IMPROVEMENTS IN STEAM BOILERS
Year: 1857

page_text: LETTERS PATENT to David Patridge, of Woolwich, in the County of Kent,
Engineer, for the Invention of "IMPROVEMENTS IN STEAM BOILERS."
Sealed the 28th August 1857, and dated the 2nd March, 1857.
PROVISIONAL SPECIFICATION left by the said David Patridge at the
Office of the Commissioners of Patents, with his Petition, on the 2nd
March 1857.
I, DAVID PATRIDGE, of Woolwich, in the County of Kent, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN STEAM
BOLLERS," to be as follows:-
My Invention of improvements in steam boilers relates to that description of
steam boilers, or generators, in which superheated as well as common steam are
produced for the purpose of being used in combination in engines for propel--
ling vessels or machinery. One of the principal objects of my present
improvements is to construct and arrango. the superheating apparatus, in such
a manner that it can be more conveniently employed for the intended purpose
than the ordinary superheating apparatus, and may be more easily adapted to.
boilers of the ordinary construction.. Steam is usually superheated by passing
it through pipes that are exposed to a very considerable temperature in a fire.
or furnace adapted to the purpose. The steam in its passage through the
pipes abstracts caloric therefrom, and becomes. by that means superheated,

page_text: that is, it becomes charged with an additional quantity of caloric beyond that
to which its elastic pressure is due. An arrangement of tubes, such as is
usually employed for superheating steam, cannot, however, be always con-
veniently adapted to steam boilers, and, therefore, instead of causing the steam
to pass through a series of tubes to be superheated, I pass it through chambers
or boxes, which may be adapted in size and form to any convenient part of the
boiler, and may be heated by the flame come from the furnace or fire-place
before passing to the flue.
Supposing it be required to adapt my improvements to a tubular marine
boiler for example, I place a steam chest or chamber (having straight tubes
running from end to end thereof) in the passage from the fire-place or furnaco
to the chimney or funnel. The flame and heated gases pass through these
tubes and heat the steam that is passing through the chamber. In addition
to this superheating chamber, the steam may be passed through a series of
narrow boxes placed opposite to the ends of the tubular flues, and provided
with a number of short pipes, through which the flame and heated gases from
the tubular flues may be made to pass. Those boxes are to be connected
together in such a manner as to cause the steam to circulate therein in a
serpentine direction, so as to bring it in contact with as great an amount of
heating surface as possible.
From the last of the series of boxes the superheated steam is conducted to
the mixing chamber, where it is combined with common steam before being
passed into the cylinder of the engine.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said David Patridge in the Great Seal Patent Office on the
1st September 1857.
TO ALL TO: WHOM THESE PRESENTS SHALL COME, I, DAVID
PATRIDGE, of Woolwich, in tlio County of Kent, Engineer, send, greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of March, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her
reign, did, for Herself. Hér heirs and successors; give and grant unto me, the
said David 'Patridge, Her special license, that I, the said David Patridge; my
executors, 'administrators, and assigns, or such others as I, the said David.
Patridge, 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

