ZRN-LDC electromagnetic flowmeter selection

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Electromagnetic Flowmeter Selection

Instrumentation instrument selection is very important work, the data indicate that the instrument in practical applications have 2/3 Selection of instrument failure is wrong or incorrect installation caused, please pay special attention.

Electromagnetic Flowmeter Selection Explanation Proper selection of electromagnetic flowmeter is a prerequisite to ensure the good use of electromagnetic flowmeters. Shiyao kind of electromagnetic flowmeter selection should be determined based on the physical and chemical properties of the measured fluid medium that bore electromagnetic flowmeter, flow range , lining materials, electrode materials and output current, etc., can meet the requirements of the measured fluid properties and the nature and flow. Measurable fluids: Works seen by the electromagnetic flowmeter can choose the electromagnetic flowmeter to measure the flow of fluid must be electrically conductive, strictly speaking, in addition to the high temperature fluid, any fluid as long as the conductivity is greater than 5μ / cm are the choice of the corresponding electromagnetic flowmeter to measure the flow rate, and therefore the material gas, steam, oil, acetone, etc. can not use non-conductive electromagnetic flowmeter to measure the flow rate. Sensors determine the caliber: Flowmeter flow rate is best . 0.3-15m / s within the range, this time with a user selectable meter diameter pipe diameter using a consistent flow rate of less than 0.3m / s at best a partial increase the flow rate of the instrument parts, use shrink tube method: When the center cone angle diameter pipe is not more than 15oC, it can be considered as part of the straight pipe diameter pipe sections. Integrated or separate type selection: Compact: the site under better environmental conditions, generally use a body, namely the sensor and converter assembled into one.

model	caliber
ZRN-LDC	15~2600
		Code	Electrode material
		K1	316L
		K2	HB
		K3	HC
		K4	titanium
		K5	Tantalum
		K6	Platinum alloy
		K7	Stainless steel coated with tungsten carbide
			Code	Lining material
			C1	Teflon F4
			C2	Poly FEP F46
			C3	Polyvinyl fluoride, ethylene co-FS
			C4	Poly recorded butadiene rubber
			C5	Polyurethane rubber
				Code	Features
				E1	0.3
				E2	0.5
				E3	Level 1
				F1	4-20Madc, load ≤750Ω
				F2	0-3khz, 5v active, variable pulse width output high effective frequency
				F3	RS485 interface
				T1	Std
				T2	High temperature
				T3	Ultra-high temperature type
				P1	1.0MPa
				P2	1.6MPa
				P3	4.0MPa
				P4	16MPa
				D1	220VAC ± 10%
				D2	24VDC ± 10%
				J1	A body structure
				J2	Sub-body structure
				J3	Explosion-proof body structure

• Data collection

① measured fluid ingredients ② maximum flow, minimum flow ③ Maximum operating pressure ④ Maximum temperature, minimum temperature

Range of electromagnetic flowmeters Q should be greater than the expected maximum flow rate, and the normal flow value slightly larger than the 50% full scale of the meter is appropriate.

Instrument Selection

• Confirm range

General industrial electromagnetic flowmeter measured medium flow rate 2 ~ 4m / s is appropriate, in exceptional circumstances, the minimum flow rate should not be less than 0.2m / s, the maximum should not exceed 8m / s.

If the medium contains solid particles, commonly used flow rate should be less than 3m / s, to prevent excessive friction lining and the electrodes; for viscous fluid velocity choose more than 2m / s.

Effect on the flow rate of greater help to electrode attachment automatically eliminate viscous material, helping improve the measurement accuracy.

Q has been determined in the range of conditions, you can determine the size of the diameter D of the flow meter based on the velocity V of the range, the value calculated by the following formula:

Q = πD2V / 4
Q: flow rate (/ h) D: pipe diameter V: velocity (m / h)

Q electromagnetic flowmeter range should be greater than the expected maximum flow rate value, and the normal flow value slightly larger than 50% of full scale flow meter is preferably

Installation Site Selection
In order to make stable and reliable electromagnetic flowmeter, when selecting the mounting location in attention to the following requirements:
1. Try to avoid ferromagnetic objects and devices with strong electromagnetic fields (large electric motors and transformers, etc.), so as not to affect the magnetic field and the magnetic flow sensor signal.
2. should be installed in dry and ventilated place, avoid the sun and rain, ambient temperature should be -20 ~ + 60 ℃, relative humidity less than 85%.
3. The meter should be ample space around, easy to install and maintain.
Electromagnetic flowmeter measurement principle does not depend on the flow characteristics, if there is a certain degree of turbulence inside the pipe and the vortex is generated in the non-measurement area (such as: elbows, tangential limiting or upstream half open valve) is the measurement If there is nothing to steady vortex it will affect the stability and measurement precision measurement, then you should take some measures to stabilize the velocity distribution in the measurement area:
. a increase in the length of straight pipe section before and after;
. b using a flow stabilizer;
c. to reduce the cross section of the measuring point.

