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1. What is the internal structure of an electromagnetic flowmeter?
The core structure of an electromagnetic flowmeter is divided into five key parts, each of which performs its own duties to complete flow measurement. A measuring tube is a channel through which fluid passes, usually made of non-magnetic, low conductivity, low thermal conductivity, and sufficient mechanical strength materials such as stainless steel and fiberglass, which can ensure smooth fluid flow without interfering with the measured magnetic field. 2. There is usually a pair of electrodes installed on the inner wall of the measuring tube in direct contact with the measured fluid, and their function is to extract an induced potential signal proportional to the flow rate. The electrode material needs to be selected according to the properties of the fluid, and common ones include stainless steel, hafnium alloy, etc.
3. The excitation coil is responsible for generating a working magnetic field. By passing direct current or alternating current, a uniform magnetic field is formed, allowing the flowing conductive liquid to cut the magnetic field lines, thereby generating induced electromotive force
4. The magnetic yoke is made of materials with good magnetic conductivity, which are disassembled and used to gather the magnetic field generated by the excitation coil, reduce magnetic leakage, improve magnetic field utilization, and ensure the accuracy of measurement results
5. The converter amplifies, converts, and processes the weak induced electromotive force signals detected by the electrode, and finally outputs standard electrical signals such as 4-20mA current signals and pulse signals, which are convenient and efficient.
2. Calculation of flow rate in electromagnetic flowmeter, please explain?
Electromagnetic flowmeter: based on Faradays law of electromagnetic induction to measure the state flow rate U=B * L * vU - induced electromotive force B - magnetic field strength L - conductor length v - conductor velocity The coil formed by copper wire generates an alternating magnetic field bundle B. The controlled current ensures that the magnetic field strength remains constant throughout the measurement process.. The length of the conductor, denoted as L (the distance between the two measuring electrodes on the inner diameter of the measuring tube), is a constant. The only variable in the equation is the flow velocity v of the fluid. The instrument can directly measure the induced voltage between the electrodes, which is linearly proportional to the fluid diversion velocity U~v. Then calculate the flow rate, and the electromagnetic flowmeter measures not the volume but the flow rate Flow rate converted to volumetric flow rate: Q=v * AQ - volumetric flow rate v - liquid flow rate A - flowmeter cross-sectional area. From this, the volumetric flow rate of the liquid in the pipeline is calculated. (Above content copied from the instruction manual of Shanghai Xinxiang Technology Co., Ltd. NDFT electromagnetic flowmeter)
3. Working principle of electromagnetic flowmeter
Electromagnetic flowmeter works based on Faradays law of electromagnetic induction. When a conductive liquid cuts magnetic field lines in a magnetic field, it generates induced electromotive force. Electromagnetic flowmeter mainly consists of two parts: sensor and converter. Sensor part: