IMPROVEMENTS IN STEAM GENERATORS."
Year: 1864

page_text: LETTERS PATENT to James Garth Marshall, of Leeds, in the County of
York, Flax Spinner, for the Invention of "IMPROVEMENTS IN STEAM
GENERATORS."
PROVISIONAL SPECIFICATION left by the said James Garth Marshall
at the Office of the Commissioners of Patents, with his Petition, on
the 18th June 1864.
I, JAMES GARTH MARSHALL, of Leeds, in the County of York, Flax Spinner,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
STEAM GENERATORS," to be as follows:-
My Invention of improvements in steam generators has for its object to
produce a perfect circulation of the water in the steam boiler, so that the
steam immediately it is generated may at once escape from the surrounding
water and reach the steam space above. By a proper circulation of the
water the colder portions thereof will be brought into contact with the
hollow parts of the steam generator, and steam will be more rapidly generated
than in boilers of the ordinary construction.
In carrying out my Invention I take any convenient number of tubes,
according to the capacity of the boiler, and I convert them into separate
syphons, (that is, the tubes are bent,) and the open end of one leg commu-
nicates with the lower part of the boiler, while the open end of the other
leg communicates with the steam space, or with a higher level of the boiler.

page_text: The bent parts of the tubes project downwards into the fire space of the
furnace, and are thus subjected to great heat. By reason of the difference
in level of the two open ends of the syphon tube a rapid circulation of the
water is maintained.
As a modification of the above, instead of employing bent tubes converted
into syphons as above set forth, I make use of a series of single straight
vertical tubes, divided down the centre by a partition into two channels,
which are open at the upper end, but at different levels. The lower ends
communicate under the partition, so that there will be an upward and down-
ward current on opposite sides of the central partition. These vertical tubes
project down from the lower part of the boiler into the fire space precisely as
the syphon tubes above mentioned.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Garth Marshall in the Great Seal Patent Office on
the 13th December 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
GARTH MARSHALL, of Leeds, in the County of York, Flax Spinner, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of June, in the year of our Lord One
thousand eight hundred and sixty-four, in the twenty-seventh year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
James Garth Marshall, Her special license that I, the said James Garth
Marshall, my executors, administrators, and assigns, or such others as I, the
said James Garth Marshall, 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 "IMPROVE-
MENTS IN STEAM GENERATORS," upon the condition (amongst others) that I, the
said James Garth Marshall, 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.

page_text: NOW KNOW YE, that I, the said James Garth Marshall, 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 had to the Drawing 'hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
My Invention of "Improvements in Steam Generators" has for its object
to produce a perfect circulation of the water in the steam boiler or generator,
so that the steam immediately it is generated may at once escape from the
surrounding water and reach the steam space above. By a proper circulation
of the water the colder portions thereof will be brought into contact with the
hollow parts of the steam generator exposed to the fire or heated gases,
and steam will be more rapidly generated than in boilers of the ordinary
construction.
In the accompanying Drawing I bave shown several methods of effecting
the object of my Invention.
Fig. 1 is a plan view, and Fig. 2 a side elevation, representing one of my
improved modes of constructing steam generators. In this instance the
boiler is constructed of a series of syphon tubes secured in any suitable
manner in a horizontal plate. Any convenient number of tubes according to
the capacity of which it is desired to make the boiler may be used, and these
tubes are converted into separate syphons, as shewn in the Figures, that is, the
tubes are bent, and are made with legs of different lengths, the open end of
one leg a being made to communicate with the lower part of the boiler A,
while the open end of the other leg a¹ communicates with the steam space, or
with a higher level of the boiler. The bent parts of the tubes pass through
the tube plate b, which forms the lower part of the boiler, and they project
downwards into the fire space of the furnace B, and are thus subjected to
great heat. By reason of the difference in the length of the legs a, a¹, of
the syphon tubes, and the consequent difference in the level of the two open
ends of the syphon tube, a rapid circulation of the water is maintained, as
the cooler particles of water will pass down the shorter leg of the syphon,
while the steam will rise up the longer leg.
Fig. 3 is a plan view, and Fig. a vertical section, representing another
method of effecting the object of my Invention. In this instance, instead of
employing bent tubes converted into syphons as above set forth, I make use
of a series of single straight vertical tubes c, c', which are divided down the
centre by a partition d, into two channels c and c¹; both of which are open at
the upper end, but at different levels, as shown at Fig. 4. The two channels

page_text: c and c¹ communicate at their lower parts under the partition d, so that there
will be an upward and downward current on opposite sides of the central
partition, as indicated by the arrows. These vertical tubes project down from
the tube plate B at the lower part of the boiler into the fire space precisely as
the syphon tubes above mentioned. In order to cause the particles of steam
as they are formed to pass up the proper channel, as indicated by the arrows,
the lower end of the diaphragm or partition d should be bent on one side, as
shown at 1 in Fig. 4. This will generally be found sufficient to direct the
steam into the proper channel, and this may be still further ensured by making
transverse openings in the partition, and adapting thereto deflecting plates as
at 2, 2, in Fig. 4. In constructing boilers with these divided tubes, it will
be found advisable to arrange the several rows of tubes in such a manner that
the descending channels of two neighbouring tubes should be opposite to each
other, and the ascending channels of the tubes shall be opposite to ascending
channels of other tubes, as seen best in Fig. 6, which is a sectional plan view
of a square upright boiler constructed according to my Invention. Fig. 5 is
a vertical section of the same. It will be seen that the fire-place C is sur-
rounded by a water space D, which is divided by a vertical partition d into
two channels for ascending and descending currents precisely as in the tubes,
the partition d¹ being also provided with lateral openings at its lower part,
and deflecting plates to direct the steam into the ascending channel; E is the
fire-door of the furnace, and F the exit flue communicating with a flue which
surrounds the boiler, and into which the gases after they have circulated
among the tubes a, a, pass. The feed water may be supplied to the narrow
water space surrounding the boiler, or to any other convenient part of the
apparatus; or some tubes connected with the boiler may be placed in the flue
in order to intercept any heat that may have a tendency to pass off in that
direction, and the feed water may, if desired, be made to pass through such
tubes before it enters the body of the boiler. Fig. 7 is a sectional view, and
Fig. 8 a side elevation, representing a modification of the plan just described.
In this instance, instead of tubes divided by a central partition, I employ long
narrow chambers or leaves, which, however, are divided by means of a central
partition d, as in the tubes of Figures 3 and 4, into two channels, an ascending
and a descending one. It will be seen that in all the several modifications
the ascending channel is carried up a considerable distance above the open
end of the descending channel, and therefore the issue of the steam from the
open end of the ascending channel will not disturb the water about the open
end of the descending channel. I would observe that any convenient number

page_text: of tubes such as those above described may be adapted to some kinds of
existing boilers, and will be found to economize the heat and materially assist
in generating steam in such boilers.
Having now described my Invention of improvements in steam generators,
and having explained the manner of carrying the same into effect, I claim
as the Invention secured to me by Letters Patent as aforesaid, the mode
herein set forth of producing a circulation of the water in steam boilers,
so that the steam immediately it is generated may at once escape from the
surrounding water and reach the steam space above.
In witness whereof, I, the said James Garth Marshall, have hereunto
set my hand and seal, the Twelfth day of December, in the year of
our Lord One thousand eight hundred and sixty-four.
J. G. MARSHALL. (L.S.)