Abstract: A high pressure burner has an integral pilot and is employed in conjunction with a direct fired heater. The burner produces a long flame within the heating tube of the exchanger and therefore more efficiently transfers the heat of combustion into the medium being heated.The burner comprises an elongated mixing barrel attached to a control block. The main fuel gas along with the pilot gas enters the interior of the block and flows therethrough and through an orifice where the gas admixes with air in an unusual manner, and the mixture continues through the mixing barrel. Combustion of the gaseous mixture occurs downstream of the barrel.When the main fuel supply is turned off, the pilot gas supply flows through the burner assembly and forms a standing flame at the end thereof; and when the main fuel supply is opened, an elongated flame is established which extends a long way down the fire tube, thereby heating a large surface area of the fire tube, thus avoiding undue heating of any isolated area.