U.S. patent number RE43,492 [Application Number 12/258,091] was granted by the patent office on 2012-06-26 for underwater led light.
This patent grant is currently assigned to Hayward Industries, Inc.. Invention is credited to Ronald H. Griffin, Vitaly Shinkarev, Vance E. Willis.
United States Patent |
RE43,492 |
Willis , et al. |
June 26, 2012 |
**Please see images for:
( Certificate of Correction ) ** |
Underwater LED light
Abstract
An underwater light, e.g., for a pool or spa, includes an
ordinarily watertight housing, an outer compartment within the
housing and floodable by water flowing therein in the event the
housing is no longer watertight, a current shield within the outer
compartment and at least partially defining an inner compartment
within the outer compartment, a light emitter within the inner
compartment, a passageway communicating between the inner and outer
compartments such that outer compartment flood water can enter the
inner compartment and contact the light emitter, and a conductor.
The conductor is positioned so as to collect stray electrical
current conducted from the inner compartment by water within the
passageway, thereby reducing the risk of shock presented by such
stray electrical current. The underwater light is installable
within a wet niche, and includes a transformer housed in a separate
compartment that extends into the wet niche for thorough cooling
thereof.
Inventors: |
Willis; Vance E. (Nunnelly,
TN), Griffin; Ronald H. (Boonville, NC), Shinkarev;
Vitaly (Greensboro, NC) |
Assignee: |
Hayward Industries, Inc.
(Elizabeth, NJ)
|
Family
ID: |
35513674 |
Appl.
No.: |
12/258,091 |
Filed: |
October 24, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
10880755 |
Jun 30, 2004 |
7125146 |
Oct 24, 2006 |
|
|
Current U.S.
Class: |
362/267; 340/852;
362/249.02; 362/158 |
Current CPC
Class: |
F21S
8/00 (20130101); F21V 23/005 (20130101); F21V
23/006 (20130101); F21V 29/56 (20150115); F21V
25/00 (20130101); F21V 23/002 (20130101); F21Y
2105/10 (20160801); F21Y 2115/10 (20160801); F21V
31/005 (20130101); F21W 2131/401 (20130101) |
Current International
Class: |
F21V
29/00 (20060101) |
Field of
Search: |
;362/101,158,267
;340/850-852 ;361/212,215,232,799 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
UL Safety Standard 676, entitled "Underwater Luminaires and
Submersible Junction Boxes," printed from Internet website
http://ulstandardsinfonet.ul.com/scopes/0676.html (Jan. 24, 2006)
(1 page). cited by other .
UL Safety Standard 676, entitled "Underwater Luminaires and
Submersible Junction Boxes," printed from Internet website
http://ulstandardsinfonet.ul.com/0676.html (Jan. 24, 2006). cited
by other.
|
Primary Examiner: Han; Jason Moon
Attorney, Agent or Firm: McCarter & English, LLP
Claims
What is claimed is:
1. An underwater light, comprising.Iadd.: .Iaddend. an ordinarily
watertight housing; an outer compartment within said housing, said
outer compartment being subject to flooding by water flowing
therein from outside said housing in the event said housing is no
longer watertight; a current shield disposed within said outer
compartment, said current shield at least partially defining an
inner compartment within said .[.outer compartment;.].
.Iadd.housing, said current shield inhibiting a stray electrical
current from escaping said inner compartment when said housing is
no longer watertight and said inner compartment is subject to
flooding by water flowing therein;.Iaddend. a light emitter
disposed within said inner compartment; .[.a passageway
communicating between said inner compartment and said outer
compartment such that at least a portion of any water flooding said
outer compartment can enter said inner compartment and come into
contact with said light emitter; and.]. .Iadd.and .Iaddend. a
conductor positioned so as to collect .[.any and substantially
all.]. .Iadd.the .Iaddend.stray electrical current .[.that may be
conducted.]. from said inner compartment .[.by water within said
passageway.]., thereby reducing the risk of electrical shock
presented by .[.such.]. .Iadd.the .Iaddend.stray electrical
current.
2. The underwater light of claim 1, wherein said conductor includes
an electrically conductive surface which at least partially defines
.[.said passageway..]. .Iadd.a passageway between said inner and
outer compartments..Iaddend.
3. The underwater light of claim 2, wherein said current shield
includes an electrically insulative surface which at least
partially defines said passageway, said electrically insulative
surface being disposed opposite said electrically conductive
surface so as to cause any and all stray electrical current that
may be conducted from said inner compartment by water within said
passageway to pass along and in close proximity to said
electrically conductive surface, thereby facilitating the
collection of such stray electrical current by said conductor.
4. The underwater light of claim 3, wherein said current shield is
dome-like in shape and includes a lower peripheral edge which
includes said electrically insulative surface.
5. The underwater light of claim 3, wherein at least a portion of
said electrically insulative surface is in physical contact with
said electrically conductive surface.
6. The underwater light of claim 3, wherein said electrically
insulative surface and said electrically conductive surface are
separated by a gap.
7. The underwater light of claim 6, wherein said gap is not more
than about 0.1 inches.
8. The underwater light of claim 6, wherein said gap is not more
than about 0.02 inches.
9. The underwater light of claim 4, wherein said lower peripheral
edge of said current shield has a width of not less than about 0.04
inches.
10. The underwater light of claim 4, wherein said lower peripheral
edge of said current shield has a width in a range from about 0.05
inches to about 0.07 inches.
11. The underwater light of claim 2, wherein said conductor is
adapted for connection to an electrical ground.
