IMPROVEMENTS IN STEAM BOILERS, FURNACES, AND FIRE BARS
Year: 1856

page_text: LETTERS PATENT to John Gray, of Peckham, in the County of Surrey,
Engineer, for the Invention of "IMPROVEMENTS IN STEAM BOILERS, FURNACES,
AND FIRE BARS."
Sealed the 29th July 1856, and dated the 1st April 1856.
PROVISIONAL SPECIFICATION left by the said John Gray at the Office
of the Commissioners of Patents, with his Petition, on the 1st April
1856.
I, JOHN GRAY, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM BOILERS, FURNACES, AND FIRE BARS," to be as
follows:-
I construct steam boilers in which the flame or products of combustion from
the furnace are conducted through a series of tubes, as in ordinary locomotive
and marine boilers, but I construct the tubes with a series of chambers of
spherical or other suitable form on their upper surfaces. The products of
combustion enter these chambers, and communicate their heat to the water in
the boiler which surrounds them, in lieu of passing straight through the tubes
and away to the chimney. In the smoke box I place a vessel for heating the
feed water for the boiler; the water enters through a valve and passes from
the upper part of the vessel into the boiler. The tubes and the chambers may
be about six inches diameter, more or less, and they may be cast upon the
tubes, or brazed or rivetted, or otherwise attached to them. The tubes may be
made in two or more lengths, for convenience in introducing and removing

page_text: them, and they may be of brass or iron, or other suitable material. In lieu of
building the sides of the furnaces of brickwork, which requires to be pulled
down when worn out and rebuilt, I build into the brickwork an iron frame on
cach side of the furnace, into which frame I slide a loose solid or hollow block
or blocks of iron, or of fire brick, or both; when these are worn out, I draw
them out of the frame and I slide in other new blocks without having to
disturb the masonry or brickwork of the furnace. A small quantity of air may
be allowed to pass behind or through perforations in the blocks. When one
side of a block is worn out it may be turned, so as to present the other side
to the fire, and if it be worn or burnt more at one end than the other it may
be turned end for end. The bridge of the furnace may be of the ordinary
construction, or it may be made with a series of slots or deep notches, so as to
allow a portion of the flame to pass through the bridge while the rest passes
over it. The furnace bars are made with diagonal grooves across their upper
surfaces; these grooves admit an increased quantity of air to the fuel, while
their diagonal direction prevents them from interfering with the passage of a
rake or scraper over them; the bottoms of the grooves are inclined to faci-
Jitate the descent of the dust and ashes. The ends. of the fire bars next the
bridge are turned up at an angle of forty-five degrees, more or less, and for
a height of six or eight inches, more or less; they are provided with distance
pieces to keep them at regular distances apart. Air enters through these in-
clined portions of the bars, and effects the combustion of the smoke, or pre-
vents the formation of smoke. For burning anthracite coal and coke, the bars
with the diagonal grooves may be employed without the inclined portion next
the bridge. These furnace bars and the moveable side blocks, hercin-before
mentioned, are applicable to steam boiler furnaces, and to the furnaces of bakers'
ovens, and to furnaces generally.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Gray in the Great Seal Patent Office on the
29th September 1856.
3
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
GRAY, of Peckham, in the County of Surrey, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of April, in the year of our Lord One
thousand eight hundred and fifty-six, in the nineteenth year of Her reign, 3

page_text: did, for Herself, Her heirs and successors, give and grant unto me, the
said John Gray, Her special licence that I, the said John Gray, my executors,
administrators, and assigns, or such others as I, the said John Gray, my
executors, administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN STEAM BOILERS,
FURNACES, AND FIRE BARS," upon the condition (amongst others) that I, the
said John Gray, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said John Gray, do hereby declare the nature
of the said Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement
thereof, reference being had to the accompanying Drawings, and to the figures
and letters marked thereon, that is to say:-
Figure 1, Sheet I, of the accompanying Drawings, is a longitudinal section
of a marine boiler constructed according to my Invention; Figure 2 is a
transverse section of the same; Figure 3 is an end view of the same, with the
door of the smoke box removed. The same letters indicate similar parts in
cach Figure.
A is the outer shell or body of the boiler; B, B, B, are the internal furnaces;
C, C, C, are the ash-pits; D, D, are the fire bars; E, E, E, are the bridges;
F is the back smoke box, which may connect the three furnaces, or each
furnace may have a separate smoke box F; G, G, are the tubes, with chambers
H, H, upon them; I is the front smoke box, communicating with the chimney
by the take-up K; J is the smoke box door; L is the furnace door; M, M, are
stays for strengthening the shell A.
Figure 4 is a longitudinal section of one of the tubes G, with its chambers
H, H. I construct these tubes of about six inches in diameter, more or less,
and in two or more lengths. In the upper surface of the tube apertures are
formed of four inches in diameter, or more or less; and over the said apertures
I affix chambers H, of a spherical or other convenient form, six inches in
diameter, or more or less, and with apertures corresponding to those in the
tube G. The tubes and chambers may be constructed of brass, copper, iron,.
:

