Requirements for straight pipe section of vortex flowmeter | Requirements for vertical installation of straight pipe section for measuring steam with vortex flowmeter

『Requirements for straight pipe section of vortex 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. Does installing elbows directly before and after the flowmeter have a significant impact? Installing elbows directly before and after the flowmeter can cause a decrease in measurement accuracy or even equipment damage. 1. Installation specifications: According to GB/T 20727-2006 "Measurement of Fluid Flow in Closed Conduits", sufficient straight pipe sections should be maintained before and after the flowmeter: - Front straight pipe section length: usually 10-15 times the pipe diameter (vortex street/turbine equal velocity flowmeter has the highest requirement) - Rear straight pipe section length: usually more than 5 times the pipe diameter. Elbows can disrupt the fluid flow state, cause flow velocity distribution distortion and vortex generation, directly violating the basic installation guidelines.

2 Specific Impact Performance 2.1 Decrease in Measurement Accuracy - Electromagnetic Flow Meter: Additional Error of ± 3% to ± 5% - Vortex Flow Meter: Interference with Vortex Generator May Cause Error of ± 10% or More - Ultrasonic Flow Meter: Signal Attenuation Caused by Sound Path Deviation 2.2 Equipment Damage Risk - Turboflow Meter: Bearing Accelerated Wear Due to Lateral Force - Mass Flow Meter: Zero Drift Caused by Abnormal Stress in Measuring Tube - Cavitation at Elbows Can Damage Electrodes/Liners (Electromagnetic Flow Meter) 3 If it is necessary to install an elbow in an emergency solution, the following compensation measures should be taken: - Install a flow regulator (porous plate or bundle type), which can shorten the straight pipe section to 3D - Use a flow field compensation algorithm built-in in the flowmeter (such as Emerson high-precision transmitter) - Install two double elbows on the vertical

plane behind the elbow to balance the flow field 4 Special case handling is limited to the following flow meters, and the straight pipe section can be appropriately shortened: - Coriolis mass flow meter Pi Shen: front 3D, back 2D (to be confirmed by the manufacturer) - Insertion flow meter: front 5D, back 3D (to be calibrated for flow field). The latest national standard GB/T 18659-2018 specifies that if the installation conditions do not meet the specifications of the grip beam, the measurement characteristics need to be recalibrated. In practical applications, the CNOOC Huizhou Refining and Chemical Project experienced measurement errors of thousands of tons per year due to insufficient elbow distance (case study in 2019).

2. Do vortex flowmeters have requirements for straight pipe sections?

Requirements for straight pipe section of vortex flowmeter, such as air raid interception

1. Straight pipe section requirements: In order to ensure the accuracy of vortex flowmeter, the length of the upstream straight pipe section should not be less than 15 times the nominal diameter (D) of the pipeline, and the length of the downstream straight pipe section should not be less than 5 times the nominal diameter of the pipeline

2. Shrinkage situation: In a reduced diameter pipeline, the length of the upstream straight pipe section of the vortex flowmeter should be at least 15 times the nominal diameter of the pipeline, and the length of the downstream straight pipe section should be at least 5 times the nominal diameter of the pipeline

3. Expansion situation: For an expanded pipeline, the length of the upstream straight pipe section of the vortex flowmeter should be at least 15 times the nominal diam

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