G1-G3 Assignments

Question 1

List seven performance characteristics of an atmospheric burner:

1. complete _______
2. rapid _______ of flames
3. quiet _______
4. immediate _______
5. stable _____
6. uniform _____
7. wide ________ rate

Answer 1

1. complete combustion
2. rapid carryover of flames
3. quiet operation
4. immediate ignition
5. stable flame
6. uniform heating
7. wide turndown rate

Question 2

List the six main components of an atmospheric burner.

Answer 2

1. burner ports
2. burner head
3. venturi
4. orifice
5. mixing tube
6. primary air shutter

Question 3

Why is a luminous flame yellow?

Answer 3

does not premix gas and air before combustion

Question 4

Explain the operation of an atmospheric burner.

Answer 4

Premix of some combustion air before ignition produces a blue or bunsen flame which is smaller and more stable

Question 5

State Bernoulli’s Theorem.

Answer 5

when velocity increases, pressure decreases and vice versa

Question 6

What are the limits of flammability of natural gas?

Answer 6

4–14% gas to air mix

Question 7

What are two methods of measuring flame speeds?

Answer 7

1. bunsen burner

2. 1 in diameter tube

Question 8

What is the flame speed of natural gas for each measurement method?

Answer 8

1. bunsen burner – 12 in/sec

2. tube method – 25 in/sec

Question 9

Referring to the graph in Figure 6, which is the fastest burning gas: hydrogen or acetylene?

Answer 9

hydrogen (see graph fig 6) G1

Question 10

When referring to the graph in Figure 6, what is the burning velocity of acetylene?

Answer 10

8.6 ft/sec ( see graph fig 6) G1

Question 11

Name the three zones of a bunsen flame.

Answer 11

1. inner cone
2. outer cone
3. outer mantle

Question 12

In which zone of the bunsen flame is the gas completely burned?

Answer 12

outer cone

Question 13

The maximum flame speed of natural gas occurs at what mixture of gas and air ?

Answer 13

10%

Question 14

What is port loading?

Answer 14

amount of gas-air mixture going through a port

Question 15

For most applications, what is the port loading for natural gas?

Answer 15

25,000-30,000btus per square inch of port area

Question 16

What are two most common results of unstable flames?

Answer 16

flashback, liftoff

Question 17

Under what conditions does flashback occur?

Answer 17

1. reduced flow velocity
2. faster burner gases
3. underfed burner

Question 18

Under what conditions does flame liftoff occur

Answer 18

1. lower burning speed
2. increased flow velocity
3. shallow ports

Question 19

What conditions may cause a waving flame?

Answer 19

1. cracked heat exchanger

2. draft

Question 20

What conditions cause a flame rollout?

Answer 20

over-firing or vent blockage

Question 21

On a non-aerated pilot burner, what would cause a lazy yellow flame?

Answer 21

orifice too large

Question 22

On a non-aerated pilot burner, what causes a noisy lifting blowing flame?

Answer 22

high gas pressure

Question 23

On an aerated pilot burner, what conditions cause a small blue flame? (3)

Answer 23

1. low gas pressure
2. clogged pilot burner orifice
3. clogged filter

Question 24

On an aerated pilot burner, what conditions may cause a hard sharp flame? (2)

Answer 24

1. orifice too small

2. use of manufactured gas

Question 25

List the three main functions of a pilot burner. 1. to ignite _____ burner flame 2. to provide a mount for the ________ 3. to heat the __________ or power pile

Answer 25

1. to ignite main burner flame 2. to provide a mount for thermocouple 3. to heat thermocouple or powerpile

Question 26

List the two main types of pilot burners.

Answer 26

1. aerated | 2. non-aerated

Question 27

Name two types of single port burners.

Answer 27

1. inshot | 2. upshot

Question 28

What are some of the advantages of a multiport burner? 1. provide good _____ transfer 2. spread flames for secondary ___ to reach them 3. provide stable ____ flames

Answer 28

1. provide good heat transfer 2. spread flames for secondary air to reach them 3. provide stable blue flames

Question 29

Name some common types of multiport burners.

Answer 29

1. drilled port 2. drilled pipe 3. slotted port 4. ribbon port

Question 30

What are some of the advantages of cast iron drilled port burners with small raised bosses for each port? 1. provide greater ____ length reducing flashback 2. more opportunity for secondary ____ to surround the flame jet

Answer 30

1. provide greater port length reducing flashback | 2. more opportunity for secondary air to surround the flame jet

Question 31

What is the range of port sizes for drilled port burners. 1. no larger than #__ 2. no smaller than #__

Answer 31

1. no larger than #29 | 2. no smaller than #42

Question 32

What are the critical factors in a drilled pipe burner design? 1. port ___ 2. total port ___ 3. ratio of port area to cross _____ 4. total _____ 5. distance from mixer to first ____

Answer 32

1. port size 2. total port area 3. ratio of port area to cross section 4. total length 5. distance from mixer to first port

Question 33

What are the disadvantages of the slotted port burner? 1. because slots must be ______ subject to plugging 2. _____ of slot causes warping in hot places

Answer 33

1. because slots must be narrow subject to plugging | 2. length of slot causes warping in hot places

Question 34

Which type of fuel gas is specified for a sandpan burner?

Answer 34

CH4

Question 35

Which type of burner uses a ceramic burner for a radiating surface?

Answer 35

Infrared radiant burner.

Question 36

Which type of burner is arranged so that the streams of gas/air mixture intersect each other to slow velocity and maintain a stable flame through a wide turndown?

Answer 36

barber burner

Question 37

Where in relation to the combustion chamber would the combustion air blower be located in a forced draft burner system?

Answer 37

upstream of the combustion chamber

Question 38

What is the name for a class of burners that do not require assistance from a fan to supply combustion air or to vent the flue products according to the Natural Gas and Propane Installation code?

Answer 38

natural draft burner

Question 39

Which type of burner is equipped with a blower that produces just enough pressure to overcome the resistance of the burner and the appliance?

Answer 39

forced draft burner

Question 40

Which type of burner has the fan located at the flue outlet of the appliance?

Answer 40

induced draft burner

Question 41

Which type of burner is equipped with a fan or blower that produces sufficient pressure to overcome the resistance of the burner only?

Answer 41

fan assist burner

Question 42

Which type of burner mixes the required amount of air and gas before ignition?

Answer 42

pre-mix burner

Question 43

What device does an aspirating burner use to regulate the gas supply?

Answer 43

zero governor

Question 44

Which type of burner mixes the required air and gas with a mechanical device?

Answer 44

blower mix burner

Question 45

Which component of a dual fuel burner directs the air fuel mixture to the appropriate part of the combustion chamber?

Answer 45

the blast tube