Thread Content
As a high-precision gas flow meter, the swirl vortex flowmeter is being increasingly used for measuring gases such as natural gas. Manufacturers of vortex flowmeters must calibrate them in accordance with the relevant calibration procedures (usually every 2 years) to ensure their measurement accuracy and reliability during use. During calibration, pressure readings are taken from the pressure tapping holes on the flowmeter itself to carry out compensation calculations. Vortex flowmeters are widely recognized by users in measurement applications. However, in actual production measurements, the natural gas being measured often contains impurities due to its impure composition, which can lead to blockages and corrosion in the pressure-taking holes of the flowmeter. This prevents proper pressure measurement during calibration. Some calibrators simply take pressure readings from these holes or refrain from doing so at all. What are the consequences of this? When the model of the swirl vortex flow meter is determined, the flow meter exhibits better linearity when calibrated using pressure sampling from the meter’s own pressure holes; however, its linearity is poorer when calibrated using pressure sampling from the pipes ； When the flow measurement points are the same, flow meters with pressure sampling from the gauge body exhibit smaller errors, while those with pressure sampling from the pipeline pressure holes have larger errors ； The errors caused by the two pressure sampling methods increase gradually as the flow rate rises; at a flow rate of 2900 m3/h, the difference between the two methods is nearly 6.2%, which far exceeds the accuracy level of the flow meter. Suggestions from spiral vortex flowmeter manufacturers for customers when using these devices: Without compromising the performance of the flowmeter, manufacturers can make appropriate improvements to its structure; for example, they can adjust the location of the pressure tapping holes to prevent them from getting clogged by debris. At the point of use, the user can install a filtering device at the front end of the rotameter to remove debris. When leaving the factory, the screws outside the pressure tapping hole of the rotameter are coated with lubricant, and the inside of the pressure tapping hole is sealed with a rubber plug to prevent debris from clogging it and to stop the hole from rusting. During the calibration of swirl vortex flowmeters, if there are significant variations in the point flow rate while the pressure change of the flowmeter is irregular, the calibration system should provide an alarm indicating that pressure measurement is invalid, so as to alert the calibrators to take appropriate corrective actions. For more information, please visit the company’s official website at http://www.yb1518.com/. Please keep this link when reproducing the content! http://www.yb1518.com/UploadFiles/20101022185438865.jpg