Note: Descriptions are shown in the official language in which they were submitted.
~332~
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TITLE OF THE INVENTION
HEAT CONDENSING FURNACE WITH DE-INTENSIFIER TUBES
BACKGROUND OF THE INVENTION
The present invention is related -to an improved high
efficiency heat condensing furnace or heat exchanger of the type
disclosed in U.S. Patent Nos. 4,311,191 and 4,311,192, each
issued on January 19, 1982 in the name of Gerry Vandervaart, as
well as other improvement patents also issued in the name of
Gerry Vandervaart under U.S. Patent Nos. 4,420,034; 4,429,734;
4,442,890; 4,415,023; 4,441,546; 4,458,665; 4,461,345; and
4,825,664. The contents of these patents, particularly the first
two and the last, are incorporated herein by reference particu-
larly with respect to presently conventional struc-tural and
functional characteristics of such prior art heat exchangers or
condensing furnaces which are, obviously, compatible wilh the
condensing furnace of the present invention. U.S. Patent Nos.
4,311,191 and 4,311,192 each disclose a heat exchanger which
includes conventional components such as a compressor, indoor and
outdoor coils, blowers associated with the coils, one or more
reversing/expansion valves and appropriate tubing or conduits
such that the heat-exchange medium/refrigerant can flow
in opposite directions through associated conduits during the air
conditioning/cooling mode of operation on the one hand and the
heating or heat-augmenting modes of operation on the other.
These conventional heat exchangers operate in the heat-
augmenting mode through the ignition of a gas burner which
provides a very intense flame in a combust:iorl charllber within an
outdoor A-coil. Such conventional heat excllan(lers ar~ extremely
B efficient up to approximately five (S) ton.s, ar~ his efficiency
is attributed primarily to the fact t,hat the outdoor A-coil i.s
- - - 2033240
relatively short in height (20 inches high), and the relatively
intense heat of the flame i$ "trapped" within the confines of the
A-coil. Though the efficiency is extremely high, the A-coil can
become damaged because of the intense heat of the flame primarily
because the aluminum fins of the A-coil cannot conduct heat to
the copper tubes passing therethrough (conducting the refriger-
ant) as fast as the aluminum fins absorb the heat from the flame.
At the moment of combustion, the flame generated by the burner
within the combustion chamber of the A-coil reaches a temperature
of approximately 2200F. If complete combustion and absorption
is not achieved, the efficiency drops and unburned gas will
escape into the atmosphere. However, if the heat/Btu's are
absorbed by the aluminum fins faster than the fins can conduct
the heat therethrough and to the copper tubing, the coils will
dry out creating an acidic condition which deteriorates the
aluminum fins reducing the efficiency and life thereof. Under
optimum conditions, the A-coil should absorb all of the heat from
the flame as immediately as possible causing the flue gases to
cool and condense so that the condensation on the aluminum fins
of the A-coil prevents deterioration thereof. Under this optimum
condition, the flame is absorbed-through the condensation which
keeps the exterior of the aluminum fins "wet", prevents drying
and acidic deterioration, and assures high efficiency because of
maximum Btu absorption and A-coil life.
Obviously, one way to achieve absorpt;ion in the absence of
drying out of the coil and preventing damage to the aluminum fins
thereof would be to minimize the heat of the flame. I-lowever, if
the heat of the flame were reduced, the out;pul; of t;he over~l]
condensing furnace would be reduced. Accordirlgly, (lesirably an
optimum condition is that of mainl;a;ning ~h~ rlame at maxilnul-
2 0 3 3 2 4 0 ~`~`~ --- -
intensity in conjunction with a relatively small A-coil which
can absorb the heat from the flame and transfer the heat as
fast as it is absorbed to achieve efficiency, yet do so
without drying the aluminum fins of the coil. In other words,
the intense heat of the flame must be absorbed and cooled such
that the flue gases are cold enough to allow condensation to
form on and wet the coil and prevent deterioration thereof.
