Abstract: In order to eliminate bubbles in a liquid, the liquid is introduced into a flow passage having circular cross section as tangential flow which turns into swirl flow circulating around axis along the shape of the flow passage and that accelerates and decreases the pressure of the swirl axis and collects bubbles at the portion where pressure becomes lowest, and discharges the collected bubbles through a vent hole or a small vent pipe.

Abstract: A liquid is introduced tangentially into a cylindrical body through a plurality of equiangularly spaced inlet ports disposed on the cylindrical body adjacent to a closed end thereof. Thus, the liquid is swirled in the cylindrical body and bubbles in the liquid are collected, by means of the centrifugal force in the swirl flow, toward the axis of the cylindrical body at the inflow side and are removed.

Abstract: In order to prevent bubbles collected by a bubble collecting device from flowing again into a fluid, the bubbles are positively discharged from a bubble collecting zone and directed to an upper portion in a liquid container so that even when the fluid is discharged together with the bubbles, such discharged fluid is positively recovered in the fluid vessel.

Abstract: Disclosed is a method for causing bubbles in a fluid to coalesce into a coherent mass by use of a vessel having a cylindrical space therein wherein the fluid is caused to flow into the vessel at such a velocity that a vortex is generated to flow from one end of the space to the other while establishing a state in which the pressure on the center axis of the cylinder rises from one end toward the other, then reaches a maximal value and thereafter drops, and this coalescing of the bubbles is effected at the field near the axis of the vortex and between a position close to the inflow position and the position of the highest pressure. The method greatly facilitates deaeration.

Abstract: A tank for storing a liquid is provided with a circulation passage for circulating the liquid by a suction pump. A pressure at the suction port of the suction pump is maintained at a negative pressure lower than a pressure at which gases dissolved in the liquid and the liquid is circulated, whereby the gases having been dissolved in the liquid are separated and the bubbles entrained by the liquid grow in size. These gases and bubbles are collected, agglomerated and discharged in the line connected to the discharge port of the suction pump.

Abstract: In a closed discharge chamber wherein a discharge electrode supported on an electric insulating material and an opposite electrode are arranged to confront each other, a high electric potential applied between said electrodes causes corona discharge to occur in the gas between the two electrodes. A method for control of pure fluid elements, fluid servomechanisms, etc. is disclosed which is accomplished by utilizing a phenomenon that the pressure of the gas within the closed discharge chamber increases in consequence of the occurrence of corona discharge and the increased pressure falls with the subsequent extinction of corona discharge back to the level existing before said corona discharge.

Abstract: In cooling an article by the phenomenon of corona discharge caused when the article is placed opposite a high-potential electrode, a high electric potential is applied between the article and the electrode. This invention contemplates interposing a corona focusing ring between the article and the high-potential electrode. When high electric potential is also applied to the corona focusing ring, the avalanche of ions generated by the electrode in consequence of corona discharge is focused upon the article by the corona focusing ring, with the result that local cooling is effected on the article.