Flowmeter Design for Liquid Measurement Accuracy

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Solution Overview

Problem

Existing flow meters for small liquid amounts face challenges in achieving high measuring accuracy due to air pockets from flow interruptions and are often bulky, costly, and difficult to produce with precise dimensions, especially when using plastic injection molding, which results in burr formation and turbulence at the transition edges.

Innovation Solution

A compact flow meter design featuring a two-part cylindrical measuring housing with a tangentially directed inflow nozzle and a conical bearing pin, incorporating a separate nozzle tube with precise axial positioning to minimize turbulence and air bubble retention, allowing for cost-effective production and improved measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a compact flow meter design is used, then the device size is reduced, but manufacturing precision deteriorates due to burr formation at transition edges during plastic injection molding

Engineering Contradiction:
Improvedevice sizeVSAvoidtransition edge precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The flow meter housing is divided into two separate parts: the measuring housing and the inflow connection piece. This segmentation allows each component to be manufactured independently with optimized molding processes, avoiding the burr formation issue that occurs when trying to produce a compact integrated housing with tight transition edges.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An intermediary connection structure is introduced between the measuring housing and inflow connection piece. This intermediary design provides a dedicated connection interface that accommodates the transition from inflow to cyclonic flow without creating problematic sharp edges, thus maintaining manufacturing precision while achieving compact dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If plastic injection molding is used for cost-effective production, then manufacturing cost is reduced, but measurement precision deteriorates due to turbulence and air bubble retention at transition edges

Engineering Contradiction:
Improvemanufacturing costVSAvoidflow measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

By segmenting the housing into separate injection-molded parts, the design maintains cost-effectiveness while eliminating the turbulence-causing transition edges. Each part can be optimized for its specific function, with the connection interface designed to minimize flow disturbances.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design accepts the limitations of plastic injection molding (such as draft angles and parting lines) and incorporates them into the design in a way that actually benefits flow characteristics. The connection interface is designed to accommodate molding constraints while promoting smooth flow transition and reducing air bubble retention.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If a compact design with integrated components is used, then device complexity is reduced, but adaptability deteriorates for different applications

Engineering Contradiction:
Improvehousing structure complexityVSAvoidapplication adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The segmented housing design allows the measuring housing to remain a standardized, simple component while the inflow connection piece can be varied to suit different applications. This segmentation maintains low overall complexity while providing high adaptability through modular connection designs.

Inventive Principle:
Principle #1Segmentation

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 design ensures high measuring accuracy even with air pockets, is cost-effective to produce, and adaptable to various applications with precise flow path definition, reducing turbulence and air bubble issues at transition edges.

Implementation Method 1

a secondary housing (14) is provided on the housing cover (8) for a sensor which, e.g. due to the Hall effect, responds to at least one sensor transmitter provided on the impeller

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 2

the outflow connector (7) is centrally formed on a housing cover (8) closing the cup-shaped housing part (3), so that it can drain off the liquid flowing in tangentially in a cyclone-like manner

Methodology Applied
Scientific EffectCyclone separation: Cyclone Separation

Data Source

PatentEP2166316B1Flowmeter for liquids
Publication Date: 2018.09.19 SOCIETE DES PRODUITS NESTLE SA
  • EP2166316B1 patent drawingFigure 1~2
  • EP2166316B1 patent drawingFigure 3~4

AI summary

The flow meter has an inlet flow port (4) tangentially formed at a cylindrical measuring housing in plastic injection molding. A sensor is provided at the housing for determining fluid amount flowing through the housing based on rotation of a wheel blower. An outlet flow port is centrally formed at a housing cover, and the inlet flow port encloses a nozzle tube (18) forming a nozzle channel so that a fluid flows through the flow meter in a cyclonic manner, where the tube is inserted into the inlet flow port and opens corresponding to a direction of the inlet flow port.