Explosion-proof electromagnetic flowmeter

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Explosion-proof type electromagnetic flowmeter is 50 ~ 60 s of the 20th century has been developed r…

Products overview:
ZW - LDE seriesExplosion-proof electromagnetic flowmeterIs installed in the inflammable and explosive occasions, a more than ordinary electromagnetic flowmeter explosion-proof function, and the shell material is better than normal.It is a kind of according to Faraday's law of electromagnetic induction measuring volume flow tube conductive medium induction meter, MCU embedded technology, digital excitation, at the same time in the electromagnetic flow meter adopting CAN field bus, the technology to meet the domestic advanced level.Flow meter in addition to the general conductive liquid flow can be measured, can also be measured liquid-solid two phase flow, high viscosity fluid and salt, strong acid, strong alkali liquid volume flow.
Second, the working principle:
ZW - LDE seriesExplosion-proof electromagnetic flowmeter based on Faraday electromagnetic induction principle, with the sounding pipe axis and the magnetic field lines in the vertical tube wall installed on a pair of detecting electrodes, when conducting liquid along the measuring tube axis movement, conductive liquid cutting lines of magnetic force induced electric potential, the induction electric potential by two detection electrodes detection, numerical size and flow into a direct ratio, its value is: E = KBVD type:
E - induction electric potential;
K - factor related to the magnetic field distribution and the axial length;
B - magnetic induction intensity;
V - conductive liquid average flow velocity;
D - electrode gap;(the measuring tube diameter)
Sensor will be induced potential E as traffic signal, sent to the converter, amplifying, transform filter with a series of digital processing, USES dot matrix LCD display with backlight instantaneous flow and cumulative flow.Converter has 4 ~ 20 ma output, alarm output and frequency output, and is equipped with RS485 communication interface, and supports HART and MODBUS protocol.
Applications:
ZW - LDE seriesExplosion-proof electromagnetic flowmeter is mainly used to measure volume flow of conducting liquid and slurry in the closed pipeline.Such as water, sewage, slurry, pulp, all kinds of acid, alkali, salt solution, food slurry, etc., widely used in petroleum, chemical, metallurgical, textile, food, pharmaceutical, paper making industries and environmental protection, municipal administration, water conservancy construction and other fields.
Four, the main features: 
1, instrument structure is simple, reliable, have no moving parts, working life is long;
2, no closure choke parts, there is no loss of pressure and fluid blocking phenomenon;
3, no mechanical inertia, fast response and good stability, can be applied to automatic testing, adjusting and SPC system;
4, the measurement precision is not affected by the type of measured medium and its temperature, viscosity, density, the influence of physical parameters such as pressure;
5, adopt ptfe or rubber lining material and Hc, Hb, 316 l, the different combination of electrode materials such as Ti can meet the needs of the different media;
6, with pipeline, plug-in, such as a variety of flow meter type;
Block 7, using EEPROM memory, measuring operation safe and reliable data storage protection;
8, integration and separation of two types;
9, high-definition LCD backlit display.
Five, the technical parameters:
1, precision instrument: pipeline magnitude 0.5, 1.0;Plug in 2.5 on the Richter scale;
2, measuring medium: conductivity is greater than 5 mu S/cm of various liquid and liquid-solid two phase flow;
3, velocity range: 0.2 ~ 8 m/s;
4, work pressure: 1.6 MPa;
5, environmental temperature: - 40 ℃ ~ + 180 ℃ or less;
6, the rubber material: lining 65 ℃ or less;
7, explosion-proof marks: Exmibd Ⅱ BT4;
8, explosion-proof number: GYB01349;
9, outside magnetic interference: 400 a/m or less;
10, shell protection: integration type: IP65;
11, points out: sensor IP68 (5 meters) underwater;
12, converter: IP65;
13, output signal: 4 ~ 20 ma DC, 0 ~ 750 Ω load resistance;
14, communication output: RS485 or CAN bus;
15, electrical connections: M20 x 1.5 internal thread, phi 10 cable hole;
16, power supply voltage: 90 ~ 220 v AC, 24 V.D C + / - 10%;
17, the power consumption: vasdlde 10 or less.
Six, the structure form:
1, the sensor:
Sensor is mainly composed of measuring tube and electrode, excitation coils, iron core, magnetic yoke and shell.
A, measuring catheter: by stainless steel tube, the lining and the connecting flange, as the carrier of measured liquid measurement working conditions on site.
B, measuring electrode: installed in the measuring tube inside wall, and the axial direction perpendicular to a pair of electrodes to measure liquid signal generation.
: c, excitation coil in a magnetic field measurement of intraductal two excitation coil.
D, iron core and magnetic yoke: the excitation coil of the magnetic field generated import liquid, and the magnetic circuit.
E, shell: instrument packaging.
2, the converter:
Is the smart secondary table, it will flow signal amplification processing microcontroller after operation, can display flow, total amount, and can output pulse and analog current signal, used in the measurement or control of fluid flow.
3, product assembly form:
It into a shape and size in two forms.
A, a shape: mounted sensors and switches.
B, size: separation installation sensor and converter, through the connecting cable form flow metering system.
C, in order to adapt to the measurement demands of the different medium, the lining of sensor and electrode materials can have many choices.
Seven, main advantages and disadvantages:

