Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF T~E I~VENTIO~
The present invention relates to metal panels having ;~
a system of internal tubular passageways disposed between
spaced apart portions of the thickness of the panel. Said
panels possess utility in heat exchange applications wherein
a heat exchange medium is circulated through said passage-
ways A particular application of said panels resides in
devices utilizing solar energy, and specifically, solar energy
absorbing devices for elevating fluid temperature.
It is well known that the radiation of the sun can ;
be collected as a source of energy for heating or cooling or
for direct conversion to electricity. Heating and cooling ~
depend upon collection of rays of solar energy in a fluid ;
heat transfer system. The heated fluid is pumped or allowed
to flow to a place of utilization for the thermal energy it ~ ~'
has acquired.
In certain areas of the world, solar energy is
the most abundant form of available energy if it could be
harnessed economically. Even in more developed areas of
the world, the economic harnessing of solar energy would ~ -
provide an attractive alternative to the use of fossil
fuels for energy generation.
One of the problems attending the development
of an efficient system for the conversion of solar energy
resides with the structure and design of the solar energy
absorbing device, or solar collector. This solar
collector generally comprises a rectangular plate-like
structure possessing channels or passageways for the
circulation of the energy absorbing fluid medium.
Conventionally, these panels have comprised a pair of
opposed expanded passageways, known as
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headers, which are placed at opposite ends o~ the panel, and
are connected by a plurality of tubular passageways which are
often in parallel relation with respect to each other. These
passageways, as well as the headers themselves, have generally
been disposed at right angles with respect to each other and
in parallel relation with respect to the horizontal and
vertical dimensions, respectively, of the panel.
The aforementioned configuration suffers from certain
deficiencies, in that fluid flow tends to encounter pockets of
stagnation which cut down on the efficient circulation of solar
energy. Further, as a partial result of the turbulent operating
conditions attending heat exchange applications, various entrained
gases tend to collect in the passageways, with the result that air
locks which greatly inhibit flow and reduce the maximum fluid
circulation capacity of the panel are often formed. Such
difficulties as reduced ~luid velocity, nonuniform flow and
excessive pressure drop have been characterized as resulting from
the lnefficiencies of such prior art designs. It is, therefore,
toward the alleviation of the above difficulties that the present
invention is directed.
SUMMARY OF THE INVENTION
In accordance with the present invention, a h~at
exchanger is provided which exhibits improved operating
efficiency and particular utility in solar energy applications.
In accordance with a specific embodiment of the
invention, there is provided a heat exchange panel possessing
a system of internal tubular passageways, said tubular passage-
ways de~ining at least three generally tapered longitudinally
extended headers, at least two of said longitudinally extended
headers extending substantially the length of said panel, a
connecting header located at one end of said panel transverse
to and interconnecting longitudinally extended headers, and
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generally transversely extended connecting portions of said
passageways, said connecting portions extending between
longitudinally extendèd headers, at least one fluid entry means
longitudinally extending from at least one of said headers and
at least one fluid exit means longitudinally extending from
another of said headers, wherein said longitudinally extended
headers include a centxally located header offset by a pair
of laterally displaced headers.
~he panel of the present invention may also comprise
a system of tubular passageways for a heat exchange medium defining
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at least two longitudinally extended headers extendlng sub-
stantially the length of the panel, a connecting header
located at one end of the panel interconnecting the longi-
tudinally extended headers and lying in a direction trans-
verse thereto, generally transversely extending connecting
portions of said passageways extending between the respective
longitudinally extended headers, and entry and exit portions
ext~nding from at least two of said headers to provide
ingress and egress openings for the heat exchange medium.
In a preferred embodiment the panel o~ the present ,;
invention comprises at least two longitudinally extended
headers of essentially triangular shape,, wherein a single,
centrally located inlet header is located between a pair of
laterally displaced opposed outlet headers, and said inlet
and outlet headers are connected at one end thereof by a
transversely extending, substantially rectangularly shaped
connecting header, and entry and exit portions are respect-
ively provided in extension from said inlet header and said
connecting header to provide ingress and egress openings '~
for said heat exchange medium.
