Improvements IN STEAM BOILERS
Year: 1874

page_text: LETTERS PATENT to William Alexander Sanderson, Robert Sanderson,
and James Sanderson, all of the Firm of R. and A. Sanderson and
Company, of Gala Mills, Galashiels, in the County of Selkirk,
PROVISIONAL SPECIFICATION left by the said William Alexander
Sanderson, Robert Sanderson, and James Sanderson at the Office
of the Commissioners of Patents, with their Petition, on the
22nd June 1874.
We, WILLIAM ALEXANDER SANDERSON, ROBERT SANDERSON, and
JAMES SANDERSON, all of the Firm of R. and A. Sanderson and
Company, of Gala Mills, Galashiels, in the County of Selkirk, Scotland,
do hereby declare the nature of the said Invention for "Improvements
IN STEAM BOILERS," to be as follows:-
$6
Our improvements relate to that description of steam boilers known
as "French" or clephant" boilers, in which one or more cylindrical
upper compartments are connected to one or more lower cylindrical

page_text: compartments by means of vertical water tubes, the furnace being
placed in the space between the upper and lower compartments.
According to our present improvements we construct the lower com-
partments of such boilers with internal return flues, so that the products
of combustion, after passing from the furnace to the back end of the
boiler in the space or flue between the upper and lower compartments,
are made to return through the said internal flue of the lower compart-
ment to the front end of the boiler again, whence they pass to the
chimney. We arrange such internal flues to slope up from the back
end to the front end of the compartment, and at the front end we make
the flue of a conically reduced form so as to obtain room for a man-hole
in the end surface of the compartment beneath the flue without
having to increase the diameter of the compartment unduly for this
purpose.
In the internal flue we fix transverse conical water tubes arranged in
such varying positions one behind the other that their points of con-
nection to the flue tube are situated in helical lines extending from one
end of the flue tube to the other, so that the products of combustion
in passing through the flue tube impinge against and circulate round
the conical water tubes, and are at the same time thrown with greater
force against the sides of the flue tube.
1
In some cases we provide, in addition to the above described internal
return flue of the lower compartments, external return flues, so that the
products of combustion passing part along the internal flue and in part
along the external flues, and in such external flues we provide shutters
or flaps hinged to the flue, and capable of being moved by rods or chains
so as to close the area of the flue more or less, thus acting as dampers to
regulate the draught, and at the same time serving to keep the hot gases
more intimately in contact with the boiler surface. We are also enabled
by the use of these shutters to make external flues of a commodious size
for cleaning purposes without loss of heat, the gases passing through
them being kept by the shutters close to the boiler surface.
"
In constructing such "French
$6
or elephant" boilers to withstand
extreme pressures, or when there is an extra large number of tubes we
strengthen the shell of the boiler by extending the flanges of the water
tubes so as to overlap each other, the overlapping parts being secured to
each other and to the shell of the boiler by the same rivets, additional

page_text: strength being given when necessary by transverse stays between the
tubes.
In employing these boilers for marine purposes we provide in the
upper compartments transverse and longitudinal division plates. By
means of these division plates the lashing of the water in the boiler
when the vessel rolls or pitches is to a great extent prevented.
A communication between the several spaces enclosed by the said
division plates is established by means of the conical water tubes that
connect the upper compartments of the boiler with the lower com-
partments.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said William Alexander Sanderson, Robert Sanderson,
and James Sanderson in the Great Seal Patent Office on the
3rd December 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
ALEXANDER SANDERSON, ROBERT SANDERSON, and JAMES SANDERSON,
all of the Firm of R. and A. Sanderson and Company, of Gala Mills,
Galashiels, in the County of Selkirk, Scotland, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of June, 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 successors,
give and grant unto us, the said William Alexander Sanderson, Robert
Sanderson, and James Sanderson, Her special license, that we, the
said William Alexander Sanderson, Robert Sanderson, and James
Sanderson, our executors, administrators, and assigns, or such others
as we, the said William Alexander Sanderson, Robert Sanderson,
and James Sanderson, our 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 law-
fully 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 we, the said William Alexander Sanderson,

