METHOD OF MANUFACTURING BBIOK 



167 



Stiff mud process 



This is so called from the fact that the clay is molded quite stiff, 

 being forced from the machine in the form of a hard bar which 

 is cut up into brick. 



The clay is sometimes prepared in pug mills which have been 

 previously described, but pan crushers are mostly used fot this 

 purpose in New York. 



Pan crusher. 



Pan crushers. — Of these there are two classes, viz : Dryj'pan 

 crushers and wet pan crushers. The former pulverizes the mate- 

 rial as it comes from the bank, the latter tempers it with water. 

 In either case the crushers consist of a circular pan in which 

 there are two iron wheels revolving on a horizontal axis. They 

 are made to revolve by friction against the pan which is rotated 

 by steam power. In a dry pan the bottom is perforated and the 

 wheels weigh 2000 to 5000 pounds each. The wet pan has a 

 solid bottom, in which there is a door through which the material 

 can escape when sufficiently tempered. 



A good dry pan will grind 100 tons in 10 hours through one- 

 eighth inch screens.* 



Two scrapers are placed in front of the rollers to throw the 

 material in their path. In a wet pan water is added to the clay 



* E. Orton, Jr., Clay Working Industries of Ohio, 1893, p. 142. 