The panel of the present invention may possess a
wide variation in the configuration of the ~luid distribut-
ing pattern to account for variations in size and utility of
the particular panel to be prepared. Thus, the panel of the
present invention may employ connecting portions disposed at
an angle of at least 91 with respect to the longitudinal
dimension of the panel to assist in fluid flow. Also, the
headers of the present invention may be provided with bonded
portions to assist in fluid distribution and to enhance
structural stability and resistance to rupture under pressure,
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As indicated above, the preferred embodiment of
the present invention utilizes a metal panel having a
system of internal fluid passageways, conventionally
painted blackl as will be described in more detail herein-
below. The concepts of the present invention may, howeverl
also be advantageously utilized in heat exchangers generally,
such as, for example, using extrusions. Since the concepts
of the present invention are particularly advantageous in
metal panels having a system of internal fluid passageways,
the present invention will be speciically described here- ~;
inbelow utilizing this type of system.
Accordingly, it is a principal object of the
present invention to provide a metal panel for use in heat
exchange applications which enables the efficient and
economical transfer of heat energy.
It is a further object of the present invention
to provide a metal panel as aforesaid which is particularly
suited for use in a solar energy collector system.
It is yet a further object of the present inven-
~O tion to provide a metal panel as aforesaid which is capableof achieving uniform flow at high velocity of a heat
exchange medium and a reduction in pressure drop within
the passageways of a solar energy collector.
Further objects and advantages will become
apparent to those skilled in the art as a detailed des-
cription proceeds with reference to the following
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagram showing schematically the
manner in which the panels of the present invention can be
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employed.
Figure 2 is a perspective view of a sheet of
metal having a pattern of weld-inhibiting material applied
to a surface thereof.
Figure 3 is a perspective view of a composite
metal blank wherein a second sheet of metal is superimposed
on the sheet of metal shown in Figure 2 with the pattern of
weld-inhibiting material sandwiched therebetween.
Figure 4 is a schematic perspective view showing
the sheets of Figure 3 being welded together while passing
through a pair of mill rolls. `~
Figure 5 is a top view showing the panel of the
present invention having internal tubular passageways dis-
posed between spaced apart portions of the thickness of
the panel in the areas of the weld-inhibiting material.
Figure 6 is a sectional view taken along lines
6-6 of Figure 5.
Figure 7 is an alternate view showing a variation
in the tube configuration similar to the view o~ Figure 6,
Figures 8, 9, 10 and 11 are top views showing
alternate embodiments of the present invention.
DETAILED DESCRIPTIO~
In accordance with the present invention, the ~;
foregoing objects and advantages are readily attained.
The panels of tha present invention ar~ provided
with a system of parallel headers connected by fore-
shortened connecting por~ions which greatly facilitate
flow efficiency and heat exchange.
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As noted earlier, the present invention is
directed to the problems of nonuniform flow at reduced
velocity, and fluid blockage resulting from the turbulent
conditions under which heat exchange panels are operating.
Specifically, the panels are conventionally employed in
either the horizontal or the vertical plane whereby fluid
entering the panels is under pressure developed by a cir-
culating pump or the like, and in the instance of vertical
installation, additionally by the force of gravity. The
fluid is split within the panel into a plurality of channels
through which it passes to effect the heat exchange
phenomenon. A problem which has arisen in this arrange-
ment results from the turbulence of Eluid movement through
the panel which results in a pressure drop between the
headers and the connecting portions thereof. This pressure
drop causes air pockets to form and tends to impede the
movement of fluid. This further results in a reduction
in fluid flow and velocity which deleteriously a~fects the
efficiency of the panel. The provision of a panel employ-
ing a plurality of longitudinally extended headers incombination with connecting passageways of reduced length
in accordance with the present invention is believed to
cure the aforenoted deficiencies.
