RETTING 119 



Fig. 69 is a plan of the retting vat. 



Fig. 70, a longitudinal section through X X. 



Fig. 71, a transverse section through Y Y. 



Fig. 72, a front elevation of the retting section. 



The same letters in each diagram refer to corresponding 

 parts. 



A is a reservoir of any convenient shape and size ; it is 

 combined with a heating apparatus, B, and a second and warm 

 water reservoir, C, preferably placed immediately above the 

 retting vats, D, of which the concrete walls are shown at E. 

 Reinforced girders, F, support the warm water tank, C. A 

 pipe, G, communicates with the tank, C, and supplies water to 

 a conduit, H, consisting of an upper and smaller diameter 

 pipe and a lower and larger diameter pipe, both of which are 

 tapped and provided with oblique orifices. The function of 

 the small pipe is to continuously discharge a fresh supply of 

 warm water during the whole process of retting, while the large 

 pipe is only used at a later period when the retting fermentation 

 is more advanced, and when the foreign substance to be 

 removed has increased considerably in mass and thereby 

 involved a larger displacement of the retting water. The 

 flax straw, I, is placed between the bottom grate, J, and the 

 upper grate, K, in the vat, D. The initial supply is suitably fed 

 from the warm water tank, C, by suitable and convenient sized 

 pipes. The desired temperature is maintained by the supply 

 of fresh warm water through the oblique orifices of one or 

 both pipes in the conduit, H. This water, being warmer than 

 that in the retting vat, naturally rises and rapidly circulates 

 with the greater mass, while the heavier and polluted solutions 

 sink to the bottom, through grid J into the division L from 

 whence it is drawn off by pipes M, which communicate with 

 pipes N and in turn, connected with a trough, P. The 

 trough, P, then overflows and the contents are emptied through 

 a pipe, Q, and either allowed to run to waste or directed into 

 another vat or section to start the preliminary operation of 

 retting again. 



