Beehive oven

Its apex of popularity occurred in the Americas and Europe all the way until the Industrial Revolution, which saw the advent of gas and electric ovens.

However many coals can be converted to coke, a hard and highly carbonaceous mineral foam well suited for fueling blast furnaces, by distilling off the volatile components.

Each bank face had a oven door sill level platform for holding and cooling coke, above a RR track for shipping it.

Given a hot oven, the coking cycle begins by adding coal from the top and leveling it to produce an even layer of about 60–90 centimetres (24–35 in) deep.

As the coal heats, it softens into a tarry mass permeated with bubbles of evolving distillate, which give the coke its characteristic cellular structure.

Complete distillation is marked by much reduced gas production, at which point the top hole is covered until the coke can be withdrawn.

As the coke is still hot enough to ignite on exposure to air, it is cooled in the oven by introducing water concurrently with unbricking the door.

Ideally the next cycle starts immediately after pulling the previous charge, to make maximum use of the oven's retained heat.

[4] Cycle time varied with the raw coal's chemical and physical character, particularly the percentage of volatiles, and with the initial depth of a charge, the rate that air is introduced, and promptness of pulling the coke and recharging.

As the fire caught, more kindling was added to produce a thick smoke, which coated the oven with black soot.

"The smoke and gas from some ovens destroy all vegetation around the small mining communities," noted W. J. Lauck of the U.S. Immigration Commission in 1911.

[9] Passing through the region on train, University of Wisconsin president Charles van Hise saw "long rows of beehive ovens from which flame is bursting and dense clouds of smoke issuing, making the sky dark.

The beehive ovens make the entire region of coke manufacture one of dulled sky, cheerless and unhealthful".