IMPROVEMENTS IN SHEET-FLUE AND TUBULAR BOILERS
Year: 1858

page_text: LETTERS PATENT to John Thomas Robson, of No. 45, Hugh Street,
West, Pimlico, in the County of Middlesex, Engineer, for the Invention
of IMPROVEMENTS IN SHEET-FLUE AND TUBULAR BOILERS."-A com-
munication.
Sealed the 5th November 1858, and dated the 8th May 1858.
PROVISIONAL SPECIFICATION left by the said John Thomas Robson
at the Office of the Commissioners of Patents, with his Petition, on
the 8th May 1858.
I, JOHN THOMAS ROBSON, of No. 45, Hugh Street, West, Pimlico, in the
County of Middlesex, Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN SHEET-FLUE AND TUBULAR BOILERS," (a com-
munication), to be as follows:-
This Invention consists in arranging the flues of marine and other steam
boilers one above the other in a serpentine form, extending from front to back
of the boiler. Between these flues, and at intervals, are oval tubes, placed.
vertically and in such a manner that the second row of tubes are seen between
the spaces of the front row; tubes are also placed horizontally at the bend
of each flue. It will thus appear evident that as the flame strikes against the
first row of horizontal tubes, it spreads, and coming into contact with one.
row of vertical tubes, it is again divided, and passing on each side, strikes the

page_text: next row of tubes, and so on from one flue to another, thereby obtaining a
greater amount of heating surface than heretofore, and at the same time
affording every facility for cleaning or repairing.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Thomas Robson in the Great Seal Patent Office on
the 8th November 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
THOMAS ROBSON, of No. 45, Hugh Street, West, Pimlico, in the County of
Middlesex, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of May, 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 Thomas Robson, Her special licence that I, the said John
Thomas Robson, my executors, administrators, and assigns, or such others
as I, the said John Thomas Robson, 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 Inven-
tion for "IMPROVEMENTS IN SHEET-FLUE AND TUBULAR BOILERS," (a communication,)
upon the condition (amongst others) that I, the said John Thomas Robson,
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 Thomas Robson, 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, that is to say :-
This Invention consists in arranging the flues of marine or other steam
boilers one above the other in a serpentine form, extending from front to back
of the boiler. Between these flues, and at intervals, are oval tubes, placed
vertically and in such a manner that the second row of tubes are seen

page_text: same into practical effect, and refer to the accompanying Sheet of Drawings,
and the figures and letters of reference marked thereon, the same letters being
used to denote corresponding parts at each Figure.
DESCRIPTION OF THE DRAWING.
Figure 1 is a front elevation, having the front plate attached; Figure 2,
longitudinal section; and Figure 3, plan view, taken through the line A, B,
at Figure 2.
a, a, are the stoke-holes; b, b, the flues; c, c, water spaces; d, d, vertical
tubes; and e, e, horizontal tubes. It will be seen at Figures 2 and 3, that
as the flame ascends from the stoke-holes or furnace a, a, the horizontal
tubes e, e, separate it, causing it to strike (in coming forward) against the
back row of vertical tubes d, d, in the direction of the arrows, said tubes being
exactly opposite the spaces between the horizontal tubes e, e, the second row of
vertical tubes being exactly opposite the spaces between the first row, and so
on through the entire boiler, see Fig. 3. Care should be taken that sufficient
space be left between the tubes (which are equidistant) to allow of a man
passing between them for the purpose of cleaning or repairing them, when
required. Thus it will appear evident, that by these means not only is the
heat applied to the upper parts of the various serpentine flues, but the
horizontal and vertical tubes also are exposed to the action of the fire, thereby
exposing a large heating surface, and the flue, being in a serpentine form,
will tend to consume the smoke and gases, the heat, therefore, being more
intense, combustion having taken place.
Having now fully described and set forth the nature and object of the said
Invention of "Improvements in Sheet-Flue and Tubular Boilers," together
with the best means I am acquainted with for carrying the same into practical
effect, I would remark that I do not confine or restrict myself to the number
of serpentine flues, or the precise shape or number of tubes, as more or less
may be used according to the size of the boiler, and the purpose for which it

page_text: is required; but what I claim as my Invention, intended to be secured to me
by the said in part recited Letters Patent is, the forming of marine or
other steam boilers of serpentine flues, having connecting tubes between each,
whereby a larger heating surface is exposed to the action of the fire, and
consequent speed in generating steam.
In witness whereof, I, the said John Thomas Robson, have hereunto
set my hand and seal, this Sixth day of November, in the year of our
Lord One thousand eight hundred and fifty-eight.
Witness,
JOHN THOMAS ROBSON. (L.S.)
ALEX. PRINCE, Patent Agent,
4, Trafalgar Square, Charing Cross.