U.S. patent application number 09/982694 was filed with the patent office on 2002-02-28 for pool cover.
Invention is credited to Bussey, Harry JR., Ellison, Edward J..
Application Number | 20020023296 09/982694 |
Document ID | / |
Family ID | 24628966 |
Filed Date | 2002-02-28 |
United States Patent
Application |
20020023296 |
Kind Code |
A1 |
Bussey, Harry JR. ; et
al. |
February 28, 2002 |
Pool cover
Abstract
The pool cover is made of multi-layer light-weight construction
having a translucent top layer to permit sunlight to pass through
and an opaque bottom layer for absorbing sunlight passing through
the translucent layer. In a two-layer construction, a plurality of
pockets are formed in the bottom layer. In a three-layer
construction, a plurality of pockets are formed in the intermediate
layer. When in use, the opaque layer becomes heated by sunlight and
transfers heat by contact to the water in the pool. The heated air
in the pockets also serves to conduct heat to the water and to
serve as a thermal insulating barrier during non-daylight hours.
The top layer may also be made of reflective material to reduce
heating of the water during short-term pool closures.
Inventors: |
Bussey, Harry JR.; (Marco
Island, FL) ; Ellison, Edward J.; (Oakland,
NJ) |
Correspondence
Address: |
CLAIRE ANN KOEGLER
SUITE 301
447 NORTHFIELD AVENUE
WEST ORANGE
NJ
07052
US
|
Family ID: |
24628966 |
Appl. No.: |
09/982694 |
Filed: |
October 18, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09982694 |
Oct 18, 2001 |
|
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|
09655458 |
Sep 5, 2000 |
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Current U.S.
Class: |
4/498 |
Current CPC
Class: |
E04H 4/10 20130101; Y02E
10/44 20130101; F24S 10/17 20180501 |
Class at
Publication: |
4/498 |
International
Class: |
E04H 004/00 |
Claims
What is claimed is:
1. A pool cover comprising a first flat upper translucent layer for
passing sunlight therethrough; a second intermediate layer secured
to said first layer, said second layer having a plurality of
pockets therein facing said first layer sealed relative to said
first layer to encapsulate air therein to form an insulating
barrier over a pool surface; and a third underlying opaque layer
secured to said second layer to encapsulate air therebetween to
provide further insulation, to reduce evaporation from the pool
surface, and to inhibit growth of algae.
2. A pool cover as set forth in claim 1 wherein each layer is made
of plastic and is flexible to permit folding or rolling of the pool
cover.
3. A pool cover as set forth in claim 1 in which said three layers
are coextensive and wherein said layers are sealed together at the
peripheral edges thereof.
4. A pool cover as set forth in claim 1 in which said layers are
coextensive and oversized relative to the pool surface whereby when
installed on a pool surface, the peripheral edges thereof extend
upwards along the sides of the pool.
5. A pool cover as set forth in claim 1 further comprising a
plurality of drainage holes in said layers for passing water
therethrough, wherein said plural drainage holes are provided
through selected ones of said pockets.
6. A pool cover as set forth in claim 1 wherein at least one of
said upper layer and said intermediate layer is transparent.
7. A pool cover comprising a first flat upper reflective layer for
reflecting external heat away from a pool surface; a second
intermediate layer secured to said first layer, said second layer
having a plurality of pockets therein facing said first layer
sealed relative to said first layer to encapsulate air therein to
form an insulating barrier over a pool surface; and a third
underlying opaque layer secured to said second layer to encapsulate
air therebetween to provide further insulation, to reduce
evaporation from the pool surface, and to inhibit growth of
algae.
8. A pool cover as set forth in claim 7 wherein each layer is made
of plastic and is flexible to permit folding or rolling of the pool
cover.
9. A pool cover as set forth in claim 7 in which said three layers
are coextensive and wherein said layers are sealed together at the
peripheral edges thereof.
10. A pool cover as set forth in claim 7 in which said layers are
coextensive and oversized relative to the pool surface whereby when
installed on a pool surface, the peripheral edges thereof extend
upwards along the sides of the pool.
11. A pool cover as set forth in claim 7 further comprising a
plurality of drainage holes in said layers for passing water
therethrough, wherein said plural drainage holes are provided
through selected ones of said pockets.
