Horticulture light fixture having integrated lamp and ballast

A method for integrating at least one very high output (VHO) fluorescent lamp and at least one ballast within at least one fluorescent lamp fixture sealed from the growing environment is disclosed. The at least one ballast is secured within an upper fixture structure between a first cooling duct and a second cooling duct. At least one mid-plate reflector is mounted within the at least one upper fixture structure enclosing the at least one ballast thereby defining an upper chamber and a lower chamber. The at least one fluorescent lamp is installed in the lower chamber that is sealed from the growing environment by a transparent glass sheet, mounted to either or both the endplates or upper fixture structure. At least one fan is installed to the first cooling duct or the second cooling duct to provide the forced air cooling. The mid-plate reflector benefits from openings above the lamp location thereby providing a vent for heated air around the fluorescent lamp to rise up, away from the lamp, and out into the upper chamber where it is exhausted. The mid-plate reflector further benefits from being solid above the lamp ends or electrodes thereby retaining heat and improving lamp performance. At least one baffle located within the upper chamber directs cooling air provided by the fans through the mid-plate reflector to better cool the lamp, around the ballast to improve ballast cooling characteristics, or both.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates in general to horticultural and agricultural lighting systems used in developing and growing plants in controlled environments. More specifically, the present invention relates to a horticulture light fixture having an integrated very high output (VHO) fluorescent lamp and ballast.

2. Description of the Related Art

Indoor gardens, green houses, hydroponics systems, and isolated carbon dioxide growing chambers all require light to grow plants. Currently, the most common grow-light source is HID (High Intensity Discharge) lamps constructed from high pressure sodium and metal halide technologies. The HID lamps have been a mainstay in the indoor gardening market for over 20 years, but technology advancements in fluorescent lamps and the ballasts that power the same now produce efficient lumens in adequate quantity to viably grow plants that before only could be grown by HID lamps at much lower power efficiencies.

Attenuation of light is a major issue faced by plant growers around the world. Plant growers prefer to position the light fixture close and above the growing plants in order to limit the effects of attenuation. Attenuation is the gradual loss in intensity of any kind of flux through a medium. For instance, sunlight is attenuated by atmosphere, and X-rays are attenuated by lead. In either example, the “distance” the flux must travel through the medium directly impacts the loss of intensity. Therefore it follows that the greater the distance between the lamp and the plants, the more lumens lost in the atmosphere in between. In short, the user of a grow light fixture desires a location of the fixture as close to the plants as possible, without causing heat impact on the plants that will stunt development, cause curl, or kill the plant.

Heat produced by the light fixture is always a design challenge and concern. The HID lamps by consequence of high lumen output with low power efficiencies produce undesirable amounts of heat. The thermal pollution or heat generated must then be isolated and removed from the growing environment. In order to combat the negative effects of heat, light fixtures with various active cooling systems were developed. These cooling systems rely upon a fan or fans, pushing or pulling isolated cooling atmosphere through the fixture, and the heated atmosphere out of the fixture away from plants. [See U.S. Application 2008/025071 Townsley] The fixture may be placed close to growing plants without worry of plant harm due to excessive temperatures.

Many attempts have been made for manufacturing grow light fixtures adapted for combating the negative effects of heat, while still benefitting from the simplicity of having the ballast integrated within the light fixture. [See U.S. Pat. No. 7,524,090 Hargreaves] Integrating a ballast within the fixture for easy install has been accomplished for HID by force cooling fans, and isolating the ballast with an air gap. Fluorescents up until recently, did not produce the quantity of lumens required to grow plants through the flowing and fruiting phase, leaving HID lamps as the first choice as a yield grow light. Also, the lower lumen output T-5 lamps did not generate enough heat to cause premature failure of the ballast when integrated within the fixture, so passive cooling with vents was enough. The new and recently developed higher lumen output linear T-5 lamps referred to as Very High Output (VHO) creates new design challenges in integrating the ballast within the fixture. The VHO lamps show potential to replace the HID lamps as the standard for the industry.

