Among the types of continuous water level sensors, the hydrostatic pressure continuous level sensor has the lowest cost and is quite easy to install and use. Continuous water level sensor by hydrostatic pressure method has the same principle as differential pressure water level sensor. There is a slight difference that the sensor body is dropped inside the liquid tank and there is a cable that transmits the 4…20mA signal to the outside.
The sensor will measure based on the principle that the height of the water column will create a pressure on the lower surface, the pressure on the sensor membrane and the actual pressure outside. A property of water pressure is that for every 10m of water, a pressure of about 1 bar is generated. It does not depend on the volume and radius of the tub, but only on the height and weight of the water.
It is this pressure difference that helps us to know the level inside the tank.
However, the hydrostatic level sensor usually measures accurately for the type of tank with a linear width of the wall, ie the width of the tank does not change.
Besides measuring the level by hydrostatic pressure, the solution of continuous level measurement by ultrasonic waves is equally optimal. Continuous ultrasonic level measurement is often applied as an obstacle sensor, measuring the level of wastewater, river water, clean water, other liquids similar to water and solids.
General principle Ultrasonic level sensor will emit electromagnetic waves continuously, this electromagnetic wave probably propagates with very high speed of 3×10ˆ8m/s equal to the speed of light. When the electromagnetic wave hits the liquid-solid surface, it will reflect a wave signal. That is the reflected wave, the reflected wave will go back towards the sensor. At this time, the receiver of the sensor will receive the wave. The signal converter in the sensor will calculate the distance that the wave has traveled and from there convert it into a 4…20mA signal corresponding to the liquid – solid level.
The feature of this sensor line is that it measures according to the principle of non-contact measurement, so it can measure most of the highly corrosive substances and areas with large flows such as rivers, streams, and canals. Because of non-contact measurement, this sensor line usually has a fairly long life.
In this article, our company would like to introduce to our customers 2 lines of specialized products for measuring the level of liquid – solid continuous hydrostatic and ultrasonic waveforms of VN-TECH we distribute exclusively in Vietnam.
The first is the BDsensor LMK 307 product.
This is a line of products for continuous level measurement of hydrostatic liquids.
Sensor body made of 316L . stainless steel
Membrane made of ceramics Al2O3 96 %
Sensor wire PVC, PUR, FEP
Capable of measuring almost all types of similar liquids such as water, wastewater, clean water, rivers, lakes, canals, wells, etc.
With high accuracy only ±0.5%FSO . error
For measuring ranges up to 250 mH2O.
Full IS Ex SIL2 explosion standard for gas and dusty environments.
Along with that, a rather small diameter of only 27 mm for applications of measuring underground water wells or small sized tanks is very reasonable.
Especially with the installation method is sinking, so customers only buy and use immediately without having to process tanks or install many locations.
The second is the ACS USP4 ultrasonic waveform level sensor line.
This is a line of non-contact liquid-solid level sensors connected to external threads or cables with relatively small size, which can be installed in narrow slots, photometric wells.
With a measurement error of only ±0.2%FSO .
Measuring range up to 8m
PVD, FPOM, PA, NBR, FPM, PUR materials are suitable for all measuring applications requiring high corrosion resistance and hygiene.
And with built-in lightning protection, USP4 is suitable for outdoor use.
And here are some basic parameters and reference prices for the two product lines above: