Abstract: A liquid purification system is disclosed. In this system water is pumped into a filter cartridge. A reverse osmosis filter membrane in the filter cartridge removes impurities from the water, but not all of the water passes through the membrane. Water passing through the membrane exits the filter cartridge through a first outlet port, and is sent to a storage tank. Water not passing through the filter membrane exits the filter cartridge through a second outlet port. This water then passes through a pressure relief valve. The pressure relief valve can be adjusted to vary the water pressure and flow rates in the system. Some of the water exiting the pressure relief valve passes through a flow restrictor valve and then to drain. The flow restrictor maintains a constant flow rate at variable pressures. In this system, the flow restrictor is operable to maintain the same flow rate through it to drain and through the first filter outlet port.

Abstract: An improved multi-port connection device (10) adapted to receive prior art membrane and filter canisters (12) and to make connections between plural connection devices more convenient and versatile, comprising a plurality of flow ports (43,45,47) which are all at a common level, two of which communicate through apertures (52,54) in a barrier wall (55) forming a female connector with input and output flow paths (18,16) in the canister male connector, said apertures (52,54) being positioned in the barrier wall (55) on separate sides of an O-ring seal at locations communicating with the input and output flow paths (18,16).

Abstract: A fluid treatment system is provided which includes a fluid distribution manifold, a multiport connector including a plurality of fluid channels, and at least one discrete fluid treatment cartridge. The distribution manifold includes a plurality of fluid channels, one for each of a plurality of fluid connection tubes with the fluid channels having inlet and outlet ports. The multiport connector is configured such that each one of the fluid channels in the multiport connector aligns with one of the ports in the distribution manifold. The fluid treatment cartridge includes a sump which includes a fluid inlet port and a fluid outlet port. The sump is configured such that the cartridge fluid inlet port aligns with one of the ports in the distribution manifold and the cartridge outlet port aligns with another the ports in the distribution manifold. A replacement treatment cartridge is also provided for a distribution manifold which includes a cartridge receiving aperture.

Abstract: A flow restrictor that is intended primarily for use in a reverse osmosis water purification system of the type having a reverse osmosis membrane housing receiving feed water to be purified and generating purified water at a first outlet and waste water at a second outlet. The flow restrictor of the invention comprises a selected length of elongated, doubly-extruded tubing having an inner, low-friction tube and an outer, higher-friction tube. The outer tube is coaxial with the inner tube and has an inner surface which is substantially contiguous with the outer surface of the inner tube. The diameter of the inner tube and the length of the tubing are selected for precisely limiting flow of water therethrough.