This invention relates to a control valve for a fluid treatment system, such as a water softener or water filter, which includes a treatment bed that requires periodic backwashing, and particularly to a control valve that is adaptable to control various cycles of operation of the system and various combinations of cycles, including permitting a selection of co-current or countercurrent operation, and either allowing or preventing untreated fluid to pass to service lines during backwash or regeneration.
Filter beds require periodic backwashing. The control of the backwashing is usually accomplished by valving which is responsive to a timer that calls for the backwashing under predetermined conditions or at predetermined time intervals. Backwash is often followed by a rinse cycle which is controlled by the same valving.
Both water softener resin beds and regenerable filter beds also require periodic backwashing as well as the periodic introduction of a regenerative fluid, such as brine or potassium permanganate, to the bed. Rinsing cycles are also typically involved in the backwashing and regeneration. The backwash, rinse, and regeneration cycles are again typically controlled by valving that is actuated by a motor controlled by a timer and often responsive to the volume of usage to which the bed has been subjected since the last regeneration. In a water softener, the valving is typically mounted on the top of a tank that contains the resin bed. A tube extends downwardly through the bed and is in fluid communication with the bottom of the bed. The valving communicates with the top of the resin bed and with the bottom of the resin bed via the tube so that various fluids can be passed down through the bed, and up through the bed.
Regeneration of a water softener resin bed is sometimes accomplished in a direction that is co-current with the flow of water to be treated and is sometimes accomplished in a direction that is countercurrent to the flow of water being treated. Also, some water softener valving is arranged to allow the passage of untreated water to the service lines during backwash, rinse, and regeneration, while other softener valving is arranged to block the flow of untreated water to the service line during such cycles.
It is a principal object of the invention to provide a control valve that is adaptable to control the relatively simple cycles of service, backwash, and rinse in a filter bed and which is also adaptable to controlling the more complex cycles required for a bed that needs to be regenerated.
It is also an object of the invention to provide such an adaptable control valve which can alternately regenerate co-current with the flow of treated fluid and countercurrent with such flow.
It is another object to provide such a control valve that can alternately allow untreated fluid to flow to service lines during backwash and/or regeneration and to block such flow.