Chapter 92- Gas Burners For Heating Boilers Flashcards Preview

Power Engineering- 4th Class > Chapter 92- Gas Burners For Heating Boilers > Flashcards

Flashcards in Chapter 92- Gas Burners For Heating Boilers Deck (30):
1

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

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

2

There are two classifications of gas burners what are they

Pre mix burner
After- mix burner

3

Define a premix burner

Combustion air is mixed with gas inside the burner

4

Define an after mix burner

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

5

Is a atmospheric burner a pre mix or after mix burner

Pre mix

6

The pre mix percentage in an atmospheric affects what

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.

7

Burner heads maybe

A variety of shapes and sizes depending on there application

8

What is the most common type of burner head?

The rectangle type used in heating boilers

9

What is the most common application of a refractory type burner

Fire tube boilers

10

A major advantage of a refractory burner

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

11

Disadvantage of a refractory burner

More complex, higher cost

12

Ring burner pre mix or after mix

After mix

13

What do deflector rings in a ring burner accomplish?

Provide intimate mixing of the air and fuel

14

Advantage of natural gas

Storage is not required for fuel as it is pipelined in

15

Disadvantage of natural gas

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

16

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

Secondary air

17

The amount of premix air to an atmospheric burner should be

30- 40%

18

A refractory burner disadvantage is

High initial cost

19

A very common packaged oil has burner is the

Ring burner

20

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

Rectangular burner

21

Atmospheric burners are used for

Gas stoves
Hot water heaters
Heating furnaces

22

An intermittent pilot

Lights the main flame and remains on with it

23

A continuous pilot is also known as a __________ pilot

Standing

24

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

Interrupted

25

An example of the after mix burner is the

Ring burner

26

A hydra motor valve

Is slow to open and quick to close

27

A solenoid gas fuel valve

Is held closed by fuel pressure

28

Diaphragm gas valves use________ to open the valve

Gas pressure

29

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

A diaphragm gas valve

30

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

Puff back