Misting Nozzles Explained

Misting systems are used to cool outdoor spaces in all sorts of industries and for all kinds of purposes. They are used to ensure comfort of visitors in public venues and commercial establishments, and they are also used in industrial plants and for agriculture applications. One of the most important components of a cooling system is the misting nozzle. All misting systems are comprised of a series of nozzles placed in a line.

When attached to high-pressure pumps, water is forced through nozzles, forming droplets which evaporate into mist when they reach the outdoor air. This can reduce the temperatures by 35 to 40 degrees Fahrenheit. If the misting system is in a confined indoor area, it will provide a cool mist but will also increase humidity.

Types of Misting System Nozzles

Nozzles come in two varieties: impeller and impingement. Impeller nozzles are most commonly used for residential and commercial applications. They use barrel-shaped rotors to control water flow and pressure. The water is reduced to tiny drops which burst through the openings, creating tiny droplets that form a cooling mist. Impingement nozzles produce a straighter stream of water and are typically only used for specialty applications.

Cleaning Misting System Nozzles

There are cleanable and non-cleanable impeller mister nozzles. The cleanable nozzle has an impeller that can be removed from the nozzle in order to flush the system with cleaning solution, which unplugs blocked orifices. These nozzles are also equipped with a special piece that ensures it does not drip every time it is turned off. Non-cleanable nozzles cannot be taken apart to clean, so they do not usually last as long.

Impingement Nozzles Vs. Impeller Nozzles

Impingement nozzles allow water to exit the nozzle in a straight stream through a very small orifice (typically .008″ or about 200μ or microns) and immediately collide with a solid pin, which effectively atomizes the water into tiny droplets, usually between 1μ and 15μ. Impingement nozzles tend to be very expensive; it is hard to maintain the position of the solid pin, which makes it hard to maintain their performance. They are typically used in specialty applications.

Used in the mist and fog industry for over 50 years, impeller nozzles are the most common misting nozzle. They are much less expensive and much more reliable than impingement nozzles. However, they cannot consistently produce as fine a droplet as an impingement nozzle. This is not an issue for the vast majority of applications, so impeller nozzles are widely used. A well-designed impeller nozzle will produce droplets ranging from a few microns to about 50μ, with the majority of the droplets being larger than 10μ.

Although there have been improvements to impeller misting nozzles over the last 20 years, the basic performance and function have not changed. Essentially, impeller nozzles are designed to atomize the water flow into tiny droplets. These nozzles utilize a barrel-shaped impeller, a small orifice, and a vortex-shaped interior to force the water through the nozzle in such a way that it explodes through the small opening in a circular motion, resulting in billions of tiny individual droplets.

When placed in a series along a length of tubing or onto the facing of a fan, the water is absorbed by the air for evaporative cooling. These nozzles are available in brass and stainless steel or in all stainless steel designs. They are also available with standard orifice sizes from .006″/.015mm to .020″/.5mm. Larger orifice sizes are available upon request.

Standard Mist Nozzles Vs. Cleanable Mist Nozzles

There are two basic types of impeller nozzles: cleanable and non-cleanable. The cleanable mist nozzle allows the barrel-shaped impeller to be removed from the body of the nozzle, allowing for easy removal of foreign debris and flushing with cleaning solution. In 95% of cases, a poor spraying or plugged nozzle can be dis-assembled and cleaned, returning the nozzle to its original performance capability.

Cleanable nozzles also include an anti-drip assembly inserted into the body of the nozzle. This assembly prevents misting nozzles from dripping each time the system is turned off. In some applications this is not that important, but if preventing the nozzle from dripping is important, anti-drip assembly is crucial. Anti-drip assembly can be removed from the nozzle if not required.

Standard non-cleanable nozzles are less expensive, but cannot easily be cleaned. The success rate for improving a plugged or poor spraying non-cleanable nozzle is about 50%. In most cases, the overall investment of the entire misting system justifies the extra cost of the cleanable nozzles. They usually pay for themselves within the first year.

