Dewatering hydraulic press

Presses are of two basic types hydraulic batch presses and screw presses. Hydraulic presses are used for extracting fruit juices, and screw presses for dewatering materials such as paper pulp, rubbish and manure. The equipment used is described in the handbooks Perry et al. (1997). 

The Mini-Miser dewatering system uses hydraulic pressure to mechanically extract liquids from sludges, sediment, and solids. The system incorporates a patented press design that has previously... 

The vertical filter press, like the horizontal press, is strictly speaking a batch operating filter, but is more correctly called a semi-continuous filter, because the cake is discharged from all of the compartments at the same time. When the filtration cycle starts, the plate assembly (Figure 3.73) closes, and slurry is fed to all of the compartments at the same time. Cakes form on top of the filter medium in each compartment. Once filtration is complete, diaphragms are forced hydraulically down on the cakes to dewater them. Then the diaphragms are relaxed, wash water is introduced, and the cakes squeezed once again, followed by a compressed air blast to dry them further. At this point, the plate assanbly opens, and the continuous band of filter medium advances... 

Once the maximum feed pressure has been reached, depending on the nature of the feed pump, then the feed system is closed and the tube press is isolated. Hydraulic fluid is now introduced between the elastomeric sleeve and the pressure vessel outside it, so as to squeeze the filter cake by meaus of the flexible sleeve. Squeezing pressures up to 140 bar are used, to dewater the filter cake, often to a degree of dryness where further thermal drying is unnecessary. The sleeve is then sncked off the cake by vacuum, and the inner tube is lowered free of its housing, and a pnlse of compressed air cracks the cake, which falls off the candle into a receiving vessel below it. 

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