Classification Specifications And models Of Air Filters
Classification Specifications And models Of Air Filters they are important references for early purification projects.Nowadays, with the progress of the times and further exploration of scientific research, the specifications are "High Efficiency Air Filter" (GB13554-2020) and "Air Filter" (GB/T14295-2019).
The main classification of air filters is clarified in the specification: coarse-efficiency filter, medium-efficiency filter, medium-efficiency filter, sub-high-efficiency filter and high-efficiency filter.
In general ventilation projects, coarse-efficiency filters and medium-efficiency filters are more common. Only in purification projects are high-efficiency filters, sub-high-efficiency filters and high-efficiency filters often involved. Regarding the performance classification of coarse-efficiency filters, medium-efficiency filters, medium-efficiency filters, and sub-high-efficiency filters, you can refer to the table below, and we will not explain it further here.
----------------------------high-efficiency filters, sub-high-efficiency filters and high-efficiency filters----------------------------
High efficiency filter:
High-efficiency filters are mainly divided into two types: bag-type high-efficiency filters and tube (cylinder)-type high-efficiency filters. They are generally installed in combined air conditioning units, among which bag-type high-efficiency filters take up more space than tube (cylinder)-type high-efficiency filters.
Therefore, for projects with relatively compact air-conditioning rooms, we generally choose tube (cylinder) high-efficiency filters. However, in engineering applications, we find that the filter tubes of tube (cylinder) high-efficiency filters are easy to fall off, which will affect the filtration effect. .
Compared with tube (cylinder) high-efficiency filters, the advantages of bag-type high-efficiency filters are particularly obvious. They have the characteristics of large air volume, large dust holding capacity, low resistance, and long service life. Therefore, they are obtained in actual projects. a wider range of applications.
----------------------------Sub-high efficiency filter----------------------------
Sub-high-efficiency filters are mainly divided into two types: filter paper pleated type and filter tube type. The shape and processing technology of the pleated filter paper sub-high-efficiency filter are basically the same as those of the high-efficiency filter with partitions; while the filter tube-type sub-high efficiency filter is the only filter of this level that does not use glue. Due to the production process and materials, No glue has been used, so this type of sub-high efficiency filter generally does not produce secondary pollution and is more suitable for use in medical clean room projects.
For low-resistance sub-high-efficiency filters, in actual projects, designers generally design them inside the combined air-conditioning unit or at the end of the air supply duct.
Because of its small initial resistance, it is more advantageous to select a fan for the purification air conditioning system, which can effectively control the noise problem of the unit. Some people even directly replace high-efficiency filters with sub-high-efficiency filters in projects, although they are used in 100,000-level or even 10,000-level purification workshops.
Because the use of sub-high-efficiency filters directly replaces high-efficiency filters, although it saves costs and solves the noise problem, it also increases the self-cleaning time of the clean room and the problems of inability to accurately control the cleanliness, sedimentation bacteria, and planktonic bacteria values. come behind.
Therefore, regarding the use of sub-high-efficiency filters, I still hold an attitude of using intermediate filtration. To prevent the trouble of failing the final clean room acceptance.
----------------------------High efficiency filter----------------------------
For the performance parameters of high-efficiency filters, please refer to the table below.
Among them, the sodium flame method is used for the efficiency of Class A, B, and C high-efficiency filters, and the counting method is used for the efficiency of Class D high-efficiency filters.
High-efficiency filters are classified according to the material of the separator and can be divided into two categories: high-efficiency filters with partitions and without partitions.
In addition, the separators between the filter papers of the high-efficiency filter without partitions are made of hot melt glue thread, silk thread, glass fiber paper strips, etc. It is precisely because the gap between the filter papers becomes smaller, so under the same rated air volume, the thickness of the filter Compared with high-efficiency filters with partitions, the efficiency is reduced by 1/3 to 2/3. For projects with limited mezzanine space, using high-efficiency filters without partitions is a very good choice.
----------------------------High efficiency filter specifications and models----------------------------
At present, there are three main types of mainstream high-efficiency filters in China: 320 series, 484 series, and 630 series.
