Air conditioning systems sometimes play an unintended role as a source of pathogenic microorganisms. Under certain conditions frequently common in the evaporator section of an air conditioning system, mold can grow on the evaporator coil and drain pan surfaces, thereby affecting overall air quality. As a viable method to control the microbial growth, UltraViolet Germicidal Radiation (UVGR) sterilization has gained public acceptance. More specifically, ultraviolet C-band (UVC) radiation within the evaporator assembly provided by a UVC lamp improves air quality and maintains system efficiency by keeping the evaporator mold-free.
However, UVC can cause eye injury and therefore must be carefully integrated with the evaporator assembly. To prevent such injury, a safety interlock mechanism is often integrated with UVC lamp units preventing illumination of the lamp unless it is completely installed in its intended position. One system relies upon a spring biasing a switch depressing lever away from the switch when the mounting assembly is not installed in a proper aperture of a duct. This can be defeated readily by installing a UV lamp into the mounting assembly, and then depressing an exposed portion of the switch depressing lever. Another approach is similar with a mounting base that must be in contact with the duct to energize the electrical circuit. It appears that this interlock could be defeated in much the same way as the previous art because it only requires contact with a “depressing surface.”
Accordingly, what is needed in the art is a more positive interlock that prevents electrical circuit activation when the lamp holder is not installed in the base.