Insulated Fire Bridge for Furnaces of Marine or other Boilers..
Year: 1896

page_text: Date of Application, 31st Dec., 1896-Accepted, 1st May, 1897
COMPLETE SPECIFICATION.
Insulated Fire Bridge for Furnaces of Marine or other Boilers..
1, JAMES REAGAN, 1026 Filbert Street, Philadelphia, State of Pennsylvania,
United States of America, Engineer, 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 object of my invention is to provide a durable bridge, which will effectually
resist the action of the intense heat to which they are subject under heavy firing in
the furnace, and which will remain intact under all conditions. In furnaces,
especially of steamships, where the bridge wall is composed of fire brick they are
liable to become displaced by the slice bar striking them in loosening clinkers, and
are often pushed up, by the bar, into the combustion chamber where they impede
the draft and prevent a proper combustion of fuel. The trouble, expense, and
delays involved in the matter of bridge walls in furnaces of steaniships, where fire
bricks are used, are of considerable moment, inasmuch as the fire bricks knocked
loose in attempting to remove the adhering clinkers, are often thrown overboard
with the ashes, thus necessitating the rebuilding of the bridge wall every time the
ship:arrives in port.
My invention consists of a sectional bridge plate, provided on the upper surface
with a series of parallel grooves, chaunels or depressions for the lodgment of ashes,
and supported on the shelf running across the furnace flue separating the combustion
chamber, with the open space underneath packed with ashes. The plate is thus
sandwiched between layers of ashes which are non-conductors of heat, consequently
it is insulated and cannot be burnt out, warped or twisted, and if properly applied
will remain intact for years or as long as the life of the boiler.
The heat otherwise absorbed by the ordinary brick bridge walls will be saved
and the efficiency of the boiler increased.
Reference is had to the accompanying drawings in which::-
Figure 1, is a vertical longitudinal section through the rear portion of a
marine boiler furnace and part of the combustion chainber, showing my invention
applied.
Figure 2, is a perspective view of my invention removed from the furnace flue.
Figure 3, is a vertical section, enlarged, of a portion of the grooved bridge.
late.
Figure 4, is a modification of the same.
Figure 5, is a vertical longitudinal section of my invention as applied to furnaces
of stationary boilers..
The plate A, Figure 1, which extends across the furnace flue and forms the
bridge proper, is provided on the upper surface with a series of grooves, channels
or depressions, b, with intervening atapering ridges c, to form receptacle for ashes.
The grooves or channels b, may extend across the plate in different directions, but
they are arranged preferably in parallel rows extending from front to rear edges of
plate, so that the top or apex of the ridges c, form a suitable support for the slice
bar or hoe, and permit the same to slide freely over without dislodging the ashes.
The said plate A, is made in three or more sectious, d, d', d', of such dimensious as
o be readily passed through the fire door or other convenient opening, with their
oining edges overlapping and secured by means of tap bolts e, Figure 3; by this
neaus the fire bridge may be erected or removed without dismantling or disturbing

page_text: nny part of the boiler. Other methods may be adopted for joining these-sections
to one another to conform to different types of boilers and in some cases it may be
desirable to divide the fire bridge into numerous narrow strips, and connect the
abutting edges of same by means of lugs formed at intervals along one edge,
interlocking with corresponding sockets formed in the edge of the adjoining plate,
as shown in Figure 4.
At the rear end of each section, d, d, d, is formed a downward projecting flange
or foot, f, to support the bridge at any suitable angle upon the shelf or plate,
between the furnace and combustion chamber, of a marine or internally fired
boiler; or if it is desired to lay the plate flat, the foot is dispensed with.
When the bridge is to be inserted, the sections d, d', d, are separated and passed
through the fire door, the right and left hand sections d, and d', are first placed in
position and fine or sifted ashes packed underneath them, and in the space covered
by the intermediate section d', after which the tap bolts are inserted aud the whole
held firmly together.
It will be observed that when the plate A, is imbedded in ashes, the heat cannot
ascend to cause any damage from this direction, and with the grooves filled with
the same earthy or mineral-particles, the heat cannot penetrate from the top, thus
by the interposition of ashes or other non-conductors of heat, the plate is insulated
and fully shielded from the fire. Any other substance which is a non-conductor of
heat may be employed for filling underneath the plate and for the grooves, but
ashes are preferred as being the most suitable, as they will remain sufficiently
porous within the grooves to permit air to pass through and thus keep clinkers or
vitrified matter loose at all times, so that it will not adhere to any portion of the
plate, and may be easily dislodged and pulled off with a hoe over the top of the
fire, whereas in bridge walls of brick or other construction, the clinker will knit
fast, and to remove it, the fire must be allowed to burn down, thus causing a
corresponding loss of steam pressure.
Fire bricks can be set on edges against the flange f, which is beyond the point of
formation of clinker, as shown in Figures 1 and 5, in or next to the combustion
chamber, so as to be flush with the top of said plate so that when the hoe is used, it
will not get fast, but will slide over the bricks and resting on the ridges c,
of the plate, will be drawn forward without disturbing the ashes in the grooves.
The plate may be made of various sizes and shapes according to the type of
boiler in which it is to be used, and for stationary boilers, it may if desired, be
extended back from the top of the incline for a short distance in a horizontal
direction, as shown at A', Figure 5, and backed with fire bricks, as previously
desoribed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim.is:-
1st. An insulated fire bridge provided on the upper surface with a series of
grooves, channels or depressions for the retention of ashes or other non-conductors
of heat, and imbedded in similar substance, substantially as and for the purpose
described.
2nd. An insulated fire bridge plate, A, composed of the sections d, d', d², and
provided with a flange or foot, f, grooves, channels or depressions, b,, and ridges o,
substantially as specified.
Dated this 31st day of December 1896.
ALLISON BROS.,
Agents for the Applicant.