The present invention provides a fine bubble generating apparatus capable of generating fine bubbles efficiently. The present invention includes a fluid flow passage that includes a narrow portion in at least a part thereof, a heating part capable of heating a liquid flowing through the fluid flow passage, and a controlling unit that controls the heating part. The controlling unit controls the heating part to generate film boiling in the liquid to generate ultrafine bubbles.

Ultrafine bubbles with a diameter of less than 1.0 m are generated in liquid by causing film boiling in liquid by means of a heater.

A microbubble generator is formed from at least two of a flow path constituting section that constitutes a flow path through which a liquid is passable, and a decompression member including a colliding section that is fitted into the flow path constituting section and locally reduces a cross-sectional area of the flow path to generate microbubbles in the liquid that passes through the flow path. This microbubble generator comprises includes an outlet connecting to a negative pressure producing section of the decompression member, an outside air introduction port provided in the flow path constituting section to introduce outside air, and an outside air introduction path communicating between the outside air introduction port and the outlet.

An apparatus for producing a composition that includes nano-bubbles dispersed in a liquid carrier includes: (a) an elongate housing comprising a first end and a second end, the housing defining a liquid inlet, a liquid outlet, and an interior cavity adapted for receiving the liquid carrier from a liquid source; and (b) a gas-permeable member at least partially disposed within the interior cavity of the housing. The gas-permeable member includes an open end adapted for receiving a pressurized gas from a gas source, a closed end, and a porous sidewall extending between the open and closed ends having a mean pore size no greater than 1.0 m. The gas-permeable member defines an inner surface, an outer surface, and a lumen. The housing and gas-permeable member are configured to form a composition that includes the liquid carrier and the nano-bubbles dispersed therein.

A nanobubbler includes a porous ceramic material, a first inlet configured to inject a gas into the porous ceramic material, wherein the porous ceramic material is configured to emit nanobubbles into the chamber from the surface in response to the injection of the gas, a chamber positioned adjacent to a surface of the porous ceramic material, a second inlet configured to inject a liquid into the chamber so that the nanobubbles are dislodged from the surface of the porous ceramic material into the liquid, and an outlet configured to output from the chamber the liquid infused with the nanobubbles. The nanobubbles infused into the liquid have an average diameter of less than 500 nanometers.

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.

A nanobubble-producing apparatus includes a liquid vat provided with a bubble-containing-liquid inlet in an upper part thereof and a bubble-containing-liquid outlet in a bottom part thereof, a microbubble-containing-liquid supply unit to supply microbubble-containing liquid that contains microbubbles to the bubble-containing-liquid inlet of the liquid vat, an ultrasonic collapse unit to radiate ultrasonic waves to the inside of the liquid vat so that an ultrasonic collapse field in which the collapsing of the microbubbles with the ultrasonic waves is concentrated and nanobubbles are generated is formed at a location where the microbubble-containing liquid supplied into the liquid vat through the bubble-containing-liquid inlet flows downward, and a nanobubble-containing-liquid extraction portion where the nanobubble-containing liquid that contains the nanobubbles generated by the ultrasonic collapse unit is taken out of the liquid vat through the bubble-containing-liquid outlet.

An apparatus for producing a composition that includes nano-bubbles dispersed in a liquid carrier includes: (a) an elongate housing comprising a first end and a second end, the housing defining a liquid inlet, a liquid outlet, and an interior cavity adapted for receiving the liquid carrier from a liquid source; and (b) a gas-permeable member at least partially disposed within the interior cavity of the housing. The gas-permeable member includes an open end adapted for receiving a pressurized gas from a gas source, a closed end, and a porous sidewall extending between the open and closed ends having a mean pore size no greater than 1.0 m. The gas-permeable member defines an inner surface, an outer surface, and a lumen. The housing and gas-permeable member are configured to form a composition that includes the liquid carrier and the nano-bubbles dispersed therein.

An apparatus for producing a composition that includes nano-bubbles dispersed in a liquid carrier includes: (a) an elongate housing comprising a first end and a second end, the housing defining a liquid inlet, a liquid outlet, and an interior cavity adapted for receiving the liquid carrier from a liquid source; and (b) a gas-permeable member at least partially disposed within the interior cavity of the housing. The gas-permeable member includes an open end adapted for receiving a pressurized gas from a gas source, a closed end, and a porous sidewall extending between the open and closed ends having a mean pore size no greater than 1.0 m. The gas-permeable member defines an inner surface, an outer surface, and a lumen. The housing and gas-permeable member are configured to form a composition that includes the liquid carrier and the nano-bubbles dispersed therein.

A system for stabilizing gas-infused liquid, includes a tubular flow path configured to receive and pass therethrough the gas-infused liquid under a pressure of at least 20 psi, wherein a surface of the flow path configured to engage the gas-infused liquid flowing through the flow path is formed of material having a surface roughness (Ra) in a range of 0.1 m-10.0 m, and the flow path has a length which is at least 100 times a mean inner diameter thereof.