Burner for use with fluid fuels

Claim 1

A diffusion flame burner for fluid fuels which comprises a fuel chamber having a fluid-tight bottom portion defining an air inlet zone, a top portion defining a combustion zone, and a fluid-tight side portion between said bottom portion and said top portion, said fuel chamber being open to the atmosphere only at its said top portion and being divided into upper and lower fuel zones, metal sponge having a pore size of 0.1 to 0.5 mm average diameter packed in said upper fuel zone for controlling the flow of fuel therethrough towards the combustion zone, said metal sponge being exposed to the atmosphere and unobstructed at its upper surface, said lower fuel zone constituting a fuel inlet zone adapted to be connected to a fuel supply and said upper packed fuel zone constituting a fuel outlet zone adjacent to and communicating with said combustion zone, and a plurality of combustion air tubes passing through said fuel chamber from said bottom portion to said top portion for conducting primary combustion air through said chamber from said air inlet zone to substantially the entire area of the surface of said fuel outlet zone adjacent to and communicating with said combustion zone in confined streams out of contact with fuel in said chamber, whereby, during the use of the burner primary combustion air flows through the combustion air tubes into the combustion zone where it reacts with the fuel which flows upwardly and through said fuel outlet zone into the combustion zone thereabove, said fuel and said primary combustion air mixing only in said combustion zone by low velocity diffusion, and the resulting fuel-air mixture burning as a diffusion flame in said combustion zone, the bore of each of said combustion air tubes being 0.01-1.0 cm2 where it opens into the combustion zone and the bores of the tubes accounting for at least 25 percent of the surface of said fuel outlet space adjacent to the combustion zone.