Currently , both baghouse equipment manufacturers or direct users in the selection of filter you will filter manufacturers claim to provide specific technical filter parameters . The technical parameters required , often the emphasis on : ( 1 ) filter weight ( mass per unit area ) . Since the filter is textile products , the measured value and the nominal value of certain deviations . In accordance with national standards, the mass per unit area of needle felt filter , allows a deviation of +/- 5% . But some users , for prevention purposes .Filter vendors often cut corners to filter bag manufacturers presented as the weight must be greater than 550 g / m² and other requirements . If the filter manufacturers in response to requests made a commitment , it means that the filter media must be controlled in the production of g lies 580g / m² , that is, the nominal value of the filter is 580 grams instead of 550 grams should no longer be . ( 2 ) filter thickness or density ; GB in thickness of the filter also allows for a deviation of +/- 10% . ( 3 ) filter media permeability ; Note: The filter density and permeability are related . Acupuncture quality equipment and technology is to ensure that high-quality media production premise. If the filter is not enough dense, permeability may well filtration efficiency of the filter and ash removal performance will be degraded. ( 4 ) strength and elongation of the filter ; (5)filter temperature resistance (allowable temperature continuous operation and can withstand instantaneous operating temperature). As filter manufacturers, the user must have a responsibility to raise the expectations of the filter bag life (such as 30,000 operating hours or 45 months, etc.), based on the fibrous material of temperature and chemical resistant (resistance to oxidation and hydrolysis) feature, integrated presentation selected filter allows maximum continuous operating temperature and maximum instantaneous operating temperature. If the actual flue gas temperature often exceeds the filter maximum permissible continuous operating temperature, then the user must consider: system on or take measures to improve the system equipment such as air pre-heater heat exchange efficiency and reduce exhaust gas temperature; or reduce bag expected life requirements (as well give up 30,000 operating hours requirement). Filter made of a maximum instantaneous operating temperature is reasonable, because the system does occur transient over-temperature (over-temperature means: exceeds maximum continuous operating temperature). Here we must also note two points: First, the filter allows maximum instantaneous operating temperature is not exceeded; the second is over-temperature instantaneous, have agreed on a time, usually a few minutes to allow over-temperature requirements for each year the total time-temperature can not exceed the number of hours and so on. (6) filter thermal shrinkage. Since most chemical fiber filter manufactured, under certain conditions the filter temperature will heat shrinkage occurs, the media production must be heat set. Heat-setting process is critical, and often filter manufacturer for technical secrecy. At home and abroad we have all (bag cage at the top of the case there is no fixed) due to thermal contraction caused by the filter bag the top of the flower board occurred or bursting dust at the bottom of the bag case. However, the bag especially as 8 to 9 meters long filter bags, hanging behind the flower will have a board filled with dust weight plus gravity force drawn down from the bag, so the filter and heat shrinkage elongation factors also need to consider the balance. Excessive heat setting, or excessive demands of small thermal shrinkage, can also cause the bag during use of elongation, and thus will shorten the actual life of the filter bag. In fact, the choice of filter elements or functional performance, not just those mentioned above filter durability (or expected life, etc.), quality and technical requirements.