Non Contact Liquid Level Sensor

The Non Contact Liquid Level Sensor is not in contact with the measured medium. The Non Contact Liquid Level Sensors provided by Sino-Inst is not Gravity Non-contact Liquid Level Sensors. It is the liquid level sensor used in industrial tanks, reservoirs, and open channels. There are mainly ultrasonic level sensors and radar level sensors.

Non Contact Liquid Level Sensor

Featured Non Contact Liquid Level Sensors

Read more about 7 Level Senors for Tank Level Measurement

In the automated production process, in order to ensure the consistency of product quality, the time when the production process is directly monitored and intervened by humans has gone.

Liquid level measurement and monitoring play an increasingly important role. It can be said that liquid level measurement and monitoring It directly affect the quality of the product and even whether the production process can proceed smoothly.

Contact measurement
A measuring method in which the sensing element of a measuring tool or measuring instrument obtains measurement information through direct contact with the measured surface.

Non-contact measurement
Non-contact measurement is based on photoelectric, electromagnetic, and other technologies. Without touching the surface of the object to be measured, a measurement method to obtain information on the surface parameters of the object.

Extended reading: Ultrasonic liquid level sensors

Methods of liquid level measurement:

There are mainly the following methods and principles for measuring liquid levels in the industrial field.

  1. Direct display category. Such as glass tube, glass plate, etc.;
  2. Floating ball class. Such as magnetic flaps, small floats, connecting rod floats, cable floats, side-mounted floats, continuous floats, etc.
  3. Contact induction class. Capacitance level gauge, magnetic to telescopic level gauge, pressure type level gauge, etc.;
  4. Non-contact type. Ultrasonic level gauge, radar wave level gauge, etc.

Guess you like Continuous Float Level Sensor & Switches 

  1. Liquid level measurement of sealed tank
  2. Liquid level detection of fire storage tank
  3. Liquid level measurement of open tank
  4. Liquid level detection in open channels, rivers, reservoirs, etc.

Extended reading: Radar Non Contact Water Level Sensor

Ultrasonic Level Sensor Working Principle

The working principle of the ultrasonic liquid level sensor is:

Ultrasonic transducer (probe) emits high-frequency pulse sound waves, and the surface of the measured level (material) is reflected back. 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.

Read more about: Non-invasive Ultrasonic Tank Level Sensor Working Principle

The relationship between the sound wave transmission distance S and the sound speed C and the sound transmission time T can be expressed by the formula: S=C×T/2.

The probe part emits ultrasonic waves, which are then reflected by the liquid surface. The probe part is received again. The distance from the probe to the liquid (object) surface is proportional to the elapsed time of the ultrasonic wave:
hb = CT2
Distance [m] = time × speed of sound/2 [m]
The temperature compensation formula of sound velocity:
Ambient sound velocity = 331.5 + 0.6 × temperature

Read More about Ultrasonic Level Sensing

Radar Level Measurement: Measuring Principle

Very short microwave pulses with very low energy are transmitted and received through the antenna system. The radar wave runs at the speed of light. The operating time can be converted into level signals by electronic components. A special time extension method can ensure stable and accurate measurement in a very short time.

Electromagnetic waves propagate in the air at the speed of light. The distance between the radar level gauge and the surface of the material can be expressed by the following formula:

D = (1/2)*CT

In the formula: D ———the distance between the radar level gauge and the surface of the material; C ———Speed of light; T ———Pulse time.

Then the liquid level is:   L = E-D

In the formula: L — liquid level; E ———The total height of the tank;  D ———Air height.

Even in the presence of false reflections, the new micro-processing technology and the unique ECHOFOX- software can accurately analyze the level echo. By inputting the size of the container, the distance value can be converted into a signal proportional to the level. The instrument can be debugged with empty positions.

Read More about Non-Contacting Radar Level Measurement

Ultrasonic liquid level sensors realize the non-contact continuous detection of liquid level.

Ultrasonic liquid level sensors echo sounding sensors for measuring liquid level. And converting it to an electrical signal to send to other instrumentation. Ultrasonic Level Transmitters & Ultrasonic Level Sensors can be used for Non-intrusive level detection of sealed tanks. It can be used for liquid level detection of unsealed tanks and open channels such as rivers.

Hope you can purchase Ultrasonic liquid level sensors at the best price after reading this:

Extended Reading: Procurement Guide for Ultrasonic liquid level sensors

Liquid Level Gauge also called Liquid level indicator. Liquid Level Gauge has contact and non-contact type. Here mainly discusses the non-contact Liquid Level Gauge, which is used for CO2 cylinder level measurement.

