What Is a Misting Nozzle?
Misting nozzles are nozzles used in misting equipment.
Misting nozzles are used to spray and disperse liquids such as water in the form of a fine mist. The point where the liquid comes out as a mist is called the atomizing hole, which can spray liquids under high pressure. To prevent abrasion, materials such as highly resistant stainless steel are used.
There are two main types of misting nozzle spraying methods: one fluid and two fluid. The one-fluid uses only high water pressure to produce mist, while the two-fluid uses low pressure of air to crush water to create mist. Misting nozzles have different characteristics depending on the size of the nozzle bore and the pressure at which the liquid is pushed out of the pump. To realize high effectiveness, it is necessary to use the misting nozzle that best suits the purpose and application.
Usage of Misting Nozzles
Misting nozzles spray water in the form of mist to maintain a certain level of humidity, and through the mechanism of heat of vaporization, in which water and other liquids evaporate, they remove heat from the surroundings. For this reason, they are often used for cooling purposes such as reducing temperature rise.
In addition, they can also be used for watering livestock and vegetable gardens, as well as for sterilization and cleaning by spraying disinfectants and chemicals.
In the entertainment industry, they are also used to create various forms of mist, depending on the shape of the nozzle.
Principle of Misting Nozzles
Misting nozzles can change the size of the mist particles by the size of the nozzle bore and the amount of pressure applied by the pump. To make the mist finer, the diameter of the nozzle is reduced and the pressure of the pump is increased.
The amount of liquid discharged from the misting nozzle becomes smaller when the bore size is smaller, but larger when the pump pressure is larger, so the balance can be adjusted to suit the application. And the finer the mist particles, the easier it is to evaporate.
Types of Misting Nozzles
There is a wide variety of misting nozzles depending on the intended use, such as for fluidized bed dryers, continuous casting machines, and flue gas desulfurization equipment.
1. For Fluidized Bed Dryers
For fluidized bed dryers, the particle size when spraying can be adjusted. It can be powdered to suit the raw material and sprayed on food, medicine, etc.
2. For Continuous Casting Machines
Continuous casting machines are used in the steel industry. During the solidification process of molten steel using a continuous casting machine, the inside of the cast piece can be cooled by spraying water to solidify it.
3. For Flue Gas Desulfurization Equipment
For flue gas desulfurization equipment, a fluid mixed with powdered lime and water is sprayed by a spray nozzle in the process of removing sulfur dioxide from the flue gas of flue gas desulfurization equipment using the lime plaster method.
How to Select a Misting Nozzles
One-fluid misting nozzles can provide a cooling environment with low environmental impact. Two-fluid misting nozzles have better vaporization efficiency than one-fluid nozzles and produce a fine mist. Both one- and two-fluid misting nozzles are available in a wide variety of types.
Misting nozzles with various atomizing hole aperture sizes can be selected according to the purpose of misting and the location where the nozzle is installed. Misting nozzles made of brass or stainless steel prevent the atomizing holes from widening due to wear.
Misting nozzles that can be disassembled for internal cleaning when clogged, as well as misting nozzles that can prevent water droplets from falling from the nozzle when the misting equipment is stopped are also available.
Misting Nozzles Structure
Misting nozzles are classified into two types of structures: internal mixing type and external mixing type.
1. Internal Mixing Type
Misting nozzles of the internal mixing type allow water and air to flow into the nozzle separately and mix them inside the nozzle to create a mist. However, even if they flow into the space inside the nozzle, they cannot atomize and the spray is not stable. It is necessary to design the nozzle to prevent backflow from the air side to the waterside and to devise the structure of the internal space for mixing.
2. External Mixing Type
Like the internal mixing type, the external mixing type also allows water and air to flow in separately, but instead of mixing them internally, they are mixed at the outlet of the nozzle tip. The external mixing type does not pressurize water but can be self-primed by air. No pressurized tank or pump is needed, thus reducing costs. Since it is affected by the difference in water head, care must be taken in adjusting the flow rate. Self-priming type requires air volume to suck up water and is not suitable for nozzles with large water volume, but suitable for nozzles with small flow rates.