SUMMARY OF THE INVENTION
A construction in accordance with the present
invention includes a gas condensing furnace comprising an
outdoor coil burner assembly, the outer coil burner assembly
including first and second outdoor heat exchanger means for
conducting a refrigerant therethrough; the first outdoor heat
exchanger means including a first outdoor coil defining a
first refrigerant series flow path having a refrigerant inlet
and a refrigerant outlet; the first refrigerant series flow
path establishes refrigerant flow in a first general
direction, the second outdoor heat exchanger means including a
second outdoor coil defining a second refrigerant series flow
path having a refrigerant inlet and a refrigerant outlet; the
second refrigerant series flow path establishes refrigerant
flow in a second general direction generally opposite to the
first refrigerant series flow path first general direction,
means for generating relatively intense heat relative to
ambient temperature which is adapted to be absorbed by the
first outdoor coil, the second outdoor coil being positioned
generally between the first outdoor coil and the intense heat
generating means for de-intensifying the relatively intense
heat of the intense heat generating means whereby less intense
heat is absorbed by the first outdoor coil and the refrigerant
flowing therethrough, the first and second outdoor coils and
-- 3 --
B
2033240
the refrigerant inlets and outlets thereof being in series
communication with each other, a compressor and an indoor
coil, refrigerant conduit means for placing an outlet of the
compressor in refrigerant communication with an inlet of the
indoor coil, and further refrigerant conduit means for placing
an outlet of the indoor coil in refrigerant communication with
the second outdoor coil inlet and for placing the first
outdoor coil outlet in refrigerant communication with an inlet
of the compressor.
In keeping with the foregoing, the present invention
solves the problem of maintaining high efficiency through
~ heat absorption in the absence of fin/coil
deterioration by providing a heat de-intensifier mechanism in
the combustion chamber which reduces the temperature of the
flue gases created by the burner flame and permits
condensation to be formed upon the aluminum fins of the coil
to prevent acidic deterioration thereof, while at the same
time maintaining extremely high Btu absorption. Preferably
the de-intensifier mechanism is one or more de-intensifier
tubes which are located between the gas burner and the A-coil
such that the extremely intense heat of the flame/flue gases
are absorbed by the de-intensifier tubes, thereby reducing the
temperature of the flue gases reaching the A-coil. The de-
intensifier tubes are part of the refrigerant system and the
liquid refrigerant is transformed into its vapor state by the
intense heat of the flames when absorbed through the de-
intensifier tubes. The absorption of the flue gases by the
de-intensifier tubes occurs so instantaneously by the
refrigerant dùring the flow thereof through the de-intensifier
tubes that the de-intensifier tubes are maintained at a
constant temperature of approximately 50F. and are,
B - 3a -
3b
2033240
therefore, bathed in moisture/condensation and cannot,
therefore, corrode because heat
-- ~ 2~332~Q
absorption takes place through this moisture. The same approxi-
mate 50F. flue gases also partially escape outwardly beyond the
de-intensifier tubes through the sides of the A-coil, and again
because of the relatively cool temperature (50F.), the aluminum
fins of the A-coil sides are kept moist and the acidic corrosion
thereof cannot occur through the condensation/moisture. Thus,
the de-intensifier tubes, which are preferably constructed from
copper, absorb the intense heat of the flame/flue gases, prevent
the same from drying out the de-intensifier tubes and/or the
aluminum fins of the A-coil sides, and thereby maintains aluminum
fin integrity and high heat absorption efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic view of an overall heat condensing
furnace or heat exchanger of this invention, and illustrates an
indoor coil, a compressor, a pair of reversing valves, and an
outdoor A-coil defined by opposite sides and a pair of de-
intensifier tubes between which is located a tube burner and
below which are a plurality of drain tubes.
