Starting at $619.00
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  • For use with clean air and compatible, non-combustible gases
  • Accurate up to ±3%
  • 1.5 second response time
  • Process temperature limit: -40 to 212°F
  • Pressure limit: 100 psi (6.89 bar) maximum
  • Ranges to 15,000 FPM or 75 MPS
  • Optional bright LED display
  • Easy push button set-up
  • Compact housing
  • 4-20 mA output, isolated 24V source, 3 or 4-wire connection
  • Digital filter for signal damping
  • Screw terminal electrical connection
  • 1/2" male NPT process connection


The Dwyer 641 Air Velocity Transmitter is the ideal instrument for monitoring air flow. This transmitter uses a heated mass flow sensor which allows for precise velocity measurements at various flow rates and temperatures. The 641's 16 field selectable ranges provides it the versatility to be selected for several air flow applications. The optional LED produces a complete, low-cost solution for local indication of air flow.

The Dwyer 641 air velocity transmitter is ideal for application such as: exhaust stack flow monitoring, air control in drying processes, HVAC air velocity measurements, fan supply and exhaust tracking, clean room fresh air supply, ensuring proper lab hood exhaust flow rates, and others.


This product can be used in the following applications: