Knudsen Pump Fluid Sensing for Portable Electronics

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Solution Overview

Problem

Existing fluid sensing devices in portable electronic devices face challenges with high energy consumption, bulkiness, and noise due to mechanical moving parts, making them unsuitable for mobile devices like smartphones and smartwatches.

Innovation Solution

A motionless fluid pumping mechanism using thermal transpiration, such as a Knudsen pump, which operates without moving parts, reducing energy consumption and size, and is powered by heat sources like batteries or electronic components, allowing for silent and compact fluid movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If mechanical pumps or fans are used to move fluid in portable electronic devices, then fluid can be moved effectively, but energy consumption increases, device size increases, and noise is generated

Engineering Contradiction:

Improvefluid movement capabilityVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent replaces mechanical pumps and fans with a Knudsen pump that uses thermal transpiration - a non-mechanical phenomenon where temperature gradients drive fluid flow through narrow channels or porous media. This substitution eliminates moving parts, reducing energy consumption, device size, and noise while maintaining fluid movement capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the operating parameters by using temperature gradients instead of mechanical forces to drive fluid flow. The Knudsen pump utilizes controlled heating zones to create thermal transpiration effects, transforming the mechanism from mechanical to thermal-based fluid actuation.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If mechanical pumps or fans are used to move fluid, then fluid can be moved effectively, but device size and volume increase

Engineering Contradiction:

Improvefluid movement capabilityVSAvoiddevice volume

Core Design Contradiction:

ProductivityVSVolume of moving object

Solution Approach 1:

By replacing bulky mechanical pumps with a Knudsen pump based on thermal transpiration, the device volume is significantly reduced. The Knudsen pump requires only narrow channels or porous media with heating elements, eliminating the need for large mechanical components, motors, and associated infrastructure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention employs porous media as the core component of the Knudsen pump. The porous structure provides the necessary narrow pathways for thermal transpiration to occur, replacing solid mechanical pump components with a lightweight, compact porous material that achieves the same fluid movement function in much smaller volume.

Inventive Principle:

Principle #31Porous materials

3Productivity

If mechanical pumps or fans are used to move fluid, then fluid can be moved effectively, but noise is generated

Engineering Contradiction:

Improvefluid movement capabilityVSAvoidnoise

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent eliminates noise-generating mechanical components by substituting them with a Knudsen pump that relies on thermal transpiration. Since the Knudsen pump has no moving parts, fans, or mechanical actuators, it operates silently while still achieving effective fluid movement through temperature-driven flow.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If fluid sensors are integrated into portable devices through openings, then fluid analysis is enabled, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvefluid analysis capabilityVSAvoiddevice manufacturing

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention merges the fluid sensor integration with existing device openings (microphone, speaker, or other apertures). By combining multiple functions - fluid sampling, sensing, and acoustic functionality - into shared openings, the device complexity and manufacturing difficulty are reduced while maintaining fluid analysis capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent makes existing device openings serve multiple purposes: they function as acoustic apertures for microphones or speakers and simultaneously as fluid sampling ports for the sensor. This multi-functionality eliminates the need for separate dedicated openings, simplifying device design and manufacturing.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP3470835B1Fluid sensing device for a portable electronic device

Publication Date: 2023.03.22 BOYDSENSE INC

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AI summary

The present invention relates to a fluid sensing device for a portable electronic device, comprising a fluid sensing means configured to analyze a sampling volume; and a fluid moving means comprising a motionless fluid pumping means using thermal transpiration for moving the sampling volume. It also relates to a portable electronic device comprising such fluid sensing device. Using a motionless fluid pumping means, a sampling volume can be moved at low energy consumption and low noise.