How Does It Work? The Core Principle

The operation is based on a simple physics formula:

Pressure (P) = Density (ρ) × Gravitational Acceleration (g) × Height (h) of Liquid

• The transmitter has a sensing element (a diaphragm) at its tip.

• This diaphragm detects the pressure created by the weight of the liquid above it.

• The transmitter's internal electronics convert this measured pressure into a level reading.

• To account for atmospheric pressure changes (which would affect the reading), most transmitters are vented. A small capillary tube inside the cable allows the internal reference side of the sensor to equalize with the atmosphere. If the vessel is pressurized, a sealed or gaugereference is used.

Key Advantages

• Simple Installation & Maintenance: No need to drill holes in the side of the tank. Installation and removal can often be done without emptying the tank.

• No Moving Parts: Highly reliable, minimal wear and tear, and reduced maintenance.

• Suitable for Deep Applications: Ideal for measuring levels in very deep tanks or wells (e.g., hundreds of meters).

• Versatile: Can be used in a wide range of liquids, including water, wastewater, oils, fuels, and some chemicals (with compatible wetted materials).

• Cost-Effective: Generally less expensive than radar or ultrasonic transmitters, especially for simple applications.