page_text: Robert Sanderson, and James Sanderson, our executors or admini-
strators, by an instrument in writing under our, or their hands and. seals,
or under the hand and seal of one of us or them, 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 Robert Sanderson, on behalf of
myself and the said William Alexander Sanderson, and James Sanderson,
do hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, reference being had
to the accompanying Sheets of Drawings, and to the figures and letters
marked thereon, that is to say :-
as
"
Our improvements relate to that description of steam boilers known
"French" or elephant" boilers, in which one or more cylindrical
upper compartments are connected to one or more lower cylindrical
compartments by means of vertical water tubes, the furnace being
placed in the space between the upper and lower compartments.
According to our present improvements we construct the lower com- 2
partments of such boilers with internal return flues, so that the products
of combustion, after passing from the furnace to the back end of the
boiler in the space or flue between the upper and lower compartments,
are made to return through the said internal flue of the lower compart-
ment to the front end of the boiler again, whence they may either pass
to the chimney direct or may be led to the back end of the boiler by
flues outside the lower compartment of the boiler. We arrange such
internal flues to slope up from the back end to the front end of the
compartment, and at the front end we make the flue of a conically
reduced form so as to obtain room for a man-hole in the end surface of
the compartment beneath the flue without having to increase the
diameter of the compartment unduly for this purpose.
In the internal flues we fix transverse water tubes, which may be
conical, arranged in such varying positions one behind the other that
their points of connection to the flue tube are situated in helical lines a
extending from one end of the flue tube to the other, so that the
products of combustion in passing through the flue tube impinge against

page_text: cylindrical compartments, two above and two below, with our improve-
ments applied thereto; and Fig. 8 represents a sectional plan through
the flue chamber between the upper and lower compartments. In those
Figures the same letters of reference are employed to indicate like parts.
It will be seen that each of the lower compartments L is made accord-
ing to our present Invention, with an internal flue F sloping upwards
towards the front and conically reduced at the front end as shown at F',
so as to afford room for a man-hole M under the flue without the
necessity for increasing the size of the compartment for that purpose.
The internal flue F is crossed at various angles by a number of water
tubes T, the junctions of the successive tubes to the flue being arranged
in a helical line so that the products of combustion passing along the
flue impinge against and circulate round each tube in succession; E are
external flues formed at the sides and underneath the lower compart-
ments; L and S are shutters or flaps hinged to the base of the flue and
worked by a chain C, which may be led to any convenient point outside
the flue so that the shutters S can be raised or lowered as required. The
external flues E being made sufficiently large to give convenient access
for cleaning the shutters S when they are partially raised, as shewn in
Fig. 2, reduce the area of passage for the hot gases and cause them to
impinge against the surface of the boiler as described above.
Fig. 9, Sheet I., represents by a plan view several of the water tubes
W that connect the upper and lower compartments of clephant
boilers, shewing the mode in which we connect these tubes to the shell
of the boiler for the purpose of giving strength. Every alternate tube
is made with a flange A extending on each side so as to come under or
be overlapped by the flange of the tube next in order so that in rivetting
the latter flange to the shell of the boiler the rivets are passed through
both flanges. The upper compartments U of elephant boilers when such
boilers are used at sea we make with transverse and longitudinal
partitions P, which, while they have the effect of strengthening the
boiler prevent the lashing of the water. Complete communication
between the spaces into which the compartment is thus divided is
maintained through the water tubes W that connect it with the com-
parment below. In the sectional plans, Figs. 4 and 8, we have shewn
these tubes arranged in zig-zag order, and the flue through which they
pass constructed with sides of undulating form as described in the
Specification of a Patent granted to us on the 31st October -1873;

page_text: No. 3546, such arrangements of tubes and form of flue causing the hot
gases to impinge more effectually on the surface of the tubes. This
arrangement and construction form no part of our present Invention,
which, as may readily be understood, can be applied to boilers of the
elephant kind when the water tubes are otherwise arranged.
No. 3546, such arrangements of tubes and form of flue causing the hot
gases to impinge more effectually on the surface of the tubes. This
arrangement and construction form no part of our present Invention,
which, as may readily be understood, can be applied to boilers of the
elephant kind when the water tubes are otherwise arranged.
Having thus described the nature of our Invention, and in what
manner the same is to be performed, we claim,--
First. The construction of the lower compartments of elephant
boilers with internal flues crossed by transverse water tubes, substan-
tially as herein described.
Second. The use in the flues of elephant boilers of flaps or shutters
for regulating draught and for keeping the hot gases close to the boiler
surface, substantially as herein described.
Third. The method substantially as herein described of strengthening
the shells of elephant boilers where they are pierced for the water tubes
by overlapping the flanges of those tubes.
Fourth. The use for marine elephant boilers of partitions in their
upper.compartments to diminish lashing of the water therein, substan-
tially as herein described.
In witness, whereof, I, the said Robert Sanderson, have hereunto
set my hand and seal, this First day of December, in the
year of our Lord One thousand eight hundred and seventy-
four.