In clean production rooms, FFU is usually used at the end of the purification air conditioning system and belongs to the last air filtration device that ensures the cleanliness level of the cleanroom.
The A-PLUS FFU is mainly composed of four parts:
1. Box
Its material is usually galvanized aluminum alloy coated steel plate, aluminum alloy, and stainless steel. The first function is to support the fan and the air guide ring, and the second is to support the diffuser plate;
2. Diffuser plate
An air flow balancing device, which is placed inside the box, around the bottom of the fan;
3. Fan
There are three types: single-phase AC (AC/1Phase), DC (EC/1Phase), and three-phase AC (AC/3Phase);
4. Control components
For AC FFU, the commonly used speed regulators or infinitely variable speed regulators are used; for DC systems, the control chip is embedded in the motor, and remote control is realized through dedicated control software, computers, control gateways, and network lines.
Basic parameters of A-PLUS FFU
1. Air velocity
Generally between 0 - 0.6 m/s. If it is five-speed regulation, the corresponding air velocities for each speed are approximately 0.3 - 0.35 - 0.4 - 0.45 - 0.5 m/s. If it is infinitely variable regulation, the speed range is between 0 - 0.6 m/s.
2. Power consumption
The AC system is generally 100 - 300 watts; the DC system is 50 - 220 watts. The DC system has 30 - 50% less power consumption than the AC system.
3. Noise
The noise of domestic brand FFU is generally between 42 - 56 dBA. When using it, the noise at a face air velocity of 0.45 m/s and an external static pressure of 100 Pa is of particular concern. For FFU of the same specification and size, the DC type is 1 - 2 decibels smaller than the AC type.
4. Air velocity uniformity
It refers to the uniformity of the FFU's face air velocity. Good clean rooms have particularly strict requirements for this parameter; otherwise, it is easy to cause turbulence. The design and craftsmanship of excellent fans, filters, and diffusers determine the quality of this parameter. When testing this parameter, select 6 - 12 points on the FFU's outflow surface to test the air velocity, and the maximum and minimum values should not exceed ±20% (the EC-FFU system of A-PLUS can achieve ±10%).
5. Vibration rate
Generally less than 1.0 mm/s.
6. External static pressure
Also known as residual pressure, this parameter is related to the lifespan of the FFU. It is closely related to the fan and generally requires that the external static pressure be not less than 90 Pa at a face air velocity of 0.45 m/s.
7. Total static pressure
Also known as total pressure, it is the static pressure that the FFU can provide at maximum power and zero air velocity. Generally, the AC FFU is around 300 Pa, and the DC FFU is 500 - 800 Pa. Under a certain air velocity, it can be calculated as follows: total static pressure (TSP) = external static pressure (ESP, the static pressure that the FFU provides to overcome the resistance of external pipes and return air ducts) + filter pressure loss (the resistance value of the filter at this air velocity).
Basic dimensions of A-PLUS FFU:
|
Basic module (i.e., the centerline distance of the ceiling joists) |
Size of the FFU enclosure（mm） （W×L） |
Filter size（mm）（H×W) |
|
|
Metric system（mm） |
The commonly referred to imperial system（ft） |
||
|
1200×1200 |
4×4 |
1175×1175 |
1170×1170 |
|
900×1200 |
3×4 |
875×1175 |
870×1170 |
|
600×1200 |
2×4 |
575×1175 |
570×1170 |
|
600×900 |
2×3 |
575×875 |
570×870 |
|
600×600 |
2×2 |
575×575 |
570×570 |
1. The width and length dimensions mentioned above are already standardized among various domestic and foreign manufacturers. However, the thickness varies among different manufacturers.
2. Besides the above basic dimensions, non-standard specifications can be customized. However, in terms of delivery time or price, using standard specifications is more appropriate.
