Compressor Protective Temperature Sensor The compressor protective temperature sensor is a pneumatic bleed off thermostat, which contains a fluid-filled sensing element and a ball metering valve. The unit is in the duct up- stream of the turbine/compressor assembly. The thermostat is connected pneumatically to the flow modulation system pressure regulator valve and responds to air temperature. As the air temper- ature increases, the fluid in the sensing element expands and opens the ball metering valve, which vents control pressure from the flow modulating valve. This causes the regulator to close, de- creasing the bleed-air flow, which slows the rpm of the turbine assembly, thus protecting it from damage because of overtemperature. Turbine Protective Temperature Sensor The turbine protective temperature sensor is identical to the compressor protective temperature sensor except for calibrated temperature and location. The turbine protective temperature sensor is in the turbine inlet duct. Secondary Heat Exchanger The secondary heat exchanger is a cross-flow, air-to-air heat exchanger. Hot, high-pressure air, discharged from the compressor end of the refrigeration turbine/compressor assembly, is transported through the core of the heat exchanger where ram air, augmented by water spray, is forced across the core by aircraft forward motion, absorbing heat from the air and reducing the air temperature. During ground and low-speed operation, cooling air is pulled across the heat exchanger core by ejecting hot air into the heat exchanger exit duct. The ejected air is controlled by the secondary ejector valve in response to signals from the ADC. Secondary Ejector Valve The secondary ejector valve is a normally open in-line poppet, pneumatically actuated, solenoid- controlled shutoff valve. The valve controls the flow of bleed air to the secondary heat exchanger ejector in the secondary heat exchanger exit duct. The valve is controlled by an electrical signal from the ADC. At airspeeds below 165 knots, this valve operates on the same principle as the primary ejector valve. Water Spray Nozzle The water spray nozzle is used to form a mist in the secondary heat exchanger ram air inlet, which aids in cooling the air. Water is extracted from the conditioned air in the water extractor. The water is transported to the water spray nozzle into the secondary heat exchanger ram air inlet. The nozzle directs a jet of water onto a pin, forming a fine sheet of water before breaking up into a mist. The mist is forced across the heat exchanger with the ram airflow. Reheater Heat Exchanger The reheater heat exchanger is a single-pass, cross-flow, air-to-air heat exchanger. The reheater heat exchanger cools air from the secondary heat exchanger before moisture removal in the condenser/vent suit heat exchanger and water extractor and simultaneously reheats the dried air before expansion through the turbine end of the refrigeration turbine/compressor assembly. The function of the reheater is to decrease the amount of cooling provided by the condenser heat exchanger and increase turbine inlet temperature, which results in increased turbine power. Condenser/Vent Suit Heat Exchanger The condenser/vent suit heat exchanger is a cross-flow, air-to-air heat exchanger, which uses cold turbine discharge air from the refrigeration turbine/compressor assembly to cool and condense moisture from the bleed air before circulation through the water extractor. The heat exchanger inlet receives partially cooled air from the hot side of the reheater and directs it across the condenser core where it is cooled until the water vapor is condensed into large size droplets. The air and water droplets are directed to the water extractor. A separate vent suit heat exchanger is in the condenser assembly. The vent suit heat exchanger receives dry air from the water extractor and cools it by heat exchange with turbine exhaust air for use in the vent suit system. Water Extractor The water extractor is an in-line, integral duct device that uses a helix and a water shave-off collector. Moisture-laden air from the condenser enters the water extractor and is given a swirling motion by the helix. The heavy water particles are centrifuged to the duct wall and shaved off into 3-6