CAPILLARY SENSOR TUBE FLOW METERS AND CONTROLLERS

摘要

Capillary-type mass flow meters and controllers are described that employ temperature sensor hardware providing boundary conditions as necessary for direct computation of mass flow rate. The approach offers dramatically improved operable range and other potential benefits as compared to known systems.

主权项

1. A thermal mass flow meter or controller apparatus comprising:
a flow body including a laminar flow element; a capillary sensor tube received within a compartment; at least one self-heated temperature sensor coiled around the capillary tube; an additional temperature sensor (T1) positioned on or adjacent to the sensor tube from adjacent to the at least one self-heated temperature sensor to adjacent to an upstream edge of the compartment; and a computer processor configured to determine total mass flow rate (qm, tot) in real time using an output from the T1 sensor as a boundary condition for calculation.