Knowledge on the installation and procurement of sewage flow meters

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　　The main components of the sensor in a sewage flow meter are: the measurement tube, electrodes, excitation coil, core, and yoke housing. It is mainly used to measure the volumetric flow rate of conductive liquids and slurries in closed pipes. This includes highly corrosive liquids such as acids, bases, and salts. It is widely used in industries such as petroleum, chemicals, metallurgy, textiles, food processing, pharmaceuticals, and papermaking, as well as in fields like environmental protection, municipal management, and water conservancy construction. Today, the technical team from the manufacturer will provide users with a detailed overview of the installation of sewage flow meters and the considerations that need to be taken into account when selecting such meters:

Installation of sewage flow meters:
1. Selection of the installation environment for sewage electromagnetic flow meters: These meters should be installed as far away as possible from devices that generate strong electromagnetic fields, such as large motors, large transformers, and large frequency converters. The installation site should not experience severe vibrations, the pipes must be securely fixed, and there should be minimal fluctuations in ambient temperature. The installation environment should also facilitate easy installation and maintenance. 　　2. Selection of the installation location for electromagnetic flowmeters for wastewater: The installation location must ensure that the pipeline is always filled with the liquid to be measured; choose a spot where the fluid flow pulses are small, that is, away from pumps, valves, elbows, and other components that create local resistance; when measuring two-phase liquids (solid-liquid or gas-liquid), select a location where phase separation is unlikely to occur; the inner diameter or circumference of the pipeline to be measured should be easy to determine, and its ellipticity should be low. 　　3. Length of the straight pipe section for electromagnetic flowmeters in wastewater systems: The length of the straight pipe section on the upstream side of the pipeline where the sensor is installed should be greater than or equal to 10D, while it should be at least 5D on the downstream side (D being the diameter of the pipeline being measured). 　　4. Flow control valves and regulating valves: Flow control valves should be installed on the pipeline being measured, on the upstream side of the sensor, while flow regulating valves should be installed on the downstream side of the sensor; during flow operation, the flow control valve should usually be in its fully open position. 　　Considerations for selecting wastewater flow meters: 1. We need to know what type of factory wastewater is involved; this includes measuring wastewater from power plants, steel mills, chemical plants, as well as domestic wastewater. 　　2. It is necessary to know the components in the wastewater, its degree of corrosiveness, as well as whether there are any particles or debris present. It is to properly select the lining and electrode materials for electromagnetic flowmeters. If we are not very familiar with the composition of wastewater, we can indirectly determine its corrosiveness by understanding the material used in the wastewater pipes. When the wastewater has low corrosivity or is non-corrosive, an electromagnetic flow meter with stainless steel electrodes lined with PTFE can be used; whereas when the wastewater is highly corrosive, an electromagnetic flow meter with tantalum electrodes lined with PTFE is a better choice. 　　3. It is necessary to understand the parameters of the sewage pipeline’s diameter, minimum flow rate, normal flow rate, and maximum flow rate. Since each diameter of electromagnetic flowmeters has certain requirements regarding the minimum flow rate, when the flow rate is too low, it affects the measurement accuracy and leads to inaccurate readings. When the flow rate is too low, we generally reduce the diameter of the pipeline to meet the measurement requirements of the electromagnetic flowmeter. 　　4. It is necessary to understand the site environment where the flow meter will be installed, including the straight pipe section ahead and any existing interference at the site. Electromagnetic flowmeters require a certain length of straight pipe section in front of them during installation, as well as a site free from strong interference signals. There are also specific requirements regarding temperature and humidity at the installation site. 　　5. It is also necessary to understand the user’s requirements regarding the power supply for the instrument and its display method. If it is required that there be a display on-site, then an integrated electromagnetic flowmeter should be chosen; if the display from the meter needs to be sent to the control room, then a split-type electromagnetic flowmeter is appropriate. The length of the wires for a split-type electromagnetic flowmeter should preferably not exceed 100 meters, as otherwise it may affect the measurement accuracy. 　　Flow metering is one of the components of metrological science and technology, and it is closely related to the national economy, national defense construction, and scientific research. Doing this job well plays an important role in ensuring product quality, improving production efficiency, and promoting the development of science and technology. Especially in today’s era of energy crises and an increasing degree of automation in industrial production, the significance and role of flow meters in the national economy have become even more evident.