Capacitive Fluid Pump Sensor Eliminates Mechanical Wear

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Solution Overview

Problem

Conventional fluid pumps with electromechanical sensors face limitations due to moving components' limited lifespan, increased bulk, sensitivity to pollution, and reduced portability, necessitating an improved sensing mechanism for fluid flow and pressure monitoring.

Innovation Solution

A fluid pump utilizing a capacitance sensor with a monitoring chamber filled with gas, where fluid pressure displaces gas, allowing electronic determination of operational modes without mechanical components, combined with a current sensor for flow detection, enabling complete electronic control and reduced sensitivity to pollution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If electromechanical sensors are used to detect operational parameters, then automatic operation mode is enabled, but moving components reduce reliability and increase bulk

Engineering Contradiction:
Improveautomatic operation modeVSAvoidproduct reliability
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent replaces electromechanical sensors with capacitive sensors that have no moving parts. The capacitive sensor uses electrical fields to detect fluid presence and pressure, eliminating mechanical components while maintaining automatic operation capability through electronic detection of operational parameters.

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

Solution Approach 2:

The patent introduces a diaphragm as an intermediary element that transmits fluid pressure to the capacitive sensor without direct mechanical contact between the fluid and the sensor electronics. This diaphragm allows pressure detection while maintaining isolation between the fluid environment and sensitive electronic components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Extent of automation

If electromechanical sensors are used to detect operational parameters, then automatic operation mode is enabled, but footprint increases reducing portability

Engineering Contradiction:
Improveautomatic operation modeVSAvoidfootprint
Core Design Contradiction:
Extent of automationVSVolume of moving object

Solution Approach 1:

The patent replaces bulky electromechanical sensors with compact capacitive sensors that use electrical field detection. This substitution dramatically reduces the sensor size and overall pump footprint while preserving automatic operation functionality through electronic parameter detection.

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

Solution Approach 2:

The patent integrates the capacitive sensor electrodes and monitoring chamber directly into the pump housing structure, nesting the sensing function within existing components. This integration eliminates separate sensor housings and reduces overall device volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Difficulty of detecting and measuring

If electromechanical sensors are used to detect operational parameters, then sensing capability is provided, but sensitivity to pollution reduces usability

Engineering Contradiction:
Improvesensing capabilityVSAvoidsensitivity to pollution
Core Design Contradiction:
Difficulty of detecting and measuringVSObject-affected harmful factors

Solution Approach 1:

The patent uses a diaphragm as an intermediary that isolates the capacitive sensor from direct contact with the fluid. The diaphragm transmits pressure information while preventing debris, suspended particles, and other pollutants from reaching and damaging the sensor electronics, thereby eliminating sensitivity to pollution.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical sensors that physically interact with fluid with capacitive sensors that detect pressure through electrical fields. This non-contact detection method eliminates sensitivity to fluid pollution while maintaining full sensing capability for operational parameter detection.

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

4Difficulty of detecting and measuring

If electromechanical sensors with moving components are used, then operational parameter detection is achieved, but working life is limited

Engineering Contradiction:
Improveoperational parameter detectionVSAvoidworking life
Core Design Contradiction:
Difficulty of detecting and measuringVSDuration of action of moving object

Solution Approach 1:

The patent replaces electromechanical sensors with capacitive sensors that have no moving parts. Without mechanical components subject to wear, friction, and fatigue, the sensor achieves significantly extended working life and enhanced reliability for continuous operational parameter detection.

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

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 enhances reliability, reduces system cost and bulk, and improves usability by eliminating mechanical components, providing accurate operational mode recognition and real-time pressure indication, while allowing remote monitoring and improved frost warning capabilities.

Implementation Method 1

a capacitance sensor configured to generate a second signal indicative of capacitance between the pair of electrodes

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The dielectric has a first part made of an insulative material and a second part made of a fluid having a level that changes with respect to the insulative material which causes a change in the capacitance of the capacitor

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 3

a diaphragm fluidly coupled to the fluid channel. The diaphragm is adapted to move within the monitoring chamber based on the fluid pressure within the diaphragm

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4004374B1Fluid pump
Publication Date: 2023.06.21 HUSQVARNA AB
  • EP4004374B1 patent drawingFigure 1
  • EP4004374B1 patent drawingFigure 2A~2C
  • EP4004374B1 patent drawingFigure 3

AI summary

A fluid pump (100) includes a fluid inlet (104), a fluid channel (108), a fluid outlet (106), a motor (114), a pair of electrodes (128), a capacitance sensor (124), and a current sensor (120). The fluid pump (100) is configured to monitor a first signal and a second signal. The fluid pump (100) is also configured to be controlled based on at least one of the first signal and the second signal. The capacitance sensor (124) includes a monitoring chamber (126) fluidly coupled to the fluid channel (108). The monitoring chamber (126) is at least partially filled with gas. The monitoring chamber (126) allows the gas to be at least partially displaced by the fluid flowing into the monitoring chamber (126) from the fluid channel (108) based on an operational mode of the fluid pump (100). The pair of electrodes (128) is associated with the monitoring chamber (126). The second signal between the pair of electrodes (128) is indicative of a fluid pressure within the fluid channel (108).