Public domain works must be out of copyright in both the United States and in the source country of the work in order to be hosted on the Commons. If the work is not a U.S. work, the file must have an additional copyright tag indicating the copyright status in the source country. Note: This tag should not be used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:AmCyc_Brick_-_Hoffmann%27s_Annular_Brick_Furnace_(side).jpg
Description:
A large annular chamber,
with openings at the sides for the reception of
the bricks, is constructed with a central chimney,
and with removable divisions for separating
the annulus into different parts. When
the furnace is filled with unburnt bricks heat
is applied to one division, the smoke and hot
air escaping into the adjoining one, which is
the next to be burnt, the air for maintaining
the combustion being received through the
compartment last burned, whereby the bricks
in it are cooled. Each compartment of bricks
or other articles is thus burned in turn, the
waste heat of the burning compartment continually
drying the compartment before it, and taking
all the heat of the one behind. The letters
a a mark the circular arched furnace,
furnished with doors, b b. Flues, c c, lead to the
circular chamber e e, surrounding the chimney,
d. Valves of cast iron are made to close at pleasure
the orifices of the flues. Movable sluices
in the dividing walls allow of communication
to be made or closed between the chambers;
h h are plugs through which the coal, in
powder, is introduced, undergoing calcination.
Captions
Add a one-line explanation of what this file represents
{{Information |Description ={{en|1=Woodcut/drawing of an annular brick furnace (side view), designed by Friedrich Hoffman.}} |Source =''The American Cyclopædia'', v. 3, 1879, p. 267 (Fig. 1, top). |Author =unknown artist/Friedrich H...