Installation of E+H electromagnetic flowmeters

The E+H electromagnetic flowmeter is formulated based on Faraday's law of electromagnetic induction and is used to measure the volume flow of conductive fluids. Due to its unique characteristics, it has been widely used in the measurement of various conductive liquids in industry. It is mainly used in chemical industry, papermaking, food, textile, metallurgy, environmental protection, water supply and drainage and other industries. It can realize system control when matched with computers. The E+H electromagnetic flowmeter has no moving parts and no flow blocking parts, which will not cause pressure loss, nor will it cause wear, blockage and other problems. It is a volume flow measuring instrument that is not affected by the temperature, viscosity, density and conductivity (within a certain range) of the medium being measured during the measurement process.

Installation of E+H electromagnetic flowmeter 1. Issues that need to be paid attention to during installation. Installation issues have different requirements for flowmeters with different principles. For some flowmeters, such as differential pressure flowmeters and velocity flowmeters, regulations require a certain length or longer straight pipe sections upstream and downstream of the flowmeter to ensure that the fluid flow in front of the inlet of the flowmeter reaches full development. . Other flowmeters, such as volumetric flowmeters and float flowmeters, have no or low requirements for the length of the straight pipe section. There are also flow meters that have certain errors due to the influence of installation. For example, Coriolis mass flow meters will cause large errors in use due to the influence of installation stress. When problems occur during the use of traceable flow meters, they may not necessarily be due to problems with the flow meter itself. Many problems are caused by poor installation. Generally common problems include the following: ① Install the inlet surface of the differential pressure flow meter orifice plate upside down; ② The flow sensor is installed in a place with poor flow velocity distribution profile; ③ There is an undesirable presence in the pressure pipe connected to the differential pressure device. existing phase; ④ The flow meter is installed in a harmful environment or an inaccessible place; ⑤ The flow meter is installed in the wrong direction; ⑥ The flow meter or electrical signal transmission line is placed under a strong electromagnetic field; ⑦ The flow meter that is susceptible to vibration interference is installed in a On pipes with vibration; ⑧ Lack of necessary protective accessories. 2. Installation conditions When using the E+H electromagnetic flowmeter, attention should be paid to the adaptability and requirements of the installation conditions. Mainly consider the following aspects, such as the installation direction of the flowmeter, the flow direction of the fluid, the configuration of upstream and downstream pipelines, and valves. location, protective accessories, effects of pulsating flow, vibration, electrical interference and maintenance of flow meters, etc. ① On-site pipeline wiring When wiring on-site pipelines, attention should be paid to the installation direction of the flow meter. Since the installation direction of the flow meter is generally divided into vertical installation and horizontal installation, there is a difference in flow measurement performance between these two installation methods. For example, the vertical downward flow of fluid will bring extra force to the flowmeter sensor, which will affect the performance of the flowmeter and reduce the linearity and repeatability of the flowmeter. The installation direction of the flow meter also depends on the physical properties of the fluid. For example, solid particles may precipitate in horizontal pipes, so flow meters measuring this state are installed in vertical pipes. ② Fluid flow direction This problem is similar to the installation direction of the flow meter. Since some flow meters are stipulated to only work in one direction, reverse flow will damage the flow meter. Also consider using similar flow metersReverse flow may occur when no operation occurs, which may require measures such as installing a check valve to protect the flow meter. Even a flowmeter that can be used in both directions may have some differences in measurement performance between forward and reverse directions and should be used in accordance with the requirements specified by the manufacturer. ③ In the straight pipe section upstream and downstream of the flow meter, the flow E+H electromagnetic meter will be affected by the flow state of the pipeline inlet, and the pipe fittings will also introduce flow disturbances. Flow disturbances generally include vortices and flow velocity distribution profile distortion. The existence of vortices is generally due to Caused by two or more spatial (three-dimensional) bends. Flow profile distortion is usually caused by local obstructions in pipeline fittings (such as valves) or bends. These effects need to be ameliorated with an appropriate length of upstream straight pipe section or the installation of a flow regulator. In addition to considering the influence of the flow meter connection accessories, the influence of the combination of upstream