Electromagnetic Flowmeter Industry Application of Waste Water
Treatment
1. Introduction
The MLF electromagnetic flowmeter works according to Faraday's law
of electromagnetic induction and consists of a sensor and a
converter. Used to measure the conductivity of liquids or solids.
Under normal circumstances, its conductivity should be greater than
5μS/cm (the conductivity of tap water and raw water is about
100-500μS/cm), and it can also be used to measure acids, alkali,
brine, pulp or pulp and other media. But these media cannot contain
a lot of magnetic substances and bubbles.
MLF electromagnetic flowmeter is an instrument for measuring liquid
fluidity. It is widely used in flow measurement in metallurgy,
chemical industry, paper making, environmental protection,
petroleum, textile, food, urban management, water plant and other
industries.
Administration, Water Works,etc.
2.Working Principle
The principle of the sensor is based on Faraday’s law of
electromagnetic induction.
It is installed a pair of detection electrodes on the pipe
wall,where the measurement pipe axis
and magnetic field lines are vertical. When the conductive liquid
cuts magnetic field lines and
produces induced electromagnetic force.Which can be measured by the
two electrodes on the
meter pipe.The result can be calculated by formula: Induced
electromotive force,(flow signal)
E=KBDV
E——Induced electromotive force,V；
K——meter constant；
B——Magnetic flux density,T；
D——Internal diameter of measuring pipe,m；
V——Average velocity of pipe section,m/s.
1MLF Series Electromagnetic Flow Meter
Assume the volume of liquid as qv(m3/s),qv=πD2V/4),so in the
formula E=(4kB/πD)qv=kqv,
K is meter constant,K=4kB/πD.
Actually, the electromagnetic flow meter consists of two parts,
transmitter and sensor, the
measuring electrodes inspect the electromotive force, and transmit
to the converter, the
converter provides excitation current.
E is usually called a flow signal, after processing the flow signal
by converter, output 4~20 mA/
pulse(or frequency) signal which is proportional to the flow rate,
then the flow rate recording,
adjusting can be achieved.
3. Quick Details
MLF electromagnetic flowmeter is explosion-proof design.
Function of low conductivity measurement.
There are nine languages options to meet the needs of different
customers.
It has the function of self-regulation and self-examination.
Different outputs are optional: Hart,RS485 Profibus,4-20mA,
frequency, pulse.
4. Specification
| MLF Type | Divided Type | Integrated Type | Explosive Proof Integrated Type | Battery Powered Type | Heat Energy Type |
| Accuracy | ±0.2% or ±0.5% |
| Pipeline Diameter | DN10-DN2000 | DN10-DN600 | DN25-DN2000 |
| Flange | GB, ANSI, JIS, BS, Others |
| Pressure | DN10-DN600 1.0 1.6 2.5 4.0MPa |
| DN700-DN2000 0.6 1.0 1.6MPa |
| Liner Material | CR, PTFE, PU, Hard Rubber, PFA, FEP(F46) |
| Conductivity | ≥5µs/cm(Please contact us if it is less than 5µs/cm) |
| Electrode | 316L SS, Hb, Ta, Ti, Hc, Tungsten Carbide, Others |
| Protection Class | IP65, IP66, IP67, IP68 |
| Medium Temperature | -25~180℃
(Please refer to liner material) | -25~80℃(Please refer to liner material) | -25~180℃
(Please refer to liner material) |
| Ambient Temperature for Accuracy Influence | <±0.1%/10℃ or <±0.25%/10℃ at the ambient temperature of -25~60℃ |
| Repetability | ≤±0.1% or ±0.25% |
| Analog Output Error | ≤±0.02mA |
| Velocity | 0.3~10m/s |
| Electrical connection | M20x1.5 Seal Cartridge, GB1/2, NPT1/2 |
| Output | 4-20mA, Pulse, RS485, Hart, Profibus |
5. Selection of Liner Material
| Liner Material | Main Performance | Application |
| PTFE | 1 It has the most stable chemical properties in plastics, resistant
to boiling hydrogen chloride and sulfuric acid, nitric acid, aqua
regia, strong alkali and various organic solvents, but not
