Metal Finishing Guide Book

2012-2013

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Fig. 2. Totally enclosed vapor degreaser can meet stringent environmental regulations. boiling temperature of the solvent): This promotes more thorough drying of the work before it is removed from the degreaser. ��� Carbon adsorption equipment in the ventilation system connected with the degreaser. In addition vapor degreasing operators must employ an automated hoist or conveyor that carries parts at a controlled speed of 11 fpm or less through the complete cleaning cycle. Each of these procedures used alone will reduce solvent loss by a respectable amount while combining two or three procedures reduces loss even further. For example creating a freeboard ratio of 1.0 in an open-top degreaser will reduce loss by 30 to 40% over the traditional process. Combining an increased freeboard ratio with superheated vapor or reduced room draft increases the control level to 60%. And in most cases, if a user combines three of the procedures, this will bring the control up to 70%. Table III illustrates how these incremental improvements can be brought about. Many companies have found it cost effective to adopt one of the new degreasers, which have no air/vapor interface. These sealed and virtually emissionless units were first introduced in Europe to meet the stringent environmental regulations of some countries (see Fig. 2). Typically these degreasers perform the cleaning operation in a sealed chamber into which solvent is introduced after the chamber in closed. Solvent vapor 110

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