THE EVAPORATION OF THE JUICE TO SYRUP. 



from vessel to vessel and finally to the condenser of the pump. The pipe 

 collecting the gases should be placed as remote as possible from the steam or 

 vapour inlet ; it is quite usual to find the gases collected in three or four 

 places, the several pipes afterwards uniting into one. The pipes collecting 

 the gases should be arranged flush with the top tube plate, and should not 

 project beneath it, else opportunity will be given for the gases to accumulate. 



Condensed Water. The condensed water from the first vessel is 

 used in the boilers, and there being a pressure in the calandria of the first 

 vessel it does not require to be drawn off by a pump, but may be passed 

 through a steam trap. The condensed water from the second and subsequent 

 vessels must be drawn off by a pump, and its rapid evacuation has a con- 

 siderable elfect on the efficiency of the apparatus. This water is not suitable 

 for use in boilers, and is generally employed in maceration. A small heat 



FIG. 173. 



economy is obtained by passing the condensed water of the second vessel 

 through the calandrias of the third and subsequent vessels. In certain 

 instances a pump for drawing off the condensed water is dispensed with, the 

 water being trapped and passed into the main pump ; this scheme is not to be 

 recommended, both on account of diminishing the efficiency of the pump, and 

 also as losing a valuable supply of hot water. 



Distribution of Steam in the Calandria. The earlier types 

 of apparatus were provided with only one pipe for carrying steam to the 

 calandria, resulting in an uneven distribution of steam ; the later apparatuses- 

 distribute the steam by any of the following devices : 



(a) The arrangement of baffles in the calandria causing the steam to 

 follow a zig-zag course ; these baffles may be horizontal or vertical ; in one 

 design a baffle following a helical course is used, the steam entering at the side 

 and being conducted to the centre of the vessel. 



303 



