PCB-Mounted Flow Tube Layout for Compact Flow Rate Sensing

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Solution Overview

Problem

Conventional flow sensing devices face challenges in reducing size while maintaining functionality, particularly in applications where space is limited, and there is a need for precise flow rate measurement to avoid over- or under-dosing in drug delivery systems.

Innovation Solution

The design incorporates a flow sensing device with a housing, a printed circuit board assembly (PCBA), and a flow tube, where the fluid inlet and outlet tubes protrude through aligned through-holes on opposite sides of the PCBA, reducing the overall height and enabling precise flow measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the flow tube outlets are positioned on the same side of the housing as the inlet, then the device structure is simpler, but the overall device height increases and positioning flexibility is reduced

Engineering Contradiction:
Improvedevice heightVSAvoidassembly complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent transitions from a planar arrangement where all tube outlets are on the same side to a three-dimensional configuration where outlets are distributed on opposite sides of the housing. This dimensional change allows the flow tube to be routed through the housing interior, significantly reducing the overall device height while maintaining functional integrity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The flow tube is nested within the housing structure, with the tube routing through the interior cavity of the housing. This nesting approach allows the flow tube to be contained within the existing housing volume rather than extending externally, thereby reducing the overall device footprint and height.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Length of moving object

If the flow tube is routed through the housing interior, then the overall device height is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvedevice heightVSAvoidtube positioning precision
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The housing is designed with pre-formed routing channels or guides that specify the exact path the flow tube should follow. These preliminary structural features are created during housing manufacturing, establishing precise reference points that simplify the subsequent tube installation process and ensure accurate positioning without requiring high-precision manual assembly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediate positioning features such as mounting tabs, clips, or guide pins that facilitate the accurate placement of the flow tube within the housing. These intermediary elements act as mediators between the tube and housing, providing mechanical guidance and securing the tube in its precise routing position without requiring direct high-precision machining of all components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the flow sensing device is made more compact, then it can fit into smaller devices and improve positioning flexibility, but the flow measurement precision may be compromised

Engineering Contradiction:
Improvepositioning flexibilityVSAvoidflow rate measurement precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The flow tube is designed with differentiated local characteristics: the section passing through the housing interior is optimized for compact routing, while the outlets extending through the housing walls provide adequate space for fluid connection. This local quality differentiation allows the tube to navigate the compact housing volume while maintaining sufficient external interfaces for accurate flow measurement.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By routing the flow tube through the third dimension (inside the housing cavity rather than along the exterior surfaces), the design achieves compactness without compromising the functional requirements. The tube can be positioned to maintain optimal flow characteristics while the housing walls provide stable mounting points for precise measurement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This configuration allows for a compact flow sensing device that can accurately measure flow rates, fitting into smaller devices and improving positioning flexibility, thereby reducing the risk of over- or under-dosing in drug delivery systems.

Implementation Method 1

a sensing element disposed on the first major surface of and in electronic communication with the PCBA... The flow path is disposed proximate the sensing element such that at least a portion of the flowing media makes direct contact with the sensing element

Methodology Applied
Scientific EffectFlow sensing:

Data Source

PatentEP4435387B1Flow sensing device and associated method
Publication Date: 2026.02.04 HONEYWELL INTERNATIONAL INC
  • EP4435387B1 patent drawingFigure 1~3
  • EP4435387B1 patent drawingFigure 2
  • EP4435387B1 patent drawingFigure 4

AI summary

A flow sensing device is provided. For example, a flow sensing device may include a housing, a printed circuit board assembly (PCBA) having a first major surface and an opposing second major surface, a sensing element disposed on the first major surface, and a flow tube defining a flow path configured to convey a flowing media. The flow tube comprises an elongated main body, a fluid inlet tube, and a fluid outlet tube. The flow tube is disposed such that the elongated main body is proximate the first major surface of the PCBA, the fluid inlet tube protrudes through a first PCBA through-hole to position the opening of the fluid inlet tube proximate the second major surface of the PCBA, and the fluid outlet tube protrudes through a second PCBA through-hole to position the opening of the fluid outlet tube proximate the second major surface of the PCBA.