IMPROVEMENTS IN THE CONSTRUCTION OF BOILERS, FOR HEATING AND CIRCULATING WATER
Year: 1873

page_text: LETTERS PATENT to John Metcalf, of Preston, in the County of
Lancaster, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION
OF BOILERS, FOR HEATING AND CIRCULATING WATER."
Sealed the 11th July 1873, and dated the 21st May 1873.

page_text: posed of tubes and terminal ends somewhat in the shape of what is
called a
"saddle boiler," the said tubes being of a triangular form in
section, and so placed together that two of their sides are exposed to
the flame and heat, and thus an extended heating surface is obtained.
The front end of the boiler into which the front ends of the triangular,
tubes are fixed is a hollow box, somewhat in the form of the letter D,
with the flat side downwards thus O, being open through the centre,
and the back or terminal end to which the other ends of the tubes are
fixed is also hollow and of a similar form, but not open in the centre.
The tubes on the flat side or bottom which forms the grate are laid
with the acute angle uppermost, and between them are laid ordinary
furnace bars. The other tubes are fixed with the acute angle inwards
towards the fire and with their sides nearly touching, so as to form two
sides and an arched top, and the heat and flame pass through the centre
to the back where they strike against the terminal end and then return
outside the tubes and between them and an outer wall of tubes to the
front, where they ascend, and then over the arch formed by the inner
tubes and between it and an outer arch formed by another set of tubes,
and thence on to the chimney. The inner and outer sets of side tubes
and the latter and the set of tubes which forms the outer arch are con-
nected together by means of curved syphon pipes, the flow pipe being
connected to the upper set and the return pipe to the lower set. The
flow pipe may be connected to one of the terminal ends, and the whole
is encased in brickwork.
In some cases for small boilers I dispense with the outer set of tubes,
and form the return flues by means of brickwork, the side tubes being
made somewhat shorter than those which form the arch, to allow the
flame and heat to pass round the ends and return outside to the front,
then upwards, and over the top of the arch to the back.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 30
filed by the said John Metcalf, in the Great Seal Patent Office on
the 21st November 1873.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of May, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Metcalf, Her special license that I, the
said John Metcalf, my executors, administrators, and assigns, or such
others as I, the said John Metcalf, 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 Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF
BOILERS FOR HEATING AND CIRCULATING WATER," upon the condition
(amongst others) that I, the said John Metcalf, 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 Metcalf, 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 and accompanying Drawings (that is to say) :-
The object of the said Invention is to obtain a larger amount of
heating surface in a given size of boiler than can be obtained in boilers
of the ordinary construction, and consists principally in forming a
boiler composed of tubes and terminal ends somewhat in the shape of
what is called a "saddle boiler," the said tubes being of a triangular.
form in section, and so placed together that two of their sides are exposed
to the flame and heat, and thus an extended heating surface is obtained..
Such being the nature and object of my said Invention, I will now
proceed to describe more in detail the manner in which the same is
to be or may be performed or carried into practical effect, and in order
that the same may be clearly understood, I have annexed hereunto a
Sheet of Drawings illustrative thereof, and have marked the same with

page_text: figures and letters of reference corresponding with those in the following
explanation thereof:-
Fig. 1 in the annexed Drawing represents a plan view of my improved
boiler complete, Fig. 2 a side elevation, Fig. 3 a longitudinal section,
and Fig. 4, a front elevation of the same.
The front end of the boiler into which the front ends of the triangular
tubes a, a, are fixed is a hollow box b, b, somewhat in the form of the
letter D, with the flat side downwards (see Fig. 4), open through the
centro, and the back or terminal end c, c, to which the other ends of the
tubes a, a, are fixed is also hollow and of a similar form but not open in
the centre. The tubes a¹, a¹, on the flat side or bottom which forms the
grate are laid with the acute angle uppermost, and between them are
laid ordinary furnace bars d, d. The other tubes a, a, are fixed with the
acute angle inwards towards the fire and with their sides nearly touching
so as to form two sides of an arched top, and the heat and flame pass
through the centre to the back, where they strike against the terminal
end c, c, and then return outside the tubes and between them and an
outer wall of tubes e, e, to the front where they ascend, and then over
the arch formed by these outer tubes e, e, and between it and an outer
arch of brickwork f,f, see Fig. 4, and thence on to the chimney. The
inner and outer scts of side tubes and the latter and the set of tubes
which forms the outer arch are connected together by means of curved
syphon pipes g, g, the flow pipe h, h, being connected to the upper set
and the return pipe i, i, to the lower set, or the flow pipe may be
connected to one of the terminal ends b', 6', and the whole is incased in
the brickwork ƒ, ƒ.
In some cases for small boilers I dispense with the outer set of
tubes e, e, and form the return flues by means of brickwork, the side
tubes being made somewhat shorter than those which form the arch, to
allow the flame and heat to pass round the ends and return outside to
the front, then upwards, and over the top of the arch to the back.
Having now described the nature and object of the said Invention,
together with the manner in which the same is to be or may be per-
formed or carried into practical effect, I wish it to be understood that I
claim as my Invention, the peculiar construction of boiler for heating
and circulating water as herein-before described and illustrated by the

page_text: Drawings annexed, or any mere modification or imitation thereof, con-
structed and operating in substantially the same or a similar manner,
and more especially I claim the combination of the triangular formed
tubes with the open and closed D shaped ends arranged in the manner
described.
In witness whereof, I, the said John Metcalf, have hereunto set
my hand and scal, this Fourteenth day of November, in the
year of our Lord One thousand eight hundred and seventy-
three.
Witnessed by
GEORGE DAVIES, C.E.,
Patent Agent,
Manchester.
JOHN METCALF. (L.S.)