Performance indicators of air filters

Performance indicators of air filters  

Filtration precision  

Refers to the maximum diameter of impurity particles allowed to pass.  The key to affect the filtration accuracy is the filter element. Different filters can be selected according to the needs of the rear components to achieve the corresponding filtration accuracy.  

Flow characteristic  

Refers to the curve of the relationship between the air flow through the filter and the pressure drop at both ends of the filter under a certain inlet pressure. In actual use, it is best to choose in the range of pressure loss less than 0.03mpa.  In the air filter, the main influence of flow characteristics is the body and filter element.  

The efficiency of water  

Refers to the ratio of separated water to the water content in the air inlet.  General requirements of air filter water efficiency is not less than 80%. Influence of water efficiency is mainly diversion plate.  

Air filters have different filtering efficiency with different concentration measurement.  

(1) Dust concentration of weight efficiency is expressed by mass concentration (g/m³)  

(2) Counting efficiency dust concentration is represented by counting concentration (PC /L)  

(3) Sodium flame efficiency sodium chloride solid particles as the dust source.  The concentration of sodium chloride particles was measured by photoelectric flame photometer.  Sodium flame efficiency is equivalent to counting efficiency.  

Filter resistance  

The resistance of the new filter is called initial resistance at rated air volume;  At the rated air volume, the filter dust capacity to reach enough to clean or replace the filter material resistance is called the final resistance.  

Dust capacity of filter  

When the resistance of the filter reaches the final resistance at the rated air volume, the total mass of the dust particles contained is called the dust capacity of the filter.  

Selection principle  

According to the specific situation to reasonably choose the right air filter, the selection principle is as follows:  

1. According to the indoor requirements of clean and purification standards, determine the efficiency of the last stage of the air filter, reasonably select the combined series of air filters and the efficiency of all levels.  Such as indoor requirements of general purification, can use a primary filter;  Such as indoor requirements of medium purification, you should use the primary effect and medium effect two filters;  If the indoor requirements of ultra-clean purification, it should use the primary effect, medium effect and high efficiency three stage purification filter, and should reasonably and properly match the efficiency of the filter at all levels, if the efficiency difference between the two adjacent filters is too large, the former filter will not play a protective effect on the filter at the last level.  

2. Correctly measure the dust content and dust particle characteristics of outdoor air.  Because filters filter and purify outdoor air into the room, so outdoor air dust content is a very important data.  Especially in the multi-stage purification and filtration process, the pre-filter should be selected after considering the use environment, spare parts cost, operation energy consumption, maintenance and supply and other factors.  

3. Correctly determine filter characteristics.  The characteristics of the filter are mainly filtration efficiency, resistance, penetration, dust capacity, filtration wind speed and air volume.  In the case of allowable conditions, should be as far as possible to choose efficient, low resistance, large dust capacity, moderate filtering wind speed, large processing air volume, convenient manufacturing and installation, low price of the filter.  This is the economic analysis needs of one-time investment and secondary investment and energy efficiency ratio when choosing air filters.  

4. Analyze the properties of dusty gas.  The nature of dust gas related to the selection of air filter is mainly temperature, humidity, acid and alkali and the number of organic solvents.  Because some filters are allowed to be used at high temperature, and some filters can only work at room temperature and humidity, and the number of acid and alkali containing dust gas and organic solvents have an impact on the performance and efficiency of air filters.