Seek the calibration method for double-flange transmitters
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Please explain the steps in detail, thank you
Place the two flanges at the same level, with their diaphragms facing each other but not touching each other; it is best to do this in a wind-free environment in order to zero the device
Let the differential pressure range of the double-flange differential pressure transmitter be from –A to B. 1. Use a set of calibrators for verification: (1) The two flange surfaces must be at the same horizontal level. By using a set of fixed values, do not apply signals to both diaphragm chambers of the transmitter; that is, divide –A to B into five equal parts and let the transmitter sense these five differential pressure values respectively. Check whether the transmitter’s output meets the requirements, and if it does not, make the necessary technical adjustments. (2) Lift the flange on the negative pressure side to a certain height so that the distance between the upper flanges is the same as in reality. The signal applied to the transmitter is the differential pressure resulting from the actual change in liquid level, namely 0~ρgH. If the zero point of measurement is located h0 above the lower flange, then the range of the signal applied at this time is ?ρgh0~?ρg(H+h0). 2. Verification using two setpoints: First, bring the two flange surfaces of the transmitter to the same horizontal level, and apply signals to these flanges using two setpoints. The signal applied to the negative pressure side is –A, and this value remains constant. Then a signal is applied to the positive pressure chamber, ranging from 0 to B+A, and the corresponding output signal is 4 to 20 mA
This is how we conduct the verification: during the shutdown period, if there is positive pressure, the pressure-sensing diaphragm is removed and a flange that can hold water is installed. 2 Fix the flange at its original height using bolts. 3 Add water to the actual school.
If it’s another liquid, just use the liquid you usually use for measurements.
This way, it can be compared with on-site display and DCS; once they match, that’s fine.