12. The underwater light of claim 2, wherein said conductor
includes a metal plate, and said conductive surface is a portion of
said metal plate.
13. The underwater light of claim 12, wherein said light emitter is
mounted to said metal plate.
14. The underwater light of claim 1, wherein said light emitter
includes an array of light emitting diodes.
15. The underwater light of claim 1, wherein said housing includes
a lens which defines at least a portion of said outer
compartment.
16. The underwater light of claim 15, wherein said lens is made
from glass.
17. The underwater light of claim 15, wherein said current shield
is made from translucent plastic and is disposed between said lens
and said light emitter.
18. The underwater light of claim 15, wherein said current shield
is made from transparent plastic.
19. The underwater light of claim 1, further comprising a
transformer compartment spaced apart from said inner and outer
compartments by a distance sufficiently long so as to permit a free
flow of water in a space between said transformer compartment and
said inner and outer compartments for efficient removal of heat
therefrom.
20. An assembly comprising the underwater light of claim 19
installed within a wet niche of standard size for a below-ground
spa installation.
.Iadd.21. An underwater light, comprising: an ordinarily watertight
housing; an outer region within said housing, said outer region
being subject to flooding by water flowing therein from outside
said housing in the event said housing is no longer watertight; a
current shield disposed within said housing, said current shield at
least partially defining an inner region within said housing, said
current shield inhibiting a stray electrical current from escaping
said inner region when said housing is no longer watertight and
said inner region is subject to flooding by water flowing therein;
a light emitter disposed within said inner region; and a conductor
positioned so as to collect the stray electrical current from said
inner region, thereby reducing the risk of electrical shock
presented by the stray electrical current..Iaddend.
.Iadd.22. The underwater light of claim 21, wherein said conductor
includes an electrically conductive surface which at least
partially defines a passageway between said inner and outer
regions..Iaddend.
.Iadd.23. The underwater light of claim 22, wherein said current
shield includes an electrically insulative surface which at least
partially defines said passageway, said electrically insulative
surface being disposed opposite said electrically conductive
surface so as to cause any and all stray electrical current that
may be conducted from said inner region by water within said
passageway to pass along and in close proximity to said
electrically conductive surface, thereby facilitating the
collection of such stray electrical current by said
conductor..Iaddend.
.Iadd.24. The underwater light of claim 23, wherein said current
shield is dome-like in shape and includes a lower peripheral edge
which includes said electrically insulative surface..Iaddend.
.Iadd.25. The underwater light of claim 23, wherein at least a
portion of said electrically insulative surface is in physical
contact with said electrically conductive surface..Iaddend.
.Iadd.26. The underwater light of claim 23, wherein said
electrically insulative surface and said electrically conductive
surface are separated by a gap..Iaddend.
.Iadd.27. The underwater light of claim 26, wherein said gap is not
more than about 0.1 inches..Iaddend.
.Iadd.28. The underwater light of claim 26, wherein said gap is not
more than about 0.02 inches..Iaddend.
.Iadd.29. The underwater light of claim 24, wherein said lower
peripheral edge of said current shield has a width of not less than
about 0.04 inches..Iaddend.
.Iadd.30. The underwater light of claim 24, wherein said lower
peripheral edge of said current shield has a width in a range from
about 0.05 inches to about 0.07 inches..Iaddend.
.Iadd.31. The underwater light of claim 22, wherein said conductor
is adapted for connection to an electrical ground..Iaddend.
.Iadd.32. The underwater light of claim 22, wherein said conductor
includes a metal plate, and said conductive surface is a portion of
said metal plate..Iaddend.
.Iadd.33. The underwater light of claim 32, wherein said light
emitter is mounted to said metal plate..Iaddend.
.Iadd.34. The underwater light of claim 31, wherein said light
emitter includes an array of light emitting diodes..Iaddend.
.Iadd.35. The underwater light of claim 31, wherein said housing
includes a lens which defines at least a portion of said outer
region..Iaddend.
.Iadd.36. The underwater light of claim 35, wherein said lens is
made from glass..Iaddend.
.Iadd.37. The underwater light of claim 35, wherein said current
shield is made from translucent plastic and is disposed between
said lens and said light emitter..Iaddend.
.Iadd.38. The underwater light of claim 35, wherein said current
shield is made from transparent plastic..Iaddend.
.Iadd.39. The underwater light of claim 31, further comprising a
transformer compartment spaced apart from said inner and outer
regions by a distance sufficiently long so as to permit a free flow
of water in a space between said transformer compartment and said
inner and outer regions for efficient removal of heat
therefrom..Iaddend.
.Iadd.40. An assembly comprising the underwater light of claim 39
installed within a wet niche of standard size for a below-ground
spa installation..Iaddend.
.Iadd.41. An underwater light, comprising: an ordinarily watertight
housing provided with a lens area ordinarily occupied by a lens; an
outer region within said housing, said outer region being subject
to flooding by water flowing therein from outside said housing in
the event said housing is no longer watertight; a current shield
disposed within said housing, said current shield at least
partially defining an inner region within said housing, said
current shield inhibiting a stray electrical current from escaping
said inner region when said housing is no longer watertight and
said inner region is subject to flooding by water flowing therein;
a light emitter disposed within said inner region; and a conductor
positioned so as to collect the stray electrical current from said
inner region, thereby reducing the risk of electrical shock
presented by the stray electrical current; wherein said current
shield guides the stray electrical current to said conductor when
said inner region is flooded..Iaddend.
.Iadd.42. The underwater light of claim 41, wherein said current
shield comprises a span..Iaddend.
