Expression press continuous type

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. 

Expression Dewaterings of Fibrous Materials. Fibrous materials are frequently dewatered in belt-filter, screw, disk, and roU presses and in batch pot and cage presses. Table 1 Hsts appHcations of screw, roU, and pot presses. Screw and high pressure belt presses are continuous and have replaced batch pot and cage presses in most appHcations. Traditionally, however, batch presses have been used for squee2ing cocoa butter from cocoa beans, which require pressures up to 41 MPa (6000 psi) (39). A description of many types of batch presses is included in Reference 40. 

Furukawa et al. [12] have investigated the piezoelectric properties in composite systems of polymers and PZT ceramics. In prevtous papers (13,14), these authors have described the piezoelectric properties of the composite epoxy rcsin/PZT ceramic system on the basis of the theoretical expressions of the piezoelectric constants for a two-phase system where piezoelectric spherical particles are dispersed in nonpiezoelectric continuous media (0-3 type composite). Also, piezoelectric properties have been studied [12] for composite systems of PZT ceramics and polymers including prdy(vinylidene fluoride) (PVDF), polyethylene (PE), and polyvinyl alcobol (PVA). The composites were prepared in the following ways. PVDF pellets and PZT ceramic powders were mixed al 200XT using a hot roller and then pressed into about a 200-pim-thick film al 180 C. The composite of PE and PZT was made in a similar way. The composite of PVA and PZT was cast from water to obtain a thin film. 

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