초록 ▼

A flow sensor including a symmetrical sensor tube for carrying the fluid, first and second heaters symmetrically disposed at the sensor tube, and a first temperature sensor in thermal communication with the fluid. A flow meter including a flow sensor having a sensor tube, a first heater disposed at

A flow sensor including a symmetrical sensor tube for carrying the fluid, first and second heaters symmetrically disposed at the sensor tube, and a first temperature sensor in thermal communication with the fluid. A flow meter including a flow sensor having a sensor tube, a first heater disposed at the sensor tube, a second heater disposed at the sensor tube, and a first temperature sensor in thermal communication with the fluid. The meter also includes a circuit for selectively applying power to the first and second heaters to maintain a temperature difference between a temperature of the first and second heaters and the temperature of the fluid, and for determining a difference in power supplied to the first and second heaters. A method including providing first and second heaters at a temperature a fixed amount above a temperature of the fluid; determining a difference in power supplied to the first and second heaters; and determining a measurement of the fluid from the difference in power supplied to the first and second heaters.

대표청구항 ▼

[ We claim:] [1.] A flow meter for measuring a fluid having a temperature, comprising:a flow sensor including a sensor tube, a first heater disposed at said sensor tube, a second heater disposed at said sensor tube, and a first temperature sensor in thermal communication with the fluid; anda circuit

[ We claim:] [1.] A flow meter for measuring a fluid having a temperature, comprising:a flow sensor including a sensor tube, a first heater disposed at said sensor tube, a second heater disposed at said sensor tube, and a first temperature sensor in thermal communication with the fluid; anda circuit for selectively applying power to said first and second heaters to provide said first and second heaters at a temperature a fixed amount above the temperature of the fluid, and for determining a difference in power supplied to said first and second heaters, wherein the power supplied to said first and second heaters is determined from a product of a voltage and a current supplied to each of said first and second heaters.