HID has been the market standard for high lumen output for yielding plants, and the forced air cooling feature is well known in this art. Fluorescents have been a market standard for starting plants or developing plants, leaving the flowering and fruiting yields to the HID. Prior to reaching new levels of lumen output, most fluorescent fixtures were passively cooled, and the ballast for powering the fluorescent lamps were in most applications easily located within the fixture without concern of premature failure due to heat soaking. With the new VHO lamp development, the VHO fluorescent lamps can produce lumens in quantity matching HIDs, at a greater lumen per electrical watt efficiency. This new VHO increase in lumen power, comes substantial heat production increase, and thermal problems when attempting to integrate the ballast within the fixture.

To further compound the issue, the power requirements of the VHO lamp is more than the old fluorescent T-5 lamp, thereby requiring more power from the ballast, thereby increasing the heat generated by the ballast. The increase lamp temperatures coupled with the increased ballast temperatures require a fan or forced air cooling system to remove the excess heat. But just removing the heat is not enough, the fluorescent lamps benefit from a cooled center section, while further benefitting from warmer lamp ends. In short, the fixture must be forced air cooled, each lamp cooled in the middle, kept heated on the ends, the heat sealed from the growing environment while maintaining the ballast within operating temperatures.

Fluorescent lamps, especially the smaller T-5 tubes such as the VHO lamps, require optimum temperatures in order to produce maximum lumens, and operate at maximum life expectancy. Lumen output depends on two variable temperatures, a first temperature immediately around the body of the linear lamp, and a “cold” spot temperature of the lamp at the electrodes or ends. A first temperature around 95 degrees Fahrenheit maximizes lumen production of the T-5 bulb. However, the ends or cold spots located around the electrode require a higher temperature, around 110 to 115 degrees Fahrenheit for maximum performance. Not only do the lamps need to be cooled in the middle, along body of the lamp, but the ends or electrodes require increased temperatures in order to perform optimally.

Some other light fixtures utilize simple methods to raise the temperature of the cold spots on fluorescent bulbs involving cylindrical sleeves attached around the ends or electrodes covering the cold spots. [See U.S. Patent Application 2006/0055293 Ngai] The method of sleeving or insulating the lamp ends require additional hardware and maintenance. Each time a lamp is replaced, a sleeve must be installed increasing expense and complexity.

The new VHO lamps require a fixture able to maximize performance of the lamps by regulating their temperature, while preventing premature thermal failure of the ballast.

SUMMARY OF THE INVENTION

To minimize the limitations found in the prior art, and to minimize other limitations that will be apparent upon the reading of the specifications, the present invention provides a method for integrating very high output (VHO) fluorescent lamps and ballast within a grow lamp fixture benefitting from forced air cooling. The ballast is secured within an upper fixture structure between a first cooling duct and a second cooling duct. The fixation to the upper structure may be further enhanced with heat conducting medium or grease between the ballast and upper fixture structure. At least one mid-plate reflector is mounted within an upper fixture structure enclosing the ballast thereby defining an upper chamber and a lower chamber. The first and second cooling ducts are in flow communication through the upper chamber. The fluorescent lamps are located within the lower chamber. In the preferred embodiment, the at least one mid-plate reflector has a plurality of longitudinal slot openings above the lamp body, allowing air flow communication between the lower chamber and the upper chamber. The slot openings are of adequate size to allow heated air created by the fluorescent lamp to rise through the mid-plate reflector and into the upper chamber where it is exhausted. At least one transparent glass sheet is sealingly mounted to the lower fixture structure enclosing the at least one fluorescent lamp. Forced air cooling is performed by at least one fan installed to either the first or second cooling duct, or if multiple fans are used to both.

