1. Pre-filter
It is usually made of cleanable polyurethane foam. The primary concern is to prevent any damage to the filter caused by debris resulting from construction, maintenance, or other unexpected situations.

II. Shell Body
The main materials include aluminum plates, aluminum alloys, hard plastics, stainless steel, etc. Different manufacturers and different application environments require different selections. The thickness is approximately 1.2 to 2.0, and depending on the thickness, some can accommodate people.

III. Air duct connection components
In environments with a lower cleanliness level (≤1000 level, Federal Standard 209E), there is no static pressure box on the ceiling. The FFU with air duct connection components makes the connection between the air duct and the FFU very convenient.

IV. Motor
Currently, both AC motors and DC motors are used in FFUs. DC motors have a large volume, high cost, and are easy to control. However, they have higher energy consumption. AC motors have a small volume, low cost, and require corresponding skills for control. They have lower energy consumption. The lifespan of the motors currently used in FFUs is approximately 4 to 100,000 hours. Some excellent motors have corresponding technologies, such as oil-free lubrication, sealed bearings, overheating protection, and significantly improved commutator lifespan.

V. Impeller
There are two types of impellers: forward inclination and backward inclination. Forward inclination is beneficial for adding the directional movement of the airflow and enhancing the ability to remove dust. Backward inclination is beneficial for reducing energy consumption and noise.

VI. Airflow balancing equipment
With the continuous spread of FFUs, most manufacturers have begun to install airflow balancing equipment to adjust the airflow of FFUs and then improve the airflow distribution in the cleanroom. Currently, this balancing equipment can be divided into three types: one is a orifice plate (as shown in Figure 6), mainly adjusting the airflow of the FFU through the distribution of holes on the plate. Another is a grille (as shown in Figure 7), mainly adjusting the airflow of the FFU through the density of the grille. The other is a power curve (as shown in Figure 8), mainly inducing the movement of the airflow through the shape of the curve, and also adjusting the airflow through the distribution of holes on the curve.

VII. Filter
The filters used in FFUs are the same as those used in cleanrooms. This will not be elaborated here.

VIII. Metal protective net
The metal protective net mainly serves to protect the filter. Most of them are anti-static.

IX. Knife edge
When FFUs are used in some special occasions, FFUs with knife edges can use liquid槽 sealing， which can meet the requirements of high sealing performance.

X. Control unit
The control of FFUs can be roughly divided into multiple-level switches， continuous adjustment， computer control， etc. The functions achieved include single-unit control， zone control， alarm， and display of operating status.

Aireplus official website： www.aireplus.com.cn