FIGURE 2 is a cross-sectional view taken generally along
llne 2-2 of Figure 1, and illustrates the generally sinusoidal
configuration of one of the de-intensifier tubes, the reduction
in diameter thereof from top-to-bottom, and a lower drain tube.
FIGURE 3 is a cross-sectional view taken generally along
line 3-3 of Figure 1, and illustrates another of the de-
intensifier tubes, the generally sinusoidal configuration
thereof, the reduction in diameter of portions of the de-
intensifier tube from top-to-bottom, and a drain tube underlying
the same.
~t~3~3~:4~
FIGURE 4 is a schematic view of an overall condensing
furnace/heat exchanger of the present invention, and illustrates
another outdoor A-coil which includes a de-intensifier mechanism
formed by de-intensifier tubes of a generally flattened configu-
ration.
FIGURE 5 is a cross-sectional view taken generally along
line 5-5 of Figure 4, and illustrates the sinusoidal configura-
tion of one of the de-intensifer tubes and an underlying drain
tube.
FIGURE 6 is a cross-sectional view taken generally along
line 6-6 of Figure 4, and illustrates another of the de-intensi-
fier tubes, the sinusoidal configuration there, and an underlying
drain tube.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A novel condensing furnace, heat exchanger or heat-exchange
system constructed in accordance with this invention is illus-
trated in Figure 1 of the drawings, and is generally designated
by the reference numeral 10.
The condensing furnace 10 includes an outdoor coil 15 which
is an A-coil which is housed in a housing 16 having generally
parallel side walls 17, 18, a top wall 20, opposite end walls
(not shown), and an interior draft fan 21 which when energized
creates an upwardly directed draft, as indicated by the upper
unnumbered headed arrows, which draw exhaust and combustion gases
upwardly through the housing 16 and outwardly thereof through
apertures 22 of the top wall 20. The A-coil 15 is supported in a
condensation pan 23 of a conventional constructiorl. ~I'he conden-
sation pan 23 is spaced from the housing 16 t;o permit com~)ustiorl
air to be introduced into t;he hollorrl o~ Ih~ hol~sing l~, ir~ e
(~ 2033240
manner indicated by the unnumbered headed arrows associated
therewith.
The A-coil 15 includes generally identical rectangular coils
24, 25 each formed by copper tubing generally designated by the
reference numeral 26 and aluminum fins 27 conventionally secured
to the exterior of the tubes 26 along the length thereof frorn
front-to-back in a conventional manner. As is more fully
described in the latter-identified patents, the refrigerant
passing through the copper tubes 26 absorbs the heat/Btu's from
the flames/flue gases F emanating from a gas tube burner 30
having two rows of orifices (not shown) along the bottom thereof.
The flames F are directed by the orifices generally in opposite
directions away from each other and toward the respective coils
24, 25, as is readily apparen-t in Figure ]. Gas is introduced
into the tube burner 30 through a conduit 31 in a converltional
manner and is ignited by an electronic igniter (not shown), as is
also conventional. As the refrigerant circulates through
the copper tubes or tubing 26 of the coils 24, 25, the heat/Btu's
of the flames/flue gases F are absorbed and eventually the liquid
Freon is transformed into a liquid vapor and subsequently a gas
which is discharged over a line 60 to an inlet port "4" of an
auxiliary reversing valve 61. The refrigerant gas exits the "3"
port of the auxiliary reversing valve 61 and flows through a line
62 to a port "2" of a main reversing valve 63 exiting a port "3"
thereof through a line 64 to a compressor 65. Vapor exits the
compressor 65 over a line 66, enters a port "1" of the rnain
reversing valve 63, exits a por-t "4" of ttle main reversing valve
B 63 and enters an indoor coil 70 through a l-ine 6~. The indoor
coil 70 is associated with a t)lower (not shown) whi-h absorbs t~e
heat from the refrigerant passing thro~yh the coil 70 to ~eat
20~3~
whatever interior, such as a house, is associated with'-the indoor
coil 70. The refrigerant exits tlle indoor coil 70 over a line
71, enters a port "1" of the auxiliary reversing valve 61, exits
a port "2" of the auxiliary reversing valve 61, and the refriger-
ant, now in its liquid phase, returns to the A-coil 15-via a line
72. The operation just described is more specifically set forth
in the first two and last listed patents herein, as-well as in
U. S. Patent 4,995,241, issued February 26, l991, entitled
High Efficiency Heat Exchanger in the name of Gerry
Vandervaart.