.Iadd.43. The underwater light of claim 42, wherein said span
comprises a material that is at least one of transparent and
translucent..Iaddend.
.Iadd.44. The underwater light of claim 43, wherein said span
comprises a polymer..Iaddend.
.Iadd.45. The underwater light of claim 41, comprising a lens
occupying said lens area at least when said housing is
watertight..Iaddend.
Description
FIELD OF THE INVENTION
The present invention relates to submergible lights and light
fixtures and, more particularly, to underwater LED lights for use
in swimming pools and spas.
BACKGROUND OF THE INVENTION
Modern designs for swimming pools and spas commonly provide for
illumination of the pool or spa from beneath the waterline. For
example, underwater light assemblies equipped with glass or plastic
external lenses can be installed on and/or in the wall of a pool or
spa below the waterline such that part or all of the external lens
faces into the pool or spa, and is exposed to the water contained
therein. Typically the external lens of such a light at least
partially defines a water-tight illumination compartment of the
light within which the light-emitting element or light emitter is
mounted. While such an arrangement can be advantageous from the
standpoint of illumination efficiency, it has long been recognized
that such light assemblies can pose a risk of electric shock to
bathers, especially if deliberate steps to mitigate this risk are
not taken (e.g., during the product design phase). For example,
should the water-tight integrity of the compartment containing the
light emitter become compromised (e.g., while the pool and the
light assembly are in use, and/or during pool or light assembly
maintenance, etc.) and pool or spa water is admitted therein, a
direct path of conductive water could be created along which
current, previously contained within the light assembly, could
stray into the main body of the pool or spa.
At least one commonly followed standard for safety with respect to
such underwater lights, namely, Standard for Safety for Underwater
Luminaires and Submersible Junction Boxes, UL 676, eighth edition,
dated Jun. 9, 2003 and developed and maintained by Underwriter's
Laboratories Incorporated of Northbrook Ill., recognizes that there
are many different ways in which the risk to bathers of electrical
shock from such underwater lights can be reduced and/or eliminated.
In accordance with the UL 676 standard, many manufacturers have,
for example, developed underwater lights with external lenses made
of certain modern plastic and/or other polymeric materials, such as
polycarbonate (e.g., from the LEXAN series of
polycarbonate/plastics resins manufactured by General Electric
Co.), or polycarbonate alloy, and in this way have obtained the
desired safety certification. By choosing this design path, such
manufacturers are essentially relying on the basic toughness and
resiliency of such materials to avoid lens degradation via such
stressors as impact shock, thermal shock, fatigue-inducing thermal
cycling, etc. Unfortunately, such materials also have drawbacks in
comparison to more traditional lens materials, such as optical
glass and/or similar (i.e., glass-like) materials. For example,
such plastic or polymeric materials tend to become internally
cloudy over time, and are typically not very scratch-resistant.
This limits their utility, at least with respect to certain
underwater light markets, such as the market for commercial and
high-end consumer pool and spas, in which premiums are often placed
on such characteristics as overall aesthetic appearance, and/or
sustained brightness/luminosity, etc.
Seeking to service such markets, some other manufacturers produce
high-quality underwater lights equipped with external lenses made
from the more traditional glass or glass-like materials.
Unfortunately, such lenses tend not to exhibit the type of strength
and toughness which characterizes the above-mentioned plastic and
polymer-type lenses. Accordingly the external lenses of such
underwater lights are characteristically more likely to fail the
impact and/or thermal shock tests associated, for example, with the
above-mentioned UL 676 safety standard. In such circumstances, in
order to achieve the desired safety certification with respect to
the risk of shock from stray electrical current, design solutions
must generally be devised and implemented which ensure that, even
in the event of a complete fracture of the external lens, resulting
in a complete flooding of the light fixture and/or a short in the
applicable electrical and/or electronic circuit, the shock risk to
nearby bathers is nevertheless still acceptable. Some such design
solutions are disclosed in U.S. Patent Application Publication No.
2002/0101198, and in U.S. Pat. Nos. 3,949,213; 4,234,819;
5,545,952; and 5,842,771. Accordingly, design solutions for
underwater lights shown to reduce the shock risk to nearby bathers
to acceptable levels are both necessary and desirable.
In addition to contending with issues relating to the risk of
electrical shock to nearby bathers, manufacturers of high quality
underwater lights must ensure that, to the extent excessive heat is
generated by the various components thereof, e.g., light-emitting
elements, transformers, microprocessors (if applicable), etc., such
heat is promptly and efficiently conducted away from the light. In
particular, certain types of underwater lights, e.g., underwater
lights equipped with one or more LED arrays, tend to produce heat
in such quantity that the effectiveness of the methods and
apparatus employed therein for heat removal is critical to issues
such as safe operation and product reliability/durability.
Especially in light of the current trend toward brighter and
brighter underwater lights, including underwater lights producing
white light via the simultaneous illumination of separate arrays of
blue, red and green LEDs, the development and deployment of
effective new methods and apparatus for conducting heat from
underwater lights is an industry priority.
