Table of Contents
The Cost of the Wrong Spray Nozzle
Picking the wrong nozzle type costs money before the first part is coated. The pattern is wrong, so the coverage is wrong. A flat fan at 1.5 m standoff with a 40° angle wets a band about 1.09 m wide. The formula is width = 2 × 1.5 × tan(20°).
A full cone at the same distance wets a filled circle of the same diameter. Swap the two and you miss the edges of the part, or you flood liquid into the gaps and rework the batch.
The numbers behind the miss are simple. Flow follows the square root of pressure: Q = K√P. Double the pressure and flow rises 41%, not 100%.
Coverage follows geometry: width = 2d·tan(θ/2). Move the nozzle 20% closer and the wetted band shrinks 20%, even though the nozzle never changed. Both errors show up on coating lines, wash stations and cooling banks every week. The rework bill usually outweighs the nozzle price by orders of magnitude.
The fix is not a bigger pump. The fix is the right nozzle type for the shape you must cover. The droplet size your process needs matters just as much. So does the fluid you are spraying.
This guide covers the six main types of spray nozzles: flat fan, full cone, hollow cone, solid stream, spiral and air atomizing. Each section gives the principle, the typical numbers and the applications. A comparison table at the end settles the choice.
What a Nozzle Type Actually Means
A nozzle type is a fixed combination of spray pattern, droplet class and pressure behaviour. The internal geometry decides the pattern. A slit orifice makes a band, a swirl chamber makes a cone, and a round hole with no swirl makes a stream.
No change of fluid and no change of pressure can alter that family. The deeper geometry is covered in our guide to spray patterns.
Every type obeys the same two laws. Flow: Q = K√P, where K is the nozzle constant in L/min at 1 bar. Coverage: width = 2d·tan(θ/2) for a band, and D = 2d·tan(θ/2) for a cone footprint. Droplet size is set by the type, the pressure and the orifice size.
Droplets under 100 µm are classed as fine. The band from 100 to 250 µm is medium, and 250 to 500 µm is coarse. Anything over 500 µm counts as very coarse.
Six families cover almost all industrial duty. Cone spray nozzles alone split into two families with opposite behaviour: full cone and hollow cone. The quick map below, then a full section on each type.
| Type | Pattern | Droplet class | Typical pressure |
|---|---|---|---|
| Flat fan | Band | 100–600 µm | 1–70 bar |
| Full cone | Filled circle | 300–1000 µm | 0.5–70 bar |
| Hollow cone | Ring | 50–500 µm | 1–100 bar |
| Solid stream | Point jet | Coherent stream | 20–200 bar |
| Spiral | Wide cone | 500–2000 µm | 0.7–30 bar |
| Air atomizing | Mist cone or fan | 10–100 µm | Liquid 0.3–7 bar, air 1.5–7 bar |
Flat Fan Spray Nozzle
A slit orifice or a deflector plate spreads liquid into a thin sheet. The sheet lands as a band, and the band is what most production lines need. Two edge profiles exist. An even edge distributes liquid uniformly across the band. A tapered edge fades out at the edges, which suits overlapping sprays where bands must blend.
The angle runs from 15° to 110°, with 40° to 80° covering most duties. The wetted width at distance d is width = 2d·tan(θ/2). A 60° fan at 0.5 m standoff wets 0.58 m; at 1.0 m it wets 1.15 m. For uniform film on a moving web, plan 20 to 30% overlap between adjacent fans, and hold the nozzles at a fixed standoff.
| Parameter | Typical range |
|---|---|
| Spray angle | 15° to 110°; most common 40° to 80° |
| Operating pressure | 1 to 70 bar |
| Droplet size | 100 to 600 µm |
| Flow law | Q = K√P, K per catalogue |
| Coverage | width = 2d·tan(θ/2) |
A flat fan spray nozzle earns its place wherever a plane moves past a fixed line. Typical jobs: coating and painting, parts washing and rinsing, conveyor cleaning, membrane cleaning and lubrication. The droplet range keeps the film even without fogging the area. If your duty is a band, a plane or a moving surface, start here and check the flat fan range.
Full Cone Spray Nozzle
Liquid passes a vane or a swirl chamber and exits as a solid cone. The footprint is a filled circle with no dry centre. The full cone nozzle spray pattern spreads liquid across the whole disc, which is why it is the default for anything you must surround.
