An Improvement in Locomotive Engines for Heating the Air Supplied to the Firebox.
Year: 1899

page_text: Date of Application, 18th May, 1899
Complete Specification Left, 16th Feb., 1900-Accepted, 14th Apr., 1900
An Improvement in Locomotive Engines for Heating the Air
Supplied to the Firebox.
I, HENRY HUINGS HUFF, of No. 343, Norfolk Street, Dorchester, in the City of
Boston, County of Suffolk, and State of Massachusetts, United States of America,
Locomotive Engineer, do hereby declare the nature of my invention to be as
follows:-
This invention has for its object to utilize the heat that is radiated from the
smoke-arch and from other exposed heated surfaces of a locomotive engine, in
heating the air that is supplied to the fire-box to maintain combustion, so that the
smoke may be more perfectly consumed. The invention consists in the improve-
ments which are hereinafter described.
The invention may be embodied in a structure comprising the usual smoke-
arch, boiler, and fire-box of a locomotive engine. Surrounding the smoke-arch.
either wholly or partially is an air-chamber, preferably of cylindrical form, having
at its front end a series of orifices that are open to the atmosphere and con-
stitute a front air-inlet. The air-chamber is preferably internally subdivided to
form a sinuous passage for air entering the said front inlet, and this subdivision
may be accomplished by means of an annular partition extending from the front
end of the chamber partly to the rear end, and another annular partition extending
from the rear end partly to the front end, said partitions causing the air to pass
through the chamber in a sinuous course. The rear end of the air-chamber is also
provided with a series of orifices which collectively constitute a rear air-inlet, said
front and rear air-inlets being opened alternately, as hereinafter explained.
A sheath or jacket wholly or partially surrounds the boiler, preferably enclosing
also the top and side surfaces of the fire-box, the said jacket being separated from
the external surfaces of the boiler and fire-box by a narrow space which con-
stitutes a conduit communicating at one end with the air-chamber and at the
other end with a flue or passage which enters the forward end of the ash-pan
under the fire-box. The sheath or jacket is preferably constructed to prevent the
radiation of heat from it, and to this end it may have a lining of asbestos or other
non-conducting material.
The ash-pan is externally closed: that is to say, it has no openings to receive
external air excepting through the flue or passage, so that all the air drawn
into the ash-pan and fire-box by the exhaust has to pass through the air-chamber
and jacket, so that when it reaches the ash-pan and fire-box it is heated to a
considerable extent by the heat radiated from the surfaces of the smoke-arch
and boiler over which it passes. The ash-pan is internally subdivided, so that the
air which enters its forward end through the flue or passage is distributed and
delivered uniformly to all parts of the grate. This result may be accomplished
by means of two longitudinal partitions extending from the forward end of
the ash-pan partly to the rear end. and a transverse partition extending across the
space between the longitudinal partitions and at the rear end thereof. The longi-

page_text: tudinal and transverse partitions form an air-receiving pocket extending from the
front end of the grate partly to its rear end, and not extending entirely across
the ash-pan, narrow spaces or conduits being formed between the sides of the
ash-pan and the longitudinal partitions. These conduits extend to a chamber
under the rear end of the grate; and conduct a part of the air that is delivered
by the flue or passage to the said chamber. By this construction, the air entering
the fire-box is prevented from passing in a greater volume through the forward
end of the grate than through the rear end, the narrow spaces or conduits
conducting sufficient air to the rear end of the grate to properly supply the
rear portion of the fire-box. The longitudinal partitions do not extend up to the
under surface of the grate, but are offset, so that they do not obstruct the
admission of air to all portions of the under surface of the grate forward of the
transverse partition.
A segmental register is arranged to close and open the openings constituting the
forward air-inlet, and a similar register is arranged to close and open the
openings constituting the rear air-inlet. In stormy weather, it is desirable to
close the openings of the forward air-inlet, to prevent the admission of rain and
snow, and at such times the air is taken in through the rear inlet; but when
the front inlet is open, it is of course essential that the rear inlet be closed.
Means are therefore provided for simultaneously moving the two registers, and said
registers and the air-openings are so arranged that simultaneous movement of
the two registers in one direction will close the front inlet and open the rear
inlet, or vice versa. To this end, a shaft is provided, journalled in bearings affixed
to the exterior of the air chamber and having gears meshing with segmental racks
affixed to the registers. The shaft may extend to the cab of the locomotive,
so that it may be operated from within the cab.
The air-chamber is preferably provided with a branch which encloses the
smoke stack and is provided near its upper end with air-inlets. The said branch
enables the heat radiated from the smoke-stack to be utilized in heating the
air supplied to the fire-box, as will be readily seen.
In addition to the advantage of providing the fire-box with heated air, thus
greatly facilitating combustion and consuming smoke, the escape of sparks, live
coals, and cinders from the ash-pan is entirely prevented, thus greatly reducing
the liability of setting fires along the track.
If desired, a portion of the air passing through the passage may be admitted
to the fire box above the usual fire-brick arch therein. For this purpose, orifices
may be made in the front water-leg of the boiler, constituting the front wall
of the fire-box.
Dated L 1
1300
An Improvement in Locomotive Engines for Heating the Air
Supplied to the Fire Box.
I, HENRY HUINGS HUFF, of No. 343, Norfolk Street, Dorchester, in the City of
Boston, County of Suffolk, and State of Massachusetts, United States of America,
Locomotive Engineer, do hereby declare the nature of this invention 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 to utilize the heat that is radiated from the

