Tank`s e.g. hydrocarbon tank, liquid level measurement device for hydrocarbon transport field, has face blocking translation of piston contacting liquid, in position corresponding to data scaling position visible from exterior of tank

摘要

The device has a valve head (40) placed near a tubular unit (42) for trapping liquid in the unit (42). A piston has a truncated face (52) allowing the displacement in translation of the piston towards the trapped liquid . The face blocks the translation of the piston, when it contacts the liquid. The blocked piston position corresponds to a data scaling position with respect to an upper wall (12) of a liquid tank. The data scaling position is visible from the exterior of the tank.