Thermal Mass Flow Meter

TA2_1The Thermatel Enhanced Model TA2 Thermal Mass Flow Meter provides reliable mass measurement for air and gas flow applications. The powerful, yet easy to use, electronics are contained in a  compact explosion proof enclosure. The TA2 is available with both insertion probes as well as flow body design for smaller pipe sizes. The TA2 offers excellent performance at an exceptional value.

Thermal flow meters are primarily used in air and gas flow measurement applications.  The meters consist of a transmitter and probe with temperature sensors (RTD’s) located in the pins at the bottom of the probe.  One sensor measures the process temperature and the other sensor is heated to a specific temperature above this.  As the flow rate increases heat gets taken away from the heated sensor.  Some manufacturers use a variable power operation to keep the temperature difference constant, while others keep the power constant and measure the temperature difference.  The Magnetrol Model TA2 measures the power it takes to maintain a constant temperature difference between the sensors.  This relationship between power and mass flow rate is established during calibration.

Similar to thermal flow meters the switches are based on heat transfer.  One sensor is at the process temperature and the other is being heated by a constant power.  As the flow rate increases, the temperature difference between the sensors decreases.  A set point is established so when that specific temperature difference is reached the relay changes state.  This can be on either increasing or decreasing flow or flow/no flow.  When used in a level or interface application it is primarily the thermal conductivity of the fluid that will provide the difference in heat transfer.


Technology Features

  • Direct mass flow measurement of air and gases
  • High turndown ratios
  • Excellent low flow sensitivity
  • Low pressure drop
  • NIST traceable calibrations

Probe Features

  • All 316 welded stainless steel and Hastelloy® C-276 construction
  • Selection of process connections, including threads, welded flange construction, and use with a compression fitting
  • Process temperatures up to +400° F (+200° C)
  • Pressure rating to 1500 psig (103 bar) dependent upon process connections
  • Probe can be field-replaced
  • Unique sensor design permits higher mass flow rates yet maintains equivalent thermal mass for varying temperature operation
  • Optional hot tap retractable probe assembly

Electronics Features

  • Compact explosion proof/NEMA 4X enclosure, mounted either integrally on the probe or at a remote location
  • Accepts all input power—11.6 to 30 VDC and 100 to 264 VAC
  • 4-20 mA flow signal can be set for either active or passive operation
  • Optional pulse output plus second mA output which can be sued for temperature or different flow range (mA output passive connection only)
  • HART communications with ASM and DTMs available.
  • 2-line x 16 character backlit display with four push-buttons for ease of configuration