AOBO Metering, 4C Tower, North Side of Minzhu St. , West of Beihai Road , Hanting Dist, Weifang (2026)

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4C Tower, North Side Of Minzhu St. , West Of Beihai Road , Hanting Dist

05/02/2026

What is the impact of adjusting the excitation frequency on the electromagnetic flowmeter?
The excitation frequency in electromagnetic flow meters usually refers to the frequency of the alternating magnetic field, that is, the excitation Hertz number. This frequency has a certain impact on the performance and measurement results of the electromagnetic flowmeter.
1. Sensitivity: The choice of excitation frequency can affect the sensitivity of the electromagnetic flowmeter. Appropriate excitation frequency can improve the response speed of the sensor and the accuracy of measurement.
2. Anti-interference: Various interference sources may exist in different industrial environments, such as electromagnetic interference. By adjusting the excitation frequency, you can choose to better resist external interference under specific environmental conditions and improve the instrument's immunity to interference.
3. Adaptability: Different liquid media may have different responses to excitation frequency. By adjusting the excitation frequency, the adaptability of the electromagnetic flowmeter in different media can be improved.
4. Energy consumption: The choice of excitation frequency may also affect the energy consumption of the electromagnetic flowmeter. In general, higher frequencies may result in higher energy consumption, so there is a trade-off between balancing accuracy and energy consumption.
It is important to note that the excitation frequency should be adjusted according to the specific flow meter model and the technical specifications provided by the manufacturer to ensure optimal performance in the specific application.

02/02/2026

Why should an electromagnetic flow meter be grounded?
In our last article, we clearly explained several contraindications for using electromagnetic flow meters. One of these contraindications is to avoid interference from external electric potentials. Grounding helps to minimize electrical interference between electromagnetic flow meters and other electrical equipment. In industrial environments, where there is a multitude of equipment, the stability of the electromagnetic flowmeter's circuitry needs to be somewhat protected. In order to make the flowmeter has a good working ground, that is, the flow through the electromagnetic flowmeter (sensor) within the fluid is reliably grounded, so that the fluid potential and ground potential is the same, the realization of the sensor's reference potential, the converter / amplifier of the reference potential and the measured fluid potential is the same. Work grounding should adhere to a single point of grounding, can not use the public grounding wire ground. The grounding point should be as far away as possible from the electrical ground, lightning ground and other equipment protective grounding. The distance between the grounding device and the sensor is as short as possible.
Sensor grounding measures generally have the following three kinds:.
The first is the sensor is installed in the metal pipe, and metal pipe wall without insulation, then the grounding conductor can be connected to two pipe fl**ge, through the metal pipe and fluid to maintain a reliable grounding. If the interference is too strong, so that grounding is not enough to counteract interference, then the grounding conductor should be connected from the two pipe fl**ges respectively along the metal piping to the outward extension of the interference can be eliminated.
The second is the sensor installed in plastic pipes or insulated (paint, paint, lining) on the pipe, the sensor should be equipped with a grounding ring on both sides, so that it is in contact with the fluid and will be connected to the two ground rings and sensor fl**ge and then ground; the third is the sensor is installed in the cathode, so the grounding conductor should be extended from the two pipe fl**ges outward along the metal pipe to be able to eliminate interference.
The third is the sensor installed in the cathodic protection pipeline, with galvanic corrosion protection of the pipeline is usually insulated inside and outside so that the fluid is not conductive to ground. In this case, the sensor must use the grounding ring. Grounding ring to be mounted on both ends of the sensor and the connecting pipe fl**ge insulation. The two connecting pipe fl**ges are connected with a copper wire around the sensor to isolate the cathodic protection potential from the sensor.
In addition, sensors, converters and secondary instruments between the circuit grounding and shielding grounding should also be given sufficient attention.
Electromagnetic flowmeter should be installed as far away as possible from the motor, transformer or other power sources that can easily cause induction interference. In the actual production of what countermeasures should be taken, can be distinguished in the following simple way: so that the sensor conduit is filled with static liquid, not connected to the power supply, if there is no excitation current in the electrode can be measured on the signal, then it is from the pipeline system from the external interference or grounding is not good; electromagnetic flowmeter on the power supply, if there is an excitation current in the pipeline and the liquid flow of the electrodes on the signal, it may be the instrumentation Zero point itself is not adjusted.

