G1-G3 Assignments Flashcards
List seven performance characteristics of an atmospheric burner:
- complete _______
- rapid _______ of flames
- quiet _______
- immediate _______
- stable _____
- uniform _____
- wide ________ rate
- complete combustion
- rapid carryover of flames
- quiet operation
- immediate ignition
- stable flame
- uniform heating
- wide turndown rate
List the six main components of an atmospheric burner.
- burner ports
- burner head
- venturi
- orifice
- mixing tube
- primary air shutter
Why is a luminous flame yellow?
does not premix gas and air before combustion
Explain the operation of an atmospheric burner.
Premix of some combustion air before ignition produces a blue or bunsen flame which is smaller and more stable
State Bernoulli’s Theorem.
when velocity increases, pressure decreases and vice versa
What are the limits of flammability of natural gas?
4–14% gas to air mix
What are two methods of measuring flame speeds?
- bunsen burner
2. 1 in diameter tube
What is the flame speed of natural gas for each measurement method?
- bunsen burner – 12 in/sec
2. tube method – 25 in/sec
Referring to the graph in Figure 6, which is the fastest burning gas: hydrogen or acetylene?
hydrogen (see graph fig 6) G1
When referring to the graph in Figure 6, what is the burning velocity of acetylene?
8.6 ft/sec ( see graph fig 6) G1
Name the three zones of a bunsen flame.
- inner cone
- outer cone
- outer mantle
In which zone of the bunsen flame is the gas completely burned?
outer cone
The maximum flame speed of natural gas occurs at what mixture of gas and air ?
10%
What is port loading?
amount of gas-air mixture going through a port
For most applications, what is the port loading for natural gas?
25,000-30,000btus per square inch of port area
What are two most common results of unstable flames?
flashback, liftoff
Under what conditions does flashback occur?
- reduced flow velocity
- faster burner gases
- underfed burner
Under what conditions does flame liftoff occur
- lower burning speed
- increased flow velocity
- shallow ports
What conditions may cause a waving flame?
- cracked heat exchanger
2. draft
What conditions cause a flame rollout?
over-firing or vent blockage
On a non-aerated pilot burner, what would cause a lazy yellow flame?
orifice too large
On a non-aerated pilot burner, what causes a noisy lifting blowing flame?
high gas pressure
On an aerated pilot burner, what conditions cause a small blue flame? (3)
- low gas pressure
- clogged pilot burner orifice
- clogged filter
On an aerated pilot burner, what conditions may cause a hard sharp flame? (2)
- orifice too small
2. use of manufactured gas
List the three main functions of a pilot burner.
- to ignite _____ burner flame
- to provide a mount for the ________
- to heat the __________ or power pile
- to ignite main burner flame
- to provide a mount for thermocouple
- to heat thermocouple or powerpile
List the two main types of pilot burners.
- aerated
2. non-aerated
Name two types of single port burners.
- inshot
2. upshot
What are some of the advantages of a multiport burner?
- provide good _____ transfer
- spread flames for secondary ___ to reach them
- provide stable ____ flames
- provide good heat transfer
- spread flames for secondary air to reach them
- provide stable blue flames
Name some common types of multiport burners.
- drilled port
- drilled pipe
- slotted port
- ribbon port
What are some of the advantages of cast iron drilled port burners with small raised bosses for each port?
- provide greater ____ length reducing flashback
- more opportunity for secondary ____ to surround the flame jet
- provide greater port length reducing flashback
2. more opportunity for secondary air to surround the flame jet
What is the range of port sizes for drilled port burners.
- no larger than #__
- no smaller than #__
- no larger than #29
2. no smaller than #42
What are the critical factors in a drilled pipe burner design?
- port ___
- total port ___
- ratio of port area to cross _____
- total _____
- distance from mixer to first ____
- port size
- total port area
- ratio of port area to cross section
- total length
- distance from mixer to first port
What are the disadvantages of the slotted port burner?
- because slots must be ______ subject to plugging
- _____ of slot causes warping in hot places
- because slots must be narrow subject to plugging
2. length of slot causes warping in hot places
Which type of fuel gas is specified for a sandpan burner?
CH4
Which type of burner uses a ceramic burner for a radiating surface?
Infrared radiant burner.
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?
barber burner
Where in relation to the combustion chamber would the combustion air blower be located in a forced draft burner system?
upstream of the combustion chamber
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?
natural draft burner
Which type of burner is equipped with a blower that produces just enough pressure to overcome the resistance of the burner and the appliance?
forced draft burner
Which type of burner has the fan located at the flue outlet of the appliance?
induced draft burner
Which type of burner is equipped with a fan or blower that produces sufficient pressure to overcome the resistance of the burner only?
fan assist burner
Which type of burner mixes the required amount of air and gas before ignition?
pre-mix burner
What device does an aspirating burner use to regulate the gas supply?
zero governor
Which type of burner mixes the required air and gas with a mechanical device?
blower mix burner
Which component of a dual fuel burner directs the air fuel mixture to the appropriate part of the combustion chamber?
the blast tube