Main advantages are as follows:
1, the flow sensor structure is simple, the measuring tube has no moving parts, no obstacles to fluid flow throttling components.So when the fluid flow through timing does not cause any additional pressure loss, flow meter is running in the energy consumption of zui low flow meter.
2, measurable smudges medium, corrosive medium and clouding the liquid-solid two phase flow of traffic.This is due to internal unimpeded flow meter tube parts, and the measurement of body contact is sounding pipe lining and electrode, the materials can choose according to the nature of the current body.For example, made from poly three fluoride or ptfe lining, can measure all kinds of acid, alkali, salt and other corrosive medium.Adopt wear-resisting rubber lining, is especially suitable for measuring with solid particle slurry, water slurry, wear a large liquid-solid two phase flow and various liquid with fiber and pulp suspension.
3, is a kind of volume flow measuring instrument, in the process of measurement, it is not affected by the temperature of the measured medium, viscosity and density with conductivity (in a certain range.Therefore, electromagnetic flowmeter only after water calibration, it can used to measure the conductivity of liquid flow.
4, the output of the meter only is proportional to the average flow velocity of the measured medium, and under the symmetric distribution of flow state (laminar flow and turbulent flow).So the electromagnetic flowmeter range very wide range, the measurement range can be up to 100:1, some even up to 1000:1 working flow range.
5, no mechanical inertia, responsive, can measure the instantaneous pulse flow, also can measure the rate of flow of positive and negative two directions.
6, industrial use very wide range of the calibre of the electromagnetic flowmeter, from a few millimeters to a few meters, and the domestic existing diameter up to 3 m's real flow calibration equipment, which laid a foundation for the application and development of electromagnetic flow meter.
There is still the main deficiencies.
1, cannot be used for measuring gas, steam and liquid contains a lot of gas.
2, low cannot be used to measure the conductivity of liquid medium, such as the petroleum products or organic solvent such as medium, the electromagnetic flowmeter is powerless.
3, due to the measuring tube lined with the limitation of materials and electrical insulation materials, can not be used in measuring high temperature medium;If without special treatment, also cannot be used for the measurement of low temperature medium, in order to prevent the measuring tube condensation (frost) destruction of insulation.
4 the influence of electromagnetic interference, vulnerable to the outside world.
Eight, the choice of installation environment and precautions:
In order to make the transmitter work stability, when choosing installation environment should be paid attention to the following requirements:
1, try to avoid strong ferromagnetic objects and concrete equipment of electromagnetic field (such as a big motor, transformer, etc.), so as to avoid the magnetic field of magnetic field effect sensor and traffic information.
2, should be installed in a dry and ventilated place, should not be in damp, easy seeper place of installation.
3, should try to avoid weathered, avoid environmental temperature is higher than 45 ℃ and relative humidity is more than 95.9%.
4, choose to facilitate maintenance and convenient place.
5, flow meter should be installed in the pump back end, never on the suction side of the installation;The valve should be installed in the downstream flow meters.
Note:
1, try to avoid the ferromagnetic objects and equipment with strong electromagnetic field, in order to avoid the magnetic field of magnetic field effect sensor and traffic signals.
2, should be installed in a dry and ventilated place, avoid sharp, environmental temperature should be in 20 ~ + 60 ℃, relative humidity is less than 85%.
Shall have plenty of space around 3, flowmeter, easy to install and maintain. 
Nine, how to correctly choose electromagnetic flowmeter installation points:
1, choose straight pipe full of liquid, such as line of vertical section (it is advisable to flow from the bottom up) or fluid-filled pipes (zui throughout the line it is advisable to lower), in the process of installation and measurement, the full package shall not happen;
2, flowmeter measurement position should fall in more than 5 d and downstream straight section of 3 d;
3, choice of measurement point should be as far as possible away from the pump, valve and other equipment, to avoid the interference of measurement;
4, choice of measurement point should as far as possible away from the power station, strong magnetic field interference sources, etc.
Ten, installation requirements:
1, the flowmeter should be installed in the lower part of the horizontal and vertical place, avoid installed in the pipeline zui highs and vertical section;
2, the electromagnetic flowmeter should be installed in the line up;
3, electromagnetic flowmeter in open discharge pipe installation, the lower part of the should be installed in the pipeline;
4, if the pipe head more than 5 m, downstream of the electromagnetic flowmeter installation exhaust valve;
5, control valve should be installed on the downstream side of the sensor and the cut-off valve, and should not be installed in the upstream of the electromagnetic flowmeter;
6, the electromagnetic flowmeter can't import and export, installed in the pump should be installed in the pump outlet;
7, when measuring well flow meter installed in the way.
Eleven, notable matters of installation:
1, the axis of the measuring electrode must be similar to horizontal direction;
2, measuring the pipe must be completely filled with liquid.
3, the front of the meter should have 5 x D for flow meter diameter (D) the length of the straight pipe, the rear zui to have less 3 x D for flow meter diameter (D) the length of the straight pipe;For the convenience of installation and disassembly, installation of piping expansion joints after can be in the electromagnetic flow meter; 
4, the direction of fluid flow and the direction of arrow flowmeter;
Five should have can be damaged by vacuum meter, the pipe lining, special attention should be paid;
6, near the flow meter should be no strong electromagnetic field;
7, shall have plenty of space, near the flowmeter to installation and maintenance;
8, if measuring pipeline vibration, the electromagnetic flowmeter should be fixed on both sides of bearing;
9, when measuring the mixed liquid of different medium hybrid point and the distance between the flowmeter zui to have less 30 x D for flow meter diameter (D) length;
10, cleaning and maintenance for the convenience of the flowmeter, the by-pass pipe should be installed, and the electromagnetic flowmeter and ensure before 5 d after 3 d straight pipe;
11, such as the installation of ptfe lining flow timing, two flange connection application torque wrench and tighten the bolt, otherwise easy to crush ptfe lining.

