| 摘要 |
PURPOSE:To enable a pressure detector to be calibrated without being demounted by providing a calibrating pressure vessel and a calibrating line connected thereto. CONSTITUTION:A calibrating instrument is provided with a calibrating pressure vessel 32 that is so mounted as to airtightly cover a pressure transducer 28 and with a calibrating line 34 connected to the vessel 32. A normal measurement is conducted in a condition that a three-way valve 44 is opened to the side of an open conduit 46 and that the internal pressure of the vessel 32 is kept constant. This is because, if the transducer 28 was in a closed condition, the internal pressure of the vessel 32 would be changed by a change in temperature or the like to produce an error in the pressure being measured. After calibration data are made, the system to be measured of a plant or the like is provided with a pressure detector 16 having the calibrating instrument. When an inoperation calibrating test is conducted as the instrument is installed to the plant, a reference calibrating pressure is applied to a calibrating pressure conduit 42 from a calibrating pressurizer 48 and the value indicated by the detector 16 is read to make a calibration curve. By comparing the data thus obtained with calibration data that have been obtained in a primarily measured diaphragm pressure and calibrating the detector 16, a highly accurate calibration can be performed without dismounting the detector 16.
|
