Modular in-grade fixture with heat pipes
11248760 · 2022-02-15
Inventors
Cpc classification
F21V23/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V5/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V29/51
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V14/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21Y2115/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S8/022
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F21V5/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V29/73
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S8/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
The disclosure described herein is directed to an in-grade lighting fixture with improved heat dissipation that provides greater flexibility in servicing, replacing, or installing internal components within the fixture. The in-grade lighting fixture comprises features to assist in dissipating heat generated by light sources, such as LEDs, and/or other electronic components to optimize performance and allow for increased output power for the light sources. The disclosure uses a heat sink assembly that is in thermal communication with the in-grade lighting fixture in order to dissipate heat within the lighting fixture out to the ambient, which optimizes performance and allows for increased output power for the light source.
Claims
1. An in-grade lighting fixture, comprising: a fixture housing comprising an optical chamber in said fixture housing, said optical chamber comprising: at least one light source; and a heat sink assembly, wherein said at least one light source is in thermal communication with said heat sink and emits light out a top opening of said fixture housing; wherein said heat sink assembly is in thermal communication with least one inner surface of said upper portion of said fixture housing establishing a thermal path between said at least one light source and said fixture housing; wherein said heat sink assembly arranged to pivot within said optical chamber to adjust the direction of light emission from said at least one light source.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
DETAILED DESCRIPTION
(12) The disclosure described herein is directed to different aspects of an in-grade lighting fixture with improved heat dissipation. The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. It will be apparent, however, to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts. As described herein, the use of the term “and/or” is intended to represent an “inclusive OR”, and the use of the term “or” is intended to represent an “exclusive OR”.
(13) The disclosure uses a heat sink assembly that is in thermal communication with the in-grade lighting fixture in order to dissipate heat within the lighting fixture out to the ambient. The heat sink assembly is configured to receive a light source, such that the light source emits light out of the lighting fixture in response to a bias. The heat sink assembly can also be configured to allow for the light emission of the light source to be adjusted and/or modified from within the in-grade lighting fixture without having to remove the lighting fixture. The in-grade lighting fixture provides greater flexibility in servicing, replacing, and/or installing internal components within the fixture. As further described below, the fixture 100 has features to assist in dissipating heat generated by the light source, such as but not limited to LEDs, to optimize performance and allow for increased output power for the light source.
(14) The disclosure is described herein with reference to certain aspects, but it is understood that the disclosure can be embodied in many different forms and should not be construed as limited to the aspects set forth herein. In particular, the disclosure is described herein in regards to an in-grade lighting fixture with improved heat dissipation, but it is understood that the disclosure can be utilized in many different types of lighting fixtures and is not limited to in-grade lighting fixtures.
(15) Although the terms first, second, etc. may be used herein to describe various elements or components, these elements or components should not be limited by these terms. These terms are only used to distinguish one element or component from another. Thus, a first element discussed herein could be termed a second element without departing from the teachings of the present application. It is understood that actual systems or fixtures embodying the disclosure can be arranged in many different ways with many more features and elements beyond what is shown in the figures.
(16) It is to be understood that when an element or component is referred to as being “on” another element or component, it can be directly on the other element or intervening elements may also be present. Furthermore, relative terms such as “between”, “within”, “below”, and similar terms, may be used herein to describe a relationship of one element or component to another. It is understood that these terms are intended to encompass different orientations of the disclosure in addition to the orientation depicted in the figures.
(17) Aspects of the disclosure are described herein with reference to illustrations that are schematic illustrations. As such, the actual thickness of elements can be different, and variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances are expected. Thus, the elements illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region of a device and are not intended to limit the scope of the disclosure.
(18)
(19) The in-grade lighting fixture 100 comprises a generally cylindrical fixture housing 104 comprising an optical chamber 106 in an upper portion 108 of the housing, and electronic components 110 in a lower portion 112 of the housing. The optical chamber 106 comprises a light source 114 and a heat sink assembly 400. The light source 114 is mounted on the heat sink assembly 400 and emits light out a top opening 116 of the upper portion 108 of the housing 104 when power is applied to the light source 114. In one aspect, the light source 114 can be comprised of at least one LED. However, in other aspects, the light source 114 can comprise many different types of light sources, such as but not limited to lasers, fluorescent lights, etc., each of which can be arranged in many different ways within the optical chamber 106. The heat sink assembly 400 is disposed within the upper portion 108 of the housing 104, such that the heat sink assembly 400 is in thermal communication with at least the upper portion 108 of the housing 104.