In addition, the 968*484 series is often used in projects, with a rated air volume of 2000m³/h.
The rated air volume of the 320 series high-efficiency filter is 500m³/h; the rated air volume of the 484 series high-efficiency filter is 1000m³/h; the rated air volume of the 630 series high-efficiency filter is 1500m³/h.
The rated air volume of the air filter is the air volume at a certain filtration speed. In order to reduce the total system resistance of the purified air conditioning system in the design, when selecting the air outlet of the high-efficiency air filter, it is generally selected at 70% to 80% of the rated air volume.
"Design Standard for Clean Plants in the Pharmaceutical Industry" GB 50457-2019.
During the design process, designers refer to this specification as a mandatory provision.
The production and development of Classification Specifications And models Of Air Filters is closely related to the development of the military and electronic industries. Asbestos fiber filter paper, used as the filter material for the smoke filter layer of military gas masks, was already available at the end of World War I. Glass fiber filter material for air filtration was patented in the United States in October 1940. In the 1950s, the United States conducted in-depth research on the production process of glass fiber filter paper, which led to the improvement and development of air filters. HEPA filter paper produced using fine glass fibers in the 1970s has a filtration efficiency of up to 99.999% for 0.3um particles. Judging from the development of foreign air filter materials, before the late 1970s, the classification of air filter materials was roughly divided into two filtration levels: primary efficiency and medium and high efficiency. The filtration efficiency of HEPA filter material is generally required to be higher than 99.97%, so people think that it can already meet the usage requirements.
With the progress of society and the improvement of people's living standards, filters, especially high-efficiency particulate air (HEPA) filters and ultra-low penetration air (ULPA) filters, are increasingly used in various fields, such as microelectronics, pharmaceuticals Industry, hospitals, food industry, cosmetics industry, environmental protection industry, nuclear industry and military fields, etc. The research and development of air filter materials has made great progress, but at the same time, people have also put forward higher requirements for air filter materials.
Since the 1980s, with the emergence of new testing methods, improvements in use evaluation technology, and increased requirements for filter materials, it has been discovered that HEPA filter materials still have some problems. So a new generation of ULPA filter material came into being, with a particle filtration efficiency of 0.12um higher than 99.999%. After entering the 1990s, Lydall Company in the United States readjusted the classification of filter materials from the perspective of application and divided filter materials into four levels: Class1000ASHRAE; Class2000Prefiher/Hospital; Class3000HEPA; Class5000ULPA. The latter two are high-efficiency filter materials.
Most of the filter materials used in military protective equipment are blue asbestos cellulose, glass fiber cellulose or single-component glass fiber filter materials. Because asbestos is a carcinogen and has adverse effects on human health, Western countries stopped using asbestos filter materials in the 1970s. With the limitation of combustible content of filter materials, the use and development of glass fiber cellulose filter paper, which was once widely used, has also been restricted. However, single-component glass fiber is difficult to achieve a high filtration level due to its simple structure. Since the 1980s, our country's scientific researchers have developed glass fiber HEPA filter paper and ULPA filter paper through unremitting efforts.
----------------------------Future development trends----------------------------
1. Worldwide, glass fiber filter materials still dominate high-efficiency air filtration materials, but membranes and electrostatic enhancement media have replaced it in some aspects. It has been suggested that membranes will replace fiberglass filtration materials once their filtration performance at low airflow resistance is improved.
2. The development of high temperature resistant filter materials will be accelerated. Glass fiber composite inorganic membrane filter materials, metal fiber and ceramic fiber filter materials have been applied, and new metal and ceramic sintered filter materials have also made great progress.
3. Worldwide terrorist incidents, as well as the occurrence of public health emergencies such as SARS and avian influenza, have also sounded the alarm to all countries. Countries have researched and developed new broad-spectrum protective filter materials to ensure the protection of various aerosols ( Especially effective protection against bioaerosols).
Keywords: glass hepa media | h10 hepa filter efficiency | h12 hepa filter efficiency | h13 efficiency | high efficiency ac filter | high efficiency air conditioner filter
