1. Types and applicable scope of sewage flow meters

The sewage flow meter consists of two parts: the electromagnetic flow sensor and the electromagnetic flow converter, and is mainly divided into two categories: integrated type and separate type.

The sewage flow meter is a flow meter based on the principle of Faraday's law of electromagnetic induction, which is used to measure the volume flow of conductive liquids and slurries in closed pipes. It is widely used in the flow measurement and control of production processes in industrial and agricultural sectors such as petrochemicals, steel metallurgy, water supply and drainage, water conservancy irrigation, water treatment, environmental sewage, papermaking, medicine, and food.

2. Characteristics of sewage flow meter

1. Strong independence, the measurement is not affected by changes in physical quantities such as liquid density, viscosity, temperature, pressure and conductivity.

2. Simple structure, low failure rate, no moving or obstructive parts in the measuring tube, no blockage and no pressure loss.

3. It has a wide range of applications and a wide measuring range, and is suitable for conductive liquids and liquids containing fibers, solid particles and suspended matter.

4. Low installation requirements and straight pipe section requirements (5D in front and 2D in the back).

5. Stable and reliable operation, using low-frequency square wave excitation, low power consumption and stable zero point.

6. The output signal is diverse and can output linear analog signals, digital signals and alarm signals that are proportional to the flow rate.

3. Selection of sewage flow meter

The selection of instruments is a very important task in instrument applications. According to relevant statistics, 2/3 of the instrument failures in actual applications are caused by incorrect instrument selection and installation. Please pay special attention. Specific precautions are as follows:

1. Name of the fluid being tested and its chemical properties.

2. Maximum flow, minimum flow and common flow. Recommendation: The common flow should be selected within the flow velocity range of 1 to 3 m/s. If it does not meet the requirements, please adjust the caliber specifications of the selected instrument.

3. Maximum operating pressure.

4. Maximum operating temperature and minimum operating temperature.

5. The measured fluid must have a certain conductivity, conductivity ≥ 5µs/cm.

6. The maximum flow and minimum flow must comply with the data in the table.

7. The actual maximum working pressure must be less than the rated working pressure of the flow meter (see sensor nameplate).

8. The maximum and minimum operating temperatures must comply with the temperature requirements of the flow meter (see sensor nameplate).

9. Determine whether negative pressure exists.

10. The selection of electrode and lining materials should meet the chemical properties of the fluid medium.