Portable co2 bottle liquid level gauge uses ultrasonic non-contact measurement technology. Detect and display the presence or absence of the Co2 cylinder liquid level. The Digital portable liquid level gauges are designed to offer a simple, accurate, rapid and reliable method. Determining the liquid level of high or low pressure CO2, Halon, FM200, Propane, Novec 1230 and any liquefied gas under pressure. No need to move or weigh the cylinders.

Read More about CO2 Cylinder | Portable Liquid Level Gauge.

Ultrasonic Level Switch-External Mounted

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

Ultrasonic Non-contact Liquid Level Controller

The Liquid Level Controller is attached to the outside of the tank. Non-contact detection of tank liquid level. Liquid Level Controller supports liquid level alarm, fault alarm, and 485, Modbus, 4-20mA, FoundationFieldBus, PROFIBUS or Hart.

Liquid Level Controller is installed outside the tank. The HS-ULC-Pro Liquid Level Controller works based on the principle of ultrasonic waves, and is also called “externally attached liquid level switch. It is mainly used to detect the liquid level of the storage tank, and its sensor (digital probe) acts on the outer wall of the storage tank. It supports upper and lower limit alarms, tanks Body temperature display or monitor whether there is liquid in the pipeline. Liquid Level Controller is suitable for liquid level process control in the pharmaceutical, petroleum, chemical, electric power and other industries. For the monitoring of toxic, highly corrosive and dangerous liquids, HS-ULC-Pro Ultrasonic Non-contact Liquid Level Controller is an ideal choice.

Extended reading: Diesel fuel tank level gauges & indicators

All of the above are Non Contact Liquid Level measurement techniques. If you need to contact the medium to measure, you can consider using Liquid level float switches & sensors.

Extended reading: GWR Solid Level Sensor-Cement silo-Ash powder measure


The representative products of non-contact liquid level measuring instruments are ultrasonic level meters and intelligent radar level meters. The working principle is to calculate the distance between the sensor and the measured object through the time of transmitting the signal and receiving the signal. Since the propagation speed in the air is constant, the distance between the liquid level sensor and the bottom of the container is constant, and the liquid level of the measured object can be known.

The non-contact level sensor means that the level can be detected without contacting the liquid. Under this advantage, the application field of the non-contact liquid level sensor has been greatly expanded.

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

The sensor that can measure the liquid level is the liquid level sensor. There are many kinds of common liquid level sensors. For example: float level sensor, hydrostatic level sensor, ultrasonic level sensor, radar level sensor, etc.

Different types of liquid level sensors work based on different principles.

For example, a commonly used water level sensor:
Liquid level sensor (hydrostatic level gauge/liquid level transmitter/liquid level sensor/water level sensor) is a pressure sensor that measures liquid level. The hydrostatic submersion type liquid level transmitter (liquid level gauge) is based on the principle that the static pressure of the measured liquid is proportional to the height of the liquid. The isolated diffused silicon sensitive element or ceramic capacitive pressure sensitive sensor is used. Convert static pressure to electrical signal. After temperature compensation and linear correction, it is converted into a standard electrical signal (usually 4~20mA/1~5VDC).

Related Liquid Level Measurement Solutions

The Secret of Water Level Control

Water level control refers to the control of high and low water levels by mechanical or electronic methods. It can control solenoid valves, water pumps, etc. to become an automatic…

80GHZ Radar Level Transmitter

80 GHz Radar Level Measurement 80GHZ Radar Level Transmitter refers to a frequency modulated continuous wave (FMCW) radar product operating at 76-81GHz. It can be used for level measurement of…

External Tank Level Indicator

External Mounted Tank Level Sensors External Tank Level Indicator refers to an externally mounted level sensor. It is used to install on the outside of the liquid storage tank to…

Magnetic Level Gauge/Indicator

What is a magnetic type level gauge? A magnetic Level Gauge is also called a magnetic level indicator. Magnetic Level Gauge is developed based on the principle of buoyancy and…

Tank Level Gauges & Indicators

Tank level gauges are instruments used to indicate and control the height of the liquid level in the tank. Commonly used in water storage tanks, oil storage tanks, and underground…

Laser Level Transmitter

What is a laser level transmitter? A laser level transmitter is also called a laser level meter. Industrial Accurate, non-contact, and uninterrupted real-time monitoring of material height. Designed for material…

Oil-water Interface Level Measurement Guide

Interface level measurement is very important for oil and gas, chemical tanks. At the same time, Interface level measurement is also a measurement and control challenge. In today’s increasingly modernized…

Sino-Inst offers over 20 Non Contact Liquid Level Sensors and transmitters for level measurement. About 50% of these are ultrasonic liquid level meters, 40% is the level switches.

A wide variety of Non Contact Liquid Level Sensors and transmitters options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of Non Contact Liquid Level Sensors and transmitters instrumentation, located in China.

This entry was posted in Level Measurement Solutions, Blog by KimGuo11. Bookmark the permalink.

About KimGuo11

Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects. Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.