Selection of Turbine Flow Meter
The correct selection of the turbine flowmeter can ensure the better use of the turbine flowmeter. What kind of turbine flow meter to choose should be determined according to the physical and chemical properties of the measured fluid medium? Make the diameter, flow range, lining material, electrode material and output current of the turbine flowmeter adapt to the nature of the measured fluid and flow measurement requirements.
Precise functional inspection
Accuracy grades and functions Choose the accuracy grade of the instrument according to the measurement requirements and usage occasions to achieve economical results. For example, when it is used for trade settlement, product handover and energy measurement, you should choose a higher accuracy level, such as 1.0 level, 0.5 level, or higher level; for process control occasions, choose different accuracy levels according to the control requirements; some are only It is to detect the process flow without precise control and measurement. You can choose a slightly lower accuracy level, such as 1.5, 2.5, or even 4.0. At this time, you can choose a low-cost plug-in turbine flow meter.
Measuring medium flow velocity, instrument range and caliber When measuring general medium, the full-scale flow rate of the emerson turbine flow meter can be selected within the range of 0.5-12m/s for measuring medium flow velocity, and the range is relatively wide. The selection of instrument specifications (diameter) is not necessarily the same as that of the process pipeline. It should be determined whether the measurement flow range is within the flow velocity range. That is, when the pipeline flow velocity is too low to meet the requirements of the flow instrument or the measurement accuracy cannot be guaranteed at this flow velocity It is necessary to reduce the caliber of the instrument, so that the flow rate in the tube can be satisfied with the measurement results.
1. According to the requirements of measurement purpose:
It is required to choose whether to have instantaneous flow or cumulative flow (cumulative flow), flow display unit, measurement accuracy, repeatability, linearity, flow range and range degree, measurement temperature, pressure loss, temperature and pressure compensation, output signal characteristics and response time wait. Different measurement objects have their own measurement purposes, and have different emphases in terms of performance.
2. Requirements for the nature of the measuring medium:
Chemical corrosion and fouling, the chemistry of the fluid sometimes becomes a determining factor in the choice of measurement method and instrumentation. Certain fluids can cause corrosion of instrument contact parts, surface fouling or precipitation of crystals on the metal surface to produce electrolytic chemistry.
3. Requirements for measuring medium phase composition:
Depending on whether the measured medium is a single phase change medium or multiphase and multicomponent flows should be treated with caution. Measuring a single clean medium, the electromagnetic flow meter can measure solid-liquid two-phase mixed media, etc.
4. Compression system and other parameter requirements:
Measuring gas needs to know the value of the compressibility coefficient in order to obtain the fluid density under working conditions. For fluids with fixed composition, the density is calculated through pressure, temperature and compressibility; for fluids with variable composition and working near (or in) the supercritical region, online measurement of density should be considered.
5. Measurement accuracy requirements:
The overall measurement accuracy requirements need to be clarified and whether it is used at a specific flow rate or varies significantly over the flow range due to temperature and pressure changes, the values are generally low and the differences between the various gases are small. The commonly used accuracy grades are grade 1.0 and grade 0.5. The accuracy grade of the turbine flowmeter is higher than that of the general rotor flowmeter. It is a good choice for customers with higher accuracy requirements.