Since the temperature of the flame/flue gases F is in the
vicinity of 2Z00F., this high intensity heat is pre~erably
dissipated or de-intensified before reaching the coils 24, 25 and
particularly the aluminum fins 27 thereof. It has been found
that the aluminum fins 27 which are pressed on the copper tubing
do not transfer the heat/Btu's absorbed from the flue gases F to
the copper tubing 26 and the refrigerant circulating there-
in as fast as the heat is absorbed from the flames F. Because of
the latter, condensation cannot form on the exterior of the
aluminum fins and the aluminum fins 27 dry out creating an acidic
condition which deteriorates the aluminum fins 27 shortening the
life thereof and, obviously, reducing the overall efficiency of
the condensing furnace 10.
In accordance with the present invention, means, generally
designated by the reference numeral 40, are disposed at a posi-
tion adjacent the flames F issuing from the tubular burner 30 to
de-intensify the relative intense heat of the flame F' whereby
less intense heat is absorbed by ttle coi.l.s 2~., 25 and s~ec:i~i.cal-
B ly through the aluminurll:r ins 27 an(l the col)r)er t~Jblng ~6 ~he~eofby the refrigerant flowing throuyh the latter. ~h~ mearls ~0 -is
~0~240
`
effectively a heat exchanger in the form of a pair of copper de-
intensifier tubes 41, 42 (Figures 2 and 3, respectively), each of
which is of a generally sinusoidal configuration, as viewed in
side elevation (Figures 2 and 3).
The sinusoidal de-intensifier tubes 41 and 42 each include
an upper cylindrical tube portion 43, a next adjacent cylindrical
tube portion 44, a subsequent cylindrical tube portion 45, and a
lowermost tube portion 46. The tube portions 43 through 46 are
generally in parallel relationship to each other and the
transverse cross-sectional size thereof decreases from top to
bottom, as is evident in Figures 2 and 3. This reduction in
diameter of the tube portions 43 through 46 is effected by
reducing tubes 5. through 53. The purpose of the reduction in
diameter of the tube portions 43 through 46 from top to bottom is
to permit condensation which forms upon the exterior surfaces of
these tube portions to drop downwardly upon the next lowermost
tube portion(s) to assure that all of the tube portions will be
kept wet. For example, condensation which forms upon the tube
portions 43 of the sinusoidal deintensifier tubes 41, 42 will
drip downwardly upon the underlying tube portions 44, etc.
The liquid refrigerant in the line 72 enters both sinusoidal
de-intensifer tubes 41, 42 through the front end, as viewed in
Figure 1, of the lowest tube portion 46, travels upwardly through
the successive tube portions 45, 44 and 43, as indicated by the
unnumbered headed arrows associated therewith, and exits the
uppermost tube portions 43 of both sinusoidal de-intensifier
tubes 41, 42 through tubes 54, 55 which are connected to t;he
associated copper tubes 26 of the respecti.ve coils or .side coi].s
24, 25. The refrigerant flows through the copper tubes ~6 i.n a
downward direction, as is indicated by the cros.seci unnutrlhered
2G332~
headed arrows associated therewith in Figures 2 and 3, with
crossover occuring by crossover tubes 56 until eventually the
refrigerant exits the tubing 26 at the bottom of the side coils
24, 25 through tubes 58, 59. The refrigerant exiting the tubes
58, 59 enters larger cylindrical drain tubes 81, 82 (Figure 2).
