IMPROVEMENTS IN STEAM BOILERS AND FURNACES
Year: 1858

page_text: LETTERS PATENT to John Braidwood, of Glasgow, in the County of
Lanark, North Britain, Engineer, for the Invention of "IMPROVEMENTS
IN STEAM BOILERS AND FURNACES."
Sealed the 12th October 1858, and dated the 26th April 1858.
PROVISIONAL SPECIFICATION left by the said John Braidwood at the
Office of the Commissioners of Patents, with his Petition, on the
26th April 1858.
I, JOHN BRAIDWOOD, of Glasgow, in the County of Lanark, North Britain,
Engineer, do hereby declare the nature of the said Invention of "IMPROVE-
MENTS IN STEAM BOILERS AND FURNACES," to be as follows, that is to say :-
This Invention relates to certain apparatus to be applied to steam boilers,
having for object the removal of sediment therefrom, and to certain improve-
ments in steam boiler and other furnaces, having for object the thorough
combustion of the fuel and the protection of the fire-bars. The apparatus for
removing the sediment from steam boilers consists, according to one modification,
of a vessel communicating by two pipes or passages with the water in the boiler.
One of these pipes or passages opens inside the boiler at or near the level of the
water, whilst the other opens as near the bottom of the boiler as is convenient.
The sediment vessel may be of various forms, but it is essential that it be of a
larger calibre than that of the pipes communicating with it, and it must
descend below the point at which the lowermost pipe opens into it. When the
boiler is in action the water in the vessel becomes cool, and descending enters
the boiler by the lower pipe, whilst its place is supplied by the upper pipe, and

page_text: a current is thereby produced. In consequence of the size of the vessel, the
water descends through it at a much slower rate than that of its passage
through the pipes, and as it descends in this way the matters suspended in it
are precipitated to the bottom, whence they are removed by a blow-off cock or
otherwise. The rapidity of the current may be increased by cooling the
sediment vessel by a stream of water or otherwise. The form or arrangement
of the apparatus may be modified in various ways, but the essential feature of
this part of the Invention is the production of a current through the boiler and
a separate vessel, and the contriving that this current shall be slower at one
part of its passage through the separate vessel so as to deposit the matters
suspended in it.
The improvements in furnaces consist in arranging the fire-bars so
to be inclined in plan to the horizontal centre line of the furnace. It is
preferred to place them at an angle of 45°, but the angle may be somewhat
greater or less than this if circumstances render it desirable, the intention
of this arrangement being that the air rising up between the bars shall flow
obliquely across them towards the inner end of the furnace with the view of
preventing the accumulation of clinkers on the bars. It is also preferred to
make the inner end of the grate higher than the outer end, so that the green
smoke from the fresh fuel near the mouth of the furnace may be compelled to
flow closely over the incandescent fuel at the inner end.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Braidwood in the Great Seal Patent Office on the
25th October 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
BRAIDWOOD, of Glasgow, in the County of Lanark, North Britain, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of April, in the year of our Lord'
One thousand eight hundred and fifty-eight, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me
the said John Braidwood, Her special licence that I, the said John Braid-
wood, my executors, administrators, and assigns, or such others as I, the
said John Braidwood, 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,

page_text: use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN STEAM BOILERS AND FURNACES," upon the condition (amongst others)
that I, the said John Braidwood, 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 Braidwood, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to say:-
it.
My said Invention relates to certain apparatus to be applied to steam boilers,
having for object the removal of sediment therefrom, and to certain improve
ments in steam boiler and other furnaces, having for object the thorough com-
bustion of the fuel and the protection of the fire bars. The apparatus for
removing the sediment from steam boilers consists, according to one modifi-
cation, of a vessel communicating by two pipes or passages with the water in
the boiler. One of these pipes or passages opens inside the boiler at or near
the surface of the water, whilst the other opens as near the bottom of the
boiler as is convenient. The sediment vessel may be of various forms, but it
is essential that it be of a larger calibre than the pipes communicating with it,
and it must descend below the point at which the lowermost pipe opens into
When the boiler is in action the water in the vessel becomes cool, and
descending enters the boiler by the lower pipe, whilst its place is supplied by
the upper pipe, and a current is thereby produced. In consequence of the
size of the vessel the water descends through it at a much slower rate than
that of its passage through the pipes, and as it descends in this way the
matters suspended in it are precipitated to the bottom, whence they are
removed by a blow-off cock or otherwise as they accumulate. The rapidity
of the current may be increased by cooling the sediment vessel by a stream of
water or otherwise. The form or arrangement of the apparatus may be modified
in various ways, but the essential feature of this part of the Invention is the
production of a current through the boiler and a separate vessel, and the
contriving that this current shall be slower at one part of its passage through
the separate vessel so as to deposit the matters suspended in it.
The improvements in furnaces consist in arranging the fire bars so as to

