Piezo Pump Diaphragm Pressure Equalization

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Solution Overview

Problem

Piezo pumps in pressurized circuits face challenges with seal integrity due to vibrations and pressurized fluid, leading to potential leakages between the diaphragm and the pump chamber wall, and existing solutions do not adequately address the risk of hydraulic short circuits in series connections.

Innovation Solution

The use of a pressure chamber connected to a pressure source, either through a feeding or discharge line, to equalize pressure across the piezo pump diaphragm, reducing the risk of leakages and hydraulic short circuits by minimizing pressure differences and requiring fewer connections, and the configuration of piezo pumps in series or parallel to manage pressure fluctuations and increase delivery capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the piezo pump operates in a pressurized circuit, then the pump can effectively move fluid under pressure, but the seal between the piezo pump diaphragm and the pump chamber wall becomes compromised due to vibrations and pressure, leading to potential leakages

Engineering Contradiction:
Improvepump performanceVSAvoidseal integrity
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent introduces a compensation chamber that applies a counter-pressure force to the piezo pump diaphragm from the opposite side. This counterweight effect balances the pressure differential across the diaphragm, reducing the net force that causes leakage while maintaining the diaphragm's pumping function. The compensation chamber is connected to a compensation line that provides the necessary counter-pressure.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The compensation chamber acts as an intermediary element between the pressure source and the piezo pump diaphragm. It mediates the pressure forces by distributing the counter-pressure uniformly across the diaphragm's active area, thereby protecting the seal interface without interfering with the pumping action.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a pressure chamber is connected to a separate pressure source, then the pressure difference over the piezo pump diaphragm is reduced, but the device complexity increases due to additional connections and components

Engineering Contradiction:
Improveleakage preventionVSAvoidnumber of connections
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the compensation chamber with the pump chamber structure, using the same housing and diaphragm assembly. The compensation line is integrated into the existing fluid circuitry, eliminating the need for separate pressure sources and reducing the overall number of external connections required.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The compensation chamber serves multiple functions: it provides counter-pressure to prevent leakage, maintains structural integrity of the diaphragm assembly, and can be integrated with the existing pump housing. This multi-functionality reduces the need for additional separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stress or pressure

If multiple piezo pumps are connected in series to achieve increased pressure difference, then the pressure difference is amplified, but the risk of hydraulic short circuit increases due to more potential failure points

Engineering Contradiction:
Improvepressure differenceVSAvoidshort circuit risk
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The compensation chamber provides a protective buffer that prevents pressure differential-induced failures before they can lead to hydraulic short circuits. By maintaining balanced pressure across each diaphragm, the system reduces the stress that could cause seal failures or component breakdown, thereby cushioning against potential short circuit scenarios.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Productivity

If the piezo pump diaphragm vibrates at high frequency, then the pump action is effective, but the seal between the diaphragm and surrounding wall becomes more difficult to maintain

Engineering Contradiction:
Improvepump action effectivenessVSAvoidseal stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The compensation chamber provides a stabilizing counter-pressure that counteracts the dynamic forces generated by high-frequency vibrations. This counterweight effect maintains the diaphragm in a more stable equilibrium position, reducing the amplitude of vibrations at the seal interface and improving seal stability without compromising pump effectiveness.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 significantly reduces the risk of leakages and hydraulic short circuits while maintaining effective pressure equalization and increasing the overall delivery capacity of the piezo pump system.

Implementation Method 1

the piezo pump diaphragm is the driving element which, when connected to an alternate current, vibrates

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The pressure in the pressure chamber at least partially compensates the pressure in the pump chamber, as a result of which the pressure difference over the piezo pump diaphragm is reduced

Methodology Applied
Scientific EffectPressure compensation: Pascal's Law

Data Source

PatentEP2930363B1Piezoelectric pump assembly and pressurised circuit provided therewith
Publication Date: 2020.06.10 STICHTING NAT LUCHTEN RUIMTEVAART LABUM
  • EP2930363B1 patent drawingFigure 1~2
  • EP2930363B1 patent drawingFigure 3~7
  • EP2930363B1 patent drawingFigure 5~6

AI summary

A piezoelectric pump for use in a pressurised circuit is provided, comprising a pump chamber (5) with an inlet (6) provided with a one way inlet valve (7), for connection to a feeding line (8) of the pressurised circuit and an outlet (9) provided with a one way outlet valve (10), for connection to a discharge line (11) of the pressurised circuit and a pump diaphragm (12) closing one end of the pump chamber (5). A pressure chamber (15) is defined at the side of the pump diaphragm (12) facing away from the pump chamber (5), wherein said pressure chamber (15) is connected to a pressure source, which may be the feeding line (8).