IMPROVEMENTS IN FURNACE BARS AND FIRE GRATES
Year: 1883

page_text: 1
LETTERS PATENT to George Lamb Scott of Manchester in the County of
Lancaster Engineer for an Invention of "IMPROVEMENTS IN FURNACE BARS
AND FIRE GRATES
33
PROVISIONAL SPECIFICATION left by the said George Lamb Scott at the
Office of the Commissioners of Patents on the 10th April 1883.
_GEORGE LAMB SCOTT of Manchester in the County of Lancaster, Engineer,'
"IMPROVEMENTS IN FURNACE BARS AND FIRE GRATES
"
My Invention relates to the bars and grates of steam generator and other furnaces*
and fire places and consists of arrangements for preventing the bars from becoming
distorted or destroyed by heat and also to render the said bars or their parts more
easily and economically replaced than hitherto. Furnace bars made in accordance
with my invention are of a composite construction the upper parts in contact with
the fuel being made removable. The said upper parts are cast in short lengths and
are preferably made of a harder metal than the lower part of the bar so as more
easily to resist the destructive effects of the heat. In some cases the said top parts
might be made of fire clay. The lower part of the bar is cast or formed with
shugs or projections upon which the removable parts rest, the spaces between the
said snugs allowing free circulation of air among the bars thereby increasing the
smoke consuming powers of the grate. The said removable tops may be applied
to furnace bars arranged singly in the ordinary manner but I prefer to construct
then as double bars and to form the top lengths with air spaces or interstices. The
said top pieces are formed with toes or projections which bear against the sides of
the supporting snugs on the bar and prevent lateral movement and their ends abut
upon one another so as to prevent their moving lengthwise sufficient clearance
being allowed for expansion and contraction. When any one of the top parts has
become damaged it is only necessary to remove the injured member and replace it
by a fresh one instead of having to replace the whole bar as heretofore. I also
arrange for a mechanical vibration of the bars constituting my invention. The .

page_text: bars rest at each end upon cross bearing bars and are connected together by studs
or links so that when a lateral vibrating motion is communicated to one bar of the
series the other bars are correspondingly moved which has the effect of clearing the
air spaces, promoting combustion and preventing the formation of clinkers. The
bearing bars may rest upon friction bowls carried by the dead plate and bridge and 5
the motion may be communicated manually or automatically by a rack and pinion,
wiper and shaft or other suitable means.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Lamb Scott in the Great Seal Patent Office on the
16th October 1883.
GEORGE LAMB SCOTT of Manchester in the County of Lancaster, Engineer,
"IMPROVEMENTS IN FURNACE BARS AND FIRE GRATES
"
My Invention relates to the bars and grates of steam generator and other furnaces
and fire places and consists of arrangements for preventing the bars from becoming
distorted or destroyed by heat and also for rendering the said bars or their parts
capable of being more easily and economically replaced than hitherto. Furnace
bars made in accordance with my Invention are of a composite construction the
upper parts in contact with the fuel being removable. The said upper parts are
cast in short lengths or sections so that when any one of the top parts or sections
has become damaged it is only necessary to remove the injured part and replace it
by a fresh one instead of having to replace the whole bar as heretofore. I also
arrange for a mechanical vibration of the bars constituting my Invention. The
bars rest at each end upon cross bearing bars and are connected together so that
when a lateral vibrating motion is communicated to one bar of the series the other
bars are corresponding moved which has the effect of clearing the air spaces
promoting combustion and preventing the formation of clinkers.
In order that my Invention may be fully understood I have attached hereto a
sheet of drawings made to a scale of about one and three quarter inches to the foot.
In the said drawings Fig 1 represents a vertical section and Fig 2 a cross section of
a boiler furnace flue fitted with my improved grate which appears in plan in Fig 3.
In the said Figs. a, a, are bearer bars which sustain the sections b, b, upon which
the fuel rests. In the example the sections forming the grate surface are sustained
by four bearer bars which are cast in pairs the two in each pair being connected
in the casting by cross bars so that the twelve sections forming the grate are
sustained by the two castings. On the upper faces of the bars a are formed ridges
on which the ends of the grate sections rest so that spaces c are left for the passage
of air between the grate and the bearer bars whereby overheating of the latter is
prevented. On the two inner bars these ridges project beyond the bar in a direction
towards the centre of the furnace as indicated by d, d, in Fig 2. These projections
sustain the centre row of sections. Each section is formed with snugs on its lower

