| 摘要 |
PURPOSE:To accurately measure a minute flow rate by obtaining a wave form signal having large amplitude and a well-regulated wave form, by arranging a pressure sensor for measuring a flow rate so as to detect the pressure change in the reversal flow part provided to the inlet of a return flow passage. CONSTITUTION:Flow passage forming members 4a, 4b forming a pipeline contraction part 2 and a jet nozzle 3 are arranged in a pipe 1 so as to be symmetric with respect to the center axis P of the pipe 1. Further, partition walls 8a, 8b forming return flow passages 7a, 7b allowing the downstream side of a pipeline enlarged part 5 to separately communicate with control nozzles 6a, 6b are arranged so as to be symmetric to the axis P. Then, the pipes 13a, 13b allowed to separately communicate with the reversal flow parts A at the inlet of the return passages 7a, 7b are connected to the hermetically closed case 16 arranged in a confluent discharge pipe 10 and a pressure sensor 14 is mounted in the case 16 so that the fluid pressures from the pipes 13a, 13b act in reverse directions to each other. The pressure change in the flow parts A is detected by the sensor 14 to send a sine wave like wave form signal to a flow rate measuring device 15 and a flow rate is calculated from the frequency of the wave form signal. By this method, a minute flow rate can be accurately measured. |
