The present invention provides a flow apparatus (10) having a flow control valve (12) having a housing (14), an aperture (16), an aperture obturator (18) and an actuator (20) for moving said obturator (16) between a first closed position and multiple open positions (B-L), characterised by a valve position monitor (21) for monitoring the position of the valve (12) and comprising a plurality of discrete sensors (28a to 28e) associated with a plurality of open positions (B-L) of said valve for monitoring the presence or absence of one or more members (26) movable with said valve (12). The arrangement may be used to' monitor the valve position and such monitoring may be of use in the prediction of the amount of fluid remaining within a cylinder (32) to which it has bee attached.