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Thermal Dispersion Flow Switches for Use With Gases


Item# FST-321-SPST

In stock

Lead Time (If not in stock): 8 weeks
Thermal Dispersion Flow Switches for Use With Gases FST-321-SPST FST-321-SPST
  • Measure Mass Flow of Gases
  • High Reliability, No Moving Parts
  • Effectively Monitor Critical Gas Flows
  • May Be Used in Small Piping or Large Ducts

FST-321-SPST Model Options

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Process Connection Size
Wetted Materials
Media Type
Velocity Range
Max Operating Pressure
Max Process Temperature
Process Connection Type
Switch Rating and Type
Supply Power
Wire Length

  • Maximum Pressure 150
  • Switch Operation Selectable NO or NC states

OMEGA’s FST-320 Series thermal dispersion flow switches, especially designed for use with gases, sense changes in the heat transfer characteristics of the gases. Flow velocities from 1 to 90 fps are effectively monitored. The flow switch incorporates a standard SPST Relay switch output for control flexibility. The OMEGA® LVCN-131 and LVCN-141 controllers can easily be interfaced to perform a variety of control functions. The FST-320 family of sensors can be easily installed in line sizes ranging from 3/4 to 12'.

Range: 1 to 90 fps
Accuracy: ±5% of setpoint at constant temperature and flowrate
Response time: 10 seconds after initial 30 sec warm up
Setpoint Drift with Fluid Temperature: 0.5% per °C
Voltage Input: 12-36 Vdc @ 60 mA
Contact Output: 1 A SPST Relay, selectable NO or NC states
Fluid Temperature: 0 to 60°C (32 to 140°F)
Max Fluid Pressure: 150 psi @ 25°C (77°F) derated @ 1.667 psi per °C above 25°C (77°F)
Wetted Materials: PP with PVDF
Cable Length: 3 m (10 ft)
Max Cable Length: 305 m (1000 ft)
Dimensions:76.2 or 114.3 x 26.7 mm dia.(3.0 or 4.5 x 1.05')

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