SUMMARY OF THE INVENTION
The present invention overcomes the disadvantages and shortcomings
of the prior art discussed above by providing a new and improved
underwater light for use in spas, pools, and the like which
substantially reduces and/or eliminates the risk of shock to nearby
bathers from stray electrical current escaping from the light. More
particularly, the underwater light includes a housing, an outer
compartment within the housing, a current shield within the outer
compartment and at least partially defining an inner compartment
within the outer compartment, and a light emitter within the inner
compartment. Ordinarily, the housing is water tight, but in the
event the housing is no longer watertight (e.g., due to accidental
damage to the housing, such as a lens fracture), the outer
compartment is subject to flooding by water flowing therein. The
underwater light further includes a passageway communicating
between the inner and outer compartments such that flood water in
the outer compartment can enter the inner compartment and come into
contact with the light emitter. The underwater light further
includes a conductor positioned so as to collect stray electrical
current conducted from the inner compartment by water within the
passageway and thereby reduce a risk of shock presented by such
stray electrical current.
In accordance with one aspect of the current invention, the
conductor is grounded and includes an electrically conductive
surface which at least partially defines the passageway. In
accordance with another aspect of the invention, an electrically
insulative surface of the current shield is disposed opposite the
electrically conductive surface. In accordance with a further
aspect of the invention, the underwater light further includes a
transformer compartment spaced apart from the inner and outer
compartments by a distance sufficiently long so as to permit a free
flow of water in a space between the transformer compartment and
the inner and outer compartments for efficient removal of heat
therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention,
reference is made to the following detailed description of
exemplary embodiments of the present invention, considered in
conjunction with the accompanying drawings, in which:
FIG. 1 is a perspective exploded view of an underwater light
assembly constructed in accordance with a first embodiment of the
present invention;
FIG. 2 is a perspective exploded view of a backplate/PCA assembly
of the underwater light assembly shown in FIG. 1;
FIG. 3 is a side cross-sectional view of the underwater light
assembly shown in FIG. 1;
FIG. 4 is a side cross-sectional view of the underwater light
assembly of FIG. 1, shown assembled within a wet niche;
FIG. 5 is a perspective exploded view of an underwater light
assembly constructed in accordance with a second embodiment of the
present invention;
FIG. 6 is a perspective exploded view of a backplate/PCA assembly
of the underwater light assembly shown in FIG. 5;
FIG. 7 is a side cross-sectional view of the underwater light
assembly shown in FIG. 5; and
FIG. 8 is a side cross-sectional view of the underwater light
assembly of FIG. 5, shown assembled within a wet niche.
DETAILED DESCRIPTION OF THE INVENTION
Although the present invention can be used in conjunction with any
type of underwater lighting application, it is particularly
suitable for use in connection with pools, spas, baths and the
like. Accordingly, the present invention will be described
hereinafter in connection with swimming pool and spa lighting
applications. It should be understood, however, that the following
description is only meant to be illustrative of the present
invention and is not meant to limit the scope of the present
invention, which has applicability to other types of underwater
applications, such as aquariums, fish ponds, water park rides,
venues for viewing aquatic animal performances, etc.
Referring to FIG. 1, there is shown in perspective exploded view an
underwater light assembly 10 for use in a swimming pool. The
underwater light assembly includes a backplate/PCA assembly 12, a
lens gasket 14, a lens 16, a body 18, and a face plate 20.
The backplate/PCA assembly 12 of FIG. 1 is shown in another
exploded assembly perspective view in FIG. 2. As shown in FIG. 2,
the backplate/PCA assembly 12 includes a backplate 22, a printed
circuit assembly 24, and a current shield 26. The backplate 22
includes an interior surface 28 which is both electrically
conductive and grounded. The printed circuit assembly 24 is secured
directly to the interior surface 28 via thermally conductive
adhesive so as to facilitate conductive cooling of the printed
circuit assembly 24 during high-voltage operation. The printed
circuit assembly 24 includes a transformer 30 for receiving
external 120V A/C power and stepping the same down to 36V A/C
power, as well as rectifier circuitry (not shown) to convert the
36V A/C output of the transformer to 36V D/C for use as internal
power. The external A/C power is supplied to the underwater light
assembly 10 via electrical leads (not shown) contained in an
electrical conduit 32 secured to the rear of the backplate 22 and
connected to the printed circuit assembly 24 in a conventional
fashion via an access hole 34 (otherwise plugged with potting
material, and therefore water-tight) in the backplate 22. Grounding
of the backplate 22 and the printed circuit assembly 24 is
accomplished in a similar fashion, via respective grounding posts
36 attached thereto for the purpose.
The printed circuit assembly 24 is employed as a light emitter, and
includes a front side 38 populated by a plurality of light-emitting
diodes (LEDs) 40 arranged in three separately controllable arrays
for emitting red, green, and blue light, respectively. As such, any
one such LED array may be illuminated alone, or more than one such
LED array may be illuminated simultaneously. Various colors and
intensities of light may thereby be produced, at the discretion of
the user, including white light of considerable brightness.
The current shield 26 is formed from transparent plastic so as to
permit substantially all light produced by the LEDs 40 on the
printed circuit assembly 24 to reach the lens 16, and thereby be
emitted into the pool water. Of simple construction, the current
shield 26 is relatively thin (i.e., 0.06 inches) and is
dome-shaped, having a top span 42, and side walls 44 which extend
downward from the top span 42, terminating in an edge 46, circular
in shape, and forming a downward-facing electrically insulative
surface (not separately shown) disposed opposite the interior
surface 28 of the backplate 22. The current shield 26 also includes
an interior surface 48 (see FIG. 3) which is substantially
imperforate (i.e., with the exception of an axially-positioned
through hole 50 (FIG. 2) in the top span 42 for the accommodation
of mounting hardware). These characteristics of the current shield
26 prevent such water as may impinge against the interior surface
48 from passing therethrough, and/or through the entire thickness
of the current shield 26 (see, hereinafter, the related discussion
regarding pool water flooding the underwater light assembly 10).
