IMPROVEMENTS IN STEAM BOILERS
Year: 1859

page_text: LETTERS PATENT to Alexander Chaplin, of Glasgow, in the County of
Lanark, North Britain, Engineer, for the Invention of "IMPROVEMENTS
IN STEAM BOILERS."
Sealed the 7th October 1859, and dated the 7th April 1859.
PROVISIONAL SPECIFICATION left by the said Alexander Chaplin at
the Office of the Commissioners of Patents, with his Petition, on the
7th April 1859.
I, ALEXANDER CHAPLIN, of Glasgow, in the County of Lanark, North
Britain, Engineer, do hereby declare the nature of the said Invention of
"IMPROVEMENTS IN STEAM BOILERS," to be as follows, that is to say:-
This Invention relates more particularly to steam boilers of the "vertical"
or "upright" tubular class, and comprehends several in the construction of
such boilers.
A first improvement consists in forming the tubes for the passage upwards
of the fire gases, with a contraction slightly below the water surface line, the
tubes being re-expanded again in sectional area from the contracted part to
the water surface line, and above it if desired. The tubes are continued
through the steam space or through a part of it, so as to dry the steam, whilst
from their improved form they will be uninjured by the fire gases, since these
expanding above the contraction will be thereby reduced in temperature. The
tubes may be variously shaped. Thus the tubes may have parallel sides above
and below the contraction, or they may have parallel sides on one side of the

page_text: contraction, and be conical on the other side of it, with the narrowest part of
the cone at the contraction, or they may be conical both above and below the
contraction. The tubes may be formed in various ways, as, for example, by
swaging in paralled sided tubes, or by inserting short pieces of tubing inside
the tubes, or by joining two pieces of tubing, of the full size, upon a short
piece of smaller calibre, or again by swaging in the ends of two pieces of
tubing, and then uniting them. This improvement is applicable to all boilers
in which tubes conveying the fire gases cross the water-surface line in either
vertical or inclined directions.
A second improvement consists in so proportioning the tubes of a circular
upright boiler that the fire gases may be more equally distributed amongst
the tubes, this being effected by making the tubes more contracted towards
the centre.
A third improvement is designed to check the priming so common in
upright tubular boilers, and consists in contracting such boilers with an
upwardly increasing horizontal area at the water-surface line, so that as the
water rises from priming a gradually increasing surface is presented to the
opposing pressure of the steam above it. The enlargement of the boiler may
commence at the water surface line, or a little below it, or the boiler may be
formed with a gradually enlarging taper from the bottom to the top.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Chaplin in the Great Seal Patent Office on the
7th October 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
CHAPLIN, 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 Seventh day of April, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-second year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Alexander Chaplin, Her special licence that I, the said
Alexander Chaplin, my executors, administrators, and assigns, or such others
as I, the said Alexander Chaplin, my executors, administrators, or 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

page_text: 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 Alexander Chaplin, my executors or administrators, by an instru-
ment 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Alexander Chaplin, do hereby declaro
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 in writing, reference being had to the accompanying Drawings and
to the letters and figures marked thereon, that is to say :-
My said Invention relates more particularly to steam boilers of the vertical
or upright tubular class, and comprehends several improvements in the con-
struction of such boilers.
.
And in order that my said Invention may be properly understood and
carried into effect, I shall refer as I proceed with the particular description
thereof, to the accompanying Sheet of explanatory Drawings, upon which I
have delineated sundry examples of the application of my improvements,
premising that the same reference letters mark the same or like parts in all
the Figures.
A first improvement consists, in forming the tubes for the passage upwards.
of the fire gases, with a contraction slightly below the water surface line, the
tubes being re-expanded again in sectional area from the contracted part
to the water surface line, and above it if desired. The tubes may be of
various shapes, sundry examples thereof being shown in Figures 1 to 5 of the
Drawings. Thus the tubes may have parallel sides above and below the con-
traction C as shown in Figure 1, or they may have parallel sides on one side
of the contraction C, and be conical on the other side of it, with the narrowest
part of the cone at the contraction as shown in Figures 2 and 3; or they may
be conical both above and below the contraction C as shown in Figure 4; or
finally, they may be formed with several contractions and enlargements, C, c, c,
beneath the water surface line A, B, as shown in Figure 5; Figures 6 to 10
of the Drawings are vertical sections of various classes of vertical tubular
boilers showing the application of my improved tubes. The tubes D arc in
each case continued through the steam space E, or through a part of it, so
as to dry the steam, whilst from their improved form they will be uninjured
by the fire gases. The object of the contraction C, (or contractions C, c, c,),

