![]() ![]() The NA quoted for Abbé condensers is frequently as high as 1.20 but, due to the lack of correction, the iris diaphragm must be partly closed in order to produce an aplanatic cone of light. For critical work, an achromatic condenser which consists of a series of lenses is essential. This can be reduced by partly closing the iris diaphragm, or by placing immersion oil on the top lens of the condenser, under the object slide. As no correction is made for chromatic or spherical aberration, a considerable amount of scattering occurs. It consists of two lenses and an iris diaphragm. The most common type is the Abbé condenser, designed by Professor Abbé in 1872. SILVERTON F.I.M.L.S., L.I.Biol., in Introduction to Medical Laboratory Technology (Fifth Edition), 1976 Bright-field condensersĬondensers under this heading are used with transmitted light for routine work. In particular, condensation is more amenable to fundamental analysis, and useful heat-transfer correlations can be derived from first principles. On the other hand, condensing and boiling differ in important respects. Mass-transfer effects may also be significant in the condensation of mixtures, as they are in nucleate boiling of mixtures. For wide-boiling mixtures, in particular, the nonlinearity of the condensing curve and the variation of liquid and vapor properties over the condensing range mean that a zone or incremental analysis is required for rigorous calculations. Thus, many of the computational difficulties encountered in the analysis of reboilers are present in condensers as well. ![]() Heat exchangers referred to as surface condensers are used to condense the exhaust from steam turbines that generate in-house power for plant operations.Ĭondensation is the reverse of boiling, and the condensing curve is the same as the boiling curve. In refrigeration operations, condensers are used to liquefy the high-pressure refrigerant vapor leaving the compressor. Virtually, every distillation column employs either a partial or total condenser to liquefy some, or all, of the overhead vapor stream, thereby providing reflux for the column and (often) a liquid product stream. Serth, in Process Heat Transfer, 2007 11.1 IntroductionĬondensers are used in a variety of operations in chemical and petroleum processing, including distillation, refrigeration, and power generation. ![]()
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