5.
How can air filter effects on overall system pressure drop be predicted? Thermal analysis software is available for thermal / mechanical designers to simulate and predict cooling requirements. The thermal software packages, configured with component thermal libraries, enable users to predict pressure drop through air filter elements quickly and accurately. Universal Air Filter has provided filtration performance data to thermal analysis software suppliers, including Flotherm, Icepak, Macroflow and Coolit, so that filter thermal libraries could be incorporated in their software. Thermal libraries can now be used early in the design process to enhance the accuracy of the thermal analysis.
The trend towards smaller chassis and higher wattage has increased the demand for more data. Thermal modeling software packages are capable of factoring in the effect an air filter has on system pressure drop. Upon request, Universal can provide filter pressure drop and filtration performance data.
Air filter initial resistance and dust loading data can be a valuable resource in determining air filter performance and reliability. It can be to the OEM designer's advantage to specify Universal air filters to satisfy a broad range of electronics and industrial applications.
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6. What is the shelf life of foam and what is the recommended method of storage?
Since air filter foam can be subjected to a variety of environments beyond our control, Universal does not publish a life expectancy. "Shelf life" is not typically used to describe longevity because it is a relative term.
The ideal storage condition for polyurethane foam is a cool, dry, dark environment. Conditions that adversely affect the media are high temperature, humidity, and ultraviolet light. Foam media also degrades when exposed to solvents and sulfates, such as engine exhaust. Reduced foam life depends upon the degree of difference from the ideal conditions the foam is stored.
Customer feedback indicates that controlling relative humidity between 40%-80% and temperature between 40F-90F yields an acceptable environment. Covering the filters with dark plastic will keep media dry and protected from ultraviolet light.
We do not recommend storing foam filters for several months or years at a time. Instead, purchase cost-effective quantities and keep adequate inventory for no more than a few months.
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7. How often should air filters be cleaned or replaced?
Filter maintenance intervals are application specific and depend on the type of equipment they are used in and the environmental conditions the equipment is subjected to. Some equipment design engineers add messages to the controlling software of their device displays to indicate when filters should be serviced based on hours of operation. Others include pressure and / or temperature sensors downstream of the filter to detect when the filter is fully loaded and needs attention. It is accepted throughout the industry for electronics equipment designers to recommend cleaning or replacing air filters approximately every 90 days.
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8. Does Universal make HEPA or other high efficiency air filters?
Universal makes washable pre-filters for HEPA and cleanroom systems. Filters are designed to extend the life of the more expensive, throw-away HEPA filters.
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9. What are framed air filter assembly and pad air filter manufacturing tolerances?
Framed Filters +/-.06" length & width, +/-.03" thickness
Pad Filters +/-.12" length & width, +/-.06" thickness
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