Improvements in connection with the Furnaces of Steam Boilers.
Year: 1889

page_text: Date of Application, 13th Nov., 1889
Complete Specification Left, 24th June, 1890-Accepted, 26th July, 1890
PROVISIONAL, SPECIFICATION.
Improvements in connection with the Furnaces of Steam Boilers.
We CHARLES THORNES PHILLIPS, woollen manufacturer and ROBERT ARCHER
engineman, both of Ossett in the County of York do hereby declare the nature of
this invention to be as follows:-
The object of our Invention is to regulate the height of the bridge of the furnaces
of steam boilers, and more especially to do this in an automatic or dependant manner
by the opening of the furnace doors, so that on opening the furnace doors the bridge
may be raised to its highest position, lessening or obviating the liability of over-
throwing the fuel past the furnace; whilst when the furnace doors are closer the
bridge occupies its lowest position, allowing a fuller flue-area for the passage of the
heated gases and flame beyond the fire grate, and thereby lessening the intense local
heat at the crown of the fire boxes and at the upper part of the foremost cross or
Galloway tubes, and allowing the flame and heated gases to act over a larger portion
of the circumference of the flues and of the depth of the cross tubes in tho
neighbourhood of the fire-bridge.
Our Invention consists in making the fire-bridge moveable, either by hingeing
the bridge at its lower edge, in which case it is arranged to be swung backwards
and downwards on such hinge; or by making the bridge moveable in vertical guides.
When the level of the back end of the fire-bars is lower than the centre of the flue,
it is impossible to make the whole width of the bridge moveable, we therefore make
only that part (ie. about two thirds to three fourths) of the full width of the bridge
noveable, for which there is space to move it in, as above described (i.e. vertically
or radially). The lower part of the bridge, in the case where the motion is radial,
is so constructed that its motion does not open any wide passage between it and the
back end of the grate bars for the admission of cold air. By means of chains and
pulleys, or of levers and links or rods, the moveable part of the bridge is connected
with the fire-hole doors, or with the hinge pin of the same, in such a manner that
the opening of the firing doors raises the bridge, and the closing of the doors lowers
the bridge. When the motion of the bridge is vertical, the sides of the samo are
guided by fixed bars, or the fixed sides of the bridge. When the moveable bridge is
comparitively heavy, or when it is lined with fire-brick, we employ a balance weight
or weights to facilitate the raising of the bridge on the opening of the doors.
In many cases it is of advantage to be able to adjust the height of the fire-bridge
to suit varying conditions of draught, quality of fuel, and of the mode of admitting
and the amount of air admitted either in front of or behind the bridge. In such a
case, we make the connections for raising and lowering the bridge (automatically
by the opening and closing of the firing doors), capable of being disconnected from
the door, and of being operated by hand, or we provide independant means for
raising and lowering the bridges.
Dated this 9th day of November 1880
J. CLARK JEFFERSON, Å.R.S.M., Wh. Sc.,
2, East Parade, Leeds, Agent for Applicants.
COMPLETE SPECIFICATION.
Improvements in connection with the Furnaces of Steam Boilers.
Wo CHARLES THORNES PHILLIPS Woollen Manufacturer and ROBERT ARCHER
Engineman both of Ossett in the County of York, 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 our Invention is to regulate the height of the bridge of the furnaces

page_text: of steam boilers, and more especially to perform this in an automatic manner
dependant on the opening and closing of the furnace doors, so that on opening the
furnace doors the bridge is raised to its highest position lessening or obviating the
liability of overthrowing the fuel past the furnace, whilst when the furnace doors are
closed the bridge occupies its lowest position; allowing a fuller flue area for the
passage of the heated gases and flame beyond the fire grate and thereby lessening
the intense local heat at the crown of the fire boxes immediately over the bridge
and at the upper part of the foremost cross or Galloway tubes; and allowing the
flame and heated gases to act over a larger portion of the circumference of the flues
and of the depth of the cross tubes nearest the fire bridge.
Our Invention consists in making the fire bridge moveable; either by hinging the
bridge along or about its lower edge, in which case it is arranged to swing
backwards and downwards about such hinge; or by making the bridge moveable
vertically or approximately so. When the level of the back end of the fire bars is
lower than the centro of the flue, it is impossible to make the bridge of the full
width of the flue and at the same time capable of being swung from a vertical into a
horizontal position; we therefore make the bridge of a width loss than the diameter
of the flue, usually from three fourths to seven eights the flue diameter. The bridge
is generally constructed so that the hinge forms its lower edge. The back end of the
ashpit below the grate bar level is usually closed by a fixed partition.
Where the motion of the bridge is vertical its width is made preferably about equal
to the length of a horizontal chord of the flue circle at the level of the top edge of
the bridge, when the bridge is raised into its highest position. The sides of the
bridge may be guided in vertical guides attached to the sides of the flue, and they
close the space between the sides of the flue and the sides or edges of the bridge;
though it will generally suffice merely to hinge the lower part of the bridge to the
lifting levers (afterwards referred to), the upper end being guided in the slit in the
bridge plate. The depth of the bridge may be such, that when the bridge
is in its lowest position, the bottom of the bridge reaches to the bottom of
the flue.
In order to raise and lower the bridge we provide a lever or pair of levers attached
to a horizontal cross shaft, the free ends of these lovers engaging in slots or slits in
the lower part of the door. The horizontal cross shaft in the case of a vertical
moveable bridge corresponds to the hinge of the swing bridge.
By means of a lever fixed on the hinge or the horizontal cross shaft, and a long
connecting rod or link, the bridge is operated from an eccentric and cam arrangement
attached to the lower end of the vertical door spindle; this arrangement being such
that unless the bridge is excessively heavy (in which case it may be balanced), the
bridge will remain in any position to which it may have been raised or lowered by
the more or less partial opening of the door. In many cases it is of advantage to be
ablo to adjust the height of the fire bridge to suit varying conditions of draught,
quality of fuel, and the mode of admitting air to the furnaces, ashpit or flues, beyond
the bridge. In such a case wo make the connections for raising and lowering the
bridge automatically (by the opening and closing of the furnace door), capable of being
disconnected from the door, so that they can then be operated by hand at will, or
independant mechanism may be provided for operating the fire bridges, as well as
from the furnace doors.
The disconnecting arrangement consists of a pivotted or hinged clutch lever, and a
catch rod, the one attached to the eccentric and crank arrangement before mentioned,
and the other to the connecting rod or link. By raising or depressing the clutch
lover as the case may be, the connecting rod or lever is released, the arrangement
being also such that by closing the furnace door the clutch connection is again
established.
And in order that our Invention and the manner in which the same is to or may
be performed reference is given to the accompanying drawings which illustrate the
general features of our Invention.

