Gas boilers (burners)?

Question

Could anybody briefly descibe the following functions of a burner and how they fit in with each other.
Venturi, venturi throat, Mixing tube, burner body.
They all seem very closely related.
Thanks

Answer 1

i will describe these components in regard to natural gas firing, fuel oil or coal would be slightly different. I am assuming that you understand venturi effect allready. there must be sufficient primary and secondary air. primary being=the theoretical amount of air required to aid in compete combustion, and secondary air=excess air added at the point of combustion to ensure complete combustion (usually just called excess air). the air supplied is usually pressurized (forced draft fan) so it needs no aid, but the nat. gas needs the venturi tube to increase velocity and help with adomization. basically gas travels into the venturi tube which causes a decrease in cross sectional area, which increases the velocity of the gas. the venturi throat is where the smallest cross sectional area of the tube is (this spot is called the vena contracta) this is where the gas is moving the fastest , then the mixing tube will mix the now fast travelling gas with fast travelling air supplied by the fan (primary air), this mixture is often concidered "lean" , the burner body is usually dish shaped with fins to cause the mixture to spin ,thus allowing more air to be mixed to ensure compete combustion (secondary air). The venturi and throat are made to increase the velocity of the gas , the mixing tube mixes the gas and air bringing it into the explosive range, and the burner body is designed to spin the mixture in order to burn all combustible components and increase heat transfer within the boiler, the body also is a place to add approx 10% more air to make sure you dont send unburned gas out the stack in a "rich" mixture situation. I am assuming this is a small burner for a heating boiler. the components are very small and close together in this application, my source, i am a power generation engineer for the federal government , i specialize in large high pressure steam boilers, burners usually in the 2' to 6' diameter range.

Answer 2

What concerns me is that if I answer these questions, then you end-up getting your CORGI certificate, you will be out-and-about fu*cking-about with people's boilers, and you haven't got a clue what you are doing.

Answer 3

They seem like double dutch to me?Hope some one can answer your question will have to be a gas fitter.

Answer 4

you mean like siblings ??????