12. A pool cover as set forth in claim 7 wherein said first upper
layer is provided with a reflective coating on the top surface
thereof to make said layer reflective.
13. A pool cover as set forth in claim 7 in which metallic powder
is distributed through said first upper layer to make said layer
reflective.
14. A pool cover comprising a first underlying opaque layer to
inhibit growth of algae and to reduce evaporation from a pool
surface; a second intermediate layer secured to said first layer,
said second layer having a plurality of pockets therein facing said
first layer sealed relative to said first layer to encapsulate air
therein to form an insulating barrier over a pool surface; and a
third flat overlying translucent for passing sunlight therethrough
secured to said second layer to encapsulate air therebetween to
provide further insulation.
15. A pool cover as set forth in claim 14 wherein each layer is
made of plastic and is flexible to permit folding or rolling of the
pool cover.
16. A pool cover as set forth in claim 14 in which said three
layers are coextensive and wherein said layers are sealed together
at the peripheral edges thereof.
17. A pool cover as set forth in claim 14 in which said layers are
coextensive and oversized relative to the pool surface whereby when
installed on a pool surface, the peripheral edges thereof extend
upwards along the sides of the pool.
18. A pool cover as set forth in claim 14 further comprising a
plurality of drainage holes in said layers for passing water
therethrough, wherein said plural drainage holes are provided
through selected ones of said pockets.
19. A pool cover as set forth in claim 14 wherein at least one of
said overlying layer and said intermediate layer is
transparent.
20. A pool cover comprising a first underlying opaque layer to
inhibit growth of algae and to reduce evaporation from a pool
surface; a second intermediate layer secured to said first layer,
said second layer having a plurality of pockets therein facing said
first layer sealed relative to said first layer to encapsulate air
therein to form an insulating barrier over a pool surface; and a
third flat overlying reflective layer secured to said second layer
to encapsulate air therebetween to provide further insulation and
to reflect external heat away from the pool surface.
21. A pool cover as set forth in claim 20 wherein each layer is
made of plastic and is flexible to permit folding or rolling of the
pool cover.
22. A pool cover as set forth in claim 20 in which said three
layers are coextensive and wherein said layers are sealed together
at the peripheral edges thereof.
23. A pool cover as set forth in claim 20 in which said layers are
coextensive and oversized relative to the pool surface whereby when
installed on a pool surface, the peripheral edges thereof extend
upwards along the sides of the pool.
24. A pool cover as set forth in claim 20 further comprising a
plurality of drainage holes in said layers for passing water
therethrough, wherein said plural drainage holes are provided
through selected ones of said pockets.
25. A pool cover as set forth in claim 20 wherein said first upper
layer is provided with a reflective coating on the top surface
thereof to make said layer reflective.
26. A pool cover as set forth in claim 20 in which metallic powder
is distributed through said first upper layer to make said layer
reflective.
Description
BACKGROUND OF THE INVENTION
[0001] This application is a continuation-in-part of copending
application Ser. No. 08/180,423, filed Jan. 12, 1994. The
applicants herein are also the inventors of U.S. Pat. No.
5,511,536, issued Apr. 30, 1996, for SOLAR-TYPE POOL COVER.
[0002] This invention relates to pool covers, and, in particular,
solar pool covers. More specifically, this invention relates to
pool covers useful for temporary or short-term closures of
pools.
[0003] As is known, various types of pool covers have been employed
for covering over swimming pools and the like. In some cases, a
tarpaulin-like cover has been employed to cover over a swimming
pool when the pool is not in use in order to prevent dirt and
debris from falling into the water contained within the pool.
Typically, these covers are of relatively light weight construction
allowing fine-sized debris to enter the pool.
[0004] Other covers have been designed to close a pool for the
season. This type of cover is placed over the entire pool including
a small area around the perimeter to allow the placement of
weighting means to hold the cover and place and to seal the
perimeter to prevent dirt and debris from entering the pool. This
type of cover is usually waterproof and collects rain water as well
as debris on the top surface thereof, making removal of the cover
difficult.
[0005] In cases where a swimming pool is heated, use has been made
of covers which are constructed to retain as much heat as possible
within the body of water within the pool. For example, some pool
covers have used a combination of glass and aluminum in an attempt
to conserve heat within the pool. However, the use of such
materials can be dangerous while being difficult to handle. For
example, there is a potential danger of glass breakage while the
incompatibility of chlorine with aluminum dictates against the use
of such a cover for swimming pool applications.
