What are the precautions for cleanroom air filter maintenance? What is the impact of high efficiency filter air speed on the cleanroom?

CleanroomAir FilterWhat are the maintenance considerations? How does the air velocity of a high efficiency filter affect a clean room?

In the electronics factory clean room, various types of high-efficiency filters are widely used, in the clean room and a variety of electronic factories in the electronics factory clean room routine maintenance. Air FilterThe maintenance of HEPA filters is a big expense, but the maintenance of air cleanliness is necessary for the pollution requirements of the production environment, what are the standards for the maintenance of HEPA filters and the installation and replacement of HEPA filters? In the process of packaging, transportation, installation and use of air filters in general and HEPA filters in particular, it is necessary to follow the standard requirements of HEPA filters manufacturers in order to ensure the effectiveness of the use of HEPA filters. All types of air filters in use for a period of time, because the filter media surface captures a variety of dust, thereby reducing the filtration efficiency of the air filter and air filter resistance, affecting the central air-conditioning unit or clean project supporting the high efficiency of air supply volume, cleanliness and use of efficiency, at this time it is necessary to replace the air filter in a timely manner, to ensure that the cleanliness of the air requirements. The following are some of the issues that should be noted in the maintenance of air filters:

1) All kinds of air filters and HEPA filters should not be allowed to tear or open the packing bag or packing film by hand before installation; the air filters should be stored in strict accordance with the direction standard marked on the packing box of HEPA filters; during the handling of HEPA filters, the filters should be lightly handled and put down, and violent vibration and collision should be avoided.

2) For HEPA filters, the installation direction must be correct: when installing the combined filter with corrugated plates in the vertical direction, the corrugated plates must be perpendicular to the ground; the connection between the filter and the frame in the vertical direction is strictly prohibited from leakage, deformation, breakage and leakage of glue, etc. The inner wall must be cleaned without floating dust, oil, corrosion and debris, etc. after the installation. After installation, the inner wall must be clean and free of floating dust, oil, rust and debris.

3) Inspection method: observation or white silk cloth wiping inspection.

4) Before the installation of high-efficiency filters, the electronic purification workshop must be comprehensively cleaned and wiped, and if there is any accumulation of dust inside the purification air-conditioning system, it should be cleaned and wiped again to meet the cleaning requirements. If the high-efficiency filter is installed in the technical mezzanine or ceiling, the technical layer or ceiling should also be fully cleaned and wiped.

5) The transportation and storage of the high-efficiency filter should be in accordance with the direction of the manufacturer's sign. During transportation, the filter should be held gently, prevented from violent vibration and collision, and should not be forced to load or unload.

6) Before the installation of high-efficiency filters, the packaging must be unpacked at the installation site for appearance inspection, including: whether there is damage to the filter paper, sealant and frame; whether the length, diagonal and thickness dimensions are in line with the requirements; whether the frame has any burrs and rust spots (metal frame); whether there is a product certificate of conformity, whether the technical performance is in line with the design requirements. Then in accordance with the national standard "electronic factory purification workshop construction and acceptance norms" [JGJ71-90] the provisions of the method of inspection, qualified should be installed immediately.

7) cleanliness level equal to and higher than 100 electronic clean room with a high efficiency filter, should be installed before the "electronic factory clean room construction and acceptance norms" [JGJ71-90] of the prescribed method of leakage detection, and meet the requirements of the regulations.

---- extended reading

For the clean room decoration in the clean room, airflow and air filtration system are two important links. So how does the air velocity of the high efficiency filter affect the cleanroom?

1, the impact of high wind speed on the clean room

After the renovation of the clean plant, if there are small particles of dust in the clean room, when the wind speed is high, the resistance must increase, which will affect the service life of the filter. After relevant tests, when the wind speed doubled when the dust transmission rate will increase by an order of magnitude. In terms of ordinary filters, the airflow through the filter material is usually in the 0.13 ~ 1.0m / s, then the filter resistance and filtering air volume of the relationship is like an upward arc, when the air volume increased by 30%, the resistance may increase by 50%. If the filter resistance is an important parameter for the clean room, then in the clean room plant renovation requires filter supply manufacturers to configure the resistance curve, so that the workshop can be a clean room. Configure the resistance curve so that the workshop can operate normally.

2, the impact of low wind speed on the clean room

After the completion of the construction of the clean room, if there are small particles of dust in the clean room, when the wind speed is low airflow will stay in the filter for a longer period of time, the dust touches the obstacles of a greater chance, more, filtering power will also be higher. After relevant tests, if the use of high-efficiency filters, when the wind speed is halved when the rate of dust through the rate will be reduced by nearly an order of magnitude. The use of electrostatic filters, dust stays in the filter for a longer time, then the higher the chance of being adsorbed. And when the wind speed changes , the wind speed becomes smaller, its filtering power will also change significantly. Therefore, on the electrostatic filters, designers in the planning of clean plant design should be well considered, try to reduce the amount of wind through each filter.

3. Cleanroom air filtration system

In the clean room decoration, the use of HEPA filters for air filtration, clean room, air filtration system is a very important part of the air filtration system should be used correctly for the clean room to provide a good production environment, which is particularly obvious in the ceiling height of the workshop is limited. However, it should also be noted that the use of low-grade filters, the use of high-pressure drop for a long time method of operation, the effect is not obvious.

4、Clean room airflow direction

There are many decoration solutions for clean rooms in workshops, such as: unidirectional airflow is only suitable for small spaces or sensitive areas, and is suitable for clean rooms with not too high requirements for cleanliness. In the unidirectional airflow of the clean room can be used in the equipment of the raised floor, in order to facilitate the flow of particles from the work area to the floor with small holes in the floor, and in the straight or horizontal airflow of the clean room can be set up in the lower part of the wall back to the air system, another practice is to choose the air injection equipment to isolate the ultra-clean area.