(20) With reference to
(21) When the optical chamber 106 is installed within the fixture 100 and the faceplate 102 is mounted over the top opening 116 of the upper portion 108 of the housing 104, a seal is created between the faceplate 102 and the upper portion 108 of the housing 104 such that the optical chamber 106 is sealed from the ambient. The fixture 100 is further configured to allow air within the housing 104 to pass out of the optical chamber 106 when pressure builds up in the chamber 106, and to block ambient air from returning into the optical chamber 106. The fixture 100 can comprise a valve 302, as shown in
(22) During operation of the fixture 100, air within the upper and lower portions 108, 112 of the fixture housing 104 can be heated, which causes the air to expand and increases the air pressure within the upper and lower portions 108, 112 of the fixture housing 104. The valve 302 allows air to exit as the air pressure increases. When the fixture 100 is not in operation, air within the upper and lower portions 108, 112 of the housing 104 cools, but air is prevented from entering the fixture housing 104 due to the valve 302. This results in the formation of a negative air pressure, or vacuum, within the upper and lower portions 108, 112 of the fixture housing 104, and prevents condensation within the optical chamber 106, upper portion 108 and/or lower portion 112. The fixture 100 can have one or more valves 302 within the optical chamber 106, upper portion 108 and/or lower portion 112 of the fixture housing 104 that operate in conjunction with or independent from each other. The faceplate 102 is removably coupled to the upper portion 108 of the fixture housing 104. The faceplate 102 being removable allows the optical chamber 106 to be easily accessible. Removal of the faceplate 102 breaks the seal between the faceplate and the fixture housing 104 and allows air to enter into the fixture 100. However, once the newly entered air becomes heated and the air pressure within the fixture housing 104 increases, the air that entered due to the removal of the faceplate 102 exits out the fixture 100 through the valve 302. The negative air pressure, or vacuum, within the fixture 100 is thereby restored.
(23) The electronic components 110, such as but not limited to a ballast, can be housed within the lower portion 112 of the housing 104. The electronic components 110 are configured to provide sufficient voltage to the light source 114 and regulate the current provided to the light source 114. Power is supplied to the electronic components 110 from an external power source and the power for operating the light source 114 and electronic components 110 is typically provided by wiring contained in an outer protective conduit line that attaches to the lower portion 112 of the housing 104, which is known in the art. The electronic components 110 provide a wiring compartment, which is accessible from within the fixture 100, for wiring the light fixture to the external power source. The electronic components 110 provide electrical conductors that couple to the light source 114 within the upper portion 108, in order to provide power to the light source 114.
(24)
(25) In one aspect of the disclosure, the heat sink assembly 400 is a passive cooling system that is configured to dissipate heat within the fixture housing 104 to the ambient. In one aspect, the heat sink assembly 400 is disposed within the upper portion 108 of the fixture housing 104 and is in thermal communication with at least one inner surface of the upper portion 108 of the fixture housing 104. The heat sink assembly 400 transfers heat flux generated by the light source 114 away from the light source 114 and into a cooler condensing unit of the heat sink assembly 400. The heat flux is thereby transferred from the heat sink assembly 400 to the upper portion 108 of the fixture housing 104 and is dissipated to the ambient. The heat sink assembly 400 dissipates heat from the light source 114 such that the operational temperature of the light source 114 and/or the temperature within the fixture housing 104 does not exceed the temperature threshold for the light source 114 used. The temperature threshold is determined by the manufacturer of the light source 114 and in some aspects can range from 90° C. to 105° C., for example, while other light sources 114 can have a temperature threshold range that is lesser or greater.
(26) In some aspects, the heat sink assembly 400 can comprise one or more LEDs mounted on a heat sink 416 and one or more heat pipes 420, wherein the one or more heat pipes 420 are in thermal communication with the heat sink 416 and the fixture housing 104, such that heat generated from the LEDs is dissipated to the ambient. The upper portion 108 and lower portion 112 of the fixture housing 104 can be comprised of thermally conductive materials such that the fixture housing 104 assists in the dissipation of heat. This arrangement allows for the LEDs to operate at a lower temperature. In addition, a thermally conductive housing 104 could eliminate the need of an active cooling system, thereby reducing manufacturing costs. The heat sink assembly 400 being in thermal communication with the fixture housing 104 allows the one or more LEDs to be driven at an increased output power to produce a higher luminous flux while maintaining the operational temperature of the LEDs below the temperature threshold.
