U.S. patent application number 10/735774 was filed with the patent office on 2005-06-16 for photosynthesis active radiation blocking solar pool cover and method of making the pool cover.
Invention is credited to Taylor, Michael Allen.
Application Number | 20050125887 10/735774 |
Document ID | / |
Family ID | 34653689 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050125887 |
Kind Code |
A1 |
Taylor, Michael Allen |
June 16, 2005 |
Photosynthesis active radiation blocking solar pool cover and
method of making the pool cover
Abstract
A swimming pool cover which retards algae growth. Two films are
sealed together so as to create air pockets which allow the pool
cover to float on the surface of the water. One or both of the
films contains a material which prevents the passage of light in
those wavelengths which are necessary for algae growth, especially
350-500 nm and 600-700 nm. The material may either be a dye which
has a color associated with that wavelength or may be a transparent
material which removes those wavelengths of light. The remaining
wavelengths of light are allowed to pass through the cover in order
to heat the water but not cause algae growth. Additionally, the
cover can be made by mixing light absorbing material into the
plastic before making the film for the pool cover or may be made by
applying a layer of light absorbing material to the film.
Inventors: |
Taylor, Michael Allen;
(Orillia, CA) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
34653689 |
Appl. No.: |
10/735774 |
Filed: |
December 16, 2003 |
Current U.S.
Class: |
4/498 |
Current CPC
Class: |
E04H 4/103 20130101 |
Class at
Publication: |
004/498 |
International
Class: |
E04H 004/00 |
Claims
It is claimed:
1. An algae retardant pool cover for a pool of water, comprising:
at least one plastic film; said plastic film containing a material
for absorbing light in selected wavelengths necessary for algae
growth.
2. The pool cover according to claim 1, wherein the selected
wavelengths are 350-500 nm and 600-700 nm.
3. The pool cover according to claim 2, wherein the selected
wavelengths are 410 nm, 430 nm, and 453 nm, 642 nm, and 662 nm.
4. The pool cover according to claim 1, wherein the at least one
plastic film includes an upper plastic film and a lower plastic
film, at least one of said upper and lower plastic film containing
material for absorbing light in selected wavelengths necessary for
algae growth.
5. The pool cover according to claim 4, wherein the absorbent
material is contained within one of said upper plastic film and
said lower plastic film.
6. The pool cover according to claim 4, wherein the absorbent
material is applied as an additional layer to one of said upper
plastic film and said lower plastic film.
7. The pool cover according to claim 4, wherein air pockets are
formed between said films to contain air and make said cover float
on water.
8. The pool cover according to claim 1, wherein the absorbent
material is colored in the selected wavelengths.
9. The pool cover according to claim 8, wherein the absorbent
material is colored orange.
10. The pool cover according to claim 8, wherein the absorbent
material is colored blue-green.
11. The pool cover according to claim 1, wherein the absorbent
material is absorbent in the selected wavelengths.
12. The pool cover according to claim 7, wherein the absorbent
material is at least one of sulfates, carbonates, silicates and
silica.
13. An algae retardant pool cover for a pool of water, comprising:
at least one plastic film; and means for absorbing light in
selected wavelengths necessary for algae growth.
14. The pool cover according to claim 13, wherein the selected
wavelengths are 350-500 nm and 600-700 nm.
15. The pool cover according to claim 14, wherein the selected
wavelengths are 410 nm, 430 nm, and 453 nm, 642 nm, and 662 nm.
16. The pool cover according to claim 13, wherein the at least one
plastic film includes an upper plastic film and a lower plastic
film, at least one of said upper and lower plastic film containing
means for absorbing light in selected wavelengths necessary for
algae growth.
17. The pool cover according to claim 16, wherein the absorbent
means is contained within one of said upper plastic film and said
lower plastic film.
18. The pool cover according to claim 16, wherein the absorbent
means is applied as an additional layer to one of said upper
plastic film and said lower plastic film.
19. A method for making an algae retardant pool cover, comprising:
providing material for absorbing light in selected wavelengths
necessary for algae growth; mixing said material into a plastic
material; forming a plastic film including said plastic material
and said material for absorbing light; and forming a pool cover
from said plastic film.
20. A method of making an algae retardant pool cover, comprising:
forming a plastic film; and applying a layer of material for
absorbing light in selected wavelengths necessary for algae growth
onto a surface of said plastic film.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to solar cover for covering
a swimming pool and more particularly to a floating solar cover for
a pool which blocks radiation necessary for algae growth. The
invention further relates to a method for making a floating solar
cover for a pool which blocks radiation necessary for algae
growth.
