Tank gauging systems are used to monitor and manage the level of liquids in storage tanks. These systems employ various sensors to accurately measure and transmit data about the liquid level, temperature, and sometimes other parameters. Here are some common types of sensors used in tank gauging systems:
- Float Level Sensors: These sensors use a buoyant float that moves up and down with the liquid level. As the float moves, it either directly or indirectly (using a magnetic coupling) transmits the level information to a gauge or transmitter.
- Radar Level Sensors: Radar sensors use electromagnetic waves to measure the distance from the sensor to the liquid surface. They are non-contact sensors and are suitable for various types of liquids, including corrosive or volatile substances.
- Ultrasonic Level Sensors: Ultrasonic sensors use sound waves to measure the distance to the liquid surface. They are suitable for both liquid and solid materials, providing a non-contact measurement method.
- Pressure Transmitters: These sensors measure the pressure exerted by the liquid in the tank. The pressure is then converted into a level measurement. It’s important to consider the density of the liquid when using pressure transmitters.
- Capacitance Level Sensors: These sensors measure the change in capacitance between the sensor and the tank wall as the liquid level changes. The capacitance is directly related to the dielectric constant of the liquid, allowing for accurate level measurement.
- Guided Wave Radar Sensors: Similar to radar sensors, guided wave radar sensors use electromagnetic waves, but they are guided along a probe or rod extending into the tank. This method is useful for liquids with low dielectric constants or in tanks with obstructions.
- Magnetostrictive Level Sensors: These sensors use the principle that a magnetic field changes along with the level of a magnetic float. As the float moves up or down, the change in the magnetic field is detected and used to determine the liquid level.
The choice of sensor depends on factors such as the type of liquid, tank size, environmental conditions, and accuracy requirements. Tank gauging systems often integrate these sensors with control systems, allowing for real-time monitoring, data logging, and, in some cases, remote access for efficient inventory management. The use of a combination of sensors in a tank gauging system ensures accurate and reliable measurements for various applications and industries, including oil and gas, chemical processing, and water treatment.