The plastic material of the current shield 26, being also
electrically insulative, also prevents electrical current disposed
on or near the interior surface 48 of the current shield 26 from
penetrating the current shield 26.
Referring to FIG. 3, a side cross-sectional view of the underwater
light assembly 10 is shown. As shown in FIG. 3, the lens 16, which
is made of optical glass, includes an interior surface 52. The
interior surface 52 of the lens 16, in combination with the lens
gasket 14, the interior surface 28 and sealed access hole 34 of the
backplate 22, and the front side 38 of the printed circuit assembly
24, defines an outer compartment 54 within the underwater light
assembly 10. At least the LEDs 40 (and associated electronics) and
the current shield 26 are contained within the outer compartment
54. The body 18 of the underwater light assembly 10 is secured to
the backplate 22 via appropriate mounting hardware, and the face
plate 20 is secured to the body. The lens 16 and the lens gasket 14
are thereby clamped between the backplate 22 and the body 18. As a
result of this arrangement, the lens gasket 14 is compressed, and
the ordinarily dry outer compartment 54 is rendered substantially
water-tight.
As also shown in FIG. 3, the current shield 26 is secured to the
backplate 22 via a screw 56 passing through the through-hole 50
(FIG. 2), along with other conventional mounting hardware,
including a standoff 58. The standoff 58 extends upward from the
front surface 38 of the printed circuit assembly 24, and is of
sufficient height to ensure that the above-described method of
securing the current shield 26 to the backplate 22 results in the
edge 46 of the current shield 26 abutting the conductive interior
surface 28 of the backplate 22. As a result, a simple,
non-watertight interface is formed therebetween, having a width
equivalent to the thickness of the edge 46 of the current shield
26. An inner compartment 60 within the outer compartment 54 is
defined at least in part by the interior surface 48 of the current
shield 26, the interior surface 28 and sealed access hole 34 of the
backplate 22, and the front side 38 of the printed circuit assembly
24. To the extent water is permitted to flow through the
non-watertight interface between the edge 46 of the current shield
26 and the conductive interior surface 28 of the backplate 22, that
interface may be considered a passageway communicating between the
inner compartment 60 and the outer compartment 54.
With respect to normal underwater lighting operation, for purposes
of the present discussion, the underwater light assembly 10
functions in a manner similar to conventional underwater lights
equipped with printed circuit assemblies populated with LEDs as the
principle light emitters or lighting elements. However, the
underwater light assembly 10 further performs a stray electrical
current collection function, as described below.
In the event the watertight integrity of the outer compartment 54
is compromised (e.g., via a crack in the lens 16 caused by impact
trauma), pool water may be expected to flood the outer compartment
54 of the underwater light assembly 10. A portion of such flood
water may be expected to further invade the inner compartment 60 by
flowing through the non-watertight interface (or passageway)
between the edge 46 of the current shield 26 and the interior
surface 28 of the backplate 22. Such invading flood water could
then contact the printed circuit assembly 24, causing an electrical
short in the high-voltage and/or power supply electronics thereof.
As a result of such a short, electrical current previously
contained within the printed circuit assembly 24 may be expected to
escape therefrom, after which such stray electrical current will be
borne by a volume of flood water adjacent to and impinging against
the printed circuit assembly 24. Presuming, temporarily, that the
above-mentioned current shield 26 is absent from of the underwater
light assembly 10, the compromised watertight integrity of the
outer compartment 54 would give rise to a significant risk that a
considerable amount of such stray electrical current would be
conducted through the flood water, out of the outer compartment 54,
and into the main body of pool water, placing nearby bathers at
risk of electrical shock.
Given, however, that the current shield 26 both exists and is
assembled to the backplate 22 as described above, any such stray
electrical current (indicated by corresponding arrows within the
inner compartment 60) has no other route to escape from the inner
compartment 60 and into the compromised outer compartment 54 except
along one or more continuous paths of conductive flood water
leading through the non-watertight interface or passageway between
the edge 46 of the current shield 26 and the interior surface 28 of
the backplate 22. Prototype tests of the underwater light of the
present invention, conducted in accordance with the provisions of
UL 676 (see the Background section above), have demonstrated that
most, if not substantially all such stray electrical current does
not, in fact, emerge from the inner compartment 60 and enter the
compromised outer compartment 54. While not desiring to be bound by
theory, applicants believe that a combination of an adequate
thickness of the edge 46 of the current shield 26, the close
proximity of the edge 46 to the interior surface 28 of the
backplate 22, the conductive characteristics of the interior
surface 28, and the path to ground originating therefrom, causes
substantially all such stray electrical current (e.g., such stray
electrical current as enters the relevant interface) to pass
entirely out of the flood water, enter the backplate 22 via the
adjacent interior surface 28, and flow directly to ground. As a
result, little to no such stray electrical current actually escapes
the underwater light assembly 10, and nearby bathers are
well-protected from electrical shock. As the terms "substantially
all stray electrical current" and "any and substantially all stray
electrical current" are used herein, at least one meaning each term
shall be considered to have is the following: enough such stray
electrical current to ensure that the maximum acceptable levels of
stray electrical current escaping the underwater light, according
to a conventional standard such as UL 676, are adhered to.
