Electromagnetic Flowmeter Selection and Installation Rules:
First, the first clear requirements of the measurement needs of this unit should be clear, there are several, mainly: measuring medium, flow m3 / h (minimum, operating point, maximum), medium temperature °C, medium pressure MPa, device mode (pipeline or Spiked) and so on.
Second, the selection of conditions (electromagnetic flowmeter) conditions 1, the measured medium is necessary to be conductive liquid (that is, the fluid required to be measured has the lowest limit of conductivity).
2. The measured medium should not be rich in more ferromagnetic media or many bubbles.
Third, it should be known that the principle of measuring electromagnetic flow meters based on Faraday's law of electromagnetic induction measurement principle, that is, measuring the flow of fluid flow through the magnetic field perpendicular to the direction of activity, conductive fluid activity and induce a uniform flow rate (also known as volume flow Proportional to the voltage, the voltage signal is detected by two electrodes that are in direct contact with the fluid, and is transmitted to the amplifier via a cable, which is then converted into an output signal.
Fourth, we should know the main characteristics of the electromagnetic flow meter:
(1) There is basically no pressure loss in the measuring tube, it is not easy to block, and it has common adaptability to the measurement of the slurry type;
(2) Low demand for straight sections;
(3) Excitation of low-frequency rectangular wave is not affected by the frequency and interference of field distributors, and the operation is stable and secure;
(4) The body of the transmitter can be made of stainless steel, and it has anti-acid, anti-alkali and anti-corrosion abilities after adding fabric materials;
(5) A dedicated smart chip can be used for the on-site appearance converter, and the parameter setting is convenient;
(6) The transmitter can be equipped with a self-calibration system. The transmitter constant and factory calibration value can be self-calibrated at any time for easy commissioning and maintenance.
(7) The measuring range is wide, and the full-scale flow rate can be set within the range of 0.3m/s to 12m/s;
(8) The piercing type can be installed or disassembled under constant flow conditions;
(9) Wide application scale: It can be used in the fields of chemical industry, metallurgy, papermaking, food, petroleum, and urban water supply.
Fifth, the type of selection key 1, the first clear is the choice of pipeline type ') electromagnetic flowmeter '), or piercing electromagnetic flowmeter.
2. Normally, the field-free electromagnetic flowmeter is selected and its output 4-20mA (or 0-10mA) current signal is on the secondary appearance of the control room, and the flow rate and the total amount can be shown.
3. If it is convenient to investigate the flow in the pipeline during the on-site operation, you can select the spot appearance electromagnetic flowmeter.
4. When the demand for environmental requirements or measurement accuracy is high, safe voltage intelligent electromagnetic flowmeters can be selected.
5, in 200mm or more large diameter measuring flow or constant flow state installation and disassembly, you can preferentially choose piercing or enhanced penetration electromagnetic flowmeter.
6. Key selection of sensor diameter 1. The caliber of the selected sensor is the same as that of the connected technical pipe. Its advantage is that the device is convenient (no need for different diameter pipe); the condition is that the flow rate of the fluid in the pipe must be 0.3m/s—10m/ Within the scope of the s scale; its application status is in the early stage of the project and the fluid flow rate in the pipe is in a low state.
2. The caliber of the selected sensor is not the same as that of the connected technical pipe. The applicable conditions are: (1) Low flow rate, stable flow rate: (2) Decreasing cost-effectiveness:
7. The selection of fabric materials is based on the corrosivity, wear and temperature of the tested medium of the company. It is selected by the subscriber and can be referred to the "fabric data function and applicable scale table" supplied by various manufacturers.
8. The selection of electrode data is based on the corrosiveness of the company's measured medium, which is selected by the orderer. Refer to the “Electrode Data Corrosion Resistance Function Table†supplied by various manufacturers.
Nine, protection level selection according to national standard GB4208-84, shell protection grade: If the appearance of the device below the ground and often flooded should be selected submersible type; if the appearance of the device on the surface should be selected to prevent water spray type .
Ten, the upper limit of the flow of the selection 1, usually choose the transmitter's path and the same as the connecting pipe path. Because there is a strict functional relationship between the path, flow rate, and flow rate, the upper limit flow rate table of the electromagnetic flowmeter supplied by the manufacturer can be selected when selecting, and the upper limit flow value can be selected under the corresponding path.
2. When the flow rate in the technical piping is too low to reach the minimum upper flow value in the corresponding path in “1â€, the path diameter of the transmitter smaller than the technical piping can be selected, that is, before and after the transmitter. Reducer.