page_text: or other suitable material. The chambers may be cast on the tubes, or rivetted
or brazed, or otherwise attached thereto. The ends of the tubes which com-
municate with the front smoke box I, or some of them, may be made smaller
than the other ends, or contracted by the insertion of ferules, so as to regulate
the velocity of the flame and products of combustion through them. The
tubes are made in two or more lengths, united by flanges and bolts and nuts, or
otherwise, so that they may be disconnected and taken out when required.
The chambers may be connected with each other and with the front smoke
box by small tubes, as shewn in the lower tier in Figure 1, so as to promote a
current through them; or they may communicate with the tube G only, as
shown in the upper tiers of tubes in Figure 1. As the flame and products of
combustion pass through the tubes, they rise into the chambers and com-
municate their heat to the water in the boiler, instead of passing in a rapid
undisturbed current through the straight tubes; the hot gases are thus more
efficiently compelled to give out their heat to the water.
same.
Figure 5 is a plan of a set of my improved fire bars D; Figure 6 is a side
view, and Figure 7 is a section, of one of my improved fire bars, drawn to a
larger scale; Figure 8 is a plan, and Figure 9 is a perspective view of the
The upper surface of each bar is a plane or flat surface, intersected by
a series of diagonal channels, as shewn in the plan, Figure 8. The bottoms
of these channels are inclined to one side, or from the centre to each side, so
as to allow the dust and ashes to fall. The diagonal position of the channels
allows of a rake or scraper being passed over them to arrange the fire, or to
rake out clinkers or ashes as may be required; the flat spaces between the
channels serve to support the fuel. By constructing the bars in this manner
a large additional area for the entrance of air is obtained, and the combustion
is rendered more perfect. The back ends d of the bars are inclined upwards,
and come in contact with or near to the bridge of the furnace, as shewn at E
in Figure 1. Streams of air ascend between the inclined parts d of the fire
bars, and also between those parts and the bridge E, when space is left there
for that purpose; these streams of air mix with the gases passing over the
bridge and complete their combustion. When, however, the fuel is of such a
nature as not to require this additional supply of air, or it is not required to
perfectly consume the smoke, the inclined part of the fire bar may be omitted,
as shewn in Figure 10. This construction of fire bar is applicable both for
fixed fire bars and for moveable fire bars, whether the motion be reciprocating
ór oscillatory or continuous, as when an endless chain of fire bars is used.
The width of the channels may be about three-eighths of an inch, or more
or less, according to the nature of the fuel to be employed. For very small

page_text: coal they may be made narrower, and for large coal or for coke they may be
made wider; the width of the flat portions of the bar between the channels
may also
vary. It is advantageous to make the channels wider at the bottom
than at the top. Thus, Figure 11 is a perspective view of a bar with wider
flat surfaces between the channels.. In this bar the channels are shewn wider
at the bottom than at the top; the escape of the dust and ashes is thus
facilitated.
Figure 12, Sheet II., is a longitudinal section of a furnace adapted for a
baker's oven; Figure 18 is a front view of the same; Figure 14 is a transverso
section of the same, with tho fire bars and side blocks removed. The same
letters indicate similar parts in each of these Figures. C is the ash-pit; D in
Figure 12 is one of the fire bars constructed with channels, like those herein-
before described; E is the bridge; L is the furnace door; O is the ash-pit
floor; P, P, are cast-iron frames, built into the brickwork Q of the furnace;
R, R, are blocks or cheeks of cast iron, which slide into the frames P, P, and
form the sides the furnace; S is the top of the furnace, on which may be
placed a boiler T for heating water; U is the body.of the oven. The blocks
or cheeks R, R, can be drawn out and replaced by others when they become
burnt or injured by use, or they may be turned over or turned end for end
when required; a great saving of time and labour in repairing brickwork is
thus effected. The blocks R, R, may be solid lumps of cast iron, or they may
be hollow or perforated. A small quantity of air may be allowed to pass
behind or through the blocks to reduce their temperature. The blocks may
also be single pieces of fire clay or fire stone, or they may consist of several
pieces of the same, or several fire bricks fixed in an iron frame. Thus,
Figure 15 is a side view of a block formed of several fire bricks a, a, united
by an iron frame which is cast upon them. The frame b may be cast with
a back c, as shown in the transverse section, Figure 16; or it may be open,
so as to expose the fire bricks at back and front, as shewn in the section,
Figure 17.
Figure 18 is a transverse section of a steam boiler with the moveable
blocks or cheeks applied to its furnace. A is the boiler; B is the furnace;
C is the ash-pit; Q is the brickwork or masonry; P, P, are the iron frames
built into the brickwork or masonry Q; R, R, are the moveable blocks, as
before. These blocks or cheeks may be applied in a similar manner to other
descriptions of furnaces.
Having now described the nature of my said Invention, and in what
manner the same is to be performed, I wish it to be understood that what

page_text: First, the constructing steam boilers with tubular flues, having a series of
chambers of spherical or other suitable form on their upper surfaces, as herein-
before described.
Second, the constructing fire bars with diagonal channels in their upper
surfaces, in manner herein-before described..
Third, the constructing fire bars with diagonal channels in their upper
surfaces and with their back ends inclined or bent, in manner herein-before
described.
Fourth, the constructing furnaces with fire bars having diagonal channels
in their upper surfaces and with their back ends inclined or bent, as herein-
before described, and so placed that the back ends may incline upwards and
come in contact with or in proximity to the bridge of the furnace, as herein-
before described. ⚫
Fifth, the constructing furnaces with moveable blocks or cheeks fitted into
frames fixed or built into the brickwork or masonry of the furnace, and which
blocks or cheeks are capable of being readily drawn out and replaced by others,
as herein-before described.
In witness whereof, I, the said John Gray, have hereunto set my hand
and seal, this Twenty-ninth day of September, in the year of our Lord
One thousand eight hundred and fifty-six.
Witness,
CHARLES COWPER,
20, Southampton Buildings,
Chancery Lane, London.
JOHN GRAY. (L.S.)