Page:Popular Science Monthly Volume 39.djvu/757

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on the left having been removed to show the flues. The distinguishing peculiarity of the "Siemens furnace" is the method of utilizing the escaping heated products of combustion for heating the incoming gas and air. This is accomplished by what are called the "regenerative chambers," which are situated to the right and left of, and at a lower level than, the "melting holes." As will be seen in Fig. 51, there are four of these chambers, the two smaller being for gas, and the two larger for air.

Air enters the flue at the lower part of the left-hand chamber, and, passing upward, it absorbs whatever heat may be in the reticulated mass of fire-brick with which the chamber is filled, and, on reaching its top, it turns to the right in the direction of the arrow, and, just previous to entering the "melting hole," it encounters and combines with the incoming gas, which also has been highly heated by contact with the bricks in the "gas chamber." The result is the ignition of the gas immediately at the entrance to the "melting hole"; intense combustion ensues, the ignited gas expanding and completely enveloping the "pots," and the highly heated products of this combustion leave the "melting hole" on the side opposite to that at which they entered, and on their way to the chimney they pass through each of the right-hand chambers of the furnace, and in their passage raise the bricks therein to a high temperature.

After the furnace has worked for a proper time in the way