FILTRATION 



303 



and is similar to the juice plate except that the transverse openings w com- 

 municate by a channel, b, with the interior of the press. Between the 

 plates and the frames are stretched the filter-cloths ; and both sides of the 

 plates are ribbed or channelled or formed with a system of pyramids on 

 their surface, to afford rapid drainage of the liquid that passes through 

 the cloths. 



On both juice and water plates are located cocks communicating with 

 the interior of the press by the channels c. The stems of these cocks may 

 be of unequal height, so that one cock may be closed while the adjacent 

 ones are open, or the flap closure shown in Figs. 174 and 176 may be used. The 

 assembled press is shown in Fig. 177, piping connections being omitted. 

 The press is set up in the order : filter head, frame, juice plate, frame, 

 water plate, frame, juice plate, etc. The frames are indicated by two dots, 

 the juice plates by three dots, and the water plates by one dot. 



Dirty juice is admitted under pressure to the openings j (see Figs. 174, 

 175 and 176), and passes into the frames by the channels a. The cloths 

 catch the suspended matter, and the clear filtrate which passes through the 

 cloth runs out by the channels c and the cocks e into the gutter /, Fig. 177. 



FIG. 177 



When the frames are filled with the intercepted matter washing begins. 

 Water is admitted to the conduit formed by the transverse openings w, and 

 at the same time the cocks on the water plates are closed. In order to escape, 

 the water has to pass through the wall of cake and out through the cock 

 on the juice plate. The plates are pressed together by means of the gear h, 

 and in some designs hydraulic closure is used. Rubber rings inserted in the 

 transverse openings make a tight joint, and these may be replaced by cloth 

 pockets, in which are cut holes registering with the openings in the lugs. 

 The gutter which receives the juice should be provided with three exits, 

 one each for dirty juice, clear juice and washings. 



In the plate chamber press the chamber is formed in the space confined 

 by the juxtaposition of two plates. The plates are made with thickened 

 edges, the thickness of the edge determining the thickness of the cake. 

 The form peculiarly associated with the Dehne press is shown in Figs. 178 

 and 180, which represent respectively the water plate and the juice plate. 

 Fig. 179 shows six plates as assembled in a press, the odd-numbered plates 

 being the water plates. The dirty juice conduit is central to the plates, 



