Low Conductivity Electromagnetic Flowmeter

 

 

Overview

    ABDT-LD series smart electromagnetic flowmeter is a relatively mature liquid measurement instrument suitable for measuring the volume flow of conductivity liquid (conductivity≥5µs/cm) and slurry in closed pipes.It is suitable for various acid,alkali and salt solutions,clear water,sea water,sewage,mud,paper pulp,ore pulp and low conductivity liquid,etc.It is widely used in industrial production process control,energy measurement, environmental protection,sewage treatment and other fields. 4~20mA current signal,pulse signal and it is combined with display, recording instrument, calculator or regulator for detection, calculation,adjustment and control of flow.

 

Principle

    The working principle of the electromagnetic flowmeter is based on the Faraday law of electromagnetic induction. When a conductor moves in a magnetic field,an induced electric potential is generated at both ends of the conductor perpendicular to the direction of the magnetic field.The magnitude of the electric potential is proportional to the motion velocity of the conductor and the magnetic induction strength of the magnetic field.

When the conductive fluid flows at an average velocity of V(m/s) through an insulating catheter with an inner diameter of D(m) containing a pair of measuring electrodes,the pipeline is in a magnetic field with a uniform magnetic induction strength of B (T),then the induced electric potential E(V) is generated on a pair of electrodes.Its direction is perpendicular to the magnetic field.

    When B is a constant, a certain fixed caliber D is also a known number, in formula(3)  (a constant), then formula (3) can be overwritten to(5)

By formula (5) it is seen that the flow QV is proportional to the electric potential E.

 

 Feature

(1) It is not affected by the fluid density,viscosity, temperature and pressure;

(2) No flow resistance parts in the measuring pipe, small pressure loss and low straight pipe section requirement;

(3) Strong anti-interference ability and high precision;

(4) The stability of specific flow measurement of converter and small power loss;

(5) It has various alarm functions,such as air traffic control alarm,excitation alarm and upper and lower limit alarm;

(6) The measurement range is wide and the lining and electrodes have a variety of choices,which can meet the requirements of various conductive fluids;

(7) It uses SMD device and surface installation (SMT) technology,with high circuit reliability;

(8) It can be used for explosion-proof occasions.

 

Parameter

Medium temperature: integrated type 70℃;

Separated type: ≤ 150℃ for temperature resistance according to different lining materials;

Nominal general diameter: DN15-DN1400;

Accuracy grade: grade 0.5;

Maximum flow speed: 15m/s;

Nominal pressure: 1.0MPa,1.6MPa,2.5MPa,4.0MPa,other specifications and standards can be used according to the user’s requirements;

Fluid conductivity: ≥ 5us/cm;

Execution standard: JB/T9248-2015;

Ambient temperature: sensor (-25~60)℃, converter (-10~60)℃

Relative humidity: (5~85)%RH, without condensation;

Shell protection grade:Converter IP65,sensor IP68.

 

 

Electrode material selection

Electrode material	Features and use scope
316L	Applicable:
	1. Domestic water, industrial water, raw water, well water and urban sewage.
	2. Weak corrosive acid, alkali and salt solution.
Haynes metal B	Applicable:
	1. The hydrochloric acid (concentration is less than 10%) and so on non-oxidized acids.
	2. Sodium hydroxide(concentration is less than 50%), all concentrations of ammonium hydroxide alkali solution.
	3. Phosphoric acid, organic acid.
	Not applicable:
	Nitric acid.
Haynes metal C	Applicable:
	1.Mixed acid, such as the mixed solution of chromic acid and sulfuric acid.
	2. Oxidation salts such as Fe+++, Cu++, sea water.
	Not applicable:
	the hydrochloric acid.
Ti	Applicable:
	1. Salt, such as (1) chloride (chloride/magnesium and aluminum/calcium/ammonium/iron, etc.)；(2) Sodium salt,potassium salt, hypochlorite salt, sea water.
	2.Potassium hydroxide, amine hydroxide and barium hydroxide alkali solution whose concentration are less than 50%;
	Not applicable:
	hydrochloric acid, sulfuric acid, phospic acid, hydrofluoric acid and other reductive acid.
Ta	Applicable:
	1. Hydrochloric acid (concentration is less than 40%), dilute sulfuric acid and concentrated sulfuric acid (excluding fuming sulfuric acid);
	2. Chloride dioxide, iron chloride, hypochlorite,sodium cyanide, lead acetate, etc.;
	3. Nitric acid (including fuming nitric acid) and other oxidizing acid, aqua regia whose temperature is less than 80 degrees;
	Not applicable:
	alkali, hydrofluoric acid.
Platinum-iridium alloy	Applicable:
	Almost all acid, alkali and salt solutions (including fuming nitric acid, fuming sulfuric acid)
	Not applicable:
	aqua regia, ammonium salt.
Tungsten carbide	Applicable:
	large worn medium,paper pulp,sewage,resistant to interference of solid particles;
	Not applicable:
	inorganic acid, organic acid, chloride.

 

Lining material selection

Lining material	Main performance	Scope of application
PTFE	1. One of the most stable materials in plastic that can withstand boiling hydrochloric acid, sulfuric acid, nitric acid and aqua regia and it can resist strong acid and a variety of organic solvents.	1. Temperature-resistant ≤ 80℃
	2. Poor wear resistance and adhesion performance.	2. Strong corrosive medium such as acid and alkali.
		3. Sanitary medium.
Polyfluoroalkoxy (PFA)	1. Chemical stability, electrical insulation,  lubricity, non-viscosity and combustible properties are similar to F46, but the PFA material strength, aging resistance and temperature resistance are better than F46.	1. Long-term use  temperature resistance ≤ 150℃.
	2. Good adhesion with metal and better wear resistance than PTFE, F46.	2. It can be used to measure most strong corrosive mediums such as strong acid, strong alkali and strong oxidizer; but it is not for KOH, nitric acid, hydrofluoric acid, etc.
	3. Low smoke, refractory, high temperature resistance and high temperature mechanical strength are higher than PTFE and F46.
PDF-ethylene propylene F46	1. Chemical stability, electrical insulation, lubricity, non-viscosity and combustible properties are similar to PTFE, but the F46 material strength, aging resistance and temperature resistance are better than PTFE.	1. Long-term use  temperature resistance ≤ 110℃
	2. Good adhesion with metal and better wear resistance than PTFE.	2. It can be used to measure most strong corrosive mediums such as strong acid, strong alkali and strong oxidizer, but it is not for KOH, nitric acid, hydrofluoric acid, etc.
	3.Excellent anti-tear  performance.
Polyneoprene rubber	1. Excellent elasticity, good wear resistance.	1.Temperature resistance ≤ 65℃
	2. It has resistance to corrosion of general low concentration acid, alkali and salt medium and it has no resistance to corrosion of oxidation medium.	2.Measure the general water, sewage, mud and mineral slurry.
Urethane rubber	1. Excellent wear resistance and good oil resistance.	1. Generally long-term temperature resistance≤ 60℃
	2. High strength,good tear resistance, but the acid and alkaline resistance are poor.

Outline size

Outline and installation size of the electromagnetic flow sensor (in mm)

 

Installation precautions

Keep a long enough straight pipe section upstream and downstream of the electromagnetic flow sensor (D is the sensor diameter) as required in the figure below.

 

Product Type Selection

 

Liquid Flow and Velocity Table