Misting Nozzles

A misting nozzle makes droplets small enough that they do their job before gravity pulls them to the ground. For cooling, that means evaporating into the air and carrying heat away; for humidification, suspending long enough to raise moisture; for dust, weighing particles down. The entire discipline is controlling droplet size, and droplet size is set almost entirely by orifice and pressure.

This sits at the fine end of the spray spectrum, finer than a flat fan, finer than most atomizing nozzles, and far more sensitive to water quality. The range on this page is a high-pressure line: the sub-30 µm droplets that make a dry fog only form once the line runs at 70 bar and above.

Orifice Size Sets the Droplet

Misting nozzles are sized by the orifice, not by a flow rate class. A smaller orifice at a given pressure makes a finer droplet; a larger one makes a coarser one. The volume (VMD, volume median diameter) is what decides whether the mist cools, humidifies or just wets the floor.

Too fine and the droplets evaporate before reaching the target or never wet anything useful; too coarse and you have a spray, not a mist, with dripping and poor coverage. The sweet spot depends on the duty: cooling wants enough fineness to flash off, humidification wants suspension, dust wants enough mass to drop particles without flooding.

Five orifices span the useful band of this range, 0.15 mm at the fine end, up to 0.60 mm at the coarser end, with a ceramic-insert option for abrasive water.

Pressure and Droplet Relationship

Higher pressure through the same orifice produces a finer, higher-velocity mist. The dry-fog band below 30 µm needs a serious pressure step: the reference figures on this page are quoted at 70 bar (1,000 psi class), the operating point where sub-30 µm droplets actually form. That has consequences for pump sizing and for the strainer, because a fine orifice clogs fast.

Water quality is the silent killer of misting systems. Any particulate or scale former blocks the orifice, and a blocked misting nozzle simply stops misting while everything around it keeps running. Filtration and a descaling routine are not optional.

Cooling, Humidification and Dust

Evaporative cooling relies on the droplets flashing to vapour and removing latent heat , most effective in hot, dry air where the mist disappears instead of falling.

Humidification wants the droplets to linger and raise air moisture without wetting surfaces, which favours a controlled fine spectrum and good distribution.

Dust suppression uses the mist to capture airborne particles; the droplet needs enough mass to collide with and weigh down the dust without over-wetting the material below.

Range Walkthrough: What Each Model Is For

The reference table above lists the range in one view; this section says when each model is the right answer.

MS-005 (0.15 mm): the finest standard orifice. 0.05–0.10 L/min at 70 bar producing 10–30 µm droplets, 1/8" connection in SS 303. This is the dry-fog choice for outdoor and evaporative cooling where the mist must vanish before it lands. Lowest flow per nozzle in the range, so it suits tight water budgets and duties where the droplet has to flash off fast.

MS-010 (0.25 mm): 0.09–0.15 L/min at 10–35 µm, 1/8" in SS 303 or PP. The humidification workhorse: fine enough to stay airborne and raise relative humidity, with a little more flow than the 005 for covering larger volumes without wetting surfaces. The PP body option keeps cost down on benign-water duties.

MS-020 (0.40 mm): 0.15–0.30 L/min at 15–40 µm, 1/4" in SS 316 or PP. The mid band for greenhouse and patio cooling: droplets that cool and settle gently, still fine enough not to soak the crop or the guests underneath. SS 316 for service life, PP where chemistry or budget decides.

MS-030 (0.60 mm): 0.30–0.80 L/min at 20–60 µm, 1/4" in SS 316. The coarsest standard hydraulic mist and the dust-suppression end of the range. The bigger droplets carry enough mass to collide with airborne dust and drag it down, without flooding the material below. It is also the starting point when you need more throw or more coverage per nozzle.

MS-CER (ceramic insert): 0.02–0.05 L/min at 3–20 µm, 1/4" in a ceramic/PP body. The finest droplets in the range and the only model that survives abrasive water: the fired ceramic insert resists erosion far longer than a steel bore, so the droplet band holds when the supply carries grit or scale. Spec it for dirty-water duties and anywhere the finest fog matters enough to pay for a wear part.

