Dynamic temperature controlled accelerated weathering test apparatus

An accelerated weathering test apparatus of the type used to concentrate solar radiation upon test specimens, the apparatus being adapted to dynamically control a test specimen temperature to simulate complex temperature cycles of a material end-use application, the apparatus comprising:

• a target board for supporting at least one test specimen to be exposed to concentrated solar radiation;
• a reflector device for reflecting solar radiation and concentrating the reflected solar radiation on to the target board for illuminating the at least one test specimen;
• an air circulation device for circulating ambient air over the target board for cooling the at least one test specimen, the air circulation device including an electric motor and a fan powered by the electric motor for creating a flow of ambient air;
• at least one feedback device mounted to the target board for exposure to the concentrated solar radiation and generating a test signal responsive to the temperature thereof and representative of the test specimen temperature;
• at least two input devices, each for generating a respective dynamic reference signal representative of a different complex temperature cycle of a material end-use application;
• and
• a controller connected to a first switch for alternatively selecting one of the at least two input devices and responsive to the selected dynamic reference signal for generating a temperature set point, and the controller further connected to a second switch for alternatively selecting one of the at least one feedback device and responsive to the selected test signal for selectively controlling the application of electrical power to the electric motor in order to control a rate at which ambient air is circulated over the target board, the rate being generally increased when the temperature of the selected one of the at least one feedback device is greater than the temperature set point, and the rate being generally decreased when the temperature of the one of the at least one feedback device is less than the temperature set point, and the rate being generally maintained constant when the temperature of the one of the at least one feedback device is substantially equal to the temperature set point.

A system for tightly regulating temperature variability amongst a plurality of accelerated weathering test apparatus, of the type used to concentrate solar radiation upon at least one test specimen, during an exposure test where each apparatus is adapted to dynamically control a test specimen temperature to simulate complex temperature cycles of a material end-use application, the system comprising:

• each of the plurality of accelerated weathering test apparatus including:
• a target board for supporting the at least one test specimen to be exposed to concentrated solar radiation;
• a reflector for reflecting solar radiation and concentrating the reflected solar radiation onto the target board for illuminating the at least one test specimen;
• an air circulation device for circulating ambient air over the target board for cooling the at least one test specimen, the air circulation device including an electric motor and a fan powered by the electrical motor for creating a flow of ambient air;
• a feedback device mounted to the target board for exposure to the concentrated solar radiation and generating a test signal responsive to the temperature thereof and representative of the test specimen temperature;
• an input device for continuously generating a dynamic reference signal representative of a complex temperature cycle of a material end-use application;
• and
• a controller connected to the input device and responsive to the reference signal for generating a temperature set point, and the controller further connected to the feedback device and responsive to the test signal for selectively controlling application of electrical power to the electric motor, in order to control a rate at which ambient air is circulated over the target board, the rate being generally increased when the temperature of the feedback device is greater than the dynamic temperature set point, and the rate being generally decreased when the temperature of the feedback device is less than the dynamic temperature set point, and the rate being generally maintained constant when the temperature of the feedback device is substantially equal to the dynamic temperature set point;
• the input device of a first one apparatus disposed remote from the plurality of accelerated weathering test apparatus;
• and
• the input device of each other apparatus consecutively linking in series the first one apparatus and the other apparatus, such that the other apparatus are dependently controlled from the first one apparatus to reduce temperature variability across the system.