『Punch plate 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. What are the representation methods of various types of flow meters in PID flowcharts?
The common representation methods of flow meters in P&ID (Process Piping and Instrument Diagram) are mainly distinguished by exclusive graphic symbols combined with instrument tag numbers. The specific explanations of the four mainstream flow meters are as follows: 1 Orifice flowmeter symbol: Represent the orifice plate with a rectangular shape, connect the pipeline lines at both ends of the rectangle, and label the corresponding instrument tag number on the side. Working logic: It belongs to a throttling flowmeter. When the fluid passes through the orifice plate, a pressure difference will be generated. The flow value can be converted by measuring the pressure difference.
2. Turbine flowmeter symbol: represented by a circular symbol with blades, with the corresponding instrument tag number marked on the side. Working logic: The fluid impacts the turbine blades to rotate, and the turbine speed is proportional to the fluid flow rate. Flow data can be obtained by detecting the speed. Electromagnetic flowmeter symbol: represented by a rectangular or circular symbol with electrodes, with corresponding instrument tag numbers marked on the side. Working logic: Based on the principle of electromagnetic induction, when a conductive liquid flows through a magnetic field, an induced electromotive force is generated. The flow rate can be determined by measuring the electromotive force.
4. Vortex flowmeter symbol: represented by a symbol with a vortex pattern, with the corresponding instrument tag number marked on the side. Working logic: When a fluid flows through a vortex generator, periodic vortices are generated, and
2. Orifice flowmeter and fluid direction
The fluid direction of the orifice flowmeter must be installed correctly, otherwise it will significantly affect the measurement accuracy and may damage the equipment.
. 1. Proper installation requirements: When installing an orifice flowmeter, it is necessary to strictly distinguish the direction of fluid flow: - The side of the orifice with a sharp edge (sharp edge) must face the direction of fluid flow, that is, fluid flows in from the sharp edge and flows out from the blunt edge; -This direction is based on the Bernoulli equation for design calibration, ensuring a stable pressure difference is formed before and after the orifice plate, making the flow calculation formula valid.2. The influence of reverse fluid flow. If the fluid direction is reversed, two typical problems will occur: • Measurement errors accompanied by a sharp increase in errors: reverse flow destroys the flow field distribution of the conical diffusion section behind the orifice plate, and the measured pressure difference cannot correspond to the standard flow calculation curve;
; • Risk of structural damage: Long term reverse erosion can lead to blunting of sharp edges, deformation of orifice plates, and in extreme cases, may cause cracking at the welded parts of the body. Having understood this principle, maintenance personnel should pay special attention to installing directional signs. Some high-end models will be marked with flow arrows on the flange surface, while conventional products will be identified through the thin blade feature that can be disting
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