Home > Knowledge > Content

What should be noted to choose the level gauge

Apr 10, 2019

What should be noted to choose the level gauge

When we are involved in a system engineering, 

we need to know about civil engineering, instrumentation, self-control, etc., 

but for some new friends, the choice of liquid level meter is not proficient. 

Xi'an Huaheng Instrument tells everyone about the matters to be noted by the novice to choose the level gauge.


Common instruments and working principle:

1, Float level switch

Principle: Usually, a small or multi-point reed switch is set in the sealed non-magnetic metal,

or engineering plastic tube, 

and the float ball with the built-in magnetic system is fixed on the relevant position of the reed switch in the main body tube, 

so that the floating ball is fixed. 

Floating up and down within the range, 

the magnetic system in the float ball is used to trigger the closing,

or opening of the reed switch through the body tube,

to generate a switching action to achieve the purpose of controlling the liquid level.

2, Magnetic flap level gauge

Principle: Magnetic flap level gauge (also known as magnetic float level gauge),

is developed based on buoyancy principle and magnetic coupling. 

When the liquid level in the measured container rises and falls, 

the magnetic float in the body tube of the liquid level gauge also rises and falls, 

and the magnetic steel in the float is transmitted to the magnetic flip column indicator,

through magnetic coupling, driving the red and white flipping column to flip. 

when the liquid level rises, the column turns from white to red. 

When the liquid level drops, the column turns from red to white, 

and the red-white junction of the indicator is the actual height of the liquid level inside the container,

thus achieving a clear liquid level. 

3, Static pressure level gauge

Principle: 

The two-wire level transmitter of the static pressure level gauge,

consists of a special air-conducting cable with a built-in capillary hose, 

a pressure-resistant connector and a probe. 

The probe configuration of the static pressure level gauge,

is a stainless steel core with a diaphragm at the bottom,

and is covered by a perforated plastic housing. 

The liquid level measurement of the static pressure level gauge is actually the difference,

between the hydrostatic pressure on the probe and the actual atmospheric pressure, 

and then the ceramic sensor (attached to the stainless steel film),

and the electronic component convert the pressure difference into 4~ 20mA output signal.

static pressure level gauge

4, Radar level gauge

Principle: 

The radar level gauge is a general-purpose radar level gauge. 

It is based on the time-stroke principle of the measuring instrument. 

The radar wave runs at the speed of light, 

and the running time can be converted into a level signal by electronic components. 

The probe emits high-frequency pulses and propagates along the cable.

When the pulse encounters the surface of the material, 

it is reflected back and received by the receiver in the meter, 

and the distance signal is converted into a level signal.

5, Ultrasonic level gauge

Principle: 

The working principle of the ultrasonic level meter is,

that the ultrasonic transducer (probe) emits high-frequency pulse sound waves. 

When the surface of the measured object (material) is reflected and folded back,

the reflected echo is received by the transducer and converted into an electrical signal. 

The propagation time is proportional to the distance from the sound wave to the surface of the object.


Xi'an Huaheng Instrument Tips: Understand the working principle of different models of liquid level gauges, you can purchase them according to your needs when you choose, and avoid the liquid level meter that you bought back does not meet the requirements. Want to know more about the double flange level gauge, single flange level gauge, pressure transmitter, differential pressure transmitter, etc., please contact us: 029-89016663.