Flowmeter Coding System Instruction

LLJDZ Series Electromagnetic Flowmeter

Features

01. Nominal diameter range: DN10～1000
02. Nominal pressure: Flange type normal PN16bar (Dn≤300), PN10bar (DN＞300)
                                    special PN6, 10 (DN≤300), 16 (DN＞300), 25, 40, 63, 100, 160, 260bar
03. Suitable medium: Electrical conductivity＞20μs/cm (micro Siemens/cm) liquid, such as water, sulfuric acid, hydrochloric acid, etc.
 Attention: Pure water is not suitable for this flowmeter
04. Ambient temperature: -15～75℃, relative humidity: 5%～90%
05. Suitable flow speed: 0.5～10m/s
06. Measurement accuracy: Flow speed ≤0.5m/s, it is ±1.5%, flow speed ＞1m/s, it is ±1.0%
07.No baffle in the measuring tube, no pressure loss, not easy to plug
08. Protection grade: Normal IP65, special IP67, IP68 (only split type)
09. Explosion-proof type available, explosion-proof grade: ExdⅡBT6, ExiaⅡCT5
10. Measurement accuracy is not affected by changeable density, viscosity, temperature, pressure, and electrical conductivity of the fluid, 
     sensor induced voltage signal has a linear relationship with the average flow speed, and the measurement accuracy is high
11. LCD backlight displays, can modify parameters online, easy to operate
12. With measuring value power off protection and over-range alarm function, the flow direction of fluid in the sensor can be set, 
     so the sensor installation is not limited by the flow direction of liquid, and can realize bidirectional flow 
13. Shell material: Normal carbon steel (code: C), special SS304 (code: B), SS316 (code: R), SS316L (code: L)
14. Electrode material: Normal SS316L  (code: L), special hastelloy B (code: HB), hastelloy C (code: HC)
      titanium (code: Ti), tantalum (code: Ta), platinum (code: Pt), SS coated with tungsten carbide (code: Pw)
15. Lining material: Normal PTFE (code: F4) , special neoprene (code: NE), polyurethane (code: PU) , teflon FEP (code: F46) , soluble polyteflon (code: PF), ceramic (code: Pn)
16. Normal voltage: AC220V 50/60Hz, DC24V,  allowable tolerance ±10%, customization accepted. Battery operated: DC3.6V (no signal output)

Table of Applicable Medium Temp Range for Common Valve Body and Lining Material 

Note: The maximum applicable medium temperature is subject to the converter and excitation coil, integrated flowmeter conventional maximum applicable medium temperature is 95℃, special is 120℃, above 120℃ needs to select split-type flowmeter.

Principle of Measurement

According to Faraday's principle of electromagnetic induction, a pair of detection electrodes are mounted 
on the vertical wall of the tube of measuring tube axes and magnetic force lines, when the conductive liquid
is moving along axis of measuring tube, the conductive liquid cuts the magnetic field line to generate the 
induced potential.
Induced electromotive force is: E=KBDV          
In the formula: K---coefficient related to magnetic field distribution and axial length
                        B---magnetic induction intensity (unit: T)
                        D---electrode spacing (unit: m)
                        V---average flow speed of conductive liquid (unit: m/s)

When the fluid is measured, it flows through a magnetic field perpendicular to the direction of flow, the flow of conductive fluid induces an electricity proportional to the average flow speed, therefore requires that the electrical conductivity of the flowing liquid being measured is higher than the minimum electrical conductivity. The induced voltage signal is detected through two electrodes and passes through the cable to the converter, after signal processing and related operation, the cumulative and instantaneous flow will be displayed on the converter display.

Components Material Table

Note: □---nominal diameter.

Structure Diagram 

The Main Components of the Product and the Function of Each Component

Electromagnetic flowmeter is mainly composed of magnetic circuit system, measuring conduit, electrode, shell body and converter. The magnetic
circuit system, measuring conduit, electrode and shell body components are called electromagnetic sensors.

