Ultrasonic Level Switch, External Mounted (referred to as “external level switch”) is a new type of level measurement alarm device.

HS-ULC Ultrasonic Level Switch-External Mounted

Ultrasonic Level Switch is mainly used to detect the liquid level of the storage tank. It can realize the upper and lower limit alarm or monitor whether there is liquid in the pipeline (dry protection). The material of the storage tank can be various metals, non-metals or non-foamed plastics. The wall thickness can be Up to 70mm.

Ultrasonic level switch is installed outside the tank. No need to open holes in the tank. Non-Contact Measure. The ideal choice for tank level monitoring.

Features of HS-ULC Ultrasonic Level Switch

  1. Wide range of applications. It can be used to measure various liquid media in highly toxic, corrosive, high-pressure, various complex working conditions, and explosive gas environments.
  2. The installation can be without stopping production, unclearing the tank, and keeping the fire. The installation is convenient and the operation is simple.
  3. The instrument works reliably and has stable performance. Strong anti-interference ability.
  4. The meter does not require user maintenance, maintenance-free. Long service life.

Specifications of HS-ULC Ultrasonic Level Switch

Power SupplyDC 24V(18~36V)   0.05A
Repeatability error±2mm
Measurable tank typeHorizontal tank, spherical tank, vertical tank, etc.
Tank wall thickness2-70mm
MaterialCast aluminum
Electrical interfaceDifferent types available for different operating condition
Time lag1-3 seconds
Explosion-proof MarkExdmIICT6
Ingress ProtectionIP65
Output signalRelay output (1 unit single-pole, double-throw control contact is passive nodes)
Relay capacityDC 30V 6A / AC 250V 6A
Diameter of threading holeΦ8mm ( adaptive cable diameter Φ6~8mm )
Ambient temperature-50℃~60℃ (-58 °F – 140 °F)
Ambient humidity15%~100%RH
CertificatesISO  SIL

Extended reading: The Secret of Ultrasonic Level Measurement

Ultrasonic Level Switch Working Principle

Ultrasonic Level Switch Working Principle

The sensor of the external liquid level switch couples the generated high-frequency ultrasonic pulse to the container wall through the couplant.

The pulse will propagate in the container wall and liquid, and will be reflected by the inner surface of the container.
By detecting and calculating the characteristics of the reflected signal, it can be judged whether the liquid level has reached the position where the controller is installed.

The liquid level controller can output a relay signal to facilitate the detection and control of the liquid level.

Ultrasonic technology is not only used to measure level, but also can be used to measure depth.

Ultrasonic Liquid Level Switch Applications

Ultrasonic Level Switch is not affected by factors such as medium density, dielectric constant, conductivity, reflection coefficient, pressure, temperature, precipitation, etc. It is suitable for various liquid levels in the pharmaceutical, petroleum, chemical, electric power, food and other industries Engineering control. Ultrasonic Level Switch is the ideal choice for the detection of toxic, highly corrosive, and dangerous liquid level.

Applied Industries

  • Petrochemical industry
  • Chemical industry
  • Foodstuffs
  • Pharmaceutical industry
  • Marine industry
  • Oil refining industry
  • Refrigeration industry

Applied Medium

Liquefied GasEthyleneHydrochloric AcidNitric AcidSulfuric Acid
PropyleneAqua CarbolisataEdible OilCrude OilLacquer Thinner
BrineButadieneChlorethyleneLight HydrocarbonCaustic Soda Liquid
MethylamineTolueneLight OilGasolineC3
KeroseneXylolOxalic AcidOxiraneAcetone
CarbinolEthanolDimethyl EtherDiethyl EtherDiesel
And More……

HS-ULC Ultrasonic Level Switch is specially used to measure the liquid level of tanks. Because it is installed on the outside of the tank, there is no need to punch holes, which is widely welcomed by customers.

Of course, if your tank already has holes, you can also choose other tank level transmitters.

Such as Liquid level float switch. Liquid level float switch is a commonly used liquid level controller. For water Tank & Pump alarm and level control. Can be divided into Continuous Float Level Sensor and Point Level Float Switch.

The ultrasonic principle can also be used to measure water depth. Please refer to Portable Ultrasonic Water Depth Gauge for water depth measurement.

