CLAY WORKING INDUSTRIES. 173 



latest arrangement allows of simultaneous use of exhaust steam, and 

 live steam, in any variable proportion which is desired. 



This plan probably presents the greatest perfection yet attained in 

 the art of drying bricks. The use of a fan has. many advantages over a 

 stack, and the use of a compact heater, in which the heat of the exhaust 

 can be used wherever it is available and in whatever quantity it is avail- 

 able, enables the manufacturer to do the maximum amount of drying in 

 the minimum amount of space with the minimum amount of fuel, and 

 attention. The efficiency to which these dryers actuated both by stack 

 or fan are now brought is shown by the fact that there are several firms 

 willing to make guarantee contracts to dry a daily output of any size, in 

 twenty-four hours with not over one per cent, loss by crackingln any 

 kind of clay, at a final cost of about $1,000.00 for every 5,000 brick per 

 day to be dried. This cost includes the dryer complete with tracks, turn- 

 tables, iron cars and transfer cars — in fact everything necessary to the 

 operation of a progressive dryer with the car system. The cost per 

 thousand after the dryer is in operation depends on the fuel, on whether 

 live or exhaust steam be used,, and in the arrangements of filling and 

 emptying the dryer. Under good conditions the cost can be reduced be- 

 low twenty cents per 1,000. 



In most brick plants the exhaust steam of the engine if applied in 

 a condensed space and used to impart a low heat to a large body of air 

 under constant motion, is sufficient to do three-fourths of the drying. 

 Economy demands that either the waste heat of burning or the waste 

 heat of manufacturing should be used. 



Two plans are open to the manufacturer who wishes to get the maxi- 

 mum economy in running expense, rather than the minimum first, cost 

 of investment. 



Either the exhaust , steam of his engine shquld be made to do all 

 that it is able to do toward drying the daily product, in which case he is 

 justified in using a common engine not especially economical of steam, 

 or he. must dry .his bricks, by the waste heat of the burning processes, 

 and get the utmost efficiency out of the boiler fuel by use of compound 

 condensing engines* 



The waste of fuel now going on in most of the brick factories in 

 the .drying process seems almost as criminal as the fearful waste. in min- 

 ing the coal from its underground resting place. , 



. iMany factories are employing low grade steam engines, whpse best 

 economy of steam consumption is very poor, and are over-burdening 

 them so that not over one-half of the possible economy is attained, and 

 then are throwing away into , the air the heat which would more than 

 suffice to dry their whole output. In addition, they calmly proceed to 

 draw on their already over-taxed boilers for Jive steam for their dryers or 

 else use the still worse plan of burning up fuel direct. for this purp se, 

 And to all these wastes the burning and cooling kilns of brick are every 



