(1) Pneumatic atomization is a method of atomizing liquid medicine into droplets by using high-speed airflow. The high-speed airflow first stretches the liquid medicine into liquid filaments, which are broken into liquid droplets, and the high-speed airflow blows the liquid droplets into saccular bubbles and breaks them into fog droplets. There are two kinds of pneumatic atomization: thermal atomization and normal temperature atomization. Thermal atomization is a kind of high temperature and high pressure airflow produced by internal combustion engines such as automobiles and tractors. Room temperature atomization uses a non-hot airflow.
(2) The hydraulic atomization method exerts pressure on the liquid medicine, forcing it to be ejected through the hydraulic nozzle, and then colliding with the static air outside to disperse into droplets. Hydraulic spray head is the most widely used spray head at home and abroad. It is used in compression sprayers, single-tube sprayers and tractor-drawn or suspended sprayers in China, which belongs to hydraulic atomization method. This atomization method is characterized by large spray quantity, thick and uneven droplets, and the thickness of droplets is greatly affected by pressure, so maintaining sufficient pressure is the key condition to obtain good spray quality. ?
(3) The centrifugal atomization method uses the centrifugal force generated by the high-speed rotation of the nozzle to atomize the liquid medicine into fine droplets.
There are two kinds of nozzles that produce centrifugal force:
① Rotary atomizer. Dongfanghong-18 and similar models are also equipped with rotary atomizer, which can be installed at the nozzle for ultra-low volume spraying. The turntable is a disk with a certain number of half-angle serrations on its circumferential edge. When the disk rotates rapidly, the liquid medicine moves to the edge of the disk, and finally leaves the disk under the action of centrifugal force, and is thrown into the surrounding air to form droplets. This phenomenon is like spinning an umbrella quickly in the rain, and the rain on the umbrella is thrown from the edge of the umbrella to form water droplets.
② Rotating cage atomizer. Mainly installed on aircraft, used for low-volume and ultra-low-volume spraying. It uses the wind speed when the plane flies to produce high-speed rotation, and the liquid medicine is broken and thrown out under the centrifugal force of the rotating cage, and atomized into droplets. The fineness of droplets formed by centrifugal atomization depends on the rotating speed of turntable or cage, the surface tension and viscosity of liquid medicine and the acceleration of liquid medicine droplets. The higher the rotating speed, the slower the liquid medicine drops and the finer the atomization. Both the rotating speed and the droplet acceleration can be controlled artificially, so the atomization fineness can be controlled artificially.
(4) Electrostatic atomization is a method of atomizing liquid medicine by electrostatic force. There are two kinds of electrostatic atomizers: those with and without disks. The atomization principle of rotary electrostatic atomizer is the same as that of rotary centrifugal atomizer. Diskless electrostatic atomizer relies on electrostatic high-voltage electric field to develop liquid medicine into liquid silk, and finally the liquid silk breaks to form liquid droplets.
The above is a common method of atomizing liquid medicine into droplets when spraying.