Improvements in Furnace Bars and Grates for the Better Consumption of Fuel and Smoke.
Year: 1890

page_text: Date of Application, 14th Apr., 1890
Complete Specification Left, 14th Jan., 1891-Accepted, 14th Apr., 1891
PROVISIONAL SPECIFICATION.
Improvements in Furnace Bars and Grates for the Better
Consumption of Fuel and Smoke.
WILLIAM FRASER, Engineer, "Glenholme," Anderton Road, Sparkbrook,
Birmingham, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to manufacture hollow-furnace bars for boiler
furnaces, muffles and the like and also for the purpose of supplying the said
furnaces with the necessary oxygen to ensure perfect combustion at as high a
temperature as possible. To obtain these results instead of casting the furnace bars
in the ordinary way, or with a.tube or core hole through them I make the bar either
out of sheet steel, or sheet iron, or any other suitable material, and then have the
top part of them cast either in cast iron chilled or otherwise, or malleable, i.e., the
top part of the bar would simply be cast about 11" or thereby deep the bottom part
having a recess on both sides about ", and about 4" deep i.e., the top part of the
casting would be say 1" or thereby broad and 3" deep the bottom portion being
3" broad and " deep, this portion fits into or slips in between the two upright sheet
steel sides, the extra " on each side of the top or uppermost portion forming a
support or rest for same, thus one half of the depth of the casting stands above the
sheet steel sides and rests right on the top of same, the other half dropping in
between the two upright sides. The object in having the bar in two separate parts,
is, the sheet steel has the advantage of strength and lightness combined, and supplies
a larger area through the bar, for the admission of air to the furnace, and then the
top part can be removed any time when destroyed by the fire thus, a new top can
be dropped on to the fire bar when required by simply knocking the burned top of
the bar out and dropping in a new top which is not the fourth part of the weight of
an ordinary furnace bar. The sides of the bar are made simply by doubling up say
a 8" strip of sheet steel about " or thereby thick and leaving the two sides about "
or thereby apart thus, the bar would be say, about 4" or thereby deep with a "
oblong hole about 34" deep right through it, the cast piece on the top adding another
3" to it, i.e., when finished it would be 1" x 42" with a 3" x 31 oblong hole right
through same. It is obvious that with a furnace bar with so large an area or air
way through it as this, that there would be an ample supply of air got to any
ordinary furnace by causing the furnace to draw the supply right through the said
fire bars and discharge direct into the ashpit. Of course to get this result the
ashpit would require to be fitted with a close fitting door to prevent the air from
getting below the bars, by this arrangement the furnace would pull all the air
required right through the hollow bars, thus increasing the temperature of the air
in its transit to the furnace and by so doing keeping down the temperature of the
bars and preventing same from burning. Another part of this invention is in
casting a hollow furnace bar to leave its own core in the sand i.e., suppose the bar to
be 1" broad and 4" deep it could be recessed from the bottom side about 3" wide and
3" deep leaving about 1" of metal on the top of the bar with two thin sides
about 3" deep and about or thereby thick with the air drawn through these bars
the way already mentioned, it can be distributed in various ways to the fuel, part of
it to the bottom grate, part of it to the sides of the furnace, and part of it to the
bridge and top of the fuel; but what I particularly wish to mention is in having a
furnace bar made in separate parts for the purpose of removing the burned or
destroyed part at will, and for the purpose of increasing the area for supplying the
air, and in using sheet steel and sheet iron for the manufacture of same.

page_text: COMPLETE SPECIFICATION.
Improvements in Furnace Bars and Grates for the Better
Consumption of Fuel and Smoke.
WILLIAM FRASER, Engineer, 99, Anderton Road, Sparkbrook, Birmingham,
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 this invention is to manufacture hollow furnace bars for boiler
furnaces, muffles and the like, and also for the purpose of supplying the said furnaces
with the necessary oxygen to ensure perfect combustion at as high a temperature as
possible. To obtain these results; instead of casting the furnace bars in the ordinary
way, or with a tube or hole cored through them, I make the lower part of the
bar either out of sheet steel or sheet iron or other suitable metal, and cast the upper
part separately by preference in a chilled mould-in cast iron or steel, or chilled
or malleable iron. That is, I cast the top portion of the bar, which comes in direct
contact with the burning fuel, separately, and fit it into or slip it on the lower or
bottom part of the bar which is formed by bent or moulded sheet steel or iron in a
trough form, suitably held together by rivets or otherwise. One part of the cast
portion stands above the trough sides and another part projects between them.
