The rotating valves have been designed for being used on rotative tables with poly-flange devices.
All around this table, work stations are facing a clamping device.
(Drawing below).

On the loading / unloading station, the machined piece is removed and replaced by a new piece.
The rotating valve placed on the center of one station without modifying the working hydraulic pressure of the other stations.

The choice of the rotating valve depends of the number of the work stations on the rotative table and the type of cylinder used : Single acting cylinder or double acting cylinder.

The possible number of stations is from 2 up to +.