Note: Descriptions are shown in the official language in which they were submitted.
This invention relates generally to solar energy
collectors.
The invention has been devised primarily in connection
with solar energy collectors for swimm~ing pool heating systems, ~,
5 although the invention is not limited to this particular appli- '
cation. A typical solar energy collector for a swimming pool -
heating system comprises a generally rectangular panel having
water flow passages extending longitudinally thereof, and two
headers sealed to respectively opposite ends of the panel. The
10 panel and headers may be plastic extrusions. All solar energy
collectors by their very nature are exposed to severe operating ~;
conditions in use, due not only to the effects of solar radia-
tion, but also to extremes of climate.
An object of the present invention is to provide
15 improvements relating to solar collectors which permit an array
of collectors to be secured to a support surface and which
accommodate longitudinal expansion and contraction of the col-
lectors due to changes in temperature.
According to one aspect of the invention there is
20 provided a solar collector array which includes a plurality of
solar collectors disposed side by side on a support surface.
Each collector includes a generally rectangular panel having a
plurality of fluid flow passageways extending longitudinally
thereof, and a pair of elongate headers disposed at respec~
25 tively opposite ends of the panels and each including a main
fluid flow passageway which extends longitudinally of the
header and which communicates with the fluid flow passageways
in the panel. Means is provided coupling the headers of
~ .
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adjacent collectors together to permit fluid flow therebetween
and resilient attachment means is provided securing the coupling
means to said support surface at attachment points while per-
mitting longitudinal expansion and contraction of the panels
5 with respect to said attachment points.
In order that the invention may be more clearly
understood, reference will now be made to the accompanying
drawings which illustrate a number of preferred embodiments of
the invention.
In the drawings:
Fig. 1 is a perspective view showing an array of
solar collectors installed on the roof of a building, for example,
as part of a swimming pool heating system;
Fig. 2 is a dlagrammatic illustration of the manu-
15 facture of the panel used in the collectors of Fig. 1;
Figs. 2A and 2s are cross-sectional views on lines ``
A-A and B-B of Fig. 2~respectively;
Fig. 3 is a diagrammatic illustration of the
manufacture of the headers used in the collectors of Fig. l;
, Fig. 4 is a transverse sectional view of the
header shown in manufacture in Fig. 3;`
Fig. 5 shows the header of Fig. 4 after a subsequent
step in the manufacturing operation;
Fig. 6 is a sectional view on line VI-VI of Fig. 5;
, ; :
- Fig. 7 is a view similar to Fig. 5 but showing the -
panel assembled to the header preparatory to fusing of the ~anel
in place;
Fig. 8 is a view similar to Fig. 7 showing the
panel fused to the header;
Fig~ 9 is a sectional view on line IX-IX of Fig. 8;
Fig. 10 is a longitudinal sectional view through an
end portion of the header of Fig. 8 showing an end fitment in
place on the header preparatory to fusing of the header and fitment;
Fig. 11 is an exploded perspective view showing the
end fitment of Fig. 10 and an associated gasket used inside the
fitment;
Fig. 12 is a view similar to Fig. 10 showing the
end fitment and header fused together;
Fig. 13 is a cross-sectional view generally on line
XIII-XIII of Fig. 1 and shows strip connectors used to couple
adjacent solar collectors in the array;
Fig. 14 is an exploded perspective view corresponding
to Fig. 13 and showing additional components used for coupling
the headers of adjacent collectors;
Fig. 14A is a detailed perspective view of part
o~i Fig. 14;
Fig. 15 is a longitudinal sectional view through
one of the collectors shown in Fig. 1 and is taken generally ~;
along line XV-XV; and appears on the same sheet as Figs. 1,2,2A and 2B;
Fig. 16 is a diagrammatic illustration showing a
number of the collectors nested together for transportation and
appears on the same ~heet as Figs. 1,2,2A and 2~;
~ig. 17 is a side e~evation of a solar collector
according to a further embodiment of the invention; and,
A , ::`
39
, .
Fig. 18 is an underneath elevational view of part of
the collèctor of Fig. 17.
