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Steps of how to use electromagnetic flowmeter calibration and calibration time

Electromagnetic flowmeter calibration time: every time measurement time should not less than device allows the shortest measuring time, shortest time generally shall be not less than 30 s, and the class A instrument (refers to the electromagnetic flowmeter with frequency output, plug-in electromagnetic flowmeter with A frequency output) should guarantee A verification of the flowmeter output pulse number were found in absolute value relative error is not more than 1/3 of the flowmeter repeatability.Assessment instrument performance when the general rules for calibration point: for class A instrument, calibration point should include qmin, 0.07 qmax and qmax 0.15, 0.25 qmax and qmax 0.4, 0.7 qmax and qmax, when after several calibration point flow is less than qmin, this calibration point can be neglected.For class B instrument (refer to output analog signal or can be directly display instantaneous flow of electromagnetic flowmeter), calibrating point should be at least five, including qmin and qmax check point, and uniform distribution.
The intelligent electromagnetic flowmeter calibration steps:
(1) according to the calibration experiment of pipe diameter and the size of the flow, choose the corresponding pump;
(2) if use compressed air to power system, open air compressor, air pressure meet the system requirements, to ensure the rapid switching of commutator and the normal work of the transceiver;
(3) flow meter installed correctly after on-line, shall, in accordance with requirements of the verification regulation of electricity preheating about 30 min;
(4) such as the high water tank, should check whether the overflow signal voltage towers to.Before the formal test, should be in accordance with the requirements of verification regulation with the verification medium in the pipeline  system cycle time, at the same time check the sealing parts in line with and without leakage phenomenon;
(5) before starting formal verification, should make verification medium detected flowmeter sensors, and downstream shutoff valve and zero adjustment;
(6) at the beginning of the test should be open front-end pipeline valve, slowly open the valve after checked flowmeter, flow to adjust the check point.
(7)All landowners in the process of calibration, the point of each traffic flow stability should be within 1% ~ 2% - flow method, and the total law can be within 5%.At the completion of a flow point of verification process verification medium temperature should be not more than 1 ℃, when complete verification process, should be no more than 5 ℃.Detected flowmeter downstream pressure should be high enough, in order to make sure the flow line (especially in reducing short) does not occur the phenomenon such as flash gas hole;
(8) after each test, shall, first of all, the trial line front end valve is closed, then stop the pump, so as to avoid empty will be regulated facilities.At the same time must take the rest of the verification of the test line of medium are empty, finally close control system and air compressor.



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| Updated:2015.10.29    Source:    Clicks:

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