The allowable error of a flow meter under specified normal working conditions is called the allowable error of the flow meter, which is generally expressed by relative error and reference error.
The allowable error of a flow meter under specified normal working conditions is called the allowable error of the flow meter, which is generally expressed by relative error and reference error.
The accuracy levels of flow meters are divided according to the allowable error. The accuracy levels are: 0.02, 0.05, 0.1, 0.2, 0.5, 1.0, 1.5, 2.5, etc.
The size of pressure loss is an important technical indicator for flow meter selection. The pressure loss is small, the fluid energy consumption is small, the power requirements for transporting fluid are small, and the measurement cost is low. On the contrary, the energy consumption will be large and the economic benefits will be reduced accordingly. Therefore, it is hoped that the pressure loss of the flow meter should be as small as possible.
1) The electromagnetic flowmeter is a volume flow measurement instrument. During the measurement process, it is not affected by the temperature, viscosity, density and conductivity (within a certain range) of the measured medium. Therefore, the electromagnetic flowmeter can be used to measure the flow of other conductive liquids only after being calibrated with water.
2) The output of the electromagnetic flowmeter is only proportional to the average flow velocity of the measured medium, and has nothing to do with the flow state (laminar flow or turbulent flow) under symmetrical distribution. Therefore, the measuring range of electromagnetic flowmeter is extremely wide, and its measuring range can reach 100:1, and some even reach the operational flow range of 1000:1.
3) The sensor structure of the electromagnetic flowmeter is simple. There are no movable parts in the measuring tube, and there are no throttling parts that hinder the flow of fluid. Therefore, when the fluid passes through the flow meter, it will not cause any additional pressure loss, and it is the most energy-consuming flow meter in the flow meter.
4) It can measure the flow rate of dirty media, corrosive media and suspended liquid-solid two-phase flow. This is because there are no flow-impeding parts inside the measuring tube of the instrument, and only the lining and electrodes of the measuring tube are in contact with the measured fluid, and their materials can be selected according to the properties of the measured fluid. For example, using polytrifluoroethylene or polytetrafluoroethylene as the lining can measure various corrosive media such as acids, alkalis, and salts; using wear-resistant rubber as the lining is particularly suitable for measuring wear and tear particles containing solid particles. Larger liquid-solid two-phase flows such as slurry and cement slurry, as well as various fibrous liquids and suspended liquids such as paper pulp.
5) The diameter range of industrial electromagnetic flowmeters is extremely wide, from a few millimeters to several meters, and there are real-flow calibration equipment with a diameter of 3m in China, which provides a good foundation for the application and development of electromagnetic flowmeters. laid the foundation.
6) The electromagnetic flowmeter has no mechanical inertia and is sensitive in response. It can measure instantaneous pulsating flow as well as flow in both forward and reverse directions.
Hangzhou Economic Development Area，Hangzhou 310018，China
