Operation and Maintenance Flashcards
(14 cards)
What is a hydrostatic test? Explain.
A very common procedure performed on boilers.
The unit gets completely filled with water, making sure any air is removed. Then water (hydraulic) pressure is applied at 1.5x the maximum allowable working pressure of the boiler.
What is pressure explosion?
A ruptured tube or crack that allows steam or water to escape to the point of the boiler requiring shutdowns
What is refractory?
The protective layer of material that is applied to various parts of the boiler to withstand high temperatures and abrasions
What is thermal shock?
When strong internal stresses are produced in metal, such as when it is subjected to a sudden change in temperature
What is water hammer?
A series of shocks caused by a sudden change in velocity of water or other liquids flowing inside a pipeline
T/F: Automatic fire packaged boilers do not need supervision from an operator.
False - all devices and boilers require supervision and occasional testing & maintenance.
What is the (general) preliminary preparation for startup of a new or long out-of-operation boiler before it can be used in continuous operation?
1) make sure the boiler has a valid inspection certificate (without, it may be illegal to start up)
2) inspect the fireside and waterside of the boiler to make sure that no foreign matter Is left behind (ex. tools, rags)
3) if waterside of boiler is dirty or coated with grease, clean the boiler chemically
4) make sure the firing equiptment is ready for startup BEFORE filling with water
Why should a boiler be fired up as soon as it’s filled with water?
In order to heat the water sufficiently enough to drive off the dissolved gases and prevent corrosion
When a boiler is out of service for a long or short period of time, what are the 2 layup methods?
Dry method (out of service for a prolonged period)
Wet method (can be placed into service in a relatively short time period)
What are the 2 methods of detecting cracks in the tube ends and tube sheets ?
-Dye-penetrant method
-Black light
What is the difference of natural draft and mechanical draft ?
Natural draft furnaces rely on the natural convection of warm air to move combustion gases out of the chimney
Mechanical drafts is produced by a fan or blower
What is the difference between forced drafts vs induced drafts ?
Forced draft uses fans to push air into a system, creating positive pressure, while induced draft uses fans to draw air out of a system, creating negative pressure.
What is a U-tube gauge used for and how is it used?
-U-tube gas gauge is designed to measure furnace draft or pressure.
-One end is open to the atmosphere and the other end is connected to the inside of the furnace.
U-tube gauge is also known as a manometer