page_text: smoke-arch and from other exposed heated surfaces of a locomotive engine, in
heating the air that is supplied to the fire-box to maintain combustion, so that
the smoke may be more perfectly consumed. The invention consists in the im-
provements which I will now proceed to describe and claim.
Of the accompanying drawings, forming a part of this specification:-
Figure 1 represents a sectional elevation, showing my invention applied to a
locomotive engine.
Figure 2 represents a top plan view, showing the smoke-arch, boiler, and
fire-box.
Figure 3 is a view similar to Figure 2, showing the portions constituting my
improvement, in section.
Figure 4 represents a section on line 4 of Figure 1.
Figure 5 represents a section on line 5-5 of Figure 1, looking toward the left.
Figure represents a section on line 6-G of Figure 1, looking toward the
right.
Figure 7 represents a front elevation of the engine.
Figure 8 represents a section on line 8-8 of Figure 1.
Figure 9 represents a section on line 9-9 of Figure 1.
The same letters of reference indicate the same parts in all the figures.
In the drawings.-
a represents the smoke-arch, 6 the boiler, and the fire-box of a locomotive
engine, the same being of any suitable form and construction. Surrounding the
smoke-arch, either wholly or partially, is an air-chamber d, preferably of cylin-
drical form, having at its front end a series of orifices that are open to the
atmosphere and constitute a front air-inlet. The chamber d is preferably inter-
nally subdivided to form a sinuous passage for air entering the said front inlet,
and is here shown as thus subdivided by means of an annular partition extend-
ing from the front end of the chamber partly to the rear end, and another annular
partition extending from the rear end partly to the front end, said partitions
causing the air to pass through the chamber in a sinuous course, indicated by the
arrows in Figure 1. The rear end of the chamber d is also provided with a series
of orifices d, which collectively constitute a rear air-inlet, said front and rear air-
inlets being opened alternately, as hereinafter explained.
e represents a sheath or jacket, which wholly or partially surrounds the boiler b,
and which preferably encloses the top and side surfaces of the fire-box, the said
jacket being separated from the external surfaces of the boiler and fire-box
by a narrow space which constitutes a conduit communicating at one end with
the air-chamber d and at the other end with a flue or passage f which enters the
forward end of the ash-pan g, under the fire-box. The sheath e is preferably con-
structed to prevent the radiation of heat from it, and to this end it may have
a lining e of asbestos or other non-conducting material.
The ash-pan g is externally closed; that is to say, it has no openings to receive
external air excepting through the passage f: so that all the air drawn into
the ash-pan and fire-box by the exhaust has to pass through the chamber d and
jacket e, so that when it reaches the ash-pan and fire-box it is heated to a
considerable extent by the heat radiated from the surfaces of the smoke-arch
and boiler over which it passes. The ash-pan is internally subdivided. so that
the air which enters its forward end through the passage f is distributed and
delivered uniformly to all parts of the grate. This result is accomplished, in the
embodiment of my invention here shown, by means of two longitudinal par-
titions ii extending from the forward end of the ash-pan partly to the rear end,
and a transverse partition extending across the space between the
partitions ii and at the rear end thereof. The partitions ii and
form an air-receiving pocket extending from the front end of the grate partly
to its rear end, and not extending entirely across the ash-pan. narrow spaces or
conduits being formed between the sides of the ash-pan and the partitions i i.
These conduits extend to a chamber under the rear end of the grate, and con-