[0006] Other types of pool covers have been of a solar type. For
example, U.S. Pat. No. 3,022,781 describes a heater made of plastic
film layers wherein a lower layer is made absorbent to radiant
energy by being painted black or by incorporating a black pigment
within the plastic composition.
[0007] U.S. Pat. No. 3,072,920 (Yellott) describes a swimming pool
cover for collection or reflection of solar heat in which the cover
is made of a sheet of plastic material having a bottom surface
covered with a layer of dark-colored material for the absorption of
solar energy and an upper surface covered by a reflective surface,
such as aluminum. In addition, an over-layer of transparent plastic
material is attached to the marginal edge of the plastic sheet to
form air-filled compartments or pockets to increase the buoyancy of
the cover. In the summer, the cover is to be turned so that the
dark absorptive surface is down facing the water with the
aluminized surface facing the sky to reflect the sun's radiant
energy. In the winter, the cover is to be reversed so that the dark
surface is exposed to solar energy.
[0008] U.S. Pat. No. 3,893,443 (Smith) describes a floating pool
heater comprising plural individual units, each capable of floating
and having a bottom wall with a blackened surface on the inside.
The units are rigid, being made of metal, fiberglass, or reinforced
plastic resin.
[0009] U.S. Pat. No. 3,949,095 (Pelehach) describes a solar pool
heating apparatus comprising plural individual units, each capable
of floating and having a reflective bottom surface and transparent
top surface.
[0010] U.S. Pat. No. 4,028,750 (Gustafsson) describes a pool cover
having plural buoyancy cells, drainage apertures between the cells,
and rigid reinforcing elements.
[0011] U.S. Pat. No. 4,146,015 (Acker) describes a solar pool
heater which employs a membrane having a smooth side and a pebbled
side wherein each of the pebbles is a sealed air pocket. The entire
membrane is transparent to permit the transmission of radiant
energy to heat the underlying water and pool bottom.
[0012] U.S. Pat. No. 4,426,995 (Wilson) describes a solar quilt
intended primarily for agricultural purposes, although the use as a
pool cover is mentioned. The quilt is described as having an upper
film formed of semi-hemispherical modules which abut and are sealed
to a lower film which is described as transmissive of downwardly
directed solar radiation and reflective of upwardly directed
radiant energy in the ultra-violet range. The lower film is said to
be absorptive of incident solar energy. The lower layer is
optionally made opaque through the use of metals or metal oxides
applied to the surface of or throughout the layer. Metals and metal
oxides would be inappropriate for use in a pool cover, since they
are incompatible with chlorine. Wilson also recommends the use of
strengthening materials or compartments running the length of the
quilt. The construction of such a quilt, if placed on a pool, would
permit free air flow under and through the quilt, which would cool
the water as well as allowing entry of dirt and debris.
[0013] U.S. Pat. No. 4,709,688 (Paradis) describes an open cell
pool cover intended for use with a water circulation system to
allow flow of water through the pool cover. When the water
circulation system is not in use, air would flow through these open
cells which would cool the water as well as allowing entry of dirt
and debris. Reference is made to previously known sealed cell pool
covers which include an upper plastic sheet with dimples and a
plastic sheet bonded to the upper sheet. Such a sheet would collect
water, dirt, and debris on the top surface thereof.
[0014] Generally, the previously known structures are of relatively
thick, heavy-weight construction. In those cases in which the
covers which have been made of lightweight materials, the covers
have tended to be of a transparent nature such that heat energy in
a covered pool is permitted to radiate out of the pool through the
cover during dark periods. Also, where the covers have been
transparent, a portion of the radiant energy is reflected without
being converted to heat to heat the pool water. Those covers which
attempted to heat the water used a greenhouse effect, which
promoted algae growth in and on the pool surfaces due to the
passage of light into the water below the cover.
[0015] It has been known that a translucent or transparent cover
will help heat a pool but that it also promotes algae growth and
increases chemical usage to a point of danger to the user. While
the pool cover of the present invention can be used to heat the
pool, it does not employ a greenhouse effect. Moreover, it reduces
algae growth and chemical usage.
