Plastic coated metal meshes

A wide variety of screens and meshes are available, ranging from fine photoetched or electroformed perforated screens to the heavy duty wedge wire screens used in centrifuge and high pressure screw press construction. Simple sieves and coarse screens were used as early as the sixteenth century for processing metal ores. Modern woven wire screens are precision made cloths with aperture sizes as small as 20 pm (smaller aperture sizes are supplied by some manufacturers) for industrial separations in filtration, clarification and extraction. Plastic meshes and plastic coated metal meshes are finding an increasing number of applications in separation processes. 

This is a process in which ink is pushed through a screen comprising a fine mesh of plastic or metal fibers (Fig. 12.IE). The pattern is defined by filling certain openings of the mesh with a stencil material. The screen is coated with the ink, and us-... 

ASTM C285-88 (Re-approved 1994) Standard test method for sieve analysis of wet milled and dry milled porcelain enamel, for determination of the fineness of frit in wet-or dry-milled porcelain enamels and other ceramic coatings on metals by use of the number 200 or No 325 mesh, 212 ASTM C925-79 (Re-approved 1995) Standard test method for precision electroformed wet sieve analysis of non-plastic ceramic powders, for particle size distribution determination ofpulverized alumina and quartz for particle sizes from 45 pm to 5 pm by wet sieving, 212, 230... 

Pd-Cu alloy coated plastic samples were first cut into discs 75 mm in diameter, sandwiched together with a porous metal disc (Monel) between two microscreens and then clamped (refer to schematic in Fig. 11.2). To remove the plastic backing material, the samples are then lowered horizontally with the coated polymer discs up. Monel mesh down, into the appropriate solvent hot water (60-80°C) for Solublon and chloroform (room temperature) for polystyrene. Polymer dissolution (removal rate) was evaluated as a function of temperature and time. Nominal times were 30 s for the Solublon and 600 s for the polystyrene. Upon dissolution of the polymer backing material, samples were removed from the solvent, carefully disassembled and then dried. 

One of the most successful commercial anodes is the expanded titanium mesh with an activated precious or mixed metal oxide coating. This also comes in the form of an expanded titanium mesh, strips and other configurations. It is fixed onto the surface, usually with plastic fixings and a cementitious overlay applied. 

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