CLAYS OF NEW YORK 



671 



360 brick. Tracks are laid from tiie macliines tlLrough. the tunnels 

 to the kilns. The tracks are laid in two directions only, at right 

 angles to each other, and turntables are placed at the points where 

 tracks intersect. The tunnels are about 5 feet high and 4 feet wide. 

 Several methods are used to heat the tunnels. There may be a fire- 

 place at one end and a system of parallel flues under the tunnel to 

 conduct the heat. A second method is to use steam heat, the pipes 

 being laid along underneath the floor of each tunnel or along the 

 sides. Exhaust steam is used in the day time and live steam during 

 the night. Another method is to heat the tunnel by a hot blast. 

 In a good drier the natural draft should be sufficient to draw the 

 air through the tunnels. Six or more of these drying tunnels are 

 usually set side by side. Artificial drying takes from 24 to 40 

 hours. The longer the clay takes to dry, the greater will be the 

 number of tunnels needed for a given capacity. The green brick 

 are put in at the end nearest the machine and the cars with the 

 dry ones drawn out at the opposite end. It is of importance that 

 the capacity of the driers shall not exceed that of the kilns. Arti- 

 ficial driers have the advantage of permitting a plant to be run all 

 winter. The cost of flue driers is set at 25c a thousand brick with 

 coal at $2.50 a ton. 



Floor driers. Bricks are sometimes dried on floors, which are 

 either of brick or wood. Brick floors are often heated by flues, 

 which pass under them their entire length, conducting the heat 

 from the fireplace at one end to a chimney at the other. Such 

 floors are cheap, but the heat is very unequal at the two ends, and 

 a large amount of labor is involved in handling the material. In 

 some cases the bricks are dried simply by reason of a current of 

 air passing over them, no hot air flues being used. 



Wooden floors either solid or slatted, such as those used in drying 

 sewer pipe, may be used, but the cost of laying them is great, and 

 the bricks, as in the case of brick floors, require much handling. 



A very common custom abroad, not used in this country, consists 

 in having a series of pallet racks built along the top of the kiln. 