page_text: be inclined in plan to the horizontal centre line of the furnace. I prefer to
place them at an angle of 45°, but the angle may be somewhat greater or less
than this if circumstances render it desirable, the intention of this arrange-
ment being that the air rising up between the bars shall flow obliquely
across them towards the inner end of the furnace, with the view of preventing
the accumulation of clinkers on the bars. I also prefer to make the inner
end of the grate higher than the outer end, so that the green smoke from the
fresh fuel near the mouth of the furnace may be compelled to flow closely
over the incandescent fuel at the inner end.
And, in order that my said Invention may be properly understood and
carried into effect, I have delineated upon a Sheet of explanatory Drawings
hereunto appended, and shall now proceed to particularly describe, sundry
modifications embodying it. The same reference letters mark the like parts
in all the Figures.
Figure 1 on the Sheet of Drawings is an elevation, partly in section, of a
steam boiler with a modification of my sediment separator fitted to it. The
separator is in this instance a closed cylindrical iron vessel A, which com-
municates with the boiler B by two pipes, one, C, entering the boiler at about
the water surface line, and the other, D, entering at the bottom. This
arrangement has the effect of producing a current in the water in the boiler
and separator, the water passing from the boiler through the upper pipe C
into the top of the separator A, and back into the boiler through the lower
pipe D. In consequence of the calibre of the separator A being greater than
that of the pipe C, the current becomes retarded when passing through the
separator, and the matters held in suspension in the water fall to the bottom
of the separator. The separator A is extended below the re-entrance pipe D
to form a receptacle for the deposited matters, and it is provided with a blow-
off cock E and with a door F, for inspecting the interior and for removing.
the deposited matters. The pipe C projects a short distance into the boiler,
as shown in the sectional detail plan, Figure 2, and is formed with a species
of funnel mouth with the view of, as it were, collecting the surface water.
When the boiler is fed with comparatively cold water, the feed water may be
introduced into the separator to accelerate the current by its cooling action.
The apparatus represented in Figure 1 is arranged for receiving the feed
water by a pipe G, which first enters a space between the sides of the
separator and a shell H. This shell H descends a little below the re-entrance
pipe D, and prevents the feed water mixing directly with the water which has
just entered the separator from the boiler, whilst it, however, surrounds it and
tends to cool it.

page_text: Figure 3 on the Sheet of Drawings is an elevation of a vertical boiler of
the kind frequently heated by the waste heat from reverberatory or puddling
furnaces, with my sediment separator fitted to it. In this instance arrange-
ments are not made for introducing the feed water into the separator, but in
other respects it resembles that represented in Figure 1, and already described.
The boiler B is shown broken away at the side to exhibit the mouthpiece of
the pipe C, which is made with an inclined oblong opening, admitting of a
slight variation of the water level without affecting the working of the
apparatus.
Figure 4 is a side elevation, and Figure 5 is an end elevation, of an
arrangement which I recommend in the case of very long boilers. In this
case the separator A is placed horizontally, and it has two pipes C, one at
each end, communicating with the boiler B near the water surface line. A
single pipe D from near the middle of the separator A forms the return com-
munication with the bottom of the boiler. With this arrangement there will
be two currents, one directed to each pipe C, and the two meeting in the
separator A, and re-entering the boiler together by the pipe D.
Figure 6 is a sectional elevation, shewing a mode of arranging the sepa-
rator inside a boiler. In this case the separator A is of a conical form, and
the current enters at an oblique opening I formed at the top. A pipe J
passes laterally from the separator A through the side of the boiler B, and
through the boiler seating. It is carried down obliquely outside the boiler
seating, as indicated by dotted lines, and finally returns and enters the boiler
at a point K as near the bottom and as far from the separator A as con-
venient. In this case the current through the separator is produced by the
cooling of the water in the external pipe between J and K.
The proportions and sizes of the various parts of my sediment separator
depend on circumstances and conditions which will vary in each case, but
I may observe that the proportions indicated by the Drawings are such as I
have found to answer extremely well in practice. (The boiler represented in
Figure 1 may be supposed to be 26 feet long, that represented in Figure 4,
36 feet long, and that represented in Figure 6, 20 feet long.) I may also here
observe that my sediment separator may be advantageously used wherever the
water supplied to the boiler is of such a nature as to hold injurious matters
of any kind in suspension at or near its surface when the boiler is in action,
and to deposit or precipitate them on becoming comparatively quiescent.
Figure 7. on the Sheet of Drawings is a longitudinal vertical section, and
Figure 8 is a plan (the former being taken as along the line a, b, in the
latter), explanatory my improvements in furnaces, and representing the

page_text: grate of a steam-boiler furnace. The grate bars are inclined in plan to
the horizontal centre line, or to the sides of the furnace. In this case the
bars on each side of the centre line are inclined in opposite directions, but in
narrow furnaces they may be all inclined one way. I prefer to cast the bars
in sets of five or other convenient number, each, that is to say, so that the
five of each set shall be in one piece, being united at the ends, in which case
one bar of each set should be made deeper than the rest, as shewn in
Figure 7. I also prefer to give the grate surface an upward inclination
towards the inner end of about the degree shewn in Figure 7, for the reasons
herein-before explained.
Having thus particularly described my said Invention, and the manner in
which the same is or may be used or carried into effect, I have to state that
I do not restrict myself to the precise details herein-before delineated and
described, and that I do not claim to have invented every separate detail
herein-before delineated or described; but that what I consider to be novel
and original, and claim as the Invention secured to me by the herein-before
in part recited Letters Patent, is,―
First, the collection and removal of matters held in suspension in the water
employed in steam boilers by means of apparatus such as is herein-before
described.
Second, the system or mode of arranging the grate bars of steam boiler and
other furnaces so as to be inclined in plan to the longitudinal centre lines of
the furnaces, as herein-before described.
In witness whereof, I, the said John Braidwood, have hereunto set my
hand and seal, this Twenty-third day of October, in the year of our
Lord One thousand eight hundred and fifty-eight.
Witness,
EDMUND HUNT, Patent Agent,
28, St. Enoch Square, Glasgow.
JOHN BRAIDWOOD. (L.S.)