The angle runs from 30° to 120°, with 50° to 90° typical. The footprint at distance d is a circle of diameter D = 2d·tan(θ/2). A 90° cone at 0.5 m covers a 1.0 m circle. Droplets are coarser than a hollow cone at the same pressure, typically 300 to 1000 µm, so the spray resists wind and drift better. Good swirl designs hold the distribution across the disc within a few percent of the mean.
| Parameter | Typical range |
|---|---|
| Spray angle | 30° to 120°; most common 50° to 90° |
| Operating pressure | 0.5 to 70 bar |
| Droplet size | 300 to 1000 µm |
| Free passage | Large; suits dirty fluids |
| Coverage | D = 2d·tan(θ/2), filled circle |
Use a full cone spray nozzle for volumes. Typical jobs: tank and vessel washing, quenching, dust suppression over stockpiles, fire deluge, gas cooling and chemical dosing. The free passage stays large relative to flow, so full cones accept fluids that would block a fine orifice. If the target is a tank interior, a round opening or a pile, a full cone is the natural first answer.
Hollow Cone Spray Nozzle
A tangential entry swirls the liquid inside the body, and the liquid exits as a thin ring. The ring breaks into droplets, and the centre stays empty. The same pressure produces finer droplets from a hollow cone than from a full cone, because the liquid sheet is thinner. Typical values run 50 to 500 µm.
The angle runs from 30° to 120°, with 60° to 90° most common. A 90° hollow cone at 0.5 m wets a ring of about 1.0 m outer diameter. The sheet thins as it leaves the orifice, and a thinner sheet breaks into smaller drops. That mechanism is why the droplet class sits below the full cone at the same pressure.
The empty centre is the feature. A ring wets both edges of a moving sheet without soaking the middle, which is exactly what strip cooling needs.
| Parameter | Typical range |
|---|---|
| Spray angle | 30° to 120°; most common 60° to 90° |
| Operating pressure | 1 to 100 bar |
| Droplet size | 50 to 500 µm; finer than full cone at same pressure |
| Pattern | Ring with empty centre |
| Coverage | D = 2d·tan(θ/2), outer diameter only |
A hollow cone spray nozzle fits heat-transfer and atomizing duties. Typical jobs: edge cooling of strip, gas scrubbing, evaporative cooling, oil burner atomizing and spray drying. The empty centre is also the failure mode. If you needed a filled circle, a hollow cone leaves a dry spot in the middle, so check the footprint before you buy.
Solid Stream Nozzle
A round orifice with no swirl produces a coherent jet. The spray angle is effectively 0° to 15°, and the stream holds together for metres instead of opening into a cone. There is no atomization, because atomization is not wanted. The energy stays in one line.
Cleaning duty typically runs 20 to 200 bar. The impact at the target rises with both flow and pressure, and a smaller stream concentrates the energy on a smaller spot. A clean round orifice holds a coherent jet for several metres before turbulence breaks it up. The stream reaches into pipes, tanks and blind bores that no cone can enter.
| Parameter | Typical range |
|---|---|
| Spray angle | 0° to 15° effective |
| Operating pressure | 20 to 200 bar for cleaning duty |
| Droplet size | Coherent stream, no atomization |
| Reach | Jet holds together for metres |
| Coverage | Point |
A solid stream nozzle is the tool for a point, not an area. Typical jobs: pipe interior washing, tank bottom flushing, high-pressure parts washing and single-point cooling. If the target is an interior you must reach, a solid stream gets there. If the target is a surface you must wet, pick a flat fan or a cone instead.
Spiral Spray Nozzle
Liquid flows through spiral grooves cut into a one-piece cone and exits as a spiral sheet. The sheet opens into a wide cone, either full or hollow depending on the body. The spiral gives the widest angles of any type, 60° to 170°, and the largest free passage relative to flow.
Because the passage is open and short, solids pass through instead of blocking. A spiral spray nozzle handles dirty water, slurries and recycle streams that would clog a swirl chamber. The trade-off is droplet size: 500 to 2000 µm is coarse, so spiral sprays are for wetting, not atomizing.
| Parameter | Typical range |
|---|---|
| Spray angle | 60° to 170° |
| Operating pressure | 0.7 to 30 bar |
| Droplet size | 500 to 2000 µm, coarse |
| Free passage | Largest of any type |
| Coverage | Full cone or hollow cone footprint |
The wide angle makes spirals the standard for dust suppression over large areas, flue gas desulfurization, scrubbers, gas cooling and fire deluge. A 120° spiral at 2 m covers a footprint over 6.9 m wide, which is why one nozzle replaces a bank of narrow cones. Dirty fluid plus wide coverage points to the spiral range.