It should be appreciated that the underwater light assembly 10 of
the present invention provides numerous advantages over the prior
art discussed above. For example, with the risk of electric shock
from stray electrical current lowered to an acceptable level by
guiding the stray electrical current from the flood water to ground
by operation of the current shield 26, the selection of materials
for the lens 16 is not restricted by a desire to maximize toughness
or resiliency to prevent fracture thereof. As a result, the lens 16
may comprise any otherwise suitable material, including but not
limited to glass and glass-type materials, which tend to retain a
scratch-free non-cloudy appearance. Also, the higher thermal
conductivity of glass contributes to the important function of
cooling the underwater light assembly through the external
interface between the lens 16 and the pool water, an especially
important consideration in the current context because of the
tendency of LEDs to run very hot. Further, the grounding
arrangement is relatively simple (e.g., very few parts), reliable
(e.g., no moving parts or "solid state"), and inexpensive (e.g.,
the current shield 26 can be manufactured in large quantities from
inexpensive plastic materials via conventional molding techniques,
and the current shield 26 itself takes up very little otherwise
useable space within the outer compartment 54).
It should be noted that the underwater light assembly 10 of the
present invention can have numerous modifications and variations.
For instance, the LEDs 40 may be replaced with other types of
light-emitting elements, and the printed circuit assembly 24 may be
eliminated and/or replaced by other equipment designed to support,
control, and/or provide power to the light-emitting elements. By
way of example, the underwater light assembly 10 may include one or
more incandescent or halogen bulbs, and/or neon lights, etc., with
appropriate sockets. The 120V A/C external power routed to the
underwater light assembly 10 may be replaced by 12V A/C external
power (in which case the transformer 30 can be configured to step
the external power up to 36V A/C), 12V D/C external power, and/or
A/C or D/C power defined by an alternative standard, or by no
particular standard. The backplate 22, ordinarily metallic (e.g.,
ASTM A 240 Type 304 18GA Stainless Steel), may comprise one or more
non-metallic materials (e.g., ceramic, glass, plastic) provided the
replacement material or collection of materials provide adequate
conductive cooling for the printed circuit assembly 24, and an
adequate amount of conductive, grounded material is provided
at/along the interior surface 28 of the backplate 22 at its
current-collecting interface with the current shield 26.
The dome-shaped current shield 26 can be replaced by a current
shield of any suitable shape, including planar, oblong,
rectangular, and/or polygonal, etc., or thickness, including
thicknesses greater than or less than its 0.06'' thickness. The
plastic material (e.g., transparent polycarbonate, such as GE
Plastics LEXAN 953A) of the current shield 26 may be replaced by
other electrically insulative materials providing good light
transmissibility, such as one or more types of glass. A current
shield which is translucent, but not specifically transparent, may
be used if desired. Small gaps in the edge 46 of the current shield
26 (and/or in the conductivity of the interior surface 28 of the
backplate 22 opposite the edge 46) or small perforations in the
current shield 26 are allowable to the extent they do not result in
the amount of escaping stray electrical current exceeding the
maximum allowable under the applicable safety standard (e.g., UL
676). Multiple materials may be employed for the current shield 26,
e.g., in combination, such as in layers, and/or thin coatings. In
addition, the interior surface 28 of the current shield 26 need not
be completely electrically insulative (e.g., it may be at least
partially electrically conductive, e.g., via a thin
electrodeposited metal layer), provided current is still prevented
from flowing through the current shield 26 across its
thickness.
The edge 46 and the interior surface 28 meet along a circular
peripheral interface. However it is not necessary that such an
interface be circular. As such, the interface may describe one or
more other shapes, in addition or alternatively, including oblong,
curved but having at least one straight side, polygonal, etc.
The edge 46 and the interior surface 28 are in physical contact
along corresponding peripheral surfaces (not separately shown)
which are complementary at least in that both are substantially
planar. As such, the flatness of the resulting interface can be
controlled if necessary by easily-achieved flatness tolerances
along with adequate material stiffness, and the width of the
resulting interface can be controlled by specifying an appropriate
thickness for the current shield 26 and/or an appropriate radial
width of an annular conductive surface of the interior surface 28
of the backplate 22. However, the corresponding peripheral surfaces
need not be necessarily flat and/or planar in shape. For example,
the peripheral surfaces (not separately shown) may describe one or
more shapes (e.g., in addition to planar/flat, or alternatively
thereto) such as curved, frustoconical, cylindrical, and/or
labyrinthine, etc., while remaining effective from a stray
electrical current collection standpoint.
The current shield 26 can be assembled to the backplate 22 in such
a way as to create a partial (e.g., incomplete, intermittent,
and/or irregular, etc.) or even continuous (e.g., complete) gap
between the edge 46 and the interior surface 28. Such a gap or
series of gaps can grow or shrink accordingly (e.g., according to
an iterative design process), in keeping with a goal of reducing
the amount of water-borne stray electrical current which is allowed
to escape from the inner compartment 60 to an acceptably low level.
While the present applicants observe that a gap of more than 0.1
inches or more can be acceptable in certain instances, a gap 0.1
inches or less, and in particular a gap of 0.02 inches or less, has
been observed to provide excellent stray electrical current
collection results in conjunction with an interface which is
otherwise permeable to flood water. Similarly, while the present
applicants observe that a current shield 26 having a edge width or
edge thickness of less than 0.04 inches can be acceptable in some
instances, an edge thickness of 0.04 inches or greater, and in
particular an edge thickness in a range of about 0.05 inches to
about 0.07 inches, has been observed to provide excellent stray
electrical current collection results. While edge thicknesses
larger than 0.07 inches are acceptable in many instances,
applicants have observed current shields 26 having relatively
shorter edge thicknesses can be superior from a light transmission
standpoint (e.g., presuming such current shields 26 to be of
substantially uniform thickness). A current shield 26 having a
non-uniform thickness (i.e., thicker at the edge 46 than elsewhere)
can also be used.