Eleventh, the selection of the device mode 1, the whole type: The flowmeter's sensing some and transform some in one, strengths are easy to install.
2. Separation: Some sensors of the flowmeter will be installed on the pipeline under test, and some devices will be changed in an easy-to-operate room. It is suitable for occasions with poor on-site environment (but its length should be less than 30m).
12. Selection of Grounding Ring If the pipeline connecting the exterior is related to the insulation of the measured medium, the grounding ring must be selected.
13. Selection conditions of ball valves With regard to technical requirements, the fluid flow in the pipeline must not be stopped, and the demand medium must not overflow, so the ball valve needs to be installed. However, when the flowmeter is allowed to be disconnected (or the assembly and disassembly operation does not affect the pipeline operation), the flowmeter is directly mounted on the flange short pipe without adding a ball valve.
XIV. The device focuses on the key 1. The axis of the electrode must adhere to an approximate level.
2. Ensure that the measuring tube is filled at all times.
3. The installation space for the bolts and nuts to be satisfied in the vicinity of the pipe flange.
4. There must be pipeline support in the pipe section where the flowmeter is installed to reduce the oscillation of the pipeline operation.
5, proximity to the flowmeter should prevent strong electromagnetic fields.
6, long pipelines, should be in the flowmeter device control valve and shut-off valve.
7. In case of "open feed or discharge" condition, it shall be installed in the low section of the pipeline.
8. Based on the axis of the electrode, the inlet straight pipe section should be greater than or equal to 5 times the measuring pipe diameter, and the outlet pipe should be greater than or equal to 2 times the measuring pipe diameter.
15. The grounding requirements of the (flow meter) sensor should have an outstanding ground wire alone (copper section ≥ 16mm2) with a grounding resistance of <10 ohms; if the pipeline connecting the sensor is coated with an insulating layer or a non-metallic pipe, A grounding ring should be provided on both sides of the sensor (grounding conductor copper core section ≥ 16mm2).
XVI. Cable and Electrical Connections Focus on key disconnected cables (signal transmission and excitation). The shorter the view from the reduction of disturbances and savings, the better. It is usually necessary to coordinate the conductivity of the medium, the cross-section of the excitation cable, and the type of signal cable (core, layer, shield).
First, the first clear requirements of the measurement needs of this unit should be clear, there are several, mainly: measuring medium, flow m3 / h (minimum, operating point, maximum), medium temperature °C, medium pressure MPa, device mode (pipeline or Spiked) and so on.
Second, the selection of conditions (electromagnetic flowmeter) conditions 1, the measured medium is necessary to be conductive liquid (that is, the fluid required to be measured has the lowest limit of conductivity).
2. The measured medium should not be rich in more ferromagnetic media or many bubbles.
Third, it should be known that the principle of measuring electromagnetic flow meters based on Faraday's law of electromagnetic induction measurement principle, that is, measuring the flow of fluid flow through the magnetic field perpendicular to the direction of activity, conductive fluid activity and induce a uniform flow rate (also known as volume flow Proportional to the voltage, the voltage signal is detected by two electrodes that are in direct contact with the fluid, and is transmitted to the amplifier via a cable, which is then converted into an output signal.
Fourth, we should know the main characteristics of the electromagnetic flow meter:
(1) There is basically no pressure loss in the measuring tube, it is not easy to block, and it has common adaptability to the measurement of the slurry type;
(2) Low demand for straight sections;
(3) Excitation of low-frequency rectangular wave is not affected by the frequency and interference of field distributors, and the operation is stable and secure;
(4) The body of the transmitter can be made of stainless steel, and it has anti-acid, anti-alkali and anti-corrosion abilities after adding fabric materials;
(5) A dedicated smart chip can be used for the on-site appearance converter, and the parameter setting is convenient;
(6) The transmitter can be equipped with a self-calibration system. The transmitter constant and factory calibration value can be self-calibrated at any time for easy commissioning and maintenance.
(7) The measuring range is wide, and the full-scale flow rate can be set within the range of 0.3m/s to 12m/s;
(8) The piercing type can be installed or disassembled under constant flow conditions;
(9) Wide application scale: It can be used in the fields of chemical industry, metallurgy, papermaking, food, petroleum, and urban water supply.
Fifth, the type of selection key 1, the first clear is the choice of pipeline type ') electromagnetic flowmeter '), or piercing electromagnetic flowmeter.
2. Normally, the field-free electromagnetic flowmeter is selected and its output 4-20mA (or 0-10mA) current signal is on the secondary appearance of the control room, and the flow rate and the total amount can be shown.
