IMPROVEMENTS IN STEAM BOILERS
Year: 1858

page_text: LETTERS PATENT to John Addy Hopkinson, of Huddersfield, in the
County of York, Engineer, for the Invention of "IMPROVEMENTS IN
STEAM BOILERS."
Sealed the 12th May 1859, and dated the 13th November 1858.
PROVISIONAL SPECIFICATION left by the said John Addy Hopkinson
at the Office of the Commissioners of Patents, with his Petition, on the
13th November 1858.
I, JOHN ADDY HOPKINSON, of Huddersfield, in the County of York,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN STEAM BOILERS," to be as follows:-
My Invention relates, firstly, to an arrangement of tubes or chambers
within the flues of boilers, and consists in connecting one end to the upper
and the other to a lower part of such flues, the intervening portions being
coiled or curved in a spiral, zig-zag, or other form.
Secondly, to a method of attaching the said tubes or other tubes to boilers.
For this purpose I apply a conical hoop of copper or other suitable material
to the tube, which hoop is drawn into an aperture of the boiler plate by a
nut screwed upon the end of the tube.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Addy Hopkinson in the Great Seal Patent Office
on the 12th May 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ADDY HOPKINSON, of Huddersfield, in the County of York, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of November, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Addy Hopkinson, Her special license that I, the said John
Addy Hopkinson, my executors, administrators, and assigns, or such others as
I, the said John Addy Hopkinson, 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 "IM-
PROVEMENTS IN STEAM BOILERS," upon the condition, amongst others, that I,
the said John Addy Hopkinson, by an instrument in writing under my hand
and seal, 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 Addy Hopkinson, 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 and accompanying Drawing (that is to say) :-
My improvements consist in the arrangement of pipes or tubes to steam
boilers, which pipes are of a coiled or spiral form; they are so arranged that
the one end of the pipe is fixed into the upper portion of the flue or chamber,
and the lower end is fixed in at the bottom or side of the flue. The upper
end of the pipe is termed the discharging end, and the lower end the receiving
end; but to make more clear the improvements, I will describe by the Figures
upon the accompanying Drawing.
Figs. 1 and 2 represent sections of a flue boiler; A is the outer shell of a
fire box flue boiler; B is the fire box or flue of the boiler, into which the
pipes are fixed; C is the coiled or spiral pipe, which can either be made
round, eliptical, or of other form; D is the level of the water contained within

page_text: the shell of the boiler A, and surrounding the fire box or flue B. The water
enters into the tube at E, and discharges itself at F. These pipes are made
of iron or other metal, and they are fixed into the fire box or flue or chamber,
as will be hereafter described. They are placed either in the furnace or
behind the bridge, or both, in any number or quantity as circumstances will
admit, and extending towards the back end of the flue or other chamber to
which they are attached. It will be perceived, as the heat of the furnace
comes in contact with the pipes, the temperature of the water at the upper
portion of the pipe increases, consequently it becomes lighter, and begins to
ascend by the weight of the column of water in the boiler which is upon the
lower end of the pipe, and as it ascends and discharges the heated water into
the boiler it is replaced by water of less temperature, until in like manner
the heat is taken up, and the water rises out of the pipe at F, and as it falls
in the boiler it mixes with the water which has been supplied to feed the
boiler, and thus a continual circulation of water is kept up whenever any
heat is given from the furnace. I have been thus particular in mentioning
the circulation of the water, as it is by this mode of circulation that the extra
steam is generated, and it is also of especial benefit to the durability and safety
of a steam boiler, which I have accomplished in the arrangement of these
pipes.
It is well known that the fire box or flue boiler is subject to unequal
expansion and contraction from the difference in the temperature of the water
at the top and at the under side of the flue, which causes the shell of the
boiler to crack and tear asunder. These pipes are devised to prevent to a
very great extent the unequal contraction and expansion, by equalizing the
temperature of the water in the boiler by taking out the colder water from
the bottom, and allowing it to be replaced with the hotter water which has
been heated in passing through the pipes, and given out at F, which again
as it slightly reduces in temperature falls in the boiler and again enters the
pipes, keeping up a constant circulation in the boiler proper, and this I
consider one great improvement. It will also be perceived, from the manner
in which the pipes are fixed behind each other, that the heated gases or
flame pass amongst them, that they present a great amount of absorbing
surface, thereby abstracting the heat in the flue or chamber, and conducting
it into the water, and thus generate steam, and economise the consumption
of fuel.
Having described the pipe or pipes to be of a spiral, coil, or zig-zag form, I
am fully aware of pipes having before been used to steam boilers, where the
feed water previous to entering the boiler proper has been forced through