(27) Heat pipes are generally known in the art and are only briefly discussed herein. Heat pipes can comprise a heat-transfer device that combines the principles of both thermal conductivity and phase transition to efficiently manage the transfer of heat between two interfaces. At the hot interface within a heat pipe, a liquid in contact with a thermally conductive solid surface turns into a vapor by absorbing heat from that surface. The vapor condenses back into a liquid at the cold interface, releasing the latent heat. The liquid then returns to the hot interface through either capillary action or gravity action where it evaporates once more and repeats the cycle. In addition, the internal pressure of the heat pipe can be set or adjusted to facilitate the phase change depending on the demands of the working conditions of the thermally managed system.
(28) A typical heat pipe is comprised of a sealed pipe or tube made of a material with high thermal conductivity, such as copper or aluminum at least at both the hot and cold ends. A vacuum pump can be used to remove air from the empty heat pipe, and the pipe can then be filled with a volume of working fluid (or coolant) chosen to match the operating temperature. Examples of such fluids include water, ethanol, acetone, sodium, or mercury. Due to the partial vacuum that can be near or below the vapor pressure of the fluid, some of the fluid can be in the liquid phase and some will be in the gas phase.
(29) The heat sink assembly 400 comprises an upper body 412, a lower body 414, a heat sink 416, at least one clamp 418, and at least one heat pipe 420, wherein the at least one heat pipe 420 is in thermal communication with the heat sink and the upper body.
(30) The heat sink 416 comprises a top mount surface 417, a bottom surface (not shown), and a plurality of side surfaces 419, wherein the side surfaces 419 are interposed between the top mount surface 417 and the bottom surface. The top mount surface 417 of the heat sink 416 is configured to receive a light source, and at least one heat sink extension 426 extends from at least one of said plurality of side surfaces 419. In the aspect of the heat sink 416 shown in
(31) The at least one clamp 418 comprises a clamp opening 428, a heat pipe opening 430, a clamp slot 432, and a clamp screw opening 434. The clamp opening 428 receives the at least one heat sink extension 426 in order to thermally couple the heat sink 416 and the clamp 418. The clamp 418 is comprised of thermally conductive materials and assists in dissipating heat from the heat sink 416. In the aspect of
(32) The clamp slot 432 is a narrow opening that extends through part of the clamp opening 428. The clamp slot 432 allows the clamp 418 to partially increase the size of the clamp opening 428 in order to receive the heat sink extension 426. Partially increasing the size of the clamp opening 428 allows the heat sink extension 426 to be easily received by the clamp opening 428, especially in instances where the clamp opening 428 and heat sink extension 426 have substantially similar dimensions. The clamp screw opening 434 extends into the clamp 418 from an upper surface of the clamp 418 to a distance beyond the clamp slot 432. A clamp screw 422 can be threadedly received by the clamp screw opening 434 such that the clamp screw 422 pulls the portions of the clamp below and above the clamp slot 432 together as the clamp screw is threaded into the clamp screw opening, thereby tightening the clamp opening 428 around the heat sink extension 426. This firmly couples the clamp 418 and heat sink 416 together, and also forms a thermal path between the heat sink 416 and the clamp 418.
(33) The clamp 418 is further configured to receive the heat pipe 420. The clamp 418 comprises a heat pipe opening 430 that receives the heat pipe 420 in order to form a thermal connection between the heat pipe 420 and the heat sink 416. The heat pipe opening 430 is an aperture that extends into the clamp 418 and allows at least part of the heat pipe 420 to be inserted into the heat pipe opening 430 to thermally couple the heat pipe 420 and the clamp 418. In some aspects, the heat pipe opening 430 can be correspondingly shaped to the heat pipe 420, but in other aspects, the heat pipe opening 430 can have a different shape than the heat pipe 420. The heat pipe 420 can be bonded to the clamp 418 by using thermal epoxy or the like, such that at least part of the heat pipe 420 is bonded to the clamp 418 within the heat pipe opening 430. The thermal epoxy can also form a seal between the heat pipe 420 and the heat pipe opening 430.