Referring first to Fig. 1, an array of solar energy
collectors is generally indicated at 20 on the roof 22 of a
S building 24. In this particular embodiment, six collectors 26
are used and are coupled together side by side as will be more
particularly described later. Flow and return lines for coupling
the collectors to the remaining components of a swimming pool
heating system are indicated at 28 and 30 respectively. A vacuum
breaker is indicated at 32.
Referring to the collector which appears at the left
hand side of the array in Fig. 1 by way of example, each collector
includes a generally rectangular panel 34~ and a pair of
elongate headers 36 and 38 coupled to respectively opposite end
portions of the panel. Panel 34 has a plurality of longitudinally
extending fluid flow passageways (not shown in Fig. 1) which
extend between the headers and through which water flows between
the headers when the heating system is in use.
Fig. 2 illustrates the formation of panel 34. The
panel is formed by a section severed transversely from a
continuous thermoplastic extrusion. In this particular embodiment,
the plastic material is a co-polymer of polypropylene and polyethelene
having normal additives and ultraviolet stabilizers. Part of a
conventional extruder is indicated at 40 in Fig. 2 and has an
extrusion head 42 from which issues a continuous extrudate 44.
The extrudate is in the form of a relative thin and flat sheet
having a plurality of generally rectangular passageways extending
longitudinally thereof.
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2351
-- 6
Fig. 2A shows the cross-sectional shape of the
extrudate immediately downstream from the head 42. The
passageways are denoted 46 and are separated by walls 48 which
extend generally normal to the top and bottom surfaces of the
sheet. Sheet 44 is severed transversely at appropriate positions
to provide a re~uire~ length for forming the panels (as panel
34)of solar collectors. The extrudate could be severed
substantially in the form in which it leaves the extrusion head
(after hardening and cooling) in which case the fluid flow
passageways of the solar collector panels would be generally of
the form shown in Fig. 2A. However, for reasons which will be
explained later, it is preferred to cause the walls 48 between
the fluid flow passageways to assume a buckled or zig-zag
configuration in the final panel. This is achieved by passing the
extruded sheet through the nip between a pair of rolls 50
(Fig. 2) arranged to slightly reduce the overall thickness of the
sheet. This causes the walls 48 to buckle and assume generally
the configuration indicated at 48' in Fig. 2B. Rolls 50 are
positioned at a distance from the extrusion head such that the
~0 extrudate will not have fully cooled and hardened hefore it
reaches the rolls, so that the extrudate will set in its final
form with the walls 48 buckled. It will of course be appreciated
that the buckling action will take place in random fashion and
that the walls will not necessarily assume the particular shapes
~5 shown in Fig. 2B.
The buckled wall configuration has two primary
advantages in the finished collector. Firstly, it provides for
freeze protection in the event that the collector is inadvertently `-
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3~3
exposed to freezing temperatures without having first been drained
of water. The buckled internal walls in the panel of the
collector allow the panel to expand in thickness as the water
freezes without bursting the panel. Secondly, the buckled walls
promote turbulence in the fluid (usually water) flowing through
the passageways 46 and thereby promote improved heat transfer
between the fluid and ambient air.
As indicated above, it is not essential (although
p~eferred) that the internal walls in the panel be buckled. In
any event, it will be appreciated that the extruaed sheet 44 can
be severed transversely into appropriate lengths for forming
successive panels for use in assemblying soIar collectors on a
continuous basis.
Reference will now be made to Figs. 3-6 of the
drawings in describing the formation of the headers (as headers
36 and 38-Fig.l). The headers are also in the form of extrusions
and Fig. 3 shows a conventional extruder 52 having an extrusion
head 54 for producing an extrudate 56. Fig. 4 shows the cross-
sectional shape of the extrudate 56. The extrudate is formed
continuously and is severed into lengths appropriate to the required
header length. In this particular embodiment the headers are of
substantially the same transverse dimension as the panel of the
collector although in other cases it may be necessary to make
the headers longer.
