Improvements in Steam Boilers and Boiler and other Furnaces.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in Steam Boilers and Boiler and other Furnaces.
I, ORLAND DORE ORVIS, of Chicago, County of Cook, State of Illinois, United
States of America, Mechanical 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 relates generally to improvements in steam boiler and other
furnaces in which a fire chamber is entirely within the confines of a solid arch
spanning a grate bar surface, and whence the products of combustion must escape
through its end, or else downward through the grate bars, before they can enter a
combustion chamber either immediately above or rearward of the fire chamber;
but more specifically to the structure shown, described and claimed in the
U.S. Patent 486,122 November 15th 1892 and British Patent No. 20,689
November 15th 1892, in which, in a downdraft furnace there is a draft passage
through which the down draft products of combustion are conducted to a combustion
chamber over the fire chamber and at a point forward of the rear end of said
combustion chamber.
The prime object of this invention is to successfully utilize to a maximum degree
an arch-like fire chamber structure of a steam boiler or other furnace as a direct
heating surface for boiler or other water, and at the same time promote the
protection of that structure from the destructive effects of the high degree of heat
to which it is necessarily subjected.
A further object is not only to utilize an arch-like fire chamber structure as a
heating surface for boiler or other water, but in such a manner that the heat units,
rising in a vertical line from the bed of burning fuel within the fire chamber, and
at their highest temperature, shall impinge against the under water heating surface
of the arch and be held in contact therewith the greatest possible time consistent
with their successful after discharge into the furnace combustion chamber for
further work, and that the upper surface of the heating chamber of the arch shall
receive the direct contact and effect of said heat units before they have ascended
substantially above the bottom of said combustion chamber, or in contact with the
crown sheets of a boiler or other surface to be heated, whereby the water heating
capacity of the surfaces of an arch are promoted to a maximum degree, while at
the same time said surfaces and other. surfaces beyond the arch are to a corresponding
degree protected from the destructive effects of furnace heat.
A further object of this invention is to substantially and materially increase the
water heating surface of a steam boiler furnace in such a manner that the entire surface
of the boiler within the furnace, and this increased heating surface, shall be subjected
to substantially all of the heat units of a furnace under the most favorable conditions
possible for vaporizing water, and this without substantially increasing the dimensions
of any portion of said furnace or boiler, or diminishing any chamber or the grate
surface thereof.
Other objects of my invention, more in detail, are the utilization of the arch or
arches enclosing the fire chamber of a down draft furnace as a direct heating
surface for boiler or other water, and as a means for promoting the circulation of
water through a boiler and through a hollow grate bar surface, and by such an
arrangement of parts that every atom of heat produced in the fire chamber of a
down draft furnace, when at its highest temperature, and temporarily confined,
shall be directed in straight and direct lines against and absorbed as fully as
possible by an extended water heating surface in close proximity to the burning
fuel, whereby water is rapidly reduced to vapor and the temperature of these
vapors raised to the utmost capacity possible by a unit of heat of any given degree,
and this without the employment of any degree of temperature therein unduly

page_text: promoting the destruction of the boiler shell, while at the same time said arch
or arches and grate-bar surface are effectively protected from destruction by
furnace heat.
A further object is not only to convert the arch or arches of a down draft
furnace into a water heating surface and to employ in connection therewith a single
or double hollow grate bar surface affording additional water surface, but to have
such a connection of these hollow grate bars with each other and with the arch or
arches that there shall be an open communication between all of these parts; that
the grate bars and arch or arches may be permanently connected and bodily placed
in or removed from a furnace, and one or more grate bars removed or inserted
conveniently, and without disturbing any other portions of the structure, whereby
the necessity of putting together the arch and grate bar surfaces within the furnace
is avoided, and time is correspondingly saved in combining my invention with an
ordinary steam boiler furnace already in use.
'
Further objects of my invention, hereinafter described and claimed, are attained
by the devices illustrated in the accompanying drawings, in which
Fig. 1, illustrates in detail a central longitudinal section of a down draft steam
boiler furnace embodying my invention:
Fig. 2, a transverse section thereof on the line 2-2, of Fig. 1:
Fig. 3, a front elevation of the same with the furnace walls removed:
Fig. 4, an enlarged rear end elevation of one of the arches:
Fig. 5, a transverse section on the line 5-5 of Fig. 6 of a down draft steam
boiler furnace, showing the embodiment of my invention in a single arch fire
chamber structure; and
Fig. 6, a central longitudinal section of the same.
Similar letters of reference indicate the same parts in the several figures of the
drawings.