3. If it is convenient to investigate the flow in the pipeline during the on-site operation, you can select the spot appearance electromagnetic flowmeter.
4. When the demand for environmental requirements or measurement accuracy is high, safe voltage intelligent electromagnetic flowmeters can be selected.
5, in 200mm or more large diameter measuring flow or constant flow state installation and disassembly, you can preferentially choose piercing or enhanced penetration electromagnetic flowmeter.
6. Key selection of sensor diameter 1. The caliber of the selected sensor is the same as that of the connected technical pipe. Its advantage is that the device is convenient (no need for different diameter pipe); the condition is that the flow rate of the fluid in the pipe must be 0.3m/s—10m/ Within the scope of the s scale; its application status is in the early stage of the project and the fluid flow rate in the pipe is in a low state.
2. The caliber of the selected sensor is not the same as that of the connected technical pipe. The applicable conditions are: (1) Low flow rate, stable flow rate: (2) Decreasing cost-effectiveness:
7. The selection of fabric materials is based on the corrosivity, wear and temperature of the tested medium of the company. It is selected by the subscriber and can be referred to the "fabric data function and applicable scale table" supplied by various manufacturers.
8. The selection of electrode data is based on the corrosiveness of the company's measured medium, which is selected by the orderer. Refer to the “Electrode Data Corrosion Resistance Function Table†supplied by various manufacturers.
Nine, protection level selection according to national standard GB4208-84, shell protection grade: If the appearance of the device below the ground and often flooded should be selected submersible type; if the appearance of the device on the surface should be selected to prevent water spray type .
Ten, the upper limit of the flow of the selection 1, usually choose the transmitter's path and the same as the connecting pipe path. Because there is a strict functional relationship between the path, flow rate, and flow rate, the upper limit flow rate table of the electromagnetic flowmeter supplied by the manufacturer can be selected when selecting, and the upper limit flow value can be selected under the corresponding path.
2. When the flow rate in the technical piping is too low to reach the minimum upper flow value in the corresponding path in “1â€, the path diameter of the transmitter smaller than the technical piping can be selected, that is, before and after the transmitter. Reducer.
Eleventh, the selection of the device mode 1, the whole type: The flowmeter's sensing some and transform some in one, strengths are easy to install.
2. Separation: Some sensors of the flowmeter will be installed on the pipeline under test, and some devices will be changed in an easy-to-operate room. It is suitable for occasions with poor on-site environment (but its length should be less than 30m).
12. Selection of Grounding Ring If the pipeline connecting the exterior is related to the insulation of the measured medium, the grounding ring must be selected.
13. Selection conditions of ball valves With regard to technical requirements, the fluid flow in the pipeline must not be stopped, and the demand medium must not overflow, so the ball valve needs to be installed. However, when the flowmeter is allowed to be disconnected (or the assembly and disassembly operation does not affect the pipeline operation), the flowmeter is directly mounted on the flange short pipe without adding a ball valve.
XIV. The device focuses on the key 1. The axis of the electrode must adhere to an approximate level.
2. Ensure that the measuring tube is filled at all times.
3. The installation space for the bolts and nuts to be satisfied in the vicinity of the pipe flange.
4. There must be pipeline support in the pipe section where the flowmeter is installed to reduce the oscillation of the pipeline operation.
5, proximity to the flowmeter should prevent strong electromagnetic fields.
6, long pipelines, should be in the flowmeter device control valve and shut-off valve.
7. In case of "open feed or discharge" condition, it shall be installed in the low section of the pipeline.
8. Based on the axis of the electrode, the inlet straight pipe section should be greater than or equal to 5 times the measuring pipe diameter, and the outlet pipe should be greater than or equal to 2 times the measuring pipe diameter.
15. The grounding requirements of the (flow meter) sensor should have an outstanding ground wire alone (copper section ≥ 16mm2) with a grounding resistance of <10 ohms; if the pipeline connecting the sensor is coated with an insulating layer or a non-metallic pipe, A grounding ring should be provided on both sides of the sensor (grounding conductor copper core section ≥ 16mm2).
XVI. Cable and Electrical Connections Focus on key disconnected cables (signal transmission and excitation). The shorter the view from the reduction of disturbances and savings, the better. It is usually necessary to coordinate the conductivity of the medium, the cross-section of the excitation cable, and the type of signal cable (core, layer, shield).
Shuttering Magnets,Precast Shuttering Magnets,Formwork Shuttering Magnets,Magnetic Bar Shuttering Magnets
Anfeng Industrial Co.,Ltd , https://www.afmagnets.com