The compound bar so formed has many advantages among which are the following:-
A larger area through the bar is allowed for the passage of air than is possible with
ordinary hollow fire bars. The compound bar is lighter and stronger than ordinary
fire bars. The upper part can be removed at any time when destroyed by the fire
and replaced by a new casting, and a considerable weight of metal is thereby saved
as the top is very much higher than an ordinary fire bar. The area through the
hollow of my compound fire bar is made so large, that the whole of the air supply
of the furnace may be taken through the bars by suitably arranging the ash pit and
air connections. The air is thus heated before coming into contact with the fuel
and the fire bars are cooled so as to greatly prolong their effective life.
In constructing a brick-built furnace according to my invention, the ashpit is
provided with close fitting doors to completely prevent the access of air to said pit,
and the air required for combustion is all drawn through the deadplate and hollow
bars, the said deadplate being hollow and the apertures therethrough of sufficient
area to supply the necessary volume of air. The furnace bars are supported by the
hollow deadplate, hollow bearers, and bridge. The latter can be constructed in
brick, but I prefer to use a hollow metal shell, and to face or line the parts exposed
to the direct action of the fire with fire clay brick.
The said hollow bridge is divided into two chambers (back and front) by a
division plate placed about the middle of the chamber and rising to within a few
inches of the crown or top of same, for the purpose of causing the air to ascend or
travel up one side of the chamber, and down the other the object being to increase
the temperature of same as much as possible in its transit from the deadplate to the
fuel. By this arrangement all the air required for combustion is drawn first,
through the hollow deadplate, then the hollow fire bars, and then into the hollow
bridge. It then ascends to the top or crown of the front chamber and then descends
to the bottom of the other, and ultimately passes into the ash pit at a very high
temperature.
The air can be still further heated by being conveyed from the bridge to the front
end of the ash pit instead of being discharged into same at the bridge.
To accomplish this the air would be discharged from the bridge direct into
channels built in the brickwork at each side and conveyed by same to the front end
of the ash pit, where the air would be discharged at a very high temperature. The
said air channels would be constructed immediately behind the lining brickwork of
the furnace where the heat is most intense, and connected with suitable channels to
and from the bridge and ashpit respectively. The heated air is then divided into

page_text: four distinct quantities viz., one for the centre of the grate, one for the bridge and
one for each side of the furnace. The two side outlets are governed by regulators
to deliver and regulate the supply of air to the top of the fuel, and a damper or
regulator is fitted in the bridge to control the supply of air behind the bridge.
The regulators for the two sides control the centre current of air as well as the two
side currents, by hanging them down several inches below the level of the fire bars,
and by running them from one end of the ashpit to the other; and they thereby
divide the ashpit into three different sections, the supply of air for the middle of the
grate being determined by the depth of the side regulators.
Thus, the bottom or underside of the fuel is supplied with the required quantity
of air by the centre or middle current, the top of the fuel draws its supply from the
two side currents, and the gases that pass the bridge take their supply through the
bridge. By this arrangement the air required for combustion is supplied at an
extremely high temperature, either above or below the fuel, or at the back of the
bridge, and by this means the requirements of any furnace at present in use may be
complied with and perfect combustion ensured and great economy in fuel effected.
It is obvious that the same arrangement slightly modified can be adopted to all
kinds of steam boilers and furnaces, muffles, and the like, and that the construction
of the grate can be altered from that of a straight or flat grate to that of a curved
or convex one, which would be most suitable and serviceable for Lancashire and
Cornish boilers.
By dropping the sides of the grate the heating surface is considerably increased
and the centre of the grate still remains about the same distance from the crown of
the tube, as with the flat grates at present in use.
It will also be observed that the various improvements mentioned can be used in
any combination or separately and arranged and constructed in different forms..
will now proceed to describe the various figures of the accompanying drawings.
Figure I represents in vertical section partly in elevation, a steam boiler and
furnace grate with side air diffusers, regulators, rods, handles and connecting brackets,
also the air channels in the brickwork for conveying the heated air from the bridge
along the sides of the furnace to the ashpit; and Figure 2 is a plan of same.
