How Should I Select A Wastewater Electromagnetic Flow Meter?

Wastewater Electromagnetic Flow Meter are one of the commonly used instruments in wastewater treatment. According to the working principle, there are many types of electromagnetic flow meters, you need to choose the right electromagnetic flow meter according to the actual working situation.

 Understand the Application

• Type of Wastewater: Determine if the wastewater is domestic, industrial, or mixed. The composition (e.g., presence of solids, chemicals, or abrasives) can affect the meter's performance.

• Flow Rate Range: Identify the minimum and maximum flow rates to ensure the meter can handle the expected range.

• Pipe Size: Measure the diameter of the pipe where the meter will be installed.

Meter Specifications

• Accuracy: Look for a meter with an accuracy level suitable for your application. Typically, electromagnetic flow meters offer accuracy within ±0.5% to ±0.2% of the measured value.

• Material: Ensure the meter’s wetted parts (liner and electrodes) are compatible with the wastewater. Common materials include stainless steel, PTFE, and rubber.

• Liner Material: Choose a liner material that can withstand the chemical composition and temperature of the wastewater.

• Electrode Material: Select electrodes that are resistant to corrosion and fouling.

• Installation Requirements

• Flow Profile: Ensure the installation location allows for a fully developed flow profile. Typically, this requires straight pipe runs upstream and downstream of the meter.

• Orientation: Consider the orientation (horizontal, vertical, or inclined) and ensure it aligns with the manufacturer’s recommendations.

• Grounding: Proper grounding is crucial for accurate measurements. Ensure the installation site allows for effective grounding.

• Reason 1

Electromagnetic flow meters can be used on different pipe diameters from small DN(6mm) to quite large DN(3000mm).

• Reason 2

Temperature and pressure selection: Wastewater electromagnetic flowmeter can measure the fluid pressure and temperature is a certain limit, selection, the use of pressure must be lower than the flowmeter specified working pressure. Sewage electro magnetic flowmeter operating temperature depends on the lining material used, generally -20 ℃ ~ 80 ℃, such as special treatment, can exceed the above range, the transmitter allows the measured medium temperature of -40 ~ +160 ℃.

• Reason 3

Electromagnetic flow meter generally consists of 5 parts (flange, liner, electrodes, sensor and transmitter). A wide range of liner and electrode options accommodate various process applications.

• Reason 4

Affordable price. Compared with other flow meters, magnetic flow meter is cost effective so it’s preferably considered by wastewater plants in terms of all the above-mentioned aspects.

• Selection of protection level

The sensors are available in IP67 and IP68 protection classes. If the actual installation location is in a low shaft, the sensors need to be IP68 dustproof submersible type.

• Selection of additional functions

      (1) For the selected basic type, electromagnetic flowmeter with LCD display, 4 ~ 20mA current output and 0 ~ 1KHz frequency output, according to the flowmeter and computer         communication requirements, the need to increase the RS-485 communication port function.

      (2) For the sensor is installed below the ground, should choose the split type.

Example Selection Criteria:

• Flow Range: 0.2 to 12 m/s

• Pipe Size: DN6~DN2200

• Accuracy: ±0.5% of reading

• Liner Material: PTFE (for chemical resistance)

• Electrode Material: Hastelloy (for corrosion resistance)

• Output: 4-20 mA and Modbus RTU

• Installation: Horizontal with 10D upstream and 5D downstream straight pipe runs

By carefully considering these factors, you can select a wastewater electromagnetic flow meter that meets your specific needs and ensures accurate, reliable, and long-lasting performance.