The external liquid level switch can easily monitor or control the liquid level. The external liquid level switch is mainly used to monitor the liquid level of the storage tank, realize the upper and lower limit alarm or monitor whether there is medium in the pipeline (dry state protection). It can be applied to the liquid level process control of medicine, petroleum, chemical industry, electric power, food and other industries.

At present, there are ultrasonic wave and sonar wave in the external ultrasonic liquid level monitoring. The high-frequency ultrasonic pulse generated by its sensor (probe) can pass through the container wall. This pulse will propagate in the container wall and liquid and will be reflected back.

Through the detection and calculation of this reflection characteristic, we can judge whether there is liquid in the container at the monitoring point. At the same time, the liquid level switch can output relay signals to the subsequent electrical appliances or other equipment, so as to monitor or control the liquid level. The externally attached liquid level switch can be actively adjusted, easy to operate, easy to install, safe and reliable, free from repair, non-toxic and environmental protection. It has resistance to sewage and is widely used in domestic, factory and mine pools, oil, acid and alkali pools, barrels, tanks, irrigation and other containers.

If two controllers are connected. One is put into the water tower and the other is put into the well to operate the water pump, which can avoid damaging the water pump equipment due to the lack of water source and opening the empty pump; Three controllers can also be connected in series, one to the water tower, the other to the filter and one to the river (well), which can be controlled together, so as to avoid damage to the water pump equipment due to lack of water source; Three controllers can also be connected in series, and one can be discharged into the river (well) to control two water pump equipment together.

The external ultrasonic liquid level switch provides a solution for the level measurement of containers, especially high-pressure, corrosive and closed containers. The probe is attached to the outer wall of the container, and the single point level measurement can be completed without drilling. This technology is not affected by the medium pressure, temperature, foam, gas, reflection coefficient and other factors, so it is suitable for  engineering control of various liquid levels of toxic and highly corrosive dangerous liquids in the pharmaceutical, petroleum, chemical, electric power, food and other industries.

Advantages of external liquid level switch:

1. Convenient installation: The new single probe mode is adopted, which makes the installation more convenient and avoids repeated verification.

2. Reliable and durable: There are no mechanical moving parts in sensors and instruments, which are strictly sealed and isolated from the outside world without wear or corrosion.

3. Widely used: It has nothing to do with the pressure, temperature, density, dielectric constant, viscosity and corrosivity of the measured medium.

4. High safety: It is very safe not to touch the liquid and gas in the tank when measuring toxic, corrosive, pressure, flammable, explosive, volatile and easy to leak liquid.

5. Built-in temperature sensor: Monitor the temperature change for 24 hours, and can also carry out temperature compensation.

6. Handheld meter: Debug the instrument, detect the probe state and upgrade the software.