Why is a Thermal Mass Flow meter better than a Pressure Based MassFlow Transducer?
Great question! We hear this all the time and it is why the Sierra meter is such a popular a choice by scientists and technicians “in the know”. Sometimes the pressure based flow transducers are called Volumetric or Mass Flow Meters. A pressure based meter is essentially a “Volumetric” device with the addition of the corrections required to compensate for the flowing gas, pressure, temperature and other second and third order effects. Once the temperature, pressure, and other gas properties are known an on-board computer can manipulate the variables to indicate any of the desired parameters. One of the leading problems is these meters are difficult to properly “correlate” because the mechanical construction of the orifice, or pressure creating means, requires VERY CRITICAL dimensions and fabrication techniques in order to properly follow the theory that dictates their operation. As such some companies invoke “K-Factors” that attempt to overcome these difficult and costly manufacturing