As seen in Fig. 4, the extrudate includes a main
generally cylindrical portion 58 defining a main fluid flow
passageway 60 which extends longitudinally of the header. An
integral channel shaped portion 62 projects outwardly from
cylindrical portion 58 and defines a narrow slot 64 disposed -
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3~
generally tangentially with respect to~the cylindrical portion
58. At the inner end of slot 64 is an upright wall 66 which
closes the bottom of the slot in the as-moulded configuration of
the extrudate. Slot 64 is dimensioned to closely receive an
end portion of the panel of the collector. In assembling the
collector, the panel is inserted into slot 64 until it reaches
wall 66 so that the wall in effect defines the fully inserted
position of the panel. However, before the panel is inserted,
wall 66 is formed with apertures for providing fluid communication
between the longitudinal passageways in the panel and the main
fluid flow passageway 60 of the header. As shown by Figs. 5 and 6,
these apertures take the form of elongate slots 68 formed right
through wall 66. The slots may be formed using a conventional
routing tool. The form and arrangement of the apertures in wall
66 are believed to be non-critical except that the total cross-
sectional area of all of the apertures should approximately e~ual the
total cross-sectional area of all of the fluid flow passageways
in the panel. At the same time, it is believed that a series of
apertures is to be preferred over a continuous opening for the
reason that the portions of the wall which remain between the
apertures impart additional strength to the header. In one
particular embodiment, five of the slots 68 were provided in a
two foot length header.
Referring back to Fig. 4, slot 64 has inner faces
70 and 72 which co-operate with opposéd faces 74 and 76 at the
end portion of the panel when the panel is inserted in slot 64.
Integral sealing strips 78 and 80 are formed on the faces 70 and
72 respectively of slot 64. These sealing strips are co-extruded
with the main extrudate 56. The strips are of the same material
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g-
as the main extrudate except that they have magnetically
excitable particles dispersed therein.
In this particular embodiment, the main header
extrudate 56 is made of the same material as the extrudate 44
for forming the panel of the collector (a copolymer of polypropylene
and polyethelene with appropriate stabilizers). The strips
78 and 80 are made of the same copolymer with iron particles
dispersed therein.
Reference will now be made to Fig. 7 which shows
the header of Figs. 4 and 5 and a panel assembled together. By
way of example, it will be assumed that the header and panel are
those denoted 36 and 34 respectively in Fig. 1. It will be
seen that panel 34 is inserted in to the slot 64 in the header
until it abuts the remainder of wall 66. The sealing strips
78 and 80 inside the slot overlie the faces 74 and 76 at the end
portion of the panel within the slot. Having assembled the
header and panel ln this way, the sealing strips 78 and 80 are
subjected to the effect of a high frequency magnetic field
having characteristics selected to excite the particles in the
sealing strips to an extent sufficient to cause the strips to
fuse with the panel and header in the areas of the opposed
~aces. As shown in Fig. 7, the magnetic field is applied using
a conventional radio frequency generator of the type used for
induction welding. The generator is indicated generally by ,i
25 reference numeral 82 and includes an induction coil (not shown) `~
in which a radio frequency magnetic field is induced. The
magnetic field is applied to the sealing strips by way of two
transmission heads 84 and 86 applied to opposite sides of the
channel shaped portion 62 of the header extrusion. The heads ,~
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-- 10 --
are in the orm of rectangular section copper tubes which are
hollow and through which cooling water is passed. The tubes
are coupled to the generator 82 by leads 88 and 90 and to one
another by a lead 92. The tubes and header will be supported in an
appropriate jig during this operation and appropriate ancillary
equipment will be provided for circulating water through the
tubes~ However, since this equipment forms no part of the present
invention, it has not been illustrated.
The magnetic field produced by generator 82 is applied
to the sealing strips 78 and 80 at a frequency and intensity and
for a period of time sufficient to effect the required fusion of
the panel to the header. In practice, it is found that the sealing
strips tend to melt and flow inwardly and outwardly of slot 6
and to essentially merge into the opposed faces of the panel
and header. In one particular example, a frequency of 7,000 c.p.s.
was found to be adequate. In any event, after a suitable period
of time (as determined by experimentation) the generator 82 is
switched off. However, the tubes 84 and 86 are allowed to remain
in contact with the header until the assembly has cooled to an
extent sufficient to permit it to be handled. Fig. 8 shows the
panel and header fused together at this time. The portion of the
panel inside the header slot has been shown in effect "merged"
into the portion 62 of the header as in fact occurs in practice.