Air Atomizing Nozzle and Mist Spray Nozzle
Compressed air shatters the liquid into fine droplets. Liquid pressure stays low, 0.3 to 7 bar, while air runs at 1.5 to 7 bar. Internal mix blends the fluids inside the body; external mix blends them outside. Either way the droplets land at 10 to 100 µm, far finer than any hydraulic nozzle at the same liquid pressure.
A mist spray nozzle is any nozzle that reliably makes droplets under 100 µm. An air atomizing nozzle does it at low liquid pressure. A hydraulic fog nozzle does it without air, but needs 70 to 140 bar to reach the same fineness. If your line has neither a compressor nor a high-pressure pump, you cannot make a true mist.
| Parameter | Typical range |
|---|---|
| Droplet size | 10 to 100 µm |
| Liquid pressure | 0.3 to 7 bar |
| Air pressure | 1.5 to 7 bar |
| Air-to-liquid ratio | 1:1 to 10:1 by mass |
| Pattern | Cone or fan of mist |
The cost is the air. Compressed air typically consumes 10 to 30% of a plant’s electricity, so mist costs more than a coarse hydraulic spray. Use an air atomizing nozzle where fineness pays: humidification, evaporative cooling, coating of complex shapes, lubrication, disinfection and dust binding.
Droplet class decides whether the spray dries in the air or on the part. A fine mist evaporates in seconds; a coarse spray stays wet for minutes. Our air atomizing range and misting range cover both routes to a fine spray.
Six Types Side by Side
The table below puts the six types on one page. Coverage tells you what shape each type wets. Droplet size tells you how fast the spray dries and how far it drifts. Flow and pressure tell you what the pump or compressor must deliver. Use and cost settle the economics.
| Type | Coverage | Droplet size | Flow and pressure | Typical use | Cost |
|---|---|---|---|---|---|
| Flat fan | Band, 15°–110° | 100–600 µm | Q = K√P, 1–70 bar | Coating, rinsing, cleaning | Low to medium |
| Full cone | Filled circle, 30°–120° | 300–1000 µm | Q = K√P, 0.5–70 bar | Tank washing, quenching, dust control | Low |
| Hollow cone | Ring, 30°–120° | 50–500 µm | Q = K√P, 1–100 bar | Edge cooling, scrubbing, atomizing | Low to medium |
| Solid stream | Point, 0°–15° | Coherent stream | Q = K√P, 20–200 bar | Pipe washing, high-pressure cleaning | Low |
| Spiral | Wide cone, 60°–170° | 500–2000 µm | Q = K√P, 0.7–30 bar | Dust suppression, scrubbers, gas cooling | Low to medium |
| Air atomizing | Mist cone or fan | 10–100 µm | Liquid 0.3–7 bar, air 1.5–7 bar | Humidification, coating, cooling | Highest, air cost |
Read the table in order. First the pattern must fit the surface. Then the droplet class must fit the process. Then the flow and pressure must fit the supply. Only after those three match does cost separate the candidates.
The droplet column is the one most often skipped. Fine droplets evaporate fast, drift far and coat evenly. Coarse droplets fall fast, wet a small footprint and resist wind. If the process needs evaporation in the air, go fine. If it needs liquid on a surface, coarse is cheaper.
How to Choose the Type: Three Steps
Step 1: match the type to the shape you must cover. A moving band or plane takes a flat fan. A volume you must surround takes a full cone. A ring, an edge or fine droplets take a hollow cone.
A point or an interior takes a solid stream. Dirty fluid over a wide area takes a spiral. A true mist under 100 µm takes air atomizing, or a hydraulic fog nozzle at 70 to 140 bar. The full decision process lives in our 7-step nozzle selection guide.
Step 2: match the material to the fluid. Fluid chemistry rules out materials fast. A pH below 6 or above 9 rules out brass, and chlorides rule out brass and 304 stainless.
Abrasives call for hardened steel or tungsten carbide tips. Strong acids call for PTFE or PVDF bodies. Check the material temperature limit against the process temperature as well.