A, A, indicates the side walls, and B the rear end wall of a steam boiler furnace
supporting a steam boiler C, of the ordinary construction in the usual manner and
provided with one or more furnace doors D, and ash pit doors E, of the usual
construction and arrangement, the rear end of the ash pit being closed by a bridge
wall F, the front side of which is stepped, as shown, and for the purpose
indicated:
Arranged longitudinally of the chamber thus formed between the bridge wall
and the front wall of the furnace, are arches G, G¹, which, as shown, may be set
partially into the side walls of the furnace, but if desired may be set against said
side walls, or at a point removed therefrom, and supported at each end respectively
by the front wall of the furnace and the bridge wall, but, in any event, are so
arranged relative to each other that there is a passage a at one or both sides,
extending substantially their entire length.
The forward end of these arches is open and registers with the fire chamber
door-way, and their rear end closed by a head G2 which head or end and the body
of the arch consists of an inner and outer shell providing between them a closed
water chamber b, of considerable capacity, the walls of which are preferably
constructed of steel, but may be of any other suitable material adapted for a water
tight chamber subject to furnace heat.
At the forward end of the arch is a header c, in open communication at both ends
with the base of the water chamber of the arch and having also in communication
there with grate bars d, the opposite ends of which are connected and in open
communication with the chamber of the head G2, as indicated in Fig. 1, which grate
bars d, in connection with the arch or arches G, G' constitute the fire chamber H,
of the furnace.
If desirable, for increasing the grate and water heating surface, the hollow grate
bars may be "staggered," that is to say, alternately arranged in differing planes,
and are preferably secured in connection with the header, c by screwing them into
the wall thereof and to the end G2 by means of an ordinary elbow coupling e, as
shown in Fig. 1, which mode of connection of the grate bars with the arches provides

page_text: for the construction of the fire chamber in its entirety before insertion into a furnace,
and for the convenient bodily insertion and removal of one or more grate bars from
a furnace, and also when at any time desirable.
In other words, considerable saving of valuable time is effected in combining my
invention with an ordinary steam boiler furnace, by reason of this construction
providing for joining bodily all of the parts of a fire chamber structure, and in this
condition setting them into the furnace, for any of the grate bars, though thus
fitted and permanently joined to the arch or arches before insertion into the
furnace, may be removed and inserted at any time thereafter without disturbing
the arches, and also the entire fire chamber structure be removed for any purpose
whatever.
g
In a plane below the fire chamber grate bars d, and in the ash pit of the furnace,
arranged substantially in a plane with the grate bar surface d, are a series of
pipes f, removably secured at their rear ends to a header g, by ordinary coupling h,
and at their forward ends are screwed into a header k, the header 9 being connected
with the grate bars d by means of a pipe i, and a T coupling j (see Fig. 1),
whereby the rear end of the pipes f and the header g may be suspended from the
upper grate bar surface d, but are perfectly supported by a ledge of the bridge
wall, as indicated in Fig. 1, or may be by projecting the headery into the side walls
of the furnace, or supporting it upon suitable brackets secured thereto, as headers
are commonly supported in furnaces.
The supply of water to both the arch or arches, the grate bars and the water
heating surface or pipes k, may be separate or conjoint from two sources, as for
instance, through a pipe m communicating with the boiler and with the headers c
and k, or by means of a pipe n, in communication with a water system or feed
water heater, and connected with both the header c, and header k, by the pipe or
pipes m, or, if desired, water from the boiler may be supplied to the water chamber
of the arch and the grate bars of the fire chamber from the boiler, and the cold
water be supplied to the pipes, f, in the ash pit through the pipe n.
This
latter mode is preferable because a supply of water through the pipe n, is an
additional supply for the boiler, having its temperature raised before admission
thereto, and by first passing through the pipes, the header g, and thence into
the grate bars d, and water chamber of the arch, where it is combined with the
more highly heated water in said chambers, and discharged with them into the
boiler.
A continuous circulation of water through the arch chamber and the grate bar
surface and pipe f, and a supply of said water to the boiler, is established by a
pipe o, connected with the water chamber b, of the arch, preferably in a plane
above the opening of the supply pipe m therein, and as shown, by inserting the
pipe o, into the top or crown of the arch, an ordinary elbow joint p, being used for
the purpose of this connection of the pipe o, with the water chamber d, and
providing for the convenient connection and disconnection of the arch with said
exit pipe 0. The exit or discharge pipe o, while not so shown, may be extended to
the rear end of the boiler and connected therewith either in a plane with or above
that of the orifice of the pipe m, which extension of the pipe, through the combustion
chamber of the furnace, correspondingly increases the extent of the water heating
surface therein, but it would be no departure from my invention, to provide a
pipe connection from the arch water chamber to any point of the boiler, though
obviously, a greater length of circulation of the water through the boiler, and
an increase of heating surface is provided by the end connection before described.
