Note: Descriptions are shown in the official language in which they were submitted.
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HEAT RESERVOIR
Cross Reference to Related Application
This application claims prioiity from United. States Provisional Patent
Application No. 61/004, 695 filed November 30, 2007 entitled Heat Reservoir.
Field of the Invention
This invention relates to heat reservoirs, and in particular heat reservoir
construction used in solar collection systems.
Background of the Invention
It is known that when making a heat reservoir primarily for use in solar
heating
applications that a supporting structure lined with a fluid impermeable
material may be a cost
effective method of construction. There are many instances of lined pressure
vessels, but few
instances of lined atmospheric pressure heat reservoirs.
In the prior art to applicant's knowledge applicant is aware of US patent
4,314,602 entitled "Knock-down Heat Storage Tank" which issued to Frederick,
et al. on
February 9th, 1982, and teaches a knock-down tank for containing a liquid
medium, the tank is
disassemblable rigid container having a bottom panel, an inner wall, separate
upright side-wall
panels with inner walls resting on the bottom panel and having abutting side,
and having a top
panel overlying the side-wall panels thus closing the container. The container
is snugly fitted
with a liquid-containing flexible liner having side walls fitting snuggly
within said side panels
and having a bottom wall supported by said bottom panel. The walls of the
liner lie against
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sheets of insulating material. A dip tube extends down into the liner through
a hole in the top
panel, thereby providing access to the liquid in the container.
Summa , of the Invention
The present i.nvention serves as a heat reservoir for liquids such as water
used
in heat transfer applications such as solar collection. The reservoir is cost
effective to
manufacture, consisting in one embodiment of'sheet metal wrapped and joined to
form an
open ended cylinder placed on an insulating base. The cylinder is lined with a
fluid tight
membrane on the inside such as EPDM roofing rubber sheet (or other flexible
flexible mater
tight sheet), and insulated on the outside. The lid is similarly constructed
with a vapor barrier
sheet of fluid tight membrane, a lid made of support material covered with
insulation. The
egress for the fluid circulation lines and the heat pump transfer lines is
through a section of the
upper rim of the cylindrical tank and the lid. The fluid tight membrane is a
sheet bonded into a
cylindrical section formed, prior to lifting with fluid, in the form of a
frusto-conical upper
portion and a wedge-shape lower portion. The bottom seam is reinforced by a
clamp to ensure
a water tight seal.
In summary, the non-pressurized fluid reservoir according to one aspect of the
present invention includes a housing shell defining a cavity, and a flexible
water impervious
bag-shaped liner mounted in the cavity so as to substantially fill the cavity
when the liner is
filled with fluid. The liner is formed from a flexible water-imperious sheet
by forming the
sheet into a cylinder, then forming a water-tight 6rst seain along a bottom
edge of the cylinder,
then folding outer corners of the first seam over, so as to overlap a center
portion of the first
seain, and so that bottom edges of the outer corners, once so folded over,
register substantially
co-linearly within a bottom edge of the center portion of the first seam. An
upper portion of
the liner is thereby urged to bag open. The upper portion thus fozms a
substantially
frustoconical shape. The upper portion is contiguous with a lower portion of
the liner. The
lower is portion substantially wedge shaped. The bottom corners overlapping
the center
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portion of the first seam are sealed onto the first seam so as to form a
second seal. The liner
may be resilient.
In one embodiment the sheet is formed into the cylinder by sealing opposite
ends of the sheet to one another along a third seam once the sheet has been
curled into a
cylindrical shape. The housing shell may also be substantially cylindrical,
and may be sized so
that the upper portion of the liner fits snugly inside the cavity of the
shell.
In use the lower portion of the liner folds under the upper portion of the
liner
when the liner is mounted in the cavity. When mounted in the cavity an upper
edge of the
liner registers with an upper rim of the housing shell. The rim extends around
an upper
opening into the cavity.
