Air pulsation for combustors

In a combustor having a cylindrical drum formed of water cooled pipes joined by perforated strips so as to be air porous, said drum being slowly rotated on its axis and having an upper open end of receiving burnable material and a lower end for discharging ashes or nonburnable material, the combination comprising, a windbox fitted to the lower portion of said drum for delivering air to penetrate and react with the material being burned, means for delivering air to said windbox, a valve disposed in said air delivery means and drive means connected to said valve for continually arresting and commencing air flow so that air is delivered to the drum in fluctuating pressure pulses, whereby the fluctuating pressure pulses of air enhance complete combustion of the burnable material, said valve includes a valve plate mounted in said windbox for rotation through an air blocking position and an air passing position, and said drive means includes a motor for rotating said valve plate and thereby generating said fluctuating pressure pluses.