Split electromagnetic flowmeter
The split electromagnetic flowmeter is a kind of i
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Description
I. overview
The split electromagnetic flowmeter is a kind of inductive instrument used for measuring the volume and flow rate of conductive medium in pipes in Jiangsu according to Fala's law of electromagnetic induction. It adopts digital embedded technology to realize digital excitation. At the same time, the CAN fieldbus is used in the electromagnetic flowmeter. It belongs to the domestic level and the technology reaches the domestic level. The electromagnetic flowmeter can also display 4 to 20mA current signals for recording, adjusting and controlling. It has been widely used in chemical technology, environmental protection, metallurgy, medicine, paper making, water supply and drainage, and other industrial technology and management departments. The electromagnetic flowmeter can not only measure the flow rate of the general conductive liquid, but also measure the volume flow of liquid solid two phase flow, high viscosity liquid flow and salt, strong acid and strong alkali liquid.
Two, characteristics
The instrument has simple and reliable structure, no movable parts and long working life.
• no choke block, no pressure loss and fluid blockage.
No mechanical inertia, fast response and good stability, it can be applied to automatic detection, adjustment and program control system.
The accuracy of measurement is not affected by the type of medium and its physical parameters such as temperature, viscosity, density and pressure.
The combination of PTFE or rubber lining and HC, HB, 316L, Ti and other electrode materials can meet the needs of different media.
There are various types of flowmeters, such as pipe type and plug-in type.
Adopt EEPROM memory, measure operation data storage, protect safety and reliability.
There are two forms of integration and separation.
High definition LCD backlight display.
• no choke block, no pressure loss and fluid blockage.
No mechanical inertia, fast response and good stability, it can be applied to automatic detection, adjustment and program control system.
The accuracy of measurement is not affected by the type of medium and its physical parameters such as temperature, viscosity, density and pressure.
The combination of PTFE or rubber lining and HC, HB, 316L, Ti and other electrode materials can meet the needs of different media.
There are various types of flowmeters, such as pipe type and plug-in type.
Adopt EEPROM memory, measure operation data storage, protect safety and reliability.
There are two forms of integration and separation.
High definition LCD backlight display.
Three, technical parameters
| Applicable diameter | DN15mm 2600mm | |
| Electrode materials | 316L (stainless steel), HC (Hastelloy C), HB (Hastelloy B), Ti (TI), Ta (TA) | |
| Applicable medium | Conductivity of >5us/cm liquid | |
| measuring range | 0.1 to 10m/s (extended to 15m/s) | |
| Upper limit of measurement | 0.5 ~ 10m/s, recommended 1 ~ 5m/s | |
| Accuracy grade | 0.3, 0.5, 1 (with caliber). | |
| output signal | 4 ~ 20mADC, load less than 750 ohm; 0 ~ 3KHz, 5V active, variable pulse width, effective frequency output: RS485 interface | |
| Working pressure | 1.0MPa, 1.6MPa, 4.0MPa, 16MPa (special) | |
| Fluid temperature | Reference material for -20 ~ 80 ~ C, 80 ~ 130 C, 130 ~ 180 C | |
| ambient temperature | The sensor is -40 to 80 degrees centigrade and -15 to 50 C. | |
| ambient temperature | Less than 85%RH (20 degrees centigrade) | |
| Cable outlet dimensions | M20 * 1.5 | |
| Power supply | 220VAC + 10%; 50Hz + 1Hz; 24VDC + 10% | |
| Work consumption | Less than 8W | |
| Enclosure protection level | Integrated: IP65 split type: sensor IP68 converter IP6 | |
| Grounding ring material | 1Cr18Ni9Ti (stainless steel), HC (Hastelloy C), Ti (titanium), Ta (TA), Cu (Cu) | |
| Connecting flange | GB GB9119-88 (DIN2051, BS4504) | |
Four, working principle
The principle of the split electromagnetic flowmeter is the instrument automation based on Faraday's law of electromagnetic induction. The measuring tube of the flowmeter is a non permeable alloy short pipe lined with insulating material. Two electrodes pass through the wall along the diameter of the tube and are fixed on the measuring tube. The electrode head is basically flush with the inner surface of the lining. The excitation coil will generate a magnetic field with a magnetic flux density of B in the direction perpendicular to the axis of the measuring tube when it is pulsed by a two way square wave. At this point, if a liquid with a certain conductivity flows through the measuring tube, the cutting force line will induce the EMF E. The electromotive force E is proportional to the magnetic flux density B, and the product of the inner diameter D and the average velocity V is measured. The EMF E (flow signal) is detected by the electrode and sent to the converter through the cable. After amplifying the flow signal, the converter can display fluid flow and output pulses, simulate current and other signals for controlling and adjusting the flow.
E = KBdV
Formula: E -- the signal voltage between electrodes (V).
B -- magnetic flux density (T)
D -- measuring tube inner diameter (m)
V -- mean velocity (m/s)
Type K and D are constants. Because the excitation current is constant current, B is also constant. From E = KBdV, it is known that the volume flow Q is proportional to the E of signal voltage, that is, the signal voltage E of flow induction is linearly related to the volume flow Q. Therefore, as long as the E is measured, the flow rate Q can be determined, which is the basic principle of the electromagnetic flowmeter.
From E = KBdV, we can know that the temperature, density, pressure, conductivity and liquid solid component ratio of liquid solid two phase fluid will not affect the measurement results. As for the flow state, as long as it meets the axisymmetric flow (such as laminar or turbulent flow), it will not affect the measurement results. Therefore, electromagnetic flowmeter is a true volume flowmeter. For manufacturers and users, as long as the calibrated ordinary water can be used to measure the volume of any other conductive fluid medium without any modification, it is a prominent advantage of the electromagnetic flowmeter, which is not available by any other flowmeter. There is almost no pressure loss and high reliability in measuring the inactive and choke components in the tube.
Formula: E -- the signal voltage between electrodes (V).
B -- magnetic flux density (T)
D -- measuring tube inner diameter (m)
V -- mean velocity (m/s)
Type K and D are constants. Because the excitation current is constant current, B is also constant. From E = KBdV, it is known that the volume flow Q is proportional to the E of signal voltage, that is, the signal voltage E of flow induction is linearly related to the volume flow Q. Therefore, as long as the E is measured, the flow rate Q can be determined, which is the basic principle of the electromagnetic flowmeter.
From E = KBdV, we can know that the temperature, density, pressure, conductivity and liquid solid component ratio of liquid solid two phase fluid will not affect the measurement results. As for the flow state, as long as it meets the axisymmetric flow (such as laminar or turbulent flow), it will not affect the measurement results. Therefore, electromagnetic flowmeter is a true volume flowmeter. For manufacturers and users, as long as the calibrated ordinary water can be used to measure the volume of any other conductive fluid medium without any modification, it is a prominent advantage of the electromagnetic flowmeter, which is not available by any other flowmeter. There is almost no pressure loss and high reliability in measuring the inactive and choke components in the tube.
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