Fluidized bed top surface stabilization mechanism

Claim 1

In a method of coating an article by means of a fluidized bed coating technique wherein a fluidization chamber is utilized having impervious side walls, a gas pervious distributor plate adapted to support a bed of pulverulent coating materials, an open top, and having means for passing fluidizing gases upwardly through said gas distributor plate to fluidize said pulverulent materials, the improvement comprising: a. providing a generally horizontally disposed means of a generally perforate configuration and including at least one enlarged opening therein of sufficient size to accommodate the passage of an article therethrough for total or partial immersion in said fluidized bed, b. positioning said horizontally disposed means and controlling the pulverulent coating materials and the fluidizing gases in a manner such that said horizontally disposed means will engage only the upper most surface of the fluidized pulverulent coating materials, said horizontally disposed means and said pulverulent coating materials being below the top of the impervious side walls of said fluidization chamber, c. emersing an article in said fluidized bed by inserting it through said enlarged opening for a time sufficient to coat said article and then withdrawing it from said opening.