page_text: surface these snugs entering between the bearer bars and keeping the section in
position sideways. The ends of the sections abut together whereby the sections
are kept from moving out of position in a lengthwise direction clearances to allow
for expansion and to permit the passage of air being provided. The sections may
each consist of a cluster of bars cast together so as to form a small grate the
number of bars being less or more than as indicated in the drawings or the
sections may be otherwise suitably formed with interstices for the passage of air.
It will be seen that the lower bearer bars being shielded from the excessive heat
are not so liable to be damaged as in the case of ordinary fire bars and will last a
long time. The upper sections are preferably made of a harder iron than the bearer
bars and as each section is small it can be made very thin and light as compared
with ordinary bars and the surfaces in contact with the fire being narrow and the
air passages numerous the sections are not so liable to burn or to become distorted.
Any section which may become unfit for use can be quickly removed and a new
section be dropped in it's place such renewals being effected at a small cost owing
to the lightness of each section. In some cases I may make the sections of fire clay
or of a suitable refractory material. In the example the two pairs of bars a, a, are
mounted to slide upon bearers e, e, and are connected at each end by means of
racks, ff, with which gear rack pinions which are upon a shaft g The bearers a, a,
may if desired be provided with friction bowls. The said shaft is fitted to rock in
bearings and is provided at the front end of the furnace with a hand lever h.
When the said shaft is rocked by means of the lever the bearer bars a, a, are caused
to move to and fro sideways carrying with them the whole of the grate surface to
which a shaking movement is imparted which has the effect of clearing the air
spaces as hereinbefore mentioned. Stops are provided to limit the traverse and to
jog the grate at the end of each movement. To permit of this sideway shaking or
movement of the grate surfaces spaces have to be left between the outermost
sections and the shell of the flue. To cover these spaces bars i, formed with
teeth which project slightly over the sides of the grate are fixed to the flue or
furnace sides. Fig 4 illustrates a modification-wherein the upper surfaces of the
bars i, i are level with the general grate surface. In this example the outer side
of the outside sections are formed with teeth which interlock with teeth on the
said bars the length of the teeth being made sufficient to provide for the sido
movement of the grate. I do not confine myself to the casting together of the
bearer bars & in pairs nor to the number of the bearer bars employed to sustain
cach grate nor to the precise method of keeping the sections in position or of fitting
them on the bearer bars nor do I confine myself to the number of the sections
forming each grate nor to the method of producing the shaking motion. In the
modifications illustrate by Figs 5 and 6 single bearer bars are used. Each section
is cast with two snugs which are at about the centre of the width of the section
and these snugs enter recesses cast in the bearer bar and are secured therein by
means of pins or bolts. Any other suitable method of mounting the sections upon
the bar may be adopted. The bars receive a shaking motion from reciprocating
racks for from a single rack which may be actuated as hereinbefore described.
Instead of being shaken laterally as hereinbefore described the bars may be
reciprocated lengthwise. My Invention is also capable of applicable [sic] to the
bars used in mechanical stoking apparatus.
Having now fully set forth and indicated the nature of my said Invention and
the manner in which I carry the same into practical effect I would have it to be
understood that I claim:-
First. The combination of parts forming the fire grate for use in steam generator
or other furnaces substantially as set forth and indicated hereinbefore and in and by
the accompanying drawings.
Secondly. In a furnace grate constructing the grate in comparatively short and
small sections which are carried by the main bars which are not in contact with the
mass of fuel so that any section may be readily renewed without having to renew
any of the bars substantially as set forth and indicated.

page_text: And lastly. The method of and arrangements for shaking or vibrating a furnace
grate substantially as set forth and indicated.
In witness whereof I George Lamb Scott have hereunto set my hand and
seal this fifteenth day of October in the year of our Lord one thousand eight
hundred and eighty-three
Signed, sealed and delivered
in the presence of
EDWARD K. DUTTON
41 John Dalton St, Manchester
GEORGE. L. SCOTT (L.S.)