[0016] The cover of the present invention forms an insulating
barrier during periods of darkness, such as nighttime hours or cool
day conditions, in order to conserve heat within a heated body of
water within a swimming pool. This is accomplished in two ways.
First, during sunlight hours, the heat rays of the sun impinging on
the translucent or transparent top layer pass through and strike
the bottom opaque layer and are converted to heat. The pool water
then absorbs the heat either by contact with the opaque layer or
through conduction from the super hot air trapped in the air
pockets. Second, the pool cover serves to eliminate evaporation
from the pool water while the cover is in place on the pool
surface.
[0017] In another embodiment of the present invention for short
term pool closures, the top layer is made reflective to prevent
overheating of the pool and to further suppress algae growth.
[0018] During daylight hours, the opaque bottom layer of the pool
cover blocks the light which is necessary for algae growth. Coupled
with the evaporation preventing characteristics of the pool cover,
the need for pool chemicals and water replacement is greatly
diminished.
[0019] Accordingly, it is an object of the invention to provide a
pool cover which has good insulating qualities with enhanced heat
transfer into a body of water in a pool.
[0020] It is another object of the invention to provide a pool
cover which is of lightweight construction and which can be easily
handled.
[0021] Another object of the invention is to reduce or eliminate
water evaporation.
[0022] It is yet another object of the invention to provide a pool
cover which has an efficient heat transfer quality.
[0023] It is another object of the invention to provide a pool
cover which eliminates algae growth while the cover is on a
swimming pool.
[0024] It is yet another object of the invention to reduce the need
for chemicals in maintaining a swimming pool.
[0025] It is still another object of the invention to provide a
pool cover which can be made of recycled plastic materials.
[0026] It is still another object of the invention to provide a
pool cover of low cost construction.
[0027] It is a further object of the invention to provide less
filter run time with corresponding reduced pump run time which in
turn reduces the amount of electric power needed.
[0028] It is a still further object of the invention to prevent
dirt and debris from entering the pool water, both directly and
during removal of the pool cover.
[0029] Yet another object of the invention is to provide a pool
cover for short-term closure to keep a pool clean and easily
restored to service.
[0030] Yet a further object of the invention is to eliminate filter
run time and/or pump run time during a short-term closure of a pool
and/or to eliminate the use of electricity during such closure.
[0031] Still a further object of the invention is to eliminate the
need for chemicals during a short-term closure of a pool.
[0032] Still another object of the invention is to eliminate the
need to drain and refill a pool for a short-term closure
thereof.
[0033] Still another object of the invention is to keep the pool
water cool during short term closures.
[0034] Yet another object of the invention is to reduce or
eliminate the cost of pool maintenance during short term
closures.
[0035] These and other objects and advantages of the invention will
become more apparent from the detailed description taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is a top view of a pool cover in accordance with the
invention, in which the pool cover is disposed over a pool.
[0037] FIG. 2A is a cross-sectional view of a two-layer pool cover
in accordance with the invention, in which the pool cover is
floating on a body of water within a pool.
[0038] FIG. 2B is an enlarged view of a portion of a cross-section
of a two-layer pool cover showing one row of encapsulated air
pockets and the air pockets trapped between the pool cover and the
water.
[0039] FIG. 2C is an enlarged view of a portion of a cross-section
of a two-layer pool cover showing a first row of encapsulated air
pockets and a second staggered row of encapsulated air pockets.
[0040] FIG. 3A is a cross-sectional view of a three-layer pool
cover in accordance with the invention, in which the air pockets in
the middle layer point towards the bottom layer.
[0041] FIG. 3B is an enlarged view of a portion of a three-layer
pool cover showing one row of encapsulated air pockets and the air
pockets trapped between the middle layer and the bottom layer.
[0042] FIG. 3C is an enlarged view of a portion of a three-layer
pool cover showing a first row of encapsulated air pockets and a
second staggered row of encapsulated air pockets.
[0043] FIG. 4 is an enlarged view of a portion of a three-layer
pool cover in accordance with the invention, in which the air
pockets in the middle layer point towards the top layer, and
showing one row of encapsulated air pockets and the air pockets
trapped between the middle layer and the top layer.
