Aobo Meter, 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.

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.

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.

23/10/2025

Why is temperature and pressure compensation required when measuring steam with a vortex flowmeter?
Vortex flowmeters are widely used in industrial trade settlement and flow measurement due to their simple structure, easy installation, wide measurement range, and low pressure loss. Under varying operating conditions, steam density changes with temperature and pressure. Therefore, during measurement, the temperature and pressure of the measured gas must be incorporated into the flow measurement system. The system then performs conversion calculations for temperature and pressure compensation to achieve accurate measurement.
The significance of temperature and pressure compensation lies in:
Converting the measurement results under actual operating conditions into flow values under standard conditions (standard flow rate). This enables comparability of measurement results across different operating conditions, facilitating statistical analysis and settlement.
In other words, temperature and pressure compensation eliminates measurement errors caused by variations in steam density, thereby achieving higher measurement accuracy.
In practical applications, steam vortex flow meters typically employ one of two methods for temperature and pressure compensation:
1. Separate Compensation: Pressure and temperature sensors are installed separately at the site. Pressure, temperature, and flow signals are input into a flow totalizer (e.g., ABDT-FC6000) for real-time calculation to obtain the standard flow rate.
2. Integrated Compensation: Utilize a temperature-pressure compensated integrated vortex flow meter with built-in temperature and pressure sensors, performing compensation calculations directly within the instrument.
Based on their physical properties, steam can be classified as superheated steam or saturated steam. These differ in density calculation, necessitating careful distinction when selecting compensation methods and parameter settings.
1. For saturated steam, a fixed relationship exists between temperature and pressure. Measuring either parameter allows density to be determined via tables or formulas; thus, single-parameter compensation (temperature or pressure) may meet accuracy requirements in certain scenarios.
2. For superheated steam, the relationship between temperature and pressure is not fixed. Therefore, both temperature and pressure must be measured simultaneously to accurately calculate its density and perform compensation, thereby obtaining the true mass flow rate or standard flow rate.
Additionally, vortex flow meters are not only used for steam measurement but are also commonly employed for gases and certain liquids. In these medium measurements, the necessity for temperature-pressure compensation depends on the compressibility of the medium and the degree of operating condition variation:
1. For gas measurement: Simultaneous temperature and pressure compensation is typically required. Gas volumetric flow is significantly affected by temperature and pressure variations, necessitating settlement based on volumetric flow at standard conditions.
2. For liquid measurement: Temperature compensation alone is generally sufficient, and pressure compensation can often be neglected at pressures below 5 MPa. However, for certain hydrocarbons (such as compressible liquids like crude oil), dual temperature-pressure compensation is still recommended to enhance measurement accuracy.

20/10/2025

How to Choose the Right Steam Pipe Size?
Pick the Wrong One, and It’ll Cost You Big Time!
In steam system design and retrofitting, pipe sizing may seem straightforward — but it’s one of the most critical factors affecting system performance and stability.
Many common issues in steam systems — such as pressure fluctuations, poor heat efficiency, and water hammer — often trace back to one simple cause: improper pipe sizing.
1. The Impact of Incorrect Pipe Sizing
Sizing errors typically fall into two categories:
pipes that are too large, or too small.
1. Oversized Pipes
Higher Initial Investment: Larger pipes mean higher costs for fittings, valves, fl**ges, and insulation.
Higher Installation Costs: Bigger pipes require stronger supports and more complex installation, which drives up labor and material costs.
Greater Heat Loss: A larger surface area means more heat loss. This leads to higher energy waste, more condensate generation, and lower steam dryness and efficiency.
Increased Water Hammer Risk: In oversized pipes, steam velocity is lower, allowing condensate to pool. When high-pressure steam pushes through, it can cause powerful water hammer, damaging valves, joints, and equipment.
Engineering Reference:
Installing DN80 steam piping typically costs about 44% more than DN50.
At 8 kg/cm² steam pressure and 30 °C ambient temperature, a DN150 pipe loses about 85.7% more heat than a DN100 pipe.
2. Undersized Pipes
Excessive Steam Velocity: Too small a pipe dramatically increases flow velocity, resulting in high pressure drops. By the time steam reaches the point of use, pressure and performance drop significantly.
Insufficient Steam Supply: Severe pressure loss limits flow capacity, leaving downstream equipment starved of steam.
Erosion and Vibration: High-velocity steam can erode pipe walls and valves, leading to vibration and noise.
Frequent Water Hammer: Fast-moving steam tends to drag condensate along, causing violent impacts that can damage the entire system.
As you can see, both oversized and undersized pipes come with serious downsides.
So how can you determine the right pipe size for your steam system?
We’ll show you a practical and proven way to do it right.