12, main technical data:

1, the whole machine and the technology of sensor data:

2, converter technology data:

3, the choice of the lining:

4, import protection flange and the choice of grounding flange ring (or ground) :

5, the choice of electrode:

13, correct selection:

Instrument selection is very important work in instrumentation, relevant data show that the instrument in two-thirds of faults in the practical application is instrument error caused by selection or wrong installation, please pay special attention to.

1, collect data:

By measurement of body composition;
Large flow, small flow;
Z high work pressure;
, z z high temperature low temperature;

2, range scope confirmation:

General industrial use measured medium velocity of electromagnetic flowmeter with 2 ~ 4 m/s advisable, under special circumstances, z low velocity should not be less than 0.2 m/s, high z should be not more than 8 m/s.If the medium containing solid particles, commonly used flow rate should be less than 3 m/s, prevent excessive friction lining and electrode;For viscous flow, the velocity can choose more than 2 m/s, larger velocity help eliminate electrode automatic on the effect of viscous material, to improve accuracy of measurement.

Under the condition of the range of Q have been identified, according to the velocity V can be decided to the size of the flow meter diameter D, the range of the values calculated by the next type:

Q = PI D2V / 4
Q: flow (㎡ / h) D: pipe diameter V: velocity (m/h)

Electromagnetic flow meter range of Q zui flow value should be greater than expected, the flow of the normal value in a full scale slightly greater than the flowmeter calibration 50 is advisable.

3And the reference flow range:

14, selection of coding:

15, design selection and ordering information:

1, the measured medium: name, composition, status, electrical conductivity and electrical conductivity;

2, working temperature (℃);

3, work pressure (Mpa);

4, the pipe diameter (DN), the smallest, normal, scope of quantity (m3 / h);

5, corrosion resistance, wear resistance, whether there is a negative pressure;

6, installation requirements and the environment: a body or fission, signal output, communications, power supply;

7, installation environment: protection grade and explosion-proof requirements.

After-sales service commitment:

1, from the date of signing of the contract, I in the way provided for products of the company offers free maintenance and maintenance service, commitment to lifelong maintenance service;

2, jiangsu wei measurement and control instrument co., LTD. Sales manager will be in regular contact with customers, understand the usage of products, and solve the problems of the customers to use in the process of produce, free of charge to provide technical support;

3 the man-made damage is found, the warranty period, our company is responsible for the maintenance, and the resulting maintenance fee;

4, product quality problems or are not satisfied with product, the user can choose unconditional return, wei tt&c don't charge any fees, appear quality problem, bear the freight back and forth.