The panels of the present invention are prefer-
ably utilized in a solar heating system as shown in Figure 1
wherein a plurality of panels of the present invention 10
are mounted on roof 11 of building 12 with conduits 13 and
14 connected in any convenient fashion to the equipment in
the building,with the connections not shown. Thus, for
example, cold water may go into conduit 13 from the
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building 12 by means of a conventional pump or the like.
The water f~ows along common manifold 13a and is distri-
buted into panels 10. me water flows through panels 10,
is heated by means of solar energy, is collected in common
manifold 14a and flows into conduit 14. The heated water
is then stored or utilized in a heat exchange system inside
the building in a known manner. Naturally, if desired, the
water flow may be reversed with the cold water entering via
conduit 14 and collected via conduit 13. Alternatively,
the solar heating unit of the present invention may be
used or placed in any suitable environment, such as on the
ground with suitable fasteners to prevent displacement by
wind or gravity. me solar heating unit of the present
invention may be used for residential heating purposes,
such as in providing hot water in a residential environ-
ment. For example, three panels of the present invention
having dimensions of 8 feet x 4 feet would efficiently
supply an average household of four with hot water for
home use. Alternatively, the solar panels of the present
invention may be conveniently used for heating water for
swimming pools or for preheating water for domestic gas
or oil fired domestic hot water heaters. The fluid is
preferably retained in a closed system with the water in
the system heated in the solar unit and delivered into an
insulated cistern or container so that the heated fluid
may be stored up during sunshine for use on cool cloudy
days or at night when the heating of the fluid in the
panel will not be of sufficient degree to provide the
desired heat at the point of use.
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A thermostat not shown is desirably installed at
the top of the solar heater and this thermostat may be set
to turn on a circulating pump whenever the temperature
reaches a predetermined reading. The pump will then pump
the water through the system as generally outlined above,
As indicated above, the present invention contem-
plates a particularly preferred panel design for optimum
efficiency in a solar heating system as described above.
The metal panel or plate of the present invention is
desirably fabricated by the ROLL-BO~D~3process as shown in
U. S. Patent 2,690,002. Figure 2 illustrates a single
sheet of metal 20 as aluminum or copper or alloys thereof,
having applied to a clean surface 21 thereof a pattern of
weld-inhibiting material 22 corresponding to the ultimate
desired passageway system. Figure 3 shows the sheet 20
having superimposed thereon a second sheet 23 with a pattern
of weld-inhibiting material 22 sandwiched between the units.
The units 20 and 23 are tacked together as by support welds
24 ~o prevent relative movement between the sheets as they
are subsequently welded together as shown in Figure 4 by
passing through a pair of mill rolls 25 to form welded
blank 26, It is normally necessary that the sheets 20
and 23 be heated prior to passing through the mill rolls
to assure that they weld to each other in keeping with
techniques well known in the rolling art.
m e resultant blank 26 is characterized by the sheets
20 and 23 being welded together except at the area of the
weld-inhibiting material 22, The blank 26 with the unjoined
inner portion corresponding to the pattern of weld-inhibit-
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ing material 22 may then be softened in any appropriatemanner as by annealing, and thereafter the blank may be
cold rolled to provide a more even thickness and again
annealed. The portions of the panel adjacent the weld~
inhibiting material 22 are then inflated by theintroduction
of fluid distending pressure, such as with air or water, in
a manner known in the art to form a system of internal
tubular passageways 30 corresponding to the pattern of
weld-inhibiting material, as shown in Figure 5. The
passageways 30 extend internally within panel 10 and are
disposed between spaced apart portior.s of the thickness of
said panel. Thus, panel 10 comprises a hollow sheet metal
panel or plate having a system of fluid passageways 30 for
a heat exchange medium extending internally therein. If
the passageways are inflated by the intro,duction of fluid
distending pressure between flat die platens, the resultant
passageways have a flat topped configuration 31 as shown in
Figure 6. If, on the other hand, passageways 30 are formed
without the presence of superimposed platens, t~e resultant
passageway configuration has a semicircular shape 32 as
shown in Figure 7.
