Improvements in or relating to Furnace Fire Bars.
Year: 1895

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c., Act, 1883), as allowed: by
the decision of the Chief Examiner of the 24th day of September 1896.
Date of Application, 11th July, 1895
Complete Specification Left, 2nd Sept., 1895-Accepted, 14th Sept., 1895
PROVISIONAL SPECIFICATION.
Improvements in or relating to Furnace Fire Bars.
We, WILLIAM GODFREY GREGORY, of 54 Canal Street, Lace Manufacturer
and ANDREW PILLATT, of 2 Notintone Place, Sneinton, Mechanical Engineer
both in the Town and County of Nottingham, do hereby declare the nature of this
invention to be as follows:-
This invention has reference to improvements in or relating to furnace fire bars,
the main objects being to increase the efficiency of combustion of the furnace gases,
and also to provide for the bars being kept cool, thereby preventing them becoming
warped and destroyed under the heat of the fire.
For the purpose of our invention we employ hollow furnace bars open at both
ends and provided with lateral openings or air inlets. These bars are so arranged
in the furnace that a current of air will be induced through them by the natural
or other draught employed, the entrance of such air being facilitated by the said
inlets or openings. These latter may advantageously be situated on either side of
the bar near the lower edge thereof and their area is proportioned or regulated
according to the area of the bore or hollow of the furnace bar. Cool air being
admitted by the said air inlets as well as by the orifices or openings at the ends of
the bars, a sufficiently large volume of air is obtained and comes into contact with
the bars throughout their length and keeps them cool and prevents warping or
bending under the heat of the fire.
The arrangement of the bars in the furnace is such that the air is drawn
through them towards the fire bridge where it meets and mixes with the gases and
flame from the fuel. The efficiency of combustion of the fuel gases is thus
increased, since the air which has passed through the bars has become heated and
is thereby in a very suitable condition for effecting such combustion.
The bars may be made of any length and dimensions and when two or more bars
are placed end to end lengthwise of the grate, they may be so shaped at their
adjacent ends that they will fit one into the other and if desired form a practically
air-tight joint above the bearer bars or supports.
The air inlets are preferably of wedge or taper form and an equal number may
be arranged on each side of the rib of the fire bar.
Our invention can be applied to existing Lancashire boilers without drilling or
interfering with the furnace tube in any way, a bridge being suitably supported
without altering any of the arrangements of the furnace.

page_text: .
By the use of our invention there is a great saving in coal as the whole of the
fuel is used for the production of heat, and little or no smoke issues from the
chimney even when fresh fuel is thrown onto the fire.
Dated this 11th day of July 1895
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, and 5*, Market Street, Nottingham,
Agent for the Applicants.
Improvements in or relating to Furnace Fire Bars.
We, WILLIAM GODFREY GREGORY, of 54 Canal Street, Lace Manufacturer,
and ANDREW PILLATT, of 2. Notintone Place, Sneinton, Mechanical Engineer,
both in the Town and County of Nottingham, 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, reference being had
to the accompanying drawings and to the letters and figures marked thereon, that
is to say:-
This invention has reference to improvements in or relating to furnace fire bars,
the main object being to increase the efficiency of combustion of the furnace
gases.
For the purpose of our invention we employ hollow furnace bars, open at both
ends, and provided with a series of openings or air inlets at the sides or bottom of the
bars. These bars are so arranged in the furnace that a current of air will be induced
through them by the natural, or other, draught employed, the entrance of such air
being facilitated by the said inlets or openings. These latter may advantageously
be situated on each side of the bar, or of the web or rib of the bar, preferably near
the lower edge thereof, and their area is proportioned or regulated according to
the area of the bore or hollow of the furnace bar. Hot air being admitted by the
said air inlets from the ashpit, as well as by the orifices or openings at the ends of
the bars, a sufficiently large volume of air is obtained and comes into contact with
the inside of the bars throughout their length, keeps them comparatively cool, and
prevents warping or bending under the heat of the fire, and also has a sufficiently
high velocity to prevent the hollow of the bar from becoming choked, and having a
high temperature ensures perfect combustion of the fuel gases.
The arrangement of the bars in the furnace is such that the heated air is drawn
from between the bars and from the ash pit and passes through the hollow bars
towards the fire bridge, behind which it meets and mixes with the gases and flame
from the fuel. The efficiency of combustion of the fuel gases is thus increased,
since the air which has passed through the bars has a high temperature and is
therefore in a very suitable condition for effecting such combustion.
The bars may be made of any length and dimensions, and when two or more bars
are placed end to end lengthwise of the grate they may be so shaped at their
adjacent ends that they will fit one into the other, and if desired form a practically
air-tight joint above the bearer-bars or supports.
The air inlets are preferably of wedge or taper form, and an equal number may
be arranged on each side of the rib or web of the fire bar.
Our invention can be applied to existing Lancashire boilers without drilling or
interfering with the furnace tube in any way, a bridge being suitably supported
without altering any of the arrangements of the furnace.
By the use of our invention there is a great saving in coal, as the whole of the
fuel is used for the production of heat, and little or no smoke issues from the
chimney, even when fresh fuel is thrown on to the fire.

