Abstract: A method is provided for preventing microbial growth on the collector plates (42) of an electronic air cleaner (10) by directing germicidal light, advantageously ultraviolet light, upon the surface of the collector plates (42) and the particulate material deposited thereon. At least one germicidal lamp (50) is disposed to irradiate ultraviolet light upon the collector plates (42) to destroy microbes that might be growing on the particulate material collected on the plates (42).

Abstract: An electronic air cleaner (10) includes a housing (20), a mechanical prefilter (30), an electrostatic precipitator cell (40) and at least one germicidal lamp (50). The electrostatic precipitator cell (40) includes a plurality of collector plates (42) for collecting thereon particulate material from the air stream. The germicidal lamp or lamps (50) are disposed to irradiating the collector plates (42) and any particulate material collected thereon with germicidal light to destroy microbial growth that might occur on the particulate material deposited on the collector plates. Reflectors (60) may be provided in operative association with the germicidal lamp or lamps (50) to concentrate the germicidal light unto the collecting surface of the collector plates (42).

Abstract: A method for testing a non-hydrocarbon refrigerant, such as CFC-12 or HFC-134a, in a closed system for hydrocarbons, HCFC-22 refrigerant and ammonia is provided wherein a sample of the non-hydrocarbon refrigerant is withdrawn from the closed system, the pressure of the sample is measured and a metered portion of the sample is passed through a test apparatus (20) including a testing tube (30), a testing tube holder (40) for supporting the testing tube (30) and outfitted with a vent (48) to the atmosphere, and a pressure gauge (70) for indicating the pressure of the sample withdrawn. A medium (38) for indicating the presence of hydrocarbons in the sample flow passing through the testing tube is deposited on a surface disposed in the testing tube. The presence of undesired HCFC-22 refrigerant in the CFC-12 or HFC-134a is indicated by a higher pressure reading on the pressure gauge (70).