Can compressed air blow products directly?
Compressed air should not be used directly for purging products for the following reasons:
1. Risk of impurity pollution
During the process of compressing air, impurities such as pipeline rust, lubricating oil particles, and water vapor will be mixed into the air compressor. Taking particles with a diameter of 0.1 microns as an example, each cubic meter of compressed air may contain millions of such particles. When these impurity-containing air currents directly contact products, they may cause quality problems such as sticking of precision parts, surface scratches of optical elements, and contamination of food and drug packaging.
2. Hidden dangers of physical damage
The compressed air pressure is usually in the range of 0.6-1.0MPa, which is equivalent to a force of 6-10 kilograms per square centimeter. When the nozzle is less than 20 cm away from the product surface, the impact force of the air flow can reach 50- 80N, which is enough to form tiny scratches 0.01-0.05mm deep on the metal surface. For soft materials such as plastic and rubber, permanent deformation may occur.
3. Safe use specifications
If compressed air is needed for purging, the following operating specifications should be followed:
- purification treatment: Install a three-stage filtration system at the outlet of the air compressor. The first stage filters particles above 5 microns, the second stage filters 1 micron particles, and the third stage filters 0.01 micron particles. At the same time, a cold dryer is configured to control the pressure dew point at 2-7℃ to ensure that the oil content of the outlet air is ≤0.01mg/m³.
- pressure control: Stabilize the working pressure at 0.2-0.3MPa through a pressure reducing valve, and install a pressure gauge at the nozzle for real-time monitoring.
- protective measures: Operators need to wear goggles, keep a distance of more than 30 cm between the nozzle and the product surface, and control the purging angle within 45° to prevent the airflow from directly impacting the edge of the product.
- static elimination: Add an ionic wind bar to the air pipeline to neutralize the static electricity generated in the air flow and prevent static electricity from adhering to particles or penetrating electronic components.
4. Alternative solutions
For scenarios requiring high precision, the following alternatives are recommended:
- Clean gas purge: Use inert gases such as nitrogen, precise filtration of 0.01 microns and then purge. It is suitable for semiconductor wafers, biomedical containers and other scenarios.
- contact cleaning: Wipe with a dust-free cloth dipped in isopropyl alcohol, and use a vacuum cleaning system to achieve Class 100 cleanliness.
- directional airflow control: Design a special purging tool to control the air flow speed within 15m/s through the air guide. It is combined with HEPA filter unit to be suitable for optical lenses, precision molds and other scenes.
As a commonly used power source in the industry, compressed air requires strict evaluation of product characteristics and process requirements for direct purging applications. By implementing measures such as purification treatment, pressure control, and electrostatic protection, safe use can be achieved under certain conditions. However, for scenarios with high precision and high cleanliness requirements, it is recommended to give priority to alternative cleaning solutions.