17/10/2025

Get to Know AOBO Electromagnetic Flow Meters
Precise. Stable. Reliable. — AOBO flow meters deliver accurate fluid measurement for industries worldwide.
With full OEM customization, multiple body materials, and a wide range of sizes, we’ve got every application covered.
Watch the video to discover our core technology in just 30 seconds.

16/10/2025

Selection of Vortex Flowmeter Structures
1. Overview
In steam flow measurement, differential pressure (DP) flowmeters and vortex flowmeters are the two main types in use today. However, when it comes to vortex flowmeters, choosing between inline (full-bore) and insertion-type designs has long been a common dilemma in engineering applications.
The core issue lies in finding a balance between the vortex principle’s dependence on high Reynolds numbers and the practical considerations of cost and installation economics. So, how should one make the right choice?
2. Principle Analysis
A vortex flowmeter is based on the Kármán vortex street principle, where the vortex shedding frequency is linearly proportional to the fluid’s average velocity:
f=st*v/d
where St is the Strouhal number, v is the average flow velocity, and d is the characteristic width of the bluff body.
The discovery of the vortex phenomenon by Strouhal and the concept of the Reynolds number by Reynolds together laid the foundation for modern vortex flowmeters.
However, the principle comes with a limitation: linearity between the vortex frequency and flow rate only holds when the Reynolds number is above 40,000 (Re ≥ 4×10⁴). At larger pipe diameters, the vortex shedding coefficient decreases, and in some cases, vortex shedding may even be lost entirely.
3. Evolution of Structural Designs
Early vortex flowmeters were typically used in pipe sizes ranging from DN50 to DN300. As industrial applications expanded, the demand for large-diameter measurement of steam, compressed air, and process gases grew rapidly.
To overcome the limitations of the vortex coefficient in large diameters, the insertion-type vortex flowmeter was developed.
Although the insertion type provides lower accuracy, it is adequate for most process monitoring applications, while its cost is only about one-third to one-half that of a full-bore design of the same size.
Meanwhile, advances in mechanical machining and electronic detection technology have significantly reduced the difficulty of manufacturing small-diameter full-bore vortex meters, greatly improving signal accuracy. As a result, the applicable range of full-bore vortex flowmeters has expanded to DN8–DN500, while insertion-type designs remain the practical choice for pipe sizes above DN500.
4.Design Considerations for Large-Diameter Applications
It is well known that the meter coefficient (K) of a vortex flowmeter decreases sharply with increasing pipe diameter—approximately proportional to the cube of the diameter (K ∝ D⁻³).
This causes a significant drop in resolution. To mitigate this effect, insertion-type vortex flowmeters were introduced for large-diameter applications, though at the expense of some measurement accuracy.
This raises a question: if insertion types are available, why not use them across all diameters?
First, full-bore vortex flowmeters offer higher measurement accuracy, better repeatability, and superior long-term stability. Their results are more consistent and reliable over time.
Second, from a fluid dynamics standpoint, the pipe frictional resistance can be expressed as:
f=(0.0791*Qn)/(D^5.206 *Sn)
According to the Darcy–Weisbach equation, when the flow coefficient n remains constant, a smaller pipe diameter D leads to higher wall friction, resulting in greater velocity gradients across the cross-section.
Moreover, small-diameter flows naturally exhibit lower Reynolds numbers. Inserting a probe into such a flow further disturbs the velocity field, reducing the Reynolds number even more and deteriorating the vortex shedding behavior. In these conditions, a single-point velocity measurement cannot accurately represent the average flow velocity of the entire cross-section, introducing additional errors.
Finally, when a full-bore structure can be used, it not only ensures accuracy but also provides stable and repeatable measurements. Switching to an insertion-type design in these cases would reduce accuracy and increase installation complexity—offering little benefit in return.
5. Conclusion
Considering both technical performance and economic factors, the selection of vortex flowmeter structures can be summarized as follows:
DN8–DN500: Full-bore (inline) type is recommended. It offers high accuracy, excellent long-term stability, and is ideal for applications requiring high precision or trade measurement.
DN500 and above: Insertion type is recommended. When installed under proper flow conditions, it provides a cost-effective and efficient solution for steam flow monitoring.
For applications requiring high precision or those exposed to strong vibration, consider wide-range or anti-vibration vortex flowmeters to balance accuracy and practicality.

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