Improvements in Economizers for Natural, Forced, or Induced Draught for Furnaces.
Year: 1898

page_text: Date of Application, 6th Dec., 1898-Accepted, 4th Mar., 1899
COMPLETE SPECIFICATION.
Improvements in Economizers for Natural, Forced, or Induced
Draught for Furnaces.
I, JOILN BROADFOOT HOUSTON, Georgia Street, Vancouver, British Columbia,
Canada, Marine Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
My invention relates to improvements in economizers for heating the air supply
or draught for furnaces.
The objects of my invention are, first: to utilize the escaping gases from the
furnace for heating the air supply before it comes in contact with the furnace.
This is accomplished by arranging nests of air tubes horizontally in the uptake
and passing the incoming air draught through the upper nests to a central chamber
and back through lower nests of pipes to the outer jacket, whence it goes directly
to the furnace. The heated gases pass around the tubes composing the suspended
nests of air pipes, and by this means a maximum heated surface is presented to
the incoming flow of air; and my second object is to so arrange the nests of air
tubes in the uptake that they may be easily removed and replaced, in case of
breakage, or in any other event, and at the same time utilizing all of the heating
surface in the uptake for preparing the incoming air for the furnace, to obtain
the most economical results.
I attain these objects by the mechanism illustrated in the accompanying
drawing, in which:
Fig. 1 is a front elevation of an uptake with a section thereof removed, showing
the position and arrangement of my invention.
Fig. 2 is a vertical section of the same, on the line C C and viewed in the
direction of the arrow.
Fig. 3 is a detailed plan of one of the upper nests of tubes, sectioned on the
line a a, and
Fig. 4 is a similar detailed section of one of the lower nests at the line b b.
Similar letters and numerals designate corresponding parts throughout the
several views.
The enlarged portion of the uptake A is provided with a jacket 10. Around
the top of this jacket 10 and forming a closure between the uptake A and the said
jacket is an annular collar 11. The jacket is carried downward to proximity with
the furnace doors, and the air space connected directly with the furnace.
As better shown in Fig. 2 the air is introduced into the jacket 10 by a duct 12;
and for better and immediate distribution of the air around the uptake a pipe 13
is passed through the same. This not only facilitates the flow of air round the
uptake, but the pipe 13 is also utilized as a heating surface to the incoming air,
by reason of the said pipe being directly in the flow of heated gas. Suspended
horizontally on either side and within the uptake, immediately above the boiler
flues, are nests of air tubes 14; and placed directly above these tubes are like
nests of air tubes 15. Centrally located between the oppositely placed nests of

page_text: air tubes is a vertical air chamber 16. The nests of air tubes on each side of the
uptake are secured together by vertical plates 17. These plates are perforated,
and the tubes snugly fit the apertures, and project slightly beyond the outer
surfaces of the plates; but the tubes are so.arranged that they may be drawn from
the openings in the plates for a reason to appear presently.
At the outer opposite ends of the tubes, the upper nests are divided off from the
lower ones by horizontal plates 18, which form partitions, so that as the cold air
passes downwards it will be.conducted inwards through the upper nests of tubes 15
to the inner chamber 16, from where it will return back to the jacket 10; and
will thus be heated in proportion to the velocity it is travelling, and the condition
of the fires in the furnace.
The central chamber 16 is provided with covers or man-holes 19, at the top and
bottom. This allows .convenient access to the inner ends of the nests of tubes,
for repairing or for removing any of the parts.
When it is desired to come at the nests of air pipes the plates 20 on each side
.of the jacket. are removed; and the central chamber 16 may be entered through
the lower man-hole, or through an opening in the uptake.above the jacket.
By reason of all the outer walls of the uptake, and the surfaces exposed to the
heated gases from the furnace, having their opposite surfaces exposed to the cold
air, danger of any of the parts being burnt or damaged by heat is minimized
wery much, as the flow of cool air will keep the temperature of the metals down;
and a further advantage is the beneficial and economical effect of exposing all of
the heated parts enclosed by the jacket to the incoming flow of air, this being one
of the essential features requisite.
It is obvious from the arrangement of the nests of tubes that the draught may
be natural, forced or induced, as the air will first radiate from the pipes 12 and 13
and pass to the opposite outer ends of the pipes 15, through which it will be
introduced to the chamber 16 and through the lower pipes 14 to the furnace,
without fans for forcing or inducing, this flow being caused by the draught of
⚫the furnace.
.
It is evident that although the air tubes will give better results by being
arranged in nests on opposite sides of the uptake, in small furnaces it will be
more economical in construction to dispense with the central chanmiber 16 and let
the tubes extend across the uptake to the jacket on each side, in which case the
colder air would pass from the left or right side of the jacket, as most convenient,
and return to the same side, and thence to the furnace. This would be -advan--
tageous where the uptake was narrow, the modification being merely to dispense
with one upper and lower set of the nests; the air would travel right across
instead of to the central chaniber only.
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. In an economizer for furnaces, in combination with an uptake for the gases
and smoke, a jacket surrounding said uptake in proximity to the furnace, means
for passing air thereto; of nests of tubes placed horizontally on opposite -sides
within the uptake, a central chamber dividing the said tubes, other nests of tubes
arranged beneath the first ones, and communicating from the central chamber to
the jacket beneath parting walls 18, which divide the lower tubes off 'from the
upper ones, as specified.
2. In an economizer for furnaces, having an uptake to receive the heated gases
generated thereby, the combination of a jacket surrounding the lower part of
the uptake, and means for distributing cold air around the said uptake within the
jacket, of a central chamber 16 arranged in the uptake of a nest of tubes 15 on
opposite sides of the central chamber, said tubes communicating between the
jacket and the central chamber, and of other nests of tubes 14 arranged beneath
the tubes 15, which also connect between the jacket and the central chamber, and

page_text: parting plates 18, which divide the outer ends of the nests of tubes, as and for
the purposes specified.
3. In combination with an uptake, having a jacket arranged thereon and means
for passing a flow of air to the jacket; of a central chamber 16 arranged in the
uptake, perforations in the opposite walls of the chamber 16, and the outer side
walls of the uptake nests of tubes, or pipes passed through said perforations
communicating between the jacket and the chamber 16, and horizontal parting
walls 18 placed between the jacket and the uptake dividing the outer ends of
the upper and lower nests of tubes, so that the incoming air flow will pass through
the upper tubes to the central chamber and back through the lower nests of tubes
to the jacket, as specified.
4. In an economizer having an uptake and a jacket surrounding the same, the
combination of nests of tubes 14 and 15 extending horizontally across the uptake
and communicating with the opposite sides of said jacket, a horizontal parting
wall 18 arranged to divide the upper nest of tubes from the lower one, on the side
where the air is introduced into and expelled from said tubes, as specified.
Dated this 14th day of November A.D. 1898.
WILLIAM G. TRETHEWEY,
Agent.