Fiberglass filtering material

The principles behind ultrafiltration are sometimes misunderstood. The nomenclature implies that separations are the result of physical trapping of the particles and molecules by the filter. With polycarbonate and fiberglass filters, separations are made primarily on the basis of physical size. Other filters (cellulose nitrate, polyvinylidene fluoride, and to a lesser extent cellulose acetate) trap particles that cannot pass through the pores, but also retain macromolecules by adsorption. In particular, these materials have protein and nucleic acid binding properties. Each type of membrane displays a different affinity for various molecules. For protein, the relative binding affinity is polyvinylidene fluoride > cellulose nitrate > cellulose acetate. We can expect to see many applications of the affinity membranes in the future as the various membrane surface chemistries are altered and made more specific. Some applications are described in the following pages. 

Depth filters consist of an array of fibers oriented randomly, and the filters retain particles inside the filter material. Depth filters are constructed of materials such as cotton, fiberglass, sintered metals, and diatomaceous earth. Insoluble or colloidal particles are removed from the fluid by attraction and capture or adsorption to the filter matrix. Particles of 0.01 pm can be retained by these filters. Frequently, materials of various stages are combined in one filter, where the feed comes into contact with the matrix initially more open. Depth filters are operated in perpendicular mode [6]. 

Fibrous bed coalescers generally have a fixed filter element constructed of fiberglass or other material that acts to coalesce (bring together) the oil droplets and to break emulsions. The coalesced oil droplets released from the filter are readily separated downstream by gravity. Coalescence in a fibrous bed coalescer involves three steps ... 

For the preparation of the peanut skin tannin, the red skins were separated from residual nut and hull material by hand sorting, and then about 30 lb of skins were extracted with acetone-water (60 40 v/v) at a liquor-to-skins ratio of 5 to 1 at 50 °C for 4 hr in a stainless steel tank. The extract was filtered through a fiberglass mat, the acetone was removed under vacuum on a rotary evaporator, and the aqueous solution was freeze-dried. 

Test vessel type and size Adults large aquarium or fiberglass or stainless steel raceways side of tank should be opaque and at least 30 cm high Breeding Adults 5- or 10-gal aquarium fitted with a 1-cm mesh suspended approximately 3 cm from the bottom of the tank nylon or plastic mesh is recommended aquarium should be fitted with a bubbler to oxygenate the water the top of aquarium should be covered with an opaque porous material such as a fiberglass furnace filter Embryos 60-mm glass or 55-mm disposable polystyrene Petri dishes... 

Materials for the lateral flow strips including membranes, fiberglass, and filter paper are commercially available from several manufactures, such as Millipore Corp., Schleicher Schuell (S S, Keene, NH), Whatman, Inc. (Clifton, NJ), and Pall Biosciences (East Hills, NY) etc. 

Fabric Filters. Fabric filters collect solid particles by passing gas through cloth bags that most particles cannot penetrate. As the layer of collected material builds on the fabric, the pressure differential required for continued gas flow increases consequently, the accumulated dust must be removed at frequent intervals. Fabric used to form the filter elements can range from nylon to wool to Teflon-coated fiberglass, shaped into cylindrical bags or envelopes with a roughly elliptical cross section. 

In this section (6.6) we will describe manufacture of the continuous and discontinuous fiber used for textiles, reinforcement, insulation, and filter media. All of these materials are often referred to by the one word fiberglass. This section also discusses traditional (noncommunication) fiber optics. Optical communications fiber is discussed in Sec. 6.7. 

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