Bypass Valve Filter Element for Hydraulic Oil

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Solution Overview

Problem

Existing filter assemblies for liquid filtration, such as hydraulic oil, are complex and lack efficient mechanisms to manage increased pressure and media pack restrictions, leading to potential bypass issues and reduced filtration effectiveness.

Innovation Solution

A liquid filter assembly with a housing, support member, and filter element that includes a media pack and a bypass valve arrangement. The bypass valve allows unfiltered liquid to bypass the media pack when pressure exceeds a threshold, using a dynamic seal and biasing member to control flow, ensuring efficient filtration and preventing media pack overload.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bypass valve arrangement is added to allow unfiltered liquid to bypass the media pack under high pressure, then filtration efficiency is maintained and media pack overload is prevented, but device complexity increases

Engineering Contradiction:
Improvefiltration efficiencyVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bypass valve arrangement is integrated into the filter element structure itself, combining the filtration function with the pressure relief function in a single compact assembly. The valve head, valve seat, and biasing member are incorporated within the filter element housing, eliminating the need for separate bypass mechanisms and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bypass valve operates automatically based on pressure differential across the media pack. When pressure exceeds the threshold, the valve head is pushed off the valve seat by the biasing member, allowing unfiltered liquid to bypass the media pack without requiring external control systems or manual intervention. This self-regulating mechanism maintains filtration efficiency while preventing media pack overload.

Inventive Principle:
Principle #25Self-service

2Reliability

If a dynamic seal is used to control bypass flow, then operational reliability is enhanced, but manufacturing precision requirements increase

Engineering Contradiction:
Improveoperational reliabilityVSAvoidseal engagement precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The dynamic seal utilizes the pressure differential parameter across the media pack to control valve operation. When pressure differential increases beyond a threshold, the seal dynamically transitions from a closed state (valve head sealed against valve seat) to an open state (bypass flow enabled). This parameter-based control mechanism enhances operational reliability while accommodating reasonable manufacturing tolerances through pressure-actuated operation.

Inventive Principle:
Principle #35Parameter changes

3Ease of repair

If the filter element is designed to be removably and replaceably oriented, then ease of maintenance is improved, but device complexity increases

Engineering Contradiction:
Improvemaintenance easeVSAvoidfilter element structure
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The filter element is designed as a separate, removable module that can be independently replaced without disassembling the entire filter assembly. The support member, media pack, end caps, and bypass valve arrangement are integrated into a single replaceable filter element unit. This segmentation allows for easy maintenance by simply removing and replacing the filter element, while the internal integration of components minimizes the complexity increase.

Inventive Principle:
Principle #1Segmentation

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 provides improved filtration efficiency by allowing unfiltered liquid to bypass the media pack under high pressure conditions, maintaining filtration quality and extending the life of the media pack, thus simplifying the assembly and enhancing operational reliability.

Implementation Method 1

a biasing member operably held by the bias member seat... the valve head being within the bias member seat and engaged against the biasing member

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A dynamic seal is provided. The dynamic seal is engaged as the valve head moves into and out of sealing engagement.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2981344B1Liquid filter assembly and methods
Publication Date: 2020.11.18 DONALDSON CO INC
  • EP2981344B1 patent drawingFigure 1
  • EP2981344B1 patent drawingFigure 2
  • EP2981344B1 patent drawingFigure 3

AI summary

A liquid filter assembly includes a porous tubular support member and a filter element removably and replaceably oriented in the interior volume of the support member. A bypass valve arrangement is provided to permit at least some unfiltered liquid to bypass media in the filter element. A dynamic seal can help to seal the b ass valve arrangement.