Nanobubble-producing apparatus

A nanobubble-producing apparatus comprising:

• a liquid vat provided with a bubble-containing-liquid inlet and a bubble-containing-liquid outlet;
• 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 an 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;
• and
• a nanobubble-containing-liquid extraction portion where 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,
• wherein the ultrasonic collapse unit includes a plurality of an ultrasonic oscillators that are able to emit the ultrasonic waves,
• wherein the liquid vat includes:
• an outer receptacle to which the plurality of ultrasonic oscillators are fixed and radially arranged in a plan view;
• and
• an inner receptacle that is formed inside the outer receptacle, the inner receptacle being provided with the bubble-containing-liquid inlet and the bubble-containing-liquid outlet,
• wherein a medium-liquid retention area for storing medium liquid to propagate the ultrasonic waves to the inner receptacle is formed between the outer receptacle and the inner receptacle, and
• wherein the microbubble-containing-liquid supply unit includes:
• a gas-liquid mixer to mix liquid with gas;
• a microbubble generator that makes the microbubble-containing-liquid of the liquid mixed with the gas by the gas-liquid mixer;
• and
• a pump acting to discharge the microbubble-containing-liquid into the bubble-containing-liquid inlet.