Control of the immersion heater boiler is done by turning on and off the ______ supply to one or more elements as required.

Control of the immersion heater boiler is done by turning on and off the ______ supply to one or more elements as required.

a) water
b) power
c) steam
d) amperage
e) current

Answer: B

The immersion heater boiler has its elements arranged

The immersion heater boiler has its elements arranged

a) as isolated units in the steam space
b) equally spaced in the steam space
c) outside the boiler shell to provide easy access for maintenance
d) for operation in sequence on the underside of the shell
e) as groups of elements submerged in the water space

Answer: E

Control of the immersion heater boiler is done by

Control of the immersion heater boiler is done by

a) transforming the voltage to a lower value
b) turning the power on and off to the elements as required
c) a float switch
d) increasing and decreasing water flow
e) recirculating boiler water

Answer: B

There are two general designs of electric boilers. They are the

There are two general designs of electric boilers. They are the

a) firetube type and water tube type
b) AC and DC type
c) electrode and immersion type
d) grounded and ungrounded type
e) reverse polarity and negative ground

Answer: C

Immersion boiler tube bundles

Immersion boiler tube bundles

a) act to conduct current through the water
b) can be easily removed from the unit for maintenance purposes
c) cannot be used to regulate steaming capacity
d) have very low electrical resistance
e) operate at only one voltage

Answer: B

An immersion electric boiler capacity can be as high as

An immersion electric boiler capacity can be as high as

a) 1,500 kW
b) 2,100 kW
c) 30,000 kW
d) 16,000 kW
e) 5,000 kW

Answer: A

A __________ is not required on an electrode electric type boiler.

A __________ is not required on an electrode electric type boiler.

a) safety valve
b) gauge glass
c) blow-off valve
d) low water cut-off
e) pressure gauge

Answer: D

One disadvantage of an electric boiler is that it

One disadvantage of an electric boiler is that it

a) requires alternating current
b) requires DC power
c) has no chimney
d) is not very efficient
e) is very expensive to operate

Answer: E

The amount of current passed through the water of an electrode boiler depends on

The amount of current passed through the water of an electrode boiler depends on

a) the depth of the electrodes in the water
b) the control valve setting
c) the steam pressure in the boiler
d) the water quality
e) the water temperature

Answer: A

The steam produced by an electrode type boiler depends on

The steam produced by an electrode type boiler depends on

a) the voltage supplied to the elements
b) the level of water in the basket
c) the number of heating elements engaged
d) the number of baffles
e) the amperage supplied to the elements

Answer: B

The electrode type boiler

The electrode type boiler

a) cannot have a varying load
b) must operate at very constant pressure
c) utilizes bundles of electric elements
d) requires water which conducts electricity
e) will produce hydrogen by electrolysis of water

Answer: D

Electrode boiler capacities can be as high as

Electrode boiler capacities can be as high as

a) 16,000 kW
b) 30,000 kW
c) 1,200 kPa
d) 1,200 kW
e) 30,000 kPa

Answer: B

Operating voltage for an electrode boiler may be as high as

Operating voltage for an electrode boiler may be as high as

a) 30,000 volts
b) 16,000 volts
c) 5,000 volts
d) 550 volts
e) 240 volts

Answer: B

A boiler which incorporates a basket and a basket drain valve is the

A boiler which incorporates a basket and a basket drain valve is the

a) steam generator
b) immersion boiler
c) Sterling boiler
d) electrode boiler
e) thermal flood boiler

Answer: D

Most electric boilers are limited in pressure to about 2100 kPa due to the effect of high temperature on the

Most electric boilers are limited in pressure to about 2100 kPa due to the effect of high temperature on the

a) steam space
b) submerged area
c) boiler fittings
d) vessel structure
e) elements or electrodes

Answer: E

An advantage of an electric boiler is that it

An advantage of an electric boiler is that it

a) is silent in operation
b) can rapidly produce steam
c) can produce steam at very high pressures
d) requires only one blow-off valve
e) does not require a sight glass

Answer: A

An advantage of an electric boiler is, that it

An advantage of an electric boiler is, that it

a) has a high steaming rate
b) can be operated at high pressures and temperatures
c) produces very dry steam
d) has a high efficiency of energy transfer from the electricity to the boiler water
e) does not require an operator

Answer: D

A main disadvantage of an electric boiler is

A main disadvantage of an electric boiler is

a) they are not very compact
b) furnace refractory tends to be high maintenance item
c) vibration requires special footings
d) input energy cost is high
e) energy transfer efficiency is low

Answer: D

Electric boilers

Electric boilers

a) require tall stacks for pollution dispersal
b) tend not to be very compact
c) require sootblowers when fuel is coal
d) have energy conversion efficiencies close to 100%
e) are not as safe as other boilers

Answer: D