Referring to FIG. 4, the underwater light assembly 10 (shown, for
purposes of a simplified illustration, without certain internal
components such as the printed circuit assembly 24, the current
shield 26, etc.) can be installed within an appropriate wet niche
62, e.g., Hayward Pool Product's SP0604C wet niche, such that pool
water flowing in and out of an inner chamber 64 of the wet niche 62
may be used to cool a rear surface 66 of the backplate 22. Such wet
niches are often built into concrete pool walls, and their use can
be especially beneficial when, as in the present invention, the
underwater light employed is equipped with multiple high-intensity
LEDs requiring relatively rapid rates of heat removal to ensure
their operating temperatures remain within an acceptable range.
A second exemplary embodiment of the present invention is
illustrated in FIGS. 5 8. Elements illustrated in FIGS. 5 8, which
correspond substantially to the elements described above with
respect to FIGS. 1 4, have been designated by corresponding
reference numerals increased by one hundred. The embodiment of the
present invention shown in FIGS. 5 8 operates and is constructed in
a manner consistent with the foregoing description of the
underwater light assembly shown in FIGS. 1 4, unless it is stated
otherwise.
In FIGS. 5 7, there is shown an underwater light assembly 110
constructed in accordance with a second embodiment of the present
invention, and suitable for use in a spa. Referring to FIG. 5, in
addition to a backplate/PCA assembly 112, a lens gasket 114, a lens
116, a body 118, and a face plate 120, the underwater light
assembly 110 includes a separate transformer compartment 168 which
includes a base 170 and a rear cover 172 for separately housing a
transformer 130, which steps exterior 120V A/C power down to 12V
A/C.
Referring to FIG. 6, the backplate/PCA assembly 112 of FIG. 5 is
shown in another exploded assembly perspective view. As shown in
FIG. 6, the backplate/PCA assembly 112 includes a backplate 122, a
printed circuit assembly 124, and a current shield 126. The
backplate 122 includes an interior surface 128 which is both
electrically conductive and grounded. The printed circuit assembly
124 is secured directly to the interior surface 128 via thermally
conductive adhesive so as to facilitate conductive cooling of the
printed circuit assembly 124 during lighting operation. The printed
circuit assembly 124 does not include a transformer, unlike the
printed circuit assembly 24 of the embodiment of FIGS. 1 4. Rather,
the transformer 130 (FIG. 5) of the underwater light assembly 110
is separately mounted, as is mentioned above, and as will be
explained in more detail hereinafter. 12V A/C power is supplied to
the printed circuit assembly 124 via electrical leads 174 extending
from the transformer compartment 168 (FIG. 5) connected to the
printed circuit assembly 124 in a conventional fashion via an
unsealed access hole 134 in the backplate 122, and is converted
therein by rectifier circuitry (not shown) to 12V D/C for use as
internal power. Grounding of the backplate 122 and the printed
circuit assembly 124 is accomplished in a similar fashion, via
respective grounding posts 136 attached thereto for such
purpose.
The printed circuit assembly 124 includes a front side 138
populated by a plurality of light-emitting diodes (LEDs) 140
arranged in three separately controllable arrays for emitting red,
green, and blue light, respectively. As such, any one such LED
array may be illuminated alone, or more than one such LED array may
be illuminated simultaneously. Various colors and intensities of
light may thereby be produced, at the discretion of the user,
including white light of considerable brightness. The printed
circuit assembly 124 is considerably smaller than the printed
circuit assembly 24 of the embodiment of FIGS. 1 4 so as to conform
to the prevailing diametrical size standard for built-in spa light
fixtures such as the underwater light assembly 110. As such, it is
significant that the printed circuit assembly 124 is not populated
by a 120V A/C to 12V A/C transformer, since the space that such a
transformer would otherwise have occupied on the front side 138 of
the printed circuit assembly 124 becomes available for population
by additional LEDs 140. As shown in FIG. 6, such LEDs 140 have in
fact been added to the printed circuit assembly with a result being
that the maximum intensity of the light produced by the underwater
light assembly 110 is increased significantly over what would
otherwise be the case.
The current shield 126 is formed from transparent plastic so as to
permit substantially all light produced by the LEDs 140 on the
printed circuit assembly 124 to reach the lens 116, and thereby be
emitted into the pool water. Of simple construction, the current
shield 126 is relatively thin (i.e., 0.06 inches), and has a top
span 142, and side walls 144 which extend downward from the top
span 142, terminating in an edge 146, circular in shape, and
downward-facing for close communication along the width of the edge
146 with the interior surface 128 of the backplate 122. The current
shield 126 also includes an interior surface 148 (see FIG. 7) which
is substantially imperforate (i.e., with the exception of two
through holes 150 (FIG. 6) in the top span 142 for the
accommodation of mounting hardware).
Referring to FIG. 7, a side cross-sectional view of the underwater
light assembly 110 is shown. The interior surface 152 of the lens
116, in combination with the lens gasket 114, the interior surface
128 the backplate 122, and the front side 138 of the printed
circuit assembly 124, defines an outer compartment 154 within the
underwater light assembly 110. (The access hole 134, because it is
not sealed, causes the transformer compartment 168 to communicate
with the outer compartment 154 while remaining physically separate
therefrom.)
