Expression press

Natural Products. Various methods have been and continue to be employed to obtain useful materials from various parts of plants. Essences from plants are obtained by distillation (often with steam), direct expression (pressing), collection of exudates, enfleurage (extraction with fats or oils), and solvent extraction. Solvents used include typical chemical solvents such as alcohols and hydrocarbons. Liquid (supercritical) carbon dioxide has come into commercial use in the 1990s as an extractant to produce perfume materials. The principal forms of natural perfume ingredients are defined as follows the methods used to prepare them are described in somewhat general terms because they vary for each product and suppHer. This is a part of the industry that is governed as much by art as by science. 

In the past, expression presses were used in many processes for extracting oil and juice, generally from seeds and fruits such as olives. Batch presses were typically used in these apphcations, and hand unloading of the pressed cake was often required. Batch presses that require hand unloading or extensive cleaning between pressings are rarely used now descriptions of various types are presented in earlier editions of this handbook. This section, therefore, describes mainly continuous presses. 

Press-, pressed, compressed, expressed, pressing, press glazed, -aitikel, m. (Rubber) press-cured article (s). pressbar, a. pressable. 

The equipment used for dewatering includes filters and screening devices of various types, centrifuges, hydrocyclones, extrusion and expression presses, water extractors, and thickening, clarifying, and flotation hardware. The processing methods encompass a broad range of water-removal techniques. They... 

Figure 1.38 Schematic representation of a typical expression press.

To reset the equations back to the default expression, press the Reset button. 

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