This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol5", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
There are at present four types of furnaces in operation in this country. Messrs. Simons', Toisoul, Fradet & Co.'s, the Carbon Oxide Company's, and the one at the Birmingham Crematorium, designed by Messrs. Wilcox & Raikes.
Messrs. Simons' furnace consists of three chambers, the two lower of which are surrounded by air passages. The lower chamber contains a coke fire, and the upper, or cremating one, is that in which the body is reduced to ashes. The fire is lit some time before the apparatus is to be used, and is supplied with air in the usual way. Before the introduction of the body, the air supply to the coke fire is greatly restricted; and after the body has been placed in the furnace a separate supply of heated air is introduced to the hot gases from the fire. The incinerating chamber is thus filled with intensely hot gas in a state of incandescence. The process occupies about one hour, and for each cremation an average of 12 cwts. of coke is consumed.
Messrs. Toisoul, Fradet & Co.'s is a gas operating furnace. The heating gas is introduced through Bunsen burners at the back end of the chamber containing the body, and the products of combustion pass out at the side near the front or entrance end of the chamber. The hot gases are then conveyed along flues and pipes underneath the furnace in such a manner as to highly heat the air supply to the bunsen burners, as well as a separate air supply that is arranged to enter the chamber at each side of the body at the latter stages of the process. The air supply to the bunsen burners is controllable, as also is that supplied separately to the sides of the cremating chamber.
It is estimated that about 6080 cubic feet of gas is consumed for each cremation, including that used in the pilot fire in the chimney, which at 2s. 2d. per 1000 feet (the price of gas in Leeds, where this furnace is in use) costs about 13s. 2d.
The Carbon Oxide Company's furnace, which is in operation at Golders Green Crematorium, may be said to be the most satisfactory of any used in this country. It is said to only consume about 7 cwts. of coke per cremation; and further, that there is not found so great an amount of expansion and contraction, during the heating and cooling, as is noticed in other furnaces.