STOEING OF SUPEKPHOSPHATE. 115 



blades r. The other arm _/:>, conveniently fixed behind the first, is 

 fitted at its free end with a sort of shovel or spoon s. A con- 

 veyor t, of known construction, is arranged below the opening c of 

 the den and empties into a suitable elevator u. A band of stuff v, 

 fitted with suitable counterpoises x and ij, is arranged above the 

 screw shaft i, so as to cover it when it enters inside the den. A 

 mixer z is fixed at the top of the " den," and the installation may be 

 completed with fans and condensers of any desired construction. 

 The cog-wheel h may be driven by any suitable means, for example 

 by a play of pulleys fixed and movable, 1 and 2 acting in different 

 directions. The working is as follows : During the mixing of the 

 mass of superphosphate the trap door d covers the opening c and 

 the door g covers the circular opening in the front of the " den," the 

 two arms, o and_/;, being kept outside the " den ". After the super- 

 phosphate has set, the trap door d is withdrawn by aid of a hand- 

 winch, not shown on the drawings, then the door g is removed. 

 The whole of the shafts, h and i, are caused to revolve in a suitable 

 direction to bringthe mechanism inside the " den ". When the teeth 

 q of the arms o come in contact with the mass of superphosphate, it 

 penetrates into the interior of the mass, detaching ribbons which 

 lireak, forming small fragments, which fall to the bottom of " den ". 

 The blades r in turn come in contact with the portion of the matter 

 projecting between the teeth, detach these likewise in the form of 

 ribbons, which collect at the bottom of the " den ". The shovel s at 

 the aperture C brings these fragments, from where they fall into the 

 conveyor t. Whilst the shaft i is penetrating inside the "den," the 

 .cloth V unrolls and covers this shaft so as to prevent it being crushed 

 by lumps of superphosphate. When all the matter in the " den " has 

 been reduced to fragments and evacuated by the conveyor the rota- 

 tion of the shafts h and i are reversed, until the arms o, jj are outside 

 the "den " ; the sliding door d is replaced as well as the door g, and 

 the mixing of a fresh batch started. This arrangement is simple and 

 •economical. The arms supporting the cutting knife is fixed on a 

 shaft supported at both ends, which prevents all work in false direc- 

 tions and secures a better output. The attack of the material by 

 a vertical knife facilitates the conveyance of the fragments it turns 

 out. This arrangement may be applied to all existing "dens " by 

 modifying or not the inside shape of these "dens," so as to render 

 them cylindrical. During the mixing of the superphosphate no 

 •delicate piece of the mechanism comes in contact with the material, 

 so that the mechanism is practically unwearable and little liable to 

 damage. The screw shaft may be replaced by any other arrange- 

 ment giving to the arms o, _/9 a forward helicoidal motion, and 

 fitting the whole mechanism with an arrangement allowing the 

 speed of the displacement of the arms to be increased at will ; 

 for example, for their return. The invention applies to the 



