MEASURING METHOD OF FLOW RATE IN PIPE FOR BROAD RANGE

摘要

PURPOSE:To enable to measure the flow rate for the broad range precisely by outputting the flow rate in a main pipe when said flow rate exceeds the specified value, and outputting the estimated flow rate depending on the computation based on the signals from the headers of a plurality of branch pipes which are selectively shut out when said flow rate is lower than the specified value. CONSTITUTION:The flow rate in the main pipe 11 is converted by a pressure difference oscillator 6 as the pressure difference at an orrifice 5, and supplied to a learning device 19 and a judging device 17 via an evolution device 7. The pressure at a header 3 which supplies the fluid in the main pipe 11 to a plurality of the branch pipes is measured by a pressure oscillator 14 and the result is applied to the learning device 19 and an operating device 16. A burner shut out control device 20 actuates an automatic burner shut off valve 18 by a flow rate command signal 9, so that the flow rate of the burner 4 does not decrease below the specified value. The judging device 17 supplies the flow rate of the main pipe when the flow rate is larger than the set value 21; and supplies the estimated value computed by the operating device 16 when the flow rate is smaller. Therefore the precise measurement can be performed even the flow rate is small.