Method and sensor for mass flow measurement using probe heat conduction
First Claim
1. A mass flow sensor comprising:
- a probe having a predetermined length for disposition in the path of mass flow;
means for heating said probe;
at least two first temperature measuring devices disposed at different points along said length for measuring temperatures Tt and Th of said heated probe at said points in the presence of the mass flow;
a second temperature measuring device for disposition in the path of mass flow for measuring the temperature Ta of the mass flow; and
means coupled to said first and second temperature measuring devices for determining differential temperature measurements Th−
Ta and Tt−
Ta and for generating a mass flow signal based on a ratio of said differential temperature measurements (Th−
Ta)/(Tt−
Ta).
1 Assignment
0 Petitions
Accused Products
Abstract
A mass flow sensor is disclosed comprising: a heated probe having a predetermined length for disposition in the path of mass flow; at least two first temperature measuring devices disposed at different points along the probe length for measuring temperatures of the heated probe at such points in the presence of the mass flow; a second temperature measuring device for disposition in the path of mass flow for measuring the temperature of the mass flow; and a processing unit for determining mass flow as a function of the temperature measurements of the first and second temperature measuring devices. A method of measuring mass flow is also disclosed comprising the steps of: disposing a probe of a predetermined length in the path of mass flow; heating the probe; measuring the heated probe temperature at at least two different points along its length in the presence of the mass flow; measuring the temperature of the mass flow; and determining mass flow as a function of the temperature measurements of the heated probe and mass flow. In one embodiment, the mass flow sensor includes at least three temperature measuring devices disposed in proximity to at least one probe for generating signals representative of the temperature of the heated probe along its length and the temperature of the mass flow. The at three temperature measuring devices are coupled together to generate at least two signals representative of temperature differentials in the vicinity of the at least one probe, and the processing unit processes at least one of the temperature differential signals to generate a signal representative of mass flow.
91 Citations
28 Claims
-
1. A mass flow sensor comprising:
-
a probe having a predetermined length for disposition in the path of mass flow;
means for heating said probe;
at least two first temperature measuring devices disposed at different points along said length for measuring temperatures Tt and Th of said heated probe at said points in the presence of the mass flow;
a second temperature measuring device for disposition in the path of mass flow for measuring the temperature Ta of the mass flow; and
means coupled to said first and second temperature measuring devices for determining differential temperature measurements Th−
Ta and Tt−
Ta and for generating a mass flow signal based on a ratio of said differential temperature measurements (Th−
Ta)/(Tt−
Ta).- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method of measuring mass flow comprising the steps of:
-
disposing a probe of a predetermined length in the path of mass flow;
heating said probe;
measuring the heated probe temperature at at least two different points along its length in the presence of the mass flow to provide at least temperature measurements of Th and Tt at said points;
measuring the temperature Ta of the mass flow;
determining differential temperature measurements Th−
Ta and Tt−
Ta; and
determining mass flow as a ratio of said differential temperature measurements (Th−
Ta)/(Tt−
Ta).- View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
-
-
23. A mass flow sensor comprising:
-
a probe having a predetermined length for disposition in the path of mass flow;
a heating element integral to said probe for heating said probe;
a first thermocouple integral to said probe and extending substantially beyond the length of said probe for measuring a temperature Ta of the mass flow outside of said probe;
a second thermocouple integral to said probe and disposed along the length of said probe in close proximity to the heating element for measuring a temperature Th of said probe at said heating element;
at least one third thermocouple integral to said probe and disposed along the length of said probe away from said heating element for measuring a temperature Tt of said heated probe in the path of mass flow;
wherein said first and second thermocouples being coupled together to generate a first signal representative of the temperature differential (Th−
Ta);
wherein said first and at least one third thermocouples being coupled together to generate a second signal representative of the temperature differential (Tt−
Ta); and
means coupled to said first and second signals for processing said temperature differential signals to generate a signal representative of mass flow. - View Dependent Claims (24, 25, 26, 27, 28)
-
Specification