METHOD OF MANUFACTDRING BKICK 



169 



The auger machine consists of a cylinder with a conical end. In 

 this is a horizontal shaft bearing a screw or knife blades so set that 

 their action will force the clay forward. At the forward end of the 

 shaft is an iron screw which forces the clay out through the die. 

 The clay is fed at the large end of the cylinder. It will thus be 

 seen that the clay undergoes a large amount of compression and 



Auger machine. 



that considerable power is required to force it through the die. 

 Auger machines are either end cut or side cut according as the 

 area of the cross section of the bar is the same as the end or side 

 of a brick. The great objection to this form of brick machine is 

 the spirally laminated character which tlie brick has, owing to 

 the manner in vvhich the clay is forced through the die. Never- 

 theless this machine is extensively used at the present day, 

 especially in the manufacture of paving brick. It has a large 

 capacity, 60,000 brick being not an unusual output for 10 hours. 

 The capacity of the auger machine is often increased by causing 

 two streams of clay to issue from it and certain machines are 

 said to have produced 150,000 brick per day. Plunger machines 

 have a capacity of 25,000 to 3o,000 per day. 



The green bricks are usually piled on cars and these are run 



into heated tunnels to dry. If soft mud bricks are dried in 



tunnels then the cars must have racks on Avhich to set the 



pallets bearing the bricks. Stiff mud bricks can, however, 



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