To further enhance VHO lamp performance, a method for increasing the temperature of the cold spots at the lamp ends or electrodes employed wherein the mid-plate reflector is left solid above the lamp ends or electrodes. Practice teaches that having the mid-plate reflector solid over the lamp end or electrode while having slot openings over the remainder of the lamp helps keep the lamp body at optimum temperatures, while increasing the temperature at the lamp end or electrode. The number of lamps, the forced cooling air volume and temperature, the type of ballast, all play factors in determining how much of the mid-plate reflector is kept solid, and how much is punched out with openings. Practice teaches that leaving 1.0 to 3.0 inches solid at the ends of the mid-plate reflector is enough to increase the temperature to optimum levels at the lamp ends or electrodes under most circumstances.

To further control the operating temperature at the ballast, lamp body, and the lamp ends or electrodes, a baffle is located within the upper chamber. There can be more than one baffle, depending on desired temperatures. The baffle is positioned and located to force more cooling air to the location where temperature decrease is desired. If the lamp body is running above optimum temperatures, the baffle is shaped and formed to redirect the cooling air flowing through the upper chamber, and located to direct more of the cooling air stream through the openings in the reflector, thereby increasing cooling potential at the lamp. If the ballast is suffering from premature failure, the baffle may be positioned to force more cooling air around the ballast thereby isolating the ballast from the heated air rising off of the lamp or lamps.

OBJECTS AND ADVANTAGES

The primary object of the invention is to provide the first grow light fixture that successfully utilizes the new VHO lamp technology.

One object of the invention is to provide an easy to install horticulture light fixture having integrated at least one very high output (VHO) fluorescent lamp and at least one ballast into a single fixture.

Another advantage of the invention is to provide a horticulture light fixture that is constructed and arranged whereby the at least one ballast is maintained at optimum temperatures.

Another objective of the invention is to provide a horticulture light fixture utilizing at least one fan to push or pull cooling air through the at least one fixture thereby maintaining performance temperatures at the fluorescent lamp and ballast. The fan or fans may either be located at the first or second cooling duct, or both.

Another objective of the invention is to provide a horticulture light fixture that isolates the heated atmosphere from the growing environment.

Yet another objective of the invention is to provide a horticulture light fixture including at least one baffle for controlling the velocity and direction of the cooling atmosphere within the fixture, thereby maintaining desired performance temperatures of the lamp, lamp body, and lamp ends or electrodes.

Yet another advantage of the invention is to provide a horticulture light fixture that does not require an internally sealed wall that controls the cooling air, and instead relies upon a baffle that allows cooling air to pass around and by thereby providing a controlled cooling of the ballast and controlled cooling of the lamp.

A further object of the invention is to provide a horticulture light fixture having a mid-plate reflector that benefits from a plurality of longitudinal slots running parallel and above the at least one fluorescent lamp whereby the plurality of longitudinal slots provide cooling to the center body of the lamp.

A further advantage of the invention is to provide a horticulture light fixture having a mid-plate reflector that benefits from being solid without slots above the lamp end or electrodes, thereby retaining the heated air around the lamp ends or electrodes of the fluorescent lamp.

The final object of the invention is to provide a grow light fixture utilizing new fluorescent technologies having a greater lumen per electrical watt efficiency than standard HID lamps.

These and other advantages and features of the present invention are described with specificity so as to make the present invention understandable to one of ordinary skill in the art.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following discussion that addresses a number of embodiments and applications of the present invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and changes may be made without departing from the scope of the present invention.

FIG. 1is an exploded view of the preferred embodiment of a horticulture light fixture10having integrated very high output (VHO) fluorescent lamp22and at least one ballast23. A method for integrating the at least one ballast23within the at least one very high output (VHO) fluorescent lamp fixture10includes securing the at least one ballast23to the upper structure14at securing through holes23a, between a first cooling duct32alocated through upper structure14at first hole30a, and a second cooling duct32blocated through the upper structure14at second hole30b. Mounting the mid-plate reflector20to the upper structure14, via end plates16thereby defining a floor of an upper chamber20aand a ceiling of a lower chamber20b. The end plates16having through holes16afurther work in mechanical communication with hangers28for easy vertical securing. Installing at least one fluorescent lamp22in the lower chamber20bsecured in lamp sockets26and finally sealing the growing environment24bfrom the at least one lamp22by defining the floor of the lower chamber24aand the growing environment24b, by sealingly securing at least one transparent glass sheet24to the end plates16, or the upper structure14, or in securing combination to both the end plates16and the upper structure14.

