IMPROVEMENTS IN GENERATING HEAT AND STEAM IN MARINE BOILERS
Year: 1876

page_text: LETTERS PATENT to Frederick Haward, of Gracechurch Street, in the City of
London, for the Invention of "IMPROVEMENTS IN GENERATING HEAT AND
STEAM IN MARINE BOILERS."
Scaled the 24th November 1876, and dated the 31st May 1876.
PROVISIONAL SPECIFICATION left by the said Frederick Haward at the
Office of the Commissioners of Patents on the 31st May 1876.
FREDERICK HAWARD, of Gracechurch Street, in the City of London.
MENTS IN GENERATING HEAT AND STEAM IN MARINE BOILERS."
"IMPROVE-
This Invention relates to certain improvements in the means of generating heat
and steam in marine boilers, effected by special arrangements in regard to the
furnace and the combustion of fuel, the passage of the gases so generated and their
admixture with atmospheric air, their ultimate consumption in a combustion
chamber, and the application of heat thereby generated to the upper part of the
boiler, so that the water may be more readily converted into steam than if the heat
were applied more directly to the lower portion of the boiler.
The advantages of these arrangements are very great, because by the complete
utilization of the fuel by a perfect combustion of all its elements the greatest
amount of heat is generated from the fuel, and also because such heat is applied in
the most economical method, the smoke being almost totally prevented.
In marine boilers it has hitherto been difficult to effect the suitable supply of air
to the furnace for reasons well understood, and my Invention primarily relates to
this subject.
With regard to existing boilers where the grate is within the boiler, I propose
to apply the grate bars in a lower position than heretofore, whereby I obtain a
deeper layer of fuel, which enables me to adopt an improved system of fire bars by
making the grate in, say, three divisions from front to back, so that I can remove
any one series of bars, comprising three, four, or more bars, without disturbing the
other portion of the grate. To accomplish this I dispense altogether with the
ordinary dead plate which supports the grate, and I substitute independent vertical
supports which can be removed alternately at pleasure, and thus I can at any time
introduce into the incandescent fuel a new series of bars above the others (say, for
example, the central series), by which means I support the fuel while I remove the
under bars and then allow the new series to fall into their place. 1 forn a series
of channels or air passages in the front masonry of the furnace and in the furnace
[Price 6d.]

