The functional use and scope of application of the plug-in electromagnetic flow meter

The plug-in electromagnetic flow sensor (sensor for short) and electromagnetic flow converter (converter for short) are matched to form a plug-in electromagnetic flowmeter (flowmeter for short) for measuring the volume flow of various conductive liquids in the conveying pipeline.

The sensor has the following characteristics

(1)There are no moving parts in the sensor, which is simple in structure and reliable in operation.

(2)The plug-in structure can be easily installed and disassembled without stopping water under low pressure or under pressure. Therefore, it is very suitable for the fluid measurement of existing pipelines and is convenient for the maintenance and repair of instruments.

(3)The measurement accuracy is not affected by changes in physical parameters such as temperature, pressure, density, viscosity, and conductivity (as long as the conductivity is greater than 5) of the measured medium.

(4)The sensor has almost no pressure loss and very low energy loss.

(5)Compared with the ordinary electromagnetic flowmeter, the manufacturing cost and installation costs are lower and are particularly suitable for flow measurement of large and medium-diameter pipelines.

(6)Adopt advanced low-frequency square wave excitation. Zero stability, strong anti-interference ability, and reliable work.

(7)The flow measurement range is large. The full-scale flow rate in the pipeline under test can be arbitrarily set from 1m / s to 10m / s, and the output signal has a linear relationship with the flow rate.

(8)The flowmeter is not limited to 0～10mA(DC) or 4～20mA (DC) standard current output and 1 ~ 5kHz frequency output at the same time.

Because the flowmeter ( sensor ) has the above-mentioned advantages, it has been widely used in industrial sections such as chemical industry, chemical fiber, metallurgy, chemical fertilizer, paper making, water supply and drainage, sewage treatment, etc., and in automatic control of the production process.

Product form and composition

The product type is magnetic insertion. It is connected to the pipeline through a mounting base, a ball valve, a compression nut, and a positioning screw. A sensor measurement can be divided into two types of structure: measurement tube type and plane electrode type. The measuring tube type sensor is suitable for measuring the cleaning medium; the planar electrode type is suitable for measuring the liquid flow rate containing other impurities in the medium.

Main technical specification

(1)Applicable pipe diameter:
200～2000mm

(2)Flow rate measurement range:

0~1 to 0~10m/s, the full scale is continuously adjustable in the range of 1~10m/s.

(3)Measurement accuracy:

When the full-scale flow rate is 1 m/s, the accuracy is ± 2.5%.

(4)Conductivity of the measured medium:  > 50μS/cm

(5)Working pressure: 1.6Mpa

(6)Electrode material:

Molybdenum-containing stainless steel 0Cr118Ni12Mo2Ti, Hastelloy c-276, titanium Ti, and the like.
(7)Measuring tube (measuring head) material: ABS

(8)The highest temperature of the measured medium: ABS60℃

(9)Shell protection level: It complies with the relevant provisions of IP68 of GB-08-84 standard.

(10)Sensor output signal: 0.209mVp-p/1m/s.

(11)The maximum transmission distance between the sensor and the converter is 50m (please contact the factory for special requirements)

(12)Flowmeter output signal: DC current: 0~10mA, the load resistance is 0~1kΩ

4~20mA, the load resistance is 0~500Ω

Frequency: 1~5KHz, load resistance is 250~1.2kΩ

Structure

The sensor is mainly composed of a measuring head (or measuring tube), an excitation system, an insertion rod, a junction box, a mounting base, and a bee positioning mechanism.

Measuring head (or measuring tube): The measuring head (measuring tube) is located at the particle of the measured flow velocity in the pipeline and is used to detect the flow velocity at this point. The measuring head (or measuring tube) consists of an end or conduit made of insulating material, on which a pair of electrodes are mounted. Except for the electrode tip or the inner wall of the measuring tube, the other parts are insulated from the fluid to be measured.

Excitation system: The excitation system is used to generate a working magnetic field. It consists of an excitation coil and an iron core. It is insulated and sealed into the insertion rod.

Insertion rod: made of stainless steel material. The east measuring tube of the measuring head is fixed in the insertion rod. The excitation lead and the electrode lead are sealed with the medium to be tested by the insertion rod and connected to the junction box. The insertion rod is welded with a direction indicator rod to ensure that the working magnetic field, the flow rate, and the electrode connection line are perpendicular to each other during installation, and meet the requirements of Faraday's law of electromagnetic induction.

Terminal box: The junction box is located on the top of the sensor. The terminals in the junction box act as a connection between the sensor and the converter.

Mounting base: the mounting base is welded to the pipeline under test and is used to connect with the mounting ball valve and insert the electromagnetic flowmeter sensor.

Sealing mechanism: composed of pressing screw seat, pressing nut, rubber washer, and set screw made of stainless steel material. It is used to seal and insert the electromagnetic sensor so that it can withstand a certain working pressure.