page_text: them by pumps or other mechanical contrivance, therefore under such cir-
cumstances the circulation of the water through the pipes is dependant upon
the application of mechanical force, whereas under my improvement I
generate steam from the circulation of the water passing through the pipes,
which water has previously been delivered into the boiler proper, and this
is effected independant of any auxiliary or mechanical power, thus making
them self-circulating, and dispensing with valves, pumps, &c. I am also
aware of straight pipes having been placed across and vertically in the flue
of a boiler, and from the contraction and expansion they have soon become
leaky, and with vertical pipes the difficulty has been to preserve them from
burning away by the steam displacing the water from the inner surface of
the pipe, besides the fatal objection of weakening the strength of the flue by
having to pierce it with so many boles so as to get a sufficient number of pipes.
By my arrangement the water in the tubes will not circulate through until
it has attained a higher temperature than the water in the boiler proper:
whenever the flame or gasses from the furnace come in contact with the coils
or curved tubes, steam is generated, and the water in the boiler proper is
caused to circulate, equalizing the temperature, and preventing the unequal
contraction and expansion, as before explained.
;
My improvements are also applicable to locomotive boilers, and in such
cases I place the tubes or pipes in a zig-zag or spiral form in the fire box,
attaching the lower end of the pipe to the lower end of the fire box, thereby
effecting a circulation through the tubes, and consequently circulating the
water surrounding the fire box. I also apply these pipes, as before stated,
in the furnace, that air may pass up the inside of the coil, and through the
interstices of each layer of pipes, so as to assist combustion, and the pre-
vention of smoke. For marine boilers they are applied in the furnace or
chamber, or both, to effect the same purpose as in the stationary or locomotivė
boiler.
My improvement in fixing tubes to steam boilers is shewn at Figs. 3
and 4, and consists in the adaptation of adjustable collars or hoops, which I
propose to be made of copper or other suitable metal. The end of the pipė
or tube D is screwed, and the hoop A is made to screw on the outside, and is
turned a little taper. The hoop is screwed on the outside of the pipe to such
a depth as admits of the pipe end passing through a hole in the boiler plate.
This hole is made of an exact size, to allow the hoop partially to enter the
hole. A nut B is then screwed on the pipe on the other side of plate, and
by screwing down the nut the conical hoop is drawn into the hole, and as the
nut is twitched by key or lever, the hoop is drawn still firmer into the hole,

page_text: and a tight joint is made; or should it be desirable, the nut and hoop may
be placed on the opposite side, that is, the nut may be first screwed on the
pipe end, and the pipe end passed through a hole as before, and tightened by
means of the nut. In places where it is desirable to dispense with the nut,
the hole in the boiler would require to be tapped, and instead of the collar
having a smooth conical surface, it would be screwed inside to fit the pipe,
and screwed on the outside to fit the hole in the boiler; thus it will be seen
that on turning round the hoop it screws into the boiler plate, and forms a
tight joint. The object in fixing the tubes in the manner here described is
to facilitate the fixing or the renewal of the tubes. Should there be a leak
at any time through the pipe and collar, or the collar and boiler plate, the
nut or collar only requires screwing tighter, and the leakage will be stopped;
this cannot be effected by the ordinary method in which tubes are fixed.
Having thus described and ascertained the nature of my said Invention,
and the manner in which the same is to be performed, I desire it to be
understood that I claim under the above in part recited Letters Patent, the
adaptation of curved pipes placed in the furnaces, flues, or chambers of
steam boilers, which effect a continual and uninterrupted circulation of water
in the boiler and through the tubes to the upper side of flue or flues, so long
as heat is applied, that circulation being obtained independant of pumps or
valves or other such means. I claim as my improvements in fastening pipes
or tubes in boilers, an adjustable plain, conical, or threaded hoop, screwed on
the outer end of the pipe, fitting a suitable hole in boiler, and holding the
pipe fast in its place by means of a nut and screw.
In witness whereof, I, the said John Addy Hopkinson, have hereunto
set my hand and seal, this Tenth day of May, in the year of our
Lord One thousand eight hundred and fifty-nine.
JOHN ADDY HOPKINSON. (L.S.)