resistant to chlorine trifluoride, high temperature nitrogen
trifluoride, liquid fluorine, and liquid oxygen And ozone
corrosion. 2 Low wear resistance. 3 Low negative pressure resistance. | 1. -25~140℃ 2. Strong corrosion medium, like strong acid and alkali 3. Healthcare medium |
| CR | Oil proof, solvent resistance, oxidatite resistance and the
resistance to the erosion of common medium like acid, alkali, salt,
etc. | 1. ＜80℃ 2. Be able to measure sewage and mud |
| PU | 1. Very good abrasive resistance, flexibility. 2. Low acid and alkali resistance. | 1. ＜65℃ 2. Neutral strong abrasion resistance medium |
| Hard Rubber | 1 Room temperature resistance, hydrochloric acid, acetic acid,
oxalic acid, ammonia, phosphoric acid and 50% sulfuric acid, sodium
hydroxide, potassium hydroxide 2 Avoid strong oxidants | 1. ＜80℃ 2. General acid, alkali, salt solution |
| PFA | 1. Can be used for most corrosive medium like acides, alkalis, and
strong oxidant. 2. High material strength, resistance to aging, better than PTFE,
EFP in high temperature 3. Injection molding for higher negative pressure | 1. 40~180℃ 2. Strong corrosion medium, like strong acid and alkali 3. Healthcare mdium |
| FEP(F46) | 1. Hydrophobicity and non-viscous 2. Corrosion resistance is inferior to PFA 3. Negative pressure | 1. 40~180℃ 2. Strong corrosion medium, like strong acid and alkali 3. Healthcare mdium |
6. Selection of Electrode Materials
| Electrode Material | Main Performance |
| 316L | Good nitric acid corrosion resistance, <5% sulfuric acid, acetic
acid, alkaline liquid, sulfite under certain pressure, sea water,
acetic acid, etc. corrosion at room temperature, can be widely used
in petrochemical urea, vinylon, etc. |
| Hb | Good resistance to all hydrochloric acid with a concentration lower
than the boiling point, and also resistant to corrosion by
non-oxidizing acids, alkalis, sulfuric acid, phosphoric acid,
hydrofluoric acid, and organic acids. |
| Hc | Corrosion resistance to oxidizing acids, such as nitric acid, mixed
acids. A mixture of chromic acid and sulfuric acid, oxidizing salts
such as Fe3+, Q3+, and some other oxidizing agents, such as a
mixture of hypochlorite solution and seawater at higher than normal
temperature. |
| Ti | Resistance the corrosion of seawater, various chlorides,
hypochlorite, oxidizing acid(including fuming nitric acid), and
organic acid or alkali, but don't be resistance to the corrosion of
pure reducint acid(like sulfuric acid, hydrochloric acid). But if
acid includes oxidants(like nitric acid, Fe3+, Q3+), the corrosion
resistance will decrease. |
| Ta | Good corrosion resistance similar to glass. Resistance to the
corrosion of chemical medium(including hydrochloric acid and
fumiing sulfuric acid), but can not be used for sodium hydromide
fluid. |
| Pt-Ir | Have good corrosion resistance of all acid, and can be resistance
to the corrosion of alkali, all salt except aqua regia, ammonium
slat and few other medium |
| Tungsten Carbide | For pulp and sewage, good resistance to solid particle
interference. |
7. Dimensional Sketches
a. Dimension of Converter
Divided Type
Integrated Type
Battery Powered Type
b. Dimension of Sensor
| Pipeline Diameter | Dimension |
| L | W | H |
| 15 | 160 | 95 | 130 |
| 20 | 160 | 105 | 137 |
| 25 | 160 | 115 | 150 |
| 32 | 160 | 135 | 160 |
| 40 | 200 | 145 | 175 |
| 50 | 200 | 160 | 185 |
| 65 | 200 | 180 | 205 |
| 80 | 200 | 195 | 215 |
| 100 | 250 | 215 | 235 |
| 125 | 250 | 245 | 275 |
| 150 | 300 | 280 | 300 |
| 200 | 350 | 335 | 355 |
| 250 | 400 | 400 | 405 |
| 300 | 500 | 455 | 460 |
| 350 | 500 | 515 | 520 |
| 400 | 600 | 575 | 580 |
| 450 | 600 | 635 | 630 |
| 500 | 600 | 710 | 685 |
| 600 | 600 | 835 | 795 |
| 700 | 700 | 905 | 910 |
| 800 | 800 | 1020 | 1030 |
| 900 | 900 | 1120 | 1120 |
| 1000 | 1000 | 1245 | 1250 |
| 1200 | 1200 | 1465 | 1470 |
