CERTAIN IMPROVELIENTS IN A METHOD OF GENERATING STEAM
Year: 1831

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
DUNN, of Southampton, Engineer, send greeting.
WHEREAS His present most Excellent Majesty King William the
Fourth, by His Royal Letters Patent under the Great Seal of Great Britain,
bearing date at Westminster, the Twenty-first day of February, in the first
year of His reign, did, for Himself, His heirs and successors, give and grant
unto me, the said Samuel Dunn, His especial licence, solo privilege and
authority, that I, the said Samuel Dunn, my executors, administrators, and
assigns, or such others as I, the said Samuel Dunn, my executors, administra-
tors, or assigns, should at any time agree with, and no others, from time to
time and at all times during the term of years therein mentioned, should and
lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, my Invention of "CERTAIN IMPROVELIENTS
IN A METHOD OF GENERATING STEAM;" in which said Letters Patent is contained
a proviso that I, the said Samuel Dunn, shall cause a particular description
of the nature of my said Invention, and in what manner the same is to be
performed, to be inrolled in His said Majesty's High Court of Chancery
within six calendar months next and immediately after the date of the said
in part recited Letters Patent, as in and by the same, reference being there-
unto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Samuel Dunn, do hereby declare that the nature of my said Invention, and in
what manner the same is to be performed, is particularly described and ascer-
tained in and by the following description thereof, reference being had to the

page_text: Drawing hereunto annexed, and to the figures and letters marked thereon,
that is to say:-
My improvements consist in a peculiar mode of applying the flame of ignited
gas to heat a boiler, for the purposes of generating steam, which is effected by
inserting a series of vertical tubes in the boiler, extending upwards from the
bottom, these tubes being heated by gas burners in the manner shewn in the
accompanying Drawing.
Figure 1 is a horizontal section of a circular boiler, containing a series
of vertical tubes. Figure 2 is a vertical section of the same, taken through
the center, the similar letters pointing out similar parts in both figures.
a, a, a, a, is the circular plate, of iron or copper, of which the external part of
the boiler is formed; b, b, is the bottom plate of the boiler, perforated with any
desired number of circular holes, as shewn in Figure 1, into which are inserted
the vertical circular tubes c, c, open at the bottom, and made fast to the
plate b, b, at their open ends, by flanches and screws or rivets, or other suitable
means, which tubes c, c, constitute part of the boiler, and tend to increase the
surface against which the heat is to act. The boiler is surrounded by or with
a jacket or case of iron d, d, corresponding to its own external shape, which
forms a channel surrounding the boiler, for the passage of heated air or vapour
to the chimney c. This boiler and its jacket rests upon the bottom plate f, f
which is made strong by bracing ribs, and is supported upon brickwork or
masonry. The outer part of the jacket is surrounded with sand or charcoal, or
other imperfect conductor of heat, confined by a casing of wood or bricks.
The plate fis perforated with holes corresponding to those in the bottom of the
boiler, but not quite so large, in which holes are inserted pipes g, g, open at
both ends, but having flanches at bottom for fastening them to the plate f.
Each of these pipes, therefore, when so fixed, stands vertically in the centers
of the tubes c, c. They are intended as flues for conducting the flame and
heated air from the gas burners to the surface of the boiler. h, h, h, are
argand burners supplied by service pipes i, i, with gas from a pipe. The
burners are each of them enclosed by chimneys of glass or other material of
the ordinary construction, the upper part of each chimney fitting closely into the
pipes g, in order to prevent as much as possible the passage of atmospheric
air, which should be only passed through the chimney of the burners, to sup-
port the combustion of the gas. The apparatus being so constructed, the flame
and heated air proceeds from the ignited gas at the burners h, h, h, passing up
the pipes marked g, and striking the concave tops of the tubes c, and thence
will descend by the channel between the outer surface of the pipes y and the
inner surface of the tubes c, and after passing under the bottom of the boiler

page_text: will proceed up the external sides, and will escape by the chimney e at top.
The heated air and gas, instead of being returned between the outer sides of
the tubes G, and the inner surface of the tube C, may, by the tubes G being
made to extend to the top of the boiler a, at once pass into the jacket d at the
top of the boiler, and descend through the jacket at the sides of the said boiler
to the bottom thereof, and be there discharged, or instead of being there dis-
charged may be conveyed by a pipe or pipes through the water in the interior
of the boiler, to and through the chimney E, in which case the pipes c may be
dispensed with. By means of either of the arrangements before specified, the
heat from the combustion of the gas will act upon a greatly extended sur-
face of the boiler, and consequently generate steam with great rapidity.
I have by the Drawings hereto annexed, and the foregoing description,
shewn my improved mode of generating steam by means of gas burners applied
within tubes in the interior of a boiler or vessel containing water.
I do not,
however, intend to confine myself to any precise number of burners and tubes,
or to their forms or dimensions, or distance apart, or to the means of passing
off the heated air or gas, or to the particular description of gas to be applied,
but rest my claim of Invention to the application of gas burners to tubes inserted
in or passing through a vessel containing water, for the purpose of producing
or generating steam, for any purpose to which steam may be applicable.
In witness whereof, I, the said Samuel Dunn, have hereunto set my
hand and seal, this Sixteenth day of August, in the year of our Lord
One thousand eight hundred and thirty-one