IM- PROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS
Year: 1868

page_text: LETTERS PATENT to John Arnold, of Sheffield, in the County of
York, Engineer and Boiler Maker, for the Invention of "IM-
PROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS."
Sealed the 6th April 1869, and dated the 8th October 1868.
PROVISIONAL SPECIFICATION left by the said John Arnold at the
Office of the Commissioners of Patents, with his Petition, on the
8th October 1868.
I, JOHN ARNOLD, of Sheffield, in the County of York, Engineer
and Boiler Maker, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS," to be as
follows:-
This Invention relates, firstly, to what are known as "upright" or
vertical steam boilers, and more especially to such as are provided with
a cross tube (or two or more cross tubes) running through the fire-box
and forming a connection between the water space on opposite sides of

page_text: the fire-box; and, secondly, to what are known as Cornish or horizontal
flue boilers.
The Invention consists principally in inserting a hemispherical, dish-
shaped, conical, or other similarly shaped shallow auxiliary water
space in the fire-box between the top of the latter and the upper side
of the cross tube (or of the upper cross tube if more than one is used),
and in connecting this auxiliary water space at the lower side to the
cross tube by a short tube or ring and at the upper side with the
water space above the top of the fire-box by means of two, four, or
other convenient number of tubes rivetted, screwed, or otherwise fixed
to the upper side of the auxiliary water space and to the top of the
fire-box, so that there may be a free circulation of water between
the water space above the fire-box, the auxiliary water space, and the
cross tube. I may here remark that in cases where the top of the
fire-box is flat I prefer to make the top of the auxiliary water space
flat also, but where the top of the fire-box is curved or dome-shaped
I prefer to make the top of the auxilary space of a similar form, leaving
a space between the two for the passage of the flames and heated gases
to the chimney or smoke flue, which is fixed to and communicates
with the centre of the top of the fire-box, as usual in this class of
steam boilers. Boilers of this class constructed according to my Invention
are particularly suitable for portable, traction, and stationary engines,
and for placing over puddling furnaces used in the manufacture of
wrought iron and steel, and generally whereever steam or steam power
is required, and will be found very economical in use, as the steam
is very quickly raised and the application of the auxiliary water space
in the form and position described assists greatly in the combustion
of the smoke and inflammable gases, and hence effects a great economy
in the consumption of fuel.
In applying my Invention to Cornish or horizontal flue boilers I
employ several auxiliary water spaces (of a form herein-after described)
passing through the flue or flues in a vertical or slightly inclined
position and connecting the water space above the flue with the water
space below the same. The form of the auxiliary water space in this
class of boiler is that of a conical tube with the smaller diameter
downwards and having a hemispherical or dome-shaped top, the top and
the bottom both terminating with a small cylindrical neck with a screw
thread outside, by means of which it is fixed in the top and bottom

page_text: of the flue by means of lock nuts, or they may be rivetted or fixed in
any other convenient manner. By making these auxiliary water
spaces of this form and connecting them with the flue by narrow necks
I obtain a large heating surface in the auxiliaries without much
diminution of the upper heating surface of the flue. I may here observe
that other forms of auxiliaries enlarged at the central part and contracted
at the top and bottom might be employed without departing from the
distinguishing feature of my Invention, but for many reasons I consider
the inverted conical tube with the dome-shaped top preferable.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Arnold in the Great Seal Patent Office
on the 8th April 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ARNOLD, of Sheffield, in the County of York, Engineer and Boiler
Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of October, in the
year of our Lord One thousand eight hundred and sixty-eight, in
the thirty-second year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said John Arnold, Her
special licence that I, the said John Arnold, my executors, adminis-
trators, and assigns, or such others as I, the said John Arnold,
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 STEAM BOILERS," upon the condition
(amongst others) that I, the said John Arnold, my executors or adminis-
trators, 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

page_text: Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said John Arnold, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement in writing, and on reference being had
to the accompanying Sheet of Drawings, that is to say:-
This Invention relates, firstly, to what are known as "upright" or
vertical steam boilers, and more especially to such as are provided with a
cross tube (or two or more cross tubes) running through the fire-box and
forming a connection between the water space on opposite sides of the
fire-box; and, secondly, to what are known as "Cornish " or horizontal
flue boilers.
The Invention consists principally in inverting a hemispherical, dish-
shaped, conical or other similarly shaped shallow auxiliary water space in
the fire-box between the top of the latter and the upper side of the cross
tube (or of the upper cross tubes if more than one is used), and in con-
necting this auxiliary water space at the lower side to the cross tube by
a short tube or ring and at the upper side with the water space above
the top of the fire-box by means of two, four, or other convenient number
of tubes rivetted, screwed, or otherwise fixed to the upper side of the
auxiliary water space and to the top of the fire-box, so that there may be
a free circulation of water between the water space above the fire-box,
the auxiliary water space, and the cross tube. I may here remark that
in cases where the top of the fire-box is flat I prefer to make the top of
the auxiliary water space flat also, but where the top of the fire-box is
curved or dome-shaped I prefer to make the top of the auxiliary space
of a similar form, leaving a space between the two for the passage of the
flames and heated gases to the chimney or smoke flue which is fixed to
and communicates with the centre of the top of the fire-box as usual in
this class of steam boilers. Boilers of this class constructed according
to my Invention are particularly suitable for portable, traction, and
stationary engines and for placing over puddling furnaces used in the
manufacture of wrought iron and steel, and generally wherever steam or
steam power is required, and will be found very economical in use, as
the steam is very quickly raised by the application of the auxiliary water