[0003] 2. Description of the Background
[0004] Swimming pools are enjoyed in many homes as a source of
recreation and as a form of exercise. However, unless a pool heater
is provided or a structure built around the pool, it is difficult
to utilize the pool in seasons other than summer. In order to
extend the usable time of the pool, swimming pool covers have been
developed to prevent the loss of heat when not in use. In
particular, one type of pool cover involves a plastic device with
air pockets which cause the cover to float on the surface. The air
pockets then act as insulation and prevent evaporation of the pool
water as well as convection losses.
[0005] Such a pool cover is seen in U.S. Pat. No. 6,523,190. As
taught there, two films may be sealed in order to form air pockets
which cause the cover to float. In addition, the film may also
contain various infrared absorbing materials within the plastic in
order to absorb infrared radiation which causes the plastic, air
pockets and pool to be heated. Thus, this pool cover not only
prevents losses but also helps to heat the pool when the pool is
not being used.
[0006] While these covers are very effective for preventing heat
loss and even helping to warm the pool and thus providing added
enjoyment for the user in an extended period of use during the
year, it is not helpful for other facets of pool maintenance. One
of the concerns to a swimming pool owner is the growth of algae
within the pool water. Algae grows more quickly in warm water and
accordingly the use of a pool cover to help keep the water warm
actually encourages algae growth. Accordingly, it would be
desirable to use a pool cover which also helps prevent algae
growth.
[0007] Previously, in the area of agriculture, wavelength blocking
to prevent weed development has been utilized. In particular, a
black plastic film has been utilized to block all radiation in
agriculture and by gardeners for many years so as to block any
radiation to plant life below, except where the plants extend
through cuts in the film. This black plastic thus blocks all
radiation. Clear plastic has also been utilized which allows the
transmittance of solar heating to warm the ground below and
increase a crop yield by extending the growing season. Other films
which are wavelength selective are also available in brown and
blue-green colors, which block various wavelengths of light in
order to suppress the growth of weeds. (See Solar Infrared
Transmitting, PAR Absorbing Polyethylene Mulch: Physical Properties
and Crop Responses, J. Brent Loy, Proc. Natl. Agr. Plastics, 1991).
However, this has not been applied to algae suppression.
SUMMARY OF THE INVENTION
[0008] The present invention provides a swimming pool cover which
helps prevent algae growth.
[0009] The present invention further provides a cover for a body of
water which reduces photosynthesis active radiation.
[0010] The present invention further provides a heat-retaining
swimming pool cover which filters out photosynthesis active
radiation to reduce algae growth.
[0011] The present invention still further provides a floatable
heat-retaining swimming pool cover which includes radiation
absorbent materials to retard algae growth.
[0012] The present invention still further provides a method for
making a cover for retarding algae growth.
[0013] These objects are achieved by providing a pool cover using
two plastic films which are sealed together to form air pockets so
that the cover floats and which also contains a radiation absorbent
material within the plastic which removes the wavelengths of
radiation necessary for algae growth.
[0014] Additionally, these objects are achieved by a method for
making an algae retardant pool cover, including providing material
for absorbing light in selected wavelengths necessary for algae
growth, mixing this material into a plastic material, forming a
plastic film including the plastic material and the material for
absorbing light and forming a pool cover from the plastic film.
[0015] Additionally, these objects are achieved by a method of
making an algae retardant pool including forming a plastic film and
applying a layer of material for absorbing light in selected
wavelengths necessary for algae growth on to a surface of the
plastic film.
[0016] Further scope of the applicability of the present invention
will become apparent from the detailed description given
hereinafter. However, it should be understood that the detailed
description and specific examples, while indicating preferred
embodiments of the invention, are given by way of illustration
only, since various changes and modifications within the spirit and
scope of the invention will become apparent to those skilled in the
art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
[0018] FIG. 1 is a cross sectional view of a floatable swimming
pool cover containing air pockets;
[0019] FIG. 2 is a flow chart of a first embodiment of a method of
making a pool cover;
[0020] FIG. 3 is a flow chart of a second embodiment of a method of
making a pool cover;
[0021] FIG. 4 is a cross-sectional view of a second embodiment of a
swimming pool cover.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Referring now to FIG. 1, a pool cover 1 is seen in cross
section. The pool cover is shown as floating on the water 2 within
a swimming pool 3 or other small body of water. Although the
present application is directed to a swimming pool cover, it could
also be used for other pools such as fishponds, or decorative
pools.
