||12-14-2008 11:25 AM
Question about gas burner design
I recently scavenged an gas valve and burner from an old water heater. I noticed an odd thing in the design of the burner. The gas line does not connect directly to the burner, instead it ends about 2 inches below the burner plate itself. There is a hole in the gas line, and the gas looks like it rises up through open air, hits the burner plate, flows outward to the burner holes at the edge of the plate where it burns.
So the gas is lighter than air and rises up to the burner without any containment at all? It doesn't dissipate in the open air? How come the gas rising in the open air doesn't ignite? Does it need to mix with air before it can burn?
I've noticed the burner in a wall furnace seems to be of a similiar design, with the gas from the gas valve rising through open air before reaching the burner itself.