Inductive Valve Spindle Positioning for Retrofit Alignment-Free Sensing

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Solution Overview

Problem

Existing valve control systems face challenges in being retrofitted with position sensors, as they are sensitive to magnetic interference and require precise alignment, which can lead to incorrect installation and faulty function.

Innovation Solution

An actuating system featuring a circular-cylindrical inductive sensor that can be attached to the valve's switching spindle without misalignment, using a conductive material for position determination, and a connecting part that engages with the spindle to prevent slippage, ensuring accurate position measurement and resistance to magnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a disc-shaped position sensor with coil and capacitor is attached to the switching spindle, then the valve can be retrofitted with position measurement capability, but it requires correct alignment during assembly which cannot be directly checked and may lead to faulty function

Engineering Contradiction:
Improveretrofit capabilityVSAvoidalignment precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent employs a circular-cylindrical position sensor instead of a disc-shaped sensor. This cylindrical geometry provides rotational symmetry around the switching spindle, eliminating the alignment problem. The sensor can be mounted in any rotational position and will function correctly, as the measurement capability is invariant to rotation around the spindle axis.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The circular-cylindrical sensor design makes the system self-aligning. The sensor automatically adapts to the correct measurement orientation through its geometric symmetry, without requiring external alignment tools or procedures. The mounting process becomes self-service in terms of alignment, as any rotational position is valid.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If magnets are arranged in the switching spindle for non-contact measurement, then position can be detected by Hall sensors, but the solution is sensitive to magnetic interference fields from solenoid valves or servomotors

Engineering Contradiction:
Improveposition detection accuracyVSAvoidmagnetic interference sensitivity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the magnetic field-based measurement system (Hall sensors detecting magnets) with an inductive measurement system. The circular-cylindrical position sensor uses inductive coupling to detect the position of the switching spindle, which is made of electrically conductive material. This substitution eliminates sensitivity to magnetic interference from solenoid valves and servomotors, as inductive sensing is not affected by magnetic fields.

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

Solution Approach 2:

The patent changes the physical parameter used for measurement from magnetic field interaction to inductive coupling. By using the electrical conductivity of the switching spindle material and inductive sensing, the system achieves position detection without relying on magnetic fields, thereby avoiding interference from magnetic sources in the environment.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a position sensor is attached to the switching spindle during manufacture, then the valve has integrated position measurement, but it cannot be used for retrofitting existing valves

Engineering Contradiction:
Improveintegration precisionVSAvoidretrofit applicability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The circular-cylindrical position sensor is designed with a universal mounting approach that works for both new valve manufacturing and retrofitting existing valves. The sensor can be attached to the switching spindle through a standardized connecting part that engages with the spindle, allowing the same sensor design to serve dual purposes: integrated manufacturing and field retrofitting.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent divides the positioning system into separate modular components: the circular-cylindrical position sensor, the connecting part for attachment to the switching spindle, and the evaluation unit. This segmentation allows the sensor to be independently mounted on existing valves during retrofitting, without requiring modification of the valve body itself, thus enabling both manufacturing integration and retrofitting applications.

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 system allows for reliable and accurate position measurement of the valve, preventing misalignment and interference issues, making it suitable for both manufacturing and retrofitting, with a robust design that ensures precise control of the valve's position.

Implementation Method 1

A movement of the switching spindle parallel to the inductive sensor can then be measured inductively by the presence of the electrically conductive material in the position transmitter

Methodology Applied
Scientific EffectInductive sensing: Electromagnetic Induction

Data Source

PatentEP3683479B1Positioning system for a valve
Publication Date: 2021.02.24 CONTELEC
  • EP3683479B1 patent drawingFigure 1
  • EP3683479B1 patent drawingFigure 2~3
  • EP3683479B1 patent drawingFigure 4~5

AI summary

An actuating system (10) for a valve (20) has an outer housing (11). A receiving area (12) for receiving a switching spindle (21) of the valve (20) extends within the outer housing (11). At least one inductive sensor extends parallel to the receiving area (12). The actuating system further comprises at least one substantially circular cylindrical position sensor (40) made of an electrically conductive material and having a channel (43) extending along its longitudinal axis. This channel is configured to receive the switching spindle (21) of the valve (20).