COKE 



891 



been introduced at the Thornclifie collieries. The following objects are aimed at in 

 the construction of the Coppee ovens : 



1. The retention (as coke) of as large a proportion of the carbon contained in the 

 coal as possible. 



2. The utilisation of the heat of the gases given off) by the use of flues arranged 

 to maintain a high temperature, and applied in such contiguity to the oven itself as 

 to hasten, by imparting an intense heat to the inside of the oven, the expulsion of the 



3. As a secondary, but consequent consideration, the application of the heat 

 retained by the gases when they leave the stack of ovens, to the production of 

 steam. 



The Coppee ovens have each the form of a parallelogram, the usual dimensions 

 being: length, 29 feet 6 inches; breadth, 18 inches; height, 4 feet. These are 

 charged with coals every 24 hours. When built to be drawn every 48 hours, the 

 ovens have the same length, but are built 5 feet 7 inches high and 24 inches broad. 

 The thickness of brickwork between the ovens is 13'2 inches. 



The coals, whether washed or otherwise, are crushed or disintegrated before being 

 placed in the oven to the consistency of very coarse meal. At each end of the oven 

 are two metal doors moving on hinges, and fixed securely in metal frames, the lower 

 being 3 feet, and the upper 1 foot in height. Between each two ovens are about 28 



500 



vertical channels, v v (fig. 500), which, leading from one side of each oven, convey the 

 gases down to the horizontal flues, H H, one of which runs under each oven. The ovens 

 are arranged in groups of two. The gases from each two ovens, A A or B B, take their 

 course down vertical channels to the horizontal flue under one of the ovens, entering 

 such flue by the apertures c c. The combined gases, after passing along this flue to the 

 end of the oven, return by the flue under the other oven, and enter, at the point p, 

 into a large channel running at right angles to the ovens, j. They pass from 

 this channel, either directly into a chimney, or are carried under one or several 

 boilers. 



At the commencement of the burning the admittance of air is regulated by three 

 small channels, by means of each of which air can be conveyed to the top, either of 

 the oven, or of the vertical flues. One of these air-passages is in the centre of the 

 oven, and is worked by the doors, D D, and the others are fixed at each end of the 

 oven, at the side of the doorway, as shown by p F, a very simple arrangement of 

 sliding doors allowing the air to be applied or shut off, with great facility and 

 promptness. 



The coke is removed from the ovens by means of a ram, propelled by a cogged 

 driving-wheel, which is worked by a small portable engine. 



