Automatically Cleanable Milk Filter With Turbulent Countercurrent Flow

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Solution Overview

Problem

Existing milk filters for milking devices are not adequately cleanable, leading to frequent replacement and high material consumption, and existing countercurrent cleaning methods do not effectively clean the upper filter openings due to laminar boundary layers that prevent thorough cleaning.

Innovation Solution

A milk filter with a cylindrical housing and a concentric cylindrical filter part featuring a unilaterally tapering cross-sectional profile and spiral-shaped wire or rings, allowing for countercurrent cleaning that accelerates the transition from laminar to turbulent boundary layers, enhancing cleaning efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional milk filter with filter openings is used, then milk filtration is achieved, but the filter openings become difficult to clean and require frequent replacement

Engineering Contradiction:
Improvefilter cleanabilityVSAvoidfilter replacement frequency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies inversion by reversing the cleaning flow direction relative to milk flow. Cleaning liquid is introduced at the second liquid connection (top) and flows downward through the filter openings in the opposite direction to milk flow, enabling effective removal of contaminants from the filter surface that cannot be achieved with conventional cleaning methods.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the flow regime parameter from laminar to turbulent by introducing cleaning liquid at high velocity through the second liquid connection. This turbulent flow regime enhances the cleaning effect by creating strong shear forces that effectively remove contaminants from the filter openings, solving the cleanability problem.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If countercurrent cleaning is applied to the filter, then cleaning efficiency improves, but laminar boundary layers prevent thorough cleaning of upper filter openings

Engineering Contradiction:
Improvecleaning efficiencyVSAvoidcleaning completeness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the flow regime parameter from laminar to turbulent by introducing cleaning liquid at high velocity through the second liquid connection. This turbulent flow regime enhances the cleaning effect by creating strong shear forces that effectively remove contaminants from the filter openings, solving the cleanability problem.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent adds a dimensional element by extending the cylindrical part beyond the filter openings in the cleaning liquid flow direction. This extension creates an additional flow path dimension that ensures turbulent cleaning action reaches all filter openings, including those at the upper extent, eliminating blind spots in the cleaning process.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If filter sleeves are replaced frequently, then clean milk filtration is maintained, but labor and material consumption increase

Engineering Contradiction:
Improvemilk filtration qualityVSAvoidoperational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements self-service by enabling the filter to clean itself through the automated countercurrent cleaning system. The cleaning liquid flows through the filter in the opposite direction to milk, automatically removing contaminants without manual intervention, thereby eliminating the need for frequent filter replacements and improving operational efficiency.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Instead of discarding the filter after single-use, the patent recovers the filter's functionality through automated cleaning. The countercurrent cleaning system restores the filter openings by removing accumulated contaminants, allowing the same filter to be reused multiple times while maintaining filtration quality.

Inventive Principle:
Principle #34Discarding and recovering

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 filter design improves cleanability by ensuring thorough cleaning of all filter openings, reducing the need for frequent replacements and material consumption, while maintaining efficient milk flow.

Implementation Method 1

accelerates the transition from laminar to turbulent boundary layers, enhancing cleaning efficiency

Methodology Applied
Scientific EffectBoundary layer transition from laminar to turbulent flow: Boundary Layer

Implementation Method 2

allowing for countercurrent cleaning that accelerates the transition from laminar to turbulent boundary layers

Methodology Applied
Scientific EffectCountercurrent flow cleaning: Convection

Implementation Method 3

a substantially concentric cylindrical filter part containing a plurality of filter openings with a smallest dimension of between 60 and 100 μm

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP4376597B1Milking device provided with a milk filter
Publication Date: 2025.07.02 LELY PATENT NV
  • EP4376597B1 patent drawingFigure 1~2
  • EP4376597B1 patent drawingFigure 3
  • EP4376597B1 patent drawingFigure 4~5

AI summary

An automatically cleanable milk filter (8) comprises a cylindrical housing (23) with a outer wall, a first end (15) with a first liquid connection, and above a second end (17) with a second liquid connection. A concentric cylindrical filter part (21) and a cylindrical core (20) which is placed concentrically within the filter part are accommodated in the housing. The filter part includes wire having a tapered cross-sectional profile in a spiral shape or as a series of parallel rings or rods, and a frame for keeping them spaced apart, thereby forming a plurality of filter openings (31). The filter part divides the filter volume into a first volume part (24) which is directly connected to the first liquid connection, and a second volume part (22) which is directly connected to the second liquid connection. The second volume part (22) comprises a cylindrical part, as well as a top part which narrows at a transition to the second liquid connection. The cylindrical part, viewed in a direction towards the second liquid connection, extends beyond the plurality of filter openings in the filter part, and the first volume part, viewed in a direction towards the second liquid connection, does not extend beyond the filter part. In this way, the stream of cleaning liquid, supplied from above, can develop beyond the top part to form a more turbulent stream parallel to the cylindrical part. In addition, a milking device comprising this milk filter is provided.