Title:
HEAT-TYPE FLOW-RATE DETECTING APPARATUS
Document Type and Number:
Japanese Patent JPH03134518
Kind Code:
A
Abstract:
PURPOSE:To make it possible to measure a flow rate accurately by depositing and forming two offset electrodes on a substrate in the vicinities of heater electrodes, and applying a voltage across the offset electrodes through an offset power source whose voltage can be adjusted. CONSTITUTION:Heater electrodes 12 and 14 are deposited and formed at the center of an element 10 comprising a ceramic semiconductor. A DC voltage V1 from a heater power source 16' is supplied to the electrodes 12 and 14. Two detecting electrodes 16 and 18 are deposited and formed on both sides of the electrode 12. Furthermore, offset electrodes 20 and 22 are deposited and formed in the vicinities of the electrodes 16 and 18 on the element 10. An offset power source 24 which outputs an adjustable voltage V2 is connected to the electrodes 20 and 22. The distribution of the temperature generated at the surface of the element by the heat supplied from the electrodes 12 and 14 forms symmetrical curves with the electrodes 12 and 14 as the centers. At this time, the potentials at the electrodes 16 and 18 become equal. When a flow is generated in fluid in this state, the accurate flow speed can be measured between the electrodes 16 and 18 without application of any voltage across the electrodes 20 and 22.
Inventors:
KUMANDA AKIRA
Application Number:
JP27326889A
Publication Date:
June 07, 1991
Filing Date:
October 19, 1989
Export Citation:
Assignee:
MURATA MANUFACTURING CO
International Classes:
G01F1/68; G01F1/692; G01F1/696; (IPC1-7): G01F1/68
Attorney, Agent or Firm:
Kenji Yoshida (2 outside)