Coating Gun Injector Axial Protrusion for Overspray Reduction
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Solution Overview
Problem
Existing coating guns with 'round jet' injectors face challenges in achieving a well-defined impact and good aesthetic appearance when dealing with viscous products, often resulting in the 'overspray' phenomenon due to high-pressure compressed air usage, which is inefficient and ineffective.
Innovation Solution
The method involves calibrating the axial protrusion dimension of the injector with respect to the cap to optimize the impact definition, allowing for a well-defined spray without high-pressure compressed air, and adjusting the impact diameter without altering the air flow rate or pressure, using a gun design that includes an adjustable cap and a minimized 'vortex' air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-pressure compressed air is used in the atomizing air circuit to obtain a fine spray and good aesthetic appearance, then the spray quality is improved, but the overspray phenomenon increases causing ill-defined impact geometry
Solution Approach 1:
The invention changes the geometric parameters of the injector-c cap assembly, specifically the axial protrusion dimension of the injector and the radial dimension of the air gap, to optimize spray pattern definition without relying on high air pressure that causes overspray
Solution Approach 2:
The invention replaces the mechanical approach of using high-pressure air to define the spray boundary with a geometric approach where the physical structure of the injector and cap assembly defines the spray pattern through their dimensional relationships
2Manufacturing precision
If high-pressure compressed air is used to atomize viscous products, then atomization quality is improved, but compressed air consumption increases
Solution Approach 1:
The invention optimizes the air gap dimension and axial protrusion dimension to achieve effective atomization of viscous products with reduced air pressure, thereby decreasing compressed air consumption while maintaining atomization quality
3Manufacturing precision
If the axial protrusion dimension of the injector is not properly calibrated, then the impact definition is poor, but using compressed air under high pressure to compensate causes overspray
Solution Approach 1:
The invention performs preliminary calibration of the axial protrusion dimension during the manufacturing process, establishing the correct geometric relationship between injector and cap before use, thereby eliminating the need for high-pressure air compensation that would cause overspray
Solution Approach 2:
The invention establishes specific parameter ranges for the axial protrusion dimension and air gap dimension that optimize impact definition without requiring high air pressure, thus preventing overspray while achieving good impact definition
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 approach reduces compressed air consumption, minimizes overspray, and allows for efficient application of viscous products with improved aesthetic results and reduced cleaning needs, while maintaining the effectiveness of the 'vortex' air flow in stabilizing the jet.
Implementation Method 1
the gun comprises a so-called spray compressed air circuit, making it possible to expel air in an axial direction around the jet of product. This so-called spray air then shears the jet of product, which makes it possible to atomize the coating product in the form of droplets
Implementation Method 2
the gun sometimes includes a second compressed air circuit, called additional air circuit or 'vortex' air circuit, allowing compressed air to be expelled around the jet of product in a direction substantially orthoradial with respect to the spray axis. In this way, the air is expelled around the product jet in a swirling fashion, which has the effect of stabilizing the product jet
Data Source
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AI summary
This method is used to manufacture a coating application gun. The gun comprises an injector (12) for spraying a round jet along a spray axis (X-X') and a cap (14) arranged coaxially around the injector, this cap being designed to form an air gap around the jet. The method includes a step of dimensioning an axial overhang (d) of the injector (12) relative to the cap (14) as a function of the injector diameter (D). The coating application gun comprises an injector (12) for projecting a round jet along a spray axis (X-X'), and a cap (14) arranged coaxially around the injector, designed to form an air gap around the jet.The injector (12) protrudes axially from the cap (14) and the dimension (d) of axial protrusion of the injector from the cap can be adjusted between a minimum value and a maximum value determined according to the diameter (D) of the injector (12).