| 摘要 |
PURPOSE:To detect a drift state caused by a decrease in the quantity of the fluid in a measurement pipe by providing the 3rd electrode under the measurement pipe in addition to main electrodes. CONSTITUTION:Exciting coils 4 and 5 are arranged on and under the measurement tube 1, and a couple of main electrodes P1 and P2 are arranged in its horizontal direction. The 3rd electrode P3, on the other hand, is arranged under the measurement pipe 1. Switches S1-S3 select outputs of the respective electrodes at a specific period. An A/D converter A/D1 inputs measured values of the electrodes P1 and P2 to CPU, and an A/D converter A/D2 inputs the ratio of output voltages between the electrodes P1 and P3, and P2 and P3 to the CPU. When the fluid in the measurement pipe 1 decreases in quantity to enter a draft state, the output of the converter A/D2 becomes smaller than 1, so this result is utilized to report the formation of space in the measurement pipe 1. Further, an accurate flow rate is calculated by utilizing said result as a correcting value. |
