a process and apparatus for the separation of gas bubbles from a liquid which is subjected to a flow , in which a flowing portion of the liquid is brought into contact with an arcuate wall at an opening and deflected into a relatively quiescent liquid along a surface , so as to produce a vortex at the contact surface between the two liquid portions in such a manner as to project the vortex into the flowing portion as well as into the relatively quiescent portion , and whereby its axis extends in parallel or almost parallel to the contact surface , so that gas bubbles will be conducted from the flowing liquid portion by the vortex into the relatively quiescent liquid portion , from which the gas bubbles will then separate out under the influence of buoyant force .