168 GEOLOGY OF OHIO. 



be spent in any event, in the production of power. During the balance of 

 time they expect to use a little live steam to supplement the exhaust 

 provided by the power plant. 



If the floors are smaller and the time which can be allotted to the 

 bricks to dry is limited, then the use of live steam becomes necessary all 

 the time, and while the drying that is secured is still of a good quality, 

 the use of the heat is not an economical one Many more feet of pipe 

 are required to accomplish a given amount of drying by this way than 

 will be required by other plans; hence the only economy of the process 

 consists in the possession of ample space and equipment, so that by the 

 use of the waste steam and time, the work can be done without extra 

 fuel. 



Chamber Dryers. The plan of action of the chamber dryer consist 

 in exposing the brick piled in open bulk to the drying influences of heat 

 and air currents continuously until they are dry and then emptying and 

 refilling the dryer for another change. The dryers are usually built on 

 what is know as the Tunnel System; the compartments are long, low 

 rooms, arranged in parallel order, each compartment being provided 

 with its own heat supply, air supply, and draft arrangement, to carry 

 off the steam and vapor and each compartment being equipped with its 

 own doors, and means of control of all the necessary conditions. In 

 some places, the output is suah, that two chambers can do all the work, 

 one being filled and emptied every day while the other is drying its 

 charge. Elsewhere, three compartments are needed, one being filled, 

 another drying and another emptying. Again there may be a large 

 number of compartments operated in rotation as indicated. The 

 methods of generating heat and air currents and draft are essentially the 

 same in these dryers as in the next class and will be described later. 



The principle of their action, that of drying a charge by itself and 

 under conditions that it is some one's business to keep right, is a good 

 one. It connot be assailed on any theoretical grounds. But in practice, 

 the dryer is emptied and filled with its air currents and heating arrange- 

 ments inoperative, and when it is full of a given number of bricks, the 

 heat and air flow is usually put into operation at once. There is great 

 danger of cracking the brick at this stage and only the most skillful 

 manipulation will prevent it. 



Progressive Dryers, sre those which are being constantly filled with 

 greensware at one end, and emptied of dry ware at the other. 



The use of this principle depends on some means of advancing the 

 position of the bricks along the dryer, at will. The means adopted in 

 almost all cases, is by use of iron or wooden cars, each capable of carry- 

 ing a good load of brick without great use of power in moving it. 



The use of the car system is not at all confined to progressive 

 dryers, but of the progressive dryer it is an integral part. 



