TREATMESr FOR TEXTILE IXSTLATIOX 



239 



It was found that the \iscosil\' of the solution had to be maintahied 

 within close limits, as the weight of iilm left on the wire changes with 

 the viscosity. To continuously indicate the viscosity, a constant 

 amount of solution is pumped through an orifice and the back pressure 

 developed is measured by a pressure gauge, the gauge being calibrated 

 for viscosity-. Deviations from the required viscosity are corrected 

 In- the addition of acetone or a more concentrated solution that is kept 

 in readiness. 



MIXERS 



Fig. 8 — .Schematic of the wire treating plant at the Kearny, Xew Jersey works of 

 the Western Electric Compan^•. 



To keep the amount of acetone solvent low for the required vis- 

 cosity, the temperature of the solution is kept at about 86° F. Al- 

 though a higher temperature would require the use of even less solvent, 

 it would increase the loss by evaporation. To maintain the desired 

 temperature, a water coil was installed in the mixer, the water in turn 

 being heated by steam. This indirect method was used instead of 

 installing steam coils directly in the mixer as the latter would result 

 in boiling the cellulose acetate solution and the coils would become 

 heavily coated with cellulose acetate. The mixers are equipped with 

 standard propeller type agitators driven through gear reduction by 

 totally enclosed motors. 



During the drying operation the acetone is evaporated giving a 

 mixture of air and acetone vapors within the drying chambers. This 

 mixture would be explosi^•e if the concentration of acetone vapors were 



