60 



possible. There is a groove on each surface at the bottom which con- 

 nects with an opening leading to the outside of the plate into which a 

 small brass faucet is fitted for discharging the juice. The frames consist 

 of an iron rim entirely open in the center. Both the plates and frames 

 are fitted with openings at the top either in the center or at the sides. 

 The more improved types have a series of openings at one side through 

 which the juice is pumped and on the other through which steam or hot 

 water is forced. It is fitted with a fixed plate at one end carrying water 

 and steam connections and at the other with a very strong screw for 

 holding the plates and frame in position when in use. The filter press 

 is prepared for service by having a filter cloth folded in the center and 

 placed over each frame, after which they are shoved together and the 

 head plate connected with the screw is firmly pressed against them. 

 The turbid juice with its mud and scum from the settling tanks is then 

 pumped into the juice connection of the filter press and emerges through 

 openings from the juice passage into each of the frames. The juice is 

 forced by pressure through the filter cloth, trickles down the grooves in 

 the plates and catches in a small gutter at the bottom and runs out 

 through the faucet into the juice trough arranged along the side of the 

 filter press. After the pumps have run sufficiently long the pressure 

 runs up high enough to indicate that the frames are filled with the mud 

 which constitutes the sediment deposited in the tanks. This is known 

 as the press cake and often contains 5 to 6 per cent of sugar, the recovery 

 of which is worth considerable expense on account of the great weight 

 of the press cake from the large mills. This is accomplished by turning 

 on steam or hot water through the opening in the opposite side of the 

 press and forcing it through the press cake for some moments so as to 

 dissolve out most of the sugar which it contains. The steam and juice 

 are then turned off, the press opened up, the cakes dumped out for removal 

 as a waste product and the filter cloths sent to the laundry. The filter 

 press is again ready for work as soon as cleaned and refitted with clean 

 filter cloths as before. 



The sugar makers of the Philippines operating small mills find it very 

 difficult to recover sugar from the scum and sediment although some of 

 them claim that 10 per cent of the total sugar made can be recovered 

 from this source, if sediments and scums are carefully worked, 



CaTce mill. — Large mills using irrigation water for the removal of the 

 cake from the factory usually put in some form of burr-mill for the 

 purpose of grinding the press cake so that it is readily washed away by 

 the stream of water into which it is discharged. This machine is not 

 necessary in mills using cart or rail transportation for the cake, which 

 is generally dumped from the press directly into the vehicle or hopper 

 from which it is subsequently loaded on to cars. 



