Chapter 14 Book 1 Burners For Boilers Flashcards
Two main classes of gas burners
Atmospheric and power
Atmospheric don’t use a fan where power do
Different type of air mixing
Pre mixing burner and after mixing burner. The pre mixing has the primary air mix with the gas before it reaches the burner head where after mix is the opposite
Atmospheric burners
Is a popular pre mix type burner. Gas passes through a small orifice sometimes controlled by a needle valve and enters a Venturi tube which creates a swirling motions and therefore pulls air in through a disc or plate in the air opening.
Refractory burner
Basically a burner that is surrounded by refractory to heat the fuel gas mix before it completely combusts. Advantages are
Gas air mid is preheated before it enters the furnace giving its higher combustion efficiency
-metal burner parts are protected against high temp by refractory
- has high radiant heat transfer
CON high initial cost due to complex design
What extra aux equipment does oil fired burners have that gas fired don’t
Fuel pump- usually of the rotary pump type such as a gear pump, either single
Or double stage and either single or double pipe. A single pipe is used when there is a short distance to the burner and the oil tank is located about the
Pump the double is used when there is some distance travel and the tank is located below the pump
Electric ignition- oil burners are generally lit electronically to do this there needs to be a step up transformer that take 120v and make it 12000 v between two stainless steel electrodes that are mounted in a ceramic insulator
Fuel oil filter- this is needed so you don’t plug up the atomizing ports in the burner. Usually located between the pump and supply tank.
Time delay oil valve- proper start sequence is very important to avoid puff back or furnace explosion. The time delete valve ensures 10-15 seconds of purge time then the igniter starts and only after the spark going does the oil valve open and light the main burner
