Air Knife Structure and Design
The air knife is composed of three main parts: an air inlet, a high-pressure chamber, and a narrow elongated nozzle. When compressed air enters the high-pressure chamber from the air inlet, it is ejected through a slit-shaped nozzle, forming a uniform high-speed airflow sheet.
The physical basis of this process is the Coanda Effect, where high-speed airflow adheres to and flows along adjacent solid surfaces. In typical designs, the chamber compression ratio for high-pressure airflow reaches forty to one, meaning one unit of compressed air generates forty times the volume of high-speed airflow.
This design minimizes airflow velocity loss while maximizing pressure, forming an airflow sheet with strong impact force but minimal shear force. The gap at the air knife outlet is precisely controlled to ensure uniformity and stability of the airflow across the full working width.
Material Selection
Material selection directly affects air knife performance and service life. Industrial air knives typically use aluminum alloy or stainless steel. Aluminum alloy versions undergo anti-oxidation treatment and withstand most industrial environments. For high-temperature or corrosive applications, stainless steel provides superior durability. The precision-engineered nozzle slot is the most critical component, with gap tolerance directly affecting airflow uniformity.
Key Applications
Air knife cutting uses compressed air through a narrow nozzle to form an airstream with strong impact force, capable of cutting materials such as acrylic, aluminum alloy, and high-density fiberboard with smooth and burr-free results.
In semiconductor manufacturing, air knives maintain the extremely high cleanliness requirements of chip production. In automobile manufacturing, they clean residues after body painting. In food and beverage packaging, they rapidly dry surface moisture. The non-contact nature of air knife operation is ideal for applications demanding high cleanliness standards.
Performance Factors
Optimal performance requires clean, dry compressed air at stable pressure. Regular inspection of the nozzle slot for wear or blockage is essential. Modern systems incorporate variable frequency controllers for flexible power output adjustment, and intelligent control systems enhance operational convenience and efficiency.