page_text: space in the form and position described, and which assists greatly in
the combustion of the smoke and inflammable gases, and hence effects
a great economy in the consumption of fuel.
In applying my Invention to Cornish or horizontal flue boilers I
employ several auxiliary water spaces (of a form herein-after described)
passing through the flue or flues in a vertical or slightly inclined position
and connecting the water space above the flue with the water space
below the same. The form of the auxiliary water space in this class
of boilers is that of a conical tube with the smaller diameter downwards
and having a hemispherical or dome-shaped top, the stop and the bottom
both terminating in a small cylindrical neck with a screw thread outside,
by means of which it is fixed in the top and bottom of the flue by means
of lock nuts, or they may be rivetted or fixed in any other convenient
manner. By making these auxiliary water spaces of this form, and
connecting them with the flue by narrow necks, I obtain a large heating
surface in the auxiliaries without much diminution of the upper heating
surface of the flue. I may here observe that other forms of auxiliaries
enlarged at the central part and contracted at the top and bottom might
be employed without departing from the distinguishing feature of my
Invention, but for many reasons I consider the inverted conical tube
with the dome-shaped top preferable.
Such being the nature and object of my said Invention for "Im-
provements in the Construction of Steam Boilers," 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 distinctly understood I have connexed hereunto a
Sheet of Drawings illustrative thereof, and have marked the same with
figures and letters of reference corresponding with those in the following
explanation thereof, that is to say :-
Figure 1 in the annexed Drawings represents a vertical section of an
upright boiler constructed according to my Invention with a fire-box
having a curved or dome-shaped top; Figure 2 is a similar view of a
vertical or upright boiler having a flat top to the fire-box; and Figure 2*
is a horizontal section of the same.
a, a, is the body of the boiler, and 6, 6, the cross tube running through
the fire-box c, c; d, d, is the auxiliary water space, shown in Figure 1

page_text: as dish-shaped and connected to the cross tube b, b, by a short tube e, e,
whilst in Figure 2 it is represented as of an inverted cone or funnel
shape and rivetted to the cross tube, a copper ring or washer f, f, being
interposed to make a more perfect joint. In both these Figures the top
of the auxiliary water space is made parallel with or to follow the form
of the top of the fire-box, (that is to say) in Figure 1 it is curved or
dome-shaped and in Figure 2 it is shown as flat. In both cases it is
shown as connected with the top of the fire-box by short tubes g, g,
which may be fixed in either of the ways shown in the enlarged detached
view, Figure 3, either rivetted as shown at h, h, or screwed and fastened
with a lock nut and copper ring or washer, as shown at i, i, the upper
hole being enlarged and made conical to allow of the introduction of the
screwed end of the tube; the joints must be all caulked in the usual
manner; k, k, is the furnace and I, 1, the chimney.
Figure 4 is a longitudinal section, and Figure 5 a transverse section of
a Cornish boiler constructed according to the second part of my Invention.
a, a, is the shell of the boiler, and b, b, the smoke flues or tubes; c, c,
are the auxiliary water spaces placed either vertically or slightly inclined,
as shown at Figure 5. These auxiliaries are made of a conical form with
a dome-shaped top, and are wrought in one piece, having a cylindrical
neck d, d, at each end formed with a screwed thread on the exterior
surface in order to fix the same in the flues at top and bottom by means
of the lock nuts e, e. The method of inserting and fixing these
auxiliaries is shown clearly in the detached enlarged view, Figure 6. The
upper end of the tube is merely fixed by an ordinary lock nut e, e, and
copper washer.
At the lower end the cylindrical neck d is made
longer and the hole in the flue is made larger for the convenience of
inserting the tube, which is held in its place at the bottom of the plate
by means of the lock nuts and washers. These washers have rims or
collars x, x, formed on them, which when the nuts are screwed home are;
forced to meet in the centre and so fill up the hole formed for the
reception of the tubes, the washers at the top and bottom of the
plate b, b, being properly caulked to render the joints steam and water
tight.
"
Having now described the nature and object of my said Invention for
Improvements in the Construction of Steam Boilers," together with the
manner in which the same is to be or may ha nonformed

page_text: practical effect, I would remark in conclusion that I claim as my
Invention the construction and employment of the auxiliary water spaces
in the manner and for the purposes herein-before more particularly
described.
In witness whereof, I, the said John Arnold, have hereunto set
my hand and seal, this Sixth day of April, in the year of our
Lord One thousand eight hundred and sixty-nine.
JOHN ARNOLD. (L.S.)"