As shown in Figure 5, the passageways 30 include a
plurality of headers comprising inlet header 33 and outlet
headers 34, all of which are longitudinally extended to
substantially the length of panel 10. At one end of panel 10,
generally rectangular, transversely extending connecting header
35 is provided which links up headers 34~ In addition, headers
33 and 34 are connected by connecting portions 36, comprising
a plurality of relatively short tubular passageways extend-
ing in a direction substantially
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transverse to the longitudinally extended headers. Prefer-
ably, connecting portions 36 are provided as a plurality of
spaced, parallel individual tubes running between header
33 and headers 34, which provide the optimum situs for the
heat exchange phenomenon. Also, passageways 30 include
entry portion 37 and exit portion 38 extending, respectively,
and in opposite direction to each other, from inlet header
33 and connecting header 35, to provide ingress and egress
openings for the heat exchange medium
In accordance with the present invention as illus-
trated in Figure 5, headers 33 and 34 are generally tri-
angular in shape and are situated respecting each other
whereby the inlet header 33 and the outlet headers 34
possess respective areas of the greatest width at opposite
ends of panel 10. The relationship of the configurations
of headers 33 and 34 has been found to enhance uniformity
of fluid flow, as the differential in velocity of flow
between the area of header 33 adjacent the entry portion
and the area furthest therefrom is provided for by the
reduction in header size at the furthest point. Llkewise,
the differential in flow experienced in outlet headers 34
is compensated for by the corresponding differential in
header width as fluid builds up to exit the panel. The
problem of pressure drop has been dealt with by the pro-
vision of connecting portions 36 which are foreshortened
in relation to headers _ and 34, as it is believed that
the employment of said connecting portions in lengths
exceeding those of the corresponding header structures con-
tributed to a differential in fluid pressures. Thus,
connecting portions 36, though not specifically limited:
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to a particular dimension, are generally provided in lengths
substantially less than that of the longitudinal dimensions
of header structures 33 and 34. The residence time of fluid
within connecting portions 36 is thus drastically reduced,
and the opportunity for pressure drop to occur is corres-
pondingly diminished. Fluid thus draining from headers 33
and 34 is able to flow evenly into connecting header 35
where it is transferred out of panel 10 through exit
portion 38.
As can be appreciated, the present invention is
broadly applicable in a wide variety of designs embodying
various modifications to suit the ap~lication of the panel.
Thus, for example, Figure 8 depicts a panel ~0 which
employs substantially the same arrangement of headers as
set forth in Figure 5, with the exce~tion of the provision
of connecting portions 41 in a direcl:ion slightly inclined
toward the direction of fluid flow in the horizontal
dimension of panel 40. Specifically, connecting portions
41 may be provided to define an angle of at least 91 as
~0 measured in the direction of fluid flow with respect to
the longitudinal dimension of panel 40, Connecting portions
41 are inclined at an angle of at least 91, and preferably
92 to 100, measured with respect to the longitudinal
dimension of the panel. Though this disposition of the
connecting portions is illustrated herein, it is not
obligatory and does not form a limitation on the scope of
the present invention, as connecting portions may be
employed at right angles to the longitudinal dimensions of :
the panel, The primary feature of the present invention is
rather the disposition of the various header structures in
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the longitudinal dimension in association with the fore-
shortened connecting portions, as illustrated in Figure 5,
to improve fluid distribution and flow~
A further modification useful in accordance with
the present invention is illustrated in Figure 9. In this
figure, panel 50 is provided which is substantially identical
in configuration to panel 10 illustrated in Figure 5, with
the addition of a plurality of bonded portions 51 located
intermittently in inlet header 52 and outlet headers 53.
