The role of the disinfection nozzle is to atomize the liquid, forming a small size liquid mist.

In order to comprehensively evaluate the atomizing performance of the disinfecting nozzle, several indexes were put forward, including atomizing fineness, atomization uniformity and atomization cone Angle.
 
The droplet size after atomizing reflects the particle fineness of atomization and is an important index to evaluate the atomization quality.
 
The Droplet size and droplet size spectral distribution are important indexes to evaluate the performance of disinfecting atomizing nozzles.
 
The fog field formed by disinfection nozzle spray is composed of droplet swarm particles of different sizes. The accuracy of droplet size measurement is closely related to the method of droplet sampling and the accuracy of measuring instrument.

Atomizing fineness

The droplet size after atomizing reflects the atomized particle fineness and is an important index to evaluate the atomization quality.
 
In general, the finer the fog droplet, the easier it is to heat, evaporate, and burn.
Due to the uneven size of droplet diameter, sometimes the maximum and minimum values differ by 50-100 times, Atomized particles about 15-60 microns in diameter，so the concept of average droplet size can only be used to represent the atomization fineness.

Many methods have been proposed to calculate the mean diameter. The most commonly used ones are Median Mass size(MMD) and Sauter Mean size(SMD or D32).

Representation of spray droplet size

Droplet size refers to the size of each spray droplet that constitutes the spray shape of the disinfection nozzle.
In a given spray, all spray droplets are not of normal size.
 
There are three methods to describe droplet size in spray: volume median sizeDV0.5 (VMD), mass median size(MMD), Shaw mean size(SMD) and quantity median size(NMD).
 

VMD/MMD	A method of representing droplet size by the volume of the spray liquid.When measured according to volume, the droplet size of the median volume size is a numerical value, that is, in the total volume of the spray liquid, 50% is composed of droplet whose size is larger than the median value, and 50% is composed of droplet whose size is smaller than the value.
NMD	a method to indicate droplet size by the number of droplet in spray.That means, in terms of numbers, 50% of the droplets are smaller than the median diameter, and 50% of the droplets are larger than the median diameter.
SMD	A method of representing spray fineness in terms of the surface area produced by the spray.Salt mean size is the size of a droplet whose ratio of volume to surface area is equal to the ratio of total volume to total surface area of all droplet.

 
 

The concept of droplet size for disinfection

The particle size of heavy rain is 5000-2000μm, and the fog that can be seen from a distance is about 0.01-0.001μm. The smoke of the cigarette is about 0.01 μm.
 

5000~2000	Heavy rain
2000~1000	Strong rain
1000~500	Ordinary rain
500~100	Light rain
100~50	Fog rain
50~10	Wet rain
10~2.8	Dry fog	Floats in the air and will not get wet even when it touches solids.
1.0~0.01	Fog
0.01~0.001	The smoke of cigarette
0.001 the following	Molecular size