IMPROVEMENTS IN STRAM BOILERS
Year: 1861

page_text: LETTERS PATENT to James Bremner, of Leith, in the County of Edin-
burgb, North Britain, Engineer, for the Invention of "IMPROVEMENTS
IN STRAM BOILERS"
Sealed the 26th September 1861, and dated the 28th March 1861.
PROVISIONAL SPECIFICATION left by the said James Bremner at the
Office of the Commissioners of Patents, with bis Petition, on the 28th
March 1861.
I, JAMES BREMNER, of Leith, in the County of Edinburgh, North Britain,
Engineer, do hereby declare the nature of the said Invention of "IMPROVE-
MENTS IN STEAM BOILERS," to be as follows, that is to say:-
This Invention has principally for object the combining of extensive and
efficient heating surface, permitting considerable reduction in size and
weight, with facilities for cleaning, economy in fuel, and other advantages;
and also comprises sundry minor improvements.
One modification of boiler, embodying a portion of the improvements, is
square or nearly so in plan at the lower part where the furnace is situated.
The furnace is surrounded by a water space, and is supplied by two doors
arranged so that the two sides of the furnace may be fired alternately in order
[Price 8d.]

page_text: to prevent smoke; the mixing of the fire gases from the two sides being
insured by their having to pass upwards by a narrow throat or opening above
the middle of the furnace. This contraction of the space is caused by inward
extensions from the side of the surrounding water space, and these inwardly
projecting water spaces have tube plates on their upper sides from which tubes
spring in directions slightly inclined inwards from the vertical. The upper
ends of the tubes communicate with a central dome which joins the front and
back portions of the external water space. The fire gases rising up the
throat or narrow middle flue space immediately over the fire, spread right
and left amongst and through between the tubes, and proceed through flue
spaces enveloping the upper dome to the funnel. These flue spaces being
enclosed by fire bricks carried by a metal shell. At a small distance above the
middle of the fire there runs from back to front a pipe through which the feed
water is introduced, and the upper side of this pipe is, by preference, flat, and
it is covered by a semi-cylindrical grating or duct with perforated sides, into
which air is admitted at one or both ends; such air issuing from the per-
forations amongst the gases just at their passage into the throat, and insuring
their ignition. Doors are provided at the sides for access to the lower ends
of the tubes, and there is also a door provided in the dome. An improved
mode of rendering these doors tight is adopted, the aperture being formed with
a rim projecting inwards, which fits in a groove formed in the door, a little
gasket, or similar material, being inserted in the groove. The combined feed
pipe and air inlet is, by preference, fixed in its place in a similar way to
facilitate its removal for cleaning. Sludge doors are provided at the lower
corners of the external water space, and permit the sides to be cleared with
the greatest facility.
In another modification of the boiler the tubes pass up vertically to two
separate domes, and a number of horizontal tubes are disposed about mid-
way up across the space between them. A fire-clay block is placed above
these horizontal tubes to prevent the direct passage upwards of the fire
gases, and obstructing pieces are placed between the vertical tubes to cause
the fire gases to spread outwards amongst the tubes. Above the obstruc-
tions the fire gases return towards the middle of the boiler, and pass upwards
between the upper domes to the funnel.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Bremner in the Great Seal Patent Office on the
28th September 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
BREMNER, of Leith, in the County of Edinburgh, North Britain, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of March, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said James Bremner, Her special licence that I, the said James Bremner, my
executors, administrators, and assigns, or such others as I, the said James
Bremner, 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,"
upon the condition (amongst others) that I, the said James Bremner, 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 James Bremner, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, 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 :-
My said Invention has principally for object the combining of extensive
and efficient heating surface permitting considerable reduction in size and
weight with facilities for cleaning, economy in fuel, and other advantages,
and also comprises sundry minor improvements. One modification of boiler
embodying a portion of the improvements is square or nearly so in plan at
the lower part where the furnace is situated. The furnace is surrounded
by a water space, and is supplied by two doors arranged so that the two
sides of the furnace may be fired alternately; in order to prevent smoke the

