What electrode is used for electromagnetic flow meter matching for acidic and alkaline industrial wastewater?-Flow Measurement and Intelligent Measurement and Control

What electrode is used for electromagnetic flow meter matching for acidic and alkaline industrial wastewater?

2022-10-12

The wastewater discharged by industrial production enterprises, some are acidic, some are alkaline, some are oxidizing, some are corrosive, some are particulate impurities... Generally, electromagnetic flow meters are used for flow control and measurement. But there are 316L, HaC, HaB, tantalum, titanium, platinum iridium alloy, and tungsten electrodes for electrode flow meters. How should we choose so many electrodes? Is it related to the pH value of the medium?

Today, Weifang Aobo Instrument will introduce the electrode selection of intelligent ABDT-LD electromagnetic flowmeter, as shown in the following figure.

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℃
Polyneoprene rubber	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℃
Urethane rubber	2. High strength,good tear resistance, but the acid and alkaline resistance are poor.	1. Generally long-term temperature resistance≤ 60℃

When using an electromagnetic flow meter to measure liquid flow, the appropriate electrode should be strictly selected according to the diagram above, otherwise it may cause electrode damage, inaccurate measurement, and thus cause certain economic losses. If you have any selection needs, you can contact us, and Weifang Aobo Instrument will be happy to serve you.

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