The drain tube 81 is connected at the end opposite the tubes 58,
59 by a tube 83 (Figure 2) to an enlarged cylindrical drain tube
84 which is in turn connected to the conduit 60. The cylindrical
drain tube 82 is likewise connected by a tube 85 (Figure 3) to a
drain tube 86 which is connected at its forward end to the
conduit 60. Thus, the refrigerant which enters the drain tube 81
flows from front-to-rear, as viewed in Figure 1, enters the
conduit 83, and returns from rear-to-front through the drain tube
84 exiting the latter into the conduit 60. Similarly, the
refrigerant entering the drain tube 82 flows from front-to-rear
(Figure 1), enters the tube 85 (Figure 3), and returns from rear-
to-front through the drain tube 86 entering the conduit 60.
When the condensing furnace 10 is in its heat-augmenting
mode, the reversing valves 61, 63 are positioned to effect
refrigerant flow in the manner heretofore described relative to
Figure 1. The igniter (not shown) ignites the gas which in turn
generates the flames F having a relatively intense temperature of
approximate 2200F. However, the heat/flue gases F radiating
from the burner 30 are absorbed virtually instantaneously by the
copper de-intensifier tubes 41, 42 and the refrigerant flowing
therethrough under the influence of the compressor 65. The
refrigerant initially entering the lowermost tubular portions 46
of the de-intensifier tubes 41, 42 is in it;s liqui~ state but
eventually is transformed into it~s v~por state a.s it ~r~ve]s
upwardly through the various tube por~ior).s an(l exits ~h~ upp~r-
3 3 ~ ~ ~
most tube portions 43 through the tubes 54, 55. Since the de-
intensifier tubes 41, 42 are placed directly in the path of the
flames F and the natural tendency thereof to go in the direction
proportionate to its intensity, the flames F and specifically the
Btu's thereof are absorbed virtually instaneously by the
refrigerant flowing through the de-intensifier tubes 41, 42
reducing the temperature of the flue gases virtually instaneously
to 50F. which is cold enough to allow condensation to form not
only on the de-intensification tubes 41, 42 but also upon the
coils 24, 25 and specifcally the aluminum fins 27 thereof. Thus,
the exterior surfaces of the sinusoidal de-intensifier tubes 41,
42 are kept "wet" with condensation, as are the fins 27, and the
latter will not dry out, thus avoiding the heretofore mentioned
undesired acidic condition which would deteriorate the aluminum
fins 27. Thus, though flue gases F will, obviously, also pass
through the de-intensifier tubes 41, 42 and the Btu's will be
absorbed by the refrigerant flowing through the tubes 26 of the
coils 24, 25, the condensation on the fins 27 of the latter
assures that heat absorption takes place through such moisture/
condensation and corrosion of the fins 27 will not occur. Hence,
in the heat augmented mode of operation of the condensing furnace
10, the relatively small coil 15 (8" high, 20" long and 12" per
side) is extremely efficient and when operating as aforesaid, the
interior of the housing 16 exteriorily of the A-coil 15 has no
trace of heat at an ambient of 50 F.
The bottom edge (unnumbered) of the side coils or coils 24,
25 are also slightly (7l-) above the drain tubes 8~, 8~., 82 and 86
and the side coils 24, 25 are also spaccd approxilna~ely 1." away
from side walls or panels 17, 18 and ~)e periphery arl(J hottotll
(unnumbered) of the condensation pan 23. The l~tt~r is provided
~ 20~24a
so that when combustion takes place to create the flame/flue
gases F, air is drawn up evenly along both sides of the coils 24,
25 interiorly thereof into the area of the tube burner 30 and is
forced upwardly without losing any heat/Btu's to the ambient.