page_text: DESCRIPTION OF DRAWINGS.
Fig. 1 is a horizontal section of a furnace flue shewing our improvements in plan.
Fig. 2 is a vertical section corresponding to Fig. 1, the fire bridge in both being
supposed in its lowest position.
Fig. 3 is a part vertical section in the neighbourhood of the fire bridge shewing
the same in its highest position.
Fig. 4 is a cross section on lines X X Figs. 1 and 2.
Fig. 5 is a front view of the furnace flue shewing the furnace door closed.
In all the above figures the arrangement shown is that in which the fire bridge is
moveable vertically or approximately so.
Fig. 6 is a vertical section in the neighbourhood of the fire bridge where the
fire bridge is hinged at its lower end so as to be capable of being moved radially.
Figs. 7 & 8 are respectively plan and sectional elevation of the eccentric and cam
arrangement and of the release clutch arrangement.
In all the drawings the same letters refer to the same or similar parts.
a is the moveable bridge.
bare the vertical side guides or closing pieces.
c is the horizontal cross shaft (or the binge to which the swing bridgo a Fig. 6) is
attached.
dare levers attached to the horizontal cross shaft and engaging in slots or slits
in the lower part of the bridge a.
fis a lever fixed on the horizontal cross shaft or hinge c and connected at its free
end to the connecting rod or link g. This latter is connected at its front end either
directly to the eccentric / or to the bracket of the catch rod i. Figs. 7 and 8.
jis the door hinge or spindle on the lower end of which the crank k is fixed,
and is the eccentric mounted on the pin of the crank k.
m is the releasing catch lever pivotted in the frame n which is attached to the strap
of the eccentric h.
Our Invention operates as follows :--
When the door of the furnace is closed the fire bridge a rests in its lowest position
as shewn in Figs. 2 and 4 by full lines. The opening of the furnace door rotates
the hinge and with it the crank and the eccentric h in the direction shewn by
the arrow. This movement pulls the rod or link g and rotates the horizontal cross
shaft or hinge c, all in the directions indicated by the arrows, raising the moveable
bridge a when the door is well thrown back into its highest position as shown in
Fig. 3 by full lines and in Figs. 4 and 6 by dotted lines.
The
arrangement of crank k and eccentric h gives an increased throw or movement
of the connecting rod or link g, and is of such a nature that it counteracts the tendancy
of the weight of the fire bridge to close the door, so that the door and fire bridge
will remain stationary in any position to which they may be moved.
When it is desired to disconnect the door from the fire bridge so that the latter
may be moved without moving or opening the door, the free end m² of the releasing
catch lever is depressed by hand, raising the opposite end m into the position
indicated by dotted lines, thus releasing the catch rod i. This may then be pulled
forward by hand, and by means of the notches e on the underside, it, and consequently
also the fire bridge may be adjusted in any desired position. p is a flat plate or
bracket attached to the side of the flue and having a lip or projection p³ to fit the
notches on the underside of the rod i and hold it and the bridge in any position to
which it may be adjusted by hand. If the notches e are disengaged the fire bridge
may be allowed to drop into its lowest position when the heavy clutch end m of the
clutch lever drops into position, so as to engage with the projection on the
clutch rod i thereby automatically connecting the fire bridge again with the furnace
door.
In the modification shewn in Fig. 9, the connecting rod is provided with a pin r
rranged so as to drop into a hole in the bottom of the trough or guide bracket n

page_text: attached to the eccentric. m³ m is the releasing lever connected to the connecting
rod g, and passing through the staple or hook attached to the underside of the bracket
or trough n. It will be evident that by depressing the handle t of the releasing
lever m, the end of the rod y carrying the pin is raised so as to disengage the rod
from the bracket n, and that the rod g can then be pulled forward or moved backwards
from the handlot independant of any movement of the furnace door.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1° A moveable fire bridge so connected with the furnace door, that it is automatically
raised and lowered by the opening and closing of the said door.
2° A moveable fire bridge so connected with the furnace door, that it may be
moved either automatically by the opening and closing of the door, or by hand.
3° A moveable fire bridge moveable vertically or approximately so and operated
by levers on a horizontal shaft, or a hinged fire bridge moveable on a hinge, the said
horizontal shaft or hinge being operated by means of connecting rod by the opening
and closing of the furnace door.
4° The crank and eccentric arrangement substantially as and for the purpose herein
set forth and illustrated.
5° The release mechanisms substantially as and for the purpose herein set forthi
and illustrated.
6° A moveable furnace bridge constructed in accordance with one or a combination
of the above claims substantially as herein set forth and illustrated in the accom-
panying drawings. .
Dated this 21st day of June 1898
J. CLARK JEFFERSON,
2, East Parade, Leeds, Agent for Applicants.