[0023] The pool cover includes a plastic upper film 5 and a plastic
lower film 8. The two films are joined together to form air pockets
10 which contain air therein so that the cover will float on the
water. Sealed land areas 11 are formed between the air pockets
where the films maybe sealed to each other.
[0024] The films are generally made of essentially transparent
plastic films such as vinyl or olefin, e.g., polyethylene and
polypropylene, or acetate films. Films may contain a small amount
of tint for cosmetic purposes, such as a light blue tint. The film
may also include infrared absorbent material 15 in order to provide
heat to the water. Light absorbing material 6 is included in upper
film 5. However, it could be included in film 8 alone, or in
both.
[0025] Studies of algae have shown that the chlorophyll contained
therein react to specific wavelengths of lights and these specific
wavelengths are especially necessary for the algae to grow.
Different species of algae require different specific wavelengths.
Providing the wavelengths necessary for one species will stop that
species from growing, but not other species. The specific
wavelengths defined for chlorophyll "A" and "B" (primary mechanisms
for plant life) are centered on peaks at 410 nm, 430 nm, 453 nm,
642 nm and 662 nm. Although there is a small spread around each of
these peak points, most of the necessary light for growth falls in
the region of 350-500 nm and 600-700 nm. Thus, by removing these
wavelengths of light, algae will not grow to any appreciable
extent.
[0026] There are at least two ways to prevent these wavelengths of
light from passing through the pool cover. One method would be to
include a material that because of its color, absorbs the light in
this range. Since the mid 600 nms are typically orange and the low
400 nms are typically violet, some type of dye or other colorant
that contain these colors may be able to absorb these wavelengths
and thus block their passage into the water. Thus, the pool cover
can be made of plastic having an orange color or a color close to
orange, such as red. It also could include an aqua (blue-green)
color or a violet color.
[0027] Another method would be to add certain chemicals which
absorb these specific wavelengths but are not colored themselves.
Materials which absorb these wavelengths to some extent include
sulfates, carbonates, silicates, and silica. Specific compounds
that may be used include, but are not limited to, barium sulfate,
titanium dioxide, magnesium silicate, sodium sulfate, synthetic
amorphous silica, calcite, silicon dioxide, carbon black, and
magnesium hydroxide. By utilizing various of these components or
combinations thereof, the particular wavelengths which generate
algae growth can be removed as light passes through the pool cover
and so block the necessary component of growth for the algae. The
particular mixture of materials may be chosen as desired in order
to attain the best results in wavelength blockage and may also be
chosen due to cost. In addition, it is also possible to mix some of
the colorant material with the non-colored materials from either
for efficiency or cost.
[0028] The first method for making the pool cover is shown in FIG.
2. The material which is added would normally be mixed into a small
amount of resin carrier (step 101) which is then added to the
plastic film (step 102) as it is being generated and before the
pool cover is manufactured (step 103). Thus, the absorbent material
is produced within the films which is simple and economically
feasible. Either the upper film 5 or lower film 8 or both films 5
and 8 can be treated.
[0029] It would also be possible to add these materials as a
separate layer as shown in FIG. 2, but this would require
additional steps and accordingly would be more expensive. This
separate layer could be an additional film between upper film 5 and
lower film 8 or could be on one or both sides of either film 5 or
8. As another alternative, the extra film could be on both exterior
sides of film 5 and 8. Many different combinations should be
apparent to those skilled in the art. Step 201 shows the formation
of plastic films. Step 202 shows the addition of the layer of
light-absorbing material 211 or both of the films. Step 203 shows
the manufacturing of the pool cover from the films.
[0030] This invention has been discussed as being used in a
floatable pool cover with air pockets. However, this invention can
also be used with a non-floatable pool cover that is simply
suspended above a pool or in a pool cover having other means for
floating on this surface of the pool as shown in FIG. 4. The pool
cover 1 is shown floating on the surface of water 2 within a
swimming pool 3, just as in FIG. 1. The cover includes a single
film 21 which is floated on the surface by floats 22. The floats
may be replaced by ropes or other means of suspension, if desired.
The floats or ropes may be attached to the film or the film may
merely be laying loose on the top of the supports.
[0031] Numerous additional modifications and variations of the
present invention are possible in light of the above teachings. It
is therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described.
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