Accuracy class and function According to the measurement requirements and the use occasions, the instrument accuracy level is selected to achieve economical efficiency. 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 electromagnetic flowmeter.
Measuring medium flow rate, meter range and diameter When measuring general medium, the full flow of electromagnetic flowmeter can be selected within the range of 0.5-12m/s of measuring medium flow, and the range is wider. The meter specification (caliber) is not necessarily the same as the process pipeline. It should be determined whether the measured flow range is within the flow rate range. That is, when the pipeline 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.
Try to avoid ferromagnetic objects and equipment with strong electromagnetic fields to prevent the magnetic field from affecting the working magnetic field and flow signal of the sensor.
Should be installed in the dry and ventilated place, to avoid sun and rain, the ambient temperature should be -20 ~ +60 ° C, relative humidity is less than 85%.
There should be ample space around the flowmeter for easy testing and maintenance.
Vortex flowmeter common fault
1. The measurement range of the vortex flowmeter is large, generally 10:1, but the lower limit of measurement is limited by many factors: Re>10000 is the most basic condition for the operation of the vortex flowmeter. In addition, it is also responded by the vortex. The signal, the vortex frequency f is also small, and it also makes signal processing difficult. The upper limit of measurement is the frequency response of the sensor and the frequency limit of the circuit. Therefore, the flow rate range must be calculated and calculated according to the flow rate of the fluid. The environmental conditions on the site are complicated. In addition to the conditions such as ambient temperature, humidity, and atmosphere, electromagnetic interference should also be considered.
2, vibration is also a big enemy of this type of instrument. Therefore, care should be taken to avoid mechanical vibrations, especially the lateral vibration of the pipe (perpendicular to the pipe axis and the vertical vortex generating body axis). This effect cannot be suppressed and eliminated in the design of the flowmeter structure. Since the vortex signal is equally sensitive to the influence of the flow field, it is not suitable for the length of the straight pipe section to ensure the flow conditions necessary for stabilizing the vortex street. Even the capacitive and ultrasonic type with strong anti-vibration performance guarantees that the fluid is a fully developed one-way flow, which is not negligible.
The medium temperature also has a great influence on the performance of the vortex flowmeter. For example, the pressure stress type vortex flowmeter cannot be used for a long time at 300 °C, because its insulation resistance is rapidly reduced from 10-100 MΩ at normal temperature to 1-101 Ω, and the output signal is also small, resulting in deterioration of measurement characteristics. In the measurement system, the sensor and the converter should be installed separately to avoid long-term high temperature affecting the reliability and service life of the instrument. The vortex flowmeter is a relatively new type of flowmeter. It is in the development stage and is not very mature. If it is not properly selected, the performance will not work well. Only after reasonable selection and correct installation, it is necessary to carefully and regularly maintain during the use process, accumulate experience, improve the predictability of system failure and the ability to judge and deal with problems, so as to achieve satisfactory results.
Ultrasonic Flowmeter Introduction and Features
Definition:
Ultrasonic flow meters are meters that measure the flow by detecting the effect of fluid flow on the ultrasound beam (or ultrasound pulse).
Principle:
According to the principle of signal detection, ultrasonic flowmeter can be divided into propagation velocity difference method (direct time difference method, time difference method, phase difference method and frequency difference method), beam offset method, Doppler method, cross correlation method, spatial filtering method. And noise law, etc.
Ultrasonic flowmeter is the same as electromagnetic flowmeter. It is an unobstructed flowmeter because it does not have any obstruction parts. It is a kind of flowmeter suitable for solving difficult flow measurement problems, especially in large-diameter flow measurement. The advantage is that it is one of the fastest growing types of flow meters.
Features:
Unique signal digital processing technology makes the meter measurement signal more stable, anti-interference ability and more accurate measurement.
No mechanical transmission parts are not easy to damage, maintenance-free and long life.
The circuit is more optimized and integrated; the power consumption is low and the reliability is high.
Intelligent standard signal output, friendly man-machine interface, multiple secondary signal output, for you to choose.
Pipe-type small pipe diameter measurement is economical and convenient, and the measurement accuracy is high.