Abstract: Compound filters using two different filter element types are disclosed. When a carbon element is used it is of the concentric type having a central cavity. Filter elements for filtering very fine particles are used in addition. Various types of such elements, including hollow fiber elements, are disposed in a lower portion and/or upper portion. Flow control arrangements, improved filter element removal arrangements, improved filter sealing arrangements, accommodations for filter elements having different lengths and tolerances and filter arrangements for preventing liquid flow when no filter element is present are described.

Abstract: A water purification system has a longitudinal ultraviolet tube, an arrangement of helically-wound coils surrounding the tube and a filter. Water is exposed to ultraviolet energy before and after flowing through the filter. The filter, ultraviolet tube and helically wound coils are all arranged within a unitary housing adapted for kitchen countertop, sink backsplash or under wall cabinet mounting. The system is capable of operatng directly from a kitchen sink faucet. Connecting elements for the coils are specially designed to be leak-proof. A closed, reflective chamber surrounds the ultraviolet arrangement.

Abstract: A fluid purification system includes an elongated ultraviolet radiation emitting tube and independent fluid flow-controlling conduits. Each conduit is transparent to allow ultraviolet light emitted by the tube to enter the conduit, and defines a continuous path, and is helically wound closely about the tube to insure that fluid flow through the conduits is exposed to the ultraviolet light. One embodiment of the system includes a filter typically a carbon filter, having inlet and outlet ports. An end of each conduit is connected to one of the inlet and outlet ports of the filter. The system thus exposes the fluid to ultraviolet radiation both before and after the fluid is filtered. Other embodiments include reverse osmosis units and deionization units wherein each entry, exit or discharge port is isolated from contamination by having a coiled connecting tube for the fluid exposed to ultraviolet radiation.

Abstract: A fluid purification system includes an elongated ultraviolet radiation emitting tube and independent fluid flow-controlling conduits. Each conduit is transparent to allow ultraviolet light emitted by the tube to enter the conduit, and defines a continuous, and is helically wound closely about the tube to insure that fluid flow through the conduits is exposed to the ultraviolet light. The system includes a filter having inlet and outlet ports. An end of each conduit is connected to one of the inlet and outlet ports of the filter. The system thus exposes the fluid to ultraviolet radiation both before and after the fluid is filtered.