[0044] FIG. 5 is a cross-sectional view of an oversized three-layer
pool cover in accordance with the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0045] As shown in FIG. 1, a pool cover 10 is of rectangular shape
(or shaped to fit the pool configuration) and is disposed in
floating relation on a body of water (12 in FIGS. 2A-2C) within a
pool 11. The pool cover may be of other shapes than rectangular and
may be custom-shaped to the shape of a given pool. The cover is
flexible and may be folded for storage when not in use.
Alternately, a means 13 is positioned adjacent the pool 11 for
winding of the pool cover 10 thereon when the cover is not in use.
The description and function of the means 13 is set forth in detail
in the specification and the drawings of application Ser. No.
08/180,423, filed Jan. 12, 1994, which disclosure is hereby
incorporated by reference as if fully set forth herein.
[0046] In an embodiment shown in FIG. 2A, the pool cover 10 is of
flexible construction and is made of two layers 14, 15. The
construction of the pool cover is such that each layer may be made
of a suitable lightweight plastic material, including without
limitation polyvinylchloride, polystyrene, polyethylene,
polypropylene. In addition, the overall pool cover is flexible so
as to permit rolling up on itself or folding.
[0047] As shown in FIG. 2A and in enlargement in FIG. 2B, the pool
cover 10 includes a first top layer 14 and a second bottom layer 15
secured to the first layer 14 in any suitable fashion, such as by
bonding or the like, and preferably by heat welding. At least one
of the layers (the bottom layer 15 in FIGS. 2A and 2B) has a
plurality of pockets therein facing the other layer (the top layer
14 in FIGS. 2A and 2B) and which pockets are sealed relative to the
other layer to encapsulate air therein.
[0048] In accordance with an embodiment of the invention, the top
layer 14 comprises a translucent, or preferably transparent, layer
for passing sunlight therethrough. The translucent or transparent
layer 14 is of planar shape and is of a thickness of, for example,
from about 1 to about 20 mils, preferably from about 1 to about 10
mils, and most preferably from about 1 to about 5 mils. The second
layer 15 is opaque for absorbing sunlight passing through the
translucent or transparent layer 14. The second opaque layer 15 is
coextensive with the first layer 14, and of a thickness of, for
example, from about 1 to about 20 mils, preferably from about 1 to
about 10 mils, and most preferably from about 1 to about 5 mils.
The choice of thicknesses is dictated by the desire for flexibility
versus the desire for standing up to wear and tear. This compromise
is best achieved by making the top translucent layer as thin as
desirable and the bottom opaque layer somewhat thicker to handle
the wear and tear during installation and removal and storage.
Thus, for example, the top layer may desirably be 1 to 2 mils thick
and the bottom layer may desirably be 2 to 4 mils thick. The cover
10 may be made of recycled plastic material, which is less costly.
The opaque layer 15 may be made black in color, although any other
dark color may be used. Thus, as illustrated in FIGS. 2A and 2B, it
is the opaque layer 15 which has a plurality of pockets 16 formed
therein in facing relation to the translucent or transparent layer
14. These pockets 16 are sealed relative to the translucent or
transparent layer 14 so as to encapsulate air therein.
[0049] The pockets 16 may be of any shape, although semispherical
or semiellipsoid or other shapes without corners are generally
preferred. The pockets 16 may be of a variety of sizes to
accomodate flexibility, handling, shipping, and storage
requirements, but preferably the pockets 16 are at least 1/8 inch
to an inch or more in diameter and at least 1/8 inch to a half inch
or more in depth. The size, and particularly the depth, of the
pockets is a factor to be considered in determining the thickness
of the layer. Larger, and particularly deeper, pockets will require
a greater thickness. As shown in FIG. 2C, the rows of pockets 16,
16a are arranged in staggered fashion to permit trapping of air in
the spaces 17 between the pockets 16 between the bottom layer 15
and the surface of the water 12. Preferably the diameter of the
pockets is greater than the spacing between the pockets to provide
greater contact with the water 12 in the pool.
[0050] The construction described is such that sunlight passing
through the translucent or transparent layer heats the opaque layer
15 and the air in the pockets 16 and the opaque layer 15 conducts
the heat to the pool water 12 under the opaque layer. The air
sealed in the pockets 16 forms an insulating barrier for heat
attempting to escape up through the cover 10, while the opaque
layer 15 eliminates, or greatly reduces, the evaporation from the
surface of the water 12 in the pool 11.
