Piezoelectric Suction Device Phase Detection Control

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Solution Overview

Problem

Existing suction devices using piezoelectric elements for fluid suction face challenges in accurately detecting suction pressure without pressure sensors, leading to potential skin or mucosa damage from excessive suction and inefficiencies in fluid collection due to non-sucked states.

Innovation Solution

A suction device incorporating a piezoelectric pump with a detection unit to measure the phase difference between current and voltage, allowing for accurate suction pressure control without a pressure sensor, and a control unit to manage drive voltage based on this phase difference to prevent excessive suction and detect non-sucked states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pressure sensor is provided to detect suction pressure, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvesuction pressure detection accuracyVSAvoiddevice configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses the piezoelectric element itself as an intermediary to detect suction pressure. By measuring the phase difference between the drive voltage and the current flowing through the piezoelectric element, the system indirectly detects suction pressure without requiring a separate pressure sensor. This mediator approach resolves the contradiction by using an existing component for dual purposes (suction generation and pressure detection).

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The piezoelectric element is designed to serve multiple functions: it acts as both the suction pump actuator and the pressure detection sensor. The same element that generates suction through piezoelectric vibration also provides pressure information through its electrical characteristics (phase difference between voltage and current). This multi-functionality eliminates the need for additional pressure sensing components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Use of energy by moving object

If piezoelectric element output increases with self-heat generation, then power efficiency is improved, but harmful factors increase due to excessive suction pressure

Engineering Contradiction:

Improvepower efficiencyVSAvoidskin or mucosa damage from excessive suction

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The system continuously monitors the phase difference between drive voltage and current through the piezoelectric element, which reflects the suction pressure. When the suction pressure approaches dangerous levels (indicating excessive suction), the control unit adjusts or stops the drive voltage to prevent skin or mucosa damage. This feedback mechanism ensures safe operation while allowing efficient power utilization.

Inventive Principle:

Principle #23Feedback

3Device complexity

If suction pressure is estimated from current consumption, then device complexity is reduced, but measurement precision deteriorates under varying drive conditions

Engineering Contradiction:

Improvedetection unit simplicityVSAvoidsuction pressure estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

Instead of using simple current consumption magnitude, the patent utilizes the phase difference parameter between voltage and current, which changes in response to suction pressure conditions. This parameter change approach provides accurate pressure information that is insensitive to variations in drive voltage amplitude or frequency, resolving the precision issue while maintaining simple device architecture.

Inventive Principle:

Principle #35Parameter changes

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

Enables precise control of suction pressure, preventing damage and ensuring efficient fluid collection by simplifying the device configuration and reducing noise, while informing users of suction states to optimize operation.

Implementation Method 1

The piezoelectric pump includes a piezoelectric element configured to vibrate when a drive voltage is applied thereto, and is configured to suck the fluid via the suction portion by vibrating the piezoelectric element

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The detection unit is configured to detect a phase difference between a current flowing through the piezoelectric element and the drive voltage for the piezoelectric element

Methodology Applied

Scientific EffectPhase difference detection:

Data Source

PatentUS10124096B2Suction device

Publication Date: 2018.11.13 MURATA MFG CO LTD

AI summary

A suction device (10) includes: a suction portion (11) that sucks an external fluid; a piezoelectric pump (21) that includes a piezoelectric element (22) vibrating when a drive voltage is applied thereto and sucks the fluid via the suction portion (11) by vibration of the piezoelectric element (22); a detection circuit (32) that detects a phase difference between a current flowing through the piezoelectric element (22) and the drive voltage for the piezoelectric element; and a control unit (33) that performs a process on the basis of the phase difference detected by the detection circuit (32).