Burner with variable port area

摘要

A fuel burner includes a tube extending from a first end to a second end and including a central passage and fluid directing structure for directing a mixture of air and combustible fuel radially through the tube. The fluid directing structure collectively defines a total flow area. A blocking member is axially movable within the central passage between a first condition blocking a first percentage of the total flow area and a second condition blocking a second percentage of the total flow area different from the first percentage to control the flow of the mixture of air and combustible fuel through the fluid directing structure from the first end to the second end of the tube to be ignited.