A double liquid distribution device (1) suitable for use in in a fractionating or wash column (10) including a high collector tray (2) connected to a manifold support (7) via at least two longitudinal liquid downflow ducts (5, 6), the manifold support (7) supporting at least two series of transverse tubular manifolds (8, 8a 8b) and serving to feed liquid respectively to the first series of manifolds (8a) via a first longitudinal duct (5) and to the second series of manifolds (8b) via a second longitudinal duct (6), each manifold (8, 8a 8b) including distribution orifices (8c) in its under face that are suitable for distributing the liquid onto the top face of the packing bed (9). The two longitudinal liquid downflow ducts (5, 6) are connected together in a low portion (5b, 6b) by a communication device (11) fitted with a valve (12) having controlled opening that is suitable for allowing the liquid to be transferred between the two longitudinal ducts in a controlled manner.