29/01/2026

You need to know the use of electromagnetic flow meter taboos
Electromagnetic flowmeter working principle is based on Faraday's law of electromagnetic induction, when the conductive fluid flows through the electromagnetic flowmeter magnetic field when the cutting of magnetic lines of force, in the direction perpendicular to the direction of flow of the medium will produce and the average flow rate is proportional to the induced electromotive force. By a pair of electrodes on the wall of the flow meter to detect the induced electromotive force, through the operation can be obtained from the fluid flow. It is this principle determines the use of electromagnetic flowmeter contraindications, but also for us to deal with the protection of the work provides a theoretical basis.
1. Avoid empty pipe measurement
That is, the liquid must be full of pipeline, also does not allow the liquid memory bubbles. If the liquid does not fill the pipe, one of the consequences is that the cross-section of the fluid will be inconsistent with the cross-section of the pipe, resulting in the calculation of volume flow rate deviation; the second is not conductive gas phase layer (or bubbles) blocked the conductor connection between the two electrodes, Faraday's law is not satisfied, can not be induced and the flow rate is proportional to the electromotive force, which will also result in inaccurate measurements. For the insertion of electromagnetic flowmeter, due to the sensor probe (electrode) is located in the center of the pipe, the consequences of empty pipe measurement is particularly obvious.
2. Avoid rapid changes in the liquid
Refers to the conductivity of the liquid must not be a sharp change. Electromagnetic flowmeter for a wide range of applications, such as acids, alkalis, salts, sludge, slurries, etc., different conductivity, but as long as the conductivity in the threshold (10-4 ~ 10-8S/cm, depending on the design of the flowmeter) or more, which determines a certain kind of medium, the conductivity is unchanged. Based on Faraday's law of electromagnetic induction, if the fluid conductivity is changing rapidly, it is equivalent to the internal resistance of the generator changes rapidly, then the potential generated not only with the fluid flow rate, but also with the conductivity, which will enable the detection of the potential and the flow rate is not a single-valued function.
3. Avoid the interference of external electric potential
That is, to avoid the form of external potential and its own interference. Intelligent electromagnetic flowmeter since it is according to the law of electromagnetic induction to work, and its flow signal is very small, only a few millivolts in the full scale, and in the lower limit of the flow, only dozens of microvolts, and therefore very susceptible to the surrounding such as electric motors, transformers, and some electrical equipment and other electromagnetic induction and static electricity generated by the interference. Electromagnetic flowmeter interference introduced by the main in-phase interference and quadrature interference. Its sources are: A.
A. around the operation of electrical equipment in the metal pipeline to produce stray current (such as welding operations on the pipeline, etc.), these currents through the pipeline as well as the pipeline fluid affects the electromagnetic flowmeter; B. electromagnetic flowmeter with the transformer and some electrical equipment to produce electromagnetic induction and electrostatic interference.
B. Electromagnetic flowmeter and motor, electrical equipment, public grounding or connected to the upper and lower water pipes, so that the leakage current of electrical equipment through the public ground into the electromagnetic flowmeter;
C. The electromagnetic field of the surrounding electrical equipment on the signal transmission line and electronic circuit interference.
D. For the delivery of corrosive media or insulated pipeline insulation lining pipeline, due to the flow of fluid in the insulated pipeline and pipe wall friction will produce static electricity, which is transmitted through the liquid to the electromagnetic flowmeter measurement electrode and then transmitted to the measurement line, interfering with the flow signal; E. The electromagnetic flowmeter by the power equipment leakage current through the common ground into the signal transmission line and electronic circuit interference.
E. By the electromagnetic flowmeter itself "transformer effect" generated by the orthogonal interference.
4. Avoid pipeline walls do not allow scaling or sludge deposits
Scale and sludge layer in addition to small changes in the pipeline circulation cross-section, its main effect is to change the resistance between the two electrodes. If the deposit layer resistance coefficient w and the measured fluid resistance coefficient r is the same, then the measurement is not a big problem. If w>r, then the flow signal is large. The very high resistance coefficient of the sedimentary layer is insulating, so that the electrodes are insulated from each other and no flow signal is sent. If w