(34) The upper body 412 is configured to be thermally coupled to the heat pipe 420, such that the upper body 412 is in thermal communication with the heat sink 416. In one aspect, as shown in
(35) As shown in
(36) The at least one channel 440 extends from the corresponding window 442 into the cylindrical body 441 of the upper body 412 and allows part of the heat pipe 420 to be inserted into the at least one channel 440. In some aspects, the at least one channel 440 can be correspondingly shaped to the heat pipe 420. However, in other aspects, the at least one channel can have a shape that is different than the heat pipe. The heat pipe 420 can be bonded to the upper body 412 by using thermal epoxy or the like, wherein the thermal epoxy bonds the heat pipe to the at least one channel 440. The thermal epoxy also seals the heat pipe 420 within the upper body 412. The at least one channel 440 can be arranged in many different configurations. In some aspects, the at least one channel 440 partially extends into the upper body 412 from the window 442. In other aspects, the at least one channel 440 extends into the upper body 412 from the window 442 to an upper surface 446 of the upper body 412 opposite the window 442. In such aspects, as shown in
(37) With reference to
(38) In the aspect of
(39) At least one advantage of the disclosure, is that the heat sink 416 can pivot about the first and second heat sink extensions 426 to adjust the light emission of the light source mounted on the heat sink 416. The respective clamp screws 422 of the first and second clamps 418 can be partially unthreaded from each of the clamp screw opening 434 thereby loosening the connection of each clamp opening 428 around the first and second heat sink extensions 426. The heat sink 416 can then be rotated about the first and second heat sink extensions 426 to a desired angle. After the heat sink 416 has been adjusted to the desired angle, the clamp screws 422 of the first and second clamps 418 can be threaded to tighten the respective clamp openings 428 around the first and second heat sink extensions 426. Pivoting the heat sink about the heat sink extensions allows the light source to be adjusted after the fixture 100 has been installed without having to demolish the surrounding hardscape and uninstall the entire in-grade lighting fixture. Yet another advantage of the disclosure is that pivoting the heat sink can also compensate for fixtures that were not properly installed and/or have shifted over time. The heat sink being pivotable about the heat sink extensions is not limited to the aspect of
(40) With reference to
(41) An advantage of the disclosure is that the heat sink assembly 400 is arranged to allow for 360° rotation of the heat sink assembly 400 within the upper portion 108 of the fixture housing 100, thereby allowing the optical orientation to be set to a desired orientation. Rotating the heat sink assembly 400 within the fixture housing also allows for further customization of the light emission of the light source. When the light source is mounted on the heat sink 416 and is operating, the heat sink assembly 400 utilizes the heat pipes 420 that accelerate the heat transfer away from the light source with pure conduction to the exterior of the fixture housing 100 without compromising lumen output. The heat sink assembly 400 ensures longer extended lifetime performance of the light source. The disclosure provides heat dissipation through the heat pipes and through the fixture housing to the ambient. Yet another advantage of the disclosure is that the heat sink assembly 400 is easily removable from the fixture 100, such that the light source, driver and/or other electronic components within the fixture 100 can be easily accessed, serviced and/or replaced.
(42) In one aspect, as shown in
(43)
(44) Yet another advantage of the disclosure is that the heat sink assembly 400 can be used as a retrofit kit assembly for existing light fixtures. The heat sink assembly 400 installed in existing light fixtures provides improved heat dissipation, which in turns allows higher output light sources to be used in existing light fixtures. The heat sink assembly 400 allows existing light fixtures to be upgraded without having to remove the existing light fixture. Some existing light fixtures are installed in soil, concrete, asphalt and other hard surfaces that could require significant labor, time and expense to dig out and remove the existing light fixture. Installation of the heat sink assembly 400 in existing light fixtures would typically only require the removal of the faceplate and the existing light source. In some instances the existing electronic components that provided power to the existing light source could be used with the heat sink assembly 400.
(45) The heat sink assembly can be configured in many different ways and is not intended to be limited to the aspects presented herein. For example, the heat sink assembly can comprise a plurality of heat pipes and a plurality of clamps, or each clamp can comprise a plurality of heat pipes. Furthermore, the heat sink assembly can be scaled up for larger fixtures using higher heat fluxes.
(46) The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.