IMPROVEMENTS IN THE FORM AND ARRANGEMENT OF STEAM BOILERS AND OF TUBES FOR THE SAME, FOR THE RAPID PRODUCTION OF STEAM, FOR PROLONGING THEIR DURABILITY WITHOUT THE RISKS OF EXPLOSION OFTEN ARISING FROM THE IRREGULAR DISTRIBUTION OF THE HEAT, ALSO FOR EFFECTING ECONOMY OF FUEL
Year: 1874

page_text: ETTERS PATENT to Alfred de Pindray, Civil Engineer, of No. 1,
Victoria Street, Westminster, in the County of Middlesex, for the
Invention of "IMPROVEMENTS IN THE FORM AND ARRANGEMENT OF STEAM
BOILERS AND OF TUBES FOR THE SAME, FOR THE RAPID PRODUCTION OF STEAM,
FOR PROLONGING THEIR DURABILITY WITHOUT THE RISKS OF EXPLOSION OFTEN
ARISING FROM THE IRREGULAR DISTRIBUTION OF THE HEAT, ALSO FOR
EFFECTING ECONOMY OF FUEL."
Sealed the 19th February 1875, and dated the 21st August 1874.
PROVISIONAL SPECIFICATION left by the said Alfred de Pindray at the
Office of the Commissioners of Patents, with his Petition, on the
21st August 1874.
I, ALFRED DE PINDRAY, Civil Engineer, of No. 1, Victoria Street,
3 Westminster, in the County of Middlesex, do hereby declare the
"IMPROVEMENTS IN THE FORM AND
nature of the said Invention for
ARRANGEMENT OF STEAM BOILERS AND OF TUBES FOR THE SAME, FOR THE RAPID

page_text: mounted in order to obtain all the advantages of the economy which
they ought to give.
My improvements when applied to these three kinds of boilers above
mentioned are as follows: —
Firstly. Steam boilers with little multiple internal tubes for steamers,
locomotives, &c., will have as usual a cylindrical or square form, but
they differ entirely in their system of tubes, which will be in all cases
of conical form and of an internal area determined by the proportions
of one-quarter to one-third more at the exit than at the entrance, so as
to permit a constant draught of the gases, in other terms to replace the
velocity of the draught by the area, or to gradually increase the section
of the tube in proportion to the slackening speed of the gases. Tho
chamber called the gas chamber at the rear of the boiler will have two
empty areas in addition to the empty area of all the tubes united taken
at their inlet into the said gas chamber. The smoke box placed in
front or above the fire-place will have an internal area of one-fifth
more than that of all the tubes united at their inlet in the side smoke
box.
Secondly. The cylindrical generators with one or several large interior
tubes (known as Cornish boilers) will be provided with one or several
tubes of conical form, the internal area being determined in the
proportion of from one-fourth to one-third more at the outlet than at
the inlet, and leading into the smoke box. These conical tube or tubes
are of a length less than that of the boiler in consequence of the smoke
box being contained within the former. The smoke box established
upon the front, starting from the level of the conical tube or tubes,
will have one-fifth of internal area more than that of the tube or tubes
altogether. The bottom of the said smoke box and its two sides are
constructed so as to contain a volume of water, which will be in direct
communication with the body of the generator, so as to utilize as heating
surface the greater part of the smoke box.
Thirdly. The boiler with one or more vessels and a body (known
generally in England as the elephant boiler) will be constructed in the
following manner :- The two vessels are separated one from another for
their whole length by 3 or 4 inches; they are connected to the body of
the boiler, following its length by one or several short oblong or oval

page_text: communications, rivetted and adjusted solidly, half to the boiler body,
and half to the vessels, so to overlap one another. The vessels' com-
munications will be of a less diameter than those of the boiler, so as to
allow them to overlap, and they are about an inch or more in length in
order to be keyed into the interior of the boiler.
Each communication after its adjustment will be provided with two
or three rivets at its extremities in order to augment the solidity against
the vibrations of the water in ebullition.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alfred de Pindray in the Great Seal Patent Office
on the 20th February 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
DE PINDRAY, Civil Engineer, of No. 1, Victoria Street, Westminster, in
the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of August, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Alfred de Pindray, Her special
licence that I, the said Alfred de Pindray, my executors, administrators,
and assigns, or such others as I, the said Alfred de Pindray, 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 FORM AND ARRANGEMENT OF STEAM BOILERS AND OF TUBES FOR THE SAME, FOR
THE RAPID PRODUCTION OF STEAM, FOR PROLONGING THEIR DURABILITY WITHOUT THE
RISKS OF EXPLOSION OFTEN ARISING FROM THE IRREGULAR DISTRIBUTION OF THE
HEAT, ALSO FOR EFFECTING ECONOMY OF FUEL," upon the condition (amongst
others) that I, the said Alfred de Pindray, my executors or admini-
strators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the

