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    Home > Active Ingredient News > Drugs Articles > Product knowledge of air filter

    Product knowledge of air filter

    • Last Update: 2014-04-10
    • Source: Internet
    • Author: User
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    Key words of product knowledge introduction of air filter: air filter, filter, clean sampling vehicle, purification equipment, non partition, DOP leak detection filter, purification engineering, pharmaceutical machinery, chemical equipment, pharmaceutical equipment, air supply outlet, laboratory equipment, biological equipment Product knowledge introduction of air filter 1 Objective: to make the polluted air clean to the state needed by production and life, that is to make the air reach a certain degree of cleanliness 2 Classification: 1) human comfort: air purification centering on human health The problem of indoor air quality is "building syndrome" In a closed air-conditioning building, all kinds of building materials, office electrical appliances and living electrical appliances emit organic volatiles, bacteria, dust and so on The human body will produce discomfort and raw glass 2) the functionality of industrial production: air purification around the requirements of industrial product quality Pharmaceutical factories (including preparation rooms in hospitals) should prevent the pollution of microorganisms and impurities; electronic factories and chip factories are very sensitive to dust particles Sufficient and purified air can be supplied to achieve the specified cleanliness 3 Function: it is an indispensable equipment to create a clean air environment The clean air sent into the room mainly depends on the air filter to catch the dust particles suspended in the air 4 Place of use: around the two main purposes of human comfort and industrial production functionality, air filters are used in: 1) office buildings, commercial hospitals, airport terminals and other buildings equipped with central air conditioning system 2) Pharmaceutical factories, chip factories, electronic products factories and other factories with high requirements for clean production environment ·3) , installed in the household electrical products, mainly in: A, household air conditioning: window machine, split machine, cabinet machine, ceiling machine; B, air purifier, also known as air freshener; C, vacuum cleaner; D, exhaust fan or ventilator; E, oil fume extractor; 4), installed in the air conditioning system of the car, including cars and buses of course Note: the three filters (air filter, fuel filter and engine oil filter) of automobile engine are called automobile filters We are talking about air conditioning filters for people sitting in cars 1、 Main parameter 1: rated air flow the air flow through the filter in a certain volume in a unit time In China, the air flow is generally expressed in m3 / h, while in foreign countries, it is also expressed in cubic foot per minute, i.e FT3 / MIM cubic foot / minute, which is calculated as: 1cfm ≈ 1.7m3/h Of course, we hope that under the same windward section, the larger the air volume that the filter can pass, the better, which means that it has a large amount of filtration, but it is mainly determined by its filter material and structure 2 Surface velocity and filter velocity refer to the velocity of air flow on the windward section, generally expressed in M / S; surface velocity = air volume ÷ windward section filtering velocity refers to the velocity of air flow on the filter material, generally expressed in cm / S; filtering velocity = air volume ÷ filtering area Filter area refers to the area of the filter material used Only when the filter material is flat and perpendicular to the air flow direction, the windward sectional area of the filter is the same as the filter area, and the filter material installed in the vacuum cleaner is usually discount shaped English wind speed units are also used in foreign countries: FPM (foot per minute), 1000 FPM ≈ 5.08m/s 3, filtration efficiency 1), definition: filtration efficiency = dust collected by the filter ÷ upstream air dust content = (upstream air dust content - downstream air dust content) ÷ upstream air dust content The definition of efficiency seems simple, but its meaning and value are closely related to the test methods The efficiency values obtained by different test methods cannot be directly compared Therefore, when talking about efficiency, we must explain the efficiency of which test method is used In foreign countries, permeability ratio or penetration ratio are sometimes used to express filtration performance Transmittance = 1-filtration efficiency 2) Specification: A Chinese specification: course medium high medium sub HEPA B European specification: g-f-h-u grade IV American specification: c-l-m-h-u grade V A weight method: arestance The test dust source is standard dust with large particle size and high concentration According to the American Standard, "road dust" in Arizona desert area is used According to the Japanese standard, "loam" in Kanto area of Japan is used According to the Chinese standard, the dust on the Loess Plateau is used Adding the specified amount of fine carbon black and short fiber into the specified dust will become the dust source for the test This method can measure the