What is the FFU (laminar flow hood)?

What is the FFU (laminar flow hood)?
FFU (Fan Filter Unit) is a combination of fan and filter can also be called “Motorized HEPA filtration equipment”. FFU are usually installed in the supply end of the clean room, usually placed on the T-grid with gasket sealed. FFU upper part is the fan module, the lower part is the filter. Accordance with the requirements of cleanliness filters for different levels of efficiency (HEPA) or ultra-efficient (ULPA) filters provide clean air for the clean room. Fan modules overcome the resistance of the HEPA filter, but also to overcome the resistance of the whole cycle all channels of wind components in order to maintain the set running speed. Design and construction of FFU system with simple characteristics, flexible air flow adjustment, easy to change in the clean area, so the system has become one of the popular forms of industrial clean room.

FFU (laminar flow hood) Features:
1: Flexibility. Because limiting FFU self-powered, it is not limited by region. In a huge clean room can divided into zoning control according to need. Moreover, with the change in the semiconductor manufacturing process, plant layout is bound to be adjusted accordingly, flexibility FFU makes this adjustment easier, and will not bring secondary investments.

2: Reusability. If the FFU no need use at moment can be removed, sealed, safekeeping for next using.

3: Negative pressure ventilation. This is the unique characteristics of FFU, because of its own to provide anti-static, making relative to the clean air plenum plant negative, thus, the particles inside static pressure under pressure will not leak to clean area, make sealant becomes very simple and safe.

4: Shorten the construction period. Eliminating the need for the use of FFU duct fabrication and installation because the air duct in a clean project, takes up a lot of the construction period , any investor wants to invest as soon as possible to bring income , the choice of FFU become a possibility .

5: To reduce operating costs. Although the selection of FFU, the initial investment than with high ventilation duct, but during running, the outstanding performance of energy-saving, maintenance-free characteristics, with a 40% reduction in cycle operating costs.

FFU (laminar flow hood) external residual pressure (ESP): In a set speed, the total static pressure FFU (TSP), net of HEPA / ULPA filter resistance, that is external residual pressure (ESP), the unit is Pa. ESP is the FFU ability to overcome resistance in the clean room air circulation, either dimension the overall static TSP FFU and pressure or fan outside the machine module are required supply airflow volume, or no meaning.
Input energy (input power consumption): normal operation of FFU input voltage and input current the unit is W. Obviously, FFU that run at different condition of airflow volume and total static pressure, enter a different energy. Therefore, if you do not specify the operating point, the value of the input energy does not make sense.
Unit noise (noise level): according to the standard IES-RP-CC002, the normal operation of the FFU from the surface of the wind noise level at the center is 1.2mm below the unit is dB (A). FFU run at different conditions of airflow volume and total static pressure, different noise. Therefore, if you do not specify the operating point, the noise level does not make sense.

FFU (laminar flow hood) fretting (micro vibration): According to the standard IES-RP-CC002, FFU vibration amplitude and vibration rate at the maximum operating conditions point unit are mm and mm / s.

Uniformity air velocity (air uniformity): according to the standard IES-RP-CC002, the normal operation of FFU, the distance by measuring the surface side of the wind 150mm (6 ") of the horizontal surface wind speed, the average value of the obtained average wind speed. minimum and maximum wind speed and air deviation than is uniformity in units of + / - % standard IES-RP-CC002 FFU required air velocity at any point of its average wind speed deviation should be within + / - 20% or less .

Air Filter efficiency (filter grade): according to the European standard EN1822, HEPA Filter class from H10-H14, U15-U17. Or according to the American standard MIL-282 (HEPA), for 0.3um efficiency values ​​; according to the American standard IES-RP-CC007.1, for 0.12um efficiency values.