We all know that dust and other contaminants can compromise the quality of electronic components and thin-film products. To improve product yield, clean booths have been introduced. However, even in a Class 100 cleanroom, the primary and secondary filters in the ventilation system cannot completely remove particulates; over time, these particles accumulate and can adversely affect high‑precision products. Therefore, it is necessary to install clean booths on the production lines or equipment handling such products.

A clean booth recirculates air from the cleanroom, further filtering it through HEPA filters before delivering it into the production area. Depending on the cleanliness requirements of the workshop, clean booths are classified into three grades—10,000, 1,000, and 100—ranging from low to high. With a sealed top and four sides, and an open bottom clearance of approximately 10 cm, the FFUs mounted at the ceiling continuously supply downward airflow, maintaining positive pressure inside the booth. This prevents external dust from entering and, to some extent, reduces airborne particulates generated by personnel frequently entering and exiting the booth.

The ceiling of a clean booth is typically quite high, and the FFU is positioned much closer to the production equipment than the distance between the ceiling’s air supply outlet and the equipment. This results in a noticeable airflow that effectively removes particulates. As a result, the cleanliness of the localized production area is significantly enhanced, naturally leading to improved product yield.

Additionally, if you wish to enhance the cleanliness level of an existing clean booth, the only option is to add professionally manufactured FFUs. Should you need to relocate or install additional equipment inside the clean booth, simply reposition the booth or the FFUs—providing convenience and flexibility.

A clean booth is a simple, cost-effective purification device that delivers high cleanliness levels and offers easy mobility. The FFU is mounted on a frame assembled from aluminum profiles or square ducts. Its top is sealed with a blanking plate to ensure an airtight seal, while the perimeter is enclosed by antistatic curtains or antistatic acrylic panels. Positive pressure at the booth’s base facilitates natural exhaust ventilation, enabling the internal environment to achieve a cleanliness level ranging from Class 10 to Class 100,000.

The airflow in a clean booth is a critical factor affecting the performance of a cleanroom. Typical airflow velocities range from 0.25 to 0.5 m/s, which fall within the “breeze” regime and are easily disturbed by human activity and equipment movements, leading to turbulence. While increasing the air velocity can suppress disturbances and maintain cleanliness, it also raises operational costs. Therefore, to achieve the required level of cleanliness, the supply air velocity should be optimized to strike an appropriate balance.

On the other hand, ensuring stable performance of a clean booth also hinges on maintaining uniform airflow. If uniformity cannot be achieved, it indicates inconsistent air velocities—particularly along walls, where airflow may spiral around them. Under such conditions, attaining high cleanliness levels becomes exceedingly difficult. To preserve a consistent vertical laminar flow, the face velocity should be 3.360 m/s (a), with no velocity gradients; moreover, the return‑air grille on the floor must also exhibit no velocity variations. Both excessively low (e.g., 0.2 m/s) and excessively high (e.g., 0.7 m/s) velocities can induce turbulence, whereas a velocity of approximately 0.5 m/s helps ensure even airflow. Typical operating velocities generally fall within the range of 0.25 to 0.5 m/s.