One skilled in the art understands the common electrical connections required in bringing in power34into the fixture, to the ballast23, the fan11in FIG.2., to the lamp sockets26, finally to the lamp22.

The preferred method includes a plurality of openings that inFIG. 1. are longitudinal slots20cthrough the mid-plate reflector20running parallel with the lamp22. The plurality of longitudinal slots20chave adequate size to allow the heated air created by the lamp22to rise through the mid-plate reflector20and into the upper chamber20awhere it is exhausted out. The openings or longitudinal slots20callow flow communication between the upper chamber20aand the lower chamber20b.

As shown inFIG. 1. The longitudinal slots20care not located above the lamp ends or electrodes22ain the shown embodiment. The method teaches a solution to cold spots at the end of the lamps by creating heat retention around the lamp ends or electrodes22a. Without a longitudinal slot20cabove the lamp end or electrode22a, the heated air has no opening to rise up and through the mid-plate reflector20and into the upper chamber20a. The desired temperature for the lamp end or electrode22a, can be regulated by the location, size, solid portion20d, and quantity of longitudinal slots20c. The solid portion20dis located above the lamp end or electrode22athereby increasing the operating temperature and helping performance. The size of the solid portion20dis tuned or changed to match the temperature requirements at the end of the lamp or electrode22a. For example, a four VHO lamp fixture would require less solid portion20dthen a two VHO lamp fixture as there is more heat generated and retained in the lower chamber if the forced cooling air system was the same. In colder applications the solid portion20dis increased, in warmer applications it is decreased.

The location of a baffle50is also important to cooling within the fixture. The baffle50can be sized and positioned to maximize the cooling effects within the fixture10. The baffle50can be shaped, formed, and located to force more cooling air through the mid-plate reflector20thereby decreasing the temperature of the lamp22. The advantage of having the longitudinal slots20conly over the lamp22potion that requires additional cooling centers on the baffle50being able to direct more air through the longitudinal slots20cwhile avoiding an increase of cooling air directed at the lamp end or electrode22a. Keeping the ends of the lamp22aheated to optimal performance while still being able to cool the center of the lamp22to enhance longevity and lumen output is a difficult thermal management challenge made simple by longitudinal slots20c. In applications where additional cooling at the center of the lamp22is required, the baffle50is added either one or a plurality, to direct the cooling air and control the temperature of the lamps22. If the lamps22are operating at optimal temperatures without the need to direct additional cooling air, the baffle50may also be used to direct additional air at the ballast23, or in instances where it is desirable to increase velocity while decreasing volume of flow, the baffle50can be used to regulate the cooling air flow characteristics within the fixture10. The baffle50may be fixated to the mid-plate reflector20or upper fixture structure14with high heat adhesive, pop rivet, epoxy, or suitable double sided tape.

At least one baffle50may be integrated as a structural feature in the upper fixture structure14, the ballast23, or the mid-plate reflector20. The different functional shapes, sizes, and mounting locations within the upper fixture structure20aare as many as there are desired thermal conditions within the horticulture fixture10.

As the preferred embodiment shows in FIG.2., the first cooling duct32a, upper chamber20a, and second cooling duct32bare all in air flow communication with the fan11. The method benefits from forced air cooling having fan11increase air flow and pressure through conduit40a, into and through first cooling duct32a, into and through the horticulture light fixture10within the upper chamber22a, but sealed away from the growing environment24bby the glass sheet24, exhausted through the second cooling duct32band out through second conduit40b, from there the heated air can be exhausted into a desired location.

