What Is an Ultrasonic Level Meter?
An ultrasonic level meter is a device that measures the level of a liquid or solid by the reflection of ultrasonic waves.
An ultrasonic generator emits ultrasonic pulses from the transmitter and measures the time it takes for the pulses to be reflected back to the receiver. Ultrasonic level meters can be applied to measure the liquid level of various materials because it can measure the level of liquids without contact. They are especially used for hazardous substances and high-temperature liquids, where direct human contact is difficult.
It is characterized by the fact that it is not affected by density or conductivity, and thus can make very precise measurements. In addition, the propagation speed of ultrasonic waves is fast, and the accuracy of measurement results is high. Some ultrasonic level meters also have the ability to compensate for measurement errors using signal processing technology.
An ultrasonic level meter has a robust construction and can be used stably over a long period. In addition, since they are non-contact measurements, the sensor parts tend to be less prone to wear and contamination. Therefore, maintenance is relatively easy.
Applications of Ultrasonic Level Meters
An ultrasonic level meter is used in various fields and applications. In particular, they are often used for the purpose of measuring liquid levels in containers and tanks.
In the energy industry, they are used to monitor levels in oil and gas storage tanks. Inventory control and replenishment planning can be optimized. In chemical plants, they are used to measure chemical tank levels, such as sulfuric acid, to help control and ensure the safety of production processes.
They are sometimes used as sensors in cough flow meters to measure flow rates. A cough flowmeter is a device that provides a weir plate for the fluid conductor and measures the upstream liquid level to determine the flow rate. Because of its simple structure, this flowmeter is widely used in open flow paths.
It is also sometimes used to measure the level of powders as well as liquids. In the mining industry, it is often used to control the storage of ore tanks and tailings containers by measuring their levels.
Principle of Ultrasonic Level Meters
An ultrasonic level meter is a device that uses the principle of ultrasonic waves to measure the level of liquids and solids. The device has an ultrasonic generator that generates ultrasonic waves. The ultrasonic generator uses devices, such as transducers and piezoelectric elements, to generate ultrasonic pulses.
The ultrasonic pulses emitted propagate through a medium, such as air or liquid. The sound waves have a high frequency that exceeds the human hearing range (20 Hz to 20 kHz). When ultrasonic waves reach the surface of an object, some are reflected and introduced into the ultrasonic level meter’s ultrasonic receiver.
The receiver measures the arrival time of the reflected ultrasonic waves. The measured time is the time it takes for the ultrasonic waves to travel from the transmitter to the object and back, allowing the distance to the object to be estimated.
Types of Ultrasonic Level Meter
There are two types of ultrasonic level meter: separate type and integrated type.
1. Separate Type
The separate type is an ultrasonic level meter in which the controller and the sensor are designed as separate units. The units are connected to each other with cables, and the signals of the sensor component are transmitted to the processing unit.
The separate type is characterized by the fact that the computing and processing components can be located away from the tank, so there are fewer restrictions on where the sensor can be installed. It is suitable when the appropriate control part is located in a remote area. In addition, the sensor part is less affected by liquids and solids, and can be used in high-temperature or corrosive environments.
If the tank is high in the overall length, the controller section is often installed at the bottom. This makes it possible to check the liquid level display on the controller without having to climb to the top of the tank.
2. Integrated Type
The integrated type is an ultrasonic level meter in which the sensor and the control unit are integrated. Since the sensor and control portions are integrated, it is compact and easy to install. It is usually mounted directly on a liquid or solid tank, and measurement and control are performed in the same device.
Since the sensor and control portions are integrated, there is less complicated wiring and connections. In addition, the sensor and control portions are linked, making communication and settings easy and operation simple.