100 



CHEMICAL MAXUEES. 



or horse heads) than the simple mills. They thus grind fineiv 

 which is an advantage in making gelatine, when it is desired to 

 make as complete an extraction as possible and to obtain gelatine 

 of good quality. The output of these machines is about 1^ tons of 

 crushed bones per hour. 



To grind degreased bones cast-iron stamping mills, fitted with a 

 steel grate in the bottom, and on the longitudinal side with wrought- 

 iron sieves, are used. The fineness of the holes in the grating and in 

 the wrought- iron sieves depends on the fineness of grain desired. 

 Stamping mills are of 1, 2, 3, 4, 6, 8 or 10 stamps of 1 cwt. to 2 

 cwt. ; their yield per hour is about ^ ton of ^ inch bones. 



Disintegrators — Mills luitli Percussion Blades Fitted in Circular 

 Bevolving Boss. — For grinding raw bones, dried meat, and blood. 



Fig. 17.- 



-Disintegrator. 



disintegrators are used with advantage. The mill consists essenti- 

 ally of a framework with vertical grinding cage, in which a bo ss- 

 fitted with blades revolves at great speed. The cage consists of 

 two lateral sides and of a cover of wrought-iron, and a semicyli n- 

 drical grate in two pieces, or completely cylindrical in four piec es. 

 The lateral sides are lined inside with grooved plates of harden ed 

 cast-iron. According to the size of the mill the material to be 

 ground may be in fragments of the size of an egg to that of the fi st. 

 When it is fed through the hopper it is seized by the blades a nd 

 projected against the grinding plate and the steel bars ; it th us. 



