The dust of air filter

At present, the air filter is more and more used in air conditioning and ventilation system, the service life is one of the indicators of concern in selection of air filter. But in practice it is difficult to predict the service life of air filter, so often used to evaluate its dust holding capacity. Dust holding capacity only qualitative but not quantitative reflection of the actual capacity of the air filter dust weight, and only test conditions and methods are the same, in order to evaluate different filter life according to the amount of dust data length (1).
Air filter Advisory Li Gong 15914315027
Due to various reasons, in the past ten years, the national laboratories and all the professional manufacturers rarely filter dust holding capacity test. (JG / T22-1999 "for air filter performance test methods" at present 2) the industry standard is being revised, the dust holding capacity test is one of the key amendments. This combination of JG / T22-1999, ANSI / ASHRAE52.1-1992 America (3), EN779:2002 (4) in Europe, Japan JISB9908:2001 (5) and four in the air filter performance test method is more representative of the standard of dust holding capacity definitions and test methods are introduced and comparative analysis, in order to help national standard revision work.
Dust holding capacity of 1 national standards in the paper
In JG / T22-1999, define the dust holding capacity is: subject to artificial dust filter in the total test termination conditions before the interception, which consists of artificial dust dust total quality by the filter efficiency of the average weight calculation; test method for dust holding capacity is: through the dust device artificial dust to send a certain amount of subjects to a filter and terminal filter (HEPA air duct is usually) test standard, until after the artificial dust transmission, remove the filter and terminal filter, respectively, weighing, the quality variation, to calculate the filter weight efficiency, repeated the above steps until the filter to the end resistance value, and then calculated the average weight and efficiency of the whole testing process, and finally by the efficiency of the average weight multiplied by the total quantity of dust from dust holding capacity of the filter.
EN779:2002 on the dust holding capacity definitions and test methods for dust holding capacity of JG / T22-1999 and ANSI / ASHRAE52.1-1992 are almost identical; only in the termination condition of dust holding capacity test and JG / T22-1999 is different, other content is the same; and JISB9908:2001 in addition to dust holding capacity test termination conditions and calculation method of inspection is not too the same, other similar content and JG / T22-1999. So the dust holding capacity of the standard test methods to test the termination condition and calculation methods there are some differences. Table 1 lists the standard dust holding capacity of each test termination conditions and calculation method.
The termination condition 2 dust holding capacity test
It is seen from table 1, test four standard termination has to reach the final resistance to judge on the basis of this condition, and the JG / T22-1999 and EN779:2002 only use this one judgment conditions, while the ANSI / ASHRAE52.1-1992 and JISB9908:2001 also used to reduce the weight efficiency of judging whether test termination.
2.1 to the end resistance as the termination condition test
For most filters, the resistance generally rise only to fall. In this case, can be directly used to achieve the final resistance and not to judge the dust holding capacity test whether to terminate, at this time, the amount of dust and end resistance was closely related to the size of the test, given the higher end of the resistance, the dust holding capacity the greater the value.
Determination of the resistance of the end there are two main conditions: 1) 2 times of initial resistance; 2) recommended by the manufacturer. Because of its structure and filter types, and some initial resistance is low, the early resistance if 2 times as the resistance, for these filters is clearly not fair; if recommended by the manufacturer only end resistance, end resistance is likely to cause different manufacturers at the same level of the filter is not the same, so every production house dust holding capacity is not comparable, which will give consumers in the choice of filter trouble. Therefore, in order to make the filter dust holding capacity index is more reasonable and norms, can consider to end resistance value of the unification, a level corresponding to a filter or a range of end resistance value, document 6 after analysis and summary, some suggestions are given finally resistance (Table 2), a good reference.
2.2 to reduce the weight efficiency as the termination condition test
For the low efficiency of filter made of coarse fibre materials with fluffy, because the media is more sparse, coarse dust particles are more plot, filter resistance increases to a certain value, the dust layer is penetrated and the dust from the bounce off the dust layer, the two dust, resulting in filter resistance is not increased but decreased. In this case, the termination condition judgment test must be used to reduce the weight efficiency to judge, i.e. ANSI / ASHRAE52.1-1992 b) and C conditions) or the condition in the JISB9908:2001 b), JG / T22-1999 and EN779:2002 have no provisions in this regard. Obviously, JG / T22-1999 as the national standard provision in this regard is not perfect, so the amendment has a corresponding increase in this aspects necessary.
3 methods of calculating the amount of dust
We can see from table 1, calculating method of dust holding capacity of JG / T22-1999, ASHRAE52.1-1992 and EN779:2002 are the same, is the product of artificial dust dust total quality and the filter efficiency of the average weight value recorded as dust holding capacity; JISB9908:2001 is the direct weighing the filter or filter through the end. The amount of dust.
According to the calculation method of JG / T22-1999, ASHRAE52.1-1992 and EN779:2002 standard, dust holding capacity to get the value must first find the average weight efficiency, however