As also shown in FIG. 7, the current shield 126 is secured to the
backplate 122 via screws 156 (FIG. 6) passing through the
through-holes 150 (FIG. 6), along with other conventional mounting
hardware, including standoffs 158. An inner compartment 160 within
the outer compartment 154 is defined at least in part by the
interior surface 148 of the current shield 126, the interior
surface 128 of the backplate 122, and the front side 138 of the
printed circuit assembly 124. (The inner compartment 160 is also in
communication with the transformer compartment 168.)
With respect to normal underwater lighting operation, for purposes
of the present discussion, the underwater light assembly 110
functions in a manner similar to conventional underwater lights
equipped with printed circuit assemblies populated with LEDs as the
principle light emitters or lighting elements. However, the
underwater light assembly 110 further performs a stray electrical
current collection function, as described above with respect to the
underwater light assembly 10 of the embodiment of FIGS. 1 4. To the
extent stray electrical current enters flood water within the
transformer compartment 168, and flows therefrom into the inner
compartment 160 through the unsealed access hole 134, such stray
electrical current is still subject to collection in accordance
with the above-described stray electrical current collection
function of the underwater light assembly 110.
Referring again to FIG. 7, the base 170 is secured to a rear
surface 166 of the backplate 122 by appropriate conventional
hardware, and sealed thereagainst via a first O-ring 176. A largely
open region 178 exists between the base 170 and the backplate 122,
beneath the sealed connection between the base 170 and the
backplate 122, and has a function to be explained hereinafter. The
cover 172 is secured to the base 170 by appropriate conventional
hardware, is sealed thereagainst via a second O-ring 180, and is
electrically coupled to a path to ground via a grounding lug 182
(see also FIG. 5) mounted both to the cover 172 and the backplate
122. In this manner, the base 170 and the cover 172 form the
transformer compartment 168, the volume of which is physically
separated from that of the outer compartment 154, and the walls of
which are also physically separated from those of the outer
compartment 154. The function and significance of this separate
(and separated) compartment mounting arrangement with respect to
the transformer 130 and the printed circuit assembly 124 will now
be described in conjunction with FIG. 8, in which is illustrated
the underwater light assembly 110 assembled within an appropriate
wet niche 162, e.g., Hayward Pool Product's SP0601U wet niche.
Referring to FIG. 8, spa water flowing in and out of an inner
chamber 164 may be used to cool both the rear surface 166 of the
backplate 122 and all external surfaces of the transformer
compartment 168 (i.e., the external surfaces of the base 170 and
the cover 172, including those external surfaces of the backplate
122 and the base 170 adjacent the largely open region 178). Such
wet niches are often built into concrete spa walls, and their use
can be especially beneficial when, as in the present invention, the
underwater light employed is equipped with multiple high-intensity
LEDs requiring rapid rates of heat removal to remain within an
acceptable range of operating temperatures. In particular, it is
noted that the underwater light assembly 110 includes exterior
surfaces exposed to cooling spa water amounting to a significantly
higher total surface area than known spa lights for use in similar
applications. Specifically, the separate transformer compartment
168 is, by this expansion of spa-water cooled exterior surfaces,
equipped with an essentially separate cooling mechanism, such that
not only are the transformer compartment 168 and outer compartment
154 separately cooled, but they are essentially completely
thermally isolated. As such, any heat generated by the transformer
130 is essentially incapable of affecting the printed circuit
assembly 124, and vice versa. Since with respect to the present
underwater light assembly 110 both components will tend to run
quite hot, such thermal isolation is essential to ensuring all
hot-running components of the underwater light assembly 110 are
maintained within an acceptable range of operating
temperatures.
It should be appreciated that the underwater light assembly 110 of
the present invention provides numerous advantages over the prior
art discussed above. Since the underwater light assembly 110 is
equipped with a 120V A/C to 12V A/C transformer, it may be
conveniently coupled directly to standard 120V A/C power obtained
from a remote source to which multiple instances of the underwater
light assembly may be coupled in parallel. The underwater light
assembly 110 may be incorporated into the concrete wall of a
permanent (e.g., below ground) spa, as may other known spa lights,
but the underwater light assembly 110 provides the further
advantage of being simultaneously capable of producing its own DC
power from an external 120V A/C source, and producing white light
of exceptional brilliance/luminosity from multiple arrays of color
LEDs, without risk of overheating. At least one major hurdle to
this type of performance is cleared by the above-described separate
transformer compartment arrangement for maximizing spa water
cooling, e.g., in combination with similar backplate and lens
exterior-surface cooling.
It should be noted that the underwater light assembly 110 of the
present invention can have numerous modifications and variations.
For example, in particular spa lighting applications in which a
built-in transformer design is not required, the transformer 130
and the separate transformer compartment 168 can be removed from
the underwater light assembly 110 (i.e., similar to the underwater
light assembly 10 associated with the first embodiment of the
present invention, discussed above). In such applications, the
underwater light assembly 110 can be supplied with external 12V A/C
power (e.g., by the use of a conventional off-the-shelf 120V A/C to
12V A/C transformer mounted in a steel enclosure near the spa) for
later conversion to DC power.
It will be understood that the embodiments of the present invention
described herein are merely exemplary and that a person skilled in
the art may make many variations and modifications without
departing from the spirit and scope of the invention. For example,
the transformer 30 of the underwater light assembly 10 associated
with the above-discussed first embodiment for a pool lighting
application can be housed in a substantially separate
rearwardly-extending compartment (e.g., similarly to the
transformer 130 of underwater light assembly 110 associated with
the above-discussed second embodiment for a spa lighting
application). All such variations and modifications, including
those discussed above, are intended to be within the scope of the
invention as defined in the appended claims.
* * * * *
References