| 摘要 |
PURPOSE:To detect a small flow rate of leakage on the downstream side, by opening a low different type opening/closing valve at an inlet or outlet of a measuring section smaller in the injection nozzle among measuring sections only when the pressure on the downstream side is lower than a set value on the upstream side. CONSTITUTION:A Reduced part 2 of a pipe line, an injection nozzle 3 and an expanded part 5 of the pipe line are arranged in order to form a meter. A pair of control nozzles 6a and 6b are formed on the bundle of the nozzle 3 and the expand section 5 roughly at a right angle to the injecting direction of the nozzle 3 while facing each other. Then, two measuring sections (A) and (B) are connected in series with a pair of feed back passages 7a and 7b formed to connect each of the nozzles 6a and 6b to the downstream side of the expanded part 5. A nozzle 3 at a measuring section (A) is formed with the smaller opening area than a measuring section (B). In addition, a bypass 15 detouring the measuring section (A) is connected to the measuring section. (B) and a diaphragm type governer valve (C) is provided in the bypass 15. In such a manner that the differential pressure between the pressure (P) on the upstream side and the pressure (P) on the downstream side will be maintained in a set range confined to a fixed flow rate range. The opening/closing valve (D) of the measuring section (A) is opened when the differential pressure is below a set value. |
