Flow measurement method and selection procedure of instrument

1 Determine whether you really want to install a flow meter. If you only want to know whether the fluid in the pipeline is flowing and its general flow, then you can use a flow viewing window or a flow indicator to achieve this goal at a lower cost. They are some simple devices, often there is a movable body (plate, ball, wing wheel, etc.) to show whether the fluid is flowing, and some can know the speed of the flow. 1 Determine whether you really want to install a flow meter. If you only want to know whether the fluid is in the pipeline Conveying flow, its general flow, then the use of flow viewing window or flow indicator can achieve this goal at a lower cost. They are some devices with simple structure. They often have a movable body (board, ball, wing wheel, etc.) to show whether the fluid is flowing, and some can know the general degree of the flow speed, the accuracy is very low, and the error is generally between 20-30%. Or bigger. The domestic flow meter manufacturing industry does not pay enough attention to the publicity of viewing windows and flow indicators. Only a few companies provide products, so design units and direct users ignore such simple appliances, or want to use them because of the single variety and cannot be used in multiple forms. Choose a co-use product. On the other hand, in the petrochemical complete sets imported from abroad, mobile viewing windows or indicators are installed in more workstations. If the measurement requirements are higher than the above and the indicated flow error is between 2-10%, install a flow meter. If you choose a differential pressure instrument according to the following selection steps, it is not necessary to install a flow sensor such as an orifice fluid. You can use an elbow flowmeter or use an external clamp to install a portable ultrasonic flowmeter. 2 Preliminary measurement and distribution After determining that a flow meter must be installed, learn more about the use requirements and various conditions in further detail. First, according to the type and characteristics of the fluid, take the measurement schemes that cannot and should not be used in the 'primary selection table' by the elimination method, and make the second step in-depth consideration and analysis. 3 Analyze factors according to the plans determined in the preliminary selection, collect samples, technical data and selection manuals from the manufacturers of the preliminary selection of meters to fully understand the specifications of the meters; and then according to the performance requirements and specifications of the meters, fluid characteristics, installation locations, Environmental conditions and economy consider five factors, analyze one by one, and compare the list.