Views: 2 Author: Site Editor Publish Time: 2022-07-06 Origin: Site
For the diversity of industrial flow measurement instrumentation equipment, we can choose to use different instrumentation equipment due to different application environments when using industrial instruments. So what is the difference between a turbine flow meter and a vortex flow meter?
1. The working principle is different
Turbine flow meter focuses on measuring liquid and belongs to velocity type flow meter. Mature high-precision instrumentation.
The vortex flow meter is designed and manufactured according to the principle of Karman vortex. The principle of fluid oscillation is used to measure the flow. When the fluid passes through the vortex flow transmitter in the pipeline, two rows of vortices proportional to the flow rate are alternately generated up and down behind the vortex generator of the triangular column. The average velocity of the fluid is related to the characteristics of the vortex generator.
2. Different characteristics
Features of turbine flow meter: high precision, good repeatability, simple structure, few moving parts, high pressure resistance, wide measurement range, small volume, light weight, small pressure loss, and easy maintenance.
The characteristics of vortex flow meter: small pressure loss, large measuring range and high precision. The vortex flow meter is hardly affected by parameters such as fluid density, pressure, temperature, viscosity, etc. when measuring the volume flow of the working condition. It has no moving mechanical parts, so it has high reliability and low maintenance. Instrument parameters can be stable for a long time.
3. Different application fields
Vortex flow meter: It is mainly used for flow measurement of medium and fluid in industrial pipelines, such as gas, liquid, steam and other media.
Turbine flow meter: widely used in the following measurement objects: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas, coal gas and cryogenic fluids and other aspects.
In the case of a complete understanding of the working conditions on site, you can choose a suitable flow meter for use. In some occasions for measuring liquid media, both vortex flow meters and turbine flow meters can be used. Both can be used without the interference of strong electromagnetic fields. The vortex flow meter cannot be used normally when the vibration is too large, and the viscosity of the medium is too high. When the viscosity is high and requires accurate measurement for long-term operation, it is not suitable to use the turbine flow meter, because the mechanical parts of the turbine flow meter are easy to wear and affect the accuracy. Periodic inspection, cannot be used for occasions that cannot be shut down.
In the case of a complete understanding of the on-site working conditions, a suitable flow meter can be selected for use. In some occasions for measuring liquid media, both vortex flow meter and turbine flow meter can be used. For example, both can be used when there is no excessive vibration on site and no interference from strong electromagnetic fields. The vortex flow meter cannot be used normally when the vibration is too large or the viscosity of the medium is too large. Turbine flow meters are not suitable for occasions with high viscosity that require accurate measurement during long-term operation, because the mechanical parts of turbine flow meters are easily worn, and the accuracy needs to be checked regularly.
4. Differences in data transmission
The turbine is the flow measurement obtained by cutting the magnetic field line through the rotation of the impeller to output the signal and then processing and outputting the signal.
Vortex is a flow measurement obtained by detecting Karman vortices and then processing the output signal.
1. Measuring medium. The measurement medium of the turbine flow meter can only be gas, and it can also be water, pure water, organic liquid, inorganic liquid and other liquids that do not contain fibers or particulate impurities. Because fibers, particles, impurities, etc. may entangle the turbine blades, causing damage to them, affecting the measurement accuracy, it may even stop rotating.
2. Pipe diameter. Unlike other flow meters, the diameter of turbine flow meters can be very small.
In terms of DN4, other flow meters generally can only reach DN15 or more. However, turbo flow diameter limit of the gauge is also very small. In theory, it can only be DN200, which can also meet most of the requirements on the market demand.
3. Measurement accuracy. The accuracy of the turbine flow meter also has several grades, the conventional ones are 0.5 and 1.0. These two levels can basically meet the needs of most industrial sites. However, in some occasions with higher precision requirements, higher grades are often required.
4. Medium viscosity. Turbine flow meters are not suitable for measuring liquids that are too viscous, otherwise it will affect the rotation of the impeller (in this case, it is more appropriate to use an oval gear flow meter). Theoretically speaking, the medium viscosity of the turbine flow meter should be less than 5x106m2/s (for the liquid larger than 5x10-6m2/s, the flow meter should be calibrated according to the actual liquid). In layman's terms, the viscosity should be smaller than that of cooking oil.
5. Nominal pressure. According to the current market demand, there are mainly 1.0Mpa, 1.6Mpa, 2.5Mpa, 4.0Mpa, 6.3Mpa.
6. Medium temperature. The main temperature range is -20℃~+120℃.
7. Power supply: 3.6V lithium battery, 12VDC, 24VDC.
1. Precise functional inspection
Accuracy class and function Select the instrument accuracy class according to the measurement requirements and application occasions, so as to be economical and cost-effective. For example, in the case of trade settlement, product handover and energy measurement, a higher accuracy level should be selected, such as 1.0, 0.5, or higher; for process control, different accuracy levels should be selected according to the control requirements; some 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 vortex flow meter.
2. Measurable medium
Measuring medium flow rate, instrument range and diameter When measuring general medium, the full-scale flow rate of the vortex flow meter can be selected within the range of 0.5-12m/s of the measured medium flow rate, and the range is relatively wide. The specification (diameter) of the selected instrument is not necessarily the same as that of the process pipeline. It should be determined according to whether the measurement flow range is within the range of the flow rate, that is, when the flow rate of the pipeline is too low to meet the requirements of the flow meter or the measurement accuracy cannot be guaranteed at this flow rate, It is necessary to reduce the diameter of the instrument to increase the flow rate in the pipe and obtain satisfactory measurement results.
3. Selection of vortex flow transmitter
The VA type piezoelectric vortex flow transmitter is used in the measurement of saturated steam. Due to the wide range of the vortex flow meter, in practical applications, the main consideration is that the flow rate of the saturated steam should not be lower than the vortex flow meter. The lower limit, that is to say, the fluid velocity must not be lower than 5m/s. Vortex flow transmitters with different diameters are selected according to the size of the steam consumption, and the diameter of the transmitter cannot be selected with the existing process pipe diameter.
4. Selection of pressure compensation pressure transmitter
Because the saturated steam pipeline is long and the pressure fluctuates greatly, pressure compensation must be used. Considering the corresponding relationship between pressure, temperature and density, only pressure compensation can be used in the measurement. Since the saturated steam pressure of the pipeline is in the range of 0.3-0.7MPa, the pressure The range of the transmitter can be selected as 1MPa.
5. Display instrument selection
Display instrument Intelligent flow display instrument, with voltage stabilization compensation, instantaneous flow display and cumulative flow accumulation functions.