BULLETIlSr 681, U. S. DEPARTMENT OF* AGRICULTURE. 



the left disk in position, and acts as a safety appliance to allow the 

 disks to separate in case hard substances pass through the mill. 

 L is a quick-release lever for operating the spreading device. 



Figure 2 is a diagrammatic view of the removable hopper (h) 



under the mill, spout 

 ~A (s), single revolving 



damper (installed for 

 Series 8 and 9), and 

 screw conveyor. The 

 by-pass spout with its 

 valve and peephole 

 (C) was installed for 

 the purpose of observ- 

 ing how far the flame 

 /-\ r\ .-^A — Y\ r\ r\ i\ due to an explosion 



^^Z^t^•^f~-r-''•^"~-"t'--fcf— ^-~-tV:V-^^ iT^ay be propagated 



V/' \J \J '"■'-'' \J \J ''J /V without the use of a 



/P'O RPM. 



Sca/e 



l-Foof 



Fig. 2. — Elevation-attrition mill and conveyor. 

 Single damper. 



"check" valve. B is 

 a peephole for observ- 

 ing any flames that 

 may pass the damper. 

 The construction of the single damper can be seen in figure 3, 

 which gives the arrangement when two of these single dampers were 



=] 





















m m 

















LU LU 















D 



Fig. 3. — Views of double damper. 



placed in series, as in Series 11. As can be seen in the sectional view, 

 the paddles or blades with their rubber "wipers," shown in black, 

 are so arranged that there is never a clear path tlirough the damper. 



