Stafford, Texas

LIQUI-FLOW Series, Digital Thermal Mass Flow Meters and Controllers

LIQUI-FLOW Series, Digital Thermal Mass Flow Meters and Controllers

LIQUI-FLOW digital liquid flow meters and controllers for low flow ranges operate on a thermal, through-flow measuring principle. The instruments are equipped with a digital pc-board, featuring self-diagnostics, alarm and counter functions, digital communication (RS232), and a variety of Fieldbus options.

Through-Flow Measurement of Low Liquid Flow Rates

  • Lowest range 0.25 … 5 g/h
  • Highest range 20 … 1000 g/h for fluids with thermal properties similar to H2O


  • Fast and accurate measurement
  • No moving parts
  • Thru-Flow measurement
  • Suitable for liquids with low boiling point
  • Attitude insensitive
  • Very small internal volume
  • In combination with a control valve: continuous and stable control
  • Analog or digital: RS232, PROFIBUS DP, DeviceNet, Modbus, EtherCAT or FLOW-BUS


LIQUI-FLOW Digital Thermal Mass Flow Meters and Controllers Model Line-Up

Liquid Flow Meters

Liquid mass flow meters of the LIQUI-FLOW Series are built around a stainless steel tube without any moving parts or obstructions. The heater/sensor assembly is arranged around the tube and, by following the anemometric principle, a constant difference in temperature (ΔT) is created and the energy required to maintain the ΔT is dependent on the mass flow rate. Due to the benefits of the unique patented sensor, the fluid will be warmed to a maximum of 5°C, thereby making the LIQUI-FLOW Series suitable for fluids with low boiling points.

Liquid Flow Controllers

Flow control is achieved by integrating a control valve onto the body of the liquid flow meter. This control valve has a purge connection to eliminate air or gas during start-up. The electronic control function forms part of the normal circuitry in the meter.

For ultra low flow ranges, see the µ-FLOW series. Ranges: 1.5 … 30 mg/h up to 0.1 … 2 g/h IPA- or H2O-equivalent.

Full Scale capacities (based on H2O) versus Pressure Rating

PN 100 bar (Mass Flow Meter) PN 100 bar (Mass Flow Controller)
L13  |  5 … 100 g/h L13V12  |  5 … 100 g/h
L23  |  100 … 1000 g/h L23V12  |  100 … 1000 g/h