The lower portion of the liner folds under the upper portion to form a floor
surface of the liner and to flatten the floor surface of the liner down
against a substantially
horizontal supporting surface under said housing shell. In one einbodiment,
the housing shell
is open-bottomed, and the supporting surface is a separate insulated platform
surface, separate
from the shell. When fluid fills the liner in the cavity, the floor surface of
the liner spreads out
substantially to meet wall or walls of the shell.
In one embodiment, the upper edge of the liner is foldable or folded over to
form a lip. The rim of the housing shell may also further include a radially
spaced apart array
of liner-engaging protrusions to engage and lock to the folded-over lip.
The liner may further include a clamp. The clamp is clamped over said bottom
coiners and the center portion of the first seam when abutting together of
bottom corners over
the center portion of the first seam.
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Brief Description of the Drawings
In the accompanying figures wherein similar characters of reference denote
corresponding parts in each view:
Figure I is, in front elevation view, the assembled heat reservoir of the
present
invention.
Figure 1 a is a side cutaway view along line 1 A - lA in Figure 1.
Figure 2 is, in front perspective exploded view, the heat reservoir of Figure
1.
Figure 3 is, in enlarged front perspective view, the formed sheet metal
cylinder
of Figure 2.
Figure 3a is, in enlarged partially-cutaway front perspective detail view, a
portion of the sheet metal cylinder of Figure 3.
Figure 4 is, in front perspective view, the sheet metal cylinder of Figure 2,
reinforced with iron.
Figure 4a is, in enlarged partially cutaway front perspective detail view, a
portion of the metal cylinder of Figure 4.
Figure 5a is, in perspective view, the fluid tight membrane liner sheet when
curled into a cylinder, showing first stage of the formation of the liner
during which the
vertical seam of the liner is formed.
Figure 5b is in perspective view, the liner of Figure 5a with the vertical
seam
formed to close the cylinder and the lower end of the cylinder closed along a
bottom linear
seam.
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Figure 5c is, in perspective view, the liner of Figure 5b with the lower
corners
folded to the center to abut together along the center portion of the bottom
linear seam.
Figure 6 is, in elevated view, the fluid tight membrane liner sheet of Figure
5c
with the lower corners folded into place on the bottom linear seam.
Figure 7 is, in plan detailed view, the lower portion of the fluid tight
membrane
liner sheet of Figure 6 with a double angle iron clamp applied to secure
corners of the liner
bottom seam.
Figure 7a is, an edge view along line 7a - 7a in Figure 7
Figure 8 is, in perspective view, the double angle iron clamp of Figure 7.
Figure 9 is, in plan view, an alternative embodiinent of tlie heat reservoir
housing shell of the heat reservoir of the present invention wherein the
housing is formed as an
open top and open bottom rectangular box made of two formed sheets of metal
fastened
together.
Figure 10 is, in front perspective view, one half of the rectangular reservoir
housing of figure 9 in its assembled form showing the rib locations,
insulation locations,
flanges, and flange bolt holes.
Figure 11 is, in plan view, the ribs of the rectangular reservoir housing of
Figure 1Ø
Figure 12 is, in plan view, the heat reservoir housing shell of Figure 10
completed and prior to installing the fluid tight liner.
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Detailed Description of Embodiments of the Invention
Heat reservoir 1 provides a holding tank for liquid to be stored in liquid
holding
cavity 8. The holding tank is for use in non-pressurized liquid storage
applications, most
typically as a heat reservoir for solar heating applications.
The supporting structure of reservoir I is constructed of sheet metal. In the
embodiments of Figures 1 - 8, the sheet metal is rolled into a cylinder 5.
Flanges 9 are formed
along the mating edges of the rolled sheet. Lengths of angle iron 15 are
positioned along the
outer surfaces of abutting flanges 9. Bolts 16 are journalled through
apertures in both angle
iron 15 and flanges 9 to create a structurally sound seam along flanges 9,
thereby securing the
sheet as an open ended cylinder 5.
