Skip links

HOLIDAY HOURS: All Brooks Instrument facilities in the USA will be closed December 23, 26, 30 and January 2. For holiday hours of our facilities across the globe, please contact the specific location directly.

Variable Area Flow Meters (Rotameters)

Process-proven flow meters. For maximum repeatability and reliability.

As one of the pioneers in variable area (VA) flow meter (rotameter) technology, Brooks Instrument has created a diverse and proven portfolio of flow meters, installed and in use across virtually every industry and application.

This broad portfolio includes armored metal, glass tube and plastic VA flow meters, each engineered to provide years of repeatable, reliable measurement of gas and liquid flow rates. They feature:

  • Reliable, easy-to-read displays
  • Fail-safe flow indication under any circumstance
  • Integral flow controller to compensate for varying pressures
  • Materials and designs to suit multiple pressure ranges
  • Field-replaceable components and custom scales
  • Integration of optional flow switches, automated valves or alarms

Key Applications

  • Basic liquid or gas flow measurement
  • Rotating equipment flow measurement
  • Process analyzers
  • High-pressure flow on offshore oil platforms
  • Chemical injection
  • Purge liquid or gas metering
Brooks MT3809G variable area flow meter cutaway

MT3809 with Explosion Proof Housing, Variable Area Flow Meter
  • Most cost-effective solution for non-corrosive and low pressure applications
  • Excellent measurement repeatability which provides process stability and consistency.
Fluid Type
Gas, Liquids
Flow Range (Full Scale Capacity)
Gas: 40 sccm - 1000 slpm
Liquid: 100 gr/m - 375 kg/m
2-10% FS
Max Pressure
100 psig
72oC (160oF)
Output Type
Visual Indication
  • Improved accuracy over plastic flow meters
  • Suitable for wider flow ranges and and more gas types
Fluid Type

Clean Gases & Liquids

Flow Range (Full Scale Capacity)
Air: 170 scfm - 280 m3n/hr
Water: 98 gpm - 22,000 l/h

1-2% FS

Max Pressure
Refer to Maximum Pressure Ratings Table in Data Sheet
121oC (250oF)
Output Type
Visual Indication
  • For use in high/low pressure and temperature applications
  • Ideal for measuring fluids in hazardous, remote areas
  • Simple design is easy to install and maintain
Fluid Type
Clean Gases, Liquids & Steam
Flow Range (Full Scale Capacity)
Air: 750 scfm - 1200 m3n/hr
Water: 440 gpm - 100,000 l/h
1-10% FS
Class 1.6 - 4 VDI/VDE
Max Pressure
1379 bar / 20,000 psig
420oC (788oF)
Output Type
Visual Indication
4 - 20mA Analog w/HART
Flow Switches