KILNS.
THE question of what method of burning to adopt or what class of kilns to employ is one which must be largely governed by local circumstances. If the works are not located near clay fields which promise to yield clay in sufficient quantities to warrant the erection of permanent kilns, then, of course, the only thing to be done is to use temporary kilns or " clamps." Ordinarily the fuel in temporary brick-kilns or clamps is placed within the arches either directly upon the ground, when wood is used; or upon grates extending through the entire length of the arches. This mode of firing is objectionable, for the reason that it is commonly very difficult to regulate the fire so as to produce brick of uniform color and strength.
The kiln shown in Figs. 73, 74, 75 and 76, which is that of Mr. Wm. H. Brush, of Buffalo, N. Y., is designed to remedy the difficulties and objections named.
Fig. 72 is a sectional elevation, showing an arch of a brick kiln provided with the Brush improvements. Fig. 73 is a plan view of two arches. Fig. 74 is a front view, showing one arch in front elevation, and one in cross-section. Fig. 75 is a rear view, and Fig. 76 a horizontal section of the fire-door.
A represents the arch of green brick set up in the usual manner. B are the frames of the fire-doors, arranged in the outer walls of each arch in the ordinary manner. C is a fire grate, preferably about five feet in length, arranged within each arch, at each end thereof, as clearly shown in the drawing. The grates C are supported upon bars d d' resting upon the brick of the ash-pit D, which latter is preferably composed of old or burned brick. E is an inclined plate or apron hinged or hung to the rear grate-bar d', as clearly represented in the draw ings, and made of the same widt4 as the ash-pit, so as to pre vent the cold air in the ash-pit from entering the arch, except through the burning fuel upon the grate C. The aprons E incline toward the ash-pit door F, so as to cause the ashes and cinders dropping upon the aprons to slide forward toward the ash-pit door ; and the hinging of the aprons to the grate-bars enables the front ends of the aprons to be raised, so as to per mit access to the fuel placed upon the ground between the grates C C.
G is the fire-door, hinged to the frame B, and provided with vertical slots or openings g, which are opened and closed by a sliding-plate g', in the manner of an ordinary register.
H is a protecting-plate, arranged on the inner side of the fire door G, and connected thereto by stay-bolts h in the usual manner : i are vertical slots or openings, arranged in the plate H in such a manner that solid portions of plate H are opposite the openings g of the fire-door G, and the openings i opposite the solid portions of the fire-door. This construction of the protecting-plate H causes the air-currents entering through the openings g of the fire-door to impinge against the solid portion of the plate H, which, being kept at a very high temperature by the fire upon the grate, heats the air before it enters the arch, thereby preventing the brick from becoming checked.
The grates C may be charged with wood or coal, and the space C' between the grates is preferably charged with wood or coke. By admitting a strong air-current through the fire-doors G, the flame and hot gases are driven from the grates C toward the center of the kiln, and the combustion of the fuel between the grates is accelerated. Upon closing the damper in the fire door G, the hot gases from the grates C rise perpendicularly through the arch, and the combustion of the fuel between the grates is retarded. Upon raising the ends of the aprons E, the ashes can be raked out from the space between the grates, and new fuel can be supplied thereto without interfering with the fuel upon them, while, by supporting the front ends of the aprons in a greater or less elevated position, the combustion of the fuel in the space between the grates can be regulated with out affecting the combustion of the fuel upon the grates.
It is obvious from the foregoing description that these im provements, which are readily and cheaply applied to kilns of ordinary construction, give control over the fires in all parts of the arch, thereby enabling the brick to be burned to a more uniform color than in clamps as ordinarily constructed.
The entire fire-surface being arranged within the arch, the heat developed by the fuel is fully utilized, and loss from radiation, while not of course fully prevented, is to a great extent curtailed.