350 



CHAPTER XVIII 



in which the cells are superimposed one on another. This design appears 

 in Pecqueur's French patent (6686, 1834), and in a number of recent designs. 



Horizontal Submerged Tube Apparatus. — ^The original RilUeux multiple 

 effect was of this type, and for its historical interest one cell is shown in 

 Fig. 195 ; some very early apparatus of this type still (1919) remain in 

 operation in Cuba. The modern form is contained in the Welner-Jelinek 

 design used very extensively in Germany, Austria and Russia, and in the 

 derived forms of the Swenson and Newall in the beet sugar industry of the 

 United States. The Welner-Jelinek apparatus is illustrated in end elevation 

 and in longitudinal section in Figs. 196 and 197. The tubes forming the 

 heating surface may be as much as twelve feet long and from three quarters 

 to an inch and a quarter in diameter ; they are supported in tube plates 

 at either end, and in intermediate plates shown at j, and are arranged in 

 nests of nine or twelve. The steam enters the steam chest through the 

 valves / and g, one being used for live and one for low pressure steam. The 

 tubes are set at a slight incline to assist the flow of the condensed water 

 to the collecting box at the opposite end to the steam entry whence it is 

 removed through the valve h. The incondensible 

 gases are vented through the opening i. Internal 

 baffles cause the juice which enters at m to make 

 several changes of direction before it reaches the 

 exit shown to the right of the steam valve g. An 

 entrainment vessel communicating with the vapour 

 space by the conduits c forms part of the usual 

 design. The advantage originally insisted on in 

 this type was the obtaining of a low level of the 

 material being evaporated, and, in order to maintain 

 this advantage without increasing the size of the 

 shell, apparatus are built with two heating elements 

 in one chamber, as indicated in Fig. 198. 



In contradistinction to the vertical submerged 



tube type, the heating surface of this apparatus 



cannot be cleaned mechanically in situ. 



Yaryan Evaporator. — ^This evaporator is included in patents 14162, 



1886; and 213, 1888 : U.S. patents 300185, 1884 ; 355289, 355290, 1886 ; 



and 383384, 1888. 



In this evaporator the juice occupies the interior of tubes arranged 

 horizontally, through which it is pumped at a high velocity. As shown in 

 Fig. 199, steam enters the shell at e, and juice entering at d passes through 

 the tubes, leaving at g. The juice does not fill the tubes, but forms a film 

 on the inner periphery. On arrival at the end of a run, juice and vapour 

 pass through j to the separator h, seen in section in Fig. 200. The vapour 

 passes up and down the baffle plates h, and thence by the pipe k to the next 

 effect or to the condenser. The liquor passes through the pipe i to the tubes 

 of the next effect. 



This apparatus may be built with the vessels in either the same vertical 

 or horizontal plane ; it is now only exceptionally found in the cane sugar 

 industry. 



Lillie Evaporator. — This evaporator is contained in patents 3006, 12391, 

 of 1888 ; 11686, 1890 ; 7187, 1891 ; 11104, 1893 ; U.S. patents 341669, 

 344586, 1886 ; 378843, 1888 ; 422234, 422235, 440231, 1890 ; 466862, 



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