| 摘要 |
<p>An environmental chamber for providing thermal stress screening is comprised of a plurality of modular components which may be quickly assembled and disassembled for ease of maintenance and repair. In particular, a heater/cooling unit is coupled by means of a plurality of quick release lockable fasteners to a plenum module. The plenum module in turn is coupled by means of additional quick release lockable fasteners to a blower module. The plenum module in turn is comprised of a heater plenum which communicates with a blower plenum. Gas is drawn into the heater plenum and passed over heating coils which are disposed into the heating plenum from the heating/cooling module. The gas is then communicated to a blower plenum. Cryogenic nitrogen gas is constantly bled through a small (.015'') hole of the liquid nitrogen valve body and is selectively provided to the blower plenum from the heating/cooling module. The selectively heated or cooled gas is then expelled from the blower plenum by means of a blower which extends into the blower plenum from the blower module. Selective heated and cooled gas is directed to a part under test as selectively activated through proportional, integral and derivative control in response to the temperature requirements of the part under test and not in response to the gas delivered to the part or from the blower plenum.</p> |
