Flow velocity sensor and flow velocity detection method

A flow velocity sensor to detect a flow velocity of a fluid in a pipe, the flow velocity sensor comprising:

• a high sensitivity detector and a low sensitivity detector each including:
• a main body that is deformable by receiving pressure of the fluid;
• and
• a sensor to detect a deformation amount of the main body;
• wherein
• the main body includes:
• a deformation portion provided with the sensor;
• and
• a pressure receiving portion to receive pressure of the fluid and deform the deformation portion;
• the low sensitivity detector is configured to detect the flow velocity of the fluid with lower sensitivity than the high sensitivity detector;
• a ratio of a pressure receiving area of the pressure receiving portion of the high sensitivity detector to a rigidity of the deformation portion of the high sensitivity detector is larger than a ratio of a pressure receiving area of the pressure receiving portion of the low sensitivity detector to a rigidity of the deformation portion of the low sensitivity detector;
• a pair of the high sensitivity detectors is disposed so as to sandwich the low sensitivity detector in a flowing direction of the fluid;
• and
• a predetermined gap is provided between each of the high sensitivity detectors and the low sensitivity detector.