Hydraulic Fluid Filter Cartridge With Anti-Emptying Air Bubble Control

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Solution Overview

Problem

Existing hydraulic filters fail to effectively eliminate air bubbles and contaminants from hydraulic fluids, particularly during transient conditions, leading to cavitation, noise, and reduced thermal conductivity, while being cumbersome and difficult to maintain.

Innovation Solution

A filter design with a tubular filtering cartridge and anti-emptying device that includes hydraulic fluid interception means and a by-pass mechanism, allowing for efficient filtration and air bubble reduction, while ensuring easy maintenance and installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional hydraulic fluids with additives are used to improve system performance, then lubrication and corrosion protection are enhanced, but sludge and varnish deposits form on circuit components

Engineering Contradiction:
Improvelubrication and corrosion protectionVSAvoidsludge and varnish deposits
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the problematic additives (anti-wear agents, extreme pressure agents, corrosion inhibitors) from the hydraulic fluid formulation. By eliminating these additives that cause sludge and varnish deposits, the fluid maintains basic lubrication properties without generating harmful deposits on circuit components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical composition parameters of the hydraulic fluid by specifying exact ranges for base oil viscosity (10-500 cSt at 40°C) and eliminating additive packages. This parameter change transforms the fluid from an additive-heavy formulation to an additive-free formulation that prevents deposit formation while maintaining necessary lubrication through optimized base oil selection.

Inventive Principle:
Principle #35Parameter changes

2Strength

If hydraulic fluids are formulated with multiple additives to enhance protection, then component durability improves, but filter clogging and component plugging occur

Engineering Contradiction:
Improvecomponent durabilityVSAvoidfilter maintenance requirements
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent removes additive packages from the hydraulic fluid formulation that are responsible for forming deposits which clog filters and plug components. By extracting these problematic substances, the fluid maintains component protection through optimized base oil properties alone, eliminating filter maintenance issues.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent enables the hydraulic fluid to provide its own protection through carefully selected base oils with inherent lubricating properties, eliminating the need for additives that cause deposit formation. The fluid serves itself by using base oil viscosity and composition to provide lubrication and protection without external additive assistance.

Inventive Principle:
Principle #25Self-service

3Productivity

If standard hydraulic fluids are used to maintain system operation, then circuit functionality is preserved, but microbial growth and contamination occur

Engineering Contradiction:
Improvecircuit functionalityVSAvoidmicrobial growth and contamination
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent creates an inert environment for microbial growth by formulating the hydraulic fluid without organic additives that serve as food sources for bacteria and fungi. The additive-free formulation, particularly when using synthetic base oils, creates an environment hostile to microbial growth, preventing contamination while maintaining circuit functionality.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent changes the chemical composition parameters by eliminating organic additives and specifying base oils with properties that resist microbial growth. This parameter change transforms the fluid from a microbe-friendly formulation to one that inherently resists contamination while preserving hydraulic circuit operation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4580778B1Filter for hydraulic fluids for hydraulic circuits
Publication Date: 2026.05.06 MP FILTRI
  • EP4580778B1 patent drawingFigure 1
  • EP4580778B1 patent drawingFigure 2
  • EP4580778B1 patent drawingFigure 3

AI summary

A filter (1) for hydraulic fluids for hydraulic circuits comprising a filter body (2) inside which a filtering cartridge (6) is housed, said filter body (2) comprises at least one hydraulic fluid inlet (4) in communication with a supply chamber (10) located upstream of said filtering cartridge (6), comprising a first tubular element (14) which is circumscribed about said filtering cartridge (6) and comprises a respective plurality of passages (15) in order to be crossed by a flow of hydraulic fluid, as well as a second tubular element (16) circumscribed about and spaced apart from said first tubular element (14) and comprising a respective plurality of passages (18) in order to be crossed by a flow of hydraulic fluid passing through said continuous tubular layer of filtering material (8) and through said first tubular support element (14).