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What is the common sense of air filter?

2022-02-25 Page view : 132 views

Filter Material

The type of air filter can be divided into chemical fiber non-woven filter material, synthetic fiber filter material, glass fiber filter material, activated carbon filter material, imported cotton fiber, long fiber series, etc.


1.) Chemical Fiber Non-Woven Filter Material

The scientific name is polyester fiber, commonly known as non-woven fabric. Non-woven fabric has the technical characteristics of wide application, mature technology and good stability.

The manufacturing process is made of melt blown, acupuncture, spunlace, spunbond and other processes through multiple processes. Compared with other filter materials of the same level, it has stable quality, larger dust holding capacity, strong moisture resistance, long service life and economical Durability and so on. However, non-woven fabrics also have some disadvantages, that is, the resistance is too large, and they are not environmentally friendly (cannot be incinerated or decomposed). Non-woven fabrics are also the earliest used filter materials, with mature technology and low production costs. Although new filter materials have emerged in an endless stream in recent years, due to high production costs and high technical standards, it is difficult to popularize. Due to this, in the lower coarse and medium-efficiency filtration environment, the non-woven filter material still has an irreplaceable position due to its low price and high quality. In recent years, due to the continuous progress of technology, the appearance of composite non-woven fabrics has greatly improved the cheap and low-end image of non-woven fabrics, and the efficiency has reached sub-high efficiency.

At the same time, non-woven filter materials can also be used for filtration in places with relatively low requirements for air cleanliness.


2.) Synthetic Fiber Filter Material

Synthetic fiber filter material can completely replace non-woven fabrics and glass fiber covering a full range of filter products in coarse, medium and high efficiency (G3-H13) in general filtering environments. It is an emerging filter material and the main development direction of future filter materials. Compared with other filter materials of the same level, it has the advantages of low resistance, light weight, large capacity, environmental protection (can be incinerated), and moderate price.

Due to the relatively backward domestic processing technology and technical means in the 1990s, the synthetic fiber filter materials at that time were mainly imported. Although the imported filter material has excellent performance and high quality, it is expensive. In recent years, with the rapid development of China’s domestic air purification industry and the rapid growth of market demand, some synthetic fiber filter materials produced in China have the characteristics of good performance, environmental protection and strong stability, and at the same time, our customers can enjoy cost-effective Moderate product.


3.) Glass Fiber Filter Material

Glass fiber filter material is mainly made of glass fibers of various thicknesses and lengths through special processing technology. Because glass fiber has the characteristics of high temperature resistance, high efficiency, long service life and environmental protection. And in some special circumstances, only the wave line can be competent. Widely used in bag filters and high efficiency filters for general ventilation systems.

Glass fiber filter materials and synthetic fiber filter materials are mainly imported, and although the performance is good, there is an actual situation that the price is high. However, glass fiber filter materials are still widely used in places and environments with high requirements for air filtration due to their stable performance, high efficiency, large capacity, high temperature resistance, and long service life.


4.) Imported Cotton Fiber

Imported cotton fiber is actually a new type of filter material that is mixed with chemical fiber and cotton fiber. It is mainly used in the pre-filtration of course-efficiency and general air-conditioning systems. It has the characteristics of small resistance, large dust capacity, light weight, stable performance, economic and environmental protection and so on. It is an ideal product to replace non-woven fabrics in future filter equipment.


5.) Activated Carbon Filter Material

The characteristic of activated carbon is to remove the odor in the air.

Activated carbon filter material refers to the activated carbon used in coarse, medium and high-efficiency air filters. There are two main forms of activated carbon filter media – granular and activated carbon filter cotton. Because the function of activated carbon is to remove odors, the filtration efficiency is not emphasized. in use. Generally, it must be used with independent coarse and medium efficiency filters.

Some activated carbon materials can be regenerated, so although the price is more expensive than the general coarse filter, the cost of use can still be reduced if a reasonable cycle can be used alternately.


