IMPROVEMENTS IN BOILERS FOR LAUNCHES AND OTHER PURPOSES
Year: 1884

page_text: TOOK
I FREDERICK JOHN BURRELL of Saint Nicholas Works, Thetford in the
County of Norfolk Engineer do hereby declare the nature of my Invention for
"IMPROVEMENTS IN BOILERS FOR LAUNCHES AND OTHER PURPOSES" to be as
follows:-
This Invention has for its object improvements in boilers for launches and other
purposes. It has a nearly cylindrical shell, a fire box with circular top and return
tubes. The shell of the boiler instead of being carried round under the furnace is
brought down and rivetted to a solid foundation ring which ties it together. The
firebox is fixed to this ring as in a locomotive boiler and the fire bars are just
above the foundation ring. The combustion chamber which is lined with firebrick
is attached outside the boiler at the back and communicates with the firebox by
some large tubes which pass through the water space. Immediately above and on
each side of the firebox are horizontal tubes connecting the combustion chamber
with the smokebox. A door is fitted to the combustion chamber to give access to
the tubes. By this arrangement the tubes are immediately accessible at both ends
without disturbing the boiler a feature of great importance. The centre of gravity
of boiler is kept very low and a very large amount of efficient heating surface is
obtained in a small space. This boiler is specially adapted for consuming its own
smoke, a large grate area is secured and scarcely any dead water is carried. Thero
are no stays in the firebox in contact with the flame and owing to the large tubes
used to connect the firebox to the combustion chamber, the tube plate of the box
is subject to an almost uniform action of the flames on its entire surface, thus
avoiding the wear and tear usual on one individual part or where there are two
thicknesses of plate.
There are no stays required in the firebox or in the cylindrical shell owing to
their being rigidly connected at the bottom by the foundation ring. Longitudinal
stays tie the back and front boiler plates as is usual in marine and other boilers.
In addition to the above features, for cheapness of manufacture, strength and
lightness it has great advantages over other boilers and is far more easily repaired.
It takes up inuch less room on the line of keel than the locomotive type which
for small launches is now generally adopted. It combines the advantages of both
the marine return tube and locomotive type boiler without the disadvantages of
either.

page_text: I, FREDERICK JOHN BURRELL of Saint Nicholas Works, Thetford, in the County
of Norfolk Engineer do hereby declare the nature of my Invention for "IMPROVE-
MENTS IN BOILERS FOR LAUNCHES AND OTHER PURPOSES" and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement:—
This Invention has for its object improvements in boilers for launches and other
purposes. It has a nearly cylindrical shell or firebox with circular top and return
tubes. The shell of the boiler instead of being carried round under the furnace is
brought down and rivetted to a solid foundation ring which ties it together. The
firebox is fixed to this ring as in a locomotive boiler and the fire bars are just
above the foundation ring.
The combustion chamber which is lined with firebrick is attached outside the
boiler at the back and communicates with the firebox by some large tubes which
pass through the water space. Immediately above and on each side of the fire box
are horizontal tubes connecting the combustion chamber with the smoke box. A
door is fitted to the combustion chamber to give access to the tubes. By this
arrangement the tubes are immediately accessible at both ends without disturbing
the boiler a feature of great importance. The centre of gravity of boiler is kept
very low and a very large amount of efficient heating surface is obtained in a small
space. This boiler is specially adapted for consuming its own smoke, a large grate
area is secured and scarcely any dead water is carried. There are no stays in the
fire box in contact with the flame and owing to the large tubes used to connect
the fire box to the combustion chamber, the tube plate of the box is subject to an
almost uniform action of the flames on its entire surface, thus avoiding the wear
and tear usual on one individual part or where there are two thicknesses of plate.
There are no stays required in the firo box or in the cylindrical shell owing to
their being rigidly connected at the bottom by the foundation ring. Longitudinal
stays tie the back and front boiler plates together as is usual in marine and other
boilers. In addition to the above features, for cheapness of manufacture, strength
and lightness it has great advantages over other boilers and is far more easily
repaired. It takes up much less room on the line of keel than the locomotive
typo which for small launches is now generally adopted. It combines the
advantages of both the marine return tube and loco: type boilers without the
disadvantages of either.
In order that my said Invention may be most fully understood and readily
carried into effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is on and view helf in section of a boiler constructed according to my
Invention.
Figure 2 is a side elevation in section of the same.
The shell A is rivetted to the solid foundation ring B by
together at the bottom. The crown and side plate C³ of the
rivetted to the same ring as in the locomotive type of boiler.
which it is tied
firebox C is also
The foundation
Invention.
Figure 2 is a side elevation in section of the same.
The shell A is rivetted to the solid foundation ring B by which it is tied
together at the bottom. The crown and side plate C of the firebox C is also
rivetted to the same ring as in the locomotive type of boiler. The foundation
ring is carried up at the front end and forms also a ring for the fire door D.
The spaco left open below the fire door being filled by a dead plate E which 4
carries the centre firebars. By this means the front plate of the inside firebox is
thoroughly stayed and the weight of that part of the boiler reduced. The large
tubes F convey the products of combustion from the firebox to the combustion

page_text: chamber G which is lined with firo brick and fitted with a door G³ for access to
the tubes and for cleaning out. This combustion chamber is fitted to the back
end of the boiler and conducts the heated gases from the firebox through the return
tubes E to the smoke box on the front of the boiler. The firebox C boing
circular crowned gives great strength, facilitates consumption of smoke and
dispenses with stays in contact with the flame as in the "Loco" type of boiler.
The tube plate K is stayed to the back shell plate by the large tubes F which pass
through the water space and are screwed into both plates, thus distributing the
flames over a large area and avoiding the injurious effect of contracting the opening
leading to the combustion chamber subject to the action of intense heat-such
connections being made in some boilers by lap joints or welds. The foundation
ring B is slanted towards the combustion chamber end thus giving increased area
for draught at the front end without increasing the height of the boiler and giving
greater depth of tube plate. By connecting the ash pit L with the combustion
chamber G by means of some small tubes M, warm air is admitted to the
combustion chamber to assist in consuming the smoke. N is a steam dome or
receiver, preferably made in the form shown in order to reduce weight and assist
in keeping the centre of gravity of the boiler low. If desirable it may be made to
extend from back to front of the boiler or made circular in the usual way. The
back and front shell plates are stayed by the stays O between angle irons Privetted
to the shell plates. By this construction of boiler the tubes are immediately
accessible at both ends when necessary for examination or repairs without
disturbing the boiler or any of its mountings, it enables the marine return tube
principle to be applied to small boilers for launches where from costliness of
imanufacture and inaccessibility of parts it would otherwise be impracticable.
There is a good length of tube and compared with the locomotive type of boiler it
has great advantages in saving length on the line of keel, a larger grate area,
greater economy of fuel and more perfect combustion of the gases, prevention of
smoke, lower temperature of the smoke box and funnel owing to all the available
heat being abstracted before it reaches the funnel, greater facilities for repairs and
an absence of all short stays in the fire box in contact with the flames.
Having thus particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what 1
claim is:-
A boiler with shell A, foundation ring B, plate C², enclosing a fire box which
communicates with a combustion chamber, and return tubes H substantially as
described.