Bonded portions 51 are provided to assist in the inter- -
ruption of fluid flow, which serves to reduce the deleterious
effects of excess turbulence. Also, bonded portions 51
provide additional strength and structural integrity to
headers 52 and 53 which increases their resistance to rup- '
ture under pressure during the employment of panel 50 in a
heat exchange system. Though illust~ated as essentially
circular islands, bonded portions 5 may be provided in a
wide variety of shapes, such as parallel elongated struc-
tures defining internal channels, not shown, which would
further serve to assist in directing fluid flow within the
headers. The foregoing is illustrative of a wide variety
of modifications which can be made to the bonded portions
_ within the scope of the invention, and the invention
should not be construed as limited thereby.
Referring now to Figure 10, an alternate embodi-
ment employing essentially the basic structure of the
present invention is illustrated. Panel 60 can be seen to
be of substantially identical configuration to that of panel
10 in Figure 5, with the exception that two inlet headers 61,
each possessing entry portions 62 are provided which corres~
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pond to outlet headers 34 of panel 10. Fluid thus may enter
from two locations into headers 61 where it will pass through
foreshortened connecting portions 66 to collect within
centrally locatea outlet header 63n Outlet header 63 is
identical in configuration to inlet header 33 shown in
Figure 5, and headers 61 and 63 are illustrated as of essen-
tially triangular shape with their areas of greatest-width
located at opposite ends of panel 60~ Fluid draining into
outlet header 63 passes out of panel 60 through exit portion
64 corresponding to entry portion 37 in Figure 5. ~s in
Figure 5, connecting header 65 ~ corresponding to connecting
header 35 is provided between headers 61 adjacent entry
portions 62 and serves in this capacity to assure the equal
distribution of flow of incoming heat exchange fluid, in
the event,for example, the flow through one of ports 62
exceeds that of the other. Naturally, the panel of Figure
10 may be modified by the provision of inclined connecting
portions 66 and the inclusion within headers 61 and 63 of
a plurality of bonded portions, as disclosed and discussed
20 above with respect to Figures 8 and 9
Figure 11 illustrates an alternate embodiment of
-the present invention wherein the panel 70 comprises a fluid
distribution pattern defined by the placement of the pattern
of the present invention as illustrated in Figure 5 in an
abutting relationship to itself. Thus, panel 70 comprises
a centrally located header 71 serving as the inlet header
for heat exchange fluid which is substantially identical in
displacement and configuration to header 33 of Figure 5~
Fluid entering header 71 through entry portion 72 is then
30 directed through a plurality of bonded portions 73 which
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extend essentially transversely to communicate with lateral
headers _ . Lateral headers 74 are likewise extensions of
headers 34 by the provision of identical structures in abutt-
ment thereto. Headers 74, like header 71 are essentially tri-
angular in shape, however, unlike header 71, possess their
area of greatest width at a location approximately inter-
mediate their length. Fluid collecting within headers 74 is
then directed through connecting portions 73 which flow into
central outlet header 75 beariny identical configuration to
inlet header 71 Both headers 71 and 75 are identical in
shape to header 33 in Figure 5 and are thus essentially tri-
angular structures. Fluid collecting in header 75 is then
permitted to leave panel 70 through exit portion 76, which
corresponds in configuration-and size to entry portion 72~
As can be seen from the Figure, the embodiment of panel 70
does not possess a transversely extending rectangular con-
necting header, as no utility for such a structure exists
within the context of this panel configuration
It should be noted that in all cf the foregoing
embodiments of the present invention, the connecting portions
of the fluid passageways have been illustrated in parallel,
spaced apart relationship to each other. This configuration
is preferred but is not obligatory, as connecting portions
may be employed which may vary somewhat in size, width, and ~-`
direction which would be suitable for use in accordance with
the present invention
Though the foregoing description has set forth
certain illustrative embodiments, many alternative panel
designs may be envisioned by one skilled in the art in accord-
ance with the concepts disclosed and described above, and theinvention is accordingly considexed to encompass all such
modifications,
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