Microbubble Generator Slit Structure for Stronger Cavitation

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Solution Overview

Problem

Existing bubble generators face challenges in achieving high microbubble generating efficiency, as they often rely on cavitation effects that are not sufficient to produce a substantial number of microbubbles in water flows.

Innovation Solution

A bubble generator design featuring a tubular main body with radially extending slits and protruding columns, where the columns gradually reduce in protrusion towards the upstream side and have recesses on their downstream surfaces, creating multiple vacuum areas that enhance microbubble generation by increasing water flow velocity and promoting gas release from dissolved gases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If columns protrude from the inner peripheral surface to form slits, then microbubble generation is improved, but the structure becomes more complex

Engineering Contradiction:
Improvemicrobubble generation efficiencyVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The inner peripheral surface is segmented into multiple columns that protrude to form slits between them. This segmentation creates multiple flow restriction points that generate vacuum areas, thereby improving microbubble generation efficiency while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The columns have varying protrusion amounts, with the protrusion gradually reducing from the periphery toward the upstream side. This local variation in geometry creates different flow characteristics at different locations, optimizing vacuum area formation and microbubble generation without requiring complex external control mechanisms.

Inventive Principle:
Principle #3Local quality

2Productivity

If the protrusion amount of columns is varied to create vacuum areas, then microbubble generation is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvemicrobubble generation efficiencyVSAvoidprotrusion amount precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The protrusion amount of the columns is designed to change gradually along the upstream direction, creating a parameter gradient. This gradual change produces the necessary vacuum areas for microbubble generation while allowing for more tolerant manufacturing specifications compared to abrupt geometric changes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The columns are pre-formed with specific protrusion amounts during the molding process. By preliminarily establishing the correct geometry in the mold, the actual manufacturing process requires less precision adjustment, as the vacuum-generating structure is built-in from the start.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If recesses are added to the downstream-side surfaces of columns, then microbubble generation is improved, but device complexity increases

Engineering Contradiction:
Improvemicrobubble generation efficiencyVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The recesses are integrated directly into the downstream-side surfaces of the columns, merging the vacuum generation function with the existing column structure. This combination creates additional vacuum areas without requiring separate components, thereby improving microbubble generation while minimizing the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The recesses are nested within the column structures themselves, with each column containing a recess on its downstream surface. This nesting approach allows multiple vacuum-generating features to be packed into the existing structure, enhancing performance without proportionally increasing overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design significantly increases microbubble generation efficiency by creating multiple vacuum areas, allowing for the production of a sufficient amount of nanobubbles without the need for additional pressure sources, such as pumps, and can be applied to various water flow sources.

Implementation Method 1

a flow path in the main body is restricted so that the velocity of a water flow in the main body increases due to compression. When such a water flow passes through the slits, vacuum areas are created downstream from the slits.

Methodology Applied
Scientific EffectBernoulli's principle: Bernoulli Effect

Implementation Method 2

gases dissolved in the water are released due to a cavitation effect (effect of reduced pressure) so that microbubbles are generated

Methodology Applied
Scientific EffectCavitation effect: Cavitation

Data Source

PatentEP3488920B1Bubble generating device
Publication Date: 2021.07.21 SHIBATA OU
  • EP3488920B1 patent drawingFigure 1~2
  • EP3488920B1 patent drawingFigure 3
  • EP3488920B1 patent drawingFigure 4

AI summary

The purpose of the present invention is, in a bubble generating device provided with a bubble generating unit for generating minute bubbles in water flowing through the inside of the cylindrical main body unit, to improve the bubble generating efficiency of the bubble generating unit. Provided is a bubble generating device provided with a cylindrical main body unit and a bubble generating unit disposed within the main body, wherein: the bubble generating unit is provided with slits extending radially centered on one point within the main body unit in a cross-sectional plane of the main body unit, and a column part protruding from the inner peripheral surface of main body unit and formed on the peripheral edge of the slits; and the amount of protrusion of the column part is gradually reduced toward the upstream side from the peripheral edges of the slits, and the column part has a recessed part formed on the downstream surface.