page_text: 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 STEAM BOILERS,"
upon the condition (amongst others) that I, the said David Patridge, 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 David Patridge, 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, reference being bad to the Drawings hereunto annexed, and to the
letters and figures marked thereon (that is to say) :-
My Invention of "Improvements in Steam Boilers" relates to that descrip-
tion of steam boilers, or generators, in which superheated steam is produced for
the purpose of being used in combination with ordinary steam in marine, loco-
motive, and stationary engines. One of the principal objects. of my present
improvements is to construct and arrange the superheating apparatus, in such
a manner that it can be more conveniently employed for the intended purpose
than the ordinary superheating apparatus, and may be more easily adapted to
boilers of the ordinary construction. Steam is usually superheated by passing
it through pipes that are exposed to a very.considerable temperature in a flue or
a furnace adapted to the purpose. The steam in its passage through the pipes
abstracts caloric therefrom, and becomes by that means spperheated, that is,
it becomes charged with an additional quantity of caloric beyond that to which
its elastic pressure is due. An arrangement of tubes, such as is usually
employed for superheating steam, cannot, however, be always conveniently
adapted to steam boilers, and, therefore, instead of causing the steam to pass
through a series of tubes to be superheated, I pass it through chambers or
boxes, which may be adapted in size and form to any convenient part of the
boiler, and may be heated by the flame coming from the furnace or fire-place
before passing to the flue.
"
Supposing it be required to adapt my improvements to a tubular marine
boiler for example, I place a steam chest. or chamber (having straight tubes
running from end to end thereof) in the passage from the firé-place or furnace
to the chimney or funnel. The flame and heated gases pass through these
tubes and heat the steam that is passing through the chamber. In addition
to this superheating chambér, the steam may be passed through a series of

page_text: narrow boxes placed opposite to the ends of the tubular flues, and provided
with a number of short pipes, through which the flame and heated gases from
the tubular flues may be made to pass. These boxes are to be connected
together in such a manner as to cause the steam to circulate therein in a
serpentine direction, so as to bring it in contact with as great an amount of
heating surface as possible. From the last of the series of boxes the super-
heated steam may be conducted to a mixing chamber or slide jacket, where it
'may be combined with common steam before being passed into the cylinder of
the engine. This mixture of superheated steam with common steam does not,
however, form any part of the present Invention, which simply consists in a
novel construction or arrangement of boiler, in which steam may be super-
heated, or superheated steam may be produced, and which superheated steam
'when produced may be applied in any manner that may be desired.
.
In order, however, that my improvements in steam boilers may be more
clearly understood, I have shewn in the accompanying Drawings the arrange-
*ment and construction of parts which I prefer for effecting the object of my
-Invention.
Fig. 1 is a front elevation of my improved apparatus for obtaining super-
heated steam; Fig. 2 is a vertical section of the same, taken in the line A, B,
of Fig. 1; and Fig. 3 is a transverse section (at the line C, D, of Fig. 1).
a, a, is the case of the box through which the tubes b, b, pass; and I would
here state that I prefer to make the box of wrought iron or steel, but copper
or other suitable metal may be used. Fig. 4 is a vertical section; Fig. 5 is a
.transverse vertical section; and Fig. 6 is a plan of a tubular boiler, shewing
my improved apparatus for obtaining superheated steam applied thereto. In
this arrangement there are four boxes applied in the smoke box and one in the
up-take, but any other convenient number of boxes may be employed. c is
the pipe by which the steam is admitted into the first compartment of the box,
which is divided by vertical partitions d, d, into several compartments, which
are provided with outlets at e, e, to cause the steam to pass in a serpentine direc-
tion through the boxes; f.f.f.f, are pipes, by which the steam is conducted
from the upper part of one box to the other; and 9 is the pipe by which 'the
superheated steam is conveyed to the cylinder; or the pipe 9 may be connected
⚫to a mixing chamber, if preferred, so that common and superheated steam may,
if required, be used in combination.
Having now described my Invention of "Improvements in Steam Boilers,"
and having explained the means of carrying the same into effect, I would
observe that I lay no claim to the use of superheated steam, nor to the mix-
*ture of superheated with common steam for working engines, nor do I intend

page_text: to confine myself rigidly to the precise arrangement of parts herein shewn and
described, as they may perhaps be varied without departing from the nature of
my Invention; but what I claim, under the above in part recited Letters
Patent, is the mode of and apparatus for obtaining superheated steam, as above
set forth.
In witness whereof, I, the said David Patridge, have hereunto set my
hand and seal, the Twenty-eighth day of August, in the year of our
Lord One thousand eight hundred and fifty-seven.
> Witness,
J. W. MOFFATT,
66, Chancery Lane.
D. PATRIDGE. (L.S.)