[en] The liquid is distributed to the rotary cylinder from the cylindrical inlet chamber. Into the cylindrical chamber the liquid is fed radially relative to the rotary cylinder. The outlet tube for the liquid or for one of its two phases is inside the rotary cylinder and is coaxial with it. The inlet cross sections of the rotary cylinder are evenly distributed along the whole contact area between the rotary cylinder and the cylindrical inlet chamber, or they occupy the whole contact area. The equipment consists of a right-hand helical surface and a left-hand helical surface, coaxial with the rotary cylinder and the cylindrical inlet chamber with each of the two helical surfaces having a maximum central angle of 180deg. Their common surface straight line closest to the contact area lies on that side of the outlet tube which is opposite to the inlet pipe, in the radial plane of symmetry of the cylindrical inlet chamber passing through the supply pipe. (B.S.)