『Shanghai orifice flowmeter』Related information(v cone flow meter|rotary gas meter|gallon meter|gear meter|metal tube rotameter|glass tube rotameter|nutating disk meter|transit time ultrasonic flow meter|wedge flow meter|pd meters|hydraulic flow meter|ultrasonic water flow meter|water flow meter|air flow meter|magnetic water flow meter|oxygen flow meter|gas flow meter|argon flow meter|air velocity meter|gasoline flow meter|fuel flow meter|ultrasonic water meter|digital water meter|nitrogen flow meter|solid flow meter|Oxygen tank flow meter|digital water flow meter|diesel fuel flow meter|steam flow meter|02 flow meter|compressed air flow meter|oil flow meter|liquid flow meter)
1. Negative number displayed on the head of the orifice plate flowmeter
The negative number displayed on the orifice plate section flowmeter is usually caused by incorrect installation direction, reversed signal line connection, improper parameter settings, or pipeline backflow, and needs to be adjusted accordingly. 1. Installation issues: If the direction of the orifice plate is opposite to the actual flow direction of the fluid, it will result in negative measurement values. At this point, it is necessary to reinstall the orifice plate to ensure that the direction of the arrow marked on it is completely consistent with the fluid flow direction
2. Signal transmission problems may occur if the positive and negative poles of the signal line are reversed, which may cause reverse signal transmission. You can check the signal lines, especially the connection between the transmitter and the meter head, by referring to the wiring diagram. After confirming that the positive and negative poles correspond correctly, re fix them.
3. Instrument setting issues: If the flow direction and zero parameters set inside the instrument conflict with the actual situation, negative numbers may be displayed. You need to enter the parameter setting interface, calibrate the flow direction option according to the manual, and perform zero trace point correction if necessary. Abnormal fluid flow, pressure fluctuations in the pipeline, or pump valve operation errors may cause backflow. Suggest observing the process operation status and checking the logic of pump valve opening and closing; If backflow is frequent, check valves can be installed downstream to restrict reverse flow.
2. The reason for the slow decrease in f
. 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
Hot News
Related AD
