Particle Size and Distribution Air / Fluid Filter - Filtration

Filtration Table of Contents

Distribution of Particle, the chart given below, shows the distribution of particles (by weight percent) in atmospheric air as a function of particle shape. Variations in particle shape, mean particle size, particle size range, and concentration affect filter life, maintenance costs, and operational effectiveness. The size range of various types of particles, the technical nomenclature of various types of aerosols, and the applicability of various types of air cleaning devices as a function of particle size are shown below . A major source of the lint often found on filters is derived from the abrasion of clothing as people move about. In addition, a person at rest gives off more than 2.5 million particles (skin, hair, etc.) and moisture droplets/minute in the size range of 0.3 to 1 m.3 Process-generated aerosols fall into two general size ranges. Those produced by machining, grinding, polishing, and other mechanical operations are generally large, (from 1 to several hundred m), according to the nature of the process, and can be removed effectively by common air filters or other conventional air cleaning techniques. The other size range includes those produced by evaporation/condensation and other chemical operations, which generate droplets and solid particles that are often sub micrometer-sized. These aerosols are more difficult to separate from air or gases, requiring collectors such as HEPA Air filters. Ultra Low Penetration Air (ULPA) filters provide a higher cleaning efficiency (up to 99.9999 percent for sub-micrometer particles). [Note: A need for this level of efficiency is rare for industrial applications. The media used in ULPA filters is weaker than that used in HEPA Air filters, a factor that must be considered for any application of ULPA filters to air cleaning system or other applications where durability and reliability are concerns.]

Characteristics of atmospheric and process-generated particulates, fumes, and mists and effective range of air cleaning equipment.

Click on image below to enlarge

Partical Diameter Chart