6.) Long Fiber Series


Chemical fiber, synthetic and glass fiber filter materials all have corresponding long fiber varieties, which are mainly used for filtration of 10μm large particles (such as dust) in special occasions (such as spraying workshops). Large dust holding capacity, high capture rate, can be made into filter pad or flat structure, easy to pave and replace, glass fiber and a small amount of chemical fiber varieties can withstand high temperature.


Medium Efficiency Filter

It is essential for general ventilation and air conditioning systems, and is the main force for filtering air.

The bag type is mainly to meet the requirements of large air volume and low resistance. The correct way to use the bag filter is to install a layer of pre-filtering device at the front end of the bag filter, generally using a disposable paper frame or metal frame plate filter. Metal plate filters are strong and durable, can be washed repeatedly, and are widely used today. This effectively prevents the bag filter from being directly exposed to harsh environments.

During our regular return visits to customers, we found that some users, in order to save costs and reduce installation procedures, generally use the bag filter directly as the first-stage filtration after the paper frame filter at the front end of the bag filter has reached its service life. As a result, the use environment of the bag filter is harsh and the service life is shortened, so it cannot be used according to the original design requirements of this product. This situation should be avoided as much as possible. On the surface, although the purchase cost of adding a filter increase, but through the actual operation of the air conditioner, the installation of the front filter can prolong the replacement cycle of the bag filter. In the long run, the total maintenance cost will be reversed. Reduced.


High Efficiency Filter

The application scope of high-efficiency filters is mainly the terminal filtration of medical, civil or industrial clean places with high requirements for cleanliness in industries such as electronics, semiconductors, precision machinery, pharmaceuticals, hospitals, and food.

Since the high-efficiency filter is generally used as the filter end, the requirements for the high-efficiency filter are also the most stringent, of course, additional “care” is required.

First of all, we want to remind customers that to prolong the service life of the high-efficiency filter, the most fundamental and easiest way is to keep the dust out of the pre-filter. That is to say, it is ensured that the air flow that the high-efficiency filter contacts is the air filtered by the pre-filter, the coarse-efficiency filter, and the medium-efficiency filter. At this time, the air should reach the standard of 99.95% with smaller dust particles and lower pollution.

What needs to be explained here is that the replacement of the pre-filter generally does not need to stop production or stop other normal work plans and arrangements. After installation, no debugging is required to ensure the normal operation of the air-conditioning fresh air equipment. So experienced clients will focus on pre-filters. For highly clean areas such as class 10000 and class 100000 clean workshops or operating rooms, F8 filtration (95% colorimetric method) can be used for pre-filtration. In this way, the service life of the terminal high-efficiency filter can generally reach 5 years. In foreign projects and domestic new projects. F8 filters are the most common pre-filters for non-uniform flow cleanrooms. For clean workshops of class 100, 10 or higher in chip factories, the common efficiency level of pre-filters is H10 (MPPS85%), and many new projects simply choose HEPA (the filtration efficiency for 0.37m particles is ≥99.97%). In the past clean room air-conditioning system design in China, the common configuration of the filter is: coarse-efficiency → medium-efficiency → high-efficiency. At that time, the service life of the terminal high-efficiency filter was only 1-3 years, and the worst was only a few months. It can be seen that the pre-filtration efficiency determines the service life of the end filter.

In some cases, the regulations on the use of high-efficiency filters are not based on the consideration of resistance, but other factors. If there is hydrofluoric acid in the workshop, and the workshop air conditioner is not a fresh air system, the glass fiber filter paper of the high-efficiency filter will be affected. Corrosion of return air. For safety, the high-efficiency filter must be replaced regularly. At present, some domestic hospitals and pharmaceutical factories will actively replace the high-efficiency filter after the rainy season every year. The main purpose is to prevent any possible mold contamination on the filter. Some national tertiary hospitals, biological laboratories of pharmaceutical factories and laboratories dealing with dangerous goods will use new high-efficiency filters in order to ensure safety and reliability before starting a new biological subject.