thermal mass flow controller / for gas
1640A MKS Instruments

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thermal mass flow controller / for gas thermal mass flow controller / for gas - 1640A


  • Technology:

    thermal mass

  • Fluid:

    for gas

  • Flow rate:

    Max.: 1 l/h (0 us gal/h)

    Min.: 0 l/h (0 us gal/h)

  • Pressure:

    5 psi


The MKS Instruments 1640 Pressure-based Mass Flow Controller is a metal-sealed instrument with standard 3-inch footprint, designed to meter and control gas flows in low-line pressure applications where thermal mass flow controllers are limited in their ability to accurately measure flow. The 1640 utilizes the principle of sonic flow through an orifice, a condition met when the upstream control pressure is at least twice the downstream pressure. Under these conditions, mass flow is proportional to the control pressure.

In the 1640A Pressure-Based Mass-Flo Controller, a Baratron® capacitance manometer monitors the pressure upstream of the critical orifice. This pressure is proportional to flow. The measured pressure is compared in the control electronics to the flow set point. A control signal is then generated to drive the proportional control valve to the conductance as required to bring the actual control pressure (flow) into agreement with the flow set point.