With the rapid development of science and technology, especially the development of military industry, aerospace, electronics and biomedicine industries, the development of clean technology also advances by leaps and leaps. The production of modern industrial products and modern scientific experiments require miniaturization, precision, high purity, high quality and high reliability. Electronic computer is one of the most representative miniaturization products, from electron tube to semiconductor separation device to integrated circuit and then to vlSI. In particular, the rapid development of large-scale integrated circuit and super large integrated circuit in the 1980s greatly promoted the development of clean technology. This paper focuses on the characteristics of FFU and control mode, combined with the modern electronic clean room for air cleanliness level requirements; The advantages of FFU application in clean room are analyzed, and the application of FFU in practical engineering cases is introduced.

Clean room FFU purification unit

I. Concept and principle

Fan Filter Unit (Fan Filter Unit), referred to as FFU, is a high efficiency Filter (HEPA) or ultra-high efficiency Filter (ULPA), micro Fan, shell combination of purification air conditioning end, it is used for turbulence and laminar flow clean room. FFU is usually used with the ceiling skeleton, according to the different choice of the ceiling skeleton with the corresponding FFU. The cleaning method of FFU can achieve a clean room with air cleanliness level between ISO3 and ISO9 (i.e. 1 to 1 million).

There are two common clean room air treatment methods, respectively MAU+AHU+HEPA (hereinafter referred to as AHU system) and MAU+FFU+DC dry coil (hereinafter referred to as FFU system). By comparing the two methods, it is concluded that FFU acts as a purification circulation unit in the purification air conditioning system, and the circulating air volume of the clean room is equal to the sum of the air volume of FFU in the clean room. The air in the clean room is sent into the clean room from the clean ceiling interlayer by FFU, and the circulating air is sent back to the ceiling interlayer through the return air lane; Circulating air through the return air lane and installed in the lane DC dry coil heat exchange.

Two, characteristics and application

Features of FFU: low energy consumption, low noise, convenient and flexible, saving space, easy to install.

Low energy consumption: from the perspective of FFU components, only the micro fan needs to consume energy, and the power of the micro fan is generally between 110W ∽ 190W, although in the selection of FFU, the initial investment is higher than the use of duct ventilation, but it in the late operation, outstanding performance of energy saving, maintenance free and other characteristics. Usually the circulation air volume of the clean room is very large, with an area of 100m2, clean room high of 3m, air cleanliness level requirements of ISO6 (i.e. 1000) clean room as an example: "clean workshop design code (GB500073-2001)" air cleanliness level of ISO6 clean room ventilation times of 50 to 60 times /h. Here, the air change times is 55 times /h, so the total circulating air volume is 16500CMH, and the fresh air volume is 3000CMH.

Scheme 1AHU system: MAU total pressure loss of 700Pa, power of 2.2kw; The total pressure loss of AHU is 1300Pa and the power is 15kW; The total power of the entire system is 17.2 kW.

In scheme 2FFU system, the total pressure loss of MAU is 800Pa and the power is 2.2kw. FFU(specification is 1200×600, air volume 1200CMH) has 14, a single FFU power of 190W,FFU total power of 2.66KW; The total power of the whole system is 4.86 kW.

Through the power of scheme 1, 2, the comparison, we draw a conclusion: head hepa filter in the system ACTS as the circulation wind ark and aggregation, and its power consumption is far smaller than AHU power cycle wind ark, accord with now strongly advocated the theme of the economical society, and to the manufacturer to save the cost of production to find a new direction.

Low noise: According to the National Standard of the People's Republic of China for Noise in Urban Areas, the industrial zone is 65dB (A) during the day and 55DB (A) at night. At present, the noise value of the fan on the market is generally in 65∽ 90DB (A), some will even reach 100DB (A) above, if the AHU system is easy to exceed the noise, resulting in noise pollution. The noise value of FFU is generally 45∽ 55dB (A), so there is no worry that its noise will exceed the standard.

Convenient and flexible: because FFU is built-in micro fan, it is not limited by the area, according to the need to partition control. With the continuous progress of science and technology, especially the rapid development of integrated circuit technology, the requirements for clean room air cleanliness grade are getting higher and higher, so the upgrade of clean room air cleanliness grade is an inevitable trend. If the original clean AHU MAU + + HEPA air conditioning mode, the so-called clean room upgrade means to rebuild, because reform is related to the construction difficulty and in the construction process of the destruction of the original ceiling and ceiling pipe, the final investment and reconstruction of were similar, but also for clean room temperature humidity control put forward higher requirements. In addition, it is not conducive to energy saving. But if the original system is MAU+FFU+DC dry coil air conditioning mode, because the total amount of clean room circulating air is the sum of THE air volume of FFU, and THE installation of FFU is with the ceiling skeleton, clean room upgrade is to increase the corresponding NUMBER of FFU on the clean ceiling. Because there are few air ducts in the system, the production and installation of air ducts are saved, the difficulty of construction is greatly reduced, and the construction period is greatly shortened. The market share of a product largely depends on the time of entering the market. The earlier the entry, the easier it is to occupy the market and see profits as early as possible. And any investor hopes to get returns in the shortest possible time, which can more reflect the advantages of FFU system.