[0051] As shown in FIGS. 2A-2C, the encapsulated air pockets 16 are
partially submerged in the water 12, so that additional air pockets
17 are formed between the bottom surfaces of the opaque layer 15
between the pockets 16 and the surface of the water 12. Again, it
is noted that the rows of pockets 16, 16a are in staggered
relation, as shown in FIG. 2C, so as to create staggered pockets
17.
[0052] The pool cover 10 may be made in any suitable fashion. For
example, a planar sheet of opaque material may be passed over a
roller which has recesses therein, so that the pockets can be
formed by being drawn into the recesses. Alternatively, the sheet
of opaque material may be passed over a roller provided with
projections of semi-spherical shape, for example, which serve to
deform the sheet to form the pockets. Thereafter, a translucent or
transparent layer and the formed opaque layer can be brought into
mutual contact and sealed relative to each other so as to entrap
air within the pockets 16. The resulting multi-layered sheet can
then be cut into suitable widths, lengths, shapes, or desired
configuration for the formation of the pool cover 10. A pool cover
10 may be made of one continuous piece or of multiple sections
secured together in any suitable manner. Typically, in the
manufacturing process, the lengthwise edges are flat (without
pockets) for the outer 1/2 to 1 inch thereof. Thus, two sections
may be joined by overlapping the flat lengthwise edges thereof and
heat welding them together.
[0053] Since the pool cover 10 is of relatively light weight and
flexible construction and because of the size and spacing of the
pockets 16 in the opaque layer 15, when the cover 10 is rolled or
folded, the pockets 16 retain their shape without collapsing.
Further, since the cover 10 is made of plastic material having a
planar upper surface, a minimum amount of water is retained on the
cover 10 so as not to impede the folding or rolling of the cover
10.
[0054] When in use, the pool cover 10 is laid over the body of
water 12 within the pool 11 during cool periods or during nighttime
periods in order to conserve heat within the body of water 12. The
pool 11 may optionally be of heated construction so that the water
12 can be heated to suitable temperatures for recreational or
therapeutic purposes.
[0055] During daytime, sunlight which impinges on the pool cover 10
passes through the translucent or transparent layer 14 to heat the
opaque layer 15, which in turn serves to transfer the heat to. the
body of water 12 either by direct contact or through the heated air
pockets 16 and 17. The pool 11 is optionally provided with
recirculation equipment so that the hotter water at the top of the
pool can be cycled to the bottom of the pool whereby the cooler
water at the bottom of the pool rises to the top to be heated
through use of the cover 10.
[0056] At the same time as the opaque layer 15 is being heated by
sunlight, the air encapsulated within the pockets 16 and trapped in
the pockets 17 is also heated, providing additional heat transfer
to the water 12. During non-daylight hours, the encapsulated air in
pockets 16 and trapped air in pockets 17 acts as a thermal barrier
to the passage of heat upwardly through the cover 10. Thus, the
heat from the opaque layer 15 and the body of water 12 is retarded
from passing upwardly through the pool cover 10.
[0057] Since the opaque layer 15 serves to block passage of
sunlight into the body of water 12, algae growth is inhibited in
the water 12 and on the sides of the pool 11. This, in turn, leads
to a reduction in the need for chemicals in the water 12 to
suppress algae growth. Further, since the layer is opaque, there is
no need to incorporate an ultraviolet light inhibitor in the
plastic material of the layer.
[0058] Thus, the invention provides a pool cover 10 of relatively
light weight, which can be readily wound up on itself or folded for
storage purposes when not in use. The invention further provides a
pool cover which can be readily manufactured and installed.
[0059] By way of example, a pool cover constructed as shown in
FIGS. 2A-2C was compared with a conventional translucent
aqua-colored bubble cover of known construction. Two four-foot
round pools, each approximately one foot deep and equipped with a
recirculating pump, were used for the comparison. A pool cover in
accordance with FIGS. 2A-2C was placed over one pool (pool A) and
the second pool (pool B) was covered with a conventional bubble
cover. Both pools were subjected to the same sun and wind
conditions.
