Mixed-firing burners for use with pulverized coal and heavy oil

Claim 1

A mixed-firing burner for use with coal and heavy oil comprising a heavy oil supply pipe having a burner tip at one end; a protective pipe surrounding said heavy oil supply pipe; a pipe for supplying air necessary to burn heavy oil and surrounding said protective pipe, said air supply pipe being provided with a guide pipe in its front end; a coal air supply pipe concentrically surrounding said air supply pipe for supplying a mixture of pulverized coal and air; a perforated plate provided at the fore end of said air supply pipe for interconnecting said guide pipe and said air supply pipe, said perforated plate having a great number of perforations formed therin; a cooling medium supply pipe and a protective caster successively surrounding said coal-air supply pipe, said cooling medium supply pipe being supplied with air and having a front end opened to the outside; an air whirler provided between the tip of said protective pipe and said guide pipe; a coal whirler provided between the tip of said air supply pipe and said coal-air supply pipe; and an intermediate whirler located at an intermediate point along the length of said coal-air supply pipe.