Single Screw Flow Meter for High-Viscosity Liquids

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Solution Overview

Problem

Existing flow meters are either too heavy and complex for mobile applications when measuring high-viscosity liquids, or they lack accuracy for such applications due to their design limitations, particularly for liquids like plastics, bitumen, or adhesives, where turbine flow meters fail to provide reliable measurements.

Innovation Solution

A lightweight flow meter design featuring a single screw spindle with a high outer-to-core diameter ratio of at least 1.5:1, three wings defining three screw threads, and a helix angle of 15°, which minimizes pressure loss and ensures sufficient rotation for high-viscosity liquids, integrated with a slide bearing and influence equalizer for optimal flow behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a turbine flow meter is used, then the weight is low and the structure is simple, but the measurement accuracy deteriorates for high-viscosity liquids

Engineering Contradiction:
ImproveweightVSAvoidmeasurement accuracy
Core Design Contradiction:
Weight of moving objectVSMeasurement precision

Solution Approach 1:

The patent replaces the turbine flow meter's direct mechanical rotation system with a magnetic coupling system. The screw spindle rotates magnetically coupled to a pole wheel, eliminating direct mechanical connections while maintaining rotational motion for measurement. This substitution preserves the lightweight advantage while enabling accurate measurement of high-viscosity liquids through non-contact magnetic drive.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a spindle flow meter with multiple spindles is used, then the measurement accuracy for high-viscosity liquids is improved, but the weight increases and the structure becomes complex

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the measurement function into two independent parts: a single screw spindle for generating rotational motion and a pole wheel for measurement detection. This segmentation allows the screw spindle to be optimized for handling high-viscosity liquids while the pole wheel handles the measurement function, reducing overall structural complexity compared to multiple intermeshing spindles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the screw spindle and the measurement system. The magnetic coupling transmits rotational motion without mechanical connection, eliminating the need for complex mechanical linkages between multiple spindles while maintaining accurate measurement capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If a spindle flow meter with multiple spindles is used, then the measurement accuracy for high-viscosity liquids is improved, but the weight increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidweight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent extracts the measurement function from the multiple-spindle mechanical system and places it in a separate pole wheel that is magnetically driven. This extraction eliminates the weight of additional spindles and their supporting structures while preserving the measurement capability through the magnetic coupling system.

Inventive Principle:
Principle #2Taking out (Extraction)

4Speed

If the outer diameter to core diameter ratio of the screw spindle is increased, then the rotation capability for high-viscosity liquids is improved, but the structural strength may be reduced

Engineering Contradiction:
Improverotation capabilityVSAvoidstructural strength
Core Design Contradiction:
SpeedVSStrength

Solution Approach 1:

The patent optimizes the outer diameter to core diameter ratio of the screw spindle to at least 1.5:1, which enhances the vanes' ability to rotate the spindle through viscous liquids. This parameter change improves rotation capability while the overall structural design compensates for any strength reduction through appropriate material selection and structural reinforcement.

Inventive Principle:
Principle #35Parameter changes

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

Enables accurate and reliable flow measurement of high-viscosity liquids with a large flow ratio of 1:50 to 1:100, suitable for mobile use, such as in spray guns, with minimal weight and turbulence, maintaining high accuracy and reducing production complexity.

Implementation Method 1

for determining the flow of liquids with a viscosity of more than 30 mm2/s

Methodology Applied
Scientific EffectViscous flow:

Implementation Method 2

The pole wheel (40) is designed to be magnetically coupled to the screw spindle (20)

Methodology Applied
Scientific EffectMagnetic coupling:

Implementation Method 3

A slide bearing with a ball attachment can be provided for mounting the screw spindle

Methodology Applied
Scientific EffectFriction reduction: Lubrication

Data Source

PatentEP3382350B1Flow meter
Publication Date: 2020.10.14 CIPON GMBH
  • EP3382350B1 patent drawingFigure 1

AI summary

The invention relates to a flow meter for determining the flow rate of liquids with a viscosity greater than 30 mm²/s. For this purpose, a housing with a cylindrical recess is provided in which a screw spindle is received. The screw spindle has at least one wing, which defines a helical thread, wherein the recess has a length sufficient to enclose half a turn of the helical thread. Furthermore, the ratio of the outer diameter to the core diameter of the screw spindle is at least 1.5:1.