Float Air Vent Structure for Filter Leak and Backflow Prevention

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Solution Overview

Problem

Existing filter devices allow air to flow back into the filter when the engine is stopped, and there is a risk of liquid outflow or air backflow through the air vent hole, which is not effectively addressed by existing technologies.

Innovation Solution

A filter device with a columnar air vent hole featuring a first tapered hole portion and a second tapered hole portion, where a float with a smaller specific gravity than the liquid occludes these holes to prevent air backflow and liquid outflow, and is designed to discharge trapped air by moving between positions to allow air passage when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a simple air vent hole is provided, then air can be discharged from the filter device, but liquid may leak out or air may flow backward through the air vent hole

Engineering Contradiction:
Improveprevention of liquid leakage and air backflowVSAvoidstructure of air vent hole
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The air vent hole is segmented into three distinct portions: a columnar hole main body portion, a first tapered hole portion on the upper side, and a second tapered hole portion on the lower side. Each portion serves a specific function in controlling fluid flow, with the tapered portions creating narrowing passages that prevent liquid leakage and air backflow while allowing air discharge when the float moves to appropriate positions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A float is introduced as an intermediary element that moves between positions to occlude or open different portions of the air vent hole. The float responds to liquid level changes and air pressure, automatically controlling the opening and closing of the air vent hole without requiring external control mechanisms, thus preventing liquid leakage and air backflow while enabling air discharge when needed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the air vent hole remains open to discharge air, then trapped air can be released, but air may flow backward into the filter when the engine is stopped

Engineering Contradiction:
Improveprevention of air backflowVSAvoidair discharge capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The air vent hole system is made dynamic through the float mechanism. The float moves automatically in response to changing conditions (liquid level, air pressure), dynamically opening or closing the air vent hole. This dynamic control allows air to be discharged when trapped (when the float moves to allow opening) while preventing air backflow when the engine is stopped (when the float moves to occlude the hole), thus resolving the contradiction between air discharge capability and air backflow prevention.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a float is added to control the air vent hole, then liquid leakage and air backflow can be prevented, but the device complexity increases

Engineering Contradiction:
Improveprevention of liquid outflow and air backflowVSAvoidair vent portion structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The float is designed to be self-actuating, responding automatically to liquid level changes and air pressure variations without requiring external control systems. The float's buoyancy and the pressure differential cause it to move to appropriate positions, automatically occluding or opening the air vent hole portions as needed. This self-service mechanism prevents liquid outflow and air backflow while minimizing the need for additional complex control components.

Inventive Principle:
Principle #25Self-service

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

Effectively discharges trapped air and prevents liquid outflow or air backflow through the air vent hole, ensuring the filter device operates efficiently and reliably.

Implementation Method 1

the float is formed of the material having a smaller specific gravity than the liquid to be filtered. The float is thus pushed up by the liquid to occlude the first hole portion to allow the liquid to be prevented from leaking through the air vent hole

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

the float is pushed up by air to allow the air trapped inside the filter device to be discharged through the air vent hole

Methodology Applied
Scientific EffectAir pressure: Pressure Increase

Implementation Method 3

The float occludes the second hole portion under the weight of the float. However, the float is pushed up by air to allow the air trapped inside the filter device to be discharged through the air vent hole. The float also occludes the second hole portion to allow air to be prevented from flowing backward through the air vent hole

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3480476B1Filter device
Publication Date: 2021.11.03 YAMASHIN FILTER CORP
  • EP3480476B1 patent drawingFigure 1
  • EP3480476B1 patent drawingFigure 2
  • EP3480476B1 patent drawingFigure 3

AI summary

Air collected in a filter device can be discharged, and outflow of a liquid from the filter device or backward flow of air through an air vent hole can be prevented. The air vent hole includes a substantially columnar hole main body portion, a first hole portion formed on the upper side of the hole main body portion, and a second hole portion formed on the lower side of the hole main body portion. Each of the first hole portion and the second hole portion partly has, in a cross section of the hole portion substantially orthogonal to a first direction that is a longitudinal direction of the hole main body portion, a cross-sectional area smaller than a cross-sectional area of a cross section of the hole main body portion substantially orthogonal to the first direction. A float inserted into the air vent hole is movable between a position where the float occludes the first hole portion and a position where the float occludes the second hole portion. The float occludes the first hole portion under the weight of the float. However, the float is pushed up by air. Furthermore, the float is formed of a material having a smaller specific gravity than a liquid to be filtered. Thus, the float is pushed up by the liquid to occlude the first hole portion.