In these figures a is the boiler; b is the furnace. c are the air diffusers; d are
the air regulators; e are the regulating rods; fare the handles thereof; 9 are the
brackets for supporting the rods; and (shown in dotted lines in Figure 1)
represents the air channels in the brickwork of the furnace; and h¹ are the small
channels for conveying the heated air from / to the ash pit. are the connecting
channels between the bridge and the two main channels h. i is the ash pit; f' is a
bolt for fastening the supporting plate 2 of the regulator rods e to the brickwork
of the furnace. (Figure 2) is the furnace grate consisting of fire bars herein
described, & being the hollow deadplate. In Figure 3, which is a front view of
furnace front, the hollow dead plate and ashpit doors are shown, k being the upper
part, and ¹ the lower part thereof; and between these plates the ends of the
hollow bars j are seen. are the doors for closing the ashpit, and f the handles of
the air regulator rods e.
Figure IV illustrates in elevation a hollow bearer for supporting the furnace.
The bearers are designated m, and the pieces which I call distance pieces, are
marked m¹. These can be made wider, or narrower for the
purpose of lengthening
or shortening the said bearer and suiting different widths of furnaces.
Figure V is a plan or view of the upper or top side of Figure IV, and represents
either of the end bar bearers of a furnace; and
Figure VI is a longitudinal section through the grate, bar bearer, and hollow
bridge. The middle bar bearer m, is scolloped or recessed on both sides for the
purpose of receiving and supporting the ends of a set of fire bars j on each
side of it (see Figure VI). The hollow bridge is generally designated n and n' is
the division plate dividing the interior chamber thereof into two compartments n²
and . n is the back plate, the top part of which is perforated (see Figures VI
and VIA) for allowing part of the heated air to be distributed behind the bridge.

page_text: n is a door at the bottom for the purpose of removing soot and other matters; and
n and n are damper doors.
Figure VII is a section shewing a modification of bridge fitted with a regulating
perforated damper n³ and a rod and bell crank lever n for working same, and by
which the quantity of air required to pass through the bridge back plate n' is
controlled.
is
Figures VIII and IX shew in side elevation and cross section, respectively, the
compound hollow bar. j' is the upper removable cast part of the bar, and
the bottom, this being made preferably of sheet steel. are rivets or pins which
keep the hollow part together and by which the top and bottom parts are fastened
or secured together. is a back bone of the top or cast part of the bar, and is
by preference made of sheet steel or malleable iron cast in the bar. Slots or gaps
marked are provided in and at the top it has turned over parts 7. This
plate is cut to the proper length before being laid in the mould, and the metal
run round it; by so doing all machine work is avoided. The top part by
having its back bone made of sheet metal is much lighter and stronger than if it
were made in cast iron; but if made of cast iron it would be a modification of the
other, and may be so made if desired. It will be observed that the upper edges of
the sheet metal lower part 3 enters and lies in recesses or grooves in the top
part of the bar, thus both parts expand and contract together thus also dust is
prevented from falling into the lower hollow part 3 of the bar.
The air required for combustion is all introduced through the hollow dead
plate and the fire bars marked j, and is discharged into the hollow bridge n.
From here it is conveyed by the two channels / into the main channels marked h;
and from these it passes by way of the small outlets into the ash pit below the
furnace grate. By turning the regulating handles of the regulating valves d the
supply of air through the sides of the furnace above the fuel may be regulated. The
rim of the handles fand the plate f2 are both notched or serrated in their faces,
and the former is fitted with a spiral spring f (see Figure XVII) and collar to
cause the serrations or notches of its rim, to press upon and gear with those of
the plates 2; thus by these means the regulators d can be opened or closed to any
extent required, and upon releasing the handle after regulating they engage with
the plate the regulating valves d remain in that position locked. The air which
enters the hollow bridge n is, as previously stated, conveyed thereto by way of the
hollow dead plate and hollow bars j. It first enters the chamber n² of the bridge
and ascends up same on one side of the plate n', and then descends on the other
side thereof within the back chamber n³. The heated air from here either passes
into the side channels (Figures I and II) or partly through the back perforated
plate n of the bridge shewn in Figures VI and VIA; or it may be distributed by
all the different outlets mentioned, or in any particular way desired. By this
invention the temperature of the air used to burn the fuel is increased to such an
extent by travelling through the bars, then the bridge, and side channels in the
brick-work, that complete combustion is obtained; and the life of the furnace
bars furnace linings bridge and fittings is by the air also very considerably
prolonged.
Figure X is a plan of a grate constructed according to my invention suitable for
.a Lancashire or Cornish boiler, and
Figure X is a cross section of same.
