IMPROVEMENTS IN THE CONSTRUCTION OF THE An D DATA A
Year: 1856

page_text: LETTERS PATENT to William Watson Hewitson, of Headingley, near
Leeds, and William Hamond Bartholomew, of 15, Brunswick Terrace,
Leeds, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF THE
An D DATA A
PROVISIONAL SPECIFICATION left by the said William Watson Hewitson
and William Hamond Bartholomew at the Office of the Commissioners
of Patents, with their Petition, on the 5th June 1856.
We, WILLIAM WATSON HEWITSON, of Headingley, near Leeds, and WILLIAM
HAMOND BARTHOLOMEW, of 15, Brunswick Terrace, Leeds, do hereby declare
the nature of the Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF THE
FURNACES OR FIRE BOXES OF TUBULAR STEAM BOILERS," to be as follows:-
'
This Invention has for its object improvements in the construction of the
furnaces or fire boxes of tubular steam boilers. For these purposes the fire box
or furnace is constructed within a horizontal cylinder. The fire bars are of
the ordinary construction, having below them a space or ash-pit, below which
is an enclosed air passage, by which air is conducted to a chamber at the back
end of the cylinder, where there is a plate on hinges, such plate being per-
forated with numerous holes. At the back end of the fire bars is a fire clay
bridge, which, by preference, is formed curved and convex at top; beyond this
bridge there is a hanging bridge from the upper part of the cylinder, within

page_text: which the furnace is constructed, and it is preferred that the lower part of
such hanging bridge should be curved and concave. Beyond this hanging
bridge is the end of the cylinder, so that there is a chamber or space beyond
the two bridges. The tubes constituting the numerous flues of the boiler are
fixed into the end of the cylinder, and the cylinder is (as well as the tubular
flues) surrounded by the water in the boiler. Provision may be made for
introducing streams of air at or near the front of the furnace or fire box, so
that such streams of air may pass over the fuel on the fire bars.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Watson Hewitson and William Hamond Bartholomew
in the Great Seal Patent Office on the 5th December 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
WATSON HEWITSON, of Headingley, near Leeds, and WILLIAM IIAMOND
BARTHOLOMEW, of 15, Brunswick Terrace, Leeds, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by IIer Letters
Patent, bearing date the Fifth day of June, in the year of our Lord One
thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
William Watson Hewitson and William Пamond Bartholomew, Her special
licence that we, the said William Watson Hewitson and William Hamond
Bartholomew, our executors, administrators, and assigns, or such others as we,
the said William Watson Hewitson and William Hamond Bartholomew, 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 THE CONSTRUCTION OF THE
FURNACES OR FIRE BOXES OF TUBULAR STEAM BOILERS," upon the condition
(amongst others) that we, the said William Watson Hewtson, and William
Hamond Bartholomew, 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.

page_text: NOW KNOW YE, that I, the said William Watson Hewitson, on behalf
of myself and the said William Hamond Bartholomew, do hereby declare the
iature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:
!
This Invention has for its object improvements in the construction of the
furnaces or fire boxes of tubular steam boilers. For these purposes the firo
box or furnace is constructed within a horizontal cylinder, as shown in the
Drawing. The fire bars are of the ordinary construction, having a contrivance
for withdrawing the supporting bar at the front end, the object being to provide
means for dropping the fire bars in case of necessity. Below the fire bars is a
space or ash-pit, and below this there is an enclosed space or air passage, made
of cast or wrought iron, and forming, when in its place, the means of admitting
cold air into the combustion chamber, in which is the hanging bridge No. 2,
herein-after described. This iron box or air passage, the bottom of which is
made circular to fit the curve of the horizontal cylinder in which the furnace
is constructed, and the top of which forms the bottom of the ash-pit, is mado
tight, except at the inside and next the combustion chamber, across which is
fixed or suspended a plate perforated with small holes, and at the outside end
next the firing stage at which a valve or slide is fixed, so as to regulate the
quantity of cold air admitted to the combustion chamber, or to shut it off com-
pletely. At the end of the fire bars and furthest from the fire door is a fire-
brick bridge, built across the furnace, between which, and the ends of the fire
bars or cross bearer, is an air space of about three-fourths of an inch. In the
construction of this fire-brick bridge, which we will call No. 1, it is preferred
to have the face next the fire bars vertical, or nearly so, and to have the top
edge, or part nearest to the top of the horizontal cylinder, curved and convex;
it is also preferred to have the inside face of this bridge, and which is nearest
to the tube plate, inclined, at the rate of about one in three, so that the bottom
part may be nearer to the tube plate than what the top part or curved and
convex edge is. This bridge is intended to be built or placed upon an iron
cross bar or bearer, the under side of which is level across from side to side,
but rather lower along the bottom edge, which is next to the tube plate, than it
is at the contrary edge, which is intended to be immediately underneath the
vertical face of the bridge No. 1. This is for the purpose of more readily
making a tight joint between the under side of the iron cross bar or bearer
and the top part of the inside end of the iron box or air passage, for the supply
of air to the combustion chamber. It is intended that the perforated plate
placed across the end of this iron-box or air passage shall be. nearly the same

