what is Ultra Fine Bubble

It is an extremely minute bubble in a liquid such as water. These fine bubbles have different names depending on their size. They can be divided into two types: ultra-fine bubbles and micro bubbles. The term “fine bubbles” refers to a condition where there is a mixture of sizes between these two. At present, there are various types of equipment for ultra-fine bubbles and micro bubbles, and bubble properties vary with different generation methods. The innovative technology for creating ultra-fine bubbles comes from Japan. Its scope of application is extremely broad, and it provides new value in many fields, including cleaning, water purification, medicine, and agriculture. The technology has a cross-cutting character with many application in medicine, pharmaceuticals, cosmetics, semiconductors, foods, beverages, agriculture, forestry and fisheries. Going forward, it will be a key industry representing Japan, and it has the potential to become a future-oriented industry with a large worldwide market.

Type of fine bubble

1. Ultra-fine bubbles

Bubble diameter :

Approx. 1 µm or more

Bubble motion :

Extremely slow rise

Bubble observation :

Cannot be visually detected
(transparent water to the naked eye)

2. Microbubbles

Bubble diameter :

Approx. 1–60 µm

Bubble motion :

Brownian motion

Bubble observation :

Can be visually detected

Observation of nanobubbles
using a phase-contrast microscope

It is possible to observe bubbles roughly 12 µm in size at the upper right of the photo at left, and the other white points are bubbles approximately
100–300 nm in size. Cannot be visually detected.

With atmospheric gas, this process from birth to death occurs over a long span of time, lasting about 20 days. Some of the nanosize bubbles in the liquid drift into the atmosphere. (Depending on various conditions.)

Fine bubbles cover a broad range from nanosize to macrosize.
At the time a macrosize bubble is created, gas molecules are vigorously flying around inside the bubble at high density. Therefore, the inside of the bubbles is at high temperature and pressure. A balance is maintained with the interface tension of the liquid, and the bubbles themselves move and do not stay still in the liquid.
[Microsize bubbles grown to nanosize] Bubbles in the liquid undergo heat exchange through the liquid interface. Due to heat exchange with the liquid, the temperature inside the bubbles drops. As temperature drops, the activity of gas molecules gradually loses its vigor, and the pressure of the gas decreases. For this reason, there is a relative strengthening of the interface tension of the surrounding liquid. The bubbles contract due to the condensing force on the bubble, and the particle system is reduced in size. When heat exchange progresses further, the centers of the spherical bubbles are pressed intensively into each other, and before long the bubbles break. The gas molecules inside are dispersed into the liquid, and incorporated into the liquid molecule network, thus becoming a gas-liquid mixture. After that, the necessary gas molecules are left in the gas molecule network, and both the gas molecules and liquid molecules return to their places.

Typical methods

1. Pressurized dissolution

With this method bubbles are produced by releasing, all at once, gas compressed in a liquid. This is a type of high-concentration generation, but many bubbles of 50 µm or larger are produced. There is strong tendency for bubbles to coalesce and grow in size, and bubbles rise quickly. As a result, retention time in the liquid is short.

2. Rotational flow method

With this method, gas and liquid are rotated at high speed, and bubbles are generated through shearing force. Minute, uniform bubbles with negative internal pressure are produced, but at low concentration so production efficiency and testing efficiency are poor.

3. Static mixer method

Same as pressurized dissolution method

4. Cavitation method

Same as rotational flow method

5. Venturi method

Same as rotational flow method

Method of producing products

We continuously and stably produce uniform, high-density fine bubbles. Fine bubbles have almost no buoyancy,
and their retention time increases.
As a result, a state of high-concentration in the liquid can be maintained for a long time.

A. Gas is taken in due to pump negative pressure.
B. Cavitation is produced through shearing, while pressurizing inside the generation mixing header.
C. Bubbles are generated with a bubbling nozzle.

With our company’s system, highly-concentrated, uniform fine bubbles are stably generated by combining the pressurized
dissolution method, rotational flow method, and cavitation method. We have obtained a patent using this method.

1. Surfactant action

Because bubbles have a negative electrical potential, they attach easily to positively charged material such as stains etc. Bubbles are effective for lifting and separating various stains in water, for lessening viscosity through surfactant action which also enables cleaning of industrial products, and for mixing things.

2. Impact pressure action

When bubbles break under pressure, this results in a local high-temperature state, causing impact and acting on the surrounding material.
It is expected that this effect can be widely used in state-of-the-art medicine where cell destruction is needed, as well as in areas such as brewing and fermentation.

3. Bioactivity action

Bubbles have the effect of promoting growth of living organisms, and if oxygen is used as the gas, it is possible to increase the amount of dissolved oxygen with high efficiency. Unlike chemicals, bubbles can contribute to worry-free, safe growth of the body.

4. Bubbles are present in liquid for an extremely long time

UFB are retained in water for a long time, moving in Brownian motion and not floating up to the atmosphere like ordinary bubbles.

 

5. Production of free radicals through bubble breaking

Due to the self-breaking action of bubbles, they cause breakdown of water, nitrogen and other substances, thereby creating radicals.

*Properties of bubbles vary depending on the generation method, and it is not the case that all fine bubbles produce effects like the above.

Now preparing.