page_text: mixing of the fire gases from the two sides being insured by their having to
pass upwards by a narrow throat or opening above the middle of the furnace.
This contraction of the space is caused by inward extensions from the sides of
the surrounding water space,and these inwardly projecting water spaces have
their tube plates on their upper sides, from which the tubes springindirections
slightly inclined inwards from the vertical. The upper ends of the tubes
communicate with a central dome which joins the front and back portions
of the external water space. The fire gases rising up the throat or narrow
middle flue space immediately over the fire spread right and left amongst and
through between the tubes and proceed through flue spaces enveloping
the upper dome to the funnel, these flue spaces being enclosed by fire-bricks
carried by a metal shell. At a small distance above the middle of the fire there
runs from back to front a pipe, through which the feed water is introduced,
and the upper side of this pipe, is by preference flat, and it is covered by a
semi-cylindrical grating or duct, with perforatedsides, into whichairisadmitted
at one or both ends, such air issuing from the perforations amongst the gases
just at their passage into the throat, and insuring their ignition. Doors are
provided at the sides for access to the lower ends of the tubes and there is
also a door provided in the dome. An improved mode of rendering these
doors tight is adopted, the aperture being formed with a rim projecting
inwards, which fits in a groove formed in the door, a little gasket or similar
material being inserted in the groove. The combined feed pipe and air
inlet is by preference fixed in its place in a similar way to facilitate its
removal for cleaning. Sludge doors are provided at the lower corners of
the external water space, and permit the sides to be cleared with the greatest
facility. In another modification of the boiler the tubes pass up vertically
to two separate domes, and a number of horizontal tubes are disposed
about midway up across the space between them. A fire clay block is placed
above these horizontal tubes to prevent the direct passage upwards of the
fire gases, and obstructing pieces are placed between the vertical tubes to
cause the fire gases to spread outwards amongst the tubes. Above the
obstructions the fire gases return towards the middle of the boiler and pass
upwards between the upper domes to the funnel.
And in order that my said Invention of improvements in steam boilers
may be properly understood I shall now proceed to describe the several
Figures on the explanatory Sheets of Drawings which I have hereunto
appended for the purpose of showing certain modifications under which my
improvements may be judiciously carried out in practice, that is to say :-

page_text: Figure 1, on Sheet 1 of the accompanying Drawings, is a front and sectional
elevation of one modification of my improved steam boiler. This boiler being
symetrical on each side of the centre line 1; that part of this Figure to
the right of the line 1 is a front elevation of one half of the boiler, and that
to the left is a sectional elevation taken on the line 2 in Figure 3, Sheet 1.
Figure 2 is a similar half elevation and vertical section taken at right angles
to Figure 1, the half to the right of the centre line 3 being taken on the
line 4 in Figure 3; this Figure is an irregular sectional plan of one half of
the boiler corresponding to Figure 1, the part to the right of the line 1 being
a horizontal section on the line 5, and that to the left a section taken on the
irregular line 6 in Figure 1. The base or lower part of this boiler is of a
square or rectangular form in horizontal section, with rounded corners, and
is arranged with two furnaces A in the width formed of double lengths
of fire bars running from the front plate B to the back C, but having one
common ash-pit a. These fire grates A have each a furnace door b passing
through the water space in the front of the boiler B which admits of charging
or firing the furnaces alternately, for the better burning of the gaseous
products of combustion the smoke evolved from the fresh fuel meets the
flame of the fire, and is ignited at the bridge which divides the two fires.
All round this rectangular basement or combined double furnace there is
formed by the outer sides B, C, and D, and an inner shell or casing E an
outer water and steain space F. This water space begins close to the level
of the furnace bars, and at the front and back extends upwards in a vertical
direction to above the height of the tubes, as shown in Figure 2. At the sides
this space is considerably enlarged over the furnace and bulges outwards in a
curved or crescent form as it extends upwards; the inner and outercasings are
contracted gradually all round from about the water level in the form of a dome
till they are joined at the crown G leaving a circular aperture to receive the
chimney H, A water space I is also formed in the centre of the boiler between
the two furnaces by an inside casing or duct J running between the back and
front inner shells E and joining the water space F of these two sides. The sides
of this water recess J are of a pear shaped figure in transverse vertical section,
and are parallel to each other in horizontal section as shown in Figures 1 and 3
they consequently divide the space over the furnacesinto two large rectangular
segmental flues K. which conduct the flame and gases of combustion up the two
sides of the boiler, and they intermix with each other at the crown G just before
entering the chimney H. Across these two rectangular flues are arranged a
series of tubes c in rows, as shown in Figure 2, but radiating as nearly as