27/01/2026

How to clean the electromagnetic flowmeter if it is fouled
After long-term use, the electromagnetic flowmeter will become dirty and cause the electrode to scale. This will not only reduce the measurement accuracy but also damage the instrument. Therefore, if the electrode is found to be dirty, we must clean it in time to ensure the accuracy of the measurement.
Methods for cleaning electrodes generally include the following:
1. Mechanical scraper
In this system, each electrode is equipped with a rotating scraper, and the blade of the scraper is perpendicular to the electrode surface. The scraper shaft is driven by an external motor or manually via a hydraulic seal. Can run continuously or intermittently. The scraper shaft is driven by an external motor or manually via a hydraulic seal. Can run continuously or intermittently. This method is generally rarely used in modern electromagnetic flowmeters.
2. Detachable electrode
Removable electrodes use mechanical valves and seals so the electrode can be removed (usually under pipeline operating pressure) for external inspection and cleaning.
3. Electrolysis or "burning" method
This method is to connect the voltage of the power supply between the two electrodes (the secondary device is automatically disconnected during this operation), causing electrolysis to occur on the surfaces of the two electrodes, rapidly releasing gas, and leading to the removal of precipitates. This method is generally used for oily, oily and sludge-type coverings. The heating of the electrodes can also remove fat and oil deposited from sewage.
4. Ultrasonic cleaning
High-energy ultrasound waves are induced on each electrode axis using an external oscillator and transducer. By selecting the length of the motor shaft and the frequency of the ultrasonic wave, antinodes are generated on the electrode surface, thereby forming local cavitation on the electrode to remove deposits. This method is generally used for cleaning crystalline coatings.
Aobo Instrument has specialized in producing electromagnetic flowmeters for many years. If you encounter any problems during the selection, installation, use and maintenance of electromagnetic flowmeters, you can leave a message in the comment area at any time and we will help you answer it.

22/01/2026

How to correctly choose the lining of ABDT-LD electromagnetic flowmeter to extend its service life?
To ensure long-term stable operation of the ABDT-LLD electromagnetic flowmeter under various process conditions, the liner material should be selected based on the corrosiveness, abrasiveness, and operating temperature of the measured medium.
Below are the characteristics and typical applications of commonly used liner materials.

1. Neoprene (CR)

Characteristics

A. Moderate abrasion resistance

B. Resistant to weak acids, weak alkalis, and salt solutions (such as diluted inorganic acids and alkaline solutions)

C. Not suitable for strongly oxidizing media or organic solvents

Maximum Operating Temperature：≤ 60 °C

Typical Applications：Tap water，Industrial water，Seawater and other low-corrosive water media

2. Polyurethane Rubber (UR)

Characteristics

A. Excellent abrasion resistance and tear strength

B. Poor resistance to acids and alkalis

C. Specifically designed for high-abrasion, low-corrosion applications

Maximum Operating Temperature：≤ 65 °C

Typical Applications:Paper pulp,Mineral slurry (such as slag or sand slurry),Abrasive slurries containing solid particles

3. Polytetrafluoroethylene (PTFE / F4)

Characteristics

A. Resistant to almost all strong acids, strong alkalis, organic solvents, and oxidizing agents (including aqua regia, concentrated sulfuric acid, and concentrated hydrochloric acid)

B. Excellent chemical stability; not suitable for molten alkali metals or elemental fluorine at high temperatures

C. Non-melt-processable with relatively low mechanical strength

Maximum Operating Temperature:≤ 160 °C (recommended ≤ 80 °C for continuous operation)

Typical Applications:Highly corrosive acids and alkalis,High-purity chemical solutions,Salt solutions

4. Fluorinated Ethylene Propylene (FEP / F46)

Characteristics

A. Chemical resistance comparable to PTFE

B. Melt-processable with better mechanical strength than PTFE

C. Good transparency, allowing visual inspection of the flow path

Maximum Operating Temperature:≤ 110 °C

Typical Applications:Corrosive acid solutions (such as phosphoric acid and acetic acid),Alkali and,salt solutions,Applications requiring visual flow observation

5. Perfluoroalkoxy (PFA)

Characteristics

A. Chemical resistance equivalent to PTFE

B. Excellent mechanical strength, flexibility, and resistance to cold flow

C. Melt-processable and maintains strong physical properties at elevated temperatures

Maximum Operating Temperature:≤ 180 °C

Typical Applications:Strongly corrosive acids and alkalis,High-purity chemicals (such as semiconductor-grade reagents),High-temperature corrosive process fluidsPoor resistance to acids and alkalis,Specifically designed for high-abrasion, low-corrosion applications

21/01/2026

ABDT-LD Electromagnetic Flowmeter – Electrode Material Selection Guide
The electrodes of an electromagnetic flowmeter are in direct contact with the process fluid. Selecting the appropriate electrode material is critical to ensuring measurement reliability, long service life, and operational safety. The choice must be based on the fluid’s chemical composition, concentration, temperature, conductivity, and presence of abrasive particles.
Selection Recommendations
Prioritize chemical compatibility: Always consult chemical resistance charts or MSDS data for your specific fluid conditions (concentration, temperature, impurities).
Consider abrasion: In slurry or high-solid applications, avoid brittle materials like tantalum. Prefer robust alloys like Hastelloy C-276 or reinforced electrode designs.
Avoid common misconceptions:·
Tantalum ≠ universal acid resistance (fails in alkalis and fluorides)
Titanium ≠ universal chloride resistance (fails in reducing acids like HCl)
Platinum ≠ resistant to aqua regia (it is highly vulnerable)
For aggressive media (e.g., HF, aqua regia, molten caustics): Consult the manufacturer. Alternative solutions may include non-metallic electrodes (e.g., silicon carbide) or switching to a different flowmeter technology.

