SINGLE-PROBE MASS FLOW METERS

摘要

Microprocessor-based thermal dispersion mass flow meters (i.e., thermal anemometers) are described that use temperature sensing elements in its flow sensor probe(s) in addition to the two elements commonly used. Such systems allow for automatically managing changes in gas selection, gas temperature, gas pressure, and outside temperature. One mass flow meter described has a flow sensor with four temperature sensing elements, wherein one pair is provided in a temperature sensor probe and another pair in a velocity sensor probe. Another variation operates without a separate temperature sensor probe and integrates all function into a single three-sensor probe. Such a device may also be used in conjunction with a one- or two-sensor temperature probe.

主权项

1. A mass flow meter apparatus for immersion in fluid flow comprising:
a probe including a Resistance Temperature Detector (RTD) having a heated length and electrically coupled to a proximal end of the probe; a second temperature sensor adjacent to a proximal end of the heated length, an active region of the second temperature sensor located a distance from the heated length equal to or less than about three times a diameter of the velocity sensor probe, and a third temperature sensor to determine fluid flow temperature, wherein the apparatus includes no separate temperature sensor probe.