Liquid detection is critical to several industrial sectors
Reliable liquid detection is critical to various industrial sectors, including plant engineering. Elesa has released two new products to help these industries meet these needs: the HSC capacitive level sensor and the HSO optical level sensor
The HSC capacitive level sensor is designed for conductive liquids and non-conductive liquids, and the HSO optical level sensor is suitable for translucent liquids.
HSC
The HSC model expands on capacitive technology, utilising a conductive electrode coated in PTFE, inserted directly into the tank or container where the liquid level needs to be detected. Its operating principle depends on the variation in electrical capacitance within the tank. The probe and the surrounding metal walls form a capacitor whose capacitance changes in accordance with the liquid level.
As the fluid level rises, the probe's electrical capacitance increases, enabling precise detection. This means that, in practice, capacitance is low when the tank is empty and high when the tank is full.
This solution is versatile and suitable for conductive fluids such as oils and diesel fuel (O version) and water (W version). The operating temperature range is –30 to +125 °C, and the pressure resistance is up to 50 bar.
HSO
The HSO optical sensor can detect the presence or absence of liquids by exploiting the different refraction of the generated infrared beam. The beam is fully reflected to the receiver when no liquid is present, whereas when liquid is present, the prism's refractive index changes and part of the infrared beam is dispersed into the liquid, causing the output to switch.
No direct contact with the liquid is required for this technology to work. It can be installed horizontally or vertically, making it reliable and practical in challenging operating conditions. It can withstand pressures up to 100 bar and temperatures between –30 and +110 °C.
Both the HSC and the HSO share multiple advantages, including compact size and simple construction, low energy consumption, minimal maintenance, and no mechanical parts are subject to wear. Their differences are highlighted by the responses they offer to level control needs: the HSC is for versatility and resistance in harsh environments, while the HSO is for applications where compactness, hygiene, and optical precision are vital.
