Introduction to Boilers - Unit 12 Chapter 51

Question 0

The steam space of a boiler must be large enough to a) accommodate all the steam riser tubes. b) separate the water from the steam. c) accommodate a steam separator. d) keep the steam pressure down.

Answer 0

separate the water from the steam.

Question 1

The steam space of a boiler consists of a) highest point of the heating surface. b) portion of the boiler not filled with water. c) inside area of the economizer. d) portion of the boiler below the waterline.

Answer 1

portion of the boiler not filled with water.

Question 2

All parts of the boiler exposed to fire or flue gases must be covered by a) blanket insulation. b) metal cladding. c) refractory. d) water.

Answer 2

water.

Question 3

A steam boiler should be compact in design in order to a) allow a larger steam generating capacity. b) reduce the size of the feedwater supply line. c) reduce the size of the stack. d) reduce building costs.

Answer 3

reduce building costs.

Question 4

Power boilers usually require_____blowdown valves. a) 1 b) 2 c) 3 d) 4

Answer 4

2

Question 5

High-pressure boilers operate at pressures above a) 1000 kPa b) 500 kPa c) 2500 kPa d) 101.3 kPa

Answer 5

101.3 kPa

Question 6

A_____is basically a closed container, partially filled with water which is evaporated into steam under pressure by the application of heat.

Answer 6

steam boiler

Question 7

A_____is a closed container, but it is completely filled with water. By applying heat, the temperature and pressure of water is raised but no steam is generated.

Answer 7

hot water boiler

Question 8

A_____is a wall, barrier or panel used to change the direction of flow of a liquid or gas. On the waterside of a boiler, _____ maybe used to direct the flow of water inside drums or headers. On the fireside of the boiler, _____ maybe used to redirect the flow of hot combustion gases through banks of tubes. Fireside _____ are usually made of high temperature refractory material.

Answer 8

Baffle

Question 9

_____ are located on the line leading from the lowest part of the waterside of the boiler. Power (high pressure) boilers usually require a fast opening (also called a guard valve) and a slow opening valve. Heating (low pressure) boilers usually only require one _____ valve.

Answer 9

Blowdown valves

Question 10

_____, a term usually applied to the pressurized parts of the boiler, occurs when ruptured or cracked tube allows high-pressure steam or water to escape, requiring the boiler to be shut down.

Answer 10

Boiler failure

Question 11

The _____, also called the furnace or firebox, is where air and fuel combine in a chain reaction to cause sustained burning.

Answer 11

Combustion chamber

Question 12

_____ are the hot gases from the fire. These are also called “flue gases”.

Answer 12

Combustion gases

Question 13

The _____ is the path that the combustion gases travel along the length of the boiler.

Answer 13

Combustion gas pass

Question 14

When steam from a boiler is used for heating, processing, or power generation, heat energy is given up to the process and the steam condenses. The water formed from condensing steam is called ____.

Answer 14

Condensate

Question 15

The boiler shell, together with the heads, forms a _____ to contain the fluid being heated. The term shell and ____ are often used interchangeably. Shell maybe more common in terms of firetube boilers, where _____ is more often used for watertube boilers.

Answer 15

Drum

Question 16

_____ is a boiler with the combustion chamber outside of the boiler shell. This type of furnace is not surrounded by water but is surrounded by brickwork.

Answer 16

Externally-fired boiler

Question 17

_____ is the water that is fed into a steam boiler to replace the water which has been converted to steam and drawn off from the boiler.

Answer 17

Feedwater

Question 18

A _____ is a boiler consisting of a drum containing straight tubes through which the hot combustion gases from the fire travel. Water in the drum surrounds the tubes and the heat from the hot gases is transferred through the tube walls to the water.

Answer 18

Firetube boiler

Question 19

A _____ on a boiler is any valve, gauge, regulating or controlling device, flange, pipe fitting or other attachment on the boiler.

Answer 19

Fitting

Question 20

A _____ is a device used to monitor the flame in a boiler. If the flame is extinguished for any reason, the _____ may send a signal to close the fuel supply valve to prevent a possible explosion.

Answer 20

Flame scanner

Question 21

_____ are the hot gaseous products from the fire. These are often referred to as “combustion gases”.

Answer 21

Flue gases

Question 22

A _____ supplies air to the furnace for the combustion process.

Answer 22

Forced draft fan

Question 23

A _____ is a strong tubular glass used to indicate the water level in a steam boiler.

Answer 23

Gauge glass

Question 24

A _____ is a type of boiler that can operate without continual control by an operator. This type is also known as an automatic or protected boiler.

Answer 24

Generally supervised boiler

Question 25

A _____ is a small, hand-sized inspection, cleaning, and maintenance port leading from the outside of the boiler into the pressure area of the boiler.

Answer 25

Handhole

Question 26

A _____ is a large pipe which supplies to, or collect from, a series of smaller pipes or tubes. It is also called a manifold.

Answer 26

Header

Question 27

_____ are the steel plates which close off the ends of the boiler drum. They are also referred to as end plates. If the shell contains tubes which are held in position by the heads, then they are usually called tube sheets.

Answer 27

Heads

Question 28

_____ includes all parts of the boiler through which heat from the burning fuel is transferred to the waterside of the boiler. It includes all parts of the boiler plates and tubes which have water or steam on one side and are swept by fire or hot combustion gases on the other side.

Answer 28

Heating surface

Question 29

A _____ is one which operates at pressure above 101.3 kPa. They are also called power boilers.

Answer 29

High-pressure steam boiler

Question 30

An _____ is a firetube boiler usually supported in a brick combustion chamber. The hot gases from combustion sweep along the underside of the shell then return through the firetubes to the chimney connection.

Answer 30

Horizontal Return Tubular (HRT) boiler

Question 31

A _____ is a closed vessel completely filled with water to which heat is added to raise the temperature of the water. No steam is generated in this boiler.

Answer 31

Hot water boiler

Question 32

3 types of hot water boiler

Answer 32

. Low-pressure hot water heating boiler . Hot water supply boilers or water heaters or hot water tanks . High temperature hot water boilers

Question 33

Hot water supply boilers are not usually considered to be low-pressure heating boilers unless one or more of the following is exceeded:

Answer 33

. Capacity - 454 L . Temperature - 93 •C . Energy input - 58.7 kW

Question 34

An _____ draws combustion gases out of the boiler and discharges them up the chimney.

Answer 34

Induced draft fan

Question 35

An _____ has the combustion chamber located within the shell of the boiler, or a furnace surrounded by watertubes.

Answer 35

Internally-fired boiler