US 7,321,833 B2
Fluid flow rate sensor
Michael DuHack, Indianapolis, Ind. (US); Bernd D. Zimmermann, Ashland, Ind. (US); and Tung-Sheng Yang, Mansfield, Ohio (US)
Assigned to Emerson Electric Co., St. Louis, Mo. (US)
Filed on Jul. 11, 2006, as Appl. No. 11/485,562.
Application 11/485562 is a continuation in part of application No. 10/963750, filed on Oct. 13, 2004.
Prior Publication US 2006/0265151 A1, Nov. 23, 2006
Int. Cl. G01F 1/00 (2006.01)
U.S. Cl. 702—47  [702/45; 73/204.13] 16 Claims
OG exemplary drawing
 
1. A fluid valve assembly, comprising:
a valve body defining an inlet, an outlet and a valving cavity disposed between and communicating with the inlet and the outlet, and a valving surface between the inlet and the outlet;
a valve moveable to a position away from the valving surface for permitting flow from the inlet through the valving cavity to the outlet, and moveable to a position contacting the valving surface for preventing flow from the inlet through the valving cavity;
a fluid flow rate sensor disposed between the inlet and the outlet and having a probe including a detection module adapted to change condition in response to the presence of the flow of fluid;
a control module electrically connected to the probe, the control module monitoring the condition of the detection module over time, determining a rate of change of the condition over time, and generating an output that is indicative of the rate of flow of the fluid;
an I/O module connected to the control module and communicating the output of the control module to another device;
a detection circuit comprising a plurality of thermistors and a plurality of resistors, the detection circuit adapted to provide a voltage that varies in response to a change in temperature of the thermistors; and
a heating circuit comprising at least one resistor in thermal communication with at least one thermistor.