# A short yet deep preface to Magnetic flow meter

by Hei White Heiwhite

Flow measurement is critically essential to run industrial plants efficiently. There is a cluster of flow measurement devices to measure the flow rate of various liquids. The magnetic flow meter is one of those devices.

Magnetic flow meter also referred to as Mag meter, a magnetic inductive flow meter is used to measure the volumetric flow rate of chemical solution, paper pulp, sewage slurry, conductive fluid, etc. The magnetic inductive flow meter measures the fluid rate by the voltage induced across the liquid. It requires conductive fluid i.e. water that contains ions and a pipe with an electrically insulating surface.

For complete details refer to  https://www.silverinstruments.com/

## Working principle of magnetic flow meter

Magnetic inductive flow meter or Mag meter comprises two main parts i.e. transmitter and a sensor. The combination of these two parts measures the flow rate. Mag meter sensor is placed in line with the pipes as the fluid flows through the pipe induced voltage generated by the liquid is measured. This induced voltage generated by the sensor is transferred to the transmitter. The transmitter alters the voltage into a flow measurement and transmits it to the control system.

## Measurement principle

The magnetic inductive flow meter measures flow consistent with Faraday's law of electromagnetic induction. Inductive flow meter has an intensive range of measurable rates. The ratio of the utmost flow rate to the minimum flow rate is generally 20: 1. It is suitable for a wide range of industrial pipe diameters. The output signal is linear with the measured flow rate. It can measure fluids with electrical conductivity ≥5μs / cm. The magnetic inductive flow meter is used to measure abrasive fluid, salt solution, water, chemicals, sewage, pulp slurry, etc. But magnetic inductive flow meter cannot measure the flow of gas, steam, oil and pure water.

### Points to be considered before choosing the right magnetic inductive meter for you

• Property of fluid i.e. fluid is conductive or water-based.
• Operating time of pipe.
• The fluid is slurry or abrasive.
• Size of pipe i.e. diameter, length.
• Compatibility of the fluid with the sensor of the magnetic inductive meter.
• Type of display required i.e. integral or remote.
• Type of output required i.e. digital or analog.
• Minimum and maximum flow rate required for the flow meter.
• Minimum and maximum temperature required for the flow meter.
• Minimum and maximum pressure required for the flow meter.

### Technical Specifications

• Power supply: 220VAC, 24VDC, 3.6V battery
• Accuracy: 0.5%,0.25%
• Protection level: IP65, IP67, IP68
• Bidirectional measurement
• Large turndown ratio: 150:1
Electromagnetic flow transmitter output: 4-20mA.
• Integral type of magnetic inductive flow meter.
• Flow transmitters with communication: RS 485, Modbus RTU, Hart protocol, Profibus-DP.
• Inline type flow meter
• insertion type mag sensor.
• Process Connection: flange, tri-clamp, insertion type, threaded magnetic flow meter.
• Remote type magnetic flow transmitter.

### Benefits

• Cost-effective for aggressive chemicals and slurries.
• Digital flow meter to show total flow and instant flow.
• Obstruction-less.
• Different sensor sizes: such as 1 inch, 2 inches, 4 inches, 8 inches, 24 inches.
• Highly accurate volumetric flow measurement.
• It can be used as a chemical flow meter or acid-resistant flow meter.
• Different material options for your various process measurement needs.

## Applications of Magnetic flow meter

Magnetic inductive flow meter has a variety of applications in different types of industries.

• Pharmaceutical industry – in a pharmaceutical industry critical parameters are followed to produce life-saving medicines. To control these parameters flow meters are used to regulate the mixing of chemicals, coloring coating of pills, defining the size of pills, coating of medicine. Turbine flow meter, ultrasonic flowmeter, Coriolis flowmeter are some of the most commonly used flow meters used in the pharmaceutical industry.
• Food and beverages industry - Electromagnetic and mass flow meter is used to regulate the flow of acids and liquids respectively with high accuracy in the food and beverages sector. Coriolis flow meter is used to regulate the flow of gases.
• Oil and gas industry – At petroleum refineries where the raw oil is processed to produce various petroleum products like diesel, petrol, kerosene oil, wax, etc. Critical measurement and analysis of the volumetric flow rate are required to process petroleum and produce petroleum products. Specially designed flow meter helps in regulating the volumetric flow rate during refining process making is safer and easy to operate.
• Sanitary or sewage treatment plants – At sanitary or sewage treatment plants a huge amount of liquid slurry flows through the pipes. The slurry liquid goes passes through various small filtration plants for the treatment. To regulate the volumetric flow rate of this sewage slurry magnetic flow meter is used at different filtration process plants for flow measurement.

There are several other applications where magnetic inductive flow meters are used to measure volumetric flow rate with high precision like chemical and petrochemical industries, pulp and paper industries, industries where a highly corrosive and abrasive fluid is processed, etc.