[0060] The results obtained show that the new pool cover on pool A
absorbed more heat than the conventional pool cover on pool B.
Specifically, the water in pool A was found to be consistently 4
degrees F. warmer than the water in pool B. Moreover, the opaque
layer in the test, which was black, inhibited the growth of algae
compared to the conventional pool cover. And, the use of recycled
materials reduced the cost of manufacture, while reducing
pollutants.
[0061] A second experiment was conducted on algae growth using an
18-foot by 36-foot, deep hopper in-ground vinyl-lined pool. The
chlorine, measured in parts per million (ppm), was allowed to drop
to 0.2 ppm, and the temperature was raised to 90 degrees F. After
forty (40) hours under these conditions, algae began to form on the
vinyl liner of the pool. A pool cover in accordance with FIGS.
2A-2C (having a black opaque layer) was then placed on the entire
water surface for forty-eight (48) hours. When the cover was
removed, the algae that had been on the vinyl liner was no longer
visible.
[0062] Thus, the invention provides a pool cover which greatly
reduces the need for chlorine and algaecides, which in turn reduces
the amount of pollutants released into the environment.
[0063] Still further, the use of the cover reduces the need for
pump run time thereby saving electricity and increasing the
longevity of the pump and pump motor.
[0064] In accordance with another embodiment of the invention, the
top layer 14 comprises a reflective layer made of a plastic
material, including without limitation polyvinylchloride,
polystyrene, polyethylene or polypropylene, which has a reflective
powder, including without limitation a silver powder, dispersed
therein. Alternatively, the reflective layer may be made of a
sutiable plastic, as described above, with a reflective coating,
such as a silver coating, thereon. Yet another alternative is to
make the reflective layer from a reflective plastic material such
as Mylar, however, such materials tend to be relatively stiff and
rigid and would inhibit rolling up or folding of a pool cover of
any extended length. In all other regards, the structure of the
pool cover is as described above.
[0065] This construction is particularly useful for short term pool
closure up to several weeks without the need for daily maintenance.
External heat, as from solar rays, is reflected away from the pool
of water by the reflective layer. The reflective layer and the
opaque layer inhibit algae growth as light is prevented from
passing into the pool of water. There is a reduction in the water
temperature, as well as a reduction of algae, water evaporation,
and the need for chemicals. In addition, there is no need to run a
pump or a filter. This construction is also of lighter weight and
greater flexibility than the cover described in U.S. Pat. No.
5,511,536. For such a construction, storing the cover with the
reflective surface facing outwards prevents sunlight from heating
and decaying the pool cover and promotes a longer life thereof.
[0066] In an embodiment shown in FIG. 3A, the pool cover 110 is
constructed of three layers 114, 115, 120, each made of plastic
material as described above, each layer having a thickness from
about 1 to about 20 mils, the top layer 114 and bottom layer 120
each being planar, the middle layer 115 being provided with
pockets, and each layer being coextensive with the other
layers.
[0067] As shown in FIG. 3A and in enlargement in FIG. 3B, the pool
cover 110 includes a first top layer 114, a second intermediate
layer 115 having pockets 116, said second layer 115 being secured
to the first layer 114 in any suitable manner as described above so
as to encapsulate air in the pockets 116, and a third bottom layer
120 secured to the surfaces of the pockets 116 of the intermediate
layer 115 in any suitable manner as described above to further
encapsulate air in pockets 121. This construction can be readily
made by sandwiching the intermediate layer 115 between the first
top layer 114 and the third bottom layer 120 in known manner. The
construction of the pockets 116 in the intermediate layer is as
described above with respect to FIGS. 2A-2C. As shown in FIG. 3C,
the rows of pockets 116, 116a are in staggered relation.
[0068] In accordance with an embodiment of the invention, the top
layer 114 comprises a translucent, or preferably transparent, layer
for passing sunlight therethrough. The second intermediate layer
115 also comprises a translucent, or preferably transparent, layer.
The third bottom layer 120 comprises an opaque layer, so as to be
heated by conduction via the sandwiched layer 115. The second
intermediate layer 115 can be made of a non-translucent or opaque
material, although such has been found to be less effective in
heating water 112 in a pool 111. The top layer 114 may alternately
be made of a reflective material, as described above.
