Friday, June 21, 2019

The principle and comparison of several level gauges for different price grades.


First, the name: magnetostrictive level gauge

Measuring principle: The electromagnetic wave is transmitted back from the top of the tank to the magnetic floating ring along the waveguide, and the liquid level is calculated according to the echo time.

Features: High precision.

Disadvantages:
1. It can measure high viscosity liquid and mud;

2. The antenna is immersed in the liquid to be tested or its saturated vapor, and is not suitable for the measurement of pressure, corrosion, self-polymerization, flammable, aseptic, high-purity, toxic,  high-viscosity liquid.

3, hot fire hole installation.

Safety: It is not safe to measure pressure, corrosion, toxic, and flammable liquids.

Price: high

Second, the name: capacitance level gauge, RF admittance level gauge

Measuring principle: The probe is inserted into the liquid from the opening of the tank top, and the change of the probe rod capacitor or admittance caused by the change of the liquid height is measured to calculate the liquid level.

Features: The measured capacitance or admittance is affected by the liquid dielectric constant, conductivity, and residual liquid, resulting in errors.

Disadvantages:
1. The on-site liquid is required to calibrate the full scale, and the non-linear error is more obvious.

2, must be immersed in liquid measurement, not suitable for pressure, high purity,  corrosion, flammable, self-polymerization, sterile, toxic , high viscosity liquid measurement.

Safety: It is not safe to measure pressure, corrosion, toxic, and flammable liquids.

Price: low to medium

Third, the name: magnetic flap type liquid level gauge
Measuring principle: The magnetic steel of the buoy in the connecting tube outside the tank attracts the color outside the connecting tube to indicate that the small iron piece is inverted to display the liquid level.

Features: Intuitive.

Disadvantages:
1. After using for a period of time, the color indicates that the small iron piece string will be turned upside down;

2. After a period of use, the buoy will become stuck.
Safety: It is not safe to measure pressure, corrosion, toxic, and flammable liquids.
Price: medium / high (instrument, connected pipe valve, total cost of maintenance)

This article is from Allicdata Electronics Limited

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