Types of Level Gauge:
Level measurement gauge are of seven types. Each type of transmitter works in a different way, and makes it useful for different types of processes.
- Capacitance Level Gauge
These gauge use liquid stored in a tank or container as a dielectric medium between two or more electrodes. The energy capacity of the capacitor circuit increases when there is more liquid, and decreases if there is less liquid. By measuring the variations in the capacitance value, capacitance level gauge can calculate the current fill level of the tank or container.
- Hydrostatic Level Gauge
Also known as pressure level gauge, these gauge help in determining fluid contents of a container by measuring the pressure of resting body of the fluid within it. The greater the force of liquid, the greater the volume of fluid.
- Magnetic Level Gauge
These gauge use a magnetic object, which is suspended in a buoyant float. This is usually in a narrow auxiliary column, to restrict lateral movements of the float. While the float is on top of the liquid, the movement of the float is measured by a different magnetic device. This allows a precise and stable fill level to be transmitted. This method is suitable for continuous measurement owing to the tendency of the float to rise or sink based on the liquid level.
- Radar Fill Level Gauge
These gauge work on the principle of a radar by using radio wave emissions. These gauge are normally mounted at the top of a tank filled with a liquid. The transmitter sends a radar signal into the liquid, and receives a reflection of the signal. The gauge then analyze the current fill level of the tank based on the time taken by the transmitted signal to return.
- Ultrasonic Level Transmitter
In this type of transmitter, an ultrasonic transducer is mounted at, or near the top of a container containing liquid. The transducer sends out an ultrasonic pulse. The pulse hits the surface of the liquid, and gets reflected. The sensor then calculates the fill level based on the time between the transmitted and received signal.
- Guided Microwave Level Gauge
These gauge work by sending a microwave pulse through a sensor cable or rod. The signal hits the surface of the liquid, and travels back to the sensor, and then to the transmitter housing. The electronics integrated in the transmitter housing determine the filling level based on the time taken by the signal to travel down the sensor and back up again. These types of level gauge are used in industrial applications in all areas of process technology.
- Liquid Level Gauge
These gauge are engineered for detecting levels of liquids. Liquid level gauge are also used for detecting interfaces between two different liquids such as oil and water. Liquid level gauge are mainly used for liquid-level sensing in storage tanks, transport tanks, as well as water storage tanks. These pressure gauge measure the level by measuring the head pressure of liquid.