IMPROVEMENTS IN STEAM BOILERS.
Year: 1868

page_text: LETTERS PATENT to John Smith and James Dewdney, both of
No. 27, Leadenhall Street, in the City of London, for the Invention
of "IMPROVEMENTS IN STEAM BOILERS.".
Sealed the 16th March 1869, and dated the 18th September 1868.
PROVISIONAL SPECIFICATION left by the said John Smith and James
Dewdney at the Office of the Commissioners of Patents, with their
Petition, on the 18th September 1868.
We, JOHN SMITH and JAMES DEWDNEY, both of No. 27, Leadenhall
Street, in the City of London, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN STEAM BOILERS," to be as follows:-
Our Invention has reference to that description of steam boilers in
which pendant water tubes are employed containing an inner tube for
effecting the circulation of the water.
Our present improvements have for their object, firstly, to separate
more effectually than has hitherto been done the water charged with
steam that rises from the outer tubes from the water that passes down
the inner tubes; and secondly, to prevent the sediment or solid matter

page_text: contained in the water from choking up the tubes as is the case with the
present arrangements.
For these purposes in one arrangement we extend the inner tubes some
distance above the upper ends of the outer tubes, and we connect them
all together by means of a solid plate or diaphragm, in which such inner
tubes are firmly secured either flush with the plate or projecting above
the same if required. In the said plate may be formed other apertures
in which may be fixed other tubes passing up to, above, or below the
water level for facilitating the conveyance of the steam to the steam
spaces of the boiler. The said plate will also serve to prevent priming
and to receive some of the solid matter contained in the water, thus
preventing to a certain extend the deposit of such matters in the
tubes. The plate may be flat or convex, and may be formed in segments,
or with ribs or corrugations, in order to throw off the sediment into the
water spaces near the shell of the boiler.
In another arrangement we carry the outer tubes up 'above the crown
plate to the before-mentioned plate or diaphragm in which they are fixed
either flush or so as to project above the same, and we form the upper
ends of the inner tubes with a bend passing through the outer tubes at a
point between the crown plate and upper plate. By this means any
solid matter that is carried up in the outer tubes is allowed to deposit
on the upper plate, and is thus prevented from passing into the tubes
again.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Smith and James Dewdney in the Great 2
Seal Patent Office on the 17th March 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
SMITH and JAMES DEWDNEY, both of No. 27, Leadenhall Street, in the
City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 3
Letters Patent, bearing date the Eighteenth day of September, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said John Smith and James Dewdney, Her
special licence that we, the said John Smith and James Dewdney, our 3

page_text: executors, administrators, and assigns, or such others as we, the said
John Sinith and James Dewdney, 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 '
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 we, the said John Smith and James
Dewdney, our executors or administrators, 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 John Smith, on behalf of myself
and the said James Dewdney, do hereby declaro the nature of the said
Invention, and in what manner the same is to be performed, to he
particularly described and ascertained in and by the following statement.
thereof, reference being had to the accompanying Sheet of Drawings,
and to the figures and letters marked thereon, that is. to say:-
Our Invention has reference to that description of steam boilers in
which pendant water tubes are employed containing an inner tube for
effecting the circulation of the water.
Our prosent improvements have for their object, firstly, to soparate
more effectually than has hitherto been done the water charged with
steam that rises from the outer tubes from the water that passes down
the inner tubes; and secondly, to prevent the sediment or solid matter
contained in the water from choking up the tubes as is the case with the
present arrangements.
For these purposes in onc arrangement we extend the inner tubes
some distance above the upper ends of the outer tubes, and we connect
them all together by means of a solid plate or diaphragm, in which such
inner tubes are firmly secured either flush with the plate or projecting
above the same if required. In the said plate may be formed other
apertures, in which may be fixed other tubes passing up to above or
below the water level for facilitating the conveyance of the steam to
the steam spaces of the boiler. The said plate will also serve to prevent

page_text: priming, and to receive some of the solid matter contained in the water,
thus preventing to a certain extent the deposit of such matters in the
tubes. The plate may be flat or convex, and may be formed in segments,
or with ribs or corrugations, in order to throw off the sediment into the
water spaces near the shell of the boiler.
In another arrangement we carry the outer tubes up above the crown
plate to the before-mentioned plate or diaphragm in which they are fixed
either flush or so as to project above the same, and we form the upper
ends of the inner tubes with a bend passing through the outer tubes
at a point between the crown plate and upper plate. By this means
any solid matter that is carried up in the outer tubes is allowed to
deposit on the upper plate, and is thus prevented from passing into the
tubes again.
Figures 1 and 2 on the accompanying Sheet of Drawings shew
respectively a vertical section and a sectional plan on line X, X,
Figure 1, of an upright boiler with one arrangement of our Invention
applied thereto.
The outer tubes A, A, of the pendant tubes are secured to the crown
plate B in the usual manner, while the inner tubes C, C, are continued
some distance above the level of the crown plate and are fixed in
apertures in the plate or diaphragm D, formed by preference of flanged
segments of cast iron secured together and supported at its circumference
upon an angle iron F rivetted to the sides of the boiler as shewn. This
diaphragm has apertures or notches d, d, at its circumference, and has
other apertures d', d¹, formed with tubular projections in intermediate
positions between the tubes C, C, which apertures d and d¹ serve to allow
the steam passing up together with the water from the outer tubes into
the spaces between the crown plate B and the diaphragm D to escape
thence into the steam space above; the diaphragm D is also provided
with other holes at d³, d³, through which the stays E supporting the
crown plate B pass. The other parts of the boiler are of usual con-
struction and require no further description.
Figure 3 shews a part sectional elevation of another arrangement in
which the outer tubes A. are continued up through the crown plate B,
and are secured to the diaphragm, while the inner tubes C being formed
with a bend C¹ pass through an aperture in the outer tube A situated
between the crown plate B and diaphragm D. Thus any sediment that
is carried up through the outer tubes will be deposited upon the

page_text: diaphragm D, and be prevented from passing into the side openings of
the inner tubes.
Having thus described the nature of our Invention, and in what
manner the same is to be performed, we wish it to be understood that
what we claim is,―
First. The arrangement of pendant water tubes wherein the inner
tubes are extended beyond the crown plate of the boiler, and pass through
a plate or diaphragm fixed or supported a certain distance above the
crown plate, and provided with apertures for the passage of steam and
water, substantially as and for the purposes set forth.
Second. The arrangement of pendant water tubes wherein the outer
tubes are extended beyond the crown plate of the boiler, and pass
through a plate or diaphragm situated a certain distance above the
crown plate, the inner tubes being formed with a bend passing through
the sides of the outer tubes at a point between the crown plate and
diaphragm, substantially as and for the purposes set forth.
In witness whereof, I, the said John Smith, have hereunto set my
hand and seal, this Seventeenth day of March, in the year of our
Lord One thousand eight hundred and sixty-nine.
JOHN SMITH. (L.S.)