Fig. 9 is a sectional view through the merged portion
~5 of the panel and header and shows the configuration o~ the
fluid flow passageways(denoted 46'~in this area. It will be
seen that the upper and lower walls of each passageway have
distorted inwardly to a slight extent as indicated at 9~ and 96
to form protrusio~s or "bumps" which partially restrict the
- . . :. . . . . ........ .
~3L~ d~
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-- 11 --
passageway. These protrusions have been found to occur naturally
as a result of the fusing operation described previously. In
practice, they have been found to have the advantage of acting
as a control on the flow of fluid through the passageway. Also,
they serve to improve the rigidity of the header. It has further
been found that it is possible to control the size of the protrusions
94 and 96 by appropriately controlling the duration for ~Jhich
the magnetic field is applied to the sealing strips 78 and 80.
Thus, by extending the duration compared with that which was used
to form the configuration shown in Fig. 9, it is possible to
cause the opposing protrusions to merge and define what is
essentially an hourglass shape as indicated by dotted lines at
98 in Fig. 9. This provides for a further restriction in the
flow of fluid through the passageway, which may be required in
some circumstances. It will of course be appreciated that the
same effect will occur in all of the passageways of a particular
header.
It will also be appreciated that while the
preceding description refers specifically to the fusing of the
panel to the header 36, a similar operation will be performed
to fuse the other end of the panel to the other header (38). The
fusing operations used in each case need not be the same. For
example, it might be desirable to provide different fluid flow
control conditions ln one header compared with the other. After
~5 the panel and headers have been fused cogether, end fitments are
attached to the ends of the headers by what is basically a very
similar fusing operation. That operation will now be described
more particularly with reference to Figs. lO, ll and 120
2,39
,
- 12 -
Fig. 10 shows an end portion ~f one ~f the headers
in londitudlna1 section. For convenience it will be assumed that
header 36 has been shown and that the other header will be the same.
Part of the panel34 bonded to the header is also visible as is
part of the U-shaped portion 62 of the header. An end fitment
to be fused to the heaaer is indicated generally at 100 and is
shown in perspective in Fig. 11. Similar fitments are also shown
after the fusing operation at the ends of adjacent solar collectors
in Fig. 14. Referring primarily to Fig. 11, the fitment includes
an outer portion 102 of cylindrical shape and an inner portion
104 having an inner surface 106 shaped to conform with the
external profile of header 36 and having an open outer end at
108. The fitment is a one piece moulding in the same plastic
material as the panel and headers. As can be seen from Fig. 10,
the fitment is placed over the end of the header so as to fit
snugly around its external shape and with the outer end portion
102 projecting outwardly from the header generally coaxially
therewith. The presence of this cylindrical portion permits the ;~
collector to be readily coupled to other similar collectors or
to other components in a solar heating system.
Fig. 11 also shows a gasket 110 which is shaped
to fit inside the inner end portion 104 of fitment 100. Gasket
.
110 is of the same form as the sealing strips 78 and 80 used
for fusing the panel to the headers. Thus, the gasket is made
of the same copolymer as the fitment but has magnetically
excitable particles dispersed therein. The gasket is placed
inside the fitment before the fitment is applied to the end of
the header,and the gasket is visible at 110 in Fig. 10.
'
~.2~;~3~
- 13 -
By carefully examining Fig. 10, it will be seen that
the inner surface 106 of end portion 104 of ~itment 100 is relieved
inwardly of an outer rib 112 to provide a relief space 114 around
the outer end portion of header. Part of rib 112 is also visible
in Fig. 11. This space is provided to allow the gasket 110 to
flow into the space between the end portion of the header and the
fitment as the gasket melts, for improved fusing of the fitment
to the header.