page_text: And in order that our invention may be readily understood, we will describe the
same fully with reference to the accompanying drawings, in which:
Fig. 1 is a sectional view of one form of fire bar constructed according to our
invention, and shows its position or arrangement in the furnace of a Lancashire or
like boiler.
Fig. 2 shows a modified form of bar applied to the furnace of a locomotive or
like boiler.
Figs. 3, 4, and 5 show in plan, elevation, and cross section, respectively, a form of
construction of our improved fire bar applicable to Lancashire,marine, Fairbairn,
elephant, and other steam boilers, two of such bars being shown arranged side by
side in Fig. 3.
Figs.
to 10 show various modified cross sections of furnace or fire bars applicable
to all kinds of boilers, or to the furnaces of kilns, and other heating apparatus.
Figs. 11 and 12 show, in longitudinal section and end view, respectively, a
modified form of fire bar applicable to small furnaces or grates, such as vertical
boiler grates, having no bridge.
Fig. 13 shows in elevation a modified form of bar with inclined air inlets; and
Figs. 14 and 15 show mid sections of a modification of our invention applicable to
small marine boilers, or to other purposes. The long slot shewn in Fig. 15 is
equivalent to a series of openings such as above referred to.
Our improved fire bar is formed with a passage a from end to end, and has
a series of perforations, openings, or air inlets a', arranged at intervals along. it.
a² are the bearer bars or supports for the fire bars. b is the mouth of the passage a,
which may be modified in shape according to the design of the furnace to which the
bars are to be applied. For instance, the hollow bar may terminate at the front
with an enlarged open mouth 6 (see Fig. 1); or the mouth may be of the same
area as the passage through the bar, and open downwards (as in Fig. 2). The back
or bridge end of the fire bars for Lancashire boilers, or other boilers having a
similar bridge c (Fig. 1), is so shaped as to fit or rest upon the support d under
the bridge. But in the case of locomotive and like boilers (Fig. 2), the bar
presents an upward opening a*, the bridge c being formed at the back with an
opening e, or a series of openings, of any convenient form. A wall, preferably
of fire brick or clay, is held in position by projections 9 on the fire bars, and forms
a chamber or air space h, at the back of the fire. In both of these arrangements the
air is drawn through the series of perforations, openings, or air inlets a¹, and passage a
of the fire bars, in the direction indicated by the arrows, and meets the flame and
fuel gases pouring over the bridge, and so effects their enhanced combustion,
without smoke. By this means all the fuel gases are consumed, and a long sheet
of flame is caused to shoot the whole length of the furnace, thus producing a very
quick generation of steam.
For
The air inlets a' may be of any desired shape, and be located in any convenient
position underneath or at the side of the fire bar, so that they shall not be liable
to choke up; their area being determined by the character of the fuel.
ordinary furnace coal, the combined area of all the inlets in a bar would be
approximately equal to the area of the passage through the bar.
The air inlets are preferably of taper or wedge shape, as shown in Fig. 1, and
are arranged in equal numbers in each side of the bar.
In some cases, the bars may be provided with tail pieces; (see Figs. 11 and 12)
for carrying the heated air from the ashpit, or from beneath the fire, to the level
of the top of the fire at the back.
In Fig. 13 the air inlets are shown inclined towards the bridge end of the fire
bars, and in Fig. 15 a single air inlet or slot extending the whole length of the web
of the bar is shown.
It is obvious that fire bars constructed according to our invention can be
variously modified in shape, without departing from the nature of such invention.
We are aware that hollow fire bars which permitted the air to pass through them
to the back of the furnace have been proposed and in some cases an additional orifice
"

page_text: has been provided other than the front end of the bar to admit the air. Such
arrangements have in practice however failed and cannot accomplish that which we
obtain by our invention the essential features of which are hollow fire bars open at.
both ends and provided with a series of openings along their sides or bottom sufficient
to allow the heated air to enter freely from the space between and immediately under
the bars and be carried onward to the back of the fire bridge in such a condition as
materially to aid the combustion of the fuel gases.
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. The construction of hollow fire bars open at both ends and provided with a
series of perforations, openings, or air inlets, arranged at intervals along the sides
or bottom of the same, substantially as described, and for the purposes set forth.
2. The construction and arrangement of hollow fire bar as described and shown
with reference to Fig. 1 of the drawings.
3. The construction and arrangement of hollow fire bar, as described and shown
with reference to Fig. 2 of the drawings.
4. The construction of hollow fire bar as described and shown with reference to
Figs. 3, 4, and 5 of the drawings, or having its cross section modified according to
any of the forms shown in Figs. 6 to 10, and 14 and 15.
.
5. The modified form of hollow fire bar, as described and shown with reference
to Figs. 11 and 12 of the drawings.
6. The construction of hollow fire bar in which the air inlets are inclined towards
the fire bridge, as described and shown with reference to Fig. 13 of the drawings.
7. Our improvements in or relating to hollow fire bars, substantially as herein-
before described and as shown in the annexed drawings, whereby the efficiency of
combustion of the furnace gases is increased.
Dated this 2nd dor of Sentember 1805
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, and 5ª Market Street, Nottingham,
Agent for the Applicants.