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