The latter can be augmented by energizing the draft fan 21,
although this is not necessary at temperatures of 40F. and
lower. However, because of the extremely low flue gas tempera-
ture discharge (approximately 50F.), the draft fan 21 should be
energized above 40F. Also, the crossover or crossover tubing 56
is preferred because the burner 30 will not generate an even
flame F at opposite sides thereof and, therefore, even a slight
coil pressure drop can cause heat to be drawn up faster on one
side than the other. Thus, the crossover 56 assures equal
updraft of the flue gases F and more efficient absorption of the
heat/Btu's thereof by the refrigerant flowing through the de-
intensifier mechanism ~0 and the coils 24, 25.
It should also be appreciated that the flames F do not
simply come directly laterally outwardly of both sides of the
burner 30, but radiant heat is also reflected downwardly which
under normal circumstances could create heat loss. However, the
refrigerant exiting the tubes 58, 59 flows into the drain tubes
81, 84, 86 and 82 which are located directly beneath the
reflected heat, absorbing the same, and transferring the absorbed
reflected heat back to the compressor 65. Thus, virtually all of
the heat generated by the burner 30 is totally absorbed rendering
the overall condensing furnace 10 extremely efficient.
The condensing furnace 10 is, of course, operat;ive in the
absence of the generation of ttle flame ~ in the Stri~t h~at punlp
mode of operation thereof, and the r~verSi ng va I v~ ~; I, 63 ~an be
appropriately manipulated for cooling/air conditior~irl~ opera-
1~ 2033240
tions, in the manner fully described in U. S. Patent4,995,241.
Reference is now made to Figures 4 through 6 of the drawings
which illustrates another gas condensing furnace of the present
invention which is generally designated by the reference numeral
110 .
The condensing furnace 110 includes an outdoor coil 115
which is an A-coil which is housed in a housing 116 having
generally parallel side walls 117, 118, a top wall 120, opposite
end walls (not shown), and an interior draft fan 121 which when
energized creates an upwardly directed draft, as indicated by the
upper unnumbered headed arrows, which draw exhaust and cornbustion
gases upwardly through the housing 116 and outwardly thereof
through apertures 122 of the top wall 120. The A-coil 115 is
supported in a condensation pan 123 of a conventional construc-
tion. The condensation pan 123 is spaced from the housing 116 to
permit combustion air to be introduced into the bottom of the
housing 116 in the manner indicated by the unnumbered headed
arrows associated therewith.
The A-coil 115 includes generally identical rectangular
coils 124, 125 each formed by copper tubing generally designated
by the reference numeral 126 and aluminum fins 127 pressed onto
the exterior of the tubes 126 along the length thereof from
front-to-back, as viewed in Figure 4, in a conventional manner.
The refrigerant passing through the copper tubes 126 absorbs the
heat/Btu's from the flames/flue gases 1' emanating from a gas
tube burner 130 having two rows of orifices (not sllowrl) alon(~ t~ e
B bottom thereof. The flames ~' are directed by tl--e ori r; ces
generally in opposit,e directions away ~rolll ~ach ~t,h~ and ~owar(l
the respective coils 124, 125, as is readily apparent in Figure
`- 2033`2~
4. Gas is introduced into the tube burner 130 through a conduit
131 in a conventional Inanner and is igrlited by an electronic
igniter (not shown), as is also conventional. As tlle refrigerant
circulates through the copper tubes or tubing 126 of the
coils 124, 125, the heat/Btu's of the flames/flue gases 1' are
absorbed and eventually the liquid refrigerant is -transformed
into a liquid vapor and subsequently a gas which is discharged
over a line 160 which circulates in the same manner as that here-
tofore described relative to Figure 1.
