Hydraulic Tank Vent Filtration With Relief Valves and Drainback

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Solution Overview

Problem

Existing liquid tank vents fail to effectively prevent the ingress of water and contaminants into hydraulic tanks while also efficiently managing airflow and moisture removal, leading to potential system malfunctions and oxidation issues.

Innovation Solution

A breather vent system with a vent housing, integrated relief valves, and a filter assembly that includes pleated filter media to filter air and prevent liquid ingress, featuring a draining pathway to return splashed liquid and a design that accommodates airflow based on pressure differentials to manage tank pressure fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a vent allows free airflow to manage tank pressure, then pressure regulation is improved, but water and contaminants can ingress into the tank

Engineering Contradiction:
Improvetank pressure regulationVSAvoidwater and contaminant ingress
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The vent incorporates a filter assembly with pleated filter media that acts as a porous barrier, allowing air molecules to pass through while blocking larger contaminants and water droplets. The pleated structure provides high surface area filtration capability while maintaining airflow pathways for pressure equalization.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The relief valves serve as intermediary components that mediate between the internal tank pressure and external atmospheric pressure. They selectively open to allow airflow in either direction when pressure differentials exceed threshold values, enabling pressure management without continuous exposure to contaminants.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a filter assembly is added to prevent contaminant ingress, then protection against oxidation is improved, but airflow management becomes restricted

Engineering Contradiction:
Improvecontaminant protectionVSAvoidairflow efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The filter media is designed as a porous material with controlled pore sizes that permit gas molecules to pass while blocking liquid and particulate contaminants. The pleated configuration maximizes the filtering surface area within a compact volume, maintaining airflow efficiency.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The system dynamically switches between filtered airflow mode (during normal operation) and direct relief valve mode (during extreme pressure differentials). The relief valves provide a bypass pathway that opens only when necessary, maintaining filtration efficiency while allowing unrestricted pressure equalization when needed.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If relief valves are integrated into the vent housing, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecomponent integrationVSAvoidvalve seating accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The inlet relief valve and outlet relief valve are integrated into a single housing structure with the filter assembly, creating a compact multi-functional component. This merging reduces the number of separate parts and assembly steps while maintaining functional independence of each valve mechanism.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The relief valves utilize elastomeric materials that provide inherent compliance and sealing capability. The elastomeric properties allow for tolerance compensation and reduce the need for extremely tight manufacturing tolerances while maintaining reliable valve seating and controllable opening pressures.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively prevents water and contaminant ingress, manages airflow and moisture, and returns splashed liquid to the tank, enhancing system reliability and preventing oxidation, thus improving the operational stability of hydraulic systems.

Implementation Method 1

The inlet relief valve is biased in a closed position and is configured to open upon a pressure differential of the second airflow pathway relative to the first airflow pathway exceeding a first threshold pressure

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

A filter assembly is disposed in the vent housing. The filter assembly extends across the second airflow pathway

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 3

a draining pathway extending from the first airflow pathway through the first end of the vent housing

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4288298B1Vent for hydraulic tank
Publication Date: 2024.11.13 DONALDSON CO INC
  • EP4288298B1 patent drawingFigure 1~2
  • EP4288298B1 patent drawingFigure 3
  • EP4288298B1 patent drawingFigure 4

AI summary

A vent having a vent housing defining a mounting structure, a first opening between a first end and a second end of the vent housing, a first airflow pathway from the first opening, a second airflow pathway from a second opening, and a draining pathway from the first airflow pathway through the first end of the vent housing. The first airflow pathway has a first segment and a second segment extending in opposite axial directions. An inlet relief valve and an outlet relief valve are arranged in parallel between the first and second airflow pathways. The inlet relief valve opens upon exceeding a first threshold pressure differential of the second relative to the first airflow pathway. The outlet relief valve opens upon exceeding a second pressure differential of the first relative to the second airflow pathway. A filter assembly is disposed in the vent housing across the second airflow pathway.