Introduction to Boilers - Unit 12 Chapter 51 Flashcards
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.
separate the water from the steam.
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.
portion of the boiler not filled with water.
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.
water.
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.
reduce building costs.
Power boilers usually require_____blowdown valves. a) 1 b) 2 c) 3 d) 4
2
High-pressure boilers operate at pressures above a) 1000 kPa b) 500 kPa c) 2500 kPa d) 101.3 kPa
101.3 kPa
A_____is basically a closed container, partially filled with water which is evaporated into steam under pressure by the application of heat.
steam boiler
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.
hot water boiler
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.
Baffle
_____ 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.
Blowdown valves
_____, 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.
Boiler failure
The _____, also called the furnace or firebox, is where air and fuel combine in a chain reaction to cause sustained burning.
Combustion chamber
_____ are the hot gases from the fire. These are also called “flue gases”.
Combustion gases
The _____ is the path that the combustion gases travel along the length of the boiler.
Combustion gas pass
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 ____.
Condensate
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.
Drum
_____ 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.
Externally-fired boiler
_____ 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.
Feedwater
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.
Firetube boiler
A _____ on a boiler is any valve, gauge, regulating or controlling device, flange, pipe fitting or other attachment on the boiler.
Fitting
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.
Flame scanner
_____ are the hot gaseous products from the fire. These are often referred to as “combustion gases”.
Flue gases
A _____ supplies air to the furnace for the combustion process.
Forced draft fan
A _____ is a strong tubular glass used to indicate the water level in a steam boiler.
Gauge glass
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.
Generally supervised boiler
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.
Handhole
A _____ is a large pipe which supplies to, or collect from, a series of smaller pipes or tubes. It is also called a manifold.
Header
_____ 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.
Heads
_____ 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.
Heating surface
A _____ is one which operates at pressure above 101.3 kPa. They are also called power boilers.
High-pressure steam boiler
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.
Horizontal Return Tubular (HRT) boiler
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.
Hot water boiler
3 types of hot water boiler
. Low-pressure hot water heating boiler . Hot water supply boilers or water heaters or hot water tanks . High temperature hot water boilers
Hot water supply boilers are not usually considered to be low-pressure heating boilers unless one or more of the following is exceeded:
. Capacity - 454 L . Temperature - 93 •C . Energy input - 58.7 kW
An _____ draws combustion gases out of the boiler and discharges them up the chimney.
Induced draft fan
An _____ has the combustion chamber located within the shell of the boiler, or a furnace surrounded by watertubes.
Internally-fired boiler
