COKING TESTS. 
By A. W. Beldkn 
EQUIPMENT. 
The ovens in which the tests of the coking qualities of coals have 
been made are of the regular beehive pattern. Of the battery of three 
ovens two are of standard size, 12 feet in diameter and 7 feet high, 
the third is 12 feet in diameter and 6 feet 4 inches high. This change 
was made by raising the bottom of one of the standard ovens 8 inches 
with well-tamped loam and bottom tile of the usual size. The object 
of the change was to bring the charge nearer the dome of the oven 
and effect a more rapid penetration of heat. 
For the first nineteen tests the small oven only was used. In the 
twentieth charge one of the 7-foot ovens was blown in, and two ovens 
were used continuously during the remainder of the work — one of each 
size. Owing to the small supply of coal it has not been possible to use 
more than two ovens, and they may, therefore, be considered as end 
ovens. Some suppose that end ovens yield results less favorable 
than those from ovens located between other heated ovens, but, 
even if this supposition is correct, the difference is fully balanced by 
the greater care bestowed on these experimental ovens as compared 
with ovens operated under normal conditions. As both of the ovens 
used are, in the sense indicated, end ovens, the results obtained in each 
are comparable one with the other. 
In charging the ovens for the first nineteen tests the larry used held 
less than 1 ton. This necessitated the filling and emptying of the 
larry six to eight times before the charge was completed. Each por- 
tion thus became hot and began invariably to gas, and often to blaze 
before the next portion of the charge was added. This unfortunate 
state of affairs is believed to be responsible, at least in some measure, 
for cross lamination and cross breakage of the coke, layers of coal as 
charged showing plainly in many of these tests in each oven drawn. 
The average time of charging with this device was about one hour. 
After the nineteenth charge a standard-size larry was installed and the 
time of charging was reduced to an average of seven minutes. With 
this change the lamination and cross breakage referred to disappeared, 
showing that the whole charge should be put in at once. 
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