Electrostatic Nozzle Height Feedback for Uniform Edible Coating
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Solution Overview
Problem
Conventional electrostatic coating systems for fruits and vegetables face challenges with nozzle flow rate variations due to viscosity changes, fixed nozzle positions leading to non-uniform coatings, and thrust-induced drifting of droplets, resulting in uncoated spots and resource wastage.
Innovation Solution
A system with variable height adjustment and pressure sensing for thrust correction, combined with twin-phase air-assisted and forced-liquid flow nozzles, ensures uniform deposition by compensating for viscosity changes and preventing droplet drift through servo-motor controlled nozzle movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional spray coating methods are used to coat fruits and vegetables, then coating coverage can be achieved, but huge amount of edible material is wasted and coating uniformity is poor
Solution Approach 1:
The patent replaces conventional mechanical spray coating systems with an electrostatic coating system that uses electric fields to charge and direct coating droplets. The electrostatic nozzle generates charged droplets that are attracted to the grounded produce, replacing mechanical spray propulsion with electrostatic forces for more precise and uniform coating application
Solution Approach 2:
The patent introduces variable height adjustment capability to the electrostatic nozzle, allowing dynamic change in the distance between the nozzle and produce surface. This parameter adjustment optimizes the electrostatic field distribution and droplet trajectory, ensuring uniform coating coverage while minimizing material waste
2Productivity
If electrostatic nozzle flow rate is increased to improve coating speed, then productivity increases, but thrust created by droplets causes drifting and uncoated spots
Solution Approach 1:
The patent implements variable height adjustment that dynamically adapts the nozzle-to-produce distance based on coating conditions. When coating speed increases and thrust causes drifting, the system automatically adjusts the height to optimize droplet deposition, maintaining coating uniformity while allowing high productivity operation
Solution Approach 2:
The patent incorporates a feedback mechanism where the system monitors coating effectiveness and adjusts nozzle height accordingly. This closed-loop control ensures that even at high flow rates, the droplets deposit uniformly on the produce surface by compensating for thrust-induced drifting through real-time height adjustments
3Device complexity
If nozzle is fixed at one position to simplify the system, then device complexity is reduced, but coating uniformity deteriorates due to inability to adapt to different produce positions
Solution Approach 1:
The patent replaces fixed nozzle positioning with a variable height adjustment mechanism that allows the nozzle to dynamically change its position relative to the produce. This dynamic positioning capability ensures optimal coating uniformity across different produce sizes and positions on the conveyor without requiring complex multi-axis positioning systems
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
Achieves uniform and efficient coating with minimal material usage, ensuring complete coverage and reduced environmental impact by using biodegradable materials, enhancing shelf life and nutritional value of food commodities.
Implementation Method 1
The process of electrostatic coating involves generating a high electric field within the spray nozzle at atomization and charging zone, which imparts charge to liquid jet passing through a charging ring electrode
Implementation Method 2
US4732777A, US3049092 and US3059613 have utilized the electrostatic forces to control the trajectory of charged particulate matter for efficient deposition
Implementation Method 3
variable height for thrust correction through pressure sensing and feedback mechanism
Data Source
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AI summary
The present invention discloses the design and development of an electrostatic coating system comprising of a novel technique of height adjustment through pressure sensing and feedback mechanism in twin-phase air-assisted and forced-liquid flow based electrostatic nozzle(s). Variable height electrostatic edible coating system provides uniform and efficient coating to ensure shelf-life extension, improved nutritional value and enhanced sensory attribute.