Patent ID: 6892591

Claim:
In an accelerated weathering apparatus having a test chamber, a specimen support, a light source powered by a power source controlled by a ballast, a pair of chamber air temperature sensors disposed before and after the test chamber, a black panel temperature sensor, an air heater, and a dual blower system for drawing and circulating fresh and recirculated air, said dual blower system including a fresh air blower and a recirculation air blower, a method for controlling both air and black panel temperatures within the test chamber, said method comprising: (a) selecting a desired irradiance; (b) selecting a desired chamber air temperature and a desired black panel temperature; (c) sensing the chamber air temperature; (d) sensing the black panel temperature within the test chamber; (e) comparing the sensed chamber air temperature the selected chamber air temperature; (f) comparing the sensed black panel temperature to the selected black panel temperature; and (g) in response to comparing steps (e) and (f), adjusting a speed of at least one of the fresh air blower and the recirculation air blower.