Abstract: A normally open non-electric valve includes a flow path through an apertured valve seat . . . cavity isolated from the flow path is sealingly closed off adjacent the valve seat by a flexible diaphragm. The diaphragm is sufficiently flexible to be pushed and held away from the valve seat by fluid flowing in the flow path. When it is desired to close the valve, a pressure medium is introduced into the cavity so as to force the diaphragm against the valve seat and interrupt the fluid flow in the flow path. The normally open valve can inexpensively be converted from an inexpensive electric solenoid valve by removing the plunger, spring and coil from the electric valve, closing off the plunger cavity with a flexible diaphragm, and selectably introducing a pressure medium into the cavity when it is desired to close the valve.

Abstract: A method and corresponding apparatus employ purified water to backflush a filtration device. Purified water includes water having a total dissolved solids reading less than that of the water being filtered. Examples of purified water may include water treated using reverse osmosis, steam distillation, or deionization processes, and the like. In the simplest form, the purified water is used to rinse or backflush a filter or filter cartridge. Further extensions include valves to switch from a primary flowpath used for normal operations to a secondary flowpath used to conduct backflushing routines. Backflushing routines may be initiated on demand or through an automated routine that repeats the process on a regular basis.