FIG. 3shows the Horticulture Light Fixture10having a cut-away, with arrows depicting motion demonstrating internal air flow49that after impacting baffle50, became disrupted air49ahaving change in direction, velocity, or pressure from the initial air flow49. Desired changes in cooling conditions of the horticultural light fixture10and it's internal components shown inFIG. 1, can be temperature tuned-in or maximized by making changes to baffle50configuration and location. One or more baffles50secured to the upper structure14or to the mid-plate reflector20, installed within the internal air flow49within the upper chamber20amay either force more cooling air through the longitudinal slots20cthereby increasing cooling flow at the lamp22, or force air up and at the upper structure14thereby increasing cooling flow at the ballast23shown in exploded viewFIG. 1. The baffles'50size, quantity, shape, and location within the internal air flow49within the upper chamber20a, all contribute in controlling the cooling characteristics of the device. If for example the ballast23is suffering from too high of operating temperature, then baffle50is installed to direct more cooling air at the ballast23. In another example if the lamps22were operating over ideal temperatures then a large baffle50installed to direct more cooling air through the mid-plate reflector20, even directing a majority of the cooling air through the mid-plate reflector20under the baffle50thereby decreasing temperatures at the lamps22, and allowing the now heated air to pass through the mid-plate reflector20behind the baffle50and out the second cooling duct32b. Many optional placements of baffles50within the internal air flow49are available to one of ordinary skill to maximize the performance of the Horticulture Light Fixture10.

FIG. 4is a perspective bottom view of the horticulture light fixture10with the transparent glass sheet24connected on one side to the upper structure14. When in the closed position, the transparent glass sheet24defines the floor of the lower chamber20b. The sockets26mount to the endplates16then the lamps22install into the sockets26.

FIG. 5shows an operational flow chart of a method for integrating at least one ballast within at least one very high output (VHO) fluorescent lamp fixture60. The method is initiated as at block62by securing the at least one ballast within an upper fixture structure between a first cooling duct and a second cooling duct. The upper structure provides a secure location while having an added benefit of thermally heat sinking the ballast to the upper structure, thereby providing both conduction cooling and convection air cooling. Mounting at least one mid-plate reflector within the at least one upper fixture structure via endplates, thereby defining a floor of an upper chamber and a ceiling of a lower chamber64, enclosing the at least one ballast.

Then, as shown at block66, sockets are mounted to the endplates, and at least one fluorescent lamp is installed in the at least one lower chamber. Thereafter, at least one transparent glass sheet is sealingly mounted to at least one lower fixture structure enclosing the at least one fluorescent lamp as shown at block68. Block70indicates installing at least one fan to the first cooling duct in flow communication with the second cooling duct.

FIG. 6shows an operational flow chart of a method for integrating the at least one ballast within the at least one fluorescent lamp fixture having a plurality of cold spots at a first end and a second end of at least one fluorescent lamp and a plurality of hot spots at a lamp body80. The method is initiated by securing at least one ballast within at least one upper fixture structure between a first cooling duct and a second cooling duct as shown in block82. Looking to block84, construction of a mid-plate reflector having openings over the portion of the fluorescent lamp locations that require cooling, and solid over fluorescent lamp locations that require higher temperatures. Then, mounting at least one mid-plate reflector within the at least one upper fixture structure enclosing the at least one ballast as shown at block85. As shown at block86, the fluorescent lamps are enclosed in the lower fixture structure sealed from the growing environment via glass sheet or other transparent sheet. Finally, as shown in block88, at least one fan may be installed to the first cooling duct in flow communication with the second cooling duct.

While the present invention has been described in terms of specific embodiments, it is to be understood that the invention is not limited to the embodiments set forth herein. The foregoing description of the preferred embodiment of the present invention has been presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teachings. It is intended that the scope of the present invention not be limited by this detailed description, but by the claims and the equivalents to the claims appended hereto.