The cylinder 5 is placed onto an insulating base 2 such as Styrofoam TM or
other
insulating structural material, and then wrapped in an insulating blanket 3 of
fiberglass or
styrofoam or other insulators. The insulation may be covered on its outside
with metallic foil
such as aluininum foil or other covers.
Screws 17 or other fastening means are inserted through apertures formed
around the upper rim of the open cylinder 5. Screws 17 are screwed through the
sheet metal of
cylinder 5 from the inside of the cylinder outward, thus leaving sharp ended
protrusions that
may serve as liner anchors.
The liner is forined by folding and clamping sheets of fluid tight membrane.
The membrane is flexible, and is advantageously also resilient. For example,
two sheets may
be bonded together using adhesive along seam 11 to form a long rectangular
sheet which may
be then rolled into a cylinder of approximately the same diameter as cylinder
5. The free ends
of the rolled rectangular sheet are overlapped aiid bonded along a further
vertical seam I 1 to
form a cylinder. The edge 23 of the fluid tight membrane sheet 6 cylinder
selected to be the
bottom of the tank or reservoir liner is similarly bonded into a seam 18 by
coating the inside
surface of the lower edge of the cylinder with an adhesive or other bonding
agent and
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clalnping those inside surfaces together. This forins a cylindrical bag liner
that is open at its
upper end. The corners 18a of the resulting straight edged seam 18 are then
folded in direction
B to bring the corners in towards the axis A (shown to be parallel to seam 11)
Folding in
corners 18a to abut together over the center portion 18b forms a substantially
wedge-shaped
lower portion of the liner bag. Once folded in direction B the corners 18a are
pulled down in
direction C such that the bottom edge of the folded corners 18a and the bottom
edge of the
center portion 18b of linear seam 18 are substantially collinear.
Pulling corners 18a down in direction C so as to overlay the corners on the
center portion 18b of the bottom linear seain 18 causes the upper rim 6a of
the bag liner to
opcn in direction D, thereby assisting in forming the open shape of the liner.
Initially the
shape of the liner is frustoconical in the upper portion and wedge-shaped
towards the bottom
so as to narrow down to linear seam 18. The pre-forming of the liner helps
ease installation of
the liner in the housing shell, and provides an. inexpensive sealed liner for
use in non-pressure,
i.e. un-regulated vessels.
The seam 24 comprising the overlapped corners 18a overlapped along the
center portion I8b of seam 18 is then clamped using a clamping means 20 such
as angle iron
21 and fasteners 22. The corners 18a of bottoin seain 18 are clamped over and
onto center
portion 18b so as to maintain the integrity of the seam corners 18a and
thereby prevent leakage
once the bag liner is installed in the housing shell and filled with liquid.
Once the seams have
been established and secured the bag liner is lowered into the open end of the
cylindrical
housing shell, and the upper edge of the bag line:r is folded to form lip 12
over the upper rim of
the cylinder. Lip 12 is impaled onto the outwardly pointing fasteners 17,
thereby securing the
bag liner to the sheet metal cylinder 5, forming fluid tight tank or reseivoir
1. As the liner is
lowered into the cavity 8 the lower wedge-shaped portion of the liner folds
under the upper
portion as the lower portion contacts the base 2. This forms the floor of the
liner. As fluid
fills the liner, the upper portion of the liner confirms to the interior of
the cavity.
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Ports are cut in the walls of the cylindrical reservoir I at various locations
and
elevations as necessary to plumb in inlet and outlet tubes both for the
reservoir fluid and for
any heat exchanger and instrumentation placed into the reservoir. Fluid tight
seals are fonned
around the tubes and instrumentation cabling to maintain the fluid tight
integrity of the
reseivoir. Cavity 8 in reservoir 1 is filled with heat exchange fluid such as
water.
