What are the differences between steam orifice flowmeter | vortex flowmeter and orifice flowmeter when measuring steam? The senior staff of Qingtian Instrument is ..

『Steam orifice flowmeter』Related information(clamp on meter|electromagnetic meter|venturi meterrotameter|orifice meter|ultrasonic flow meter|mass flow meter|coriolis mass flow meter|coriolis flow meter|magnetic flow meter|magmeter flow meter|magflow flow meter|mag meter flow meter|electromagnetic flow meter|vortex flow meter|turbine flow meter|thermal mass flow meter|thermal flow meter|rotameter flow meter)

1. The reason for the slow decrease in flow rate of the orifice flowmeter is mainly related to five factors: blockage of the pressure tapping system, wear and deformation of the orifice plate, changes in process parameters, abnormal sales of pipeline working fluid, and improper maintenance of the instrument. Specifically, one issue is the blockage of the pressure sensing system. If there are impurities, crystals, or viscous substances in the medium, they will slowly deposit in the pressure sensing tube, causing the transmission of differential pressure signals to be obstructed and the flow display to decrease. For example, in a steam system, if a steam trap fails, condensed water freezes or impurities accumulate, the pressure sensing tube will be blocked; The pressure tapping hole is also easily blocked by particles, oil stains, or scaling in the medium, which makes it difficult to accurately transmit the actual differential pressure value to the transmitter, resulting in low flow display. The second issue is the wear and deformation of the orifice plate itself. Long term exposure to high-speed media can cause the aperture of the orifice plate to increase, especially at the edge of the throttle hole. According to the flow formula, changes in aperture will cause changes in the flow coefficient. When the actual flow rate remains constant, the displayed value will decrease; Under high temperature and high pressure conditions, the orifice plate may deform due to thermal stress or improper installation, such as exceeding the ellipticity limit, damaging the geometric shape of the throttling element, and causing distortion of the differential pressure signal. Thirdly, changes in process parameters, such as density, viscosity, temperature, or pressure of the medium deviating from the design values, can cause the flow coefficient and compressibility correction coefficient to deviate from the original set values. For example, gas flow rate is greatly affected by pressure and temperature, and parameter fluctuations can cause abnormal display of flow rate; The orifice plate design has the highest accuracy within a specific Reynolds number range. If the actual flow rate remains below the design lower limit for a long time, insufficient Reynolds number will make the flow coefficient unstable and the displayed value gradually decrease. The fourth issue is abnormal working conditions of the pipeline and accessories. Scaling on the inner wall of the pipeline will cause the diameter to decrease, and the flow rate will increase when the actual flow rate remains unchanged. However, the differential pressure of the orifice plate is proportional to the square of the flow rate. If scaling is severe and the flow rate exceeds the design range, the displayed value will decrease due to changes in the flow coefficient; Process equipment failures such as upstream valve jamming and reduced pump outlet pressure can directly cause a decrease in actual flow rate, and may also be accompanied by a synchronous decrease in differential pressure signals, which can easily be mistaken as an instrument problem. The fifth is that instrument maintenance and calibration should not be carried out simultaneously. After long-term use, the zero point or range of the differential pressure transmitter will drift, and irregular calibration can lead to measurement deviation of the differential pressure signal, thereby causing flow display errors; Loosening or corrosion perforation of

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