Flow Meters

Electromagnetic flowmeter working principle

Electromagnetic flow meter is a velocity flow measurement device which measures volume flow of conductive liquids. It not only has on site display, but also can output standard current signals for recording, adjustment and control, to realize automatic detection and long-distance signal transmission. It can measure the flow of liquids, pastes, and slurries in water, wastewater, chemical, fertilizer, dairy, food, beverage, pharmaceutical, medical, petrochemical, iron, steel, paper, mining, and agricultural industries etc. The structure of the instrument has integral type and remote type.

  • Application: Industrial Flow Measurement.
  • Measuring Range: liquid:0.2-30 m
  • Process Connection: G2 Thread/ M95*2.0
  • Energy Transducer Material: ABS,PVC,PTFE
  • Temperature:-40~ 75 Deg C (LCD:-20ºC~ +70ºC)
  • Temperature compensation: The whole range with automatic compensation
  • Process Pressure :±0.1MPa
  • Precision:0.2% of actual range
  • Signal output:4-20mA, pulse, RS 485 (Option: HART)
  • Power Supply: DC20V~32V ≥30mA

Features of electromagnetic flowmeter

  • There are no moving parts in measuring tube, so it is convenient for maintenance. No flow-blocking parts, so it has quite low-pressure loss.
  • The lowest conductivity of the tested liquid is ≥20μs/cm, with various lining materials, it can be used to measure the flow of various acids, alkalis, salt solutions, slurry, mineral pulp and paper pulp etc.
  • The performance of the instrument is not affected by the properties of the material such as corrosiveness, viscosity, pressure, density, acidity, and alkalinity. The induction voltage signal of sensor has a linear relationship with the average flow rate, which ensure high accuracy.
  • With Low-frequency rectangular wave excitation, it is not affected by the power frequency and various interferences on site, so that to ensure stable and reliable measuring.
  • Not affected by the direction of the fluid, both positive and negative flow can be accurately measured.
  • With LCD backlit display, parameters can be modified on site conveniently. With empty pipe detection/alarm function, the unit can detect if the pipe is full or drained /empty.

Electromagnetic flowmeter installation guidelines

To ensure the stable and reliable performance of the sensor, please pay attention to the following requirements when choosing the installation location:

  • Keep away from equipment with a strong magnetic field as far as possible, such as large motors, large transformers, frequency conversion equipment
  • Please better install in a dry and ventilated place, not a humid
  • Direct sun exposure or direct raining is better to be The environment temperature should be not more than 60 °C and relative humidity not more than 95%.
  • Choose a place where is convenient for operation and
  • To avoid negative pressure, the flow sensor should not be installed at the pump inlet, but at the pump Valves should always be mounted on the downstream side of the flow sensor.

Electromagnetic flowmeter installation requirements

In order to ensure correct measuring, please pay attention to the following requirements when choosing the line position:

  • The flow sensor can be mounted vertically or If the flow sensor is mounted vertically, the flow direction should always be upwards.
  • The medium should always be full-filled in pipe at the installation location to avoid not full filled pipes and gas adhering to the
  • For liquid-solid two-phase flow, it’s better to choose perpendicular installation to make liner of sensor attrition uniform and prolong working
  • When sensor is not fully filled, it can raise end pipeline of flow meter and makes its full
  • Diameter-Varing: When flow rate is too large or too small, we should use this installation method change diameter to meet flow rate Straight pipe upstream ≥10DN, straight pipe downstream ≥5DN(DN means pipe diameter)
  • The front and rear straight pipes are ≥10DN at the front of the flowmeter and ≥5DN at the back.

Electromagnetic flowmeter wiring

  • The remote type signal cable should use a customized dedicated cable, the shorter the cable, the
  • A Yz medium-sized rubber sheathed cable is optional for the excitation cable, and its length is the same as that of the signal
  • Signal cables must be strictly separated from other power sources and cannot be laid in the same
  • The signal cable and excitation cable should be as short as possible, and the excess cables should not be rolled The excess cables should be cut off and the joints should be re-welded.
  • When the cable is connected to the electrical interface of the sensor, insert a U-shape at the port to prevent rainwater from penetrating into the sensor

Electromagnetic flow meter earthing

Electric potential difference is not allowed between measuring sensor and shells or converter protection grounding. Electromagnetic flowmeter must be ground connection separately before using, if grounding together with other instruments or electrical devices, the leakage current in-ground wire may produce series mode interference to the measurement signal, it could cause electromagnetic flowmeter can not work.

  • Measurement sensors must be properly grounded;
  • Earthing wire should not transmit any interference voltage;
  • Grounding wires are not allowed to connect to other electrical equipment at the same time.