page_text: 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 Alfred de Pindray, 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 thereof, that is to say:―
This Invention relates to a system or plan for improving the arrange-
ment of steam boilers and of tubes for boilers for the purposes set forth
in the title above.
The system can be applied to all kinds of boilers actually in use, but
it is specially applicable to the three sorts of boilers most generally in
use, which are the following:-
:―
1st. The boilers with little tubes for steamers, locomotives, verticals,
and others of the tubular class.
2ndly. The cylindrical boiler with one or several large interior tubes
known under the names of Cornish boilers and Lancashire boilers.
3rdly. The boiler with one or two vessels or large tubes within the
furnace, such as are called in England elephant boilers.
My Invention gives to steam generators an altogether new form in its
application as well in the details of its construction as in the complete
boiler. It is from this form established upon mathematical bases that
a real heating surface is obtained, and consequently an effective
3 vapourization by reason of the equal distribution of the heat.
Steam boilers connected to or arranged according to my system should
be invariably heated beneath with the object of utilizing in the first
portion of the course all the most powerful caloric which the combustible
has produced. They can be heated by any system of ordinary furnace,
but the greatest advantage will be obtained by heating them with my
system known as "the De Pindray."
If I recommend in preference to all others my.system of furnace for
my improvements in boilers it is firstly because of the powerful heat

page_text: UL The gas WHICH the combustible produces, and also because of the
mathematical corrclation with my improvements in boilers, which
besides, are of an altogether special and peculiar form, to be thus
mounted in order to obtain all the advantages of the economy which
they ought to give.
My improvements when applied to these three kinds of boilers above
mentioned are clearly shown in the accompanying Drawings.
1stly. Steam boilers A, with little multiple internal tubes B, as shown
in Figures 1, 2, and 3, which are a longitudinal section, a section through
the smoke box, and an end view respectively for steamers, loco-
motives, &c., have as usual a cylindrical or square form, but they differ
entirely from ordinary tubular boilers in their system of tubes, which
are in all cases of taper or conical form, as clearly seen in Figure 1, and
of an internal area determined by the proportions of one quarter to one
third more at the exit than at the entrance, so as to permit a constant
draught of the gases, in other terms to replace the velocity of the draught
by the area or to gradually increase the section of the tube in proportion
to the slackening speed of the gases. The chamber called the gas
chamber, sometimes built at the rear of the boiler, though not shown
in the Drawings, has two empty areas in addition to the empty area of
all the tubes united taken at their inlet into the said gas chamber. The
smoke box C placed in front or above the fire-place has an internal area
of one-fifth more than that of all the tubes united at their inlet in the
smoke box.
2ndly. The cylindrical generators A, with one or several large interior
longitudinal tubes B (known as Cornish boilers) as clearly illustrated in
Figures 4, 5, and 6, in which Figure 4 is a longitudinal section, Figure 5,
a section through the smoke box, and Figure 6, a section through the
after end of a Cornish, made in accordance with my Invention, is pro-
vided with one or several interior tubes B of conical or taper form, the
internal area of the tube or tubes being determined in the proportion of
from one-fourth to one-third more at the outlet or smoke box end than
at the inlet or after end, and leading into the smoke box. These conical
or taper tube or tubes B are of a length less than that of the boiler A in
consequence of the smoke box being contained within the former. This
is clearly shown in Figure 4. The smoke box fitted at the front portion,

page_text: starting from about the level of the bottom D of the taper or conical
tube or tubes B, has one-fifth of internal area more than that of the
longitudinal tube or tubes altogether. The bottom E of the said smoke
box B and its two sides F are constructed so as to be surrounded by a
volume of water which is in direct communication with the body of the
generator so as to utilize as heating surface the greater part of the smoke
box B.
3rdly. The boiler and details shown in Figures 7, 8, 9, and 10, with
one or more vessels and a body (known generally in England as the
elephant boiler) is constructed in the following manner:-The two
vessels G, G, are separated one from another for their whole length by
3 or 4 inches. They are connected to the body A of the boiler, following
its length by one or several short oblong or oval communications H, H,
rivetted and adjusted solidly by a rust joint, half to the boiler body A
and half to the vessels G, so as to overlap one another, as particularly
shown in Figure 9. The vessel communications H are of a less diameter
than those of the boiler so as to allow them to overlap, and they penetrate
about an inch or more into the interior of the boiler in order to be
keyed, flanged, or rivetted in.
Each communication after its adjustment is provided with two or
three rivets at its extremities in order to augment the solidity against
the vibrations of the water in cbullition.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,―
The several improvements herein-before described as and for the
purposes set forth.
Secondly. The form and arrangement of boilers for steamers, loco-
motives, and other purposes, and the fitting of taper tubes as return
flues therein, such tubes having their larger diameter ends nearest the
chimney or smoke box as and for the purposes set forth.
Thirdly. The construction of cylindrical boilers with one or more
tapered tubes (round or oval) fitted therein, such tube or tubes acting
as return flues, and with their larger ends nearest the smoke box, for the
purposes set forth and substantially as shown in the Drawings.

page_text: Fourthly. The construction of boilers of the elephant type, with
short connections of oblong or oval shape, such connections having
overlap and rust joints, as set forth.
In witness whereof, I, the said Alfred de Pindray, have here-
unto set my hand and scal, this Twentieth day of February,
One thousand eight hundred and seventy-five.
Witness,
E. DE LARIERE.
ALFRED DE PINDRAY. (L.S.)