Abstract: The water purifier is operated entirely automatically and hydraulically in response to the opening and closing of the outlet valve from which pure water is drawn. All of the passageways and control valves are contained within a unitary body so that there are no external hoses and fittings. The only connections to the body are a pure water outlet, a waste water outlet and the water inlet. In the filter chamber a reverse-osmosis filter membrane is circumscribed by a brine seal at the same end portion as where the pure water is discharged. All water passageway connections are made at that end of the filter chamber, so that the other end can be unthreaded for removal and replacement of the filter membrane without disconnecting water lines. An improved pilot valve within the unit has a tapered end portion engaging an O-ring seat held in place by a spring-pressed washer.

Abstract: An apparatus and method whereby after a reverse-osmosis water purifier system has been shut down, the first quantity of water, which emanates from the reverse-osmosis filter, does not flow through the pure water storage tank but instead to the drain. Therefore, the water in the reverse-osmosis filter, and which has become contaminated as the result of standing in the filter so that a substantial amount of osmosis can occur, does not contaminate the pure water in the storage tank or system but instead is discarded.

Abstract: An economical and commercially practical reverse-osmosis water purifier system which has no back pressure acting against the semipermeable membrane, so that the filtering rate is maximized. Furthermore, the supply of tap water to the system is shut off automatically as soon as the pure water storage tank is full, use of water thus being greatly reduced. These, and other major advantages, are achieved despite the fact that there is only a single tube extending to the faucet, automatic ice-maker, refrigerated drinking fountain or other point of use.The system uses rugged, long-lasting and economical diaphragm valves, which eliminates the need for sliding seals. Thus, it becomes highly practical to injection-mold the valves of plastic.The long-standing major problem of plugging or fouling of the constricted outlet for waste water is eliminated at low cost and with very little use of water. What water is used provides not only cleaning of the constriction region but also a partial flushing of the filter membrane.

Abstract: This invention provides an arrangement for delivering purified water on demand, which includes a reverse osmosis filter having an inlet for connection to a source of pressurized water, and a purified water outlet connected to a tank where the purified water enters a bladder. Unpurified water from the filter is connected to the tank on the outside of the bladder for forcing purified water through a purified water outlet. This connection also includes a restricted passageway to a drain. A second discharge for unpurified water from the reverse osmosis filter connects through another restrictor to the drain. The system is controlled by an actuator which operates a valve to control the flow of unpurified water, thereby causing the same to force purified water from the tank to the purified water outlet, and a valve for controlling the flow of inlet water to the reverse osmosis filter, shutting off such flow when the tank is filled with purified water.