US 7,007,549 B2 · AC type flowmeter and method of mapping flow rate data for the same

Abstract

The present invention relates to a flowmeter suitable for a micro flow sensor. The flowmeter of the present invention comprises a resistive heater to be inserted into a fluid, AC power with a first frequency supplied to the resistive heater to periodically heat the resistive heater, a signal processing unit for detecting a first signal from the resistive heater in relation to a temperature variation of the resistive heater by the AC power, and obtaining a phase lag of the first signal relative to the heat generation in the resistive heater, and an operation unit for calculating a flow rate based on the obtained phage lag. According to the present invention, the flowmeter of the present invention has a wide measurement range and high measurement accuracy with a simple structure.

Claims9

Dependent claims

A flowmeter, comprising:

a resistive heater to be inserted into a fluid;
Alternating Current (AC) power with a frequency ω to periodically heat the resistive heater;
a signal processing unit having electrical contact at both ends of the resistive heater for receiving signals generated in the resistive heater and for detecting a 3ω voltage signal generated in relation to a temperature variation of the resistive heater by the AC power among the received signals, and obtaining a phase lag of the 3ω voltage signal relative to the heat generation in the resistive heater;
and
an operation unit for calculating a flow rate of the fluid based on the obtained phase lag.

2 more elements

Dependencies are inferred from the claim text.

AC type flowmeter and method of mapping flow rate data for the same

Life of this patent

AC type flowmeter and method of mapping flow rate data for the same

Life of this patent

Abstract

Claims9