400 



CHAPTER XIX 



Short Coil Pans. — A disadvantage of the type of pan described above 

 is the great length necessary for the coils as the size of the pan increases. 

 This results in a very inefficient heating surface, and to avoid this difficulty 

 various types of coil pans which abandon the helix are made. Three of 

 these arrangements of coils are shown in plan in Figs. 241 to 243. In Fig. 

 241 is indicated the lyre coil device. Vickess' patent (15773 of 1892), one 

 of the earliest types, is seen in Fig. 242, that of Lorenz appearing in Fig. 243. 



Fig. 247 



In all these combinations the coils are collected at one extremity in a steam 

 chest, and at the other is a collector box for the condensed water, and in all 

 arrangements the maximum travel of the steam is very much less than that 

 in the standard coil pan. 



In all these devices it is customary to arrange the horizontal coils in nests 

 of three or four, which pass into a common collector box and amongst them- 

 selves for a heating element. This scheme is indicated in vertical section 

 as for the lyre pan in Fig. 244. 



