Air-flow activated germicidal UV-C lights in HVAC system

It is well known that sunlight purifies air. More specifically, it is the light in the UV-C wavelength range (around 260 nm) that purifies air. UV-C light is germicidal by deactivating the DNA of viruses, bacteria, and dust mites. However, this natural germicidal process doesn't occur indoors. Many UV-C germicidal systems have been invented for indoor uses such as UV-C sanitizing wands, UV-C housing used inside HVAC systems, and etc.

This invention designed an UV-C light assembly for air purification inside HVAC systems.

We use light-emitting diodes (LEDs) or fluorescent light tubes in the wavelength range of UV-C centered at about 260 nm. The UV-C wavelength is peaked at 260 nm with 10 nm of FWHM. The light assembly is placed inside air duct of a HVAC system. When the HVAC system starts to work, the fan drives the air in the duct to flow. The airstream pushes the air cup to press on the switch, and thus causing the switch to close to power up the LEDs or the fluorescent tubes. The UV-C light purifies the air that flow through the light. When the fan stops, the air cup stops pressing the switch and the UV-C light assembly shuts off.

The UV-C light assembly is designed in such a way that it can be fitted through the openings of air filters.

This UV-C light assembly is suitable for any central HVAC systems.

FIG. 1 is a structure of air-flow activated UV-C light assembly.

FIG. 2 is an assembled unit of air-flow activated UV-C light assembly.

FIG. 3 is an illustration of a typical LED circuit.

1. The Physical Structure

The invented UV-C light assembly consists of units as follows:

(a) Assembly Frame ( FIG. 1 )

A frame that can be made of metal or plastics holds all other parts together to form the assembly.

(b) Circuit Board ( FIG. 1 )

The circuit is etched on the board with necessary electronic components and LEDs welded (or fluorescent tubes are installed).

(c) Wind Cup ( FIG. 1 )

The wind cup is designed to catch the air that flows in the duct. A spring system is used to hold the wind cup.

(d) Switch ( FIG. 1 )

The switch is a push-to-make momentary switch, meaning the switch closes when the button is pressed down.

(e) Assembly Cover ( FIG. 1 )

The cover protects its components from any possible harm in the air duct environments.

2. Operation of Air-Flow Activated Germicidal UV-C Light Assembly

Air-flow activated germicidal UV-C light assembly (light assembly) is designed to be used with central HVAC systems. The UV-C light assembly is installed inside air ducts. When air flows, the light assembly turns on. When air flow stops, the light assembly turns off. When the light assembly turns on, it emits UV-C light and illuminates a section of the duct. Air flowing through this light illuminated section is purified by UV-C light. Here is how this light assembly works:

(a) LEDs (or fluorescent UV-C tubes) are installed on the circuit board according to FIG. 3 . When the switch turns on, the LEDs emit UV-C light. (b) If the air in the duct doesn't flow, meaning the HVAC system is off, the wind cup stands up and not in touch with the switch. (c) If the air in the duct flows, meaning the HVAC system is on, the wind cup is being pushed toward the switch. The push from the wind cup turns the switch on. When the switch is on, the LEDs (or the fluorescent tubes) emit UV-C light. (d) While the light assembly is on, the air flows through the illuminated section. The UV-C light purifies the airstream.

U.S. Pat. No. 7,976,195 Engel, et al

An UVC lamp and reflector/shield assembly is designed to be used in a commercial HVAC unit. The reflector in the assembly creates an illuminating pattern. The outer surface of the assembly provides shielding for the UVC lamp from the air flow.

U.S. Pat. No. 8,004,166 Boehme

The author designed a mercury based UVC lamp that prevents the formation of a cold spot in the lamp.

U.S. Pat. No. 8,252,099 and U.S. Pat. No. 8,252,100 Worrilow

An air purifier is designed that includes a housing with an inlet for receiving air and an outlet for exhausting air. The housing has a particle pre-filtration, UV filtration, and volatile organic compound post filtration. This purifier is intended to use in research laboratories.

U.S. Pat. No. 7,837,933 Sevack, et al

This patent is similar to U.S. Pat. No. 7,976,195

U.S. Pat. No. 7,740,686 Metteer

A modular ductwork assembly decontaminates an air stream circulating with a HVAC system. The assembly includes an ionizing module, sterilization module, ozone treatment module. The sterilization module uses UVC light.

U.S. Pat. No. 7,278,272 Huston, et al

A germicidal UVC lamp is mounted near evaporator coil in a HVAC system to sterilize the air and surfaces of the coil.

U.S. Pat. No. 7,175,814 Dionisio

A cartridge device containing UVC for air disinfection comprises individual UV bulb, filter, ballast and electrical components.