Provided is an ultrafine bubble generating method and an ultrafine bubble generating apparatus capable of efficiently generating a UFB-containing liquid with high purity. To this end, a flow passage inner volume is varied by using a flow passage inner volume varying element, the liquid is pressurized such that the liquid passes through a narrow portion at high speed and flows into a depressurizing area.

Provided is a UFB-containing liquid production apparatus that can efficiently produce a UFB-containing liquid with a UFB generation unit. The UFB-containing liquid production apparatus includes: a gas dissolution unit that produces a gas-dissolved liquid by dissolving a gas into a liquid supplied from a liquid supply unit; a UFB generation unit that generates UFBs in the flowing-in gas-dissolved liquid; and a circulation path that supplies the gas-dissolved liquid to the UFB generation unit and supplies a UFB-containing liquid produced by the UFB generation unit to the liquid supply unit. In the circulation path, there is provided a micro-bubble reduction unit that reduces an amount of micro-bubbles contained in the gas-dissolved liquid to flow into the UFB generation unit.

An object of the present disclosure is to improve the generation efficiency of a UFB-contained liquid in a generation apparatus having a circulation mechanism. One embodiment of the present invention is an ultra fine bubble generation apparatus including: a first tank that stores a liquid; a generation unit configured to generate an ultra fine bubble in the liquid output from the first tank; a second tank that stores the liquid output from the generation unit; and a liquid passage that inputs again the liquid stored in the second tank to the first tank, and the ultra fine bubble generation apparatus includes a blocking configuration that blocks an ultra fine bubble included in the stored liquid from being input again to the first tank.

A mixing apparatus for generating and mixing gas bubbles into an aqueous solution includes a structure defining an interior fluid-flow chamber that extends along a longitudinal axis between an input port at a liquid input end and an output port at a liquid output end. The structure includes a gas injection portion located upstream from the liquid output end and a mixing vane portion extending in the downstream direction from the gas injection portion. The gas injection portion defines a gas injection lumen and a first region of the interior fluid-flow chamber, while the mixing vane portion defines a second region of the interior fluid-flow chamber. The first region of the interior fluid-flow chamber includes a plurality of side fluid-path lumens that extend alongside a first part of the gas injection lumen. This first part of the gas injection lumen and the side fluid-path lumens merge with a downstream fluid-path lumen of the first region.

Provided is a method of producing an ultrafine bubble-containing liquid containing ultrafine bubbles generated by causing film boiling in a liquid with a heat generation member, including: detaching a solid present at a liquid contact surface of the heat generation member in a form of a microscopic substance by using the film boiling; and generating ultrafine bubbles with the detached microscopic substance as a core.

Provided is a ultrafine bubble generating apparatus capable, when generating nanobubbles in a liquid, of appropriately mixing a gas into a liquid ejected from a liquid ejector. The ultrafine bubble generating apparatus comprises a liquid ejector for ejecting a liquid, a gas mixer for pressurizing and mixing a gas into the liquid ejected from the liquid ejector, and an ultrafine bubble generator for generating nanobubbles in the liquid by passing the liquid with intermixed gas therethrough. Between the liquid ejector and the ultrafine bubble generator, the gas mixer pressurizes and mixes the gas into the liquid, which is flowing in a pressurized state toward the ultrafine bubble generator.

A method is provided for producing fine-bubble water by resonance foaming and vacuum cavitation, and a device for manufacturing each of ultra-fine-bubble water of hydrogen gas having a reducing radical function, ultra-fine-bubble water of air and oxygen gas having an oxidizing radical function, ozone ultra-fine-bubble water having a sterilization function enabled by ozone, and fine-bubble water of nitrogen/carbon dioxide gas for increasing the ability to preserve the freshness of raw agricultural products, livestock products, and marine products.

Provided are: a microbubble generation device utilizing a swirling flow generated by injecting of a pressurized liquid; a microbubble generation method capable of generating a large amount of bubbles; and a shower apparatus and an oil-water separation apparatus having said microbubble generation device. This microbubble generation device comprises: a cylindrical or conical cylinder with a gas-liquid swirling chamber therein; a gas-liquid discharge inlet provided on one end of the cylindrical or conical cylinder; and a liquid supply cylinder and a gas supply cylinder for introducing a liquid and a gas into the gas-liquid swirling chamber. For the gas-liquid discharge outlet, a plurality of small cylindrical through-holes or a plurality of small recessed parts with a circular cross-section and at least a semicircular circumferential length, are respectively provided in the wall of a closed end at one end of the cylindrical or conical cylinder or on the circumferential surface of the inner wall of an open end at one end thereof.

Provided is a liquid supply apparatus which is capable of directly taking in a liquid from a flow channel and appropriately mixing a gas into the liquid when generating-nanobubbles in the liquid using an ultrafine bubble generating apparatus. The liquid supply apparatus comprises a flow channel for a liquid supplied from a liquid supply source and an ultrafine bubble generating apparatus for generating nanobubbles in the liquid. The ultrafine bubble generating apparatus is provided with: a liquid ejector for ejecting the liquid taken in from the flow channel; a gas mixer for pressurizing and mixing a gas into the liquid ejected from the liquid ejector; and a nanobubble-generating nozzle for generating nanobubbles in the liquid by passing the liquid with intermixed gas therethrough. The pressure of the liquid in the flow channel flowing into the liquid ejector from the upstream-side of the liquid ejector is a positive pressure and, between the liquid ejector and the-nanobubble-generating nozzle, the gas mixer pressurizes and mixes the gas into the liquid, which is flowing in a pressurized state toward the nanobubble-generating nozzle.

In order to efficiently produce a liquid containing ultrafine bubbles of a desired gas, an ultrafine bubble-containing liquid producing apparatus includes a gas dissolving unit that dissolves a predetermined gas into a liquid, and a UFB generating unit that generates ultrafine bubbles in the liquid in which the predetermined gas is dissolved. A CPU performs control under a first condition in a case of causing the gas dissolving unit to operate in a circulation route passing through the dissolving unit. The CPU performs control under a second condition different from the first condition in a case of causing the UFB generating unit to operate in a circulation route passing through the UFB generating unit.