Ultrasonic Level Sensor Working Principle

The working principle of the ultrasonic level senor: The high-frequency pulse sound wave emitted by the ultrasonic transducer is reflected on the surface of the measured level, and the reflected echo is received by the transducer and converted into an electrical signal. The propagation time of the sound wave is proportional to the distance from the sound wave to the surface of the object. The relationship between sound wave transmission distance S and sound speed C and sound transmission time T can be expressed by the formula: S=C×T/2.

Featured ultrasonic level sensors for tanks

Among various liquid storage tanks, ultrasonic level gauges are the most commonly used level gauges.
For open tanks, ultrasonic level sensors can be installed directly on the top of the tank.
For closed tanks, and an external ultrasonic sensor can be installed at the bottom.

Ultrasonic liquid level sensors use the propagation characteristics of waves in the medium. Ultrasonic transmitter and receiver can be installed at the bottom or top of the tank when measuring the tank liquid level. The emitted ultrasonic waves are reflected at the corresponding interface and received by the receiver. By measuring the time difference between the ultrasonic wave transmission and the reception, the liquid level can be measured.

Read more: Guide: Non-contact Ultrasonic Level Sensing transmitters

Float Level Sensors & Switches

The float level switch is a kind of level switch. The float level switch uses magnetic force to operate. No mechanical connections. The operation is simple and reliable. When the float switch floats the measured medium, the float moves the main body. At the same time, the magnet on the other end of the float will control the magnet on the switch action lever.


Help Center

Ultrasonic level sensor is a monitoring instrument for measuring liquid height, tank height, and material position. The ultrasonic level sensor can adopt two-wire, three-wire or four-wire technology.
The two-wire system is: power supply and signal output are shared.
The three-wire system is: the power supply circuit and the signal output circuit are independent. When using DC 24v power supply, a 3-core cable can be used, and the negative terminal of the power supply and the negative terminal of the signal output share a core wire.
The four-wire system is: when using AC 220v power supply, or when using DC 24v power supply. When the power supply loop and the signal output loop are required to be completely isolated. A 4-core cable should be used.
DC or AC power supply, with 4~20mADC, high and low switch output.
Extended reading: Guide to Ultrasonic Level Transmitters

The function of the liquid level switch is to control the liquid level. For example, the water pump fills the pool with water, and the level switch can make the water in the water tank neither overflow nor empty, and there is always water. “

The ultrasonic sensor can of course measure the water level.
When the ultrasonic level gauge is working, the high-frequency pulse sound wave is emitted by the transducer (probe), and is reflected on the surface of the measured object (water surface). The reflected echo is received by the same transducer (probe) and converted into an electrical signal . The time between pulse sending and receiving (the movement time of the sound wave) is proportional to the distance from the transducer to the surface of the object. The relationship between the distance S of the sound wave transmission and the speed of sound C and the transmission time T can be expressed by the formula: S= CⅹT /2
In addition to using ultrasonic level gauges for water level monitoring, users can also use radardepth water level sensors and other technologies to monitor water level.
Extended reading: Radar Non Contact Water Level Sensor

Ultrasonic level measurement refers specifically to the use of ultrasonic level sensors for liquid level measurement. Ultrasonic level measurement is a non-contact measurement of liquid or solid materials.

Read more about Guide to Ultrasonic Level Transmitters

Ultrasonic Water Level Sensor refers to the ultrasonic level sensor used to measure the water level. Used for industrial liquid tanks, or river water level non-contact monitoring and control.

Read more about Ultrasonic water level sensors for Liquid Tanks-River Level 

Yes. Ultrasonic sensor measuring water level is a common application of the ultrasonic liquid level sensor. It can be used for water storage tanks or river water level measurement.

Liquid level switch, also known as water level switch, liquid level sensor. As the name implies, it is a switch used to control the liquid level.

In terms of form, it is mainly divided into contact type and non-contact type.

Commonly used non-contact switches include capacitive liquid level switches, and contact float-type liquid level switches are the most widely used. Electrode liquid level switches, electronic liquid level switches, and capacitive liquid level switches can also be realized by contacting methods.

Know more about Liquid Level Switch.

Sino-Inst offers over 10 Ultrasonic Level Switches for level measurement. About 50% of these are fuel level meters, 40% is tank level sensor.

A wide variety of Ultrasonic Level Switches for level measurement options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of Ultrasonic Tank Level measurement instrumentation, located in China.