3578167 is referenced by 6 patents and cites 2 patents.

A pair of water conditioning tanks each having a service port. The service ports are connected to each other and to a service outlet conduit. A pair of semibalanced, direct-acting control valves are provided, each having an inlet port, a tank port connected to one of the conditioning tanks, and a drain port. Each valve has a pressure responsive piston engaging the valve stem and a conduit for supplying line pressure to the piston to assist in operating the valve. Timed motor operators alternately maintain one of the valves in service position and the other in backwash position whereby each tank can be backwashed with conditioned water from the other.

Multiple-tank water conditioning system and valve therefor
Application Number
Publication Number
Application Date
October 19, 1968
Publication Date
May 11, 1971
Nygren Charles E
Kay Clifford
Clack Willis E
Clack Corporation
B01d 29/08
B01D 35/00
B01D 35/12
B01J 47/00
B01J 47/02
C02F 01/42
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