The function of each component:
1. Magnetic Circuit System: The role is to produce a DC or AC magnetic field.
2. Measuring Conduit: The function is to let the conductive medium under test pass through, in order to ensure that the magnetic flux is not shunt 
   or short-circuited when the magnetic force line passes through the measuring conduit, measuring conduit must be made of materials with no 
   magnetic conductivity, low conductivity, low thermal conductivity and certain mechanical strength, and can choose non-magnetic materials
   such as SS, glass steel, high strength plastic, etc.
3.Electrode: The function is to elicit the induced potential signal proportional to the measured one. The electrodes are generally made of non-
   magnetic SS and are required to be aligned with the lining level, so that the flow of fluid is not hindered.
4.Lining: The function is to increase the corrosion resistance of the measuring conduit and prevent the induced potential from being short-circuited
  by the wall of the metal measuring conduit.
5.Convertor: Because the induced potential signal generated by the medium flow is very weak, it is greatly affected by various interference factors
 The function of converter is to amplify induced potential signal that electrode detected and convert into a uniform standard DC signal,  such as 4～20mA. DC.

Table of  Flow Rate and Flow Comparison 

Parameter Table of Commonly Used Liquid Electrical Conductivity 

Selection of Minimum and Common Full Scale Flow 

Notes: 1. After the flowmeter is determined, it should be increased by 15%～30% of the full scale value according to the preset maximum flow of the process.
          2.  In actual use, the flow shall not exceed the full scale, and the full scale and minimum flow shall not exceed 20 times within the normal adjustment accuracy range.
          3. The medium's flow speed is appropriate to 2～6m/s, the minimum is 0.5m/s, the maximum is10m/s. The lower the flow speed is, the lower 
               the electromagnetic signal is, and the lower the accuracy of the flowmeter is. The flow speed is too high and the measurement will be inaccurate.
         4. If the medium contains solid particles, the flow speed should be less than 3m/s; for viscous liquid, the flow speed should be a higher value,
             which can help eliminate dirt on the electrode, thereby can improve the measurement accuracy.
         5. Flow calculation formula: Q=900πD2V
             Q---flow (m3/h), D---nominal diameter (m), V---flow speed (m/s)
 Corrosion Resistance Property of Commonly Used Electrode Materials

Main Property of Commonly Used Lining Materials

Outline Dimension (Flange Type)

Note: The flange is manufactured according to JB/T79-1994 standard by default, can also be manufactured according to the standards specified by 
users, such as GB/T9124, HG/T20592, ANSI, JIS, DIN and other standards.

Installation Precautions

01. Try to avoid ferromagnetic objects and equipment with a strong magnetic field (such as large motors, large transformers, etc.), so as not to affect
      the magnetic field of the sensor and flow signal. To avoid interference, the signal line and the power line cannot be laid in the same steel pipe.
02. Should be installed in a dry and ventilated place as far as possible, to avoid the sun and rain, to avoid the ambient temperature above 75℃ and 
      relative humidity greater than 95%.
03. When the medium flow speed does not meet the requirements, should choose the flowmeter with a smaller diameter, then should use an adapter 
      pipe or modify part of the pipe, so that it is the same diameter as the sensor, but the front and back straight pipe section should meet the require-
       ment that the front straight pipe section≥10 times DN, the back straight pipe section≥5 times DN (DN is the pipe diameter).
04. The flowmeter should be installed at the back end of the pump, must not be installed on the suction side, the valve is installed on the downstream 
     side of the flowmeter.
05. The sensor can be installed on the vertical pipe, can also be installed on the horizontal or inclined pipe, but the axis of the two electrodes should 
      be in horizontal state.
06. The medium in the installation position should be full tube flow, to avoid partial tube or gas attached to the electrode.
07. For liquid-solid mixed liquid, it is better to adopt vertical installation, so that the sensor lining wear evenly, thus extending the service life.
08. When the medium is not filled with tube at the installation position of the flowmeter, the method of raising the back end pipeline of the flow-
      meter can be adopted to make it full, it is strictly prohibited to install the flowmeter at the highest point of the pipeline and the water outlet (bu-
      bbles are easily produced at the highest point of the pipeline, and the water outlet is easy to produce non-full pipes, affecting the measurement 
      accuracy of the flowmeter).
09. The flowmeter should be installed in a place that is easy to maintain, it is strictly prohibited to lift the flowmeter converter, if the pipeline has 
      vibration, need to add support.
10.The flow of the medium should be consistent with the arrow direction on the valve body.