The difference between magnetostrictive level gauge and float level gauge

The reed switch is a magnetic levitation ball level gauge. When the magnetic levitation ball floats up and down with the change of liquid level, the magnetic steel inside the float attracts the reed switch at the corresponding position in the sensor, causing the total resistance (or voltage) of the sensor to change. Then, the transmitter converts the changed resistance (or voltage) signal into a 4-20mA current signal output to measure the liquid level remotely. The upper and lower limit alarms can be set on the display instrument to achieve positional control of the liquid level, or other regulators can be used to form a constant liquid level adjustment system.

When the magnetostrictive liquid level gauge is working, the circuit part of the sensor will excite a pulse current on the waveguide wire, and when this current propagates along the waveguide wire, a pulse current magnetic field will be generated around the waveguide wire. A float is installed outside the measuring rod of the magnetostrictive liquid level gauge, which can move up and down along the measuring rod with the change of liquid level. There is a set of magnetic rings inside the float. When the pulse current magnetic field meets the magnetic ring magnetic field generated by the float, the magnetic field around the float changes, causing the waveguide wire made of magnetostrictive material to generate a torsional wave pulse at the position of the float. This pulse is transmitted back along the waveguide wire at a fixed speed and detected by the detection mechanism. The position of the float, i.e. the liquid level, can be determined by measuring the time difference between the pulse current and the torsional wave.

There is a difference in the accuracy level between these two types of liquid level gauges, and the float level gauge design institute does not use it very much (at least our unit is). The reputation of domestic products is also slightly worse, and magnetostrictive ones are more commonly used in oil tank areas

The working principle is two different things, magnetostrictive level gauge is a linear transformation of electromagnetic field. The reed switch is mechanically operated, non-linear, and has a step like variation.

Secondly, the accuracy of float level gauges is low, while the accuracy of magnetostrictive level gauges is currently the highest among all level gauges, not at the same level!

Another point worth noting is that these two types of liquid level gauges can be designed to have the same structure from the appearance, with a floating ball, sensor, and electronic meter head (which can be standard everywhere). So many unscrupulous merchants will pass off inferior products as good. It is recommended to confirm the accuracy when using it. Even if the accuracy of a short range magnetostrictive liquid level gauge is poor, it will not be less than 1mm. However, no matter how good the reed switch is, it is far from achieving this 5mm accuracy.