Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02541139 2006-03-28
GREENHOUSE INSULATION SYSTEM
The present invention relates to the field of greenhouses and controlled
environment agriculture (CEA).
Generally speaking, a greenhouse is a building constructed for the practice of
indoor horticulture or agriculture. Traditionally, the walls and roofs of
greenhouses have
been constructed of glass or similar transparent material such as transparent
plastic
panels. This permits sunlight to directly illuminate plants, and permit them
to grow.
Systems have been proposed, for instance as shown in US Patent No. 5,655,335
to allow
the roof of a traditionally constructed transparent greenhouse to open to
permit the plants
being grown therein to become hardier, thereby increasing the success rate of
transplants
from the greenhouse to a natural environment. In US Patent No. 5,655,335,
longitudinally extending roof panels are paired together in v-shaped pairs
that extend the
length or width of a greenhouse. Each arm of the 'V' slantingly abuts the 'V'
next to it,
to define a series of peaks running the length or width of the greenhouse.
Each 'V'
shaped pair of panels is hinged together at the base of the 'V' and provided
with
mechanical means to draw the arms of the 'V' inward. It will be understood,
then, that
when one or more V shaped pairs is closed up in this way, the roof will be
opened, and
the natural atmosphere permitted to circulate in the open greenhouse.
It is, moreover, known to use a plurality of inflatable tubes, arranged
parallel to
each other to construct an insulating partition in a greenhouse. In US4290242
(Gregory),
inflatable clear polyethylene tubes are arranged in longitudinal lines in a
greenhouse to
provide an insulating layer. The tubes are inflated to lean against each other
and provide a
continuous insulating ceiling structure when there is no sunlight, and
deflated to hang
vertically and provide passages between the tubes when the sun is shining.
A similar system is shown in US4352259 (Smith et al.), which also provides
that
the ends of the longitudinally extending tubes are mounted on racks, whereby
the tubes
may be drawn to the side of the greenhouse. Other patents that show the use of
insulating
structures made up of parallel inflatable tubes can be seen in US4301626
(Davis et al.),
US600171 (Davis) and US6442903 (Herbert).
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The present invention, therefore, provides a greenhouse insulation system that
has, at its core, a novel retractable insulation module for use in a
greenhouse. Each
module has a pair of rectangular light-weight insulating panels that are
hinged together
along a common lower edge. The panels can be pulled together to permit air
flow, and
heat flow, between the panels, preferably by means of a bellows created by
joining the remaining edges of the panels by means of a gas impermeable
membrane, and selectively
inflating or deflating the bellows defined by the panels and the membranes.
Alternatively, the panels may be opened or closed by means of cables, wires, a
rack and
pinion system, or any other mechanical means, as will be obvious to one
skilled in the art.
An air space is provided in the greenhouse between the insulated ceiling
panels of the
present invention, and the roof (which may be transparent or translucent), of
the
greenhouse. It will be understood, moreover, that the present invention is
applicable to
any building having roof glazing. Therefore, as used herein the word
'greenhouse' should
be interpreted to mean any building with areas of roof glazing in which it may
be desired
to install the system of the present invention.
The downwardly facing surfaces of the insulating panels of the present
invention
will ideally be coated with a reflective material, which will maximise the
efficiency of
the natural light reaching the plant canopy in the greenhouse.
In a broad aspect, then, the present invention relates to an insulation system
for
use in a greenhouse, comprising at least one insulation panel adapted to be
mounted in
the ceiling of a greenhouse, and means to move said at least one panel from a
closed
position to an open position, whereby when said panel or panels are closed,
air below
said panels remains in the area of said greenhouse below said panels, and when
said panel
or panels are open, air below said panels can move to a space in said
greenhouse above
said panels.
In another broad aspect, then, the present invention relates to a selectively
operable ceiling panel for use in a greenhouse, comprising a bellows defined
by a pair of
longitudinally extending insulation panels hinged together along a common
lower edge,
and joined together along their end and upper edges by an air-tight membrane
to define a
bellows the evacuation of which will cause said panels to move together. The
panels will
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remain in this vertical position until the air is no longer being evacuated,
at which time
the panels will spread apart.
In drawings that illustrate the present invention by way of example:
Figure 1 is a perspective view partly in phantom of a collapsible insulation
panel
module according to the present invention, in its closed condition; Figure 2
is a perspective view a collapsible insulation panel module of Figure 1,
in its open condition;
Figure 3 is a perspective view of a panel module attached to either a fan or
an air
blower;
Figure 4 is a perspective schematic view of a series of modules, in open
condition;
Figure 5 is a similar view to that of Figure 4, with the modules in closed
condition;
Figure 6 is a cross-section, through line VI-VI in Figure 3; and
Figure 7 is a detail view of the bottom panel of a plenum, in place.