page_text: distance from the tube plate when in its proper place as the bottom inside
edge of the fire-brick bridge No. 1, only that it is preferred to have it inclined,
so that the top edge nearest to the iron cross bar or bearer is about one inch
nearer to the tube plate than what the bottom edge is; and it is also intended
that the top part of the iron box or air passage should be sloped or bevilled, so
that when secured in its proper place it may fit very close to the under side of
the iron cross bar or bearer. The object of this arrangement is to afford an
opportunity, when required, for inspecting the tube plate and tube ends next
the furnaco without removing any part of the furnace except the iron box or
air passage, which is so made that it may be readily drawn out of the hori-
zontal cylinder or fire box when cold, the space beneath the iron cross bar or
bearer being made sufficient for a man to creep through. In the construc-
tion of the hanging bridge No. 2 (before referred to), it is preferred to have
it moulded of fire clay in such moulds or shapes as may be most conveniently
obtained; but these moulds or shapes, when put together in the combustion
'chamber and beyond the fire-brick bridge No. 1, must form a mass of fire
brick or fire clay so dovetailed or fitted together as to be self-supporting, and
closely fitting the top part and sides of the inside of the horizontal cylinder or
fire box for about two-thirds of its cross section. The middle in the highest part
of the bottom edge, which is preferred to be curved and concave, is intended
to be nearly the same distance from the bottom part of the inside of the hori-
zontal cylinder or fire box as the bottom of the fire-brick bridge No. 1. The
upper edge of the bridge No. 1 and the lower edge of the hang bridge No. 2;
may be made four or five inches thick in the thinnest part; it is also preferred
that both the back and front faces of the hanging bridge No. 2 shall be
'inclined or bevilled, (that is to say,) that the face or part nearest to the bridge
No. 1 shall be inclined or bevil'd about the same as the face nearest to the
tube plate of bridge No. 1, so that a longitudinal section through the centre
of the horizontal cylinder or fire box, and through the bridge No. 1 and the
hanging bridge No. 2, will shew the space or passage for the heated air and
flame to be nearly parallel between the top or convex edge of bridge No. 1
and the bottom or concave edge of the hanging bridge No. 2; and it is intended
that this space or passage between the two bridges shall not be of less sectional
area in any part than the sectional area of the space or opening between the
top edge of the bridge No. 1 and the inside of the top part of the horizontal
cylinder or fire box. It is also preferred that the other face of the hanging
bridge No. 2, or that part which is nearest to the tube plate, shall be inclined
for bevil'd in a contrary manner to the other face, or that nearest to bridge
No. 1, but at-about the same angle, so that the upper part may be nearer to

page_text: the tube plate than the lower part or concave edge; and it is also preferred
that the concave edge of the hanging bridge No. 2 shall not be nearer to the
tube plate than two feet (although much less space will do); and when there
is sufficent space or room between the hanging bridge No. 2 and the tubo
plate, it may be an advantage to build a lining of fire brick, as shown in the
Drawing, across the far end of the horizontal cylinder or fire box and against
the tube plate, but not nearer to the bottom tube or bottom row of tubes than
one inch; and when such a lining is admissible, it is preferred to have it about
five inches thick at the top edge and about ten inches thick at the lowest part,
which rests upon the inside of the bottom part of the horizontal cylinder or
fire box; but when the bottom tube or bottom row of tubes are very near to
the inside of the bottom of the horizontal cylinder or fire box, then the fire-
brick lining placed against the tube plate will not be of much service, and in
such a case it is preferred (provided there be sufficient room in the combustion
chamber and beyond the hanging bridge No. 2) to build a fire-brick bridge
No. 3 (not shewn in the Drawing, to which, however, we make no claim,)
which shall rest upon the inside of the bottom part of the horizontal cylinder or
fire box, the top edge of which may be level across, or curved, and convex and
concave, and shall be nearly on a level with the highest part of the concave
edge of the hanging bridge No. 2, and at such a distance from it as that the
least sectional area of the space or opening between the bridge No. 3 and the
hanging bridge No. 2 shall be at least one-half more than the sectional area
or opening between the top edge of the bridge No. 1 and the inside of the top
of the horizontal cylinder or fire box.
Having now described the nature of our said Invention, and the manner in
which it may be performed and carried into effect, we desire it to be dis-
tinctly understood that what we claim is, the combination as set forth and
described.
In witness whereof, I, the said William Watson Hewitson, have here-
unto set my hand and seal, this Second day of December, in the year
of our Lord One thousand eight hundred and fifty-six.
Witness,
S. CARPMAEL.
WILLIAM W. HEWITSON. (L.S.)

page_text: For readily *,
bar thus placing means at the disposal of these in thuge
o representing the catch or contrivance for withdrawing spport from the Grate supporting bar thus placing means
there is a suspended perforated plate a through
the ash-pit immediately bauath the fire bare and below this is an enclosed air passage by which cold air is conducted to the chamber where
which the supply of cold air passes into the chamber for the combustion chamber) such cold air in passing through the perforated plate g mets the arrant of heated air flame or other products fran
the furnace or fire bar which passes down the space between the two fire day a brick bridges and j becoming thoroughly minced therewith in the chamber and generally producing a brilliant flame which on leaving the
combustion chamber passes through the tubes or fluus m. mv. m. As the front end of the air passage e there is a grate or valve h for regulating the supply of cold air into such passage and chamber f and at the front end of the
grate for regulating the supply of air to the ash pit. When the full generating powers of the boiler is not required, which grates and deers may be closed so as to aut off
is also placed atthe trait end of the furnace er fire bow through which air may be admitted into it after being distributed through the perforated cast trav plate p.
ash po d there is a pair of doors o. e. in each of which there is a
or acclude the supply of air to the furnare at that place. A grate