LDG-40 LDG-50 LDG-65 LDG-80 Magnetic flowmeter

LDG-40 LDG-50 LDG-65 LDG-80 Magnetic flowmeter

Overview of LDG-40 LDG-50 LDG-65 LDG-80 Magnetic flowmeter

The structure of electromagnetic flowmeter is mainly composed of magnetic circuit system, measuring conduit, electrode, shell, lining and converter.
Magnetic circuit system: its function is to produce uniform DC or AC magnetic field. The DC magnetic circuit is realized by permanent magnet, which has the advantages of simple structure and less interference by AC magnetic field, but it is easy to polarize the electrolyte liquid in the measuring catheter, so that the positive electrode is surrounded by negative ions, and the negative electrode is surrounded by positive ions, that is, the polarization phenomenon of the electrode, which leads to the increase of internal resistance between the two electrodes, which seriously affects the normal operation of the instrument. When the pipe diameter is large, the permanent magnet is also large, bulky and uneconomical, so the electromagnetic flowmeter generally adopts alternating magnetic field and is excited by 50Hz power frequency power supply.

Measuring catheter: its function is to let the measured conductive liquid pass through. In order to make the magnetic flux shunted or short circuited when the magnetic force line passes through the measuring conduit, the measuring conduit must be made of materials with non-magnetic conductivity, low conductivity, low thermal conductivity and certain mechanical strength. Non-magnetic stainless steel, FRP, high-strength plastic, aluminum, etc. can be selected.
Electrode: its function is to lead out the induced potential signal proportional to the measured. Electrodes are generally made of non-magnetic stainless steel and are required to be flush with the lining so that the passage of fluid is not obstructed. Its installation position should be in the vertical direction of the pipeline to prevent sediment from accumulating on it and affecting the measurement accuracy.

Shell: made of ferromagnetic material, it is the outer cover of the distribution system excitation coil and isolates the interference of external magnetic field.
Lining: there is a complete layer of electrical insulation lining on the inner side of the measuring conduit and the flange sealing surface. It is in direct contact with the measured liquid. Its function is to increase the corrosion resistance of the measuring conduit and prevent the induced potential from being short circuited by the pipe wall of the metal measuring conduit. The lining materials are mostly corrosion-resistant, high temperature resistant and wear-resistant Teflon plastics, ceramics, etc.

Converter: the induced potential signal generated by liquid flow is very weak and greatly affected by various interference factors. The function of the converter is to amplify and convert the induced potential signal into a unified standard signal and suppress the main interference signal. Its task is to amplify and convert the induced potential signal ex detected by the electrode into a unified standard DC signal.

Working principle

The working principle of LDG-40 LDG-50 LDG-65 LDG-80 Magnetic flowmeter is a flowmeter for flow measurement according to Faraday's law of electromagnetic induction.

Features of LDG-40 LDG-50 LDG-65 LDG-80 Magnetic flowmeter

1. The measurement is not affected by the changes of fluid density, viscosity, temperature, pressure and conductivity;
2. There are no flow blocking parts and pressure loss in the measuring pipe, and the requirements for straight pipe section are low. Unique adaptability to slurry measurement;
3. Reasonably select the sensor lining and electrode material, that is, it has good corrosion resistance and wear resistance;
4. The converter adopts novel excitation mode, with low power consumption, stable zero point and high accuracy. The flow range can reach 150:1;
5. The converter can be integrated or separated with the sensor;
6. The converter adopts 16 bit high-performance microprocessor, 2x16lcd display, convenient parameter setting and reliable programming;
7. The flowmeter is a two-way measurement system with three integrators installed inside: forward total amount, reverse total amount and difference total amount; It can display positive and negative flow, and has a variety of outputs: current, pulse, digital communication, Hart;
8. The converter adopts surface mount technology (SMT), with self inspection and self diagnosis functions;
9. The measurement accuracy is not affected by the changes of fluid density, viscosity, temperature, pressure and conductivity. The sensor induced voltage signal has a linear relationship with the average flow rate, so the measurement accuracy is high.
10. There is no choke in the measuring pipeline, so there is no additional pressure loss; There are no movable parts in the measuring pipe, so the service life of the sensor is very long.
11. Because the induced voltage signal is formed in the whole space full of magnetic field and is the average value on the pipe load surface, the straight pipe section required by the sensor is short and the length is 5 times the pipe diameter.
12. The converter adopts the latest and most advanced single chip microcomputer (MCU) and surface mount technology (SMT), with reliable performance, high precision, low power consumption, stable zero point and convenient parameter setting. Click the Chinese LCD to display the cumulative flow, instantaneous flow, flow rate, flow percentage, etc.
13. Two way measurement system can measure forward flow and reverse flow. Special production technology and high-quality materials are adopted to ensure that the performance of the product remains stable for a long time.

Main tech data of LDG-40 LDG-50 LDG-65 LDG-80 Magnetic flowmeter

Diameter: DN10-DN2000 (mm) special can be customized

Nominal pressure: 0.6-4.0MPa (distinguished by caliber, special high pressure can be customized
Electrode material: 316L stainless steel, Hastelloy C, Hastelloy B, titanium, tantalum, platinum-iridium electrodes
Protection class IP65, IP67, IP68
Working power 220VAC, 24VDC
Current output 4~20mA
Communication interface RS232, RS485 (MODBUS-RTU) HART
Flange connection GB9119 (can be directly connected with pipeline flanges such as HG20593-1997) or according to customer requirements.
Environmental requirements -25℃~+60℃