What is a Flat Fan Nozzle?
A flat fan nozzle is a type of spray nozzle that produces a fan-shaped liquid jet with a flat cross section and sharp edges. Unlike conical nozzles that create circular sprays, flat fan nozzles spray liquid in the shape of a flat, wide rectangle or ellipse.
How Do Flat Fan Nozzles Work?
Flat fan nozzles work by forcing liquid through an elliptical, trapezoidal, or rectangular orifice. As the liquid exits the nozzle, it forms a flattened, expanding sheet as opposed to a round spray.
The liquid sheet then breaks up into ligaments and droplets. But the elongated “blade-like” shape of the orifice keeps the spray flattened even as it disintegrates.
Internal Design and Components
Inside most industrial flat fan nozzles you’ll find these key components:
- Orifice: The exit hole where the liquid emerges is elongated to shape the fan. The orifice geometry defines spray angle, flow rate, and distribution pattern.
- Deflector Surface: Liquid impacts an internal sloped surface before exiting, which helps flatten and spread the sheet.
- Body: Houses internal components and connects to pipe thread fittings. Typically made of brass, stainless steel, or engineering plastic.
Some lightweight flat fan nozzles use external deflection instead. A solid stream hits an angled “spoon” to flatten before exiting the nozzle.
Spray Characteristics
Compared to cone nozzles, flat fan sprays have:
- More impact force concentrated in a narrow area
- Larger droplet sizes on average
- Sharply defined spray width and edges
- Shape tailored for coating flat surfaces
Many factors determine the spray pattern dimensions and flow rate such as liquid pressure, nozzle dimensions, fluid viscosity, and spray angle.
Why Use a Flat Fan Nozzle?
thanks to their intense linear impact, high liquid flow rates, and modular spray angles, flat fan nozzles excel in these industrial applications:
Surface Cleaning
High-pressure flat fans generate a cutting liquid blade for intense scrubbing action. Different fan angles concentrate impact force for varying needs. Wide fans up to 110° cover big areas while narrow 15-60° fans drill into tough buildup.
Line-Striping and Coating
Flat fan nozzles lay down an “even coat” of paint, sealant, oil, or release agent onto flat surfaces. Adjustable flat fan tips meter flow for precision striping jobs like roads, turf, aircraft, and precision instruments.
Paper Processing
Flat fans provide the wide coverage, precision edges, big flow rates and droplet control needed for water-based applications in paper mills, printers and packaging plants. Uses range from lacquer spraying to edge-dyeing for decorative tissue and cleaning huge calender rolls.
Vehicle Washing
Tunnel wash systems rely on rows of flat fan jets to blanket vehicles with high-pressure detergent solution. The sharp fan spray edges wrap around complex curves and deliver strong impact to all surfaces. After soaping, angled flat rinse fans wash away solvents without water spotting.
Types of Flat Fan Nozzles
While all flat fans generate wide rectangular sprays, nuances in internal geometry create nozzles suited for different needs.
Standard Flat Fans
General multi-purpose flat fan nozzles have tapered spray edges and a parabolic distribution curve concentrating most liquid in the center. Standard flat fans work for everything from basic washdowns to precision surface coating.
Deflector Fans
Deflector fans make uniform square or rectangular patterns thanks to liquid impacting a precisely angled external “spoon” after exiting the nozzle. Clog-resistant deflector flats put out coarse droplets and gentler impact force over a consistent area.
Wide Angle Low Pressure
These flat fan nozzles range between 65° and 130° spray angles. The extreme spray widths concentrate less impact energy but cover more territory. Flow geometry or swirl pressure chambers keep the wide sprays coherent at low inlet pressures.
Narrow Angle High Pressure
Narrow flat fan angles between 15° and 60° really concentrate liquid impact. Tiny passageways prevent clogging while specialized chambers and deflectors create precise, high-pressure blades. These rugged narrow jets cut through tough oily buildups in industrial bays.
Fogging
Low flow fogging flat fans atomize liquid into vanishingly fine droplets measured in microns. Specialized construction prevents clogging while precise swirl chambers ensure an even rectangular fog distribution. Uses include humidification systems and theatrical effects like smoke and haze FX.
Factors That Affect Flat Fan Nozzle Performance
While simple in concept, many interrelated factors determine how a flat fan nozzle ultimately performs:
Inlet Pressure: Too little pressure causes uneven, drifting spray lines while excessive pressure yields a finely atomized round spray negating the purpose of using a flat fan nozzle.
Fluid Viscosity: Thicker fluids strain against nozzle passageways interfering with designed flow dynamics leading to abnormal spray behaviour. Restrict use of coatings, adhesives or oils to recommendations for that nozzle’s design.
Temperature: Hot/cold temperatures influence liquid viscosity throwing off calibrated nozzle performance. Consider heated spray systems for materials sensitive to thermal changes in viscosity.
Wear: External impacts and prolonged abrasion degrades precision-machined orifices and deflector surfaces changing spray distribution and impact profiles over time.
Clogs: Any unsuspended particulate contaminates can cling to orifice “lips” and deflector surfaces distorting spray patterns temporarily or permanently depending on material. Even tiny flecks warrant immediate inspection and cleaning to prevent permanent damage.
Off-Axis Alignment: Flat fan nozzles require precise orientation relative to targeted surfaces. Minor misalignments stir unpredictable results rapidly deteriorating optimal performance capabilities.
Key Specifications
Critical specifications needed to select an appropriate flat fan nozzle include:
- Flow Rate: At what volume must liquid be dispensed onto the surface? This determines orifice size along with inlet liquid pressure.
- Spray Angle: Width of spray measured from edge to edge required to cover the surface with liquid. For moving surfaces also factor in width relative to travel speed.
- Impact Force: Does the application require gentle mists or intense blast cleaning power? Impact force relies on dynamic pressure which relates to flow rate and inlet pressures.
- Droplet Size: Finer droplets ensure even coatings while larger droplets minimize drift and post better impact force. Droplet size links to pressure, orifice design and liquid properties like viscosity and surface tension.
- Distribution Pattern: The liquid distribution curve, usually parabolic, square, rectangular or tapered, signifies the spray density profile across the fan width. Center-weighted parabolic patterns concentrate impact while square profiles ensure blanket-like uniform coverage.
- Construction Material: The fluid chemistry and spray environment chemistry dictate suitable metals for the fluid body. Consider not just corrosion but also thermal expansion, abrasion resistance and potential contamination.
Matching your operational requirements to nozzle specs ensures picking the right flat fan nozzle for your specific application. Beyond requiring lower pressures and finer atomization compared to solid streams, flat fan nozzles afford customizable impact distribution, flow rates and spray coverage ideal for projecting a liquid “blade” against flat or contoured surfaces. Whether gently wetting or power washing, flat fans provide adaptable wide-area linear liquid impact from precision machined passages designed to atomize flowing liquid into elongated sheets ideally shaped for coating planar surfaces.