Having assembled the fitment to the header in the manner
shown in Fig. 10, gasket 110 is ~ubjected to the effect of a high
frequency magnetic field in much the same fashion as the sealing
strips were subjected to the magnetic field in the embodiment of
Fig. 7. As in that case, a radio frequency generator is employed
to produce the magnetic field and is applied to the components
to be fused by way of water cooled "heads" in the form of copper
tubes. The two heads used in the case of the end fitments are
indicated at 116 and 118 in Fig. 10 and will be coupled to the
generator (not shown) as in the embodiment of Fig. 7. Tube 118
is shaped to define a circular configuration in which it extends
~0 completely around the end portion 102 of the end fitment, while
tube 116 is shaped to conform with the external shape of the
end portion 104 of the fitment. Each tube will be made in two `~
sections hinged together to permit it to be fitted to and
removed from the fitment.
~5 As in the case of Fig. 7, the tubes or "heads" and
the components to be fused will be mounted in a suitable jig
while a high frequency magnetic field is applied to the gasket `
causing it to melt and fuse into the header and fitment generally
in the same manner as described above. In this case, a mandrel
- ~.Z~L2~3~
- 14 -
120 is also used inside the fitment to prevent the gasket flowing
into the interior of the fitment and/or header.
Fig. 12 shows the end product of the fusing operation.
It will be seen that the header and fitment have fused together
and become essentially one unit.
It will be appreciated from the foregoing
description that the solar collector produced by the method
described will essentiall~ become a one piece integral assembly
and it is thought that the risk of leakage will practically have
been eliminated. In the particular embodiment described, the
components of the collector were referred to as being made of
the same copolymer. It will of course be appreciated that other
thermoplastic materials ma~ be used. Further, it should be
noted that the components to be fused together need not
essentially be of the same material so long as the sealing strips
or gaskets employed are of a material capable of fusing with the
materials of the components. ~or example, where two components
to be fused are of two different materials, the sealing strip
or gasket used between those components could be a copolymer
~0 of the materials of the components.
It should also be noted that the end fitments for
the headers of the solar collector need not essentially be
attached b~ a fusing operation. In some instances it might, -
for example, be convenient to use solvents or adhesives or other
2~ expedients for attaching the fitments.
Reference wlll now be made to Figs. 13 and 14 in
describing further features of applicant's solar collector. Fig.
13 shows connector strips used between adjacent collectors in an
- 15 -
array such as that shown in Fig. 1. The strips are designed to
connect the panels of adjacent collectors so that the array
presents a generally flat external surface, and also to hold down
the panels onto their support surface so as to minimize the risk
of liftïng of the panels under severe wind conditions.
In Fig. 13, the panels of two adjacent collectors
are indicated as 34' and 34". Two similar connector strips 122
and 124 are provided between the panels. The strips are shown in
perspective in Fig. 14. Referring to strip 122 as typical of
both strips, it will be seen that the strip includes a generally
flat base portion 126 which lies flat on a support surface (in
the case of strip 122). Strip 124 is identical but shown ~nverted
so that its base portion is in fact uppermost in use. In any
event, strip 122 is shaped to define on one side, a continuous
laterally`directed channel 128 dimensioned to frictionally
receive an edge portion of the collector panel 34'. Adjacent the
opposite side of the stripr a rib 130 of substantial~ly circular
shape in cross-section protrudes upwardly from the base portion
and extends longitudinally thereof parallel to its outer edge~
Inwardly of rib 130 a channel 132 of generally complimentary
shape e~tends parallel to rib i30. The rib 130 and channel 132 are ~ `
designed so that when two similar strips (as strips 122 and 124)
are inverted with respect to one another they can be snap
fitted together with the rib on one strip snapped into the channel
on the other as shown in Fig. 13. The assembly of the two strips
r~ 3LZ 33
- 16 -
will then define two laterall~y directed channels for engaging
opposed edges of adjacent collector panels.
