The correct selection of turbine flowmeters can ensure better use of turbine flowmeters. What kind of turbine flowmeter should be selected according to the physical and chemical properties of the fluid medium to be tested? The diameter, flow range, lining material, electrode material and output current of the turbine flow meter can be adapted to the fluid to be measured. Nature and flow measurement requirements.
1, precision function check
Accuracy levels and functions are based on measurement requirements and usage scenarios to select instrument accuracy levels for cost-effectiveness. For example, in the case of trade settlement, product handover and energy measurement, the accuracy level should be higher, such as 1.0, 0.5, or higher; for process control, select different accuracy levels according to control requirements; It is to detect the process flow, no need to do precise control and measurement, you can choose a lower accuracy level, such as 1.5, 2.5, or even 4.0, then you can use a low-cost plug-in turbine flowmeter.
2, measurable medium
Measuring medium flow rate, meter range and caliber When measuring a general medium, the full flow rate of the turbine flow meter can be selected within the range of 0.5-12 m/s of the measured medium flow rate, and the range is relatively wide. The instrument specification (caliber) is not necessarily the same as the process pipe. It should be determined according to whether the measured flow range is within the flow rate range. That is, when the pipe flow rate is too low to meet the flow meter requirements or the measurement accuracy cannot be guaranteed at this flow rate, It is necessary to reduce the gauge diameter, thereby increasing the flow rate inside the tube and obtaining satisfactory measurement results. In order to ensure accurate measurement of the turbine flowmeter, the installation location and method must be correctly selected.
Requirements for straight pipe sections: The flowmeter must be installed horizontally on the pipeline (the pipeline is inclined within 5). The axis of the flowmeter should be concentric with the axis of the pipeline during installation, and the flow direction should be consistent. The length of the pipeline upstream of the flowmeter should have a straight pipe section of not less than 2D. If the installation site is sufficient, it is recommended that the upstream straight pipe section is 20D and the downstream pipe section is 5D.
Requirements for piping: The inner diameter of the upstream and downstream piping of the flowmeter installation point is the same as the inner diameter of the flowmeter.
Requirements for the bypass pipe: In order to ensure that the flowmeter does not affect the normal use of the medium during maintenance, a shut-off valve (stop valve) should be installed on the pipe before and after the flowmeter, and a bypass pipe should be installed. The flow control valve should be installed downstream of the flowmeter. When the flowmeter is in use, the upstream shut-off valve must be fully open to avoid unstable flow in the upstream part of the fluid.
Requirements for the external environment: The flowmeter is best installed indoors. When it is installed outdoors, it must be protected from sun, rain and lightning.