How does an Air Blast Sprayer work?

Air Blast Sprayer uses suction to convert liquids or other chemicals into a mist, spraying them evenly onto objects. It's widely used in agriculture, gardening, and other fields. Do you know how it works? Let's learn more with Shuoxin.

Airflow Atomization Based on Bernoulli's Principle

Air Blast Sprayer has an air channel and a liquid channel. The air in the air channel is compressed or accelerated by a device, such as an air pump or fan, to achieve a high flow rate. When the high-speed airflow passes through the trifurcated pipe connecting to the liquid channel, the pressure differential causes the liquid in the liquid channel, with a relatively low flow rate, to flow from the high-pressure area to the low-pressure area, where the high-speed airflow is located, according to Bernoulli's principle. Some pneumatic garden sprayers achieve air speeds of up to 15 m/s when the air pump is operating. This pressure differential forces the water in the liquid channel to flow toward the high-speed airflow, where it breaks the water into small droplets. Just like water flowing from a faucet in everyday life, it starts out as a slow column, then accelerates to form droplets. These small droplets, driven by the high-speed airflow, are ejected into a mist, achieving uniform spray coverage on plants.

High-pressure water stream breaks into droplets upon impact

Some air blast sprayers create a high-speed stream by forcing water into a capillary tube. For example, a simple household sprayer uses a push-type sprayer. Pressing the handle pushes a piston, compressing the interior of the sprayer and applying pressure to the liquid. This pressure forces the liquid into the capillary tube, which typically has an inner diameter of 1-3 mm. For example, a 2 mm inner diameter tube can increase the liquid's flow rate to over 5 m/s, creating a high-speed stream. When the high-speed water stream exits the capillary tube and encounters an obstacle, such as a baffle or special structure inside the nozzle, the stream is blocked and fragmented. This is similar to turning on a faucet and partially blocking the outlet with your finger: the water flow is blocked and dispersed into small droplets. These small droplets are ejected from the nozzle as a spray. Due to its simple structure and cost-effectiveness, it is widely used in daily cleaning and other fields.

Centrifugal Force-Driven Liquid Dispersion

Some Air Blast Sprayers feature high-speed rotating components, such as the atomizing disk, which is typically driven by a motor that can reach speeds of several thousand revolutions per minute, with a typical speed of 3,000 rpm. As the motor drives the atomizing disk at high speed, the liquid to be sprayed is delivered to the center of the atomizing disk. Due to the centrifugal force (F=mrω² (F is the centrifugal force, m is the mass of the liquid element, r is the radius of rotation, and ω is the angular velocity), the liquid element experiences an outward force in the radial direction. Driven by this centrifugal force, the liquid is flung from the edge of the atomizing disk. As the rotation continues, the liquid is continuously broken into smaller and smaller droplets, much like a spinning umbrella, where raindrops are flung along the edge of the umbrella. The small droplets thrown out spread out to form a spray. This principle is often used in processes such as spray drying in industrial production and can efficiently achieve liquid atomization processing.The following are the main components and functions of an air blast sprayer.