Improvements in Fire Brick Arches, Crowns, or Roofs for Furnaces and Ovens.
Year: 1899

page_text: Date of Application, 3rd May, 1899-Accepted, 23rd Sept., 1899
COMPLETE SPECIFICATION.
Improvements in Fire Brick Arches, Crowns, or Roofs for Furnaces
and Ovens.
I, HENRY SECHRIST VROOMAN, of 220, W. Twentieth Street, Chicago, U.S.A.,
Manufacturer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
-
The objects of my improvements are to provide an arch, crown or roof for
furnaces and brick built ovens with arched roofs which shall be stronger than the
arches composed of the common tapering or keystone shaped bricks; in which there
will be no possibility of the bricks dropping out of the arch when the latter
expands or the bricks contract from changes of temperature, or when the side walls
spread as they frequently do; in which there will be no diminution of wearing
or burning. surface as compared with the arch bricks ordinarily used in furnaces,
and in which there will be increased binding or wedging exerted by the various
bricks composing the arch.
In carrying out the objects above set forth I employ fire bricks of peculiar
comformation and adopt a construction the novel features of which are illustrated
in the accompanying drawings which form a part of this application, in which:-
Fig. 1 represents in elevation, a furnace arch constructed in accordance with
my ideas.
Fig. 2 is a perspective view of the fire-brick composing the body of the
arch
Figs. 3 and 4 are perspective views of the fire-brick forming the respective
ends of the arch.
The body of my improved arch is composed of a plurality of bricks B, the
number employed depending on the span of the arch to be built. The diameter
of the span and the rise of the arch also affect the variations in the cross diameters
of the upper or extrado edge of the brick, and the lower or intrado edge of the
brick composing the arch. The brick B may be of any suitable vertical or cross
diameters, and the proportions and degree of inclination of the angles shown in
the drawing, may be varied without departure from the principles involved in its
construction. For ordinary purposes the brick B is preferably formed with its
upper and lower edges parallel, and with its upper inclined faces 6, 6' about one-third
the vertical diameter of the brick but this may be varied. The cross diameter of
the upper edge 6 of the brick is greater than the cross diameter of the lower
edge 65, and there is a gradual taper between said edges which extends throughout
the vertical diameter of the brick, thus giving a key-stone or wedge-shape con-
figuration to the sides of the brick.
The ends of the arch are formed with bricks A and C, respectively. The
brick A is formed with a straight face a, with outwardly inclined faces a¹, a², and
with its upper and lower edges parallel and the cross diameter of the upper edge a³
is greater than the cross diameter of the lower edge a, as shown in Fig. 3. The
angle or inclination of the face al somewhat less than 45 degrees and the angle

page_text: of the face a is greater than 45 degrees, in the brick shown, but as above stated,
these angles are varied in the construction of arches of different diameters. The
brick has its upper and lower edges parallel and said edges formed
at approximately right angles to the side face c which is straight.
The opposite faces. c¹ and are inwardly inclined, their proportions
and the angles of inclination corresponding with the faces 6 and 62 of the
bricks B. The cross diameter of the upper edge of the brick C is preferably
slightly greater than the cross diameter of the lower edge, as clearly shown in
the detail of said brick, Fig. 4.
In the construction of my improved arch, I place the brick A with its straight
face a to the inclined face d at the upper end of the wall or abutment D) and
with its wider edge to the extrado face of the arch, I then set the bricks B in
position to form the body of the arch, and at the opposite wall or abutment E, I
set the brick C with its straight face to the upper end e of the wall, when the arch
is complete.
I have shown in the accompanying drawings an arch formed with brick in
which the angle formed by the inclined faces meets at a point above the longi-
'tudinal center of the brick. The object in thus constructing the brick is to give
greater wearing surface then would be possible if such angle was below or at
the center. Thus the brick may be worn or burned away more than one-half of
its vertical diameter, and still be supported by the shoulder formed by the angular
faces. A further advantage of having the converging line of the faces above
the horizontal centre, is that the bricks expand to a greater degree at their lower
edges than at the top, and the angle forms, to a certain extent, a pivotal point on
which they turn in the direction of their line of expansion. If this point was
below the centre the upper edge of the arch would be expanded to a greater degree
than with the point where it now is.
From the construction shown, it is apparent that in addition to the lateral
bearing afforded by the tapering or wedge shape of the bricks B, bearing is also
maintained between the contiguous faces b and b¹, and between 2 and 63, the
angular sides of which form shoulders which afford direct support to the super-
imposed bricks, the line of pressure being vertical to the axis of the circle of
which the arch is a segment. Thus an arch may expand not only to the extent
equal to the variation between the diameter of the upper edge of the brick
and the lower edge (as in the common form of wedge-shaped brick) before a brick
can fall out, but it may also expand to the extent of the diameter of the inclination
from the vertical line of the combined faces 6 and 61, before there is any possibility
of the brick dropping out. The same condition applies when the bricks shrink
as they always do after being exposed continuously to great heat.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I consider novel and desire to claim is:-
1. A fire brick arch crown or roof comprising bricks having their upper edges
wider than their lower edges, and gradually tapering throughout their length
between said edges, and having one side formed with two inwardly inclined faces,
and the opposite side formed with two outwardly inclined faces, said inclinations
extending from the upper and lower edges of the bricks, respectively, and
meeting at a point above the longitudinal centre of the bricks, substantially
as set forth.
2. An arch crown or roof comprising interlocking tapering bricks, each having
a shoulder on one of its side faces, and a corresponding depression on its opposite
face, said shoulder having their greatest cross diameters at a point above the
longitudinal centre of the brick, an end brick having faces corresponding to the
contiguous faces of the intermediate brick, substantially as set forth.
3. An arch crown or roof comprising one end brick having a plane face, and its
opposite side formed with inwardly inclined faces meeting at a point above the

page_text: centre of the brick, another end brick having a plane face and its opposite side
formed with outwardly inclined faces, meeting at a point above the centre of the
brick, and intermediate bricks having their respective faces corresponding to the
contiguous faces of the end brick, substantially as set forth.
4. An arch crown or roof composed of one end brick having inwardly inclined
faces converging at a point above the centre of the brick, a second end brick having
outwardly inclined faces converging at a point above the center, and intermediate
bricks having their opposite sides corresponding respectively to the outwardly
inclined and inwardly inclined end brick, substantially-as set forth. -
D
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.