Spray Nozzles
Hollow Cone
The hollow cone spray pattern is essentially a circular ring of liquid.
This pattern is generally formed by use of an inlet tangential to a whirl
chamber, or by an internal grooved vane immediately upstream from the
orifice. The whirling liquid results in a hollow cone configuration as it
leaves the orifice.
Full Cone
A full cone spray pattern is round, square, or oval in coverage, and
completely filled with spray drops. This spray pattern is normally formed
by using an internal vane, which imparts controlled turbulence to the
liquid prior to the orifice. Full cone coverage can also be accomplished
with smaller drop size by use of a header arrangement of atomizing or fine
spray nozzles.
Solid Stream
A solid stream spray pattern is basically a uniform stream of liquid
emitted through a drilled hole. However, modern solid stream nozzles have
been refined by the use of proper inlet chamber proportions and contours
ahead of the orifice and/or by addition of internal flow stabilizing
vanes. These nozzles provide prolonged solid stream integrity and delay
the start of breakup and drop formation after leaving the nozzle orifice.
Flat Spray
A flat spray pattern distributes the liquid as a flat- or sheet-type
spray. The flat spray pattern is formed by use of an elliptical orifice,
or by a round orifice tangential to a deflector surface. In the elliptical
orifice design, the axis of the spray pattern is a continuation of the
axis of the inlet pipe connection. In the deflector design, the deflection
surface diverts the spray pattern away from the axis of the inlet pipe
connection. Straight-through elliptical orifice spray nozzles normally
produce flat spray patterns with tapering edges. This characteristic is
useful in establishing overlapping patterns between adjacent sprays on a
multiple-nozzle header. The resulting distribution across the entire
sprayed surface can therefore be uniform. Flat spray nozzles with
non-tapered or "even" edges are usually used in cleaning
applications that require uniform impact across the entire pattern width
without overlapping the sprays.
Fine Spray
These low-capacity nozzles produce a hollow cone spray pattern. Since
the spray drops are very small, the spray pattern is affected by air
friction and currents, and is not maintained for long distances. Several
feet from the nozzle, depending on spraying pressure and nozzle capacity,
the fine spray pattern disappears as the drops become suspended in air.
Nozzles used for spray-drying applications at pressures of 1,000 psi (70
bar) or greater perform similarly.
Air Atomizing
Air atomizing nozzles provide the finest degree of atomization for a
given capacity and pressure. There is a choice of patterns: round,
wide-angle round, 360° round, or flat. The spray pattern
remains only as long as the velocity of the atomizing air is maintained.
The spray drops may evaporate completely, depending on their size,
exposure time, the relative humidity, and other ambient conditions.
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