A new dimension in water recycling

Extracting impurities through the power of bubbles

Microbubble cleaning technology

Microbubble cleaning technology enables recycling of cleaning water

Problems with oil grime

  • Large volumes of water and detergent are necessary to remove oil from parts in factories as the oil is dissolved in detergent.
  • It is difficult to reuse water used for cleaning, as it contains oil and detergents washed off in the cleaning process.

Microbubbles are microscopic bubbles 1/100th the size of normal bubbles (0.1 millimeter in diameter, less than 100 microns). They have the ability to adsorb microscopic impurities and have particularly high adsorption ability in regards to oil. This is because oil is naturally repelled by water, and is therefore attracted to any other substance present in water. Moreover, in contrast to the usual type of bubbles, which rise to the water surface immediately, microbubbles rise slowly.

Microbubble technology makes it possible to remove oil without using detergent. Oil is inherently hydrophobic and attracted to air. Therefore, it gathers on the water surface together with the microbubbles and is removed, making it possible to reuse the cleaning water.

  • photo: Microbubbles (0.1 millimeter in diameter, less than 100 microns)

    (0.1 millimeter in diameter, less than 100 microns)

  • photo: Usual type of bubble (about 10 millimeters in diameter)

    Usual type of bubble (about 10 millimeters in diameter)

  • diagram: Adsorption Properties of Microbubbles

Industrial use

To expand the utilization of microbubble cleaning in industry, in addition to the orthodox method of generating microbubbles in a water tank, we have developed various cleaning methods including spraying microbubbles (see diagram below).

Mitsubishi Electric also utilizes microbubbles for cleaning parts in its plating facilities and for sorting processes that utilize water in its plastics recycling facilities.

photo: Microbubble cleaning equipment

Microbubble cleaning equipment


Applications for products

The Eco Cute natural refrigerant (CO2) heat-pump water heater is an example of a Mitsubishi Electric product that uses microbubble technology.

Normally, hot-water heaters and bathtubs are connected by a long pipe. When reheating bathwater, the water is circulated inside the pipe and repeatedly reused, and sebaceous material can accumulate. To remove this, the Eco Cute is equipped with a microbubble self-cleaning mechanism.

The mechanism starts automatically when the bathtub plug is pulled and is a popular feature as it saves users the hassle of cleaning the pipe themselves.

diagram: Mitsubishi Eco Cute