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Basic parameters and selection of FFU

The general specifications for making the equipment are as follows.

◆Size: matching the size of the overhead plate.

◆Material: environmental requirements, cost considerations.

◆Surface wind speed: 0.35~0.45m/s, with large differences in power consumption.

◆Static pressure: to overcome the demand for wind resistance.

◆Filters: according to the demand of cleanliness level.

◆Motor: power supply characteristics, power, bearing life.

◆Noise: to meet the requirements of a clean room on noise.

Basic parameters

1、Face air speed

Generally, between 0-0.6m/s, such as five-speed, the corresponding wind speed of each gear is roughly 0.3-0.35-0.4-0.45-0.5m/s, and the induction speed is roughly 0-0.6m/s.

2、Power consumption

AC systems are generally in the 100-300 watts; DC systems are in the 50-220 watts. The DC system is 30-50% smaller than the AC power consumption.

3、Uniformity of airspeed

This refers to the uniformity of air velocity on the FFU surface, which is particularly stringent in high-level clean rooms, otherwise, it is very easy to cause a disturbance. When testing this parameter, depending on the size of the FFU surface, 6-12 points should be evenly selected to test the surface airspeed, and the average of the maximum and minimum values should not exceed ±20%.

4、Static pressure outside the machine

Also known as residual pressure, this parameter is related to the service life of FFU and is closely related to the fan, generally required at a surface wind speed of 0.45m/s, the static pressure outside the machine is not less than 90Pa.

5、Total static pressure

The total static pressure (TSP) = external static pressure (ESP, the static pressure provided by the FFU to overcome the resistance of external ducts and return ducts) + filter pressure loss (the value of the filter resistance at the wind speed) at a certain wind speed. (the resistance value of the filter under the airspeed).

6、Noise

The general noise level is between 42-56 dBA, when using it, we are more concerned about the noise level at the surface air speed of 0.45 m/s and the static pressure outside the machine at 100 Pa. For FFU of the same size, DC is 1-2 dB smaller than AC.

7、Vibration rate: generally less than 1.0mm/s.