Rotary Spray Bell Cup Notch Geometry for Fine Droplets at Lower Speed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rotary coating product sprayers face challenges in increasing yield while maintaining droplet homogeneity and quality at lower rotation speeds, as reducing speed can lead to larger droplets and reduced homogeneity.
Innovation Solution
A liquid coating product spray bowl with increased linear density of notches and reduced opening angle, combined with a turbine-driven rotation speed of less than 40,000 rpm and controlled conforming air flow, ensures efficient and homogeneous application of fine droplets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the bowl's rotation speed is reduced to decrease kinetic energy of droplets, then the kinetic energy is reduced, but the homogeneity of droplet cloud and droplet size quality deteriorate
Solution Approach 1:
The circular spray edge is segmented into a high density of notches (at least 4 per mm), dividing the coating product flow into numerous individual droplet streams. This segmentation allows each notch to generate fine, controlled droplets that maintain homogeneity even at lower rotation speeds, resolving the contradiction between reduced kinetic energy and droplet cloud homogeneity.
Solution Approach 2:
The invention changes the geometric parameters of the notches - specifically increasing linear density to ≥4 notches/mm and limiting opening angle to ≤45°. These parameter changes optimize droplet formation characteristics, enabling fine, homogeneous droplets to be produced at lower rotation speeds without sacrificing quality, thus resolving the energy-homogeneity contradiction.
2Loss of energy
If the bowl's rotation speed is reduced to decrease kinetic energy of droplets, then the kinetic energy is reduced, but the droplet size increases
Solution Approach 1:
By segmenting the spray edge into high-density notches, each notch produces a controlled stream of fine droplets. The segmentation effect dominates over the reduced rotation speed, ensuring that droplet size remains fine and suitable for quality coating application even when kinetic energy is reduced.
Solution Approach 2:
The geometric parameters of the notches are optimized to produce fine droplets - with linear density ≥4 notches/mm and opening angle ≤45°. These parameter changes ensure that droplet size remains controlled and fine, preventing droplet coalescence that would occur at lower rotation speeds with conventional notch designs.
3Manufacturing precision
If the opening angle of notches is reduced and linear density is increased, then droplet homogeneity improves, but the cross-section area for coating product flow in each notch decreases
Solution Approach 1:
The total coating product flow is distributed across a high density of notches (≥4 per mm). While each individual notch has reduced flow capacity due to the small opening angle, the cumulative flow capacity of all notches together maintains adequate total throughput while each notch produces homogeneous fine droplets.
Solution Approach 2:
The notch geometry parameters are optimized - linear density increased to ≥4 notches/mm and opening angle reduced to ≤45°. This parameter combination creates a situation where the high number of notches compensates for the reduced individual notch capacity, maintaining overall flow rate while achieving superior droplet homogeneity from each notch.
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 achieves a high yield of fine droplets with good homogeneity and quality coating layer application even at lower rotation speeds, utilizing a combination of notch geometry and controlled air flow to direct droplets effectively.
Implementation Method 1
a droplet of coating product leaves the edge of the bowl with kinetic energy that is directly proportional to the bowl's rotational speed
Implementation Method 2
This conforming air has an aerodynamic effect directed along a generally axial direction relative to the bowl's axis of rotation, thus directing the paint droplets towards the object to be coated
Implementation Method 3
an electrostatic charge applied to the coating product before or after spraying allows the electrostatic effect to be used to direct the coating droplets towards the object to be coated
Data Source
Figure 1
Figure 2A~2B
AI summary
The present invention relates to a liquid coating product spray bowl (6) for integration into a rotary coating product sprayer. The bowl comprises a body (60) centered on a longitudinal axis (X6) and defining an internal radial surface (61) for distributing the coating product to a circular spray edge (63) centered on the longitudinal axis and equipped with notches (66i) formed in the internal radial distribution surface (61) and regularly distributed around its circumference. The linear density (DL66) of the notches (66i) along the circular spray edge (63) is greater than or equal to 4 notches per millimeter. The opening angle (α66) of each notch (66i) is less than or equal to 45°.