Misting Nozzle Sizes

.006″/.15mm Nozzle (Yellow O-Ring): The smallest standard nozzle orifice available. At 1,000 psi, the mean diameter of the droplets from this size orifice are 12.2μ with droplets ranging from 1.2μ to 36.4μ and a spray diameter of approximately 45 degrees. The .006″/.15mm misting nozzle is ideal for applications requiring extremely low flow with small droplet size and minimal moisture. It is most commonly used for humidification applications. This nozzle is not designed to be used at pressures below 500 psi.

.008″/.20mm Nozzle (Red O-Ring): The next-smallest standard nozzle orifice available. At 1,000 psi, the mean diameter of the droplets from this size orifice are 12.7μ with droplets ranging from 1.4μ to 37.9μ and a spray diameter of between 60 and 65 degrees. The .008″/.20mm misting nozzle is ideal for applications requiring low flow with small droplet size and limited moisture. It is most commonly used for humidification and cooling applications. This nozzle is not designed to be used at pressures below 250 psi.

.012″/.30mm Nozzle (Black O-Ring): The medium-sized standard nozzle orifice. At 1,000 psi, the mean diameter of the droplets from this size orifice are 13.1μ with droplets ranging from 1.6μ to 39.1μ and a spray diameter of between 65 and 75 degrees. The .012″/.30mm misting nozzle is ideal for applications requiring moderate flow with small droplet size. It has a similar performance to the .008″/.20mm orifice nozzle with an increased flow rate. It is most commonly used for outdoor cooling and odor/dust control applications. This nozzle can be used with any pressures above 100 psi.

.016″/.40mm nozzle (Brown O-Ring): A larger-sized nozzle orifice. At 1,000 psi, the mean diameter of the droplets from this size orifice are 14.8μ with droplets ranging from 3.8μ to 47.9μ and a spray diameter of between 70 and 80 degrees. The .016″/.40mm misting nozzle is ideal for applications requiring increased flow rates with moderately sized droplets. It is most commonly used for special effects and outdoor dust control applications. This nozzle can be used with any pressure.

.020″/.50mm Nozzle (Green O-Ring): The largest sized standard nozzle orifice. At 1,000 psi, the mean diameter of the droplets from this size orifice are 15.2μ with droplets ranging from 9.5μ to 49.9μ and a spray diameter of between 80 and 90 degrees. The .020″/.50mm misting nozzle is ideal for applications requiring extreme flow with larger droplets where complete evaporation is not required. It is most commonly used for outdoor dust control in demolition applications. This nozzle can be used with any pressure.

Essential Differences in Misting Nozzles

Brass Nozzles

Brass is used in many different types of plumbing fixtures because it is durable, resists corrosion and will not rust. There is a slight patina that can form on brass that is similar to what is seen on copper. However, this is just a very thin surface layer of corrosion that can take years to develop, if it develops at all.

Our brass nozzles have a stainless steel insert, so there is no corrosion at all on the inside of the nozzle. We offer a range of sizes to accommodate different flow rates. Our mister nozzles also have different spray patterns from sixty to ninety degrees to provide the right coverage needed.

Cleanable Nozzles

In addition to the standard mister nozzles, we also offer cleanable nozzles. These are available in brass or stainless steel. They have an anti-drip adapter included and provide everything needed for installation.

Both the standard impeller types of nozzles as well as the cleanable nozzles in stainless steel or brass are available in custom sizes. Since not all systems are the same and our nozzles are used with other misting systems, we also offer extensions, swivel fittings, and multi-thread adapters to make upgrading easy.

At Fogco, we pay attention to each component of our mister systems. This means that we design the pumps, the tubing, and the mister nozzles to integrate fully with our systems. They can also be used with your existing system to create a fine, even mist for cooling and humidification.

We have many different nozzle options to provide the right types of mist for industrial, commercial, and residential misting systems. We only use brass or stainless steel in our nozzles which allows for durability, effective droplet size production and low maintenance requirements.

Fogco can answer any questions you may have about the nozzles best suited for your residential or commercial misting system. With more than 25 years of experience in the industry, we can find the misting solution that’s right for you. Contact us today to learn more.