The lowermost strip in an assem~ly is secured to
a support surface by fasteners such as the screws indicated at
133 in Fig. 14. Referring back to Fig. 13, a shallow notch 134
extends longitudinally of the strip, between the rib 130 and the
channel 132 and acts as a guide for locating the screws. Openings
could be proviaed in the strip for receiving the screws but
generally this is not necessary. Immediately below the groove
is a shallow channel 136 capable of receiving caulking compound
or other sealant. A strip of sealant will be introduced into the
channel before the screws are introduced and the strip will be
placed on a roof or other support surface and screws driven through
at appropriate locations. The sealant will then prevent leakage
at the position of any screw irrespective of its location. When
a particular strip has been installed in this way, its companion `~
strip can then be engageù with the associated panel and snap
fitted to the already installed strip as discussed above. The
strips themselves will preferably be of a length equal to the
exposed length of each panel between the associated headers. Of
course, shorter lengths of connector strip may be appropriate in
some situations. The intention is that the connector strip will
be extruded in continuous lengths which can be cut to size as
required.
Fig. 14 shows the adjacent panels 34' and 34" in ~
perspective and also shows portions of their top headers, denoted
36l and 36" to ~hich end fitments 100' and 100" have been
attached. The fitments have respective cylindrical inner end
portions 102' and 102" disposed substantially in alignment with
,: ~. . : : ~
39
- 17 -
one another. The collectors are~shown in exploded positions in
Fig. 14 and will, as installed, be substantially closer together
so that the portions 102' and 102" will be substantially in
abutment. A coupling sleeve 138 is fitted over the portions 102'
and 102" as the collectors are brought together. Conventional
gear clamps 140 and 142 are then tightened around the coupling
sleeve 138 to clamp the sleeve to the end fitments 100' and 100"
and provide an effective liquid tight seal between the adjacent
headers. Sleeve 138 has an integral tab 144 which projects
generally tangentially from the sleeve itself and which has an
aperture for receiving a screw 146 (Fig. 14A) for securing the ,
sleeve to the roof or other support surface. The sleeve and
integral tab are made of the material known as EPDM. This is a
flexible and resilient material and has the advantage that tab
144 can stretch and contract to accommodate expansion and
contraction of the panel due to changes in temperature. Although
not essential, it is preferable that the solar collectors be
installed on a hot day so that each collector will be substantially
in its fully expanded position as installed. The tabs 144 can
then 5tretch to accommodate contraction on the colder days.
Coupling sleeves similar to sleeve 138 will be provided between
~djacent collectors and at the outer ends of the end-most
collectors in an array and at both the top and bottom headers. ~;
The use of these coupling sleeves in conjunction with the
25 connector strips 122 and 124 will assure that the collectors - ` -
are all firmly held down to the roof or other support surface
so that the risk of shifting of liftiny of the panels is
minimized.
~ 21;23~
- 18 -
Fig. 15 is a longitudinal sectional view through
one of the collectors in the array denoted 20 in Fig. 1. It will
be seen that the headers 36 and 38 are arranged with their slots
or mouths (denoted 64' and 64" respectively) disposed on opposite
sides of a plane P joining the axes of the main fluid flow
passageways of the headers. In other words, the bottom header
38 is inverted compared with the position it would be expected
to adopt if the panel were to lie flat on the roof surface. This
inversion has two primary advantages. Firstly, it permits several
solar collectors to be "nested" together on top of one another
so as to occupy minimum space for transportion and/or storage
as shown in Fig. 16. Secondly, in the event that "weathering"
of the collector is noticed on one side, the collector can be
reversed and inverted so that the side of the collector which
was formerly exposed is now against the roof surface. This
effec`tively doubles the life of the collector. -
The panel 34 of the collector is extremely flexibleand can readily be deformed to accommodate this reversed header
configuration during installation. In practice, it has been
found that the distance D between the lower header and the point
of first contact of the panel with the roof surface will be as
little as one foot. It has also been found that, due to its
resilient nature, the panel will readily change its shape as
required when the collector is reversed and inverted.
At this stage it should be noted that, although
the reversed header arrangement has been described in connection
with the features of the invention discussed above, it is not
essential that the reverse header arrangement be used with the
other features. Also, the fusing process described can
. .
