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FCD’s • Control Dampers – Opposed blade dampers
FCD’s
• Control Dampers
– Opposed blade dampers
– Parallel blade dampers
– Butterfly dampers
FCD’S
– Globe valves
– Ball valves
– Butterfly valves
Flow characterisitics
• Linear valve – 40%
open 40% flow
• Equal % - best at 50 –
100%, HW and CW
• Quick opening – two
position
Sensors
• Temperature
• Humidity
• CO
• Pressure
• Flow
• ……………
Temperature
• Thermistor
– Non linear
– NTC
– Ceramic semiconductor
Temperature
• RTD’s
– Resistance temperature dectors
– Thin film of pure metal
– Relatively linear
– About .18 degree drift per year
– High cost
