Ultrasonic Coating Atomizer With Electrostatic Droplet Separation

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Solution Overview

Problem

Current rotary bell applicators in high-volume automotive painting produce droplets with wide size distribution and inconsistent momentum, requiring high voltage and large amounts of electricity, leading to overspray and uneven coating appearance, while ultrasonic atomizers suffer from droplet coalescence due to non-uniform spacing and velocities.

Innovation Solution

An ultrasonic atomizer with a nozzle and electrode system that electrostatically charges gas or droplets to control droplet spacing and momentum, using piezoelectric transducers to generate fine droplets perpendicular to the nozzle, and electrostatically charged gas to prevent coalescence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If ultrasonic atomization is used to produce narrow particle size droplets, then droplet size uniformity is improved, but droplet coalescence occurs due to non-uniform spacing and velocities

Engineering Contradiction:

Improvedroplet size uniformityVSAvoiddroplet spacing uniformity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A shaping gas flow is introduced as an intermediary medium between the ultrasonic atomizer and the substrate. This gas flow serves multiple functions: it spaces the droplets uniformly, directs them toward the substrate, and prevents coalescence by maintaining separation between droplets during transit.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies voltage potentials to electrode arrays positioned downstream of the atomizer to electrostatically charge and manipulate droplet trajectories. By adjusting voltage parameters, the system compensates for variations in droplet velocity and spacing, ensuring uniform distribution and preventing coalescence.

Inventive Principle:

Principle #35Parameter changes

2Force

If rotary bell applicators use high voltage to redirect droplets, then droplet attraction to substrate is improved, but energy consumption increases

Engineering Contradiction:

Improvedroplet attraction forceVSAvoidelectricity consumption

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The patent replaces the high-voltage electrostatic attraction system of rotary bells with a lower-voltage electrode array that works in conjunction with shaping gas flow. The gas flow provides the primary droplet direction and spacing control, allowing reduced voltage operation while maintaining effective droplet delivery to the substrate.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If shaping gas is applied to redirect droplets, then droplet direction control is improved, but droplet coalescence may occur

Engineering Contradiction:

Improvedroplet redirection capabilityVSAvoiddroplet separation

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The shaping gas acts as a controlled intermediary that simultaneously achieves droplet redirection and spacing. By carefully controlling gas flow parameters (velocity, pressure, distribution), the system directs droplets toward the substrate while maintaining sufficient inter-droplet spacing to prevent coalescence.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent incorporates electrode arrays with controllable voltage potentials that can be adjusted based on operating conditions. This feedback mechanism allows real-time compensation for droplet coalescence tendencies by applying electrostatic forces to separate coalescing droplets or adjust their trajectories.

Inventive Principle:

Principle #23Feedback

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 system achieves uniform droplet distribution and improved coating consistency by preventing droplet coalescence and reducing energy consumption, resulting in a more efficient and uniform coating application process.

Implementation Method 1

using piezoelectric transducers to generate fine droplets perpendicular to the nozzle

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

electrostatically charges gas or droplets to control droplet spacing and momentum

Methodology Applied

Scientific EffectElectrostatic charging: Electrostatics

Implementation Method 3

electrostatically charged gas to prevent coalescence

Methodology Applied

Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Data Source

PatentUS12420296B2Ultrasonic atomizer for applying a coating to a substrate with electrostatic charge to prevent droplet coalescence during atomization

Publication Date: 2025.09.23 FORD MOTOR CO

AI summary

An atomizer for applying a coating to a substrate includes a nozzle and at least one electrode. The nozzle defines a plurality of apertures. The nozzle includes a nozzle plate, a nozzle body, and an actuator. The nozzle plate defines the apertures. The nozzle body and an inner side of the nozzle plate define a reservoir in fluid communication with the first apertures. The actuator is configured to vibrate the nozzle plate to eject droplets of a liquid from the reservoir through the first apertures. The at least one electrode is configured to directly or indirectly electrostatically charge the droplets with a charge that repels the droplets from each other to reduce coalescence of the droplets before the droplets reach the substrate.