Bellows Compensator B:T Ratio for Hygienic Heat Exchangers

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Solution Overview

Problem

Tubular heat exchangers face challenges in achieving hygienic cleaning due to dead spaces and high local stresses in bellows, which hinder effective product flow and thermal expansion compensation, especially in the food industry where product contact occurs.

Innovation Solution

Designing bellows with a B:T ratio of about 1 or greater on the product-contactable surface, featuring moderate changes in direction and weakly curved surfaces, and using a hybrid design with both concave and convex sections to enhance cleaning efficiency and compensation effect, while minimizing dead spaces and local stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bellows with small B:T ratio are used to achieve strong compensation effect, then thermal expansion compensation is improved, but hygienic cleaning becomes impossible due to product deposits

Engineering Contradiction:
Improvethermal expansion compensationVSAvoidhygienic cleaning
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies different B:T ratios to different sections of the bellows: the product-contactable surface has folds with B:T ratio of about 1 or greater for easy cleaning, while the non-contactable sections can have different characteristics. This local differentiation allows the bellows to maintain both hygienic properties and compensation functionality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bellows is segmented into different functional zones: a product-contactable surface with specific fold characteristics for hygiene, and an inner surface with different characteristics for compensation. This segmentation allows each zone to be optimized for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If bellows with large B:T ratio are used to facilitate cleaning, then hygienic conditions are improved, but compensation effect is reduced

Engineering Contradiction:
Improvehygienic cleaningVSAvoidthermal expansion compensation
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies different B:T ratios to different sections of the bellows: the product-contactable surface has folds with B:T ratio of about 1 or greater for easy cleaning, while the non-contactable sections can have different characteristics. This local differentiation allows the bellows to maintain both hygienic properties and compensation functionality.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If narrow V-shaped folds are provided to reduce dead spaces, then cleaning is improved, but compensation effect is reduced due to high local stresses

Engineering Contradiction:
Improvecleaning efficiencyVSAvoidcompensation effect
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies different B:T ratios to different sections of the bellows: the product-contactable surface has folds with B:T ratio of about 1 or greater for easy cleaning, while the non-contactable sections can have different characteristics. This local differentiation allows the bellows to maintain both hygienic properties and compensation functionality.

Inventive Principle:
Principle #3Local quality

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

This approach allows for hygienic cleaning of product-contactable surfaces, reduces residue sticking, and ensures efficient removal of residues, while maintaining sufficient thermal expansion compensation, thus achieving hygienically perfect conditions and favorable flow conditions in tubular heat exchangers.

Implementation Method 1

The inner and outer tubes have congruent bellows... which compensate for the different thermal expansions of the inner and outer tubes

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the bellows are designed with a B:T ratio of about 1 or greater... the compensation effect occurs predominantly in the turning points

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2299226B1Tubular heat exchanger with bellows compensator
Publication Date: 2019.11.13 KRONES AG
  • EP2299226B1 patent drawingFigure 1~3
  • EP2299226B1 patent drawingFigure 4~5

AI summary

The heat exchanger (W) has an inner tube (3) for treating fluid food products. A thermal expansion compensation device (K) is provided for a casing tube (1) and/or the inner tube, and has a surface (12) contactable by the product to be treated. The surface is provided at a bellows (C) that is integrated into the casing- and/or inner tubes and has folds (F) rotating around a tube axis. Each of the folds at the surface is formed with a radial depth and an axial breadth with ratio of 1 or grater than 1.