Figure 8 is a front view of a preferred form of central supporting structure
according to the present invention.
Figure 9 is a front view of an alternate form of central support structure
according
to the present invention.
Figure 10 is a front view of another alternate form of central support
structure
according to the present invention, shown as being indefinite length.
Referring now to Figure 1 to 3, the basic collapsible insulation panel module
1 of
the present invention is illustrated. It comprises a pair of hinged together
lightweight rigid
insulating panels 2. The preferred material for the panels is rigid foam,
although other
appropriate materials, which will result in a rigid insulated wall, will be
obvious to one
skilled in the art. For instance, the panels may be fabricated as a thin box
with a
lightweight rigid frame, and upper and lower walls of stiff, lightweight
plastic
sandwiching a layer of fibreglass insulation.
Polyisocyuranate foam panels of between one and two inches in thickness are
used in a preferred embodiment of the present invention. Each panel will be
framed
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around its perimeter, and, at spaced intervals, with ribs extending between
the top and
bottom edges of the panels with a lightweight frame 3 of a rigid material such
as
aluminum, steel, extruded plastic, wood or the like. The function of the
framework is to
provide rigidity against bending forces which will be encountered during a
normal
operation as well as those which may accidentally he encountered, for instance
during
installation. Moreover, the perimeter frame will serve as a mounting surface
for hinges 4
that are provided at the lower edges of the panels, to hinge them either to a
centre support
wall/structure or together.
It will be understood, moreover, that references herein to the lower edge of
the
panels are for convenience, and reference to the illustrated embodiments of
Figures 1 to 6
only. It is entirely feasible to construct other embodiments of the invention
in such a way
that the panels are hinged to each other or to a centre support wall/structure
along their
upper longitudinal edges. If, for instance, one wished to have the default
position of the
panels to be folded into the centre, hanging them with the hinges along with
the top edge
may be appropriate. Furthermore, since it will be understood that the panels
may be
opened and closed by any means selected by one skilled in the art, it will be
understood
that in regard to some means of opening and closing, hanging the modules with
the
hinges along the top edge will be appropriate.
The outer surfaces of the panels 2 are preferably provided with a layer of
light
reflecting material 5. This may be, for instance, a layer of reflective
aluminum foil, or it
may be a coating of white paint. This reflective layer will maximise the light
directed
downwardly toward the plants being grown in the facility, and, if reflective
aluminum is
used, results in an increased insulation value for the insulated panels by
acting as a
radiant heat barrier.
The two panels 2 in each module are joined around their perimeter to each
other
by means firstly of the hinges 4 that extend along and join the lower edges of
the panels
to the lowermost edge of a supporting structure 12, a short section of which
is shown in
phantom in Figure 1, and by a series of flexible sheets that define a bellows
arrangement
around the remaining perimeter. The bellows consists of two congruent upper
flexible
membranes 6 that are rectangular. Each upper membrane is joined along its
lower edge 7
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to an upper edge of a panel 2, and along its upper edge 8 to the marginal edge
of a
longitudinally extending plenum 9, as shown in Figures 3, 6, and 7. Plenum 9
is mounted
at the top edge of a central support member 12, and consists of a
longitudinally extending
box-like structure connected at one or more points along its width to ducting
14. The
plenum 9 may be arched, rectangular, square, or any other desired shape, but
is preferably
substantially prism shaped, as shown in Figure 6, and the outer side surfaces
91 are either
coated with or constructed from light-reflective material such as light gauge
metal to
reflect light into the greenhouse. The lowermost pane192 of the plenum is a
horizontally
oriented wall with an air distribution channel 93 or channels formed in it. In
the
embodiment illustrated in Figure 7, air channe193 is a longitudinal slot, and
the lower
panel 92 is aligned with the top longitudinal edge 121 of a central support
structure 12.
Central support structure 12 is preferably a corrugated web 20 (see Fig. 8)
constructed
from steel, aluminum, fibreglass, or any other rigid material (the selection
of which will
be a matter of choice to one skilled in the art). The corrugations function to
strengthen the
structure 12, and also to distribute air entering the plenum evenly into both
sides of the
module. It will be understood, then, that all edges, connection to membrane 6,
and
connections between the plenum and central support will be airtight.
Moreover, it will be understood that central support 12, with plenum 9 and an
associated lower chord 41 which may be a C-shaped metal cap to which hinges 4
are
connected will effectively function as a truss structure, strengthening the
overall rigidity
of the greenhouse, and serving as a rigid member from which to hang the
modules in
place.