page_text: possible at right angles to the curved surfaces of the two inner shells E and J
of the boiler which form the tube plates for the ends of the whole series of
tubes. The lower rows of tubes are so arranged that the spaces between them
are wider than those above, so as to allow flame easier access to the upper
tubes. The flame from each furnace passes up the flues K, and impinges on
each row in succession until it reaches the top row, where it acts upon the
arched dome E, or if it is not desired, to superheat the steam or act upon the
part of the boiler which contains the steam above the water, the two sur-
faces E and J at this part may be lined with fire-clay bricks supported on
angle iron as indicated by the dotted lines at L. In the centre of the two
sides D,and front B,is formed an improved man-hole door M, having a rim or
raised lip projecting inwards, which enters a corresponding recess formed in
the cover or door; this recess serves to contain gasket or other packing.
The doors are arranged near the ends of the tubes in the two water spaces
Fand I, the space I being made large enough for the withdrawal of old or
the introduction of new tubes. At the rounded corners of the lower part of
the outer water space F are fitted sludge hole doors N, constructed in the
same manner as the man-hole doors M. The two furnaces A are divided
longitudinally by a combined feed valve and air supply bridge Oand P, which
stands considerably higher than the fire, and extends from the front B to the
back C of the boiler. The lower part O, which is rectangular, receives the
water direct from the feed pumps at the one end, and from the other it passes
into the boiler. The under side of this bridge or feed water chamber O is
made in the form of an inverted cover, with flanges and bolts, so as to be
removed at pleasure for the purpose of cleaning out any sludge or sediment
which may collect at this part. The top part P of this duplex bridge is arched
at the top, and partitioned off some little distance from the top by a double-
flanged horizontal plate from that portion O which forms the feed-water
chamber. In a line with the arched part P, at the top of the bridge which
forms a semicircular air tube or duct extending from the front to the back
water spaces F,there are two tubes passing through these water which
spaces
admit a free ingress of atmospheric air at one or both ends to the chamber P.
The passages of these tubes may be controlled by valves so as to regulate the
supply of air to the two furnaces. The air which enters the tubes, after being
heated in the chamber P,passes through elongated narrow slits formed in the
crown of the chamber, as shown and indicated by the arrows in Figures l
and 2. This arrangement of boiler is of the horizontal tubular class,inasmuch
as the tubes c lie in a nearly horizontal position, and gradually diverge towards

page_text: the bottom, so that the currents of flame and heated gases, after impinging
on the lower rows, readily pass upwards to heat the top rows. The currents
of heated water and the steam, as generated, pass upwards through the tubes
in a slanting direction to the central spaces F, thereby keeping up a continual
and regular circulation of the water throughout the boiler. Boilers arranged
on this principle of construction are economical in first cost; they are easily
accessible in all parts, and then generate steam with great rapidity and
economy of fuel.
On Sheet 2 of the accompanying Drawings are shown several views of
another modification of my improvements as arranged and applied to vertical
tubular boilers. Figure 1 is a half vertical elevation and corresponding
section taken through the centre; Figure 2 is a similar elevation and section
taken through the centre,both at right angles to Figure 1; Figure 3 is a half
horizontal section, the part on the left of the centre line being taken a little
above the lower ends of the tubes, and that to the right being taken on a line
through the upper part of the steam space,and looking on the upper ends of
the tubes; Figure 4 is a plan of one-fourth of the boiler, and a fourth hori-
zontal section taken on a line a little above the furnace bars. In this arrange-
ment of the boiler the lower part is constructed very similar to the first modi-
fication. The furnace A is duplex, the ash-pit a having doors in front to
admit air below the fire-bars or not as desired. The two fire grates A are in
this instance formed by three lengths of bars and are separated by a feed-water
chamber perforrated and arranged with tubes passing through the first and
back water spaces F, as in the first modification, and having sludge hole
doors N at the four corners of the lower part of these water spaces. The back
and front water spaces F extend up from the furnace in a vertical direction
till they merge into the large water and steam space I above the upper tube
plates. The inner shells or sides E, of the side water spaces are each
carried inwards in the form of an arch which extends well over the fire
grate immediately it, and is then turned upwards and riveted to a flat tube
plate E. This plate lies at a slight angle, inclined upwards, and extending
outwards to meet the outer shell D, which is carried up until it meets the
outer plate, and is riveted to it, thus enclosing a water space F over each
furnace, which space extends from the front to the back water spaces. The
top or crown of the boiler is arched over at D', and riveted to the outer shell
B' and C. To the lower ends of this arch D', and to a central longitudinal
stay d is firmly riveted the upper tube plates e, lying parallel to the lower tube
plates E. These two pairs of upper and lower tube plates E and E' enclose