Application Matrix

Industry	Typical duty	Recommended class	Why
Outdoor dining & events	Patio and terrace cooling	MS-005 / MS-010	10–30 µm evaporates before it lands on people
Greenhouse & nursery	Canopy temperature control	MS-010 / MS-020	Fine enough to cool without wetting the leaf
Dust suppression	Transfer points, crushing, recycling	MS-030	20–60 µm droplets carry mass to capture dust
Data centre & server rooms	Humidity control in the cold aisle	MS-005 / MS-CER	3–20 µm fog stays airborne, no wetting risk
Textile & print	Humidification of the production hall	MS-005 / MS-010	Holds RH without wetting the web
Food display	Produce and seafood cases	MS-005 / MS-CER	Fine mist keeps product fresh, no pooling
Poultry & livestock	Evaporative cooling of housing	MS-010 / MS-020	Mist must vanish before settling on birds
Disinfection fogging	Room and surface sanitising	MS-005 / MS-010	10–30 µm stays airborne long enough to cover the volume

Three-Step Selection Framework

If the full checklist feels heavy, the decision collapses to three questions, droplet band first, then orifice, then pressure:

1. What droplet band does the duty need? Cooling wants 10–30 µm so the mist flashes off; humidification wants fine enough to stay airborne (10–35 µm); dust wants the 20–60 µm band with enough mass to capture particles. This single answer points at one end of the range or the other.
2. Which orifice delivers that band? Match the band to the model: MS-005 or MS-010 for dry fog and humidification, MS-020 for greenhouse and patio, MS-030 for dust. Abrasive or dirty water moves you to MS-CER regardless of band, because only the ceramic insert holds its orifice under erosion.
3. Then size the pressure and the pump. Run the line at the rated 70 bar, sag the pressure and every nozzle drifts coarse. Sum the flow of every nozzle at that pressure, size the pump to the total, and put filtration upstream before the first nozzle.

Reference Specifications

Orifice, flow and droplet below are quoted at 70 bar (1,000 psi class). Droplet (VMD) is the volume median diameter. Sub-30 µm dry fog requires running at or above this pressure.

How to Select a Misting Nozzle

Work through these in order and the choice usually narrows to two or three models.

• Duty first: cooling, humidification or dust each want a different droplet band.
• Orifice versus pressure: smaller orifice or higher pressure gives finer mist; pick the pair that hits the target VMD at the run pressure.
• Water quality and filtration: fine orifices demand filtration; plan strainer maintenance up front, or step to the ceramic insert.
• Distribution, not just fineness: even spacing of nozzles matters as much as the droplet size; a perfect tip on a bad layout still drips.
• Material in the environment: PP for benign water, stainless where the environment is aggressive or the temperature is high.
• Pump capacity: high-pressure misting wants 70 bar at the tip; size the pump for the total orifice area at the run pressure, not for one nozzle.

Frequently Asked Questions

Why do my misting nozzles stop misting but the pump runs? A clogged orifice, almost always scale or particulate. The fine bore blocks while the rest keep running. Filtration and descaling prevent it.

What pressure do misting nozzles need? The reference figures on this page are at 70 bar (1,000 psi class). Droplets below 30 µm, the dry fog that cooling and humidification want, only form at this kind of pressure. Lower-pressure misting exists, but it produces coarser droplets that wet instead of evaporate.

Fine or coarse mist for cooling? Fine enough to evaporate in the air and carry heat away. Too coarse drips; too fine may not wet enough to matter. The band depends on the ambient heat and humidity, start at the 10–30 µm end and coarsen only if the mist does not reach the space.

Can I use misting nozzles for dust? Yes, with a droplet sized to capture particles without flooding the material. It is a different band from cooling mist; the 20–60 µm MS-030 is where dust suppression starts.

What happens if the pressure sags? Every nozzle drifts coarse: the far end of the line turns to drizzle while the near end still mists. Size the pump to the total flow at rated pressure, check the line for pressure drop, or fit a regulator.

What water quality do misting nozzles need? Clean, filtered water. A fine orifice blocks on any particulate or scale. Fit a line filter upstream; for abrasive or hard water use the ceramic-insert MS-CER, which resists erosion and holds its droplet band.

How many nozzles do I need for a space? Count the heat load, not the area. Each litre of water that evaporates absorbs roughly 2.26 MJ of latent heat, divide the cooling load in kW by 2.26 to get litres per hour to evaporate, then divide by the per-nozzle flow at 70 bar. Space the nozzles so the mist interlaces, typically 1–1.5 m apart in a line.

Can I run the line at lower pressure to save pump cost? Only if the duty tolerates coarser droplets. Droplet size is set by orifice and pressure together; at lower pressure the same orifice makes larger droplets, and below a point the mist stops being mist. If the dry-fog band is the requirement, the pump has to hold 70 bar.