Chapter 92- Gas Burners For Heating Boilers Flashcards

1
Q

Gas is already in a vapour state, so further vaporization or atomization isn’t necessary so what does the gas burner accomplish

A

It provides a complete and turbulent mixing of gas and combustion air

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2
Q

There are two classifications of gas burners what are they

A

Pre mix burner

After- mix burner

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3
Q

Define a premix burner

A

Combustion air is mixed with gas inside the burner

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4
Q

Define an after mix burner

A

Combustion air is mixed with the gas after it leaves the burner

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5
Q

Is a atmospheric burner a pre mix or after mix burner

A

Pre mix

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6
Q

The pre mix percentage in an atmospheric affects what

A

Increased air entering the nozzle shortens the flame giving it an inner green color. because of faster burning, if air is too high the flame may retreat back into the tube.

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7
Q

Burner heads maybe

A

A variety of shapes and sizes depending on there application

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8
Q

What is the most common type of burner head?

A

The rectangle type used in heating boilers

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9
Q

What is the most common application of a refractory type burner

A

Fire tube boilers

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10
Q

A major advantage of a refractory burner

A

Air and fuel are preheated raising efficiency and lowering the need for excess air

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11
Q

Disadvantage of a refractory burner

A

More complex, higher cost

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12
Q

Ring burner pre mix or after mix

A

After mix

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13
Q

What do deflector rings in a ring burner accomplish?

A

Provide intimate mixing of the air and fuel

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14
Q

Advantage of natural gas

A

Storage is not required for fuel as it is pipelined in

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15
Q

Disadvantage of natural gas

A

If interruption in the gas supply occurs then the plant will shut down

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16
Q

An atmospheric burner has air entering around the burner, which is termed

A

Secondary air

17
Q

The amount of premix air to an atmospheric burner should be

A

30- 40%

18
Q

A refractory burner disadvantage is

A

High initial cost

19
Q

A very common packaged oil has burner is the

A

Ring burner

20
Q

An atmospheric burner head which is very popular on heating boilers Is the

A

Rectangular burner

21
Q

Atmospheric burners are used for

A

Gas stoves
Hot water heaters
Heating furnaces

22
Q

An intermittent pilot

A

Lights the main flame and remains on with it

23
Q

A continuous pilot is also known as a __________ pilot

A

Standing

24
Q

What type of pilot lights the main burner and then shuts off?

A

Interrupted

25
Q

An example of the after mix burner is the

A

Ring burner

26
Q

A hydra motor valve

A

Is slow to open and quick to close

27
Q

A solenoid gas fuel valve

A

Is held closed by fuel pressure

28
Q

Diaphragm gas valves use________ to open the valve

A

Gas pressure

29
Q

What type of gas valves incorporates a relay coil and a gas bleed port

A

A diaphragm gas valve

30
Q

Larger solenoid type oil and gas valves usually delayed opening to prevent

A

Puff back