unit for maintenance purposes

Question 13

Electric boilers:
A) Tend not to be very compact
B) Require sootblowers when fuel is coal
C) Have energy conversion efficiencies close to 100%
D) Require tall stacks for pollution dispersment
E) Are not as safe as other boilers

Answer 13

C) Have energy conversion efficiencies close to 100%

Question 14

In an electrode type electric boiler the generating zone:
A) Is less efficient than an immersion type
B) Generates more steam as water levels falls
C) Is less efficient when water level rises
D) Uses more current when water level rises
E) Generates more steam as water level rises

Answer 14

E) Generates more steam as water level rises

Question 15

Due to the effect of high temperature on the electrodes, Electric boilers are:
A) Operated at lower pressures below 2100kPa
B) Able to withstand any pressure
C) Operated at pressure up to 2100 psi
D) Limited to 1100kPa
E) Required to be used only for large scale industrial processes

Answer 15

A) Operated at lower pressure below 2100kPa

Question 16

An advantage of an electric boiler is the:
A) Requirement for duct work and chimneys
B) High cost of the electricity
C) Compactness of the boiler
D) Inefficiency of the energy transfer
E) High cost of manufacturing

Answer 16

C) Compactness of the boiler

Question 17

Since pure water will not conduct electricity a predetermined amount of electrolyte (____) is dissolved in the water.
A) HCl
B) NaSO3
C) H2SO4
D) NaOH
E) NaCl

Answer 17

E) NaCl

Question 18

A main disadvantage of an electric boiler is the:
A) Inefficiency of the energy transfer
B) High cost of manufacturing
C) Requirement for duct work and chimneys
D) Space requirement per unit output
E) High cost of the electricity

Answer 18

E) High cost of the electricity

Question 19

Output of an immersions electric boiler is regulated by altering the:
A) Water level relative to the electrodes
B) The voltage applied to the boiler
C) Amount of current flowing through the elements
D) Amount of current flowing through the water
E) Water level relative to the elements

Answer 19

C) Amount of current flowing through the elements

Question 20

In an immersion-type electric boiler scale tends to form on the:
A) Firetube bundles
B) Electrodes
C) Walls of the basket
D) Watertube bundles
E) Elements

Answer 20

E) Elements

Question 21

The load on an electrode-type electric boiler is maintained by the:
A) Amount of current flowing through the elements
B) The voltage applied to the boiler
C) Amount of electrode covered by water
D) Outdoor temperature
E) Amount of steam space in the boiler

Answer 21

C) Amount of electrode covered by water

Question 22

In the electrode type boiler the electrodes are located in the:
A) Windbox
B) Central generating chamber
C) Firebox
D) Watertube section
E) Firetube section

Answer 22

B) Central generating chamber

Question 23

Electric boilers:
A) Have energy conversion efficiencies close to 100%
B) Add to pollution with the production of ashes and smoke
C) Require soot blowers when the fuel is coal
D) Require tall stacks for pollution dispersement
E) Tend not to be very compact

Answer 23

A) Have energy conversion efficiencies close to 100%

Question 24

The electrode type electric boiler consists of two cylindrical chambers:
A) The inner one forming the regulating compartment and the other generating compartment
B) The inner one forming the steam compartment and the other the generating compartment
C) The inner one forming the generating compartment and the other the regulating compartment
D) The inner one forming the regulating compartment and the other the steam compartment
E) The inner one forming the fire compartment and the other the generating compartment

Answer 24

C) The inner one forming the generating compartment and the other the regulating compartment

Question 25

An immersion-type electric boiler has:
A) Elements
B) Tube bundles
C) Electrodes
D) Water tubes
E) No steam space

Answer 25

A) Elements