page_text: duct a part of the air that is delivered by the passage f to the said chamber 23. By
this construction I prevent the air entering the fire-box from passing in a greater
volume through the forward end of the grate than through the rear end, the
conduits conducting sufficient air to the rear end of the grate to properly
supply the rear portion of the fire-box. The partitions i i do not extend up to the
under surface of the grate, but are offset, as shown at 4 (Figures 5 and 6),
so that they do not obstruct the admission of air to all portions of the under
surface of the grate forward of the partition .
j represents a segmental register arranged to close and open the openings d¹
_constituting the forward air-inlet, and represents a similar register arranged to
close and open the openings constituting the rear air-inlet. In stormy weather,
it is desirable to close the openings d¹ to prevent the admission of rain and snow,
and at such times the air is taken in through the rear inlet; but when the front
inlet is open, it is of course essential that the rear inlet be closed. I have there-
fore provided means for simultaneously moving the two registers j j¹, and have
arranged said registers and the air-openings so that simultaneous movement of
the two registers in one direction will close the front inlet and open the
rear, inlet, or vice versa. To this end, I show a shaft k journalled in bearings k¹ k¹
affixed to the exterior of the chamber d, and provided with gears 2 meshing
with segmental racks ³ ³ affixed to the registers. The shaft may extend to the
cab of the locomotive, so that it may be operated from within the cab. Obviously,
when the front inlet only is open, a greater amount of air enters the chamber
than when the rear inlet is open.
I prefer to provide the chamber
with a branch 6, which encloses the smoke-
stacks and is provided near its upper end with air-inlets d. The said branch
enables the heat radiated from the smoke-stack to be utilized in heating the
air supplied to the fire-box, as will be readily seen.
In addition to the advantage of providing the fire-box with heated air, thus
greatly facilitating combustion and consuming smoke, I entirely prevent the
escape of sparks, live coals, and cinders from the ash-pan, thus greatly reducing
the liability of setting fires along the track.
If desired, a portion of the air passing through the passage f may be admitted to
the fire-box above the usual fire-brick arch therein. For this purpose, orifices o o
(see dotted lines, Figure 5) may be made in the front water-leg of the boiler, con-
stituting the front wall of the fire-box.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. A locomotive engine having an air-chamber exterior to the smoke-arch and
adapted to be heated thereby, said chamber being provided with means for
preventing the direct passage of air therethrough, an air-conduucting sheath
or jacket surrounding the boiler and connected at one end with the air-chamber
and at the other end with the fire-box, whereby heated air from the said chamber
is conducted in a thin stratum along the heated external surface of the boiler,
and delivered, additionally heated, to the fire-box, and means for varying the
admission of air to the said chamber.
2. A locomotive engine having an air-chamber exterior to the smoke-arch,
means for connecting said chamber with the fire-box, air-inlets at the front and
rear ends of said chamber, and registers whereby either of said inlets may be
closed.
3. A locomotive engine having an air-chamber exterior to the smoke-arch.
means for connecting said chamber with the fire-box, air-inlets at the front and
rear ends of said chamber, registers adapted to close said inlets, and means
for simultaneously operating the registers, the said inlets and registers being
arranged so that when one register is opened the other is closed.
4. A locomotive engine having an air-chamber surrounding the smoke-arch

page_text: and provided with internal horizontal partitions to form a sinuous passage, said
passage having an air-inlet at its front end, and an air-conduit surrounding the
boiler and extending from the other end of said passage to the fire-box.
5. A locomotive engine having an externally closed ash-pan, means for heating
air and conducting it to said inlet, and the longitudinal partitions ii extending
from the forward end of the ash-pan partly to the rear end, and a transverse
partition extending across the space between the partitions ii at the rear end
thereof, whereby the space within the ash-pan is divided into side conduits 2
communicating with a chamber at the rear of the partition i, for uniformly
supplying air to all parts of the grate.
Dated this 15th day of February 1900