Patent ID: 6868795

Claim:
A bubble cap assembly for supplying a fluidizing medium into a fluidized bed of granulated material, comprising: a stem having two ends, wherein one end is inserted into a bubble cap with a gap therebetween, the inserted end having at least one of a circular groove and an indentation on its outer surface, the bubble cap having at least one outlet hole for delivering the fluidizing medium into the bed of granulated material and having at least one insertion hole which is adjacent to at least one of the circular groove and the indentation on the stem when the bubble cap receives the inserted end of the stem; and at least one pin inserted into the insertion hole and engaged with at least one of the circular groove and the indentation on the stem for coupling the bubble cap to the stem, sizes and tolerances of the inserted end of the stem, an inside diameter portion of the bubble cap receiving the stem, and of the at least one pin and insertion hole being selected to allow for unobstructed thermal expansion during operation while minimizing fluid leakage through the gap.