Electrode materials selection:

material	Anti-corrosion properties
316L	Application: 1, domestic water, industrial water, raw water wells, municipal sewage. 2, weak corrosive acid, alkali, salt solution
Hastelloy B	Applicable: 1, hydrochloric acid (concentration less than 10%), ammonium hydroxide concentration of the alkaline solution all 2, sodium hydroxide (concentration less than 50%), ammonium hydroxide concentration in the alkali solution all 3, phosphoric acid, an organic acid NA: hydrochloric acid
Hastelloy C	Application: 1, mixed acid such as chromic acid and sulfuric acid mixed solution 2, an oxidizing salts such as Fe ++, Cu ++, seawater NA: hydrochloric acid
Titanium (Ti)	Applicable: 1, salts, such as: (1) chloride (chloride / magnesium / aluminum / calcium / ammonium / titanium, etc.) (2) the sodium, potassium, ammonium, hypochlorite, water 2, the hydrogen concentration is less than 50% of potassium chloride, ammonium hydroxide, barium hydroxide alkaline solution NA: hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, an alkali cyanide barium oxide solution
Tantalum (Ta)	Application: 1, hydrochloric acid (concentration of less than 40%), sulfuric acid and concentrated sulfuric acid (not including oleum) 2, chlorine dioxide, magnesium chloride, hypochlorous acid, sodium cyanide, lead acetate 3, nitric acid (including fuming nitric acid), and other oxidizing acid, the temperature is below 80 ℃ in aqua regia NA: alkali, hydrofluoric acid
Platinum (Pt)	Application: Almost all of the acid, alkali, salt solutions (including fuming sulfuric acid, fuming nitric acid) NA: aqua regia, ammonium salt

Lining Materials:

It should be based on the measured medium corrosive, abrasive and temperature to choose the lining material.

Lining material	name	symbol	performance	The maximum operating temperature	For the liquid	Applicable caliber
rubber	Neoprene	CR	Moderate abrasion resistance is generally low concentrations of acid salt corrosion	(80℃	Water, industrial water, seawater	DN50-2200
rubber	Poly ammonium fat rubber	PU	Excellent wear resistance, acid and alkali poor performance	(60℃	Pulp, pulp slurry, etc.	DN25-500
Fluorine plastic	Poly vinyl chloride	F4 or PTFE	Very stable chemical properties, resistance to boiling hydrochloric acid, sulfuric acid, aqua regia, concentrated alkali corrosion	(180℃	Corrosive liquid acid salt	DN25-1200
	Tetrachlorethylene and hexafluoropropylene Translation: Teflon FEP	F46 or FEP	Chemical properties slightly inferior to F4	(120℃	Corrosive liquid acid salt	DN15-200
	Tetrachlorethylene and ethylene	F4 or ETFE	Chemical properties slightly inferior to F4		Corrosive liquid acid salt	DN250-2200
plastic	Polyethylene	PO	Chemical stability	(60℃	Polluted water	DN50-2200
plastic	PPS	PPS		(110℃	Hot water	DN50-2200

Protection class selection:
1, IP65: Anti-water type, allow faucet water from any direction sensor, water pressure 30kPa, the amount of water 12.5L / s, a distance of 3m.
2, IP68 : Diving, long-term work in the water.
Protection rating should be selected according to the actual situation, the sensor mounted below ground, as is often affected by flooding should be used in IP68, the sensor is installed above ground should be used IP65.
Select additional functions
LDE Basic intelligent electromagnetic flowmeter has a display, output 4-20mA and 0-1kHz alarm function, selected additional functions can be added according to the actual situation.
3, Split installation: The sensor must be installed below ground level or other reasons, you should choose split installation.
4, RD-485 Communication: the need converters and other communications equipment, you need to choose RS-485 communication function.

Flowmeter Protection Level Description

1, IP65: anti-spray type, allowing the tap water from any direction sensor, water pressure is 30kPa, the amount of water to 2.5L / min, a distance of 3m.

2, IP68: diving, long-term work in the water.

Intelligent Electromagnetic Flowmeter protection rating should be selected according to the actual situation, the sensor mounted below ground, often affected by flooding should be used in IP68, the sensor is installed above ground.

Should be used IP65. Electromagnetic flowmeter selection except when needed attention to some issues, when the electromagnetic flowmeter installation also requires attention to some issues regarding installation, please refer customers ZRN-LDC electromagnetic flowmeter installation