Spray Gun Common Gas Inlet for Thin Film Atomization
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Solution Overview
Problem
Conventional spray guns are not well-suited for applying thin film coatings with a thickness of ≤40 microns, such as nano paints and varnishes, due to imbalance and user fatigue issues, and struggle with fluid atomization when spraying viscous materials.
Innovation Solution
A spray gun design with a common gas inlet dividing into separate first and second gas conduits, along with a primary valve and regulator valves, reduces weight imbalance, allows for precise control of gas flow, and maintains laminar airflow, enabling efficient atomization and fine-tuning of spray characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dual gas inlets with regulators and gauges are provided, then gas flow control capability is improved, but weight imbalance and user fatigue worsen
Solution Approach 1:
The patent combines two separate gas inlet systems into a single common gas inlet that supplies both the gas outlet and horn outlet. This merging eliminates the need for dual regulators and gauges, reducing overall weight and improving balance while maintaining the capability to independently control gas flow to each outlet through a single regulator system.
Solution Approach 2:
The common gas inlet serves multiple functions by distributing pressurized gas to both the gas outlet (for atomization) and horn outlet (for droplet shaping). This multi-functional design consolidates what would traditionally require separate gas supply systems, reducing complexity and improving ergonomics while preserving full control capability.
2Quantity of substance
If gas flow rate is increased to compensate for siphoning effect, then gas flow to horn outlet is improved, but fluid atomisation worsens due to turbulence
Solution Approach 1:
The patent segments the gas flow path into two separate conduits: one leading to the gas outlet for atomization and another leading to the horn outlet for droplet shaping. This segmentation prevents the siphoning effect where gas flow to one outlet compromises the other, allowing optimized gas flow rates for each function without mutual interference.
Solution Approach 2:
The patent changes the flow parameters by using a common gas inlet with a single regulator that can be adjusted to maintain pressures at 15 psi or less. This parameter control prevents turbulence while ensuring adequate gas flow to both outlets, optimizing atomization quality without requiring excessive gas flow rates.
3Manufacturing precision
If gas pressure is increased to improve atomisation, then fluid atomisation is improved, but turbulence increases beyond laminar flow
Solution Approach 1:
The patent optimizes gas pressure parameters by limiting the system to 15 psi or less through a common regulator. This parameter control maintains laminar flow conditions while achieving adequate atomization through the segmented conduit design that prevents pressure loss and turbulence.
Solution Approach 2:
The patent uses small bore holes at the gas outlet (air cap annulus) that replicate the function of larger openings but maintain laminar flow by controlling velocity and pressure. These copied flow paths achieve atomization without the turbulence that would result from higher pressure through larger openings.
4Manufacturing precision
If thin film coatings are applied, then coating precision is improved, but user control capability worsens due to manual hose holding
Solution Approach 1:
The patent merges the gas supply system into a balanced, single-inlet configuration that eliminates the need for manual hose holding. This consolidation improves ergonomics and frees both hands for operating body-mounted controls, enhancing the ability to fine-tune spray characteristics for uniform thin film application.
Solution Approach 2:
The balanced spray gun design with common gas inlet is self-balancing and requires no manual compensation by the user. The system automatically maintains proper balance without requiring the user to hold hoses, allowing full focus on precision control of spray parameters for thin film coating application.
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 design improves user ergonomics, reduces fatigue, and achieves better fluid atomization and uniform coating thickness, even with viscous fluids, by maintaining gas flow pressures at 15 psi or less, preventing turbulence and ensuring a smooth finish.
Implementation Method 1
The reduction in cross-sectional area causes a gas pressure drop at the gas outlet (also known as the air cap annulus). A discernible improvement in fluid atomisation has been observed as a consequence of the pressure drop
Implementation Method 2
a second gas conduit within the main body connected between a gas inlet and the horn outlet
Implementation Method 3
a common gas inlet is provided for the first and second gas conduits and is connectable to an external pressurised gas source
Implementation Method 4
when spraying more viscous fluids, the presence of small bore holes at the gas outlet (air cap annulus) results in non-laminar airflow at pressures exceeding approximately 15 psi (circa. 103 kPa). The resulting turbulence increases with increasing pressure.
Data Source
AI summary
The invention relates to a low energy spray gun for spraying thin film materials with a thickness of <40 microns such as high performance, thin viscosity nano-paints, lacquers, varnishes and the like. The spray gun comprises a main body (12) having a fluid inlet (14a) connected to an external fluid source (not shown) and a fluid outlet nozzle (16a). Gas outlets (16b-d) on the main body carry entrained fluid droplets emitted from the fluid outlet (14a) the shape of which are controlled by horn outlets (24) positioned beyond the fluid outlet (14a) and gas outlets (16b-d). First and second gas conduits (20, 22) are connected between a common gas inlet (18) and gas outlets (16b-d) and horn outlets (24) respectively. The cross-sectional area of a portion of the first gas conduit (20) is reduced relative to that of the second gas conduit (22) thus creating a pressure drop and a discernible improvement in fluid atomisation.