In Figs. 5 and 6, my invention is illustrated as embodied in a down draft furnace,
in which all of the products of combustion escape downwardly through the grate
bars, and from the rear end of the arch, over the bridge wall, to the usual furnace
combustion chamber rearward thereof, and hence rendering the space or chamber
between the arch and the boiler a dead-air space, correspondingly reducing the
water heating surface of the boiler, and this by reason of there being no passage or
passages up, through which the down draft products can ascend to said chamber,

page_text: In this connection it is proper to observe that it would be no departure from the
spirit of my invention, as set forth herein, to embody it in any updraft furnace
wherein the grate surface is spanned by an arch extending throughout its length,
and the products of combustion from the fire chamber pass directly through the
end of said arch to and over the bridge wall.
Nor would it be a departure from my invention in so far as it broadly includes
the utilization of a fire chamber arch as an extended heating chamber, to substitute
the ordinary solid grate bars for the hollow bars herein shown and described nor
to embody it in a furnace wherein is employed a baking, heating or other oven
instead of a steam boiler, for obviously the water heating capacity of the arch and
the utilization of the products of combustion in the fire chamber for heating the
water of said chamber and the protection of the arch by that water will remain the
same in all of these different structures, wherein there is the same arrangement of
arch, though obviously the heating capacity of the water chamber arch is materially
and substantially increased in a down draft furnace, when there is a direct updraft
passage at one side of and extending the length of the arch or arches thereof, by
means of which a heretofore dead-air chamber above said arch or arches is converted
into a direct draft chamber, and by this means the outer water heating surface of
the arch or arches is subjected to the heat of these products of combustion, as they
are not in the construction shown in Figure 4, and in the open rear end arch of the
'direct upward draft furnace referred to.
The present invention can be adapted to ovens by any mechanic of ordinary
skill, by substituting any suitable hot air chamber for the hot water chamber,
that is to say, the boiler shown, and this without any change in the construction
and by simply lifting out the boiler and putting in its place a chamber such as is
commonly used for ovens, that is to say, a square or other form sheet iron or brick
chamber.
The embodiment of my invention in the side draft structure of a down draft
furnace illustrated herein in Figures 1 to 4, is a very substantial improvement in
down draft furnaces, as compared with the structure shown in Figures 5 and 6, and
this not only because of the subjection of the upper end outer water heating
surface of the arch to direct draft heat, but for the additional reason that a much
more effective draft, and correspondingly rapid combustion is secured, for that, by
this exclusive end discharge in a down draft furnace, as practice demonstrates, there
to be a choking of the heat products in the passage between said end and the
combustion chamber rearward of the bridge wall; whereas, in my particular
structure, an extended updraft passage at one side of the arch receives the down
draft products as fast as they can descend through the grate bars, and as rapidly
conducts them to the combustion chamber or chambers of the furnace or boiler, as
may be and this is true whether the combustion chamber extending the length of
the arch is immediately over or in part or wholly at one side thereof, as I have
discovered since filing the joint application aforesaid.
For these reasons the invention embraced by the arrangement of the arches
shown in Figs. 1 and 2, is not to be limited specifically to a down draft furnace,
wherein there is a. draft passage through which the down draft products of
combustion are conducted to the combustion chamber directly over the fire
chamber, and at a point forward of the rear end of said combustion chamber, as
claimed therein, but includes a down draft furnace, the grate bar surface of which
is enclosed by an arch or arches so arranged as to provide a direct draft passage at
one side of and extending the length of said arch or arches, whether or not said
direct draft passage communicates with a chamber immediately over or in part or
wholly at one side of said arch or arches, and this whether or not the arch or arches
are solid or provided with a water heating chamber partly or wholly throughout
their surface.
In all down draft furnaces, prior to my invention, of my joint application, the
fire. chamber grate bars must be so far apart in order to have a sufficient
draft for their practical operation that a large amount of unconsumed coal fuel

page_text: drops through them to save which, the common practice has been to have in a
plane below the fire chamber grate bars, a supplemental grate surface with the
bars closer together than the fire chamber grate bars, for catching and sustaining
said unconsumed fuel until reduced to ashes.
