Dual-Filter Hydraulic Cartridge with Bypass Valve

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing hydraulic system filters often become clogged with debris and particulate matter over time, requiring frequent cleaning or replacement, which can disrupt system performance and increase maintenance costs.

Innovation Solution

A filter arrangement featuring a dual-filter cartridge system with a first and second filter element, where the first filter element functions as a suction filter and the second as a return filter, both with bypass valve arrangements to allow fluid to bypass clogged sections, reducing pressure drops and maintaining system efficiency during occlusions or cold-start conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single filter element is used in the hydraulic system, then the filter structure is simple and cost-effective, but the filter becomes clogged with debris and particulate matter over time, requiring frequent cleaning or replacement

Engineering Contradiction:
Improvefilter service lifeVSAvoidfilter structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The filter element is divided into multiple filtering zones with different pore sizes arranged in series. The first filtering zone has a first pore size, the second filtering zone has a second pore size smaller than the first, and the third filtering zone has a third pore size smaller than the second. This segmentation allows progressive filtration where larger particles are captured first and smaller particles are captured in subsequent zones, extending the overall service life of the filter element.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the filter element have different filtering characteristics tailored to specific needs. The upstream portions have larger pore sizes to handle higher flow rates and capture larger contaminants, while downstream portions have smaller pore sizes for finer filtration. This local differentiation optimizes both filtration efficiency and flow characteristics at different stages of the filtering process.

Inventive Principle:
Principle #3Local quality

2Duration of action of moving object

If a dual-filter element system is implemented to extend filter life, then maintenance frequency is reduced, but the filter cartridge complexity and manufacturing cost increase

Engineering Contradiction:
Improvefilter operational durationVSAvoidfilter cartridge assembly
Core Design Contradiction:
Duration of action of moving objectVSEase of manufacture

Solution Approach 1:

The filter element is constructed with nested cylindrical structures where the first, second, and third filtering zones are arranged concentrically. The inner filtering zone is positioned within the outer filtering zones, creating a compact nested configuration. This nesting approach maximizes the filtering surface area within a constrained volume and simplifies the overall cartridge assembly compared to using multiple separate filter elements.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Multiple filtering zones with different pore sizes are combined into a single integrated filter element rather than using separate filter cartridges. The filtering zones are positioned in series within the same fluid flow path, allowing the system to benefit from extended service life while maintaining a single-cartridge replacement approach, thereby simplifying maintenance procedures.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If multiple filtering zones with different pore sizes are used in series, then filtration efficiency is improved, but the pressure drop across the filter increases

Engineering Contradiction:
Improvefiltration precisionVSAvoidpressure drop
Core Design Contradiction:
Manufacturing precisionVSStress or pressure

Solution Approach 1:

The filter element incorporates a bypass valve that dynamically adjusts the flow path based on pressure differential. When the pressure drop across the filtering zones becomes excessive, the bypass valve opens to allow a portion of the fluid to bypass the filter media, thereby maintaining acceptable flow rates while still providing filtration through the parallel path. This dynamic adjustment prevents system shutdown due to high pressure drops.

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If the filter is designed for frequent replacement rather than cleaning, then maintenance simplicity is improved, but operational downtime and long-term costs increase

Engineering Contradiction:
Improvemaintenance simplicityVSAvoiddowntime
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The multi-zone filter element with bypass capability ensures continuous filtration service by maintaining adequate flow rates even as the filter media becomes loaded with contaminants. The bypass valve activates when pressure differential increases, allowing the system to continue operating with reduced filtration efficiency rather than shutting down completely. This extends the operational life of the filter element between replacements and reduces downtime.

Inventive Principle:
Principle #20Continuity of useful action

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 dual-filter system effectively extends filter life by allowing fluid to bypass clogged sections, reducing maintenance frequency and maintaining hydraulic system performance, especially during cold-start conditions, thereby minimizing downtime and operational costs.

Implementation Method 1

A filter arrangement includes a filter cartridge having a first filter element and a second filter element. The first filter element includes a first tubular section of filter media extending between first and second end caps and defining a first open filter interior.

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

both with bypass valve arrangements to allow fluid to bypass clogged sections, reducing pressure drops and maintaining system efficiency during occlusions or cold-start conditions

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP2508239B1Filter arrangement and methods
Publication Date: 2016.09.14 DONALDSON CO INC
  • EP2508239B1 patent drawingFigure 1
  • EP2508239B1 patent drawingFigure 2
  • EP2508239B1 patent drawingFigure 3

AI summary

A filter arrangement includes a filter cartridge having a first filter element and a second filter element. The first filter element includes a first tubular section of filter media extending between first and second end caps and defining a first open filter interior. The second filter element includes a second tubular section of filter media operably oriented in the first open filter interior. The second tubular section of filter media extends between third and fourth end caps and defines a second open filter interior. The first end cap defines an inner container and an outer container circumscribing the inner container. The outer container is secured to the first tubular section of filter media. The inner container has an end wall axially spaced from the outer container. The third end cap has a media end secured to the second tubular section of filter media and a tubular wall axially extending from the media end. The tubular wall is circumscribed by the inner container of the first end cap. The filter arrangement further includes a housing for the cartridge, and can be either a spin-on or a bowl-cartridge filter. The filter arrangement is usable in a hydraulic system including a sump; an implement valve; a pump; and a filter head in fluid communication with the sump, implement valve, pump, and filter arrangement.