Flow Sensor Connection Element for Low-Interference Hot-Wire Measurement

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Solution Overview

Problem

Existing flow sensors with shadow bodies for determining flow direction cause significant pressure drops, especially at larger flow rates, and require accurate electrical signal transmission without interference or loss.

Innovation Solution

A measuring arrangement with a measuring bridge and an electrical connection element that forms plug connections between the bridge and resistance sensors, using a carrier element with equipotential surfaces to connect contact arrangements and reduce transition resistances, allowing for near-patient flow measurement with reduced cable diameter and interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If shadow body is provided in the flow chamber to determine flow direction, then flow direction can be determined, but pressure drop increases significantly

Engineering Contradiction:

Improveflow direction determinationVSAvoidpressure drop

Core Design Contradiction:

Ease of operationVSStress or pressure

Solution Approach 1:

The invention extracts and eliminates the shadow body from the flow chamber design. Instead of using a physical shadow body to create flow direction determination, the patent uses thermal conduction paths between heating and sensing elements that are inherently directional, thus removing the harmful shadow body while preserving the useful flow direction detection function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical shadow body structure with a thermal field-based solution. The directional thermal conduction paths through the support structure substitute for the mechanical shadow body, using thermal physics rather than mechanical obstruction to achieve flow direction determination.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If electrical signals are transmitted over long distances with conventional connections, then signals can reach the measurement bridge, but interference and signal loss increase

Engineering Contradiction:

Improvesignal transmissionVSAvoidinterference and signal loss

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention applies equipotentiality by connecting all support structures to a common potential at the measurement bridge side. This eliminates potential differences between support elements, preventing circulating currents and reducing electromagnetic interference. The common potential reference minimizes signal loss and improves reliability of electrical signal transmission.

Inventive Principle:

Principle #12Equipotentiality

3Ease of manufacture

If multiple separate cable connections are used for resistance sensors, then electrical connections can be established, but cable diameter increases and flexibility decreases

Engineering Contradiction:

Improveelectrical connection setupVSAvoidcable arrangement

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention merges multiple separate cable connections into a single integrated cable assembly. All support structures and sensing elements are connected through combined cable paths that run together, reducing the number of separate cables needed. This simplifies the overall cable arrangement, reduces total cable diameter, and improves flexibility while maintaining all necessary electrical connections.

Inventive Principle:

Principle #5Merging (Combining)

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 minimizes errors in flow rate and direction determination by reducing cable size, interference, and potential differences, ensuring accurate and reliable flow measurements with a more flexible and cost-effective setup.

Implementation Method 1

The carrier element comprises at least one common equipotential surface which electrically conductively connects at least two contact arrangements, of the plurality of electrical contact arrangements, to one another

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

The function of the flow sensor is based on thermal anemometry, in particular in the form of thermal anemometry with a number of hot wires arranged on support elements

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The change in resistance of the hot wire is a measure of the passing gas volume flow

Methodology Applied

Scientific EffectThermal anemometry:

Data Source

PatentUS20260009817A1Measuring arrangement with a connecting element

Publication Date: 2026.01.08 DRAGERWERK AG

AI summary

A measuring arrangement (490) includes a measuring bridge (400) and an electrical connection element (49) for a flow sensor. The flow sensor is configured to measure the flow rate according to the measuring principle of hot-wire anemometry. A number of electrical contact arrangements (45, 46, 47), arranged on a support element (200) with a common equipotential surface (22), are used for electrical contacting of carrier elements (44) and resistance sensors C1 (55), W2 (66), W1 (77).