HARDWOOD DISTILLATION 209 



used in the oven retorts. The retorts are set in brickwork in pairs, 

 each pair forming a battery and heated directly from beneath. They 

 are charged and discharged from a single door in front which can be 

 hermetically sealed. Considerable labor is involved in the charging 

 and discharging of these retorts, and the ovens with the cars running 

 directly into them on tracks are a great improvement. With the inven- 

 tion of the ovens in the early nineties very few of the old, round retorts 

 were installed. In fact, all of the new plants being installed are equipped 

 with the long oven retorts. 



Ovens. 



The oven or oven retort is a vast improvement over the round retort, 

 the chief advantages being that a large amount of wood can be distilled 

 at one time and considerable labor is saved in charging and discharging 

 the ovens, the loaded wood cars being run directly in from one end on 

 tracks and hauled out by means of a cable on the other end to the first 

 cooling oven. 



These ovens in cross-section are 6 ft. 3 in. wide and 8 ft. 4 in. high. 

 In length they vary from 25 ft. to 50 ft., although the usual length used 

 at the present time is a 52-ft.' oven which holds 4 cars. These ovens are 

 usually installed in batteries, that is, 2 ovens being placed close together 

 and called a battery. In Michigan there are as many as 7 to 10 batteries 

 in a single plant. The largest New York plant contains 8 ovens and is 

 located at Corbett in Delaware County. Altogether in New York State 

 there are 46 ovens distributed over 10 plants. 



These ovens have air-tight doors on one or both ends, depending upon 

 whether the charcoal is to be taken out in the same direction as it entered 

 or sent out through the progressive form of trackage arrangement. 

 The ovens are of steel, usually three-eighths of an inch in thickness, while 

 the bottoms and backs are of |-in. material. The oven is sustained by 

 means of angle irons riveted perpendicularly on the sides and on one side 

 near the top are riveted cast-iron nozzles, usually two in number, which 

 are attached to the condensers. In the heating process it is said that the 

 52-ft. oven will expand 4 in. in length due to the tremendous heat applied 

 during distillation. These ovens last only from three to twelve years, 

 so that the depreciation charge is very high. 



The 52-ft. oven costs about $1800 apiece and approximately an equal 

 amount is required to install and set it up ready for operation. 



Cooling Ovens. 



In every oven retort plant the charcoal is gradually cooled by being 



