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.
Variable area flowmeter (equal pressure drop flowmeter)
The float placed in the upper and lower small tapered flow passages is moved by the force of the fluid flowing from the bottom to the top. When this force is balanced with the "display weight" of the float (the weight of the float itself minus the buoyancy of the fluid it receives), the capture is stationary. The height at which the float is stationary can be used as a measure of the flow rate. Since the cross-sectional area of ??the flowmeter varies with the height of the float, and the pressure difference between the upper and lower parts is equal when the float is stationary, the flowmeter is called a variable area flowmeter or an equal pressure dropmeter. A typical instrument of this type of flow meter is a rotor (float) flow meter.
A flowmeter weighing flowmeter that uses the momentum of a measuring fluid to reflect the flow rate. Since the momentum P of the flowing fluid is proportional to the density of the fluid and the square of the flow velocity v, i.e., p v2 , when the flow cross section is determined, v is proportional to the volumetric flow rate Q, so p Q2 . Set the proportional coefficient to A, then Q=A. Therefore, P is measured to reflect the flow rate Q. In this type of flowmeter, most of the flowmeters are used to convert momentum into pressure, displacement or force, and then the flow rate is measured. Typical meters for such flow meters are target and rotary wing flow meters.
ltrasonic flowmeter installation
The time difference ultrasonic flowmeter is a competitive flow measurement method in the world today, and its measurement line accuracy is higher than 1.0%. Due to the diversity of the industrial site, especially the environment around the pipeline, how to install and debug the ultrasonic flowmeter according to the specific environment has become an important topic in the field of ultrasonic flow measurement. This procedure explains the installation details of the ultrasonic flowmeter; It further fully demonstrates the advantages of accuracy, reliability and stability of the ultrasonic flowmeter, greatly reducing future maintenance work and even maintenance-free.
Ultrasonic flowmeters should be aware of the site prior to installation, including:
1. What is the distance from the host at the installation of the sensor;
2. Pipe material, pipe wall thickness and pipe diameter;
3. Year of the pipeline;
4. Type of fluid, whether it contains impurities, bubbles, and whether it is full;
5. Fluid temperature
6. Whether there is interference source at the installation site (such as frequency conversion, strong magnetic field, etc.);
7. The temperature of the four seasons at the host site;
8. Whether the power supply voltage used is stable;
9. Whether remote signals and types are required;
According to the site conditions provided above, the manufacturer can configure the site conditions and, if necessary, special models.