15/01/2026

The function of the main components of electromagnetic flowmeter
As we learned earlier, the structure of an electromagnetic flowmeter mainly consists of a magnetic circuit system, measuring conduit, electrode, shell, lining, grounding ring, excitation coil and iron core. Next, let us learn the functions of each component
1.Magnetic Circuit System: The role is to generate a uniform direct or alternating magnetic field, typically using an alternating magnetic field. This field is related to the fluid movement and is used to measure the flow velocity through induced electromotive force.
2.Measurement Conduit: Allows the tested conductive liquid to pass through. The measurement conduit must be made of materials that are non-magnetic, have low magnetic permeability, low thermal conductivity, and possess mechanical strength. Materials such as non-magnetic stainless steel, fiberglass-reinforced plastic, high-strength plastic, and aluminum are commonly used.
3.Electrodes: Installed on the measurement tube wall to extract electrode voltage. Electrode materials must withstand fluid wear and corrosion.
4.Casing: Protects the internal components of the electromagnetic flowmeter sensor (excitation coil, core, and electrode wires) from mechanical damage and shields them from adverse environmental effects. The casing must have sufficient mechanical strength, prevent the ingress of water, dust, etc., and exhibit corrosion resistance.
5.Liner: Located inside the measurement tube, it is an insulating material preventing short circuits of the induced electromotive force. The material must resist wear and corrosion, subject to limitations based on fluid temperature.
6.Grounding Ring: Maintains the same electrical potential between the electromagnetic flowmeter sensor and the measured liquid, also providing protection for the fl**ge end face liner. The material must withstand fluid wear and corrosion.
7.Excitation Coil and Core: These components form a magnetic flux density proportional to the excitation current within the measurement tube, inducing electromotive force in the process.

14/01/2026

How an Electromagnetic Flowmeter Works | Faraday’s Law Explained

13/01/2026

How an Electromagnetic Flowmeter Works — Based on Faraday’s Law of Electromagnetic Induction
At the heart of an electromagnetic flowmeter is the sensor, which contains excitation coils and measuring electrodes.
When current is applied to the coils, a stable magnetic field is generated inside the measuring tube.
As a conductive liquid flows through this magnetic field, the charged particles in the fluid are forced to move, creating an induced voltage across the pipe.
This induced voltage is directly proportional to the flow velocity of the liquid.
The electrodes mounted on the pipe wall detect the signal, which is then amplified and processed by the transmitter to calculate the volumetric flow rate.
This measurement principle is based on Faraday’s law of electromagnetic induction.
Because there are no moving parts or flow obstructions, the measurement remains stable, repeatable, and highly reliable — even under demanding process conditions.

08/01/2026

How Electromagnetic Flowmeters Achieve High Accuracy
Based on Faraday’s law of electromagnetic induction, electromagnetic flowmeters offer stable and accurate performance, even under complex operating conditions. Their ability to measure a wide variety of media with precision is mainly due to the following features:
1. No flow obstruction inside the measuring tube
With no throttling or moving parts in the pipeline, pressure loss is minimal, and the requirement for upstream and downstream straight pipe runs is relatively low, making installation more flexible.
2. Stable signal conversion and high reliability
The transmitter operates with stable signal processing and low power consumption, ensuring reliable long-term performance.
3. Comprehensive alarm and self-diagnostic functions
Functions such as empty pipe detection, excitation fault alarms, and high/low flow alarms help identify abnormal operating conditions and improve system safety.
4. Advanced electronic design for long service life
Built with SMD components and surface-mount technology (SMT), the circuitry offers high reliability, strong vibration resistance, and extended service life.
5. Wide measuring range and strong adaptability
Various liner and electrode materials can be selected to match different process media, covering applications from corrosive liquids to abrasive slurries.
6. Suitable for hazardous and explosive environments
Explosion-proof designs are available, ensuring safe and reliable operation in potentially hazardous areas.
7. High immunity to interference with excellent accuracy
Strong resistance to electromagnetic interference allows precise and stable flow measurement across a wide range of conductive liquids

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