weight of the dust passing through the filter, or the ratio of the amount of dust collected on the filter to the total dust, and calculate the filtering efficiency of the weighing method The weight method is applicable to the measurement of low efficiency filters, which are generally used as primary filters in central air conditioning system b The colorimetric method dust spot originated from the traditional test method in the United States, which is not used in China The efficiency is calculated by measuring the luminous flux on the filter paper of the sampling point This method has been formally abolished in Europe C The standard dust source of China is "atmospheric dust" in the natural atmosphere The "amount" of dust is the total number of particles with a particle size greater than or equal to The instrument for measuring dust is ordinary optical or laser dust particle counter The efficiency value is the initial efficiency of the new filter The air dust counting method is used to measure filters for general ventilation Its efficiency value only represents the performance of the new filter China's efficiency classification is based on the air dust counting method The standard of counting method in China is earlier than that in Europe and America, but the method is relatively rough It is based on domestic counter and corresponding measurement technology level in 1980s Standard: gb12218-89 d American counting method particle efficiency, ashrae52.2 is used in the United States The test-bed is similar to the weight method and the colorimetric method The high concentration test dust is also similar to the weight method and the colorimetric method 3) DOP method is originated from the United States and has been widely used in the world The dust source was DOP (dioctyl phthalate, a kind of plasticizer commonly used in plastic industry) droplet "Quantity" refers to the turbidity degree of the air containing DOP The instrument for measuring dust is a photometer The filtration efficiency of the filter to DOP particles is determined by the turbidity difference of the gas sample The DOP liquid is heated to steam, and the steam condenses to 0.3 μ m micro droplets under specific conditions, and the mist DOP enters the air duct The turbidity of the gas sample before and after the filter is measured, and the filter efficiency for 0.3 μ m dust is judged DOP method has a history of more than 50 years This method was used to measure Zui in the world In the early days, it was considered that the filter was difficult to filter 0.3 μ m dust Zui, so it was stipulated to use 0.3 μ m dust measurement filter There is benzene ring in DOP, which is suspected to be carcinogenic, so many laboratories use substitute with similar performance but without benzene ring, such as DOS, but the test method is still called "DOP method" The DOP method for measuring filters is also known as the "hot DOP method" The corresponding "cold DOP" refers to the spray nozzle using compressed air to blow bubbles in DOP liquid, splashing to produce fog like artificial dust Relevant standards: mil-std-282 4) The MPPs law (most transparent particle size) is generally used in Europe, the United States in addition to the national defense industry, and individual enterprises in China It can measure almost all HEPA and ULPA filters, and has the trend of replacing traditional methods People once thought that the filter efficiency Zui of 0.3 μ m dust was low, so when evaluating the filter, the filter efficiency of 0.3 μ m dust was taken as a typical value There are many methods to produce and measure 0.3 μ m dust, so there are such methods as DOP, oil mist, sodium flame, etc It is found that the laser particle counter, which can measure 0.1 μ m particle size dust, can not only measure the dust concentration, but also the particle size of each dust, so that the typical value of low efficiency Zui can be easily measured, and the corresponding typical value of dust particle size is MPPs Size, Zui easy to penetrate particle size) The value of low efficiency Zui corresponding to MPPs is MPPs efficiency Relevant standards: American est-rp-cc-007.1-1992, European EN 1822-5:2000 5) resistance 1 Definition: when the air flow passes through the filter, the filter will form resistance to the air flow, and the air volume will reduce 2 The composition of resistance The resistance of the filter consists of the resistance of the filter material itself and the structural resistance of the filter We hope that the smaller the resistance of the filter, the better, because the greater the resistance, In order to achieve the rated output air volume, the power of the motor should be increased If the power of the motor is too small, it will produce howling All these should be solved reasonably, and appropriate filter materials should be selected 3 Initial resistance: the resistance of the new filter is called initial resistance 4 Final resistance: the resistance when the filter is to be scrapped is called final resistance, The selection of final resistance is directly related to the service life of the filter, the range of air flow and air volume, and the energy consumption of the system 5 Resistance unit: Pascal 1pA = 1n / m2 British unit: in WG water gauge metric unit: mmh2o mmh2o 1mmh2o = 9.8 PA in WG = 250pa
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