5th Class Power Engineering Assignment 3 Questions With
Complete Solutions
As a person in charge of a heating plant, describe the procedure
to be followed in the event of a boiler explosion Correct
Answers Even though most boilers are fully automatic, the
boiler operator should pay regular attention to the operation of
the boiler and should consciously follow the instructions
regarding testing and maintenance of fittings and controls in
order to prevent the occurrence of an explosion. If an explosion
does occur, then the person in charge of the boiler or pressure
vessel must notify the proper authorities
Briefly describe how clean steam can be produced Correct
Answers Indirect steam generators may also be used to
generate clean steam
Briefly describe the four conditions necessary for complete
combustion of a fuel Correct Answers An adequate air
(oxygen) supply. Adequate fuel/air mixture, appropriate
combustion temperature for fuel ignition
Briefly describe the operation of a spring- loaded pressure
reducing valve with internal diaphragm Correct Answers
When the water enters the regulator at high pressure, the inner
mechanism constricts the diaphragm to narrow the flow of water
briefly describe the step by step procedure for acid cleaning a
boiler by the circulating method Correct Answers This
involves the use of some type of acid that dissolve the scale. An
,inhibitor is added to the acid to minimize the attack of the acid
on the metal
Briefly describe the two varieties of mechanical atomizing
burner Correct Answers Mechanical pressure atomizing oil
burner, centrifugal atomizing burner
Briefly explain the reasons for allowing pipe expansion Correct
Answers The use of expansion bends is usually preferred for
high pressure work as there is no maintenance involved and little
likelihood of leaks developing
Define "thermal Shock" Correct Answers When metal is
subjected to a sudden change in temperature, the temperature
change will not be even throughout the metal. Expansion and
contraction will not be equal in all parts of the metal. This
causes strong internal stresses in the metal, called "thermal
shock"
Define the term "heating value" as it applies fo boiler fuels
Correct Answers When a unit amount of fuel is burned
completely, the heat produced by this combustion is called the
heating value of fuel
Define the term combustion Correct Answers Combustion is a
chemical process in which a substance reacts rapidly with
oxygen and gives off heat
Describe a forced draft combustion system Correct Answers
Designed for a positive over fire pressure created, in part, by
, resistance to flue gas flow in the stack. Which also operates
under a positive pressure
Describe a fuel oil system suitable for use with two fixed
capacity nozzles Correct Answers Two fixed capacity nozzles-
The primary nozzle is used for startup and low demand during,
the secondary nozzle is used in conjunction with the primary
nozzle when the heat demand is high
Describe a hot water tank Correct Answers A large tank
designed to heat and hold water
Describe a method of igniting an oil burner utilizing electricity
Correct Answers In order to be able to igniter the fuel-air
mixture at start up, a very hot spark is required between the tips
of the two electrodes with applied voltage of 120 to 10,000 volts
Describe a solenoid that might be used in a fuel system. Explain
its operation Correct Answers This valve is similar to the
diaphragm type except that the electromagnetic coil activates the
valve directly, there is no pilot valve
Describe a typical piping arrangement for a steam trap
installation Correct Answers Always install the steam trap in a
location that is accessible by plant personnel. Install a visual
indication of the steam trap performance on all process
applications
Describe an annual inspection that would be carried out on a
typical hot oil system Correct Answers All internal walls and
Complete Solutions
As a person in charge of a heating plant, describe the procedure
to be followed in the event of a boiler explosion Correct
Answers Even though most boilers are fully automatic, the
boiler operator should pay regular attention to the operation of
the boiler and should consciously follow the instructions
regarding testing and maintenance of fittings and controls in
order to prevent the occurrence of an explosion. If an explosion
does occur, then the person in charge of the boiler or pressure
vessel must notify the proper authorities
Briefly describe how clean steam can be produced Correct
Answers Indirect steam generators may also be used to
generate clean steam
Briefly describe the four conditions necessary for complete
combustion of a fuel Correct Answers An adequate air
(oxygen) supply. Adequate fuel/air mixture, appropriate
combustion temperature for fuel ignition
Briefly describe the operation of a spring- loaded pressure
reducing valve with internal diaphragm Correct Answers
When the water enters the regulator at high pressure, the inner
mechanism constricts the diaphragm to narrow the flow of water
briefly describe the step by step procedure for acid cleaning a
boiler by the circulating method Correct Answers This
involves the use of some type of acid that dissolve the scale. An
,inhibitor is added to the acid to minimize the attack of the acid
on the metal
Briefly describe the two varieties of mechanical atomizing
burner Correct Answers Mechanical pressure atomizing oil
burner, centrifugal atomizing burner
Briefly explain the reasons for allowing pipe expansion Correct
Answers The use of expansion bends is usually preferred for
high pressure work as there is no maintenance involved and little
likelihood of leaks developing
Define "thermal Shock" Correct Answers When metal is
subjected to a sudden change in temperature, the temperature
change will not be even throughout the metal. Expansion and
contraction will not be equal in all parts of the metal. This
causes strong internal stresses in the metal, called "thermal
shock"
Define the term "heating value" as it applies fo boiler fuels
Correct Answers When a unit amount of fuel is burned
completely, the heat produced by this combustion is called the
heating value of fuel
Define the term combustion Correct Answers Combustion is a
chemical process in which a substance reacts rapidly with
oxygen and gives off heat
Describe a forced draft combustion system Correct Answers
Designed for a positive over fire pressure created, in part, by
, resistance to flue gas flow in the stack. Which also operates
under a positive pressure
Describe a fuel oil system suitable for use with two fixed
capacity nozzles Correct Answers Two fixed capacity nozzles-
The primary nozzle is used for startup and low demand during,
the secondary nozzle is used in conjunction with the primary
nozzle when the heat demand is high
Describe a hot water tank Correct Answers A large tank
designed to heat and hold water
Describe a method of igniting an oil burner utilizing electricity
Correct Answers In order to be able to igniter the fuel-air
mixture at start up, a very hot spark is required between the tips
of the two electrodes with applied voltage of 120 to 10,000 volts
Describe a solenoid that might be used in a fuel system. Explain
its operation Correct Answers This valve is similar to the
diaphragm type except that the electromagnetic coil activates the
valve directly, there is no pilot valve
Describe a typical piping arrangement for a steam trap
installation Correct Answers Always install the steam trap in a
location that is accessible by plant personnel. Install a visual
indication of the steam trap performance on all process
applications
Describe an annual inspection that would be carried out on a
typical hot oil system Correct Answers All internal walls and