pipe fittings may also be considered, because they may produce different sources of disturbance, so the distance between the sources of disturbance must be maximized to reduce their influence. For example, a single elbow followed by a partially open valve. A straight pipe section is also required downstream of the flow meter to reduce the influence of downstream flow. Volumetric flowmeters and mass flowmeters are not affected by asymmetric flow profiles; turbine flowmeters should be used to reduce vortices as much as possible; E+H electromagnetic flowmeters and differential pressure flowmeters should limit vortices to a small range. Inside. Air pockets and condensation are caused by improper pipe layout. Avoid drastic changes in pipe diameter and direction. Poor piping layout can also produce pulsations. ④Pipe diameter and pipe vibration Some types of flowmeters do not have a very wide range of pipe diameters, so being too large or too small will limit the choice of flowmeter varieties. To measure the flow rate of low flow rate or high flow rate, you can choose a flowmeter pipe diameter different from the pipe diameter, and use a reducer to connect it to make the flow meter operate within the specified range. If the flow rate exceeds the range, if the flow rate is too low, the flow meter error will increase and the flow meter will not work. If the flow rate is too high, the flow meter error may also increase. At the same time, the flow sensor will overspeed or the pressure drop will be too large, damaging the flow meter. Some flowmeters, such as vortex flowmeters with piezoelectric detection components and Coriolis mass flowmeters, are sensitive to mechanical vibration and are easily disturbed by pipe vibration. Care should be taken to design supports for the pipes before and after the flowmeter. In addition to using pulsation eliminators to eliminate the effects of pulsation, it is also important to note that all installed flow meters should be away from sources of vibration or pulsation. ⑤The installation position of the valve. The pipes where the E+H electromagnetic flowmeter is installed are equipped with control valves and isolation valves. In order to avoid some flow velocity distribution disturbances and cavitations caused by the valves that affect the flowmeter measurement, the control valve should generally be installed at the flowmeter. Downstream, the control valve installed downstream of the flow meter can also increase the back pressure of the flow meter and reduce the possibility of air pockets inside the flow meter. The purpose of installing the isolation valve is to isolate the flow meter from the fluid in the pipeline for easy maintenance. The upstream valve should be sufficiently far away from the flow meter. When the flow meter is running, the upstream valve should be fully open to avoid disturbances such as flow velocity distribution distortion. ⑥ Protective accessories Installing protective accessories is a protective measure to ensure the normal operation of the E+H electromagnetic flowmeter. For example, in volumetricFlowmeters and turbine flowmeters generally need to install some necessary equipment such as filters upstream. All these equipment must be installed so as not to affect the use of the flowmeter. ⑦Electrical connection and electromagnetic interference At present, most flow measurement systems, whether it is the E+H electromagnetic flowmeter itself or its accessory connections, have electronic equipment, so the power supply used must be matched with the flowmeter. When the flow meter output level is low, a preamplifier adapted to the environment should be used. The output signals of some types of flow meters are easily interfered by high-power switching devices, causing the flow meter output pulse fluctuations and affecting the performance of the flow meter. For example, signal cables should be kept as far away from power cables and power sources as possible to reduce electromagnetic interference and radio frequency interference. Influence. ⑧ Pulsating flow and unsteady flow As mentioned before, in addition to using a pulsation eliminator for the impact of pulsating flow, attention should also be paid to keeping all installed flow meters away from the pulsation source. Common sources of pulsation include hydraulic oscillations such as fixed displacement pumps, reciprocating compressors, oscillating valves or regulators, and vortex columns. Generally, differential pressure flowmeters have pulsating flow errors, and turbine flowmeters and vortex flowmeters also produce pulsating flow errors. Unsteady flow refers to flow that changes with time and slow pulsation is a special case of unsteady flow. Such as the slow pulsation caused by the operation of an oversized control valve. The flow meter can handle the pulsation effects of the flow sensor and the secondary display instrument separately. Install the flow sensor away from the source of pulsation. You can also install low-pass filters such as gas buffers (for liquids) or chokes (for gases) in the piping system to reduce the degree of pulsation. For secondary display instruments, you can choose a flowmeter with good response characteristics (such as electromagnetic flowmeter, ultrasonic flowmeter) to increase damping, and measure the pulsation parameters to estimate the additional error of the pulsation.