US 2002/0170352 A1 · Flow rate detector

Abstract

The invention provides a flow rate detector capable of precisely detecting a flow rate of an object fluid and effectively reducing a leaning error even when the object fluid is pulsating, thereby improving precision in detection of flow rate. The flow rate detector comprises a flow detector 50 for outputting a flow-detecting signal Sf according to a flow rate of the object fluid utilizing heat transfer phenomenon from an exothermic resistor 12 disposed in a fluid passage to the object fluid, and a gain compensator 60 for compensating an error in a flow-detecting signal Sf by amplifying the flow-detecting signal Sf from the flow detector 50, wherein the gain compensator 60 is arranged to amplify the flow-detecting signal Sf by a substantially constant alternating current gain G3 larger than a direct current gain G1 at the time of zero frequency, in a frequency range higher than a frequency f2A corresponding to the minimum pulsating frequency of the object fluid.

Claims10

Dependent claims

A flow rate detector comprising:

flow detecting means for outputting a flow-detecting signal according to a flow rate of an object fluid utilizing heat transfer phenomenon to the object fluid from an exothermic resistor disposed in a fluid passage;
and
gain compensating means for compensating a gain of said flow-detecting signal by amplifying said signal outputted by said flow detecting means;
wherein said gain compensating means amplifies said flow-detecting signal with a substantially constant alternating current gain larger than a direct current gain at the time of zero frequency in a frequency range higher than a minimum pulsating frequency of the object fluid.

1 more element

A flow rate detector comprising:

temperature detecting means for separately detecting temperatures of thermo-sensitive resistors respectively disposed on upstream side and downstream side of an exothermic resistor disposed in a fluid passage;
and
flow rate computing means for computing a flow-detecting signal based on a temperature detecting signal outputted by said temperature detecting means;
wherein said flow rate computing means consists of:
first phase compensating means for amplifying and outputting a phase-advanced temperature detecting signal of an advanced phase corresponding to a temperature of a thermo-sensitive resistor disposed on upstream side of said exothermic resistor;
second phase compensating means for amplifying and outputting a temperature detecting signal of an advanced phase corresponding to a temperature of a thermo-sensitive resistor disposed on downstream side of said exothermic resistor;
and a differential amplifier for outputting as a flow-detecting signal a difference between output signals from said respective phase compensating means.

4 more elements

Dependencies are inferred from the claim text.

Flow rate detector

Life of this patent

Flow rate detector

Life of this patent

Abstract

Claims10