Patent ID: 8037774

Claim:
A state detection device that detects a parameter such as a property or state of a fluid, a state of a magnetic field, or a state in a measuring pipe, comprising: a measuring pipe through which a fluid flows; at least one electrode in the measuring pipe that detects an electromotive force generated by a magnetic field applied to the fluid and flow of the fluid; an exciting unit including the electrode that applies a time-changing magnetic field symmetrical to an axial plane of the electrode that is perpendicular to an axis of the measuring pipe; at least one signal line that is connected to the electrode at one end thereof at an angle to the magnetic field that is parallel to the axial plane of the electrode, such that an electromotive force is generated by a change with passage of time in the magnetic field; and a state quantifying unit that is connected to the other end of the signal line to extract a ∂A/∂t component from resultant electromotive forces that are detected at the electrode and the signal line and are composed of an electromotive force of the ∂A/∂t component irrelevant to a flow velocity of the fluid and resulting from a change with passage of time in the magnetic field and an electromotive force of a v×B component relevant to the flow velocity of the fluid, and extracts a variation factor relevant to the parameter from the ∂A/∂t component to quantify the parameter based on the variation factor.