There are however, several unavoidable, objectionable results due to the use of a
supplemental grate surface, among which may be mentioned the necessity of raking
down two grate surfaces for every fire chamber, the additional expense in first cost
and after repairs and renewals and the occupancy of space more valuable solely for
water heating purposes.
Furthermore, the application of these prior down draft structures to ordinary
furnaces already in use and of which there are thousands in basements and under
sidewalks and elsewhere, is impossible wherein, on account of drainage, the bottom
of the ash pit cannot be lowered, as must be, in order to provide between the fire
chamber grate surface and the supplemental grate surface, a chamber of a capacity
sufficient for the commingling and expansion of the products of combustion from
both grate surfaces to a degree necessary for the successful utilization of those
products, and as a condition precedent to their successful discharge to and over the
bridge wall, even under the most favorable conditions for a furnace draft.
At best however, the consumption of fuel on a supplemental grate surface
requires an air supply upwardly therethrough from the ash pit, which supply
unavoidably causes a draft opposing and consequently retarding a downdraft of the
products of combustion in the fire chamber to a degree practically rendering null
any advantages accruing to the saving of fuel by means of the supplemental grate
surface.
Not only does this updraft oppose the descent of the products of combustion
through the fire chamber grate surface, but so does the rising of the products of
combustion by their mutual tendency from the supplemental grate surface, and
when to these combined forces is added in any prior down draft structures, the
further requirement that a very large portion of the products of combustion must
traverse the length or a substantial portion of the intermediate chamber horizontally
before the possibility of their escape over and to the bridge wall, it is obvious, that
at best, the employment of a supplemental grate surface in these prior structures
or in any down draft structures, is a serious obstruction to the successful
operation.
Now my invention may be applied to any ordinary furnace already in use without
increasing or diminishing the depth of the ash pit or the original distance between
the bottom of the ash pit and the fire chamber grate surface, while at the same
time, the down draft of the furnace and the rapid and complete combustion of fuel
on the grate surface of the fire chamber and without any waste of fuel, is promoted
to a substantial degree as compared with any of the prior down draft structures,
and all this by reason of the fact, that there are no air currents or draft opposing
the descent of the down draft products, and that immediately they discharge down-
wardly through the grate bars they are free to escape laterally from beneath them
along the entire length of the fire chamber and in the most direct path therefrom,
and rise by their natural tendency or gravitation into an enlarged chamber in which
they are free to fully expand and be conducted thence to and over the bridge wall
without crowding or choking at any point, while at the same time, their onward
movement is accelerated by an unobstructed and perfectly free combustion chamber
draft.
In other words, by my invention, the combustion of fuel in the fire chamber of a
down draft furnace, the rapidity of its combustion, the discharge of the products of
combustion therefrom and through the entire length of the furnace and over the
surfaces therein to be heated, is promoted to a maximum degree and this without
any waste of fuel, and by devices requiring no objectionable changes in an ordinary
furnace to incorporate them, while, at the same time, as shown by the pipes k, the
chamber below the fire chamber grate surface is successfully utilized for increasing

page_text: the water heating surface of a furnace, and this without any obstruction to the draft
of the furnace or objectionable obstruction to the ash pit.
In the operation of my device, with a bed of burning fuel on both of my grate
bar surfaces, and a circulation of water from any source through the arch or arches.
and these grate bar surfaces, to any supply, it is apparent that the inner water
heating surface of the arch structure will be subject in all of the arch structures I
describe, to products of combustion rising from and confined between the surface of
the fuel and said inner water heating surface, and that said products of combustion,
after substantial absorption by this heating surface, will pass directly from the fire
chamber to the combustion chamber very little reduced in temperature, and in
down draft furnaces of this character, not reduced at all in temperature, but in the
highest degree possible, by reason of their after passage through the body of
burning fuel.
In my special structure however, and by reason of the extended updraft side
passage, the heat units are utilized with substantially better effect upon this inner
water heating surface of the arch than in any of the other structures herein shown
and described, and for the reason that the heat units, coming in contact with the arch,
ascend thereto and descend therefrom on practically direct lines, at which they best
impart their heat to a contracting surface; and furthermore, because by this
ascending and descending in the fire chamber above the burning fuel, their time of
confinement therein and their contact with the water heating surface is substantially
prolonged whereas, in an updraft furnace, and also in a down draft furnace having
exclusively an end discharge, the heat units are constantly moving in a horizontal.
direction against this inner surface.
