IMPROVEMENTS IN BOILERS AND FURNACES FOR PRODUCING SUPERHEATED STEAM
Year: 1869

page_text: LETTERS PATENT to Robert Boyd, of the Firm of Herbert and
Company, of 67, Strand, in the City of Westminster, Patent
Agents, for the Invention of "IMPROVEMENTS IN BOILERS AND FURNACES
FOR PRODUCING SUPERHEATED STEAM."-A communication from abroad
by Alexander Gemmell, of Croix, near Roubaix, Engineer, and
Louis Fontaine, of Madelene, near Lille, both in the Empire of
France.
Scaled the 3rd December 1869, and dated the 22nd July 1869.
COMPLETE SPECIFICATION filed by the said Robert Boyd at the-
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 22nd July 1869, pursuant to the 9th Section.
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
BOYD, of the Firm of Herbert and Company, of 67, Strand, in the City
of Westminster, Patent Agents, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN BOILERS AND FURNACES FOR PRODUCING SUPERHEATED STEAM," and have
petitioned Her Majesty to grant unto me, my executors, adminis-
trators, and assigns, Her Royal Letters Patent for the same, and have

page_text: made solemn Declaration that the same is a communication from
abroad by Alexander Gemmell, of Croix, near Roubaix, Engineer, and
Louis Fontaine, of Madelene, near Lille, both in the Empire of
France.
NOW KNOW YE, that I, the said Robert Boyd, do hereby declare that
the following Complete Specification, under my hand and seal, fully
describes and ascertains the nature of the said Invention, and in what
manner the same is to be performed, in and by the following statement,
that is to say:-
The Invention consists in the combination with a triple vessel or
elephant boiler of an additional steam generating vessel beneath the
others, all connected in respect of water space, and the making the
additional vessel with internal tubes therein, and the construction of
the furnace and disposition of its passages or flues so as to cause the
flame and gases firstly to impinge on a portion of the length of the upper
vessels, or of some of them, then through the tubes of the additional
or bottom vessel, and afterwards both through tubes in the top vessel
and against its external surface or against the external surface only, and
not through the tubes in the passage or current of the flame and gases
towards the chimney, the said top vessel being converted into and used as
a superheater for superheating the steam.
In the accompanying Drawing an example of the construction and
arrangement of boiler and furnace above referred to is represented as
illustrative of the manner in which the Invention is to be and may be
performed.
Figures 1, 2, 3, are longitudinal and transverse sections and a plan
view respectively. The Figure 1 is drawn in some respects incorrectly,
that is to say, instead of multiplying the number of Figures one view is
made to serve instead of two or more views, and the plane of the section
is stepped or broken at intervals the more clearly to exhibit parts
which would not appear (or not so clearly so) if the Figures were drawn
in one plane of section.
A is the bottom vessel or additional steam generator; B, B, are
smaller side boilers or generators; and C is the top vessel or super-
heater. The two vessels B, B, and the top one C, without the vessel A,
but suitably mounted, would constitute an elephant boiler of the
ordinary description. These and the generator A are all connected (as
to water space) by the junction passages D, which are constructed of

page_text: copper or other suitable material to allow of expansion and contraction
as required. The generator A does not extend the length of the other
vessels, but the fire-grate E is placed in line therewith and underneath
the overhanging parts of the vessels B, B, and C. The consequence is
that in respect of these overhanging parts the whole of B, B, and the
under part of C are externally exposed to the first action of the flame and
gases, but the arrangement not permitting these to pass direct to the
chimney they are compelled while retaining their original force to go
over the bridge of the furnace and through the tubes a of the generator A
to the back or further end; they next turn upwards, and then pass
along the entire length of the tubes c, c, of the superheater to the front,
and finally again return to the back, and pass towards the chimney by
the upper flues c*, c*, situate at the sides of and against the super-
heater C. The arrows in Figures 1 and 3 denote the current, and are
numbered in serial order to render the explanation the more intelligible.
F is an ordinary balanced furnace door for generally regulating the
draft; and in addition thereto are two small dampers G, G, situate at
the back of gencrator A over openings in the partition wall H, and
a damper I at one end of the tubes through the superheater. By theso
a variation in the direction of the current is producible when desired,
and the quantity of steam and amount of superheating can be regulated
without interfering with the continued action of the furnace, the effect
being either partially or entirely to divert the flame and gases from
acting internally, that is to say, through the tubes of the generator and
of the superheater. K is another damper over a direct exit flue to the
chimney to be used in conjunction with the others as desired. L, L, are
doors for access to the various parts of the furnace, and others may be
added where required. And all necessary man-holes or caps to the
several vessels A, B, B, and C are to be provided, though only partially
represented in the Drawing. It is to be understood that the tubes c of
the superheater may sometimes be omitted, in which case the current
of the flame and gases may pass in one direction along one of the flues c*,
and in the opposite direction along the other. Pyrometers exposed one
or more to the flame and gases, and one or more to the steam, may be
placed within sight of the attendant, who can then judge to what extent
it may be desirable to divert the currents.
It will be evident from inspection of the Drawings, and from the above
description, that the Invention offers the means of evaporating a large
quantity of water in a comparatively small space with prompt circulation

page_text: of the water and direct production of superheated steam in the combined
apparatus, together with the means of controlling the draught and
amount of superheating according to purpose for which it may be
applied, and with great facility for cleansing and repairs.
And I would remark that the position of the superheating vessel C
need not necessarily be as shewn in the Drawing, but may be varied,
and that although I have represented and described only one super-
heating vessel as employed in the combination with other parts, there
may be employed if desired two or more superheating vessels with or
without internal tubes, the mounting of the said superheaters. and the
arrangement of flues around them being varied as the circumstances.
may require.
In witness whereof, I, the said Robert Boyd, have hereunto set
my hand and seal, this Twenty-first day of July, in the year
of cur Lord One thousand eight hundred and sixty-nine..
ROBERT BOYD, (L.S.).