Photoelectric Level Sensor for 6–13mm Tube, NPN Output

Based on the difference in refractive index between liquids and air, when no liquid is present inside the sensor tube, light emitted by the transmitter travels along the tube's curvature to the receiver. When liquid is present, light cannot pass through, enabling detection of liquid presence. This design features output switching, adjustable sensitivity, easy installation, and eco-friendly construction.

Photoelectric level sensors are suitable for most common liquids, including pure water, drinking water, alcohol, acid/alkali solutions, engine oil, diesel fuel, coolant, etc. Since their principle relies on refractive index differences, they do not require high liquid transparency—functionality is ensured as long as the liquid's refractive index differs from air. Note: Certain high-viscosity liquids or those containing significant bubbles/suspended particles may impair probe-liquid contact, causing response delays or reduced sensitivity. Compatibility should be verified based on specific medium characteristics during selection.

With a compact, sealed design and no mechanical wear, photoelectric level sensors typically require minimal maintenance. To ensure long-term measurement stability, periodically inspect the probe surface for scale, oil residue, or deposits, as contaminants can affect infrared light refraction and reflection, leading to misreadings. For level sensors used in hard water, oily solutions, or chemical environments, perform quick wiping and cleaning at regular intervals.