Brief Announcement: Optimal Failure Detection with Low Sporadic Overhead and Communication Locality

A system for spraying fluidized powder circumferentially around a pipe comprising a powder applicator ring engageable with a pipe and having a pair of powder dispensers mounted thereon, a powder fluidization chamber containing a quantity of powder therein, a hose for introducing a stream of air into the chamber to fluidize the powder therein, a powder recovery canister having a pair of axially opposed powder blowers mounted thereon which have their intakes in communication with the interior of the 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 the canister, a pair of powder control valves connected to the chamber and in communication with the fluidized powder therein, a rod for actuating the powder control valves wherein a quantity of fluidized powder is exhausted into an orifice in each powder control valve, a hose for introducing the fluidized powder from each powder control valve into the sides of each powder blower outlet, a conduit connecting each powder blower outlet with a portion of each powder dispenser for supplying a stream of fluidized powder, a return conduit connecting each tangential inlet pipe to another portion of each dispenser for returning excess powder to the canister, and a fluidization blower mounted on the cylinder from which a stream of fluidizing air is allowed to pass.