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Coalescing filters are used to remove fine drops from aerosols and emulsions. Fibrous nonwoven filter media are commonly used to coalesce small drops into larger drops for easier removal. The coalescing performance of a medium is dependent upon several parameters including permeability, porosity, and wettability. In many coalescing filters, glass fibers are used. In this work, we measure the properties of steel fiber media to see how these properties compare to glass fibers in coalescence performance. Steel fiber media have several differences in material properties from glass fiber media that may prove advantageous in performance and filter design. Steel fiber media are more ductile than glass fibers making them more suitable for vibrating environments and easier to machine with reduction of fiber shedding. The steel fiber media are elastic and can be compressed to change media properties such as permeability and porosity. The steel fibers have different wetting properties than glass and may give better coalescing performance for some liquids and they can be applied at higher operating temperatures than glass fibers. Nonwoven stainless steel and glass fiber media with fiber diameters of 2 and 6 μm were used. Permeabilities were measured using a Frazier Permeability Tester, porosities were measured using a custom made pycnometer, and wetting properties were measured with a modified Washburn test. The media performances were evaluated in a coalescence test apparatus. The overall performances of the steel fiber and glass fiber media are compared using a filtration index. 2 μm glass and 6 μm stainless steel fiber media had separation efficiencies of about 85%. Due to the higher permeability of 6 μm stainless steel media, its filtration index was significantly higher.

The performance of gas–liquid coalescing filter media depends on material properties and operating conditions. To optimize the filter performance, highly porous filter media are fabricated with micron-sized fibers with diameters typically in the range of about 5–20 μm. In recent experiments with fiber diameters less than 5 μm the thicknesses of the media were observed to decrease as the amount of liquid held in the media increased. This paper reports on empirical measurements of the shrinkage of the media due to the presence of the liquid drops. This shrinkage phenomenon is attributed to capillary forces compressing the media primarily in the thickness dimension. The shrinkage depends upon the fiber diameter and the wetting properties of the fiber surfaces. The shrinkage caused variations in media properties (pore size, porosity, and permeability) and affected the coalescence performances of the media. The objective of this work was to measure the shrinkage, the effect of the thickness shrinkage on the media properties, and the effect on coalescing filter performance. Experiments were conducted on two media materials (glass fibers and stainless steel fibers) with fiber diameters ranging from 1.5 μm to 22 μm wetted by three organic liquids (Sullube-32, Ultra Low Sulfur Diesel and Viscor 1487) and by water. The results show the shrinkage phenomenon varied with amount of liquid in the media and the fiber material. The effects of shrinkage on the filter properties and coalescence performance were compared to mechanically compressed media to similar thickness. The mechanically compressed media had higher pressure drops but also higher separation efficiencies.

An efficient gold-catalyzed procedure for the preparation of 2-vinylimidazolidinones has been developed. The starting materials for the synthesis of these compounds are α-amino allenamides which undergo heterocyclization by means of nucleophilic attack of the amino group on the inside double bond of the 1,2-diene moiety. This is the first example of a gold-catalyzed cyclization on allene substrates bearing an amido group which, however, resulted inactive.