Model 840 Side-Trak® Premium Mass Flow Controllers


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For precise mass flow control of any clean dry gas including mixtures, toxics, corrosives, and combustibles, consider the Model 840 Side-Trak® MFC. Our Model 840 has proven to be one of the most dependable flow controllers in the world over the last 20 years.

Our Model 840 is widely used in process control, leak detection, gas distribution and scientific research applications among many others. The integrated electro magnetic control valve provides precise, instantaneous control of gas delivery over the full range of the product.

Our Model 840 uses Sierra’s patented sensor design with access ports to facilitate easy sensor cleaning.  In addition, Sierra’s Platinum Sensor Technology eliminates zero-drift and creates excellent long-term reliability.

Unique Product Features

  • Accuracy of +/- 1% of full scale
  • 316 stainless steel construction
  • Flow ranges from 0-10 sccm to 0-5600 slpm
  • Direct monitoring of mass flow rate
  • Fast-response (1 second) control valve
  • “Primary Standard” calibration for best accuracy & NIST traceability
  • CE approved