Electrostatic Spray Nozzle Assembly for High Flow Rate Drying
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Solution Overview
Problem
Existing electrostatic spray nozzle assemblies face challenges in achieving high flow rates while maintaining fine droplet sizes and avoiding contact between degradable plastic components and solvents, which leads to inefficiencies and increased costs in spray drying applications.
Innovation Solution
The development of an electrostatic spray nozzle assembly with a cluster head design and internal mix capabilities, utilizing conductive materials and a specific nozzle configuration to achieve high flow rates, fine droplet sizes, and protection of non-metallic components from solvent contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external mix spray nozzle assemblies are used, then fine droplet sizes can be achieved at low flow rates, but the liquid discharge orifice must be increased in diameter to reach higher flow rates which causes droplet sizes to increase
Solution Approach 1:
The spray nozzle assembly divides the liquid flow into multiple streams through a multi-orifice liquid discharge component, allowing each individual orifice to maintain a small diameter for fine droplet production while the collective assembly achieves high total flow rates. The liquid is segmented into multiple parallel flows rather than a single large stream.
Solution Approach 2:
The invention transitions from a single-orifice design to a multi-orifice array configuration, adding spatial dimensionality to the liquid discharge. Multiple small orifices are arranged in specific patterns (e.g., radial, axial, or circumferential arrangements) to collectively deliver high flow rates while maintaining fine droplet sizes from each individual orifice.
2Productivity
If larger spray nozzle discharge orifices are used to increase flow rate, then spraying capacity increases, but droplet sizes become too large to dry adequately in the dryer chamber
Solution Approach 1:
The liquid discharge component incorporates multiple small orifices instead of a single large orifice, segmenting the total liquid flow into multiple fine streams. This segmentation allows the system to achieve high spraying capacity through increased flow volume while maintaining small droplet sizes from each individual orifice that can be adequately dried in the chamber.
Solution Approach 2:
The invention changes the geometric parameters of the liquid discharge component by using multiple small orifices with specific diameter ranges (e.g., 0.02-0.1 inches) rather than a single large orifice. This parameter change enables the system to optimize droplet size for drying while increasing total flow capacity through the multiplicity of orifices.
3Adaptability or versatility
If degradable plastic components are used in the spray nozzle assembly, then non-metallic material benefits are achieved, but solvents attack and degrade such materials
Solution Approach 1:
The invention introduces solvent-resistant materials (such as metal or chemically resistant polymers) as intermediary components that come into contact with the liquid stream, while degradable plastic components are positioned in non-contact zones. This intermediary arrangement allows the system to benefit from non-metallic materials in appropriate locations while protecting degradable components from solvent attack through the liquid stream path design.
Solution Approach 2:
The invention extracts or removes degradable plastic components from zones where they would contact the liquid stream, placing them only in areas where they do not interact with solvents. This extraction of degradable materials from harmful environments allows the system to use non-metallic materials where beneficial while preventing degradation by eliminating solvent exposure to those components.
4Manufacturing precision
If internal mix spray nozzle assemblies are used, then multistage liquid breakup produces very fine liquid particles, but higher liquid pressures preclude the use of low pressure peristaltic pumps
Solution Approach 1:
The invention uses compressed gas (pneumatic assistance) to atomize the liquid stream as it exits the nozzle, enabling fine liquid particle production through gas-liquid interaction rather than relying solely on high liquid pressure. This pneumatic atomization mechanism allows the system to achieve very fine liquid particles while operating at low liquid pressures compatible with peristaltic pumps.
Solution Approach 2:
The invention changes the operating pressure parameters by designing the liquid discharge component and atomization system to function effectively at low pressures (e.g., below 10 psi liquid pressure). This parameter change enables the use of low-pressure peristaltic pumps while still achieving fine liquid particle production through optimized orifice geometry and pneumatic assistance rather than high-pressure forcing.
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 solution enables the production of high-flow-rate, fine liquid particle sprays at low pressures, reducing the need for extensive drying chambers and minimizing the risk of component degradation, thereby enhancing operational efficiency and cost-effectiveness in spray drying processes.
Implementation Method 1
electrostatically charging fluids to facilitate fine liquid particle breakdown and distribution
Implementation Method 2
atomizing with non-air gases, such as hydrogen
Data Source
AI summary
An electrostatic sprayer operable at high flow rates and low pressures particularly suitable for spray drying. The sprayer includes an elongated body having a downstream spray nozzle assembly through which electrically charged liquid is directed via a central feed tube within the nozzle body and atomizing air is supplied via an annular passage about the liquid feed tube. In one embodiment, the nozzle assembly is an external mix cluster head spray nozzle assembly having a plurality of circumferentially spaced metallic spray tips. In another embodiment, the spray nozzle is an internal mix nozzle assembly having a spray tip with an internal mixing chamber for atomizing liquid prior to discharge.