A capacitive level gauge, also referred to as a capacitance type level sensor or transmitter, is an advanced instrument used for measuring the level of liquid or solid substances in tanks or vessels. This innovative technology relies on the principle of capacitance, which refers to the ability of two conductive surfaces separated by an insulating material (dielectric) to store electrical charge. In this case, the tank acts as one electrode while a probe functions as another. As the liquid fills up the tank and comes into contact with both electrodes, it forms a dielectric that alters the overall capacitance value between them. By monitoring this change in capacitance using sensitive electronic circuitry and algorithms, accurate measurements can be obtained regarding the substance's level within the vessel. The working principle revolves around how changes in dielectric constant impact capacitance levels: when there is more liquid present, thereby increasing its permittivity relative to air or vapor space above it, there will be a corresponding rise in measured capacitance values from baseline readings taken during empty conditions. Thus, capacitive level sensors provide real-time information about material levels for applications across various industries such as oil and gas refineries, chemical plants, food processing facilities and more due to their high accuracy and reliability capabilities.

Capacitive level sensor is based on the principle of capacitance sensing. When the height of the measuring electrode changes by the measured medium, the capacitance changes. It can convert the changes of various material levels and liquid level medium heights into standard current signals, which are remotely transmitted to the operation control room for centralized display, alarm or automatic control by secondary instruments or computer devices. Its good structure and installation method can be applied to high temperature, high pressure, strong corrosion, easy to crystallize, anti-blocking, anti-freezing and solid powder and granular materials.

Capacitive liquid level sensor fundamentally deals with the influence of temperature, humidity, pressure, material conductivity and other factors on the measurement process, so it has extremely high anti-interference and reliability. It can measure strong corrosive liquids, such as acid, alkali, salt, sewage, etc. It can measure high temperature and high pressure media; process temperature -40℃~ +80℃, -70～+260℃(optional); process pressure -0.1MPa ~ 0.5MPa. A single intelligent integrated capacitance level gauge has a common two-point on-site calibration skill, which provides convenience for users to easily use the product.

5. Perfect over-current, over-voltage and power polarity protection.

The working principle of capacitive level sensor:

The advantages and disadvantages of capacitive level gauges:

The measurement of the capacitive level sensor mainly depends on the capacitance change between the two electrodes, which means that the sensitivity of the capacitive level gauge depends on the difference of the dielectric constants of the two media, gas and liquid. The measurement of the capacitance level sensor must ensure that the dielectric constants of the two media remain the same, otherwise the change of the dielectric constant will directly cause errors.

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