It will be further understood that although a corrugated central support
structure
12 has been described and illustrated as a preferred method of facilitating
even air
distribution, and therefore balanced opening and closing of the modules, other
means of
distributing air evenly, such as independent air ducts into each side of a
module, each
duct being provided with a pressure regulation valve, are possible. Moreover,
the
modules may be unevenly weighted, whereby the lighter weight panel will
consistently
be lifted first, resulting in consistent opening and closing characteristics.
Alternatively,
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the panels may be opened and closed mechanically, by wires or a rack and
pinion or a
pantograph or scissors arrangement.
Two alternate forms of central support structure 12 are shown in Figures 9 and
10.
In Figure 9, the central support structure is illustrated as an open framework
with top and
bottom frame members 23, spaced apart by end frame members 24, and braced by
corner
braces 21. The frame members 23, 24 and corner braces 21 are fabricated from
steel,
aluminum, fibreglass, carbon fibre or any other appropriate lightweight
material, as will
be a matter of choice to one skilled in the art.
In Figure 10, a central support structure that is designed to also function as
a truss
is shown. In this embodiment, the top and bottom frame members 23, as well as
the
plenum 9 and end frame member 24 are constructed from heavier gauge metal, so
as to
allow the plenum 9 to function as a chord in the truss, and effectively become
a structural
component in the greenhouse frame. A continuous series of diagonal braces 25
are
provided between the top and bottom frame members, to increase the rigidity of
the truss.
The edges of the panels 2 are joined together by end membrane 10 that each are
generally square or "diamond" shaped, and joined along their edges 101, 102,
103, 104 to
each pane12 and the end edges 11 of upper membrane 6. End membranes 10 are
formed
by folding the flexible membrane at the end of the membrane 6, and continuing
said
membrane along the end "wall" to result in the end "triangles". This end
triangle is then
sealed to the end of the centre wall structure/support and the end edge of the
insulated
panels, as shown in Figure 1, with each triangular piece being joined to the
vertical edge
of support structure 12. To ensure that the end membranes 10 are well sealed
to the ends
of support structure 12, a vertical trim piece may be applied over the
membrane 10,
along the end edge of support structure 12, and fastened thereto with screws,
rivets, or
other suitable fasteners.
It will be understood, moreover, that at all seams between flexible membranes
and
panels, an air-tight seal is formed, by the use of suitable adhesives and/or
sealants.
Furthermore, it will also be noted that the longitudinal hinge 4 between the
two panels
will also be air-tight. In this regard, a membrane (not shown) may be
adhesively applied,
or mechanically sealed, to the longitudinal joint between the panels along the
lower edge
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of support structure 12, either inside or outside the hinge 4. Alternatively,
the hinge may
be constructed from an air impermeable material such as strips of rubber
attached to the
lower edges of the insulated panels and support wall.
Referring now to Figure 3, it will be seen that a fan or blower 13, or other
air-flow 5 apparatus, is connected by means of plenum 9 or manifold above the
central support
structure 12. When air is evacuated from the module, it collapses to an open
position, as
shown in Figure 2. When the airflow evacuating the module is discontinued,
gravity
results in the insulated panels "falling" to their horizontally inclined
closed position,
drawing air back into the module during this process. At their closed,
inclined position,
the panels will preferably be supported by wires 15 (or cables, straps or the
like) inside
the modules (as shown in Figure 1, in phantom), extending from the central
support 12 to
the upper edge of the panel 3. The function of this wire 15 is to ensure that
the module
will consistently fall to the correct position, without stress being placed on
the plastic
material of the membranes.
As seen in Figures 4 and 5, a series of modules can be mounted in a building,
hung from the ceiling thereof. It will be understood that the modules must be
arranged in
parallel rows, and spaced apart such that, as shown in Figure 5, when the
modules are in
closed position, the edges of adjacent modules, as well as the contiguous ends
of the
modules which form the rows, will meet in a substantially air tight manner.
The air
tightness is substantially improved through the use of gasket seals. In this
regard, it
should be noted that it is not necessary for edge to edge contact of adjacent
modules, or
end to end contact of the panels forming a row, to be absolutely airtight. It
is desirable,
however, to prevent large airflows, and heat flows from the space below the
modules to
the space above the modules.
In their closed position, as shown in Figure 5, the lateral edges of the
module
define a continuous zig-zag shaped edge on each side of the modules.
Accordingly, it is
desirable that the building into which the modules are fitted be provided with
a
complementary perimeter margin, so that the lateral side edges of the panels
can also be
sealed, with respect to the walls of the building, against air and heat flow.
It will also be
understood that it is not necessary to provide a blower or fan 13 in
connection with each
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module. If a remotely located blower/fan air flow apparatus is provided, it
may be
connected by duct work to a plurality of modules, to open and close them in
groups.
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