BUBBLING (EN: bubbling, sparging; DE: Barbotage, Druckluftmischung, Durchsprudeln; FR: barbotage; ES: burbujeo; RU: барботирование) is the pressing of the gas through the layer of the liquid. They use it for the heating of the liquid by the vapour, mixing of the aggressive liquids and abrasive slurries; bubbling also accompanies the processes of absorption, rectification, and flotation. There is created during the bubbling the large interface surface at the liquid - gas boundary, which assists to the intensification of the heat and mass exchange processes, and also to the more complete chemical interaction of gases with liquids. The simplest device for the bubbling is the pipe, which is submerged into the reservoir with liquid, through which there is delivered the gas, which is compressed to the needed pressure. In order to avoid the strikes of the jet of gas onto the bottom, the lower end of the pipe is bent. For the more uniform and effective bubbling, they use several horizontally situated pipes, which are having the holes with the diameter of 6.3 millimetres. During the absorption and rectification, the bubbling proceeds on the plates of the so-called bubble columns.