I. Working Principle of Ultrasonic Level Gauge

The ultrasonic level gauge is a non - contact level measuring instrument based on the principle of sound wave reflection. Its core technology achieves accurate distance measurement through the emission and reception of high - frequency ultrasonic pulses. The specific working process can be divided into three stages:

1. Sound Wave Emission: The ultrasonic transducer (probe) emits high - frequency sound wave pulses (usually with a frequency of 20kHz - 200kHz) towards the surface of the measured medium.

2. Signal Reflection and Reception: After the sound wave encounters the liquid surface or the surface of solid materials, it is reflected back to the probe and converted into an electrical signal.

3. Data Processing: The microprocessor accurately calculates the time difference between the emission and reception of the sound wave. Combined with the speed of sound (dynamically compensated by the built - in temperature sensor), the distance from the probe to the medium is calculated according to the formula S = C×T/2, and finally converted into the liquid level height.

 

II. Core Components and Technological Innovations

1. Ultrasonic Transducer: It adopts a physical sealing design (IP68 protection level) to ensure stable operation in corrosive, high - temperature, or dusty environments.

2. Processing Unit: It integrates a dynamic temperature compensation algorithm, and the error can be controlled within ±0.2% FS. It supports multi - pulse signal processing to enhance anti - interference ability.

3. Output Module: It provides various output forms such as 4 - 20mA analog signals, RS485/RS232 communication, and relay control, which are compatible with PLC and industrial control systems.

 

III. Key Advantages and Performance Parameters

1. Non - contact Measurement: It is suitable for highly corrosive, viscous, or flammable and explosive media (such as petroleum storage tanks and chemical raw materials), avoiding medium pollution or equipment wear.

2. High Precision and Stability:

    - Regular accuracy: ±0.25% FS, and the metering - grade model can reach ±0.1% FS.

    - Resolution: 1mm, meeting the requirements of high - precision scenarios such as food and medicine.

    - Temperature compensation range: - 40℃~ + 150℃. The dual - sensor design optimizes the measurement accuracy under high - temperature working conditions.

3. Environmental Adaptability:

    - Measuring range: Small range (0.3 - 5m), medium range (0.5 - 15m), and large range (1 - 30m).

    - Anti - interference ability: It uses a balanced noise - suppression receiving circuit to suppress interference echoes such as bubbles and foams.

 

IV. Industrial Application Scenarios

1. Petroleum and Chemical Industry: Liquid level monitoring of large oil storage tanks (suitable for flammable and explosive environments) and level control of reaction kettles.

2. Water Treatment and Environmental Protection: Water level detection in sewage treatment tanks and flow monitoring in rivers and canals.

3. Food and Pharmaceutical Industry: Liquid level monitoring in filling lines and material height measurement in sterile containers.

4. Energy and Metallurgy Industry: Safety alarm for boiler water level and level management of slurry tanks.

 

V. Key Points for Selection and Installation

1. Selection Guide:

    - The measurement blind zone should be lower than the lowest liquid level (the regular blind zone is 0.1 - 0.5m).

    - In high - temperature environments, the split - type structure is preferred to separate the probe from the signal processing unit.

2. Installation Specifications:

    - The probe must be perpendicular to the liquid surface to avoid signal interference from obstacles in the tank (such as ladders and heating pipes).

    - For outdoor installation, a rain - proof bracket should be configured. The probe should be at least 40cm away from the liquid surface to avoid the blind zone.

    - For closed containers, a suitable flange opening (DN65 or above) should be reserved to ensure effective sound wave propagation.

 

VI. Trend of Intelligent Upgrade

With the development of Industry 4.0, ultrasonic level gauges are accelerating their evolution towards digitalization and networking. For example:

- It supports wireless GPRS transmission to realize remote monitoring and linkage with the pump control system.

- It integrates a self - diagnosis function to provide real - time feedback on faults such as probe fouling and abnormal temperature, reducing operation and maintenance costs.

 

Thanks to its non - contact operation, high precision, and strong adaptability, the ultrasonic level gauge has become a benchmark device for modern industrial automated liquid level measurement. In the future, it will continue to promote the improvement of process control efficiency and safety.