Delavan SNA™ Siphon Type Air Atomizing Nozzles: How they Work

Multiphase Flow & Internal Atomization Geometry

The SNA™ series utilizes a two-fluid, internally mixing pneumatic design that relies on low-pressure compressed air as the energy source to lift, shear, and atomize higher-viscosity fluids without requiring high-pressure hydraulic pumping systems:

• Pneumatic Lift Mechanics (Venturi Principle): High-velocity compressed air is introduced coaxially through the center of the nozzle. This localized velocity spike generates a controlled pressure drop (vacuum) at the internal intersection of the fluid paths, creating the static suction head required to draw the medium or heavy oil upward through the fuel line.
• Energy Transfer & Internal Shearing: The siphoned fuel intersects the low-pressure air stream within a dedicated internal mixing chamber. Rather than relying on a restrictive hydraulic orifice to break apart the fluid, the kinetic energy of the compressed air physically shears the high-viscosity fuel.
• Two-Phase Solid Cone Distribution: This internal momentum transfer shreds the liquid boundary layer into an exceptionally fine, homogenous, two-phase mixture. As the mixture expands past the discharge orifice, it projects a stable, highly uniform solid cone spray pattern characterized by extremely fine particle sizes and low droplet SMD (Sauter Mean Diameter) even at low CFM thresholds.

Key Features & Benefits

Medium & Heavy Oil Compatibility: Specially engineered to permit high-efficiency combustion with medium and heavy oils that standard pressure nozzles cannot easily process.

Clog-Free Operation: Features relatively large internal passages and a generous orifice layout, ensuring dependable, clog-free performance during low-volume fluid delivery.

Low-Pressure Efficiency: Built to achieve maximum fuel atomization while operating under strict low air pressure and low CFM requirements.

Omnidirectional Mounting: Offers total installation flexibility with the mechanical capability to maintain a perfect, consistent flow in either a horizontal or vertical position.

Adaptable Flow Configurations: Features highly versatile deployment options—it can operate via standard suction lift, adapt to a closed pressurized system using air pressure for both lifting and atomizing, or pair with a fuel metering pump when a constant level device is not permitted by the application.