Step 3: match the size to the flow and pressure. Measure the pressure at the nozzle, not at the pump discharge. The pressure drop through pipes and filters is real, often 10 to 30% of pump pressure. Then compute K = Q ÷ √P, where Q is the target flow in L/min and P is the pressure in bar.
A duty of 12 L/min at 3 bar gives K = 12 ÷ 1.73 = 6.9. You then order the nozzle closest to K 6.9 in the catalogue.
Common Mis-Selections and Their Fix
| Mis-selection | Result | Fix |
|---|---|---|
| Full cone on a moving web | Uneven film, wet edges | Flat fan with 20–30% overlap |
| Hollow cone where a filled circle is needed | Dry centre in the pattern | Full cone |
| Solid stream to wash a wide part | Streaks, slow cycle | Flat fan or full cone |
| Spiral where fine atomization is needed | Droplets far too coarse | Hollow cone or air atomizing |
| Air atomizing where a hydraulic spray suffices | Compressed air cost, 10–30% of plant electricity | Flat fan or full cone |
| Angle picked without checking standoff | Coverage off by half | Recompute width = 2d·tan(θ/2) |
| Brass in a chloride line | Corrosion, blocked orifice, drift | 316 stainless or higher |
Every row on this table is a nozzle swap, not a pump upgrade. Most mis-selections are caught by writing down the shape to cover and the droplet class you need before opening a catalogue.
FAQ
What are the main types of spray nozzles? Six families cover industrial duty: flat fan, full cone, hollow cone, solid stream, spiral and air atomizing. Each has a fixed pattern set by internal geometry.
Flat fan or full cone: which do I need? The shape decides. A band or a moving plane takes a flat fan. A volume, a tank interior or a round area takes a full cone.
When does the empty centre of a hollow cone matter? When you need edges wetted without the middle soaked, the empty centre is a feature. When you need a filled circle, it is a failure. Check the footprint before ordering.
What droplet size does a mist spray nozzle make? Under 100 µm. Air atomizing reaches that at liquid pressure of 0.3 to 7 bar. Hydraulic fog needs 70 to 140 bar to reach the same fineness without air.
How do I calculate nozzle flow? Use Q = K√P. Double the pressure and flow rises 41%. The K factor is published per nozzle size and stays constant across the operating range.
Can pressure change the pattern? No. Pressure changes flow, droplet size and, slightly, the angle. The pattern family is fixed by the orifice geometry. If the pattern is wrong, change the nozzle, not the pump.
Can one nozzle serve two patterns? No. Adjustable nozzles vary the angle or the flow, not the pattern family. A full cone stays a full cone at every setting, so buy the type the duty needs.
Final Checklist Before You Order
- Pattern matches the shape to cover: band, circle, ring, point or mist.
- Droplet class fits the process: under 100 µm for mist duty, coarse is fine for washing.
- K factor computed from the pressure at the nozzle, not the pump.
- Material compatible with pH, chlorides, abrasives and temperature.
- Thread matches your line: BSP, NPT or metric, never forced.
- Free passage larger than the largest solid particle in the fluid.
- Angle checked against standoff with width = 2d·tan(θ/2).
- Spare nozzle verified at the real operating pressure before series order.
Run the checklist once and the shortlist drops to two or three candidates. That is the entire point of classifying nozzles by type instead of browsing 5,000 catalogue lines.
Send Us the Duty, Get the Type
Describe the duty and we will name the type. Send the flow in L/min and the pressure at the nozzle. Add the fluid chemistry, the shape to cover and the droplet size you need. Send the numbers to our contact page and you get a type, a material and a size recommendation, not a catalogue dump.
Most duties resolve to a flat fan, a full cone or a spiral. We will tell you which one, with the K factor and the thread, before you order a single piece.
Related reading: how spiral nozzle selection handles open passage and grit, flat fan versus full cone when coverage decides, and the nozzle spray angle guide for the angle-standoff arithmetic behind every pattern here.
Next Step
Send the Duty. Get Sized Nozzles Back.
Send your flow, pressure, fluid and target coverage. We come back with nozzle options and figures, not a catalogue number.
Written by
Ray ChanIndustrial spray nozzle specialist. I size tank cleaning, atomizing, flat-fan and spiral nozzles against real duty conditions, flow, pressure, fluid and target, rather than catalogue numbers. Every guide here comes from actual sizing work.