page_text: two flue space K, diverging to the right and left into smoke boxes f and from
this upwards into two flues g carried round the arched crown D' of the boiler
to the foot of the chimney H. The smoke boxes are enclosed at the back and
front ends by a plate projecting from the body of the boiler in a line with the
inner lining E,and at the sides by double lined doors for the purpose of getting
at the tubes c to clean them. The tubes care arranged in a nearly vertical
manner at right angles to their tube plates, and in parallel rows, filling the
whole space enclosed by the flue K. The outer covering of the flue g above
the smoke doors h is formed of a double casing of boiler plates enclosing a
superheating space i, supported or attached to the top of the boiler by the
bracketsj. The arched portion B'of the boiler, which forms the steam space I,
is made large enough for the withdrawal or introduction of the tubes c, and is
fitted with a pipe for conveying the steain from this part to the superheating
chamber i, from whence the steam is conveyed by a suitable eduction pipe. A
man-hole door M is formed at the lower part of the chimney, and another M¹,
opening into the water spaces F¹ over the fire places for the purpose of making
the end joints of the tubes. These doors are formed by riveting a ring of
angle iron all round the hole in the shell of the boiler and allowing the edgering
or lip to project inwards and fit into a recess formed in a cast-iron cover l,
which is screwed up tight by two cross bars and four bolts on the outside.
Gasket or other suitable substance for forming the joint is inserted in the
groove of the cover / before screwing it up; the lower portion or side of the
water space F¹ is firmly secured at the arched part over the furnace by
malleable iron stays m to the sides D, and back and front end plates B and C.
The direction of the flame and gases of combustion is indicated by arrows.
These matters pass from the two fire-places, and are carried over the top of
the bridge at P, where the heated air is supplied, which mixes with and ignites
the combustible gases in the central space. The flame and heated. gases
diverge to the right and left through the flues K, and finally pass off by the
sides flues to the foot of the chimney H. The currents of heated water and
the steam as generated in this arrangement of tubular boiler flow in a nearly
vertical direction through the inside of the tubes c, and the water circulates
down the back and front spaces, and thus a regular and uniform circulation is
maintained throughout the boiler. Instead of forming the flue g as shown, the
steam space I may extend to the outer shell of the boiler and the products of
combustion be carried through a series of tubes up to the chimney, the surface
of these tubes serving to superheat the steam.
Having now described and particularly ascertained the nature of my said

page_text: Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that what I consider novel and
original, and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent, is,-
First, the general arrangement, construction, and combination of parts
forming the several modifications of steam boilers as herein-before described
and shown in the accompanying Drawings.
Second, the system or mode of arranging and constructing the internal parts
of boilers according to the several modifications herein-before described and
shown in the accompanying Drawings, or any mere equivalent therefor.
In witness whereof, I, the said James Bremner, have hereunto set my
hands and seal, this Twenty-seventh day of September, One thousand
eight hundred and sixty-one.
JAMES BREMNER. (L.B.)