Mass Flow Controllers & Meters


MW–Low Pressure Drop Gas Mass Flow Meters

High-accuracy, multivariate flow measurement with minimal system impact


Order Directly from Alicat

“Whisper” series mass flow meters with low pressure drop are the perfect instruments for measuring mass and volumetric flow rates. Low pressure drop minimizes system impact, enabling flow measurement at near-atmospheric pressures or when there is little available system pressure. A very wide usable flow range and on-board calibrations for multiple gases will keep this flow meter in operation for a long time.

  • Accurate. Measure flows with NIST-traceable accuracy for a variety of gases down to 0.01% of full scale, or define your own gas composition with COMPOSER™.
  • Easy to Use. As soon as you turn on the flow meter, it’s ready to display live flow, pressure and temperature readings in your choice of engineering units.
  • Connected. Alicat flow meters feature dual digital and analog communications by default and can be ordered with EtherNet/IP, EtherCAT, DeviceNet, Profibus or Modbus (RTU and TCP/IP) communications for easy integration into your digital industrial or laboratory network.
  • Portable. MWB series portable flow meters are designed to be carried and can withstand drops if they should occur.


  • Available ranges: max 0-1000 slpm, min 0-0.5 sccm/0-500 sμlm
  • Flow measurement range: 0.01% – 100% of full scale.
  • Standard accuracy calibration, NIST-traceable: +/- (0.8% of the reading + 0.2% of the full-scale range)
  • Optional high-accuracy calibration, NIST-traceable: +/- (0.4% of the reading + 0.2% of the full-scale range)
  • Repeatability: 0.2% of the full-scale range
  • Typical measurement response time constant: 5-10 ms
  • No warm-up time required

Operating Conditions

  • Compatible gases: 98 pre-loaded selectable gas calibrations; additional mixtures definable with COMPOSER
  • Operating temperature: -10°C to +60°C
  • Max internal pressure (static): 45 psig (60 psia)
  • Max differential pressure (inlet to outlet): 15 psid
  • Proof pressure: 175 psig (190 psia)
  • STP/NTP: user-selectable (defaults to 25°C & 1 atm STP/0°C & 1 atm NTP)

In the box

Model Variations 

Build Options

  • Communications protocols (analog, RS-232, RS-485, DeviceNet, EtherCAT, EtherNet/IP, Modbus RTU or TCP/IP, PROFIBUS)
  • Displays (monochrome or color, integrated or panel-mount)
  • Process connections (NPT, SAE, AN, BSPP/G, welded compression or VCR/VCO fittings)
  • Elastomers (Viton, FFKM, EPDM, Silicone)

Performance Options

Alicat’s MW series is suitable for use with non-corrosive gases.


Monitoring and Recording Bioreactor Output

Applications like methane production or hydrogenation benefit from comparing the mass of gas added to the bioreactor with the mass that has been outgassed. When outgassing occurs at atmospheric pressures, the very low pressure drop of Alicat’s Whisper series will not induce backpressure while quantifying outgassed mass.

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