Balanced Flapper Electro-Pneumatic Converter

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Solution Overview

Problem

Existing electro-pneumatic converters rely on spring stiffness and friction forces, which are susceptible to environmental factors and orientation changes, leading to deviations in the correlation between fluid pressure and electrical signal, and are costly to manufacture due to tight tolerances.

Innovation Solution

A balance beam electro-pneumatic converter with a freely rotating pivot and bearings, where the flapper is unconstrained by a spring, and a counterweight balances the flapper to regulate fluid pressure, using a coil and magnet assembly to align and stabilize the flapper, and a shim to ensure flat contact with the nozzle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a spring is used to counter the flapper weight, then zero pressure correlates with zero current, but the spring stiffness depends on environmental factors such as temperature and fatigue causing correlation drift

Engineering Contradiction:
Improvesignal-pressure correlation accuracyVSAvoidcorrelation stability under environmental variations
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the spring-based counterweight system with a gravitational counterweight system. A counterweight member is positioned on the balance beam such that its gravitational force exactly balances the flapper weight, creating a frictionless equilibrium point at zero pressure. This eliminates the environmental sensitivity of spring stiffness while maintaining the zero-pressure correlation accuracy.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent replaces the elastic mechanical system (spring) with a gravitational mechanical system (counterweight). The spring's elastic force, which varies with temperature and fatigue, is substituted by the constant gravitational force of a counterweight, providing stable and predictable balancing force regardless of environmental conditions.

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

2Ease of operation

If a screw is used to retain the flapper, then the flapper is held in position, but friction forces between the screw and flapper impede movement and change due to environmental factors

Engineering Contradiction:
Improveflapper positioningVSAvoidfriction force consistency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the screw-retention mechanical system with a magnetic retention system. A magnet is positioned to hold the flapper in the desired position without physical contact, eliminating friction forces entirely. The magnetic force can be precisely controlled to provide the necessary holding force without the sliding friction that occurs with screw mechanisms.

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

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the retention mechanism and the flapper. Instead of direct mechanical contact through a screw, the magnetic field acts as a non-contact intermediary to hold the flapper in position, eliminating the friction interface while maintaining positioning capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If tight tolerances are used for flapper manufacturing to ensure proper alignment, then signal-pressure correlation is accurate, but manufacturing costs are prohibitively expensive

Engineering Contradiction:
Improvesignal-pressure correlation accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent divides the alignment function into separate components: the balance beam provides mechanical alignment, the counterweight provides gravitational balancing, and the magnet provides positional retention. This segmentation allows each component to be manufactured with standard tolerances while achieving accurate overall alignment, eliminating the need for prohibitively expensive tight-tolerance flapper manufacturing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a magnet as an intermediary alignment mechanism. Instead of relying on precise mechanical alignment of the flapper itself, the magnet serves as an adjustable intermediary that can be positioned to achieve the correct flapper orientation and gap, allowing standard-tolerance components to be assembled into a precision system.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution maintains accurate signal-pressure correlation across various orientations and environmental conditions, reduces manufacturing costs, and minimizes the impact of temperature and friction, ensuring reliable and repeatable fluid pressure regulation.

Implementation Method 1

The pivot is a freely rotating pivot with bearings

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the flapper is balanced about the pivot

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 3

using a coil and magnet assembly to align and stabilize the flapper

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP3047154B1Electro-pneumatic converter with balanced flapper
Publication Date: 2021.12.15 NORGREN LTD
  • EP3047154B1 patent drawingFigure 1~2A
  • EP3047154B1 patent drawingFigure 2B
  • EP3047154B1 patent drawingFigure 3~4

AI summary

A balance beam electro-pneumatic converter (100, 400) adapted to couple to a conduit with a fluid is provided. The balance beam electro-pneumatic converter (100, 400) includes a nozzle (184) adapted to fluidly couple to the conduit, and a flapper (130) rotatably coupled to the nozzle (184) via a pivot (140) wherein the flapper (130) is adapted to regulate a pressure of the fluid and balance about the pivot (140).