US Patent 10106434 Fluid treatment tank having a distributor plate

A distributor plate for a fluid tank such as a water softener pressure vessel separates the resin bed from a lower end of the resin tank. The distributor plate includes an outer ring that is affixed to the wall of the tank and that is formed of a first thermoplastic material having a relatively low dimensional predictability, and an inner disk that is supported on the outer ring and that is formed from a second thermoplastic material having a relatively high dimensional predictability when compared to that of the first thermoplastic material, the inner disk being fluid permeable but fluid treatment media impermeable. The outer ring and inner disk may be made from high density polyethylene (HDPE) and unfilled or 30% glass-filled Noryl®, respectively. Also disclosed is a method of assembling a pressure vessel.