Radiant energy – Radiant energy generation and sources – With radiation modifying member
Reexamination Certificate
2003-07-07
2004-10-26
Nguyen, Kiet T. (Department: 2881)
Radiant energy
Radiant energy generation and sources
With radiation modifying member
C250S455110
Reexamination Certificate
active
06809326
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultraviolet (hereinafter “UV”) light apparatus, module and system for the treatment of air which, upon exposure to UV light, will destroy harmful bacteria, micro-organisms and/or offensive and noxious odors in the air contained within a confined space or in air passing through a confined space such as a conduit or a heating/ventilation air conditioning (hereinafter “HVAC”) duct.
BACKGROUND ART OF THE INVENTION
UV light sources for the treatment of air typically take the form of a UV lamp positioned within a confined space such as the cross-sectional area of a conduit, for example, in a HVAC duct located in the home or an office building. UV lamps, such as those disclosed in U.S. Pat. No. 5,751,007 issued May 12, 1998, are known to emit UV light through two different types of tubing contained in the lamp, thereby generating UV light at different radiation wavelengths for destroying harmful bacteria and for the production of ozone to remove offensive and noxious odors. According to the disclosure of this patent, one kind of tubing will transmit light at wavelengths over the full radiation spectrum of UV light (what the patent refers to as UVA and UVB light), and the other tubing will transmit light at wavelengths only above 200 nanometers (defined in the patent as UVA light). The patent refers to UVA light as that light which is transmitted at wavelengths above 200 nanometers, and UVB light as that light which is transmitted at radiation wavelengths below 200 nanometers. However, according to a Microsoft Encarta Online Encyclopedia article entitled “Ultraviolet Light” by Thomas W. Davis, M.S., Ph.D. (published by the Microsoft Corporation, 2000), UV light is often divided into three different wavelength categories: UVA, UVB and UVC. In general, the shorter wavelengths of UV radiation are more dangerous to living organisms. Thus, UVA light has a wavelength from about 400 to about 315 nanometers; UVB light occurs at wavelengths from about 315 to about 280 nanometers, which causes sunburn and can cause skin cancer upon prolonged exposure; and UVC light has radiation wavelengths of approximately 290 to 15 nanometers which is often used to sterilize surfaces because of its germicidal activity against bacteria, viruses and micro-organisms. The “Oxford Dictionary Of Science,” on the other hand, classifies ultraviolet light ranges according to its effects on the human skin, as UV-A (320-400 nm), UV-B (290-320), and UV-C (230-290 nm). And according to U.S. Pat. No. 4,967,090 issued Oct. 30, 1990, the U.S. FDA (Food and Drug Administration) defines UVA as the region of 320-400 nm and UVB as the region of 260-320 nm. In view of the foregoing discrepancies, and for the purposes of describing the invention herein, the term UVC shall refer to that ultraviolet light which occurs in the range of from about 15 to about 290 nanometers. Nonetheless, tubing consisting of special formula glass may be designed to be transparent to the longer UV wavelengths, while the use of pure quartz tubing is transparent to the entire, naturally occurring range of UV light, including ultraviolet ranges below 200 nm.
Within the UVC range of ultraviolet light as defined above, maximum germicidal activity is recognized to occur at a radiation wavelength of about 253.7 nanometers. As indicated above, germicidal activity alone (without the production of ozone) can be effected by the use of specially prepared quartz tubing for the UV lamp that is commonly referred to in the industry as L-quartz, which is quartz doped with titanium dioxide. However, when UVC light interacts with the oxygen in the ambient atmosphere at a radiation wavelength of approximately 185 nanometers, maximum ozone generation and output occurs. The production of ozone at this wavelength helps to reduce or substantially eliminate offensive and/or noxious odors that occur within the air, such as in air conditioning ducts in the home or office buildings when no fresh air is being introduced into the system. This condition generally occurs when air is being constantly re-circulated through a HVAC system under circumstances when minimal amounts of fresh air are introduced into the system, typically during cold weather conditions in order to conserve heat and reduce energy consumption.
As indicated above, ozone production from a UV lamp can be effected by the use of high quality clear quartz tubing, available and referred to in the industry as VH-quartz, which allows the transmission of UV light at both the 185 and 253.7 nanometer radiation wavelengths. Therefore, by employing a UV lamp having both these types of tubing, in combination with an adjustable sleeve covering a portion of the VH-quartz tubing for blocking or absorbing the transmission of ultraviolet light that will produce ozone, such as that described in U.S. Pat. No. 5,751,007, one can purify and/or treat the air and simultaneously control the production of ozone for eliminating offensive and/or noxious odors.
Unfortunately, the control of the rate of ozone emitted in a HVAC duct by a system that employs the UV lamp apparatus described in U.S. Pat. No. 5,751,007, is hampered by the duct system that conveys the conditioned air, either because of the inaccessibility of the UV lamp itself, or because of the necessity of having to shut down the UV air disinfection system to manually adjust the sleeve which, in this patent, is mounted directly to the lamp's tubing. It is therefore important and desirable to monitor the levels of ozone and provide for the manual and/or automatic adjustment of the sleeve from a location exterior and/or remote from the duct system, without having to shut down the operation of the UV air disinfection system. Discontinuing operation of the system to either change the lamp or to manually adjust the sleeve's position for controlling the UV lamp's ozone output also leads to an inefficient operation. Furthermore, it should be kept in mind that while the formation of ozone within the duct is desirable for reducing and/or eliminating noxious odors, the ozone produced should not reach levels where it becomes toxic to the persons being exposed to it, since prolonged exposure to elevated levels of ozone can be harmful.
BRIEF DISCLOSURE OF THE INVENTION
In order to overcome the foregoing difficulties, the present invention provides an ultraviolet light apparatus, module and system for the treatment of air within a confined structure, such as a HVAC duct, to disinfect the air therein, and for controlling the amount of ozone generated by the ultraviolet light apparatus for substantially reducing and/or eliminating offensive and/or noxious odors carried by the air within the confined structure.
The ultraviolet light apparatus comprises an ultraviolet light-emitting lamp that includes at least one composite tubing which comprises (a) a first section for transmitting ultraviolet light in a wavelength range that includes maximum ozone production and maximum germicidal activity; and (b) a second section for transmitting ultraviolet light in a wavelength range that includes maximum germicidal activity and excludes the production of ozone. The ultraviolet light apparatus also includes (c) a movable annular sleeve whose annulus completely surrounds a portion of the composite tubing of the ultraviolet light-emitting lamp in a frictionless manner. The sleeve is capable of blocking ultraviolet light in a wavelength range that produces ozone while simultaneously allowing the transmission of ultraviolet light at a wavelength range that produces germicidal activity.
The ultraviolet light-emitting lamp may be configured as comprising a straight composite tubing, or it may comprise two, substantially parallel, tubularly connected segments, the first section of the composite tubing forming a portion of at least one of the segments. This includes a UV lamp having a generally C-shaped configuration whose opposite ends terminate in a common lamp base.
The annular sleeve is such that it is capable of blocking ultravio
Disabito James L.
Kurtz Mark E.
Russell Scott P.
Law Offices of Kenneth F. Dusyn
Nguyen Kiet T.
Ultravation, Inc.
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