Measure Liquid Flow Ease High Accuracy Electromagnetic Flow Meter

Introduction of electromagnetic flowmeter

Electromagnetic flowmeter is a flow measurement instrument based on Faraday's electromagnetic induction principle, which is widely used in flow measurement of liquid and conductive fluids. Its working principle can be briefly summarized as the following steps:

1. Faraday electromagnetic induction principle
The working principle of electromagnetic flowmeter is based on Faraday's law of electromagnetic induction, which describes that when a conductive fluid flows through a magnetic field, an electromotive force (i.e., voltage) is generated in the fluid. The magnitude of this electromotive force is proportional to the flow rate.

Specifically, when the fluid passes through the magnetic field located in the flowmeter pipeline, the charged particles in the fluid (such as ions in water) will move under the action of the magnetic field and generate an electromotive force (voltage) in a direction perpendicular to the magnetic field and the flow rate. This electromotive force is proportional to the flow rate of the fluid.

2. Structural composition
The electromagnetic flowmeter is mainly composed of the following parts:

- **Sensor**: It includes a measuring tube and a magnet. The fluid passing through the measuring tube generates an electromotive force by interacting with the magnetic field.

- **Electrode**: The electrode picks up the electromotive force signal by contacting the fluid. Usually, the electrode is installed on the inner wall of the measuring tube, perpendicular to the direction of fluid flow.
- **Signal converter**: Convert the electromotive force signal received by the electrode into a flow signal, and display and process it.

3. Flow measurement process
- **Magnetic field effect**: When the fluid passes through the measuring tube of the electromagnetic flowmeter, the built-in magnet generates a magnetic field perpendicular to the flow direction.
- **Electromotive force generation**: When charged particles (such as ions) in the fluid move in the magnetic field, an electromotive force is induced in the fluid according to Faraday's law. The magnitude of the electromotive force is proportional to the flow rate.
- **Signal acquisition**: The electromotive force of the fluid in the magnetic field is captured by the electrode, and the voltage difference between the electrode and the fluid reflects the flow rate.
- **Signal processing and flow calculation**: By processing the electromotive force signal, the converter can calculate the actual flow value of the fluid.

4. Advantages and applications
- **No mechanical parts**: The electromagnetic flowmeter has no mechanical parts, so there is no wear and tear, and the maintenance cost is low.
- **Applicable to conductive fluids**: The electromagnetic flowmeter is suitable for flow measurement of various conductive fluids, such as water, sewage, acid and alkali solutions, slurry, etc.
- **Not affected by factors such as fluid density, viscosity, temperature, etc.**: The measurement results are independent of the physical properties of the fluid and have high accuracy.

5. Application scenarios
- Water treatment, chemical processes, food and beverages, medicine, slurry, oil and gas, etc., especially when measuring corrosive or viscous fluids.

It should be noted that electromagnetic flowmeters cannot be used for non-conductive fluids (such as gas, oil fluids) or liquids without charged particles in the fluid.

Pulse Output
Two types of pulse output are available to choose from: frequency output mode and pulse output mode. The meter outputs continuous square wave pulse under frequency mode, while pulse series under pulse mode. Frequency output is usually used for flow rate measurement and short period of time totalization. Pulse output can be connected to an external counter directly and is often used for long period of time totalization.
As mentioned hereinbefore, transistor open collector circuit is used for frequency and pulse output. Therefore, the external DC power supply and load are necessary.

Features
1. Measurement is not affected by the variation of flow density, viscosity, temperature, pressure and conductivity. High accuracy measurement is guaranteed according to the linear measurement principle.
2. No obstacle in the pipe, no pressure-loss and lower requirement for straight pipeline.
3. DN 6 to DN2000 covers a wide range of pipe size. A variety of liners and electrodes are available to satisfy different flow characteristic.
4. Programmable low frequency square wave field excitation, improving measurement stability and reducing power consumption.
5. Implementing 16 bits MCU, providing high integration and accuracy; Full-digital processing, high noise resistance and reliable measurement; Flow measurement range up to 1500:1.
6. High definition LCD display with backlight.
7. RS485 or RS232 interface supports digital communication.
8. Intelligent empty pipe detection and electrodes resistance measurement diagnosing empty pipe and electrodes contamination accurately.
9. SMD component and surface mount technology (SMT) are implemented to improve the reliability.

Main Applications

TQMF electromagnetic flowmeter can be used to measure the volume flow of conductive fluid in a closed pipeline. It is widely applied in the flow measurement and control in the fields of chemical and petroleum industry, metallurgy industry, water and waste water, agriculture and irrigation, paper making, food and beverage industry and pharmaceutical industry. 1.3Ambient Conditions Ambient temperature: sensor: -25℃ to + 60℃; converter: -25℃ to + 60℃. Relative humidity: 5% to 90%; 1.4Working Conditions Maximum fluid temperature: Compact type: 60℃ Remote type: Teflon 150℃ Neoprene 80℃; 120℃ Polyurethane 70℃ Fluid conductivity: ≥ 5S/cm

Measuring Principles

The measuring principle of electromagnetic flowmeter is based on the electromagnetic induction law of Farady. The sensor is mainly composed of measuring tube with isolate lining, a pair of electrodes installed by penetration of the measuring tube wall, a pair of coils and iron core to produce working magnetic field. When the conductive fluid flows through the measuring tube of the sensor, the voltage signal in direct proportion to the average flow velocity of the fluid will be inducted on the electrodes. The signal is amplified and treated by the transmitter to realize various display functions.

Converter Circuit Schematic

The converters supplies a stable exciting current to the coil in the sensor of electronetic flowmeters to get B constant and amplifies the electromotive force and convert it into standard signals of current or frequency so that the signals can be used for displaying, controlling and processing. The schematic of converter circuit is shown in Fig. 2.1.

Table of Parameter Setting Menu

The converter setting menu consists of 45 items. Many of them are set up by manufacturer before shipping. It is not necessary to change them when applying. There are only a few of them to be set by user according to the application. The menu items are listed in the table below:

Scenario application:

FAQ
1. Q: What information need to be provided to choose the suitable model?
A: Application field, Nominal pressure ,Medium & medium temperture , Power supply , Output,
Flow range, Accuracy, Connection and other parameters.
2. Q: Are you a trade company or a manufacturer?
A: We are an ISO approved manufacturer specialized in level and flow measuring instruments.
OEM & ODM service are available. Welcome to visit us in China.
3. Q: What is your MOQ?
A: To start our cooperation, sample order is acceptable.
4. Q: What is your delivery date for the Intelligent Mini Micro Turbine Fuel Oil Diesel Flow Meter?
A: The delivery date is about 3-15 working days after receipt of payment.
5. Q: What is your payment terms?
A: We support T/T, PayPal ,Western Union.
For mass production order, it is 30% deposit in advance and 70% balance before shipment.
6. Q: Do you have a warranty for the Flow Meter?
A: Yes, we have the warranty of 12 months.