Filter Device Cylindrical Compensating Body

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Solution Overview

Problem

Existing filter devices with cellular rubber compensating bodies are inadequate in managing volume increases during the filtration of aqueous urea solutions, leading to potential damage from freezing fluids due to stiff material behavior that fails to effectively smooth out pressure peaks.

Innovation Solution

A filter device with a cylindrical compensating body featuring channels separated by longitudinal webs and air chambers between inner and outer cylinder surfaces, made from flexible materials like EPDM or HNBR, allowing for enhanced volume compensation and pressure management during freezing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a cellular rubber compensating body is used, then pressure peaks can be smoothed out, but the material is too stiff to effectively compensate for volume increases during freezing

Engineering Contradiction:
Improvepressure peak smoothingVSAvoidflexibility for volume compensation
Core Design Contradiction:
Stress or pressureVSAdaptability or versatility

Solution Approach 1:

The compensating body is divided into multiple air chambers separated by longitudinal webs, creating a segmented structure that enhances flexibility while maintaining pressure smoothing capability. Each chamber can independently deform to accommodate volume changes during freezing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the material parameter from solid cellular rubber to flexible material with internal air chambers, fundamentally altering the compensating body's mechanical properties to achieve both pressure smoothing and high flexibility for freeze protection.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a solid cellular rubber compensating body is used, then structural stability is maintained, but volume compensation during freezing is insufficient

Engineering Contradiction:
Improvestructural stabilityVSAvoidvolume compensation capacity
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The patent introduces air chambers into the compensating body structure, utilizing pneumatic principles to enable significant volume changes. The air-filled chambers can expand and contract to accommodate the 9% volume increase that occurs when aqueous urea solutions freeze, while the flexible material walls maintain structural integrity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Strength

If the compensating body material is made stiff, then pressure resistance is improved, but damage to filter element during freezing increases

Engineering Contradiction:
Improvepressure resistanceVSAvoiddamage to filter element
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent replaces stiff cellular rubber with flexible material walls forming air chambers, allowing the compensating body to deform gently under pressure. This flexibility prevents the transmission of damaging pressure peaks to the filter element during freezing, while the chamber structure maintains adequate pressure resistance.

Inventive Principle:
Principle #30Flexible shells and thin films

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 flexible compensating body effectively reduces pressure peaks and ensures reliable antifreeze protection for the filter element by accommodating volume increases without harming the filter medium, preventing damage from freezing fluids.

Implementation Method 1

the flexible element is designed to absorb the expansion of a liquid as it transitions into a solid

Methodology Applied
Scientific EffectVolume expansion during phase change: Phase Change

Implementation Method 2

the air chambers, which are formed between the inner and outer cylindrical surfaces of the compensating body and extend over a large part of the axial length of the compensating element

Methodology Applied
Scientific EffectCompressibility of air: Compression

Implementation Method 3

the compensating element with internal air chambers, due to its significantly more flexible material properties, provides the volume compensation required when the fluid freezes, with a comparatively small pressure increase that is harmless to the filter medium

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3334513B1Filter device together with a filter element
Publication Date: 2020.01.08 HYDAC FILTERTECHNIK GMBH
  • EP3334513B1 patent drawingFigure 1~3
  • EP3334513B1 patent drawingFigure 4

AI summary

The invention relates to a filter device for filtering fluid, in particular in the form of an aqueous urea solution, comprising a filter housing (1) and at least one filter element (7) arranged therein, as well as comprising a flexible compensation element (35) which is arranged between the outer side of the filter medium (8) of the respective filter element (7) and the adjacent inner wall of the filter housing (1) for compensating for pressure- and/or volume fluctuations of the fluid, and which forms a cover on at least a majority of the axial length of the filter element (7) and encloses the same, characterized in that a compensation element (35) is provided in the form of a cylindrical hollow body, in which a plurality of air chambers (41) is formed between inner cylinder surface (39) and outer cylinder surface (37), which extend across a majority of the axial length of the compensation element (35).