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Standard air filter dust holding capacity analysis
Introduced JG/T22- 1999, ANSI/ASHRAE52.1- 1992, EN779: 2002, JISB9908: 2001 and other domestic and dust holding capacity of four standard definition and test method, the termination dust holding capacity test conditions and calculation methods were compared, that the shortcomings of our standard, and gives suggestions for improvement.
Present, Air Filter In the application of air conditioning and ventilation systems are more and more people choose air service life is Filter When one of the indicators of concern. However, in practice very difficult to predict the service life of air filter, it is often used to evaluate its dust holding capacity. Dust holding capacity can only be qualitative rather than quantitative reflect the actual capacity of the air filter dust weight, while only the test conditions and methods are the same, to dust holding capacity according to the data to evaluate the different filter length of life [1].
A variety of reasons, in the past 10 years, the national laboratories and all the professional filter dust holding capacity makers rarely conducted the tests. Currently JG/T22- 1999 "general use of ventilation air filter performance test method" [2] The industry standard is being revised, the dust holding capacity test is the key element of the amendment. This paper JG/T22- 1999, the United States ANSI/ASHRAE52.1-1992 [3], the European EN779: 2002 [4], Japan JISB9908: 2001 [5] four in the air filter performance test methods more representative dust holding capacity of standard definitions and test methods are introduced and analyzed in order to help States target revision.
National standards introduced in the dust holding capacity
In JG/T22- 1999, the dust holding capacity is defined as: filter by tried to test the termination condition in the block before the total amount of artificial dust, it's made by the artificial dust was tested by the total mass of dust filter average, and efficient computing available; dust holding capacity of the test methods are: dust emission by a certain amount of artificial devices to send to the dust filter installed by the tried and the end filter (generally efficient filters) criteria for testing the wind Road until the man sent after completing dust, remove the filter and tried by the end of the filter were weighed and the change in the quality obtained to calculate the weight by tried to filter efficiency, repeat the above steps until the subjects Filter device to achieve the final resistance value, and then calculated the average throughout the experiment the weight efficiency, the efficiency of the final weight multiplied by the average total fat in the dust be tried by the filter dust holding capacity.
EN779: 2002 definition of cultural cooperation with the quantity of dust and dust holding capacity of the test methods and JG/T22- 1999 were almost identical; ANSI/ASHRAE52.1- 1992 trial only in the dust holding capacity and JG/T22 termination conditions - 1999 is different from other content is the same; and JIS B9908: 2001 In addition to the termination dust holding capacity test conditions and calculation method is not the same, the other also, and JG/T22-1999 similar content. So, dust holding capacity of various standard test method is to test conditions and calculation methods to terminate the existence of some differences. Table 1 lists the dust holding capacity of various standard test conditions and calculation of termination.
Dust holding capacity test for termination conditions
Can be seen from Table 1, the four standard tests in order to achieve the final termination of all resistance to the basis for judging the condition and JG/T22-1999 and EN779: 2002 This is a judgment conditions only, while the ANSI/ASHRAE52 .1 - 1992 and JISB9908: 2001 also reduced the efficiency of using weight to determine the test to terminate or not.
1, to finally end the resistance as the test conditions
For most filters, the resistance is generally instead of falling. This case, it can be used directly to end resistance or dust holding capacity test to determine whether to terminate, at this time, the number of dust holding capacity and the size of the final resistance is closely related to the final resistance test set higher dust holding capacity obtained the greater the value.
End resistance of the two main conditions: 1) 2 times the initial resistance; 2) recommended by the manufacturer. Filters because of their different structures and types, and some initial resistance is low, then 2 times if the initial resistance as the final obstacle for these filters is clearly not fair; if recommended by the manufacturer only to end the resistance, it is possible different manufacturers at the same level of resistance of the filter is not the same end, so that the capacity of the various manufacturers have no comparable dust, which will give consumers the choice filter trouble. Therefore, in order to filter dust holding capacity is more reasonable targets and norms, may be considered the final value of unified resistance, a level corresponding to a filter or a range of end resistance value, the literature 6, through analysis and summary, given a number of recommendations end resistance (Table 2), a good reference.
2, in order to reduce the weight efficiency of the termination conditions as the test
For crude fiber with loose material of low efficiency filters, filter more sparse because, more product of coarse dust particles, filters, resistance to certain value, the dust layer is penetrated and dust off a rebound from the dust layer, the second dust, resulting in filter resistance is not increased but decreased. This case, the trial judge must terminate the terms of the efficiency of using lower weight to determine that the ANSI/ASHRAE52.1-1992 conditions in b) and condition c) or JISB9908: 2001 in terms of b), the JG / T22-1999 and EN779: 2002 there is no provisions in this regard. Obviously, JG/T22- 1999 as a national standard requirement in this regard is not perfect, so the amendment is necessary in a corresponding increase in the content of this field.
Dust holding capacity is calculated Can see from Table 1, JG/T22 - 1999, ASHRAE52.1 - 1992 and EN779: 2002 dust containing the same calculation method, are made of artificial dust total mass of dust filter and tried by the average weight efficiency of product value through the dust holding capacity; JISB9908: 2001 is the filter through direct weighing or by the end tried to derive the filter dust holding capacity.
Under JG/T22- 1999, ASHRAE52.1-1992 and EN779: 2002 standard method such as, dust holding capacity to get the value have to find the average weight efficiency, but efficiency is the average weight for the coarse Evaluation of the filter efficiency rating, which for the efficient and effective filter of little practical significance. The JISB9908: 2001 is calculated on the relatively simple and more intuitive to reflect the filter dust holding capacity. Therefore, the standard revision could be considered JISB9908: 2001 is calculated by the direct weighing test before and after the filter tried the weight of their difference About the Author
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