. . : . . . . .
- 19 ~ 3~
of course be used with any appropriate header orientat~Qn.
Figs. 17 and 18 illustrat~ ~ further embodiment
which, again, is applicable both to solar collectors of any of
the forms disclosed herein and to other forms of collectors
comprising two headers with a panel extending therebetween.
Conventionally, solar collectors must be mounted on a
substantial support including a relatively large and flat surface
such as`the roof of a building (Fig. 1). In other cases, a
specially constructed rack must be provided for supporting the solar
collectors. The embodiment illustrated in Figs. 17 and 18
is intended to avoid the need for such a structure. In Fig. 17,
a solar collector is shown in side view and incl~des an upper
header 148, a lower header 150 and a panel 152. In this case,
the headers and the panel are of the form described above although
this is not essential. Each header has a generally tangentially
extending slot or mouth which receives the panel so that the
panel is offset but parallel to a plane containing the axes of
the main flow passageways in the headers.
~ccording to this aspect of the invention, a honey-
comb structure made of cardboard is applied to the under surfaceof panel 152 and the "cells" of the honeycomb are filled with a
rigid polyurethane foam. The cardboard honeycomb structure is
generally indicated 154 and defines cells 156 disposed with
their axes normal to panel 152. Thus, the cells extend outwardly
away from the panels. The foam bonds to the panel and has the
effec. of imparting substantial rigidity to the collector so
that the collector in itself becomes a rigid unit which is
self-supporting. This in turn eliminates the need for extensive
.
. ~ , : . . .. ~
.
: ~'- . , ~ . ~ . , ; .
- 20 - ~ 2~ ~ ~g
supportlng structure for an array of panels. As seen in Fig. 17,
the collector is s~own supported in an inclined position above
the ground surface (indicated at 158). The upper collector is
supported by an inclined wooden beam 160 (e.g. of 2" x 8" size)
nailed between two vertical support posts, one of which is
indicated at 162 (e.g. of 4" x 4" size) set in the ground. Header
148 is attached to beam 160 by a nail 164 driven through an
integral tab which projects outwardly from the header in the
m~nner of tab 144 on the coupling sleeve shown in Fig. 14. A
similar tab 166 on the lower header is secured by a stake 168
into the ground. It will be appreciated that other similarly
rigid collectors may be coupled side by side with the collector
shown in Fig. 17 and supported on the same beam 1~0.
The polyurethane foam backing on the panel will be
applied by inverting the collector before installation, placing
the honeycomb on the inverted panel and spraying liquid
polyurethane into the honeycomb cells. If necessary, the surface
of the panel can be treated by conventional corona spark discharge
techniques to improve the adhesion of the polyurethane foam. These
techniques will be essentially the same as the techniques
employed for treating plastic materials prior to silkscreen
printing and will not therefore be described in detail.
The cardboard honeycomb 154 referred to may of course
be replaced by equivalent structures. It is not essential that -;
the structure should be of cardboard or that the cells in the
structure be honeycomb shape. The structure should merely
provide a matrix for receiving polyurethane foam and providing
a reasonable depth backing on the panel. Cardboard is a
particularly convenient material because of its relative low cost
. . .; ,, . , ., : . ~ ~. : ~
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but in other cases it may be possible to use, say, plastic
mouldings or grids for receiving the polyurethane foam.
It will of course be appreciated that the preceding
description relates to specific embodiments of the invention and
that many modifications are ~ossible within the broad scope of
the invention. It is also to be understood that the various
aspects of the invention disclosed herein need not necessarily
by used together as described but may find application even in
association with other forms of solar collectors.
Referring in particular to the emboidment best
illustrated in Figs. 3 to 8, it is to be noted that the sealing
strips 78 and 80 need not be co-extruded with the headers. In
other embodiments the strips could be formed on the panel or
made as separate strips subsequently secured to or placed
between the surfaces to be fused.
This application is a division of Canadian Patent
Application Serial No. 339,866, filed November 13, 1979.
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