[0069] The construction described is such that sunlight passing
through the translucent or transparent layers 114, 115 heats the
opaque layer 120 and the air in the pockets 116, 121 and the opaque
layer 120 conducts the heat to the pool water 112 under the opaque
layer. The air sealed in the pockets 116, 121 forms an insulating
barrier for heat attempting to escape up through the cover 110,
while the opaque layer 121 eliminates, or greatly reduces, the
evaporation from the surface of the water 112 in the pool 111 and
suppresses algae growth.
[0070] In an embodiment shown in FIG. 4, the pool cover 210 is
constructed of three layers 214, 215, 220, each made of plastic
material as described above, each layer having a thickness from
about 1 to about 20 mils, the top layer 214 and bottom layer 220
each being planar, the middle layer 215 being provided with
pockets, and each layer being coextensive with the other layers. In
this embodiment, the air pockets 216 formed in the intermediate
layer 215 are oriented in the opposite direction as in the
embodiment of FIGS. 3A-3C. Thus, the intermediate layer 215 is
sealed to the bottom layer 220 to encapsulate the air in pockets
216 and the top layer 214 is secured to the surfaces of the pockets
216 to further seal air in pockets 221. In all other respects, the
construction and variations therein and the function of pool cover
210 are the same as described with respect to pool cover 110 of
FIGS. 3A-3C.
[0071] As further shown in FIG. 4, the pool cover 210 is preferably
provided with drainage holes 222 preferably in a uniform grid
pattern. Such drainage holes are preferably provided in each
embodiment described above, i.e., cover 10, cover 110, cover 210.
The drainage holes are preferably placed through the air pockets,
16, 116, 216, and are placed in selective ones of said air pockets.
For example, the drainage holes may be placed in one or more rows
of air pockets at spaced intervals along the length of the pool
cover. Thus, one row may have drainage holes and the next ten rows
may not, and this pattern may be continued along the length of the
cover. It has been found that for a pool cover for a 16'.times.32'
pool, it is useful to provide at least about 80 such drainage holes
up to about 200 holes, although fewer or more may be used.
Obviously, with larger covers, more holes are necessary. It is
useful to provide holes at a density of about 1-1/2 to 4 per square
yard.
[0072] These drainage holes reduce water on the top surface of the
cover and promote drying, which reduces heat transfer due to the
reduction of the evaporation process. Also, by keeping the top
surface dry, debris and dirt is free to be blown off the cover in
the same manner in which it is deposited on the cover. And, when
the cover is removed or re-installed, the possibility of water
containing dirt and debris flowing into the pool is reduced or
eliminated. And, rolling or folding of the cover is facilitated due
to the lack of water and debris and dirt thereon. This also reduces
wear and tear on the cover and enhances the life of the cover. The
drainage holes are preferably added after the manufacturing process
and are preferably punctured rather than punched so that there is
substantially no removal of the pool cover material thus minimizing
any light seepage through the holes and also minimizing any
transmission of dirt or debris through the holes.
[0073] As shown in FIG. 5, the pool cover 210 is preferably made
oversized to the surface area of the water 212 in the pool 211 to
permit edge portions 223 thereof to abut the side walls of the pool
211 preferably for several inches and preferably on four sides.
This construction, which is preferably used with any of the
embodiments, pool covers 10, 110, 210, inhibits dirt and debris
from passing into the water and helps lock the cover in place. This
construction also promotes longevity of the pool cover, since such
covers tend to undergo some shrinkage with time.
[0074] In the three layer construction of covers 110 and 210, the
bubble layer is sandwiched between two other layers and is thus
protected so that a sand papering effect does not occur. As a
consequence, the bubble layer can be made thinner than the exterior
layers to reduce the weight and increase the flexibility of such a
three-layer cover. For example, the bubble layer may have a
thickness of 1 mil, while the outer layers may each have a
thickness of 2 mils or greater.
[0075] Generally, the pool cover has a relatively light weight,
from about 1 to about 10 pounds per hundred square feet and
preferably from about 1 to about 8 pounds per hundred square
feet.
[0076] It is also to be understood that the above-described
arrangements are merely illustrative of the many possible
embodiments which represent applications of the present invention.
Numerous and varied other arrangements can readily be devised in
accordance with the principles of the present invention without
departing from the spirit and scope thereof.
* * * * *