Reverse osmosis is a well-known process for the separation of solvent from a solvent-solute solution. The process utilizes a semipermeable membrane and high pressures to selectively diffuse solvent molecules through the membrane resulting in separation of pure solvent from the solvent-solute solution.
Reverse osmosis systems typically utilize a cylindrical filter having walls formed from a semipermeable membrane material. A solvent-solute solution, from which pure solvent is to be removed, is contacted with the outer circumferential membrane wall of the filter. Upon application of sufficient pressure to the solution and filter exterior, i.e. typically at least about 100 psi and often from about 500 psi to about 1500 psi, solution is driven toward the interior of the filter. Pure solvent is then typically collected from the ends of the filter.
Filter housings are provided for containing reverse osmosis filters. The housings are commonly formed from steel in view of the relatively high pressures existing within the housing during separation. As will be appreciated, steel housings are expensive and so have to some extent, limited the applicability and use of reverse osmosis systems.
Plastic filter housings have been introduced which although satisfactory in many respects, still present several significant drawbacks. Currently available plastic filter housings for reverse osmosis filters utilize end caps that are bonded or otherwise affixed to the filter housing. Such attachment renders accessing the interior of the housing exceedingly difficult. Even if an end cap is successfully removed without damaging the cap or housing, such as to replace a filter cartridge, the end cap must then be re-attached. Re-attached end caps are often susceptible to failure upon pressurization of the filter housing. Thus, there is a need for an improved end cap assembly that enables ready removal of an end cap and secure re-attachment thereof to a plastic filter housing, without a loss in the integrity of the housing upon reassembly.
Another drawback to currently known filter housings, metal or plastic, is the limited degree of installation flexibility. That is, except for custom designed housings and systems which are typically relatively expensive, commercially available housings are available in only a limited number of connection configurations. Thus, it would be desirable to provide a filter housing with an increased number of connection configurations.