Liquid-treatment system

Claim 1

A liquid-treatment system made of modular elements for treating liquids such as water comprising; a first tank having a liquid-treatment cartridge therein for treating all of a liquid received for treatment; a second tank constructed similarly to the first tank without a cartridge for receiving the liquid treated in said first tank; a modular liquid-control unit for controlling flow of liquid into said first tank to be treated and flow of liquid from said first tank to said second tank and outflow of treated liquid from said second tank comprising, two similar modular couplings symmetrically mounted and each removably connected to the interior of a corresponding one of said first tank and said second tank, a mounting element fixedly mounting said modular couplings relative to each other thereon for mounting and for removal of said liquid-control unit as an assembly with respect to the two tanks, mounting elements on said modular couplings for mounting thereof removably on the corresponding tanks, each modular coupling having two independent coaxial flow paths comprising an inner and an outer flow path, a removable connecting conduit connecting the outer flow paths of the modular couplings, a supply valve mounted on said mounting element connectable in use to a supply main for supplying liquid to be treated and having a valve element for turning on and off flow of liquid into said liquid-control unit, a flow-control device in series with said supply valve for controlling the flow of liquid from said supply valve at a substantially constant flow at a pressure tolerable by the liquid-treatment system in the presence of pressure variations in the supply main and for precluding water-hammering in the system, at least one electromagnetically-controlled valve closed when deenergized mounted on and upstream of the modular coupling mounted on said first tank and downstream of said flow-control device for supply of liquid therethrough to the inner flow path of said modular coupling on said first tank for flow through said liquid-treatment cartridge, a pair of similar microswitches on said fluid-control unit comprising a first microswitch for controlling application of an electrical signal to said electromagnetically-controlled valve for opening for allowing flow of liquid into said first tank in dependence upon the water level in said second tank to render said first microswitch effective to apply said signal when said liquid in said second tank is below said predetermined level; means for rendering the second of said microswitches effective to control the outflow of liquid from said second tank through the inner flow path of said second modular coupling; said second tank having one-way means above said predetermined level for venting it to the atmosphere; and one-way means on said second tank for allowing entry of filtered air thereinto as the level of said second tank varies downwardly.