page_text: door; these are regulated by slides, so that I can regulate the supply of air above
the fire, the draught rushing also through the ash-pit and fire bars to aid the
combustion.
We thus reach the point of primary combustion of fuel and generation of gases,
which are then conducted to a combustion chamber extending to the rear of the
boiler behind the tubes. Now, at the back of the boiler I make an opening or
manhole through the walls of the boiler so as to come directly under the combustion
chamber, and through this opening a current of air is conducted and made to pass
under and over a divisional plate or diaphragm, from which it acquires heat from
the furnaco and then immediately mixes with the gases in the combustion chamber.
The air in entering the combustion chamber passes through a wall formed of iron
or bricks, or a combination thereof, perforated with a number of small holes or
slots, and a portion of this wall may be moveable, and this part of the Invention
may be applied in all the examples mentioned herein.
For regulating the draught in each combustion chamber separately I apply a
separate uptake having a damper therein loading to the common funnel. The
result is that the most perfect consumption of the gaseous clements takes place
with the special advantage that the greatest of such heat as is generated is imme-
diately drawn through the upper series of tubes, so that a very rapid evaporation
of steam occurs in comparison with what would be obtained by such special appli-
cation of heat in the lower series of tubes.
It will be observed that whatever the nature of the fuel used the products
resulting are conveyed to the chamber where they are subjected to ultimate
destructive decomposition by the agency of atmospheric air, the carbonic oxide
being rendered capable of giving out the greatest possible degree of caloric.
In other examples, where a new construction of boiler is desired, the furnace
should be brought forward,either partly or wholly inside or entirely in front of the
boiler, that is to say, in the present stokehole in the front of the boiler. By these
menus I obtain a much greater depth of furnace bars, and consequently a deep layer
of fuel and a more complete generation of heat-giving gases, which are then con-
veyed along the lower part of the boiler leaving the incandescent fuel clear of the
boiler, and thus the Invention is rendered more efficacious because we have the
greatest amount of heat generated and applied as before stated to the upper surface
of the water.
The opening or space above the bars in front of the furnace across its entire
breadth may be closed by doors or covers having slots for admission of air, the
opening of which can easily be regulated according to the amount of air required.
Also slots for admission of air are to be made in the fixed front of the furnace, or
the air for the ignition of the gas may be led through the furnace tube in which
the gases are generated to the combustion chamber, or the air may be first heated
in a separate furnace previous to meeting the gases.
I also apply the furnace wholly or partly under a cylindrical boiler (not having
an inside furnace) but having an internal combustion chamber similar to a loco-
motive boiler, or to a cylindrical boiler not having an inside furnace, but having a
combustion chamber built up at the rear of the tubes, in which latter case the brick
wall so built up will serve as a partition wall for the combustion chambers of two
boilers placed end to end. Or instead of the wall or division there may be a com-
plete space between the rear ends of the boilers serving as a common combustion
chamber for both.
These arrangements may be also applied to water tube boilers. In all these
examples the air for igniting the gases and for passage under the grate may be
forced or drawn by artificial means.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Frederick Haward in the Great Seal Patent Office on the 28th November
1876.
FREDERICK HAWARD, of Gracechurch Street, in the City of London. "IMPROVE-
MENTS IN GENERATING HEAT AND STEAM IN MARINE BOILERS."
My Invention relates to certain improvements in the means of generating hent
and steam in marine boilers, effected by special arrangements in regard to certain
parts of the boiler and furnace, and to the combustion of fuel, the result being that
the combustible gases arising from the fuel are inet at the back of the furnace and
the lower part of the combustion chamber by currents of heated air, which cause
their ignition and effect a complete combustion of the fuel and evolution of heat.
The advantages of these arrangements are very great, because by the perfect
utilization of the fuel thus obtained by the combustion of all its elements the
greatest possible amount of heat is generated, and is applied by my Invention in a
more economical method than has hitherto been done, because the maximum of
such heat exists in the upper part of the combustion chamber, and is consequently
made to act on the uppermost series of tubes within the boiler, thus causing a
much more rapid evaporation or generation of steam than would otherwise occur.
In order to fully explain my Invention I refer to the accompanying Drawings,
of which Figure 1. represents a longitudinal vertical section of a marine boiler with
inside furnace and combustion chamber. The air for the ignition of the gases
which are produced in the furnace a is forced into pipes or passages in the front
uptake, from thence through the tubes g, which are in the water space, thence into
pipe in combustion chamber, and finally into the box B, from whence the heated
air escapes through small openings.
In Figures 2 and 3 the air is heated in tubes and passages i in the lower part of
combustion chamber.
Figure 4 shews a boiler with no inside furnace. Here the gas producer is placed
below the boiler. The fuel is placed in the furnace a on a grate; this furnace I
term the gas producer; c is the ash-pit. It will be observed that I place the fire
grate in such position that the distance between the furnace top and the fire grate
bars is much greater than usual in marine boilers, which affords more space for
generating the combustible gases, and hot air may be blown under the grate.
In Figure 1 the fire door d is shewn hanging downwards when shut, so that it
opens inwards.
e represents fire bricks placed under the furnace top to prevent the
gases from striking those parts when so protected. One or more boxes or chanibers
Bat the back of the producer or lower part of combustion chamber H serve to
collect the heated air for the ignition of the combustible gases, and these boxes are
provided with small openings through which the hot air for the ignition of the
gases can escape. The air is heated by the hot gases in the funnel and uptake by
the water or steam in the boiler; it may be heated in the combustion chamber or
by the heat therefrom, or in a furnace or producer, or in the walls of the same.
For example, in Figure 1 the air is heated first in the front uptake f; from thence
it is led by the pipe g through the water space of the boiler, thence to the com-
bustion chamber H, and lastly it escapes through the box B, which is at the back
of the furnace or producer.
In Figures 2 and 3 the air, before entering the box B, is driven through a series
of tubes (as before referred to) as the back of producer and lower part of com-
bustion chamber. Certain parts of these pipes or of the passages for heating the
air have openings in them for the escape of heated air. The air may be also forced
by artificial means into such pipes or passages, or may be drawn through the same,
suitable valves or cocks being applied for regulating the supply of air.
For the conveyance of air I use pipes or passages formed of metal or fire bricks,
or of metal protected by fire bricks or fire clay. The gas producer may be placed
entirely or partly in front of the boiler.
Having now described the nature and object of my said Invention and the

page_text: manner in which the same is to be performed, I would remark that I lay no clain
to the mere admixture of heated air with the gaseous and other products of the
fuel from the furnace of marine steam boilers, but what I claim and desire to be
secured to me by the herein in part recited Letters Patent are, the peculiar construc-
tion of the furnace, the placing of the gas producer below boilers with no inside
furnace, the heating of the air for the ignition of the combustible gases in the
funnel and front uptake by the water and steam in the boiler, the combustion
chamber, or by the heat thereof in the producer or in the walls of the same, or in
a separate furnace; the construction of the air passages of metal or of fire bricks,
or a combination of both; the air boxes and perforated pipes in connection there-
with, the forcing or drawing of the air through the pipes or passages, all as
substantially described and shewn in the accompanying Drawings.
In witness whereof, I, the said Frederick Haward, have hereunto set my hand
and seal, this Twenty-fifth day of November, in the year of our Lord One
thousand eight hundred and seventy-six.
Witness,
A. C. M. PRINCE,
Office for Patents,
9, Adam Street,
Adelphi,
'
F. HAWARD. (L.S.)