In the meantime the products of combustion from the grate bars, after descending
therethrough upon the pipes f, raise the temperature of the water therein, thus
making said pipes a desirable auxiliary water heating surface.
As the temperature of the water is raised both in the arch water heating chamber,
the grate bars and these pipes, it rises and discharges through the pipe o, the
circulation of the water to this end being substantially promoted by means of the
header, and also by the connection of these grate bars with the water chamber b,
of the arch.
When this arch and grate bar structure is employed in connection with a steam
boiler furnace, as, for example, by the pipes m, and o, as before described, water
at quite a high temperature will be supplied to the boiler in starting the furnace,
and this is a considerable time before the heat of the furnace imparted to the crown
sheets of the boiler can possibly raise the temperature of the water therein.
In view of this operation the arch water chamber is not only an extended water
heating surface auxiliary to the boiler when the furnace is in full operation, but is
an important factor in the initial heating of the boiler water, and also in raising
the temperature of the boiler water quickly when already heated.
The capacity for heating boiler water and the extent of the heating surface of
the arch chamber may be appreciated when it is borne in mind that by the use of
these arches in the usual fire chamber of a steam boiler, the heating surfaces are
increased two hundred and fifty square feet, and that as five square feet of these
highly heated water surfaces are equal to one horse power, the addition of 250 square
feet of heating surfaces adds fully 50 horse power to the boiler.
The importance of my invention in connection with a steam boiler furnace is not
confined to the fact of the extended water heating surface it provides, but more
largely to the manner of utilizing that surface so as to subject it to heat of the
degree, and in the manner already described.
In conclusion it is proper to observe, that an important advantage is gained by
having an updraft passage along the side of the arches, in that the length of the
grate surface may be extended without limit and a correspondingly larger area of
grate surface be operated without any reduction or retardation of the draft in any
portion of the furnace, and as cannot be when an exclusively end up draft passage

page_text: is employed, because, even with a length of great surface very short as compared
to the usual length of mine, to say nothing of the extension permissible by my side
updraft passage, the objectionable crowding and choking of the products of com-
bustion and retarding of draft, before stated, is correspondingly increased as the
length of the grate surface is increased, and said products are compelled to travel
a greater distance before reaching the updraft passage.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
1 The combination in a furnace, of grate bars, a fire chamber, an arch enclosing
said fire chamber and provided with an internal water heating chamber, and a draft
passage beyond the side of and extending lengthwise of said arch, substantially as
set forth.
2: In a down draft furnace, the combination with the grate bars, of an arch
spanning the surface of the same, enclosing the fire chamber and provided with a
water heating chamber between its inner and outer surfaces and substantially
throughout the extent of said surfaces, and an updraft passage at the side of and
lengthwise of the arch, substantially as set forth.
.
3: In a down draft furnace, the combination with the grate bars, of an arch or
arches enclosing the same, and arranged to provide a direct updraft passage at one
side of and extending substantially the length of said arch or arches, substantially
as set forth.
4: In a down draft furnace, the combination with an arch or arches spanning
the grate bar surface and enclosing the fire chamber, which said arches are so
arranged as to provide a direct draft passage at one side of and extending substan-
tially the length of said arch or arches, and a water chamber enclosed by the
opposing surfaces and extending substantially throughout said arch or arches,
substantially as set forth.
5: In a steam boiler furnace, the combination with the grate bars, of a closed
arch or arches spanning the surface of the same and enclosing the fire chamber, a
water chamber between the inner and outer surface of said arch or arches and pipe
connections between said chamber and the boiler whereby a continuous circulation
of water from and through the boiler and said arch or arches and the grate bars, is
maintained, substantially as and for the purpose described.
6: In a furnace, the combination with hollow grate bars, of a closed arch
spanning the surface of the same, and provided throughout its length with an
internal water chamber connected with said grate bar surface, and also with a
suitable source and supply whereby a continuous circulation of water is maintained
through the hollow grate bars and arch, substantially as and for the purpose
described.
7: In a down draft steam boiler furnace, the combination of hollow grate bars,
an arch or arches spanning the same, enclosing the fire chamber and arranged to
provide a direct draft passage at one side of and extending the length of said arch
or arches, a supply and discharge pipe connection between said arch or arches and
the boiler, and water connection between said arch or arches and the grate bar
surface or surfaces thereof whereby a continuous circulation of water in the boiler
and in said arch or arches and grate bars is maintained, and the initial and
subsequent heating of the boiler water is promoted, substantially as set forth.
Dated this 21st day of December 180
ORLAND DORE ORVIS.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.