Fluid fuel burner with automatic fuel shut-off valve

In a fluid fuel burner having an atomizing nozzle receptive of a supply of fuel through a fuel tube therein and receptive of a supply of air under pressure through an air tube therein for atomizing the fuel, the improvement comprising fuel valving means responsive to the pressure of the air in the air tube for normally preventing the passage of fuel from the fuel tube to the nozzle until the air pressure rises above a given value and for shutting off the passage of fuel from the fuel tube to the nozzle when the air pressure falls below a given value, the fuel valving means comprising the fuel tube having a first diameter and a nozzle including a fuel feed passage having a diameter smaller than that of the fuel tube and disposed concentrically with respect thereto, a fuel shut-off rod disposed in the fuel tube and having a diameter less than that of the fuel tube to enable fuel to flow therearound and through the fuel tube and having a valve head at one end thereof nearest the nozzle and configured to close the fuel passage when disposed therein and means mounting the rod for sliding movement in the fuel tube, in response to changes in air pressure, between the first position wherein the valve head extends into the fuel feed passage closing same to the supply of fuel and a second position wherein the valve head is retracted into the fuel tube enabling fuel to flow therearound and into the fuel feed passage, the mounting means comprising a piston connected to the other end of the rod and having a bearing surface thereon, means including the piston bearing surface for defining piston air chamber, means for communicating air from the air tube to the piston air chamber and spring means biasing the piston against the force of the air in the piston air chamber to normally maintain the rod in the first position until the air pressure rises above a given value, wherein the air communicating means comprises an air passage between the air tube and the piston air chamber and a second valving means responsive to the air pressure in the air passage for normally preventing the passage of air from the air tube to the piston air chamber until the pressure rises above a given value and for shutting off the passage of air from the air tube to the piston air chamber when the air pressure falls below a given value.