Abstract: The present invention provides a composite pressure vessel containing a distributor plate. The distributor plate comprises a thermoplastic polymeric disk having a top side, a bottom side, a perimeter edge and a central opening. The disk is provided with a plurality of radial slits, which define fluid flow passages through the disk between the central opening and the perimeter edge. The fluid flow passages through the disk are adapted to swirl fluid flowing through the disk from the bottom side to the top side such that it swirls around the central opening. The perimeter edge of the distributor plate is joined to an inner side of a thermoplastic liner during or immediately after the thermoplastic liner is formed by a blow-molding process or a rotational molding process.

Abstract: The present invention provides a flow-control support for a distributor plate in a composite pressure vessel. The distributor plate includes a thermoplastic polymeric disk having a top side, a bottom side, a perimeter edge and a central opening and a plurality of fluid flow passages through the disk. The flow-control support is disposed between the bottom side of the disk and an inner side of an end of a thermoplastic liner assembly. The flow-control support includes a spirally fluted upper surface that is adapted to direct fluid flowing from a supply pipe disposed in the central opening of a distributor plate that is supported by the flow control support such that the fluid swirls in a space between the bottom side of the distributor plate and an inner side of an end portion of a water treatment vessel. The swirling water insures that fluid is distributed to substantially all of the fluid flow passages through the disk during backwashing operations.

Abstract: The present invention provides: a distributor plate for a composite pressure vessel. The distributor plate includes a thermoplastic polymeric disk having a top side, a bottom side, a perimeter edge and a central opening. Radial slits are formed in the disk to define fluid flow passages through the disk between the central opening and the perimeter edge. The fluid flow passages through the disk are adapted to swirl fluid flowing through the disk from the bottom side to the top side around the central opening. The present invention also provides a water treatment vessel that includes one or more distributor plates, a method for manufacturing a composite pressure vessel that includes one or more of the distributor plates and a method for preparing a composite pressure vessel that includes one or more of the distributor plate for use as a water treatment apparatus.