Water softener control valve with removable seal stack

A water treatment system control valve comprising:

• (A) a valve body which has (1) an internal bore, (2) external ports configured for connection to at least a source of untreated water, a treated water outlet, a brine line, a drain, and a resin tank, respectively, (3) a plurality of internal ports opening into said internal bore, and (4) a plurality of passages connecting various ones of said internal ports to various ones of said external ports;
• (B) a piston which is axially slidable in said bore under the action of a controller to connect various ones of said internal ports to one another in combinations that vary depending upon the position of said valve piston in said bore;
• and
• (C) a seal stack which is disposed in said bore and which surrounds said piston, said seal stack including a plurality of elastomeric static seals which seal against a peripheral surface of said bore and a plurality of dynamic seals which are disposed radially inwardly of said static seals and which seal against said piston, wherein said seal stack is dimensioned and configured such that (1) said seal stack is compressible axially upon valve assembly to expand said static seals radially to enhance sealing contact between said static seals and said peripheral surface of said bore, and (2) upon initial removal of said seal stack axially from said bore, said seal stack expands axially to permit said static seals to constrict radially to diminish sealing contact between said static seals and said peripheral surface of said bore, thereby releasing said static seals from said peripheral surface of said bore and facilitating further removal of said seal stack from said bore.

A water treatment system comprising:

• (A) a brine tank;
• (B) a resin tank containing a treatment medium;
• and
• (C) a water softener control valve including
• (1) a valve body which has (a) an internal bore, (b) external ports configured for connection to a source of untreated water, a service line, said brine tank, a drain, and said resin tank, respectively, (c) a plurality of internal ports opening into said internal bore, and (d) a plurality of passages connecting various ones of said internal ports to various ones of said external ports;
• (2) a piston which is axially slidable in said bore to connect various ones of said internal ports to one another in combinations that vary depending upon the position of said piston in said bore;
• and
• (3) a seal stack which is disposed in said bore and which surrounds said piston, said seal stack including (a) a plurality of spacers, each of which has inner and outer axial ends and inner and outer radial peripheries, (b) a plurality of elastomeric static seals, each of which is disposed between two adjacent spacers and which seals against a peripheral surface of said bore, and (c) a plurality of dynamic seals, each of which is disposed between two adjacent spacers and which seals against said piston, wherein each of said spacers is connected to an adjacent spacer by a lost motion connection that permits limited axial movement therebetween.