Title:
FLOW RATE TRANSMITTER
Document Type and Number:
Japanese Patent JP3881348
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To normally detect a magnetic field from a transmitting magnet without glitch due to the effect of terrestrial magnetism even if the magnitude of the magnetic field transmitted from the transmitting magnet embedded in a rotor to an amorphous sensor becomes small.
SOLUTION: The invention is for detecting the magnetic field from the transmitting magnetism embedded in the end surface of the rotor rotating in proportion to the flow rate of measuring fluid by using the amorphous sensor, and comprises a coil for an external magnetic field canceling which is put in the vicinity of the amorphous sensor, a magnetic sensor arranged in the vicinity of the amorphous sensor for detecting the external direct current magnetic field in the same direction as the amorphous sensor, and a controller for controlling the current sending to the coil for external magnetic field canceling for canceling the external direct current magnetic field detected with the magnetic sensor. The external direct current magnetic field affecting to the amorphous sensor is canceled by the magnetic field generated by the coil for external magnetic field canceling.
Inventors:
Yoshio Asanuma
Application Number:
JP2004140567A
Publication Date:
February 14, 2007
Filing Date:
May 11, 2004
Export Citation:
Assignee:
Oval Co., Ltd.
International Classes:
G01F3/10; G01R33/09; (IPC1-7): G01F3/10; G01R33/09
Domestic Patent References:
| JP2115124U | ||||
| JP8179020A | ||||
| JP2003149311A |
Attorney, Agent or Firm:
Yuzuru Okawa
Yutaka Morita
Yutaka Morita
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