Since the temperature of the flarne/flue gases F' is in the
vicinity of 2200F., this high intensity heat is preferably
dissipated or de-intensified before reaching the coils 124,lZ5and
particularly the aluminurn fins 127 thereof. In accordance with
the invention of Figures 4 through 6, means 140 are disposed at a
position adjacent the flames F' issuing froln t~e tubular burner
130 to de-intensify the relative intense heat of the flame F'
whereby less intense heat is absorbed by the coils 124, 125 and
specifically by the aluminum fins 127 and the copper tubing 126
thereof. The means 140 is effectively a heat exchanger in the
form of a pair of copper de-intensifier tubes 141, 142 (Figures 5
and 6, respectively), each of which is of a generally sinusoidal
configuration, as viewed in side elevation (Figures 5 and 6).
The sinusoidal de-intensifier tubes 141 through 142 each
include an upper, shallow, flat, rectangular tube portion 143; a
next adjacent shallow, flat, rectangular -tube portion 144; a
subsequent shallow, flat, rectangular tube portion ~45; and a
lowermost, shallow, flat, rectanyuJar l;ubc port;iorl l4(~ e lut)e
portions 143 through 146 are genera]ly in parall el relationship
to each other lengthwise froln front-to-t)ack, as is IIIOSt readily
evident in Figures 5 and 6 of the ~rawings. I he tube r~ortions
3~24a
143 through 146 are also angularly tilted relative to each other,
as viewed from either the front or the back, as is most apparent
from Figure 4. Furthermore, selected ones of the tube portions
143 through 146 can differ in transverse cross-section or size
relative to each other to permit condensation on an uppermost
tubular portion to drip downwardly and fall upon a lowermost tube
portion, as was described more fully heretofore relative to the
de-intensifier mechanism 40 of Figures 1 through 3. However, the
primary differences between the de-intensifier mechanisms 40 and
140 are threefold: (1) the relatively shallow, flat, rectangular
configuration of the tube portions 143 through 146 present a
relatively large, flat cross-sectional area to the radiating
flames, flue gasses _ which increases the absorption efficiency;
(2) the angular tilting of the tube portions 143 through 146
defines a generally inclined flow path for condensation to flow
along the underside (and the upperside) of each tube portion 143
through 146 before dripping downwardly upon the next lowermost
tube portion; and (3) both de-intensifier tubes 141, 142 are
totally housed within the sides 124, 125 of the A-coil 115 which
slgnificantly reduces the exiting of flue gases directly upwardly
between the contacting upper ends (unnumbered) of the coils 124,
125 assuring that the flue gases essentially must pass through
the coils 124, 125. These three factors further increase the
overall efficiency of the condensing furnace 110, as compared to
the condensing furnace 10. In addition, the tube portions 141
through 146 are selectively connected together by shallow, flat,
rectangular reducing tubes 151 through ]55 for ~he purpo.sc
heretofore described. Ilowever, in this case the ~ub~ porl;ions
143, 143 are of a smaller cross-section than the underlyir)g tube
portions 144, 144, whereas the tube por~ions 145, 145 are of a
lG
- ~5 ~3:~240
larger cross-section than the underlying tube portions 146, 146.
This is done to more efficiently absorb the Btu's from the flue
gases F' while still assuring that the condensation from each
uppermost tube portion will drip downwardly upon the underlying
next adjacent tube portion because of the inclination or tilting
thereof, as is best illustrated in Figure 4 which illustrates
condensation or droplets C dripping in this fashion from the tube
portions 143 downwardly upon the tube portions 144 and from the
tube portions 145 downardly upon the tube portiors146. In this
fashion all condensation which forms on the exterior surfaces of
the tube portions 143 through 146 will drop downwardly upon the
next lowermost tube portion to assure that all of the tube
portions 143 through 146 will be kept moist with condensation and
preclude the undesired acidic/corrosive conditions earlier noted.
The condensing furnace 110 is otherwise operational in the
manner heretofore described relative to the condensing furnace
10 .
Although a preferred embodiment of the invention has been
specifically illustrated and described herein, it is to be
understood that minor variations may be made in the apparatus
without departing from the spirit and scope of the invention, as
defined in the appended claims.
1~
