System for spraying fluidized powder circumferentially around a pipe joint

An improved system for spraying fluidized powder circumferentially around a pipe joint comprising a powder applicator ring engageable with a pipe, means for driving the ring circumferentially about said pipe, a pair of circumferentially spaced powder dispensers mounted on said ring and disposed over said pipe joint, a powder fluidization chamber comprising a hollow container adapted to contain a quantity of powder therein, means for sealing said chamber, means for introducing a stream of air into said chamber to fluidize the powder therein, a cylindrical powder recovery canister having a pair of axially opposed powder blowers mounted thereon, said powder blowers having their intakes in communication with the interior of said recovery canister, each powder blower having an outlet from which a stream of air is allowed to pass, a pair of tangential inlet pipes circumferentially spaced and connecting with the interior of said recovery canister, a pair of powder control valves connected to said chamber and in communication with said fluidized powder therein, means for actuating said powder control valves wherein a quantity of fluidized powder is exhausted into an orifice in each powder control valve, means for introducing the exhausted fluidized powder from said powder control valves into the sides of each outlet from said powder blowers, respectively, a supply conduit connecting each said outlet with a respective portion of each powder dispenser for supplying a stream of fluidized powder to each powder dispensing device, a return conduit connecting each tangential inlet pipe of said recovery canister to another portion of each powder dispenser for returning excess powder to said recovery canister, and a fluidization blower having its suction from the atmosphere and from which a stream of fluidizing air is allowed to pass into said chamber.