A second fluid tight membrane sheet 7 is cut in a circle of diameter larger
than
the diameter of the upper rim of cylinder 5. Sheet 7 is cut with sufficient
excess material so
that the circumferential edge may be folded downward also impaled onto the
outwardly
pointing ends of fasteners 17, thus sheet 7 may be affixed over the reservoir
opening by being
attached to the outwardly proti-izding fasteners 17. A structurally supporting
member such as
sheet metal, wood, chloroplast board or other is cut to the fit the top of the
reservoir, and is
fitted along with a covering of insulation 4 and weatherproof material such as
metalized paper
like aluminum foil or similar. All insulation seams and interfaces are sealed
with seam tape or
other sealants to reduce the likelihood of heat loss.
Instrumentation such as temperature and flow sensors may also be installed in
the reservoir for monitoring and control.
Figures 9 - 12 illustrate an alternative embodiment of the present invention
which may be constructed by forniing two metal sheets 27 into half profiles of
an open top and
bottom rectangular box as. Each sheet 27 is folded to form the corners of the
bisected open
top and bottom rectangular box. Flanges 9' are formed at the interfacing edges
of the sheets
where the sheets match up to form the open top and bottom rectangular box. The
two sheets
27 are assembled on an insulating base 2' with each of the two flanges 9'
mating with those of
the opposite sheet 27. Angle iron backing 15' bolsters eacli flange 9'. Each
Flange 9' is
sandwiched between two pieces of angle iron 15'. Bolts fasten the made iron
onto the flanges.
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Ribs 28 and 29 are profiled in an are like fashion. Ribs 28 and 2a are mounted
in vertically spaced apart aray elevations along the height of the walls of
the rectangular
reservoir 26. The flat sides of the ribs mate with the inside surface of the
metal sheet 27. Ribs
28 and 29 may be frictionally secured in place by a tolerance fit between
opposing walls of the
open top and bottom rectangular box. The ribs 28 and 29 are installed in sets
of four, that is, on
the same elevation one rib will be mounted on each end and on each side such
that two
adjacent rib ends have an i.nterference fit with corner brace 33 mounted in
the corners of the
rectangular reservoir 26. The number of ribs sets required depends on the
height of the
rectangular reservoir 26. Ribs are shown at three elevations by way of
example. Insulation 30,
which may be spray-on polyurethane, or other foam insulation material, is
placed between the
ribs. Insulation is also placed between the upper and lower most ribs and the
edge of the open-
ended rectangular box. Additional insulation 31 placed in the corners. After
installing a
number of rib sets 28 and 29 at various elevations, sheets of material 32 are
fonned and
fastened by stapling or other means to the curved surfaces of the ribs 28 and
29 secured to each
inside face of the rectangular open top and bottom box, and fitted with an
interference fit with
the sheet 32 of the adjacent face where they meet: in the corners.
A fluid tight liner 6, as described above is placed into the open ended
rectangular box 26 and fastened to the rim by liner anchors 10 similar to that
used for
cylindrical reservoir 1. Ports are cut into the walls at various locations and
elevations to
plumb in the inlet and outlet tubes both for the reservoir fluid and for any
heat exchanger and
instrumentation placed into the reservoir, and then fluid tight seals are
formed around the tubes
and instrumentation cabling to maintain the fluid tight integrity of the
reservoir.
The cavity in reservoir 26 is filled with heat exchange fluid such as water. A
second fluid tight membrane sheet 7 generally cut in a rectangular manner,
larger than the
opening or the rectangular box 26 with enough excess to be s'vnilarly impaled
onto the
outwardly pointing fasteners 17, and is placed over the reservoir opening and
attached to the
outwardly protruding fasteners 17. A structurally supporting member such as
sheet metal,
wood, chloroplast board or other is cut to the fit the top of the reservoir,
and is fitted along
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with a covering of insulation 4 and weatherproof material such as metalized
paper like
aluminum foil or similar. All insulation seams and interfaces are sealed with
seam tape or
other sealants to reduce the likelihood of heat loss.
As will be apparent to those skilled in the art in the light of the foregoing
disclosure, many alterations and modifications are possible in the practice of
this invention
without depat-ting from the spirit or scope thereof.
