High Quality Cheap Water Magnetic Flowmeter
1. Introduction
1. 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.
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 language 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. Selection of Liner Material
| Liner Material | Main Performance | Application |
| PTFE | 1 The most stable chemical properties in plastics, resistant to
boiling hydrogen chloride and sulfuric acid, nitric acid, aqua
regia, strong bases and various organic solvents, but not resistant
to the corrosion of chlorine trifluoride, high temperature nitrogen
trifluoride, liquid fluorine, liquid oxygen and ozone. 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, hydrochloric acid, acetic acid, oxalic acid,
ammonia, phosphoric acid and 50% sulfuric acid, sodium hydroxide,
potassium hydroxide 2. Avoid strong oxidizing agents | 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 |
5. Selection of Electrode Materials
| Electrode Material | Main Performance |
| 316L | Good resistance to the corrosion of nitric acid, ＜5% sulfuric acid
under room temperature, acetic acid, alkaline fluid, sulfite under
certain pressure, seawater and scetic acid, etc. It can be widely
used in petrochemical urea, vinylon. |
| Hb | Good resistance to all concentrations below the boiling point of
hydrochloric acid, but also resistant to non-oxidizing acid,
alkali, sulfuric acid, phosphoric acid, hydrofluoric acid, organic
acid corrosion. |
| Hc | Corrosion of oxidizing acids, such as nitric acid, mixed acids. A
mixture of chromic acid and sulfuric acid, oxidized salts, such as
Fe3,Q3, and some other oxidants, such as a mixture of hypochlorite
solution and seawater above normal temperature. |
| Ti | Resistant to corrosion of seawater, various chlorides,
hypochlorite, oxidizing acids (including fuming nitric acid),
organic acids or bases, but not pure reductive acids (e.g.,
sulfuric acid, hydrochloric acid) etc. but if the acid contains
oxidants (such as 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. |
6. 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 |
7. Instrument Testing & Maintenance
The electromagnetic Flowmeter has the function of self-diagnosis.In
addition to power supply and hardware circuit failures, the system
also gives an alarm to other faults in general use.These messages
are prompted in the lower right corner of the screen.
1 Maintenance and repair.
A) the sensor installation site should meet the requirements of
Section 4, please keep the shell clean and tidy.
B) the transmitter should be placed in a clean, ventilated and dry
place.
C) it needs to be checked every two years, and for high-precision
users, the instrument needs to be submitted for review.
2 Transportation and storage.
A) the equipment must be packed before transportation and handled
carefully during loading and unloading.
B) the storage place must be dry and ventilated to avoid the
erosion of corrosive gases and the ambient temperature should not
be too low or too high.
C) the storage time should not exceed three years.
3. Out-of-the-box inspection.
A) the package cannot be opened with a heavy hammer, be careful not
to damage the instrument.
B) carefully check the contents according to the packing list.
