IMPROVEMENTS IN FURNACE BARS AND BEARERS
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by Jonathan Mitchell at the Office
of the Commissioners of Patents, with his Petition, on the 19th
January 1872.
I, JONATHAN MITCHELL, of Dyson Street, Bradford, in the County of
York, Contractor, do bereby declare the nature of the said Invention
for "IMPROVEMENTS IN FURNACE BARS AND BEARERS," to be as follows:-
My Invention has for its object improvements in furnace bars and
bearers, and relates to an improved form of furnace bar and an arrange-
ment of bearers for fire-bars as herein-after described.
My improved bar is arranged to lie transversely on the longitudinal
square bars of the bearers, and is in construction similar to two
transverse bars about 4 inches apart (more or less) united by short
bars stretching from one to the other about one inch apart (more or less)
throughout their length; the upper sides of the bars are all by

page_text: preference grooved and all taper downwards so as to be capable of being
readily freed from clinker. To prevent these bars from lying in contact
transversely, small projections or distance pieces are cast or formed on
their outer sides. The bearers are arranged as follows:-I place across
the furnace at the points where the bars are desired to rest two or more
flat wrought-iron bars which may rest loosely on suitable brickwork or
brackets, or if placed in an internal boiler furnace may be cut to fit at
their ends to the sides of the same, no fixing in any case being required.
Each of these flat bars carries two or more cast-iron chairs, the under
sides of which are recessed so as to fit on to the flat bars and be capable
of sliding longitudinally along them or in a direction transverse to the
furnace; the upper sides of these chairs are grooved in the shape of the
letter V, the direction of the groove being transverse to the flat bars and
in the line of the furnace. In these V grooves rest longitudinal
wrought-iron square bars in such position that their diagonals are in a
vertical and horizontal direction. Two or more of these longitudinal
square bars are required according to the breadth of the furnace. On
the top corners of these longitudinal bars rest transversely several flat
wrought-iron bars placed edgewise, their number being proportioned
to the length of the furnace, and on these again rest longitudinally the
bars proper of the furnace which may be of the kind herein-before
described, or they may consist of bars furnished with small projections
on their sides to keep them from approaching too closely to each other,
and having also an indentation cut in their under sides to fit on to the
edges of the transverse bars which carry them; this indentation prevents
the said transverse bars from being shifted out of their right position
under the furnace bars, while every part is nevertheless left free for
expansion, removal, or adjustment.
In the case of furnaces of great width in order to insure a uniformity
of distance between the bars I substitute for the flat wrought-iron bars
placed edgewise above referred to a cast-iron bearing bar considerably
deeper than it is wide at its bottom side and tapering upwards towards
the ton edge, the ton edge being cut in a series of grooves or notches.

page_text: not only to fit into but on to their bearers, so that the whole network of
bars is held together by the simple weight of its parts, and at the same
time free to expand and contract in every direction, and offering every
possible facility for renewal, cleaning, and adjustment.