Title:
COMPOSITE TYPE FLOW METER
Document Type and Number:
Japanese Patent JPH04113228
Kind Code:
A
Abstract:
PURPOSE:To properly judge a failure mode which is peculiar to a flow sensor by diagnosing failure and state of the flow sensor in a composite-type flow meter. CONSTITUTION:When an output P1 changes from a preset initial value to a specified value according to secular change of upstream and downstream temperature-sensitive resistors 21 and 22 and fixed resistors 23 and 24 of a flow sensor 1 and an offset drift of a differential amplifier 25, a microcomputer 3 outputs an alarm A of failure. Also, when the microcomputer 3 receives a flow signal from a Karman flow meter 2 and when outputs P1 and P2 of the flow sensor 1 are equal to 0, the microcomputer 3 gives a warning for open- circuit failure of the upstream temperature-sensitive resistor 21. Also, when there is no flow signal from the Karman flow meter 2 and the output P1 of the flow sensor 1 exceeds and allowable value, for example 640 pulses, and the output P2 exceeds 1390 pulses, the microcomputer 3 issues a warning of open-circuited downstream temperature-sensitive resistor 22.
Inventors:
OISHI YASUHARU
Application Number:
JP23061490A
Publication Date:
April 14, 1992
Filing Date:
September 03, 1990
Export Citation:
Assignee:
YAMATAKE HONEYWELL CO LTD
International Classes:
G01F1/68; G01F1/696; G01F7/00; (IPC1-7): G01F1/68
Domestic Patent References:
| JPH02161313A | 1990-06-21 | |||
| JPH01308921A | 1989-12-13 | |||
| JPS6066116A | 1985-04-16 | |||
| JPS6255519A | 1987-03-11 | |||
| JPS63128425U | 1988-08-23 |
Attorney, Agent or Firm:
Masaki Yamakawa (3 outside)