page_text: is to concentrate the heat so as to impart a greater proportion to the water
at that part, whilst the gases re-expanding above will be thereby considerably
reduced in temperature. The tubes may be formed in various ways, as, for
example, by swaging in parallel-sided tubes, or by inserting short pieces of
tubing inside the tubes; or by joining two pieces of tubing of the full size upon
a short piece of smaller calibre; or, again, by swaging in the ends of two pieces
of tubing, and then uniting them.
This improvement is applicable to all boilers in which tubes conveying the
'fire gases cross the water surface line A, B, in either vertical or inclined
'directions. Thus, in Figure 10 is represented an example of boiler in which
the lower parts of the tubes D are curved, bent, or inclined, whilst the parts
crossing the water-surface line A, B, and the steam space E are vertical, or
nearly so.
A second improvement consists in so proportioning the tubes of a circular
upright boiler that the fire gases may be more equally distributed amongst the
tubes. With a set of tubes of equal calibre, the currents of the gasos tend to
be stronger through those at and near the centre. By the present Invention,
however, the tubes at and near the centre are made of smaller calibres than
those of the outer ones; or, when my improved form of tube is adopted, the
same end may be obtained by making the tubes at and near the centre more
contracted at the parts C, than the outer tubes.
A third improvement is designed to check the priming so common in.upright
tubular boilers, and consists in constructing such boilers with an upwardly
increasing horizontal area at the water surface line, A,B, Figures 6, 7, and 8;
so that as the water rises from priming, a gradually increasing surface is pre-
sented to the opposing pressure of the steam above it. The enlargement of
the boiler may commence at the water surface line A, B, or a little below it,
as in Figures 7 and 8, or the boiler may be formed with a gradually enlarging
taper from the bottom to the top.
It remains to be stated that whilst in applying my improved tubes D, I
prefer to form the steam space E below the upper tube plate F (Figures 7
and 8). I at the same time take advantage of the gases in the smoke
dome G, or space for collecting the gases from the tubes D, by surround-
ing such dome or space (and also, if desired, the lower part of the funnel II,
as shown in Figure 7) with a casing I in which the feed water may be heated
or in which the steam may be superheated. I may also mention that the
modification of boiler represented in Figure 9 is specially designed to take in
my improved tubes D of an extra length, as compared with the height of the
boiler. To this end the furnace J is placed to one side, and the fire gases
.

page_text: pass from it down into a low-lying combustion chamber K, beneath the
bottom tubo plate. This arrangement has the advantage of being free from
the production of smoke.
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 described or
delineated, and that I do not claim to have invented every separate detail
herein-before described and delineated; 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 constructing of boilers with tubes crossing the water surface line,
such tubes being contracted below such line, and re-expanded substantially as
herein-before described.
Second, the combining in boilers of tubes of different effective calibres, so
as to obtain more equal currents throughout the series, substantially as
herein-before described.
Third, the constructing of vertical tubular boilers with increasing horizontal
area internally, at and immediately above the water surface line, substantially
as herein-before described.
In witness whereof, I, the said Alexander Chaplin, have hereunto set
my hand and scal, this
day of October, in the year of our Lord
One thousand eight hundred and fifty-nine.
Witness,
EDMUND HUNT, Patent Agent,
28, St. Enoch Square, Glasgow.
ALEX. CHAPLIN. (L.S.)