Figure XIII shews the interior of a grate fitted in a furnace or tube and
Figure XII is a longitudinal sectional elevation of the grate shown in
Figure X.
Figure XI shews the framework of the grate.
With reference to these figures c¹ are the longitudinal bearers for supporting the
air diffusers c, and el are stay rods which pass through all the bearers m and
keep the grate together, whilst e are the regulator rods for working the air
regulators d.
Figure XIV is an end view of Figures X and XI.

page_text: The plates in this arrangement are adjustable vertically, and can be raised or
lowered to any extent. The tails of said plates pass through apertures fƒ³ in the
front bearer m. The bearer marked j¹ shews the openings for the air to pass
through the dead plate & subsequently the bars.
Figure XVI shews a curved fire-bar bearer, having at each end clamps m
consisting of toothed plates bolted onto the bearers as shown, the bearers having
slotted holes through which the fastening bolts pass for the purpose of enabling
the clamps to be fixed where desired. By these means the bearers m can be
lengthening or adjusting as desired. In fitting a Lancashire or Cornish boiler the
bearers m, if so desired, may be supported by the walls of the tube in the ordinary
way, and in such a case the arrangement shewn in Figure XVI for shortening or
lengthening the bearer is of great service, in that one is able to effect a proper
bearing in the tubes, even in those in which lap joints occur.
The ash pit marked in Figures XIII and XIV if hollow bars are used would
be fitted with close fitting doors, as above specified, and all the air required for the
grate would be introduced through the bars and dead plate, and discharged into
the bridge, as set forth with reference to Figure VII, the air being then discharged
therefrom into the ash pit, and part of it behind the bridge as already described
and set forth. The air diffusers c (shewn in section in Figure X^) can be made
to rest upon the bearer bars e; or they may be made to rest upon ordinary fire
bars as shewn in Figure X³. In cases in which the furnace is a tube the diffusers
would be curved at their backs to fit the curved surface of the tube, but for a brick
built grate they would be made as shewn in Figure XC and with lugs cast on their
underside for supporting the regulator rods e.
If the air diffusers are supported
upon the grate bars the bearers c¹ would be dispensed with. The said diffusers
can be made in sections of any length or height required and the air orifices made
any size or dimensions.
The object in having the grate in curved form and as low as possible as shown
in Figures XIII and XIV is for the purpose of increasing the heating surface in
the furnace, that is the part above the grate, the best results being got by arranging-
the top of the air diffusers below the centre line of the furnace, as shewn in
Figure XIII.
The said grate with air diffusers can be filled with solid trebble bars as shewn in
Figure X instead of with my compound bar but I would prefer the former.
The dead plate bearer in this class of boilers may be straight at the door and
gradually take the curve required about 18" or thereabouts along the grate.
Figure XD shews the brackets g for connecting the regulators d to the rods e,
said rods and brackets having a flat side g¹ upon them.
Having now described and ascertained the nature of my said invention, and in
what manner the same is to be performed, I declare that what I claim is :-
First. A brick built or other furnace constructed with air channels at the sides
or in the lining of the furnace for conveying air from the bridge to the ashpit
below the furnace grate substantially as set forth with reference to the drawings.
Second. Regulating the air delivered to furnaces by means of rods regulators
and fittings, substantially as set forth with reference to Figures I II III X XI
XII XIII XIV XV and XVII of the drawings.
Third. Conveying the air used to burn the fuel in a furnace through a hollow
dead plate and hollow fuel bearers or bars and then delivering it to the fuel for the
purpose set forth.
Fourth. In a furnace a hollow bridge constructed as set forth with reference to
Figures VI and VII for the purpose set forth.
Fifth. A furnace bar consisting of two parts substantially as set forth.
Sixth. In a furnace, air diffusers substantially as set forth with reference to
Figures III III X X X X XII and XIII for the purpose of distributing the
air above the fuel.

page_text: Seventh. In a furnace, bar bearers (m) as set forth with reference to
Figures IV V and XVI in particular for the purpose of adjusting.
Eighth. The bearer m set forth with reference to Figure XIV having holes
therein, in combination with the adjustable hanging brackets for the adjustment
of the rods specified.
Ninth. In a furnace a fire grate provided with one or more of the herein
described improvements; or, a grate constructed